بسم الله الرحمن الرحيمبسم الله الرحمن الرحيم وقل رب زدنى علماوقل رب زدنى علما

Tooth Morphology

Permanent Maxillary Anterior Teeth

Prof. Dr. Naglaa Bahgat NagyProf. Dr. Naglaa Bahgat Nagy

Tooth Grouping

Anterior teeth: Incisors (central & lateral).Canine.

Posterior teeth:Premolars (1st & 2nd ).Molars (1st & 2nd & 3rd )

Characteristic Features of All Incisors(Maxillary & Mandibular)

• In each arch, there are four incisors (two incisors in each quadrant). They are located in the front of the mouth. The first incisor (the central incisor) is next to the midline. The second incisor (the lateral incisor) is distal to it.

• Incisors are single-rooted teeth with a relatively sharp thin blade-like crowns .

• Their incisal surfaces (the incisal ridges/edges) are designed to cut food without the application of heavy forces. Incisor means “that which makes an incision, or cut”.

• Their labial and lingual (palatal) surface are trapezoidal with the shortest uneven side located cervically.

• Their proximal surfaces (mesial & distal) are triangular in shape with the base of the triangle located cervically.

Characteristic Features of Maxillary Incisors (Central & Lateral)

• Maxillary incisors by definition arise in the pre-maxilla (which is merged into the maxilla in humans).

• When the mouth is closed, the maxillary incisors are normally located facial to the mandibular teeth (overjet & overbite).

• The maxillary central incisors occlude with the mandibular central and lateral incisors.

• Overbite refers to the extent of vertical overlap of the maxillary central incisors over the mandibular central incisors.

• Overjet is the horizontal distance between the maxillary anterior teeth and the mandibular anterior teeth.

Overbite (vertical) & Overjet (horizontal

Maxillary Permanent Incisors

Characteristic Features.

Notation (Numbering) System.

Chronology.

Morphology of its: Labial Surface. Palatal (lingual) Surface. Mesial Surface. Distal Surface. Incisal Surface (Ridge &Edge).

Pulp Cavity (pulp chamber & pulp canal).

Characteristic Features of

Maxillary Central incisor The most prominent The most prominent

teeth in the mouth. It is teeth in the mouth. It is almost the longest almost the longest inciso-cervically of all inciso-cervically of all human crown.human crown.

It is the widest tooth It is the widest tooth mesio-distally in mesio-distally in comparison to any comparison to any other anterior tooth.other anterior tooth.

Chronology

Evidence of calcification 3-4 months

Enamel completed 3-4 months

Eruption 7-8 years

Root completed 10 years

Notation(Numbering) System Maxillary Permanent Central Incisor

RIGHTLEFT

UNIVERSAL89

PALMER1| |1

FDI1121

Morphology of Permanent Morphology of Permanent Maxillary Central IncisorMaxillary Central Incisor

““The Right Side”The Right Side”

11

FDI

Dimensions of Maxillary Central Incisor

Morphology(Surface & Outlines)(Surface & Outlines)

1. Labial (Buccal) Aspect.

2. Palatal (Lingual) Aspect.

3. Mesial Aspect.

4. Distal Aspect.

5. Incisal Aspect.

1. The Labial Aspect

Crown Surface: Trapezoidal (shortest cervically). Slightly convex (in all directions) crest at cervical third). Two labial developmental grooves . Imbrication lines (incremental lines) Incisal Ridges (mamelons).

(a). Crown Outlines:1. Mesial outline:

Almost straight or slightly convex. Crest of curvature at the incisal third. The mesio-labial incisal angel is a sharp right angle.

2. Distal outline: More convex than the mesial outline. Crest approaches the junction of middle and incisal thirds. The disto-labial incisal angel is more rounded than the mesial one.

3. Incisal outline: Almost straight mesio-distally. Mamelons in newly erupted (incisal ridge & incisal edge).

4. Cervical outline: Convex root wise.

(b). Root Surface:• It is cone shaped with a blunt apex.

The Labial OutlinesThe Mesial, Incisal, Distal & Cervical Outlines

• The mesial outline is almost straight, crest of curvature (contact area) near the incisal angel.

• The mesio-incisal angle is almost a right angle.

• The disto-incisal angle is round.• The distal outline is slightly convex,

crest of curvature (contact area) near the junction of the middle and incisal thirds (more cervical than the mesial).

• The cervical outline is convex root-wise.

The Labial Aspect(b) The Root (Root Surface & Outlines)

Single root.

Slightly longer than the crown by about

2-3 mm.

• Cone-shaped.

Thick in the cervical third.

Narrows in the middle third and apical

third and ends with a blunt apex.

10.5m

13.0m

2. The Palatal (Lingual) Aspect The crown:

The crown tapers lingually.

Lingual Surface:

Trapezoidal (the shortest is located cervically).

Convex, concave, slightly convex.

The lingual aspect presents a distinctive lingual fossa that is

bordered by mesial and distal marginal ridges, the incisal ridge and

the prominent cingulum at the cervical third.

Mesial & Distal Outlines:

Mesial and distal outlines are the reverse of those found on the

labial surface.

• Cervical Outline: Convex root wise.

• Incisal Outline: almost straight with sharp-right mesio-incisal angle and

rounded disto-incisal angle.

The Root:

The root tapers lingually.

It is much narrower lingually than labially.

3. Mesial Aspect:

• The Crown:– Triangular in shape.– The incisal ridge is on line with the center of the root.– Location of the oval contact area.

Cervico-incisally in the incisal third. Labio-palatally, in the center

The Crown Outlines:– Labial outline:

• Convex.• Crest of curvature on the cervical third.

– Palatal (lingual) outline:• Convex at the cingulum.• Concave at the mesial marginal ridge.• Slightly convex at the incisal ridge.

– Cervical outline:• Concave root wise.

– Incisal outline:• In newly erupted teeth, it is rounded.• In teeth with occlusal wear, it is straight and slops

cervically from labial to palatal.• The root:

– Cone shaped.– Labial outline is straighter than the palatal– The apex is blunt.

4. Distal Aspect:

• Distal Surface:

There is little difference between mesial and distal outline.

The distal surface is more convex inciso-cervically than the

mesial surface.

The contact area is somewhat smaller and located at the

junction between the incisal and middle thirds.

• The cervical line is shallower distally than mesially.

5. The incisal Aspect:The incisal aspect is roughly triangular in shape.

The crown is wider mesio-distally than labio-lingually (which is

the reverse of all other teeth except mandibular molars).

The incisal ridge (edge) is relatively straight mesio-distally.

The incisal ridge is centered over the root.

The labial surface is convex.

The palatal surface shows convex cingulum that forms the crest

of contour palatally.

The mesial and distal outlines converge palatally and form

definite line angles with both the palatal and labial surfaces.

DD MM

Morphology of the Pulp Cavity:• The pulp is the soft connective tissue that has the

nerves and the blood supply of the tooth.• Frequently , the pulp chamber has three pulp horns.• In nearly all maxillary central incisors, there is only one

root, one canal and one foramen.• At the level of the cervical line, the shape of the canal

is triangular but becomes circular at the middle level of the root.

• Although the root canal is generally straight, the most common points of curvature is near the apex, and their direction is more common toward the distal and lingual.