Prepared by:- Bilal A.M.Prepared by:- Bilal A.M.Faculty of dentistry-Faculty of dentistry-

Mansoura university - Mansoura university - EgyptEgypt

Tracing roentgenograms Instruments required for tracing: (1) Paper: Trace a lene or acetate paper (0.003)" thickness, one side

glossy and one side matted, has good transparency even when seven or eight tracings are super-imposed. Other transparent waterproof paper maybe used.

(2) T. square: Makes parallel and projected lines easier to trace. (3) Pencils: Hard and soft pencils indifferent colours. A hard pencil (NO. 10) is used for accuracy, that is true for

well defined lines as: The contour of the profile and the lower border of the mandible.

A soft pencil (NO. 3) is used for the rest of the stractures as seen on the film, which have a certain thickness, close to 1mm. as: supra or bital roof, the palate, the contour of the teeth (un less perfect superimposition)., the clivus. As it becomes more accurate and decreases the amount of individual errors. (4 H) pencil should be used if the tracing is to be made on paper. (2 B) pencil be used if the tracing is made directly on the film. Coloured pencils: will help when doing an analysis, many lines cross in nearly the same area.

It is of good routine to use one colour for the midsagittal structures and an other for bilateral ones. This help to

keep in mind that the flat surface of the film represents depth and volume.

(4) viewing box: Should be large enough to accommodate the lateral and

posterior – anterior films simultaneously. It is advisable to trace an inch grid with thin lines on the transparent surface with India ink. This helps orient the

films.

The light should be cold, two or three intensities of light controlled by switch is important because the films or their different areas do not have the same darkness. To see the soft – tissue of the profile, hide bony structure and use the most intense light.

If one area is not clearly differentiated, look through a black paper cone only at this area .

A photo – retouching table or a box constructed with two (10 – watt) fluorescent bulbs and a milk glass cover the size of (8 x 10) inch film can be

used. It should be possible to vary the amount of light.

(5) A transparent millimeter rules 12 mm long. (6) Two triangles (one small and plain, one large).

(7) A small protractor, long arm dividers, and an artgum eraser. And paper clipsor scotch tape.

Tracing technique:

•1- Distinguishing marks should be put on the right and left sides of the roentgenogram.

•2- Place the roentgenogram on the tracing table, place tracing paper on top of the film, attach the left hand margins of the paper to the corresponding side of the film with scotch – tape or paper clips to permit folding the tracing paper back to check direct by on structural details use a hard fine pencil line.•

•3- Profile tracing: Should be started from the outer out line of the roentgenogram and continued to the inner parts:Trace the soft tissue profile while hiding the rest with a black paper.

Then, trace the bony profile:

A- The lower border of the mandible, posterior border of the ramus, draw the posterior border of

the brain case. B- Locate the foramen magnum.

C- Trace the odontoid process of the axis, go up ward and trace the clivus up to sella turcica (part of and trace the clivus is hidden by the ear rods), forward and upward, trace the roof of the orbit up to the supra orbital ridge. Here, come down word tracing the laTeral and lower borders of the orbit.

D- Come back to sella turcica and trace the planum, and anteriorly the cribriform plate, continued more anteriorly and upward by the inner plate of the frontal bone.

E- In the midface, trace the palate (floor of nose and roof of mouth), posterior by the pterygo maxillary fissure, just below and behind the palate, trace the soft – palate, the pharyngeal wall, and the root of toungue.

F- Trace the teeth, mainly the first permanent molars, the canines, and the most prominent incisors

Tracing in details: 1- The soft tissue profile:

Only on the lateral films, it does not offer any difficulty if the film is not burned out, if the viewing box has in tense light,

and if the bony structures are hidden by a black paper. Possible deformations:

At the level of nasion, some cephalostats use a rest against that area and the out line of the soft tissues is pressed in.

At the level of the lips and chin, the outline is different (changing the position of the landmarks).

When the lips and mental muscles are at rest or in contraction. This difference, may have a diagnostic value

concerning the vertical shortness of the lips, compared to the bony anterior lower face.

At the level of nasion, some cephalostats use a rest against that area and the out line of the soft tissues is

pressed in. At the level of the lips and chin, the outline is different (changing the position of the landmarks).

When the lips and mental muscles are at rest or in contraction.

This difference, may have a diagnostic value concerning the vertical

shortness of the lips, compared to the bony

anterior lower face.

2- The bony structures: From above to down: (1)The frontal bone:

The external plate goes down ward with a convexity at the level of the supra orbital ridge, to nasion. The

internal plate continues, the cribriform plate upward between the external and internal plate. The frontal

sinus can be located with varying size. At the level of the frontal sinus, the supra orbitale can be located.

2-The nasal bone:Starts from nasion and goes down ward and forward,

it is continued down ward and backward to form the lateral wall of the nasal cavity, it meets the floor of

the nose at naso spinale.

3-The maxilla: The anterior contour of the palate and the a lveolar bone. Extend on the profile between the anterior nasal spine to curve back ward in a concavity at the deepest point of which lies point A. (subspinale). It continues anteriorly down ward, up to the junction with the incisor at prosthion. .

4-The incisors: The most prominent one should be traced, the upper central incisors does not offer difficulty, but in the lower, the four incisors are super imposed and the apices are very difficulty to differentiate

5- The chin: Start at infra dentale, curves posteriorly to point B (supra – mentale), goes down ward and forward to pognoion, curves back ward to gnathion and menton, and it continued to form the internal plate of the symphysis back to the incisors lingually.

6- the mandible: posterior to the symphysis, the lower border extends to the gonion, at the level of the bicuspids, it has a convex shape, and is concave at the level of the insertion of the masseter (antegonial notch) it curves to reach gonion.

7- The ramus: Upward and backward up to the neck of the condyle which is more backwardly inclined. The posterior border can be followed up to the point (articulare) where it is shadowed by the basisphenoid.

8- The head of the condyle: Unless an open mouth film is token it can not

be accurately located, as it being masked generally by the ear rods of the apparatus

used. 9- The coronoid process:

Can be located but not with enough accuracy to be used for land marks.

10- The alveolar process: Is difficult to locate accurately, may be

guessed.

3- Upper face: It is the area between the cranial base and the

palate. Antero – posteriorly we find: (1)The orbit:

The roof has been defined as double lines go down ward from the supra orbital ridge to lower most

point orbitale.

The midlines between the two shadows should be defined oblique

line crosses the orbital cavity. It represents the greater wings of

sephenoid in the frontal film.

(2) Maxillo – zygomatico – temperal sulcus: It is a vertical line which can be straight or like situated just posterior to the lateral contour of the orbit, but extending farther below.

It goes from the cribri from plate, down to the floor of the nose at the level of the upper first molar, and curves upward toward orbitale. The lower most point at the curvature is the key-ridge being bilateral, the midline between the two shadows should be taken.

(3) The pterygo maxillary fissure Ptm: It forms a boucle just above and posterior to the posterior nasal spine and the soft palate. Its anterior contour represents the tuberosity of the maxille. Its posterior contour represents the ptergoid bone which is difficult to trace. Being bilateral, the midline between the two shadow should be taken.

4- Midlface: It is represented by the hard palate which is

enclosed between the floor of the nose and the roof of the palate.

It extends from anterior nasal spine to posterior nasal spine (This land mark may be masked by

the last molar).

At the level of Ptm it makes a U-turn and comes anteriorly to the upper central

incisor from the alveolar process of the incisor area.

5- Cranial base: Cranial base is the demakration that the brain makes with

the face and the neck. Traditionally, it is divided into anterior, middle, and

posterior fossae.

A- Anterior cranial fossa: Extends from the frontal bone to the lesser wing of

sphenoid. It represented bilaterally by the roof of the orbits, and in the median plane by the cribriform plate

of ethmoid and the planum sphenoidale.

B- Middle cranial base: Extends from lesser wing of sphenoid to the

petrous bone.

petrous bone

C- Posterior cranial fossa: Extends bilaterally from the occipital bone

posteriorly and the petrous bone anteriorly. In the median plane it comprises the occipital bone, the foramen magnum, the clivus up to

sella. As can be seen, the three fossae overlap

antero-posteriorly.

6- cranial base lines: 1- Posterior arm (The clivus):

It extends between the foramen magnum and sella turcica on the mid sagittal plane. On the lateral film, it can be located at both extermeties but it is masked in its midsection by the ear rods. It is composed of the occipital and the sphenoid bones. The sulture or synchondrosis between them is difficult to locate. At the lower end it starts at basion situated just above the tip of the odontoid process of the axis, goes obliquely upward, crosses the instru-mental porion and continues up to the posterior clinoid of sella turcica.

2- The hinge (sella – turcica):Saddle shaped , pituitary fossa, situated on the mid

sagittal area at the centre of corpus sphenoidale. On the lateral film, its curved contour extends from

anterior to posterior clinoids.

In the body around sella, there is a sphenoidal sinus of varying size.

In roentgenographic cephalometry, because its accurate delineation, points have been defined all

around its contour and at its center.

3-Anterior arm: Divided in two lines, the roof of the orbit above and the planum with the cribriform plate below:

A- Roof of the orbit: Bilateral, there fore, often two master shadows on the lateral film festooned by small crests on

its superior surface. The midline and the general direction should be taken and can be

represented by a continuous line starting at anterior clinoid, crossing the supra orbital ridge.

B- Planum: Is separated from the orbital roof and anterior

clinoid just anterior to sella. It is flat and horizontal. It joins the cribriform plate at the level of the lesser

wing. C- Cribriform plate:

It represented by doted lines, it continues forward and curves slightly upward to join the internal plate

of the frontal bone. D-Crista galli:

Sometimes visible on the lateral, but dimly at the junction between ethmoid and frontal inner plate.

7- The teeth: The accuracy in drawing the teeth depends on their symmetry and the good orientation of the

head. The key teeth to trace are first permanent

molars, the canines, and the central incisors. 1.Molars:

Are generally well defined, on the occlusal surface no attempt should be made to draw

each cusp, it may be the source of too many errors. Instead on approximate line

demarcating the occlusal surface of upper and lower first permanent molars is enough.

2- Canines: Not always easy to locate. One method may be to start from the molars and eliminate progressively, the bicuspids, then start from the incisors and go in opposite ways eliminating the laterals. This may be used for both lateral and postero-anterior cephalogram.

3- Incisors: The upper offer little difficulty. On the lateral the apex may sometimes be masked or not very sharp. The lower central incisor offers more difficulty as the four lower incisors are aligned nearly at the same level and have approximately the same size.

Any measurement involving the axis of the lower incisor should be allowed a large

margin of tracing errors. Besides these key teeth, the others (except the lower and upper lateral incisors) do not

offer much difficulty. Postero – anterior tracings should show the

following: 1- The contour of the cranium.

2- The mastoid. 3- The lateral out lines of the ramus. 4- The lower border of the mandible.

5- The coronoid process.

6- The orbital lines. 7- The lesser wings of the sphenoids. 8- The crista galli. 9- The nasal septum. 10-The lateral walls of the nose.

Location of the porion: The porion is not distinguishable on the roentgeno-

gram. It actually is approximately 3mm. above the ear rod. The external auditory meatus used in

cephalometrics for head fixation is not as a rule on the same bilateral plane and the integuments do not

always rest on the ear posts.

Since the tissues of the outer ear canal are sensitive to pressure, insertion of the ear rods in the same

position is uncertain.

Determination of the right and left sides: •In all cephalomertic roentgenograms the centeral

ray goes through the ear rod or porion, the maxillary left first molar is closer to the ear rod than the

maxillary first right molar. •The maxillary canine left is closer than the

maxillary right canine. •The left jugal buttress is closer than the right.

•The lower border of the body of the mandible on the left side is superior to the corresponding borders

on the right side. •The posterior border of the ascending ramus on the

left side is distal to that of the right.

•The left side of the mandible is superior to the right, and the line denoting the inferior border must cross

over the corresponding line of the right side in the region of the angle and become the posterior or distal

outline. •The candyle is frequently obsecured by the ear rod image and the petrous portion of the temporal bone.

The tracing may have to be terminated 6 or 8 mm. below the condyle.

•In most films, only the crowns of the molar teeth can be seen easily because of left and right side super

imposition.

•In the incisor region, the full crown usually can be seen a long with the labial root out line. The

lingual root outline from cinulum to apex is usually obscured and must be drawn from a

knowledge of tooth morphology or from a template.

•In the mandible, as in the maxilla, incisor teeth and molar teeth should be traced by

tracing the teeth in rest position, the occlusal surface and incisal margins can be reproduced

accurately.

•To obtain correct condylar morphology by using a template: two profile

cephalograms are taken the one with the teeth in full occlusion is used to measure

angles and lines. The second cephalogram is used to obtain condylar outline. This is taken with the mandible

wide open, and the condyles down ward and forward.

Errors in tracing: •Some degree of error is inherent in tracing film, some errors are duo to the character of the film traced, and

to the person doing the tracing. •Personal errors are recognized as a feature of all

tracings, the experienced tracer will avoid errors duo to in experience.

•Tracing should be limited to those parts necessary for required information.

•It is advised that the tracer, having at hand a set of x ray films and a skull. It is only by comparing, at each

step, on to the other, that clear visualization will emergy and anatomical accuracy be achieved.

•The denser the structure, the whiter the reproduction on the film. Actually only the teeth offer a well delimited and compact delineation. •The reproduction of bony structures depends

on their orientation as well as their density. •This is one of the reasons why the image is

clearer on the lateral than opstero-anterior film. •On the lateral film all structures besides median sagittal plane are bilateral and if

symmetrical they double (for the same structure).

•Practically, even if the face is perfectly oriented and if the bilateral structures are symmetrical, they are not necessarily super imposed because the x-rays are not parallel but divergent. There fore, if double image is seen on the film, it does not necessarily mean asymmetry. However, without the frontal film, it is not possible to decide between asymmetry and malposition. Unless just one structure is asymmetrical. There fore, when double image is present (lower border of the mandible), check if all bilateral structures are double (e.g the roof of the orbit), if not it is a local asymmetry.

•While asymmetry between the two sides of the mandible should be bisected severe asymmetry should be traced as found. •The temperomandibular articulation and the condyle can not be seen on the profile roentgenogram when the teeth are in occlusion and must be traced from a film taken with the mouth wide open. This is used as a template. It will be good to strat with a lateral view, then try to find the corresponding structures on the frontal film. Some of them are clearer on the postero – anterior film than on the lateral and vice versa.

•Some can not be located accurately on either (T.M.J) unless an open mouth is taken.

•Generally, for height and depth proportions use the lateral films and for breadth and

symmetry use the frontal film. •The frontal film in more difficulty to interpret because the structures at different depth are

super-imposed. (e.g) at the level of the odonoid process of the axis.

•The next step is to clear this confusion of lines and shadows, to make a selective interpretation by tracing neatly the most significant structures.

Lateral land marks 1- Nasion (N):

The midlle point on the fronto-nasal suture, intersected by the

median sagittal plane. The junction of the frontal and

nasal bones. The soft – tissue nasion (N):

The most concave or retruded point in the tissue overlying the area of the fronto-nasal suture.

The point of maximum convesity between nose and

fore head.

Cephalometric land marks

2- Sella Turcica (s):Sella trucica is the pituitary fossa of the sphenoid

bone. Sella (s) is the centre of the sella turcica. 3- Se:

The mid point of the entrance of the sella.

4- Subnasale (sn): The point at which the nasal septum between the nostrils merges with the upper cutaneous

lip in the mid sagittal plane.

5- Sub spinale (point A): The deepest midline point in the curved bony outline contour of the alveolar process of the maxilla. At the deepest point between the anterior nasal spine and the prosthion. The anterior limit of the maxillary basal arch.

6- Prosthion (Pr):The lowest, most anterior interdental point on the alveolar mucosa in the median plane between the maxillary central incisors.

7- Incisor superius (I.S): The most forward incisal point of the most prominent

maxillary central incisor. 8- Apicale ┴ (Ap _) :

The root apex of the most prominent maxillary central incision.

9- Incisor inferius (I.I): The most forward incisal point of the most prominent

mandibular central incisor. 10- Apicale T (Ap T):

The root apex of the most prominent mandibular central incision.

11- Infra dentale (I.d): The highest, most anterior, interdental point on the alveolar mucosa in the median plane

between the mandibular central incisors.

12- Supra mentale (point B): The deepest point on the contour

of the mandibular alveolar process betweeninfradentale and pogonion.

13- Pogonion (Pog): Most anterior point of the bony chin.

14- Gnathion (Gn): According to martin and saller (1956): it is the

lowest point in the median plane of the mandible, where the anterior curve in the outline of the chin

merges into the body of the mandible. It is a point on the bony border palpated from

below which lies posterior to the tegumental border of the chin.

In cephalomertic, it is the mid point between the most anterior and inferior points on the bony chin.

Measured at the intersection of the mandibular base line and nasion-pogonion line (facial plane).

(Mandibular plane and facial plane).

15- Gonion (Go): The lowest, posterior and most outward point on the angle of the mandible. This is obtained in cephalometrics by: bisecting the angle formed by tangents to the lower and posterior borders of the mandible.

When the angles of both sides of the mandible appear on the profile roentgenogram, the point midway between the right and left sides is used.

The midpoint in the curve of the mandible between the ramus and the lower border.

16- Menton (Me): The lowest point on the chin, from which the face height is

measured.

17- Articulare (Ar): The point was introduced Bjork (1974)

The point of intersection of the external dorsal contour of the mandibular condyle and the temporal

bone. The mid point is used when the profile roent –

gengram show doubleprojections of the rami. The ventral surface of

the basilar part of the occipital bone intersects

the posterior border of the ascending ramus and the outer marginof the cranial base.

18- Condylion (cd): Most superior point on the head of the condyle.

19- Orbitale (or): The lowest point on the inferior bony margin of the orbit. In cephalometric roentenogram the orbitale located on the lower margin of the orbit directly below the pupil when the patient looks straight a head.

20-Anterior nasal spine (ANS): The median, sharp, bony process of the maxilla at the lower margin of the anterior nasal opening.

21- Posterior nasal spine (PNS):Process formed by the united projecting ends of the posterior borders of the palatal processes of

the palatal bones.

22- Anterior point for the occlusal plane (APocc): A constructed point, the midpoint of the incisor

over bite in occlusion.

23- Posterior point for the occlusal plane (ppocc):- the most distal point of contact between the most posterior Molars an occlusion

24- Basion (Ba): The most forward and lowest point on the

anterior margin of the foramen magnum.Bjork and palling prvide a more specific roent –

genographic definition: The perpendicular projection of the anterior border of the foramen magnum. On a target through the lower

margin of the condylar head.

Other cephalometric land marks: Pterygo maxillary fissure (Ptm):

An oval shaped radiolucency resulting from the fissure between the anterior margin of the pterygoid

process of the sphenoid bone and the profile out line of the posterior surface of the maxilla.

Appears as iverted tear-drops, its anterior margin represents the posterior margin of the tuberosity of the maxilla.

Porion (P): The mid point on the upper edge of the external

auditory meatus. As a cephalometric landmark it is located in the

middle of the metal rods of the cephalometer.

Key ridge (KR): The lowest point of the zygomatico – maxillary ridge.

Acanthion (Ac): Tip of the anterior nasal spine.

Clinoidale (Cl): Most superior point on the contour of the anterior clinoid.

Clinoidale (Cl): Most superior point on the contour of the anterior clinoid.

Bolton point (BP). Spheno occipital synchon-drosis (So).Registration point (R). Bolton point (Bp): The highest point on the profile roentgenogram at the notches on the posterior and of the occipital condyles on the occipital bone.

Broad bent registration point (R): Mid point on a perpendicular from the centre of

sella to the Bolton – nasion line. Spheno – occipital synchondrosis (so):

The cartilaginous union of the anterior end of the basilar portion of the occipital bone and the

posterior surface of the body of the sphenoid bone.

Tragion (T): The notch just above the tragus of the ear. It lies

1-2 mm below the spina helicis which can be palpated.

Alveolar point (Al.P): The lowest point of the a lveolar process at the midline between the maxillary central incisors. Occipital condyle (O.C): The condyle on the occipital bone near the foramen magnum. Opisthion (O.P): The posterior midsagittal point on the posterior margin of the foramen magnum. Opithcranion (OPC): The posterior midsagittal point of the greatest cranial length from glabella.

Sphenoidale (SPH): Point of the greatest convexity between the anterior contour of the sella turcica and planum sphenoidale. Bregma (Br): The anterior end of the sagittal suture where it meets the coronary suture. Cheilion (ch): The lateral terminus of the oral slit i.e. (The outer corner of the mouth). Dorsum sella (D.S): The square shaped bone which forms the posterior boundary of the sella turcica.

Endo basion (E.b): The perpendicular projection of the anterior border of the foramen magnum on a tangent through the lower margin of the condylar head at the foramen magnum. Ethmoid triad (Eth.Tr): A point located on the planum sphenoid, the ethmoid line, midway between the greater wings of the sephenoidale bone. Ethmoidale (Eth): The lowest point on the cribri form plate of the ethmoid bone in relation to the sella – rasion line. The deepest sagittal point on the cribriform plate of the ethmoid bone in the anterior cranial fossa.

Tuber culum sellae (T.S): Anterior boundary of the sella turcica.

Zygoin (Z): The most lateral projection of the zygomaticarch.

Rhinion (RH): The most anterior intersection of the nasalbones, which

forms the tip of the bony nose. Pterygo – maxillare (Ptm):

The point where the pterygoid process of the sphenoid bone and the pterygoid process of the maxilla begin to

form the pterygo maxillary fissure. The anterior wall represents the retromolar tuberosity of the maxilla and the posterior wall is the anterior curve of the pterygoid

process of the sphenoid.The lowest point of the opening is used in cepha-

lometric roentgenogram.

Euryon (Eu): The most lateral point on the side of the head.

Fronto temporale (Ft): The most anterior point of the termporal line near

the root of the zygomatic process of the frontal bone.

Inion (n): The most elevated point on the external occipital

protuberance, at the crossing of the midline with a tangent to the superior nuchal line.

Lambda (La): Intersection of the sagittal and the lambdaidal

sutures on the cranial vault.

Mandibular notch (M.N): The concavity between the coronoid and

condyloid process of the mandible. Ophryon (Oph.):

Mid sagittal point just above the galbella intersecting on arc from the fronto temporalis

across the frontal bone. Vertex (v):

The highest point of the head, in the midsagittal plane, when the head is help erectly or in the

frank fort horizontal position. Postero-anterior cephalometric landmarks:

Poster-antrior cephalomeric landmarks Glabella (Gl):

The most anterior point of the frontal bone in the midsagittal plane of the bony prominence

joining the supra orbital ridges. Trichion (Tr):

The mid point of the hair line at the top of the fore head.

Nasion (N) Tragion (T)Orbitale (O)

Prosthion (Pr) Infradentale (I.D)Gonion (Go) Gnathion (Gn)

Soft tissue points: (Burstone 1959)

Soft tissue points: (Burstone 1959)Glabella (G):

Determined by a tangent to the forehead from a line passing through subnasale.

Soft tissue nasion (N`): The most cocave or retruded point in the

tissue overlying the area of the frontonasal sutures, the intersection of the SN line with

the soft – tissue anterior to rasion.

Nasal crown (Nc): A point a long the bridge of the nose halfway between soft-tissue nasion and pro nasale.

Pronasale (Pn): The most prominent or anterior point of the

nose.

Subnasale (sn): The point where the maxillary lip and nasal

septum form a definite angle.If the depression is a gentle curve, subnasale is

interpreted as the most concave point in this area as measured by a line angle 45 degrees

from nasal floor.

Soft – tissue sub spinale (A`) (ss): The point of greatest concavity in the midline

of the upper lip between subnasale and labrale.

Labiale superius (Ls): The most prominent point on the upper lip as

measured from a perpendicular to nasal floor.

Stomion (sto): The junction in the midline of the upper and

lower lips.

Labiale inferius (Li): The most prominent point on the lower lip as

determined by a perpendicular from nasal floor.

Soft – tissue supra mentale – point B` (Sm):

The point of the greatest concavity in the midline of the lower lip between the soft –

tissue chin and labiale inferius.

Soft – tissue pogonion (Pog`): The most prominent or anterior point on the soft – tissue chin in the mid sagittal plane.

Soft – tissue gnathion (Gn`): The mid point between the most anterior and inferior points of the soft – tissue chin in the mid sugittal plane.

Superior labial sulcus: The deepest point on the upper lip as determined by a line drawn from subnasale inclined so that it forms a tangent with labiale superius.

Inferior labial sulcus: The most concave point on the lower lip as determined by a line tangent to the menton

and labrale inferius. Menton (Me`):

The most anterior and inferior point on chin. Determined by a line tangent to the lower lip

and the chin.

Cephalometric lines and planes:

1- The commenly used horizontal lines and planes: •S – N line:

The cranial line between the centre of sella turcica (s) and the anterior point of the fronto nasal suture (nasion).

This represents the anterior cranial base.

•Bolton plane: (Broad bent – Bolton line): BP- N:

The line connects nasion to the upper most point on the posterior end of the occipital condyles on the

occipital bone. (Bolton point).

•Frankfort horizontal plane (FH): Plane intersecting right and left porion and left

orbitale. It is drawn on the profile roentgenogram from the superior margin of the acaustic meatus to orbitale.

•Palatal plane: Line connecting the anterior nasal spine (ANS) and the posterior ansal spine (PNS).

•Occlusal plane: (OCC)The occlusal plane of the teeth, a line drawn between points representing one half of the incisor overbite and one half of the cusp height of the last occluding molars.

•Mandibular plane: Several mandibular planes are used, depending on the

analysis: The most common ones are:

A.A tangent to the lower border of the mandible. B. A line between gonion (Go) and ganthion (Gn)

steiner.C. A line between gonion

(Go) and Menton (M) tweed.

•Alternative lines and planes: • A.B Plane: Line between A point (sub spinale) and B- point (supra mentale) it represents the anterior points of the basal arches of the jaws to one another and to the facial line.

•Facial plane: A line from the anterior point of the fronto- nasal

suture (N) to the most anterior point of the mandible (Pog).

•Ramus line: A line tangent to the posterior border of the

mandibular ramus either from: A- A point posterior to the mandibular condyle.

B- A point immediately below the condyle.

C- Articulare.

•Orbital plane (O.P): Perpendicular to Frankfort horizontal plane from

orbitale.

•S – BP plane: Line connecting sella with the Bolton

point. This line indicates the posterior portion of the cranial base.

•Anonymous line: Gla bella to opisthion.

•B Jork's line: Nasion to articulare (the point on the profile roentgenogram where the posterior border of

the condyle intersects the contour of the temporal bone.

•Blumenbach's plane: The plane drawn through the points on the skull, without the mandible, which

touch a flat horizontal surface. •Broad bent's line:

Nasion to sella trucia mid point on the profile roentgenogram.

•Broca's line: Prosthion to lowest point on the occipital condyle when the skull is resting on a horizontal surface. •Camper's line:Line from the tip of the anterior nasal spine (acathion) to the external auditory meatus.

•Camper's plane: Line from tip of the anterior nasal spine

(acathion) to the centre of the bony external auditory meatus in the right and left sides.

•Camper's triangle: Camper's line and a line tangent to the facial

profile. •Cranial base length: Nasion to botton point.

•Cranial length: Galbella to opisthocranion.

•De caster's line: The plano-ethmodial line from the anterior

contour of sella turcica to the roof of the cribri from plate and the internal plate of the frontal

bone.

•His's line: Extends from acanthion to opisthion and divides the

face into an upper and a lower dental part. •Hamy's line:

Galbella to lambda.•Montagus line:

Nasion to porion.

•His's line:

•Huxley's line: Nasion to basion. •Krogman's Nassion parallel: Sella – nason to Frankfort horizontal.•Martins line: Nasion to the most elevated point on the external occipital protuberance (inion).

•Margolis line: Nasion to top of spheno occipital

synchondrosis. •Montagus line: Nasion to porion.

•P-O plane: Porion – orbiotale, the Frankfort plane.

•Pterygo maxillary fissure (PTM): The fissure formed by the retromolar

tuberosity of the maxilla and the anterior curve of the pterygoid process of the

sphenoid.•Pycraft's line:

Nasion to centre of bony external meatus of the ear.

•Rickets esthetic line: Tangent to the tip of the nose and the most anterior point on the chin. •Salzmann's basal arch: The basal arch is the area in the jaws which begins at the most constricted point in the body of the maxilla and of the mandible when seen on the profile roentgenogram.

It includes Down's a point (subspinale) and B point (supra mentale), Axel lunds trom's apical base (which is a line around the apices of the fully formed permanent teeth). And extends around the jaws at the most constricted portions of the alveolar processes.

These are the areas to which tweed referred as (basal bone). •Schmidt's plane: Ophryon to inion. •Schwalbe's line: Galbella to ionion.•Spheno ethmoidal junction (S-E): Read as a distance on the S-N line by dropping a perpendicular.

•Super orbital line: A line from the anterior clinoid process a

long the roof of the orbits, bounded anteriorly by the frontal bone and posteriorly

by the sphenoid bone. •Von Baer's line:

Follows the antero posterior axis of the zygomatic arch, tangent to its upper most

convexity.

•Von thering's line: Orbitale to the centre of the bony external meatus (Frankfort horizontal).•Cranial base references planes:•1-The Bolton line (Bolton point – nasion). 2- The sella – rasion line.3- The spheno occipital synchondrosis. 4- The Frankfort horizontal, because of its close relation to the cranial base may also be used.

•Mandibular references planes: •1- A line tangent to the lower border of

the mandible especially when the antegonial notch is extremely pronounce

when the mandibular border shows a decided downward curvature it makes

thisplane highly variable. 2- A line joining gonion and gnathion. 3- A line joining gonion and menton (both points show variability during growth).

•Middle face references planes: •1- The palatal plane (joining ANS and PNS). •2- The occlusal plane which bisects the maxillary first molar cusps and incisor overbite. 3- One of the mandibular planes also may be used, especially in relation to mandibular denture changes.

Cephalometric angles: •Angle of convexity (Downs):

Angle between (nasion – subspinale – pogonion) (N-point A- pog).

This angle is read in positive or negative degrees from zero. If the line pogonion-point A is extended (see dotted line in Fig.) and located anterior to the N-A line, the angle is read as positive.

A positive angle suggests prominence of the maxillary denture base relative to the mandible. A negative angle of convexity is associated with prognathic profile. The range extends from a minimal of -8.5 degrees to a maximal of+ 10 degrees, with a mean reading of 0 degree.

•Facial angle (Downs): Frankfort plane intersection

of nasion – pogonion line (inner lower angle).

Facial angle establishes antero posterior relation of the mandible to the upper

face, at the Frankfort horizontal. (FH-N-POG).

•FMIA (Tweed): Angle between Frankfort plane and the

mandibular incisor plane.This measures the procumbency of the mandibular incisor to Frankfort planer.

•I.A: Internal angle of the mandibule.

•MIA: Mandibular incisor angle. This is used to measure the procumbency of mandibular incisor to the mandibular plane.

•N-S-Gn: Angle between SN line with the line connects N with the chin point (Gn).It is used in locating the anterior end of Go-Gn line.

•N-S-MP: Projection of line SN with a tangent to the lower

border of the mandible (MP).

•N-ANS-PNS: Angle from nasion (N) to the anterior nasal spine (ANS) to posterior nasal

spine (PNS).

•S-N-A angle: Angle between points sella – nasion – subspinale

(point A). It represents antero

posterior relationship of the maxillary basal

arch to the anterior cranial base. This

shows the degree of maxillary prognathism.

•S.N.B angle: Angle between points

sella rasion – supra metnale (point B).

It shows the anterior limit of the mandibular

basal arch in relation to the anterior cranial

base.

•SNA – SNB Angle: The angle formed by subspintale (point A) rasion supramentale (point B). It indicates the antero posterior relationship of maxillary and mandibulary and mandibular basal arches to the anterior cranial base.

•S-N-I: Angle between SN line and the line connects N to

tip of _ (tip of the maxillary central incisor). This is used to

determine the position of the maxillary

incisor to the anterior cranial base.

•B.P – SN (Broad bent): Formed by the lines s (sella) – N (Nasion) and s

(sella) – B.P (Bolton point). By connecting the points B.P and N, the Bolton

plane (B.P – N) is obtained. And the angles

S-B.P-N and S-N-B.P may be ascertained.

•Y-axis angle: It is read at the angle toward the profile of the face below the Frankfort horizontal. It is indicator of the down ward and forward mandibular growth.

•N-S-MI (maxillary first molar): Angle between SN line with S-MI line.

(line froms to the notch between the mesial and the distal cusps of the maxillary first

permanent molar).

Dawn's analysis•The control materials studied was derived from 20 living individuals ranging in age from 12 to 17 years

and equally divied as to sex.•Both the skeletal criteria and the denture criteria

will be discussed.

Skeletal criteria :-Facial angle :- ( 1948 )This angle is an expression of the degree of recession or protrusion of the chine. It is determined by drawing a line from nasion to pogonion, this plane called the facial plane.

•The inferior inside angle of its intersection with the Frankfort horizontal is designated as

the facial angle.•The mean value : 87.8O 3O.

•The range was from 82O ( recessive chin ) to 95O ( protrusive chine ).

•Mansoura measurements :•Male : 86.4O 5O.

•female : 85.7O 5O.•Mean : 86.1O 5O.

•If angle smaller than normal this indicates : A skeletal class II malocclusion, with a retrognathic

mandible.•If facial angle larger than normal this indicates :

A skeletal class III malocclusion, with a prognathic mandible.

•Age changes:- This angle increases with age, as mandibular

growth concides with general growth.

•Angle of convexity :( Na – point A – pog ).

•This is a measure of the protrusion of the maxillary oart of the face in relation

• to the total profile.•The angle is formed by

• two lines, one form •nasion and the other •from pognoion, both• meeting at point A.

•The mean value of the angle is 0O ( the angle of convexity would concide with the facial plane ) and

becomes 180O.•Normally, points N, A, pog fall on a straight line.

•If point A fell posterior• to the facial plane,

•the formed angle was• read in a minus degree

• ( - ) .

•If point A anterior, the angle was read in a plus degree ( + ).

•The rang was + 10O ( convex ) to – 8.5O ( concave ).

•Mansoura measurements :•Male : 4.3O 4O.

•female : 4.6O 2O.•Mean : 4.4O 3O.

•This angle reveals the convexity or concavity of the skeletal profile.•If angle larger than normal this indicates : A skeletal class II malocclusion and a convex skeletal profile ( + ).If angle smaller than normal this indicates : A skeletal class III malocclusion and a concave skeletal profile ( - ).

Age changes :-The skeletal profile becames more concave with age because the mandibular growth usually surpass growth of the maxilla.

•A-B plane to facial plane angle : ( Down's ) :-•The angle formed by the intersection of the A-B

plane with the facial plane ( Na – Pog ).

•It is a measure of the• anteroposterior position

• of the maxillary •denture base and the

•mandibular denture base• to the facial plane.

•Average value : ( - 4.6O 3O ) range ( 0 to – 9O ) .•In normal class I skeletal relationship, where point A is anterior to point B ( or anterior to facial plane ) the

angle is expressed as a ( - ) number.Large negative value

means protrusion of the maxilla and retrusion of

the mandible ( class II relationship ).

•If point A is posterior to the facial plane, the angle is expressed as a ( + ) number.

•Zero and positive measurements indicates class III skeletal malocclusion.

•The location of A-B plane in relation the facial plane is a measure of the relation of the anterior

limits of the maxillary and mandibular denture bases to each other and to the profile.

•It helps the operator in gaining correct incisal relationships and satisfactory axial inclinations of

the incisors and helps to check ANB angle.

•Mandibular plane angle :-( MP to FH )•This is a measure of the relationship between the Frankfort horizontal plane and a tangent to the lower border of the mandible.•The mean value : 21.9O with a range from 28O to 17O .•Mansoura measurements :•Male : 23O 6O.•female : 26O 5O.•Mean : 24O 5O.

•If the angle is larger than normal ( as in skeletal class II division I ) it indicates a vertical growth of

the mandible.•If the angle is larger than normal ( as in skeletal

class II division 1 ) it indicates a vertical growth of the mandible.

•If the angle is smaller than normal ( as in class II division 2 ) growth of the mandible will be horizontal

in nature.

Y-( Growth) AxisThe y-axis is measured as the acute angle formed by the intersection of a line from the sella turcica to gnathion with the Frankfort horizontal plane . This angle is larger in Class II facial patterns than in Class III tendencies.

The y-axis indicates the degree of the downward, rearward, or forward position of the chin in relation to the upper face.A decrease of the y-axis in serial radiographs may be interpreted as a greater horizontal than vertical growth pattern.

An increase in the y-axis is suggestive of vertical growth exceeding horizontal (or forward) growth of the mandible.The range extends from a minimal of 53 degrees to a maximal of 66 degrees with a mean reading of 59.4 degrees.

( In the appraisal of severe malocclusions, where the incisors in extreme positions of supra or infra

occlusion, molars and premolars are used instead of incisors ).

•The angular relation between the Occlusal plane and the Frankfort plane ranged from 1.5O to 14O

with a mean value of 9.3O .•The class II cases have a steep Occlusal plane, the class III cases have Occlusal plane tends to

became more horizontal.

•Denture criteria :-•Occlusal plane angle :-

( OP to FH )•Cant of the Occlusal plane :

In order to make angular readings, the Occlusal plane was

represented as a straight line. by

bisecting the first molar cups height line.

When the anterior part of the plane is lower than the posterior, the angle would be positive. Larger positive angles are found in Class II facial patterns. Long rami tend to decrease this angle.The minimal angular measurement is +1.5 degrees; the maximal, +14 degrees; and the mean, +9.3 degrees.

•Inter incisal angle :-( T to )

•This angle relates the angular position of the long axis of the upper and lower central incisors to each other.

•It is a measure of the •degree of procumbency

•of the incisor teeth.•The mean value :

•135.7O with a range •from 130O to 150.5O .

•Mansoura measurements :•Male : 122.8O 12O.

•female : 122O 8.6O.•Mean : 122O 1.8O.

•If angle smaller than normal this indicates :-•Class I bimaxillary protrusion in which fullness of the lips are seen, and both the teeth and alveolar

bones are too far forward from the denture bases.In BlacK races, this biprotrusion is normal.

•Class II division I malocclusion.

If angle larger than normal this indicates :-Class II division 2 malocclusion which associated with deep anterior over bite because there is no ( incisal stop ) to prevent supra eruption of the incisors.

Therefore, in cases of deep anterior over bite, not only is it important to correct the vertical problem, but it is also important to treat the incisors to a proper inter incisal angle to prevent its relaps.In biretrusion cases, the incisors are up right, in those patient dished in faces are seen.

•Lower incisor to Occlusal plane :- ( T to OP )•This angle indicates the inclination of the lower central incisor in relation to the Occlusal plane.

•The angle measured is the inferior inside angle ( the complement of the angle formed by the inter

section of the long axis of T with the Occlusal plane.

Mean value : 14.5O with a range from 3.5O to 20O .This angle is larger than normal in class II division 1 and smaller than normal in class III malocclusion.

•Lower incisor to mandibular plane :- ( T to MP )•This angle reveals the inclination of the loser central incisor in relation to the mandibular plane.The mean value : 91.4O or 90O, the difference in the mean is duo to the slightly different methods of locating the mandibular plane. ( 90O 5O ).

•All previous studies have located the mandibular plane tangent to the lower border of the

mandibular at gonion and the lowest anterior point which usually is found beneath the

premolars.

•As the latter point is not in the midline and appositional growth occure in this area, the

lowest point of the mandible in the mid sagittal plane (menton) is used as the anterior tangant

point ,by down’s .(Go-Me).

As the relationship of the lower incisors to the mandibular plane is a right angle (90) so the labial tip of the incisors is described as plus the number degrees in excess of 90.

Mansoura measurements:-Male: 101.6 ±8Female: 97.7 ±7Mean 100.1 ± 7.8

Upper incisors to Apo line :-(The protrusion of the maxillary) incisors is measured as the distance between the incisal edge of the maxillary central incisor to the line from point A-pogonion. This distance is positive if the incisal edge is ahead of the point A-pogonion line and indicates the amount of maxillary dental protrusion.

The reading is negative if the incisal edge lies behind the point A-pogonion line and suggests a retruded position of maxillary incisors.The minimal reading is —1.0 mm; the maximal, +5 mm; and the mean, +2.7 mm.

Tweed's analysis :-•In order to study the human dentition, Tweed

selected one hundred patients of both sexes and various age groups with normal, healthy occlusions

of the permanent dentition which are esthetically pleasing.

Tweed's triangle :-•It is formed by the Frankfort horizontal

plane, mandibular plane and a line drawn through the long axis of the most protrusive

lower incisor.

•The Frankfort mandibular incisor angle ( FMIA ) : is formed by the Frankfort plane and the line drawn

through the long axis of the mandibular incisor.•Tweed's belief that the ideal relationship of the

lower to the Frankfort plane should give an angle of 65O .

•Any reading below 65O indicates a procumbency of the lower incisors to basal bone.•Any reading above 65O indicates a lingual axial relationship of the mandibular incisors to basal bone.•The mandibular incisor plane angle ( IMPA ) : is formed by mandibular plane and line drawn through the long axis of the loser incisor.According to Tweed this angle should measure 90O 5O, depending on the Frankfort mandibular angle.

•With a short ramus and an obtuse gonialongle the IMPA may read below 90O .

•While in squared jaw individuals, the angle may read above 90O .

•Tweed's triangle :- ( The requirements )harmonious face with normal occlusion requires :-

ANB angle : not exceeds 4.5O .FMIA : 65O .

IMPA : 90O ( 5O .FMA : 20O – 30O .

•By using the Tweed's triangle, Tweed assessed the linear arch length. To determine if extraction of teeth is needed or

not during treatment of the malocclusion.•Eacth tooth anterior to the first molar is measured with a

caliper. This called the required space.•The linear measurement of the arch from the mesial surface of the first molar of one side to the missal surface of the first

molar of the other side is called the available space.

The incisal reduction ( IR ) :-•A line drawn from the apex of the most

procumbent lower incisor to a point 65O on the Frankfort plane is Known as the incisal Reduction

( IR ).This designates the true position of the basal bone.

•When the line falls lingual to the mandibular incisor, the reading is a minus and indicates the lower teeth

are in procumbent relationship to the basal bone.

•Conversely, when the IR line lies labial to the lower incisors, the reading is a plus and indicates : the

mandibular incisors are in a lingual axial relationship to basal bone.

•The IR number must be multiplied by 2 because the mandible is eliptical in shape. and must be

considered geometrically.

•The mass tooth discrepancy : is determined from the figures which represents the available space,

Required space, and the incisal reduction.•Any minus reading indicates the need for

extraction. The prognosis for the facial balance and harmony is depend on the FMA.

•Any reading 35O is considered favorable, while any reading above 35O presents a poor profile with an

unfavorable prognosis.

Tweed's objectives :-•The best balance and harmony of facial

lines ( facial esthetics ).•Stability of the denture after treatment

( permanency of result ).•Healthy mouth tissues ( longevity of

dentition ).•An efficient chewing mechanism.

Tweed's formula for treatment :-•Non. Extraction – FMIA 65O or greater with sufficient

arch length.•Border line – FMIA 62O to 65O and sufficient arch

length.•Extraction –FMIA 62O or less.

•The lower incisor should be oriented to give a pleasing face and this determines whether or not

extraction is to be made.

•Harmony of Tweed's clinical findings :( balanced and harmony ) :-•FMA : from 16O to 28O progonosis from excellent to good.•FMA : from 28O to 32O progonosis from good to fair.•FMA : from 32O to 35O progonosis from fair to favorable.•FMA : from 35O to anything upward progonosis gets lees favorable.FMA : of 45O and above progonosis is nill.

•Determining the tooth mass discrepancy :-( All measurements are made in the mandible ) :-

•1- Available space :- The linear measurement from the mesial of the

first molar on one side to the mesial of the first molar on the opposite side is measured with a

brass wire.

The wire is easy contoured so that it runs along the buccal cusps of the premolars and the incisal edges of the anterior teeth as far

labially as the most protrusive incisor. This wire is laid along a millimeter ruler

and the measurement is recorded.

•2 - The IR or incisal reduction :- This is determined cephalometrically by dropping

a line from the FH at a 65O angle to the apex of the lower central incisor. It is done to establish the true

position of the basal bone as it is related to the linear measurement of the available space.

•If the line falls lingual to the lower incisor, or if FMIA less than 65O, the IR must be a minus reading.

•If the IR line lies labial to the lower incisor, or if FMIA greater than 65O, IR must be plus.

•IR measurement must be multiplied by 2 duo to the elliptical shape of the mandible. ( either + or - ).

3- Correcting the available space :- The IR measurement is either add or subtracted from the previous available space obtained with the brass wire. This will correct any labial or lingual deviation of the lower incisors from the true basal bone.

•4- The required space :- The sum total of the mesio-distal widths of each

tooth mesial to the first molars. This will include the four premolars, two cuspids,

two laterals and two centrals. It can be done with the aid of caliper using the

patient's models to measure the erupted permanent teeth and intra oral xrays can be used to measure the

un erupted permanent teeth.

•5- If the required space is lees than the corrected available space :- The tooth mass discrepancy is recorded as a plus figure.•When the required space is greater than the corrected available space: the tooth mass discrepancy is recorded as a minus figure.A minus tooth mass discrepancy indicates a lack of the clinical linear measurement.

•Tweed analysis :- N.B :•A cephalometric evaluation can not be considered

complete without including the soft-tissue facial contours, and racial differences.

•A patient's profile may affect the decision to need to extract or not.

•When one has a well developed nose or chine, the extraction may be contra indicated, because he was

wind up with a dished in appearance if teeth would be extracted.

•Person that is fleshy and round faced may look well with a bimaxillary protrusion.

Ricketts analysis•Ricketts established live minimum

cephalometric measurements :-•1-Facial angle :-

As established by Down's the superior border of the extranal auditory canal is

used in constructing the FH.

The mean is 85.4O 3.7O . One degree represents 1.5 mm of difference in

position of the chine. Relative to the nasion point.•Facial angle 80O are retrognathic.•Facial angle 85O are orthognathic

•Facial angle 90O are prognathic

•2- X – Y axis :- ( Facial axis )•A line from sella to gnathion.

•X – y axis is an indicator of the facial height.•This is measured where the x – y axis crosses the

nasion – basion line.

•A differenc of one degree represents a lmost 2 mm of height relative to depth.

•The average angle is 93O or plus 3O.•The rang of variation is from – 12O to 29O with a

standard deviation of 3O .

•This suggests that x-y measurement less than zero tend towards greater length in facial from as opposed to

depth.•The x-y axis is considerd plus if it is more than 90O and

minus if it is less than 90O those with less than 90O are retrognathic.

•3- Maxillary incisors to A.point – pogonion line :-•The A point – pogonion line is an indicator of denture

position in relation to the facial line.•This is 5.7 mm with arrange

• from -8 mm to 15 mm.•One standard deviation is

• the equivalent of 3 mm.

•4-Mandibular incisors to A. point – pogonion line :-•The average mandibular

• incisor tip is located •approximately 0.5mm

•arterior to the A. pog line• one standard deviation is

• 2.7 mm.•The rang of variation is

•between + 10 mm and – 10 mm.

•The mandibular incisors •inclines on an average 20.5O

•to the line A- pog.

•One standard deviation of inclination is 6.4O .•The range of angulations is from -11O to + 53O the

range of standard deviation is 15O to 27O .•Mansoura measurements :-

•Male : 4.35 3 mm.•Female : 4.06 2 mm.

•Total : 4.24 3 mm.

Facial contour :-•This is A. point related to the facial line.

•It is used to determine the relationship of the maxilla to the mandible as seen in the bony profile.

•At the usual distance from nasion to A.point 1

degree of difference from the line N.A to the facial line equals about 1 mm

on an arc from A. point to the facial line.

•There fore direct measurement from A.point to the facial line is used to measure variation of the profile a straight line.

•A reading of 10 mm distance from A.point to the facial line is about 20O of convexity as

measured by Downs, or about half that of the angular value

in millimeters.•There is an average of 4.1 mm

• and a standard deviation of 2.8 •mm.

•Faces with a convexity or concavity of not more than 2 mm are regarded as being orthognathic.

•Those with up to 5 or 6 mm convexity or concavity are classified as moderately

• convex or concave.•At, 10 mm or over, the faces

• are severely convex or• concave.

•Facial esthetic line ( E- line ) :-

•The facial esthetic line extends from the tip of the

nose to the end of the chin.•These measurements

indicate the antero-posterior position of the lips with

reference to the line between the most anterior point of the soft-tissue chine ( pogonion )

and the most anterior point of the nose ( pro nasale ) .

•The lower lip is on an average 0.3 forward to this

line with a standard of 3 mm.

•The upper lip is on an average 1 mm posterior to

the lower lip when related to the facial esthetic line.•The mean is – 7 mm.

At age of 11 to 14 years there is an average practically no variation of the lower lip to the facial esthetic line. In adults the difference is -4 mm.

•Mansoura measurements :-•Male : upper lip : -2.23 1.96 mm.

Lower lip : -0.12 2.7 mm.•Female: upper lip : -5.2 2.1 mm.

Lower lip : -1.44 2.8 mm.•Total : upper lip : -3.4 2.45 mm.

Lower lip : -0.62 2.75 mm.

•This reference line describes facial esthetics

and lip position.•Dentures that are forward

( class I bimaxillary protrusion and, class II

division 1 malocclusion ) produce a convex profile with the lips ahead of the

E-line.•Straight or concave

profiles ( class II division 2, and class III ) are

associated with returned lips.

•Larger noses or large chin buttons or combination of the

two cases produce erroneous measurements of

the lips to the E- lone.•In such cases, a rhino

plasty or genioplasty may be necessary in order to arrive

at a pleasing profile.

Sassouni's analysis•In order to study the stracture of the skull for the

purpose of growth analysis and treatment, Sassouni constructed planes, arcs and axes on the lateral

cephalogram.

•From these planes he determines the centre, and then he uses the reference 0, after analysis of these planes, the problem becaomes obvious to you. This

analysis is individual in nature and is not proportional but translates the anomaly in millimeter.

.

•Steps of the analysis :-•1- Construction of the planes.

•2- Locate the centre O.•3- Construction of the arcs.•4- Construction of the axes.•5- Evaluation of the profile.

A- Construction of the planes.

1- Anterior cranial base planer or Basal plane ( OS ) :-

Two parts, first draw a tangent from the anterior clinoid to the superior part of the roof of the orbit which

called the : cranial base plane and second draw a plane parallet to the first one and tangent to the

inferior border of the sella turcica and called : the supra orbital plane.

•2- Palatal plane ( ON ) :- It is perpendicular to the midsagittal plane, going through

the anterior nasal spine ( ANS ) and the posterior nasal spine ( PNS ) and extended posteriorly as you can.

•3- Occlusal plane ( OP ) :- Similar to Downs. ( Midpoint of incisor over bite through

the incisal edges of the upper and the lower central incisors, and cusp height through the mesial cusps of the permanent

upper and lower first molars.In open bite ignare the incisors and use the posterior teeth only. In deep over bite ( deep curve of spee ) take the occlusal surfaces of the molars and premolars do not use the incisors.

• In deep over bite ( deep curve of spee ) take the occlusal surfaces of the molars and premolars do not

use the incisors.

•4- Mandibular plane ( OG ) :- Of Down's, from ME-tangent to the lower border of

the mandibular body.•5- Ramus plane ( RX ) :-

The plane runs tangent to the posterior border of the ascending ramus.

B- Locate the centre O.To locate the centre O make sure when you put the tracing paper on the film that you are taking the lesser amount of soft tissue profile and extend the planes posteriorly as you can. Also look at the posterior area, if you have any doubt to find this area, locate the two extreme planes i.e take the most divergent two planes and draw a vertical lines, the lines will decrease in length and the increase gradually.

O is the centre or the midpoint of the shortest vertical line beyond which the planes will diverage.

O will located up in cases of :(1)Skeletal open bite.

(2)Deep bite. Ignore any bizarre plane, in this case take the

other three planes.

C- Construction of the arcs.a - For the antero-posterior

dimension :-1- Anterior arc.

2- Basal arc.3 - Mid facial arc.4 - Posterior arc.

1- Anterior arc.The anterior arc is the arc of a circle, between the anterior cranial base plane and the mandibular plane, with O as centre and O-ANS as radius. Use the centre O, as the one end of the compass, and open it until the N and draw an arc that pog and ANS posterior to this arc draw another arc because N may be too forward. If you find pog and ANS too forward to this arc draw another arc with ANS as radius i.e spinal arc.

•2- Basal arc :- Using the centre O to point A as a radius and draw another arc but if ANS is closer to the anterior arc than the pog, take the ANS as a radius from the centre O.•3- Mid facial arc :- Using the centre O to temporali, draw an arc down to the occlusal plane. Temporali (Te ) is the intersection of the shadows of the ethmoid and anterior wall of the infratemporal fossa.

4- Posterior arc :- Between the anterior cranial base plane and the mandibular plane, of a circle with its centre

at O and OSA as ( SA is the most posterior point on the rear margin of sella turcica ) posterior arc from O to the centre of the contour of sella as a

radius.

b -Arcs for the vertical dimensions :-•1- From as a centre to supra orbitale ( eye brow ) as

a radius make a small arc and then rotate the compass downward and draw another arc down.In adult patient draw a second small arc 10 mm

below the first one, both are below the chin.•2- Posteriorly from PNS as a centre and the point of inter section of the parallel to plane (1) and posterior

arc draw (2) arcs up and down.

•In deep bite : you will find parallel planes and centre O will shift away from the profile.

•In open bite : steeper planes and centre O is very close to the profile.

•In class II skeletal cases, centre O is lower.•In class III cases, it is higher relative to foramen

magnum.

•Evaluation of the profile :-•1- From the anterior arc :-

Evaluate the labial surface the maxillary incisors pogonion and ANS.

•A- In well balanced face all these points are on the anterior arc.

If you find ANS and pogonion are anterior to this arc by equal amount this situation considers normal.

•B- If you find ANS and pog equal distance too forward or too backward this is normal.

•C- ANS on the arc and pogonion is not on the arc :

•1- ANS on the arc and pog anterior to the arc this means chin protusion.

•2- ANS on the arc and pogonion posterior to the arc this means mandibular retrusion.

•D- Combination if pog is on the arc, ANS could be anterior or posterior.

•2- From the basal arc :- Normally from A will pass through point B or

approximating this area.•3- From mid facial arc :-

Evaluate the maxillary first molar, the mesial contour of the first molar should be tangent to this

arc. In the mixed dentition the first mnolar will be 2

mm distal to the arc because of the lee way space.

•4- Posterior arc :- Normally it passes through the gonion

and indicates either the chin is protrusive or retrusive.

In well balanced face the corpus size is equal to the cranial size i.e from the anterior

are the posterior arc.

•The vertical balance :- The outer upper and lower facial height

should be equal in adult male, the lower face height is larger 6-7 mm than the upper.

The distance from N to the inter section of the anterior arc with the first plane should be added to the lower face height from menton.

In posterior vertical height the upper posterior and lower posterior heights should

be equal i.e the upper posterior and lower posterior parts of the arc should be equal.

•Limitation :- With this analysis you have to dissociate

between the soft-tissue and the skeletal reading in class II skeletal with open bite on

the other hand it correlates well with class III.

•Axes :-•M, M', M ً Axis of –6 •m, m' Axis of –6•I, I', I ً Axis of •I, I' Axis of T

•The Sassouni norm :- In a well-proportioned face the four planes :-

•1- that tangent to the sella and parallel with anterior cranial base, (2) the palatal plane, (3) the occlusal

plane, and (4) the mandibular plane, meet at O.•2- while an arc from O to the anterior nasal spine

( ANS ) as a radius, will pass also through the pogonion, the incisal edge of the maxillary central

incisor, the nasion, and the frontoethmoid junction.

•3- If a circle has centre O, an arc that passes through the posterior wall of the sella turcica will

pass also through the gonion.•A dysplasia in any one part of the face is reflected in

the face as a whole.•4- The relation of the four planes to the commen

point, O, permits the classification of four facial types :-

Type1: anterior cranial base plane does not pass through O.

TypeII: palatal plane does not pass through O.Type III: Occlusal plane does not pass through O.

Type IIII: Mandibu for base plane does not pass through O.

•The axial relation of the maxillary and mandibular teeth to the maxillary and

mandibular teeth to the palatal plane and mandibular plane such that:

•Angle M = angle I + 10.•Angle M = angle I + 5.

•The angle formed by the ramal plane with the occlusal plane ® is equal to the angle

formed by the inc lination of the mandibular centralincisor and the occlusal plane (I)

(angle R = angle I).

•Since the norm concept can not be accepted as absolute for the individual,

Sassouni advocales measure ment of proportionality in the individual as a base

for growth study, diagnosis, and treatment planning.

•N.B: discrepancy within 1 – 2 mm by archival analysis considers normal.

•Steiner's analysis (1953)•1- SNA angle:

•Used by riedel in 1950 and •then Steiner in 1953.

•It provides in formation• of the anteroposterior

•position of the apical •base of the maxilla •either protruded or

• retruded to the anterior• cranial base.

•Mean value is 81 sd 3.

•If it greater than 80, it indicates protrusion of

the maxilla (skeletal class II mal occlusion).

•If lt less than 80, it indicates retrusion of the maxilla (skeletal class III

malocclusion).•This is describing the

position nothing regarding the size.

•This angle influenced by antero postemrior

position and also bertical position of

nasion.•If nasion is more

forward, higher, lower or backward, this will influence the value of

the angle.

Age change:•This angle imdergpesminor age changes, there is proportional growth between the maxilla and anterior cranial base, it has to stay constant.•Mansoura measurements: Male: 82.15 + 2.8 female: 80.69 + 2.5.Mean: 81.6 + 2.8.

2- SNB angle:•It provide information of the antero posterior position of the apical base of the mandible either protruded or retruded to anterior cranial base.The mean value is 78 with sd ± 3

•If the angle is smaller than normal (class II)

malocclusion that is caused by a

retrognathic mandible).•If the angle is greater than normal (class III

malocclusion duo to a prognathic mandible).

•It is influenced by antero posterior and

vertical position of the nasion.

Age changes:•This angle increase with

age, because the mand ible grows more than the

maxilla, and the growth is in horizontal direction.

•Mansoura measurements:Male: 79.69 + 2.4.

female: 77.8 + 3.29.Mean: 78.9 + 3..

3- ANB angle :-•It is the difference between SNA and SNB agles.•It indicates the antero-posterior position of the maxillary apical base relative to the mandibular apical base.•The mean value is 6 + 3.

If the value is larger than the mean, this means that maxillary protrusion or mandibular retrusion, but it will not tell you where the maxilla is forward and where the mandible is back ward. (class II skeletal malooclusion).

•If the value is smaller than the mean, this means that

maxillary retrusion or mandibular protrusion

(class III skeletal malocclusion). But it does

not tell you which one is wrong.

Mansoura measurements:Male:205 + 1.8.

female: 2.88 + 1.09.Mean: 2.46 + 1.53.

Factors affecting the values of SNA, SNB and ANB. Angles:

(a) Size of the anterior crania base if it is large or small this will change the angulation.(b) Position of nasion, higher or lower.

(c) Maxilla and mandible in relation to position are bar word or back word or rotated in a slight

The method of Richard reidal:(1)Because the points S and N are both located in hard, nonyielding tissue, are directly and easily visible in a profile x-

ray picture, and particularly because they one located in the midsagittal plane

and there for are displaced to a minimum degree by movement of the

head, the SN line was chosen as a reference line for all of the assessment

measurements.

4- SND angle:(1)Point d: the middle of the symphysis. It is used to represent the anterior aspect of the

mandible in a sagittal plane.(2)Point D can be

established on the mandible to serve asequivalent purpose.

(3) The cross section of the body of the mandible is

only considered.(1)Alveolar process is ignored because it is

influenced by the positions of the teeth and is

changeable. Either visually or with instrument,

establish a poing at the centre of the mass of this cross section. It is called

point D, like point sin in the cranium.

It is well surrounded by sturdy done, it is protected from

outside influences and is well isolated from the area where

movement of the teeth and normal grow the changes

occur. The SND angle is used to esprss and evaluate the

antero posterior location of the anterior portion of the

mandible in relation to the head as whole.

SND will record the changes more accurately than when

using the angles SNB or SNB og.

Point D can also be used to determine chnges, in the

position of the mandibular teeth within the mandible. To do so, erect a line through D

perpendicular to the line Go – Gn. To a position even with the incisal edge of the lower

incisor (d- line).Generally D – line will pass

through the lower central incisor but the varied

relationship of this totth to this D- line will be a surprise.

D point is sued as a reference point, and is transferred to

subsequent tracings by coping it directly from the first.

Copy the line go – gn and the point D from the first to the

subsequent tracing.The line go – gn and poing D will serve the same purposes for the

moving mandible, as does the line SN and the poing N for the

rest of the skull. When the mandible moves, line go-gn and

point D move with it.

Denture criteria:Upper incisor to NA: (linear).•The upper incisor should lie on the line NA in such a way that the most mesially placed point on its crown is 4 mm in front of the line NA.This measurement indicates the interpose.

•Rior position of the incisal edge ot he upper

central incisor, with reference to the NA line.•The clinician can decide

whether the incisor has to be protruded or

retruded by tipping mechanics, bodily

movement, or by a combination of the two

procedures.

•This angle indicates the inclination of the upper

central incisor. •The axial inclination of to

NA line is 22.•It is preferred to use NA

line instead of facial plane because NA is

established by two fixed points plane because NA

is established by two fixed pints one of them on the

maxilla and in juxta position to the tooth in

question.

Upper incisor to NA:

•It is preferred to use NA line instead of facial plane

because NA is established by two fixed points plane

because NA is established by two fixed pints one of them on

the maxilla and in juxta position to the tooth in

question. In contrast the facial plane is depedent on a

changeable moving part.•The chin point pogonion).

•A larger than normal angel, is seen in class II division I

mal occlusion.

•Clinically, this angle is important in torgue control when retracting or advancing upper incisors.

Mansoura measurements:(1)to NA (linear): male: 5.81 mm + 3.77 mm.

female: 5.31 mm + 0.59 mm.mean: 5.26 mm + 2.95 mm.

(1)to NA (angle(: male: 24.69 + 7.72.femal: 24.88 + 2.84.mean: 24.78 + 6.21.

Lower incisor to NB: (angle):•This angle reveals the •inclination of the lower• central incisor. •The axial inclination of •the I to the NB line is 25.•This angle is larger than• normal in a class II •division I malocclusion.•This angle is smaller than• normal in skeletal class III malocclusion.•Mansoura measurements:•Male: 29.45 + 6.35.Mean: 29.62 + 6.1.

Lower incisor to NB (linear):

•This measurement gives an idivation of the antero-

posterior linear measurement of the lower central incisor

with refrence to the NB line.•The most mesial point on the crown of the t is 4 mm in front

of the line NB.

•This measurement is larger than normal, (protrusive or in

positive direction) in malocclusions associated with

a convex profile. (class I bimaxillary protrusion and class

II division 1).•And larger in a negative

direction (retrusive) in mal occlusions associated with a

straight or concave profile (class II division 2 or class III).

•Male: 7.35 + 2.69 mm.•Female: 6.91 + 1.44 mm.

•Mean: 6.90 + 2.25 mm.

Pogonion to NB (linear):•The degree of prominence

of the chin should contribute to a determination of the

placement of the lower.There fore, the method of

holdaway is followed and the distance is

measured from pogonion (pog) the line NB.

•This distance will vary so wide by among individuals that an

average or norm measurement of it would have little diagnostic

value. Because the chin point varies according to type in off

individuals so the difference between the two

measurements T to NB and pog to NB will vary widely

among normal individuals.•Holdaways liked this distances

to be equal.

•He beleives that the overlying soft tissues one of average

thickness and arrangement, acceptable results can be

obtained when these measurements vary within a range of 2 mm. he regards a

3mm variance is being tolerated.•The ratio between these two measurements can be greatly

influenced by orthodontic therapy and it can be brought

within acceptable limits.

•This measurement indicates the amount of bony chin

buttons present in the symphysis of the mandible.

•Clinically, this measurement dictates the anterior

positioning of the lower incisor during treatment.

•An in sufficient bony chin contributes to a convex skeletal profile, thereby

necessitating retraction of the lower incisor to improve the

esthetics.

•A good chin enhances the profile and allows a more labial placement of the lower incisor to

prevent a dished in appearance to the lower soft – tissue profile.

•Average value is pog 4 mm in front NB line.•Mansoura measurements:

•Male 7.35 + 2.65 mm.•Female: 6.81 + 2 mm.•Mean: 7.14 + 2.4 mm.

•(t – NB / pong – nb)

Inter incisal angle:This angle was illustrated in the downs analysis.

This angle used as a supplementary method

of appraisal of the angulations of these teeth (T to ┴ )

to each other and to the face.This measurement indicates

the total variation from normal of these teeth to

each other.Average value is 131.

Occlusal plane angle (occl – SN):The angle of the occlusal plane to SN (principle of downs) except that this analysis uses the SN line instead of the Frankfort horizontal plane. used by

downs.

A cephalometric survey of a case of malocclusion would be incomplete without the appraisal of the location of the teeth in occlusion to the face and to the skull.

SN to mandibular plane agnle (go. Gn To SN)"The angle go-gn to SN is very useful in:(1)Measures the degree of warpage or malformation of the mandible it self or the surfaces with Which it articulates.

(2) As an indication of the growth history. The line Go-Gn has been taken to represent the body of the

mandible ( Riesel ). A line which more nearly represents the mass of the body of the mandible rather than its lower border is preferred. ( Mean

value is 32O )

•Upper incisor to SN :-•This angle reveals the inclination of the central

incisor, as related to the cranial base line ( SN ).

•Mean value is ( 104O ) .•A larger than normal

angle indicates class II division 1 and class III

malocclusion.•A smaller than normal angle indicates class II

division 2 malocclusion.•Clinically this angle is

important torque control when retracting or

advancing upper incisors.

•Modification of Tweed- Holdaway and Steiner :-

Dr. Tweed selected 100 people of both sexes and different age groups whom he considered to have excellent facial profiles and who did not need any

orthodontic regulation. Their occlusions were considered to be normal

and healthy in every respect.

He then proceded to make a comprehensive cephalometric analysis of these patients using the

statistical data as the normal objective to be attained in evaluating a malocclusion.

In this manner he advised his 90O ( ) 5 formula.

It is his contention that the lower incisor must be upright on basal bone. This theory has been criticized in

many quarters because it is a cut and dry method in dealing with numerous complex situations which are not

accounted for.

Dr. Holdaway, who feels that Dr. Tweed's estimate has some merit, none the less claims that the relationship of the mandible to the maxilla can

not be ignored when making any sort of evaluation as to the proper axial inclination of the anterior teeth.

•1- To prove this point, he took Dr. Tweed's data of the same 100 patients and found that the ANB

varied from minus 1O to plus 5O .

•2- He then put the patients into specific groupings and found that the median normal for ANB was ( 2O ) Further study showed that long axis of the upper central to the NA line formed an angle of ( 22O ) with the incisal edge 4 mm. distant from the NA line along the occlusal plane.3- Like wise, he found that the long axis of the lower incisor to the NB line formed an angle of ( 25O ) with the incisal edge 4 mm. from the NB line along the occlusal plane.

•4- These findings challenged D. Tweed's formula. •There is no doubt that the angle ANB definitely influences the axial inclination of the upper and lower anteriors.5- The fact is, as the ANB increases, the axial inclination of the maxillary incisors decreases, while the axial inclination of the mandibular incisors increases.

•6- Proportionately, as the procumbency of the uppers diminishes, the incisal edge of the maxillary incisors lies closer to the NA line.•7- In the lower arch, as the procumbency of the incisors increases, the distance from the incisal edge to the NB line increases.8- If the ANB reading falls beyond minus 1O to plus 5O, it can be certain that an aesthetic or stable result can hardly be expected.

Dr. Steiner, has formulated what he refers to as ( the ideal acceptable Arrangements ) Rather than

be committed to a statistical median normal, it is his contention that man must have several normal

arrangements which may be considered aesthetically acceptable and stable.

In other words, all people do not fall into a rigid pattern, as Dr. Tweed contends, nor do people

necessarily have to conform to any sort of a median norm since the normal range varies to such a great

degree.All this reasoning was brought forth from the data

accumulated from Tweed's 100 cases.

•The lower line: symbolizes the long axis of the lower central as it relates to the NB line

in mm. and degrees.At an ANB of 2O, the readings are 4 mm and

25O.•As the ANB increases, the figures

representing the upper central decrease while the figures representing the lower

central increase.•The reverse is true when the ANB goes

below 2O.•

•A patient with an FMA between 15O to 35O and an ANB of -1O to +5O may be considered one that falls

within a normal range. With an ANB above 9O or below -3O, the prognosis

is poor.Should such patient have a 40O FMA or above, the

prognosis is hopeless.•When ANB increases, by 1O, to NA decreases

by 1 ( millimetric or angular ) and T to NB increases by 0.25 mm and 1O.

•When ANB decreases, by 1O, to NA increases by 1 ( millimetric or angular ) and T to NB increases by

0.25 mm and 1O.

•Michigan analysis.•SNA. ( Steiner 1953 )•SNB. ( Steiner 1953 )•ANB. ( Steiner 1953 )

•Facial angle : ( Down's 1948 )

•It is determined by drawing a line from nasion to pogonion, this plane is called the facial

plane. The inferior inside angle of its intersection with

the FH is the facial angle.

•Downs used FH as a reference plane because it gives him the natural position of the head in

determining this angle.•There is one factor which affect this angle which

is the morphology of the symphysis :-•(1) Long and narrow, in this condition there is no

difference between B point and pogonion.

2- Button like chin, and in assessing SNB in a case you may find its value indicates a class II but facial angle tells you it is class III duo to the button

like symphysis.3- Short and broad chin.

•Age changes :-If you have a child syears old and shows some

tendency toward larger Facial angle, it will becomes larger and, the larger. So if you have a

class II at syears, the profile of this patient is improving because of the growth of the mandible.

This angle tests the SNB. And gives some verification.

•Angle of convexity ( Down's ) :-•A-B to facial plane angle ( Down's ) .

•A-B to occlusal plane : ( Bushra 1974 )•It measures the relative position of point A

and B to occlusal plane.•If B point is forward the inferior posterior

angle formed by A-B line and occlusal plane is increased than 90O which is the mean.

•If point B more backward, the angle is decreased.

•Mansoura measurements :-Male : 0.96 ( ) 2.25 mm.

Female : 0.94 3 ( ) 3.22 mm.Mean : 0.24 ( ) 2.75 mm.

There are two types the occlusal plane :-•(1) Functional occlusal plane :-

Which is formed by bisecting cusp heights of molars and bicuspids, but not the incisors. Because in open bite and

deep over bite cases the anatomical occlusal plane is distorted.

(2) Anatomical occlusal plane :-Formed by bisecting the incisor overbite and cusp height of the molars.

•Wits appraisal ( Jacobson 1975 ) :-

The wits appraisal of jaw disharmony is a measure of

the extend to which the jaws are related to each other

antero posteriorly .•It entails drawing

perpendiculars on a lateral tracing from points A and B

on the maxilla and mandible respectively onto the

occlusal plane which is the functional occlusal plane.

•The points of contact on the occlusal plane are labeled Ao and

Bo.•The normal value : for

Female, is 0 i.e Ao and Bo concided ( ) 2.

: for male, -1 to -2 point b forward.If Bo is anterior to Ao, the value will

be negative.If Bo is posterior to Ao, the value

will be positive.Wits eliminates the problem of

SN either too forward or too backward so it assess points A

and B.

•SN. To Mandibular plane :- ( Steiner ) It is formed by intersection of the SN line with the

mandibular plane.•There are two basic mandibular plane :-

•(1) From menton to just behind the antegonial notch tangent to the lower border of the mandible.

• ( Down's and Tweed ).

•From Go-Gn ( Steiner ) :-•The angle formed by SN and mandibular plane provides information in vertical and

antero posterior dimensions. i.e the lower half of the face and position of the chine.

•In flat mandibular plane angle ( smaller angle ) :-

oPNS could be normal or tipped up ward.

oThe gonial angle is acute.oThe condyle is lower in position.

•In higher or steep mandibular plane angle ( larger angle ) :-

oRamus is short, corpus is short i.e oral size of the mandible is short.

oThe gonial angle is obtuse.oThe condyle is very high relative to

the sella turcica.

•Clinically :-•(1) Patients with higher or steep mandibular plane angle : have – Large lower face height

– Retrusive chin.•Steep mandibular plane is usually associated with class II open bite.

•Higher steep mandibular plane is not related to the prognosis of the case because you

many find a case nice looking and has only steep mandibular plane.

2- Patients with flat mandibular plane angle : have – The posterior facial height is smaller than the

anterior lower face height or equal to it – forward position of the chine.

•There is a negative correlation between the facial angle and mandibular plane.

If the facial angle is large, the mandibular plane will be flat.

If it is small, the plane will be steep.Mansoura measurements :-

Male : 29O ( ) 6.07O.Female : 33.75O ( ) 4.3O.Mean : 30.81O ( ) 5.84O.

•SN to palatal plane angle•It gives information regarding position of ANS, PNS

or rotation of the plate. PNS may be tipped up or down relative to ANS. i.e in clockwise or counter

clock wise direction.

•If you have smaller angle : this means that there is no displacement of PNS down ward in

counter clock wise direction.•This will decrease the anterior lower face

height.

•If the angle is greater than 8O : this means that the ANS tipped down ward and this is

associated with large anterior facial height.•In normal subjects palatal plane will pass

through the odontoid process and basion this gives a very good clue regarding the

displacement of PNS.•Mansoura measurements :-Male : 9.19O ( ) 3.4O.

Female : 11.25O ( ) 5.12O.Mean : 9.98O ( ) 4.15O.

•Palatal plane to Mandibular plane :-( used in 1936 by Schwarz and picked up by

Sassouni ).•It can figures if there is something wrong regarding

SN or palatal plane.•Large angle indicates :

Steep mandibular plane. or PNS tipped down ward or both.

•It is usually associated with large anterior facial height, and small posterior facial height.

•Large angle suggest open bite or class II.•Mansoura measurements :-

Male : 20.27O ( ) 6.37O.Female : 22.88O ( ) 5.4O.

Mean : 21.26O ( ) 6.03O.

•Cranial base angle :-( used by Pjork 1947 and Ricketts )•It is formed by 2 lines SN and SBa.•It denotes the of glenoid fossa and TMj and someinformation regardingmalocclusion.

You are measuring the angle in midsagittal plane but the glenoid fossa is bilaterally positioned so it may implied for the synchronized growth in the midsagittal and lateral directions. In obtuse angle cases : The mandible is carried backward which reflects chin backward.

•In acute angle cases : TMJ will be forward and the mandible is carried forward creating class III or protrusive mandible.•Even if the mandible has normal shape and size it may has different position if cranial base angle is large or small.•Mansoura measurements :-

Male : 147.12O ( ) 9.6O.Female : 148.5O ( ) 6.2O.Mean : 147.6O ( ) 8.5O.

•Frankfort horizontal to mandible Plane angle :-

( Tweed 1946 and Down ).•It is very similar in information gained by SN

to mandibular plane.

•Facial axis ( Ricketts ) :-•It is constructed of Na – Ba and gnathion – foramen – rotundum.•It is an expression of growth in the horizontal and vertical direction of the• face.•Large values will have• more or less skeletal• problems.

•If the chin is too forward, you will have large value, if it is too posterior, you will have small value.It is very similar to Down's Y axis.

•It gives information regarding the downward and forward growth direction during development.

•If you have equal horizontal growth to vertical growth, the angle will be 90O.

If the vertical growth exceeds the horizontal growth, the angle is decreased.

If the angle is larger, this denotes that the growth is in horizontal direction.

•Try to relate facial axis with the facial angle, facial axis alone gives the

position of the chine only.

•Posterior facial height to anterior facial height :-

•The mean value is 65 % ( it is the percentage of S- Go to Na-Me ).

•Smaller values, are associated with skeletal open bite, this denotes that anterior facial

height is large and posterior facial height is smaller.

•You can use SN palatal plane or Mand. plane to palatal plane because the latter angle give

the same things.

•Lower anterior face height to total pace height :-•The mean value of ( ANS - Me to Na - Me ) is 54.6 % .

•Larger values tends to reflects skeletal open bite.You have to correlate with the bizygomatic width to see

either it matches or exceptible wide face with large lower facial height and the face looks good so this is

compatible.

Aging reduced lower facial height and persons with low anterior facial height aged

early.•At 6 years in males and females th upper

face height and lower anterior face height are equal in length.

•At 12 years, in females the 2 dimensions are equal, but in males the lower anterior face

height is 3 mm longer than the upper anterior one.

•In adult age, lower anterior face height in female is 3 mm longer than the upper one and

in males 7.10 mm longer than the upper.

•T to Mandibular plane ( IMPA ) :- ( Tweed )•It relates the axial inclination of the most labial incisor to the mandibular plane.•It depends on the morphology of the mandible and the mandibular plane.•If the mandibular plane is small or flat, the angle will be small.If the mandibular plane is steep, the angle will be large.

•In class III the lower incisors are lingually inclined and the mandibular plane is small and mandibular plane is flat, and IMPA smaller than 90O, this is very important in performing surgery for the mandible, the cause of the lingual inclination of the incisors in class III is the pressure of the lower lip because in this case there is no toughie pressure on these teeth.•Mansoura measurements :-

Male : 101.65O ( ) 8.1O.Female : 97.75O ( ) 7.2O.

Mean : 100.17O ( ) 7.8O.

•T to FH ( FMIA ) :- ( Tweed )•It express lower incisor to bony profile, the

average is 65O.•If IMPA is large, FMIA will be smaller and

vise versa.IMPA, FMIA and MPA form the Tweed

triangle.•Lower incisors upright with age, IMPA will

decrease, FMIA will increase.

•So when we see crowding the reason may be either duo to improper angulation by

orthodontic treatment or duo to late growth changes.

•Mansoura measurements :-Male : 55.15O ( ) 5.8O.Female : 55.3O ( ) 5.75O.

Mean : 55.21O ( ) 5.66O.

•T to ( Down's )•T to NA ( Steiner )•It relates the to denture base either angular or linear.•T to NB ( Steiner ) :-•This angle checks the procumbency of T relative to the denture base.•The average is 25O and 4 mm.•The distance in mm will decrease with age duo to righting of the incisors from 6 – 12 years of age.The angle will increase from 6 – 12 years duo to labial eruption of permanent incisors.

•Holdaway ratio ( 1956 ) :-•It relates the perpendicular distance from NB

to tip of T and the distance from NB line to pogonion.

In the average these two distance are equal i.e there is a 1 : 1 ratio.

•If this ratio is available or favorable before orthodontic treatment and at the same time

there is excessive curve of spee. this ratio will not be maintained either during or after

orthodontic treatment duo to leveling of the curve of spee. and more arch length is added.

•If you want to maintain their position, you have to find a space for this increase in arch

length.

Soft – tissue :-•Z- angle ( Merrifield 1966 ) :-

Connection between the most prominent point on soft- tissue chin and the most prominent lip

either upper or lower will form a line. Connection between

this line and FH plane result in Z angle, it

does not till you which lip is protrusive or which

lip is retrusive.

•E- plane ( Ricketts ) :- A line between the lip of the nose and the most prominent point on the soft- tissue chin

and determines the positions of the upper and the lower lips to this plane.

In balanced faces the lower lips slightly anterior and the upper lip slightly posterior to

this plane.

•Profile analysis :- Dr. Witzky : evaluate the profile according to the B-point, if it is retrognathic, mesognathic, or thognathic and evaluate it either convex, straight or concave. according to the position of soft- tissue A-point. Dr. Berger : Drop a vertical plane from soft- tissue nasion to soft- tissue pogonion perpendicular on FH and evaluate the profile if it is convex, straight or concave.

•Measurements of the soft- tissue.•Z- angle ( Merrifield 1966 ) :-

It is the inferior angle formed by the intersection of Frankfort horizontal plane and the profile line, a line tangent

to the most anterior point of the soft tissue chin and the most anterior point of either the upper or lower lip which ever was

protruding. •Mansoura measurements :-

•Male : 68.96O ( ) 6.62O.•Female : 63.88O ( ) 8.18O.

•Mean : 67.02O ( ) 7.49O.

•Angle of convexity ( N َ - pn - pog َ ) :- This measurement gives an indication of the convexity or

concavity of the soft- tissue profile with the nose included.•Mansoura measurements :-Male : 128.19O ( ) 7.18O.

Female : 128.81O ( ) 4.2O.Mean : 128.43O ( ) 6.12O.•Because this measurement is

• directly affected by mandibular •growth, retrognathism ( class II• division 1 ) is associated with

•a convex soft- tissue profile.

•Unlike the skeletal profile, the soft- tissue profile with the nose included becomes more

convex with age. This is attributed to grater forward growth of the nose than the

mandible.•An extremely small ( N َ - pn - pog َ ) angle

may indicate a need for rhinoplasty or genioplasty concomitant with orthodontic

treatment.•Average value : 135O.

•Naso- labial angle :-•It is the measurement of the protrusion of the

upper lip relative to the inferior border of the nose.•The mean value is : 106O.

•The size of the angle is very significant clinically, for example : class II division 1 cases which have

obtuse angle prior to• treatment are very

• difficult.

•If the incisor teeth are retracted in such cases the obtuseness of the angle may increase to the point of deformity and increased prominence of the nose.•Clearly such cases should be treated by holding the maxillary arch while the mandible growth forward at its inherent rate to reduce the dysplasia.•Mansoura measurements :-

Male : 100.19O ( ) 20.5O.Female : 94.88O ( ) 19.7O.

Mean : 98.17O ( ) 19.8O.

•Easthetic plane or E plane : ( Ricketts 1957 )•It is a line connecting the most anterior point on the nose ( pn ) and the most anterior point on the soft- tissue chine

( pog َ ).•The lower lip was approximately two millimeters and the

upper lip approximately four millimeters posterior to the E- line.

•Mansoura measurements :-•Upper lip : -3.36 ( ) 2.45 mm.•Lower lip : -0.62 ( ) 2.75 mm.

•Holdaway's H- angle :-•According to Holdaway there is a direct relationship between

ANB and soft- tissue profile.•H- angle is the angle between NB plane and H- line.

•H- line is drawn from the soft- tissue pogonion to the upper lip.

•He suggests that with ideal ANB angle of 2 degrees, should have a profile line

of 8O with the NB line.

•When the profile line is drawn from soft- tissue pogonion through the tip of the upper lip, it should

also intersect the nose approximately 1 cm posterior to the nose tip.

•The lower lip should be lightly touching this line.•Mansoura measurements :-

Male : 16.23O ( ) 3.4O.Female : 16.56O ( ) 1.7O.Mean : 16.36O ( ) 2.8O.

•Normal value : ( - 3.5 1 mm )•Mansoura measurements :-

Male : -1.38 1.7 mm.Female : -2.13 2.03 mm.Mean : -1.67 1.8 mm.

•Line of comper's :-•A line from the tip of ANS ( acanthion ) to the external auditory meatus.•Comper's plane :-•From tip of ANS (acanthion) to centre of external auditory meatus on right and left sides.•Comper's triangle :-•Comper's line and a line tangent to the facial profile.

•Upper lip length :-•The distance between the anterior nasal

spine ( ANS ) and the lip embrasure ( EM ).•The optimum positioning of the teeth requires

appraisal of the lip length.•A short upper lip may show too much of the

soft- tissue above the anterior teeth.•The mean value : 24 mm 2 mm .

•Mansoura measurements :-Male : 29.81 3.4 mm.Female : 27.38 3.9 mm.Mean : 28.88 3.7 mm.

•Lower lip to occlusal plane :-•The distance between the lip embrasure and the

occlusal plane.•Negative value indicate the occlusal plane is below

the lip embrasure.•A low occlusal plane indicates a short upper lip and

a gumming smile.•High occlusal plane may make the teeth appear to

be hidden.

•Components of cephalometric analysis :-•The cephalometric analysis is always made

by tracing certain bony tissue features as visualized in a lateral or postero anterior

radiograph.•When the out lines of all necessary

stractures are traced, the anatomic land marks are located and marked in pencil.

•Lines that serve as planes are drown through the various points.

•When the planes intersect each other, they form accurately the angles.

•By the analysis of these angles, comparing them to a series of norms for the child's age

group .•The difference between the patient and the

norm's angles is considered :-•1))If the difference greater than a standard

deviation from a norm, it may be considered a skeletal malocclusion. This mean that there is

a vast dysplasia of the bony skeleton that orthodontic treatment may correct the

patient's dental malocclusion, the underlying bony dysplasia may be only disguised through

treatment, and not truly normalized.

•2)) If the difference not too far from the norm, ( small deviations ) this termed a

dental malocclusion. In which there is little osseous dysplasia of the dental

base and supporting bony tissue and the malocclusion problem is which the dental arches and duo is a malposition of dental

units only.

Limitation of roentgenographic cepholometric:

1) since the clinical practice of orthodontics deals with living children, the measuring instruments

must be limited to means which do not injury the patient and not give accurate information

2) When the three dimensional characters of the human face are measured on a roentgen gram,

photograph or tracing which presence a one dimensional surface. The results are not be

accepted as absolutely accurate, since variations which extend beyond the limits of normality may

be masked or distorted.

3) The reliability of lines, planes and angles employed in cephalometric analysis is subjects to variations due to the growth and development of the individual bones over which these are draw.

For example: the sella – nasion line which is use to denote the anterior cranial base to which the upper face is attached extends across the sphenoid, ethmoid, frontal and nasal bones. Another example: found in the land marked located around the foramen magnum in the occipital bone.