The development of occlusion

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The development of occlusionThe development of occlusion

Agnieszka Pernak, PhD.S.1

SPECIFIC OBJECTIVESSPECIFIC OBJECTIVES

1. Follow the development of occlusion from birth to 3years.

2. Define and illustrate all of the terminal planerelationships for primary molars.

3. Explain canine relationships in the primary dentition.4. Follow the occlusion from 3-6 years.5. Know normal anterior relationships in the primary

dentition: Overjet, Overbite.6. Explain spacing in the primary dentition.

Agnieszka Pernak, D.D.S. 2

NeutrocclusionNeutrocclusionis a maximum intercuspidation of maxillary andmandibular teeth.

The development of occlusion is the most dynamicphenomenon in the mouth.

This is a permanent changing process from birth todeath.


Occlusion can be divided into four periodsOcclusion can be divided into four periods

11. Primary Dentition: 6 months - 6 years,

22. Mixed Dentition: 6-12 years,

33. Young Permanent Dentition: adolescence,

44. Adult Dentition.


Development of occlusionDevelopment of occlusion- The stomodeum is formed around 4 weeks in utero.

- Odontogenesis starts between the 30 and 40 day with the formation of theupper and lower dental lamina.

- Ten teeth germs (matching the number of deciduous teeth) develop in eachjaw (7 week in utero).

- The teeth germs of the permanent succedaneous teeth appear lingually toeach deciduous-tooth germ (24-30 weeks in utero - formation of the incisors,canines, premolars; 6th month postnatally - formation of the second molar, 5th

year of age a formation of the third molar).

- However the permanent first molar develops from distal extention of the dentallamina (16-17 weeks).

- Calcification of the primary teeth starts from the central incisors in the 4th

month in utero.

- Calcification of the permanent teeth starts from the first upper permanentmolars at the time of birth.

Agnieszka Pernak, D.D.S. 5 Agnieszka Pernak, D.D.S. 6

11. PRIMARY. PRIMARY DENTITIONDENTITION

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11. PRIMARY. PRIMARY DENTITIONDENTITION

5 months in utero

7 months in utero

PRENATAL STAGE – teeth mineralization


The shape of gingival arches at birthThe shape of gingival arches at birth


Bone trabeculae at fundusBone trabeculae at fundus

ApexApex

GingivaGingiva

EnamelEnamel


DentinDentinINFANT

Birth

6 mos.(± 2 mos.)

9 mos.(± 2 mos.)

1 year(± 3 mos.)

18 months(± 3 mos.)

TODDLER

INFANCY STAGE – teeth mineralization and eruption


INFANCY STAGE – central lower incisors eruption


FFirstirst and secondand secondphysiologicalphysiological deepbitedeepbite

First physiological deepbite


TODDLER

3

2 yrs(± 6 mos.)

3 yrs(± 6 mos.)

4 years(± 9 mos.)

5 yrs(± 9 mos.)

6 years(± 9 mos.)

CHILD

TODDLER

EARLY CHILDHOOD STAGE

– pre-school age


ESSENTIALESSENTIAL FACTORSFACTORS FORFOR AA SMOOTHSMOOTHTRANSITIONTRANSITION FROMFROM PRIMARYPRIMARY TOTO

PERMANENTPERMANENT DENTITIONDENTITION

a. Primate space.

b. General spacing.

c. Preservation of “leeway space”“leeway space”.

d. Sequences of eruption.

e. Teeth size and jaw in harmony.


a.a. Primate spacePrimate space- is a proper spacing of the primary dentition before teeth exchange

- in the maxillary arch the primate space is located between thelateral incisors and canines

- in the mandibular arch the primate space is located between thecanines and first molars


Primate spacePrimate space


Primate spacePrimate space

UPPER ARCH

LOWER ARCH


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bb. General spacing. General spacing


cc. Preservation of. Preservation of „leeway„leeway spacespace””

the combined width of thedeciduous first molar and secondmolar is greater than that of theirpermanent successors

Agnieszka Pernak, D.D.S.

Total width of premolars

Total width of primary molars

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d.d. Chronology of tooth developmentChronology of tooth developmentin primary dentitionin primary dentition


Maxillary teeth

Mandibular teeth

Months 8 10 13 16 19 2729

1

2 4 3 51

2 4 3 5

Chronology of tooth development inChronology of tooth development inprimary dentitionprimary dentition


e.e. TTEETH SIZE AND JAW IN HARMONYEETH SIZE AND JAW IN HARMONY

PRIMARY DENTITIONPRIMARY DENTITION


SHAPE OF THE DENTAL ARCHES INSHAPE OF THE DENTAL ARCHES INPRIMARY DENTITIONPRIMARY DENTITION

semicilcular for upper and lower dental arch


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FLUSH TERMAL PLANEFLUSH TERMAL PLANE – in a 3 years old patients is a

TTHE THEETH RELATIONSHIPHE THEETH RELATIONSHIP

NORMNORM


MMESIAL STEPESIAL STEP – in a 5 years old patients is a


NORMNORM


LOCAL,LOCAL, SYSTEMICSYSTEMIC ANDAND CONGENITALCONGENITAL FACTORSFACTORSTHATTHAT CANCAN INFLUENCEINFLUENCE THETHE TEETHTEETH ERUPTIONERUPTION

Local

Systemic

Congenital

• Two rows of teeth• Ectopic eruption• Infected primary teeth• Ankylosis

• Primary failure of eruption• Hypothyroidism

• Down’s Syndrome• Achondroplastic Dwarfism• Cleidocranial Dysplasia


Two rows of teethTwo rows of teeth


Ectopic eruption


Infected primary toothInfected primary tooth


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22. MIXED. MIXED DENTITIONDENTITION


STEPSSTEPS OFOF TOOTHTOOTH ERUPTIONERUPTION

1. Pre-emergent eruption - Pre-eruptive phasea) resorption of the bone and primary tooth

rootsb) the eruption mechanism


2. Post-emergent eruption - Eruptive phasea) post-emergent spurt - Eruptive phase

(Pre-functional)b) juvenile occlusal equilibrium

Eruptive phase (Functional)

c) adult occlusal equilibrium


Primary toothPrimary tooth

EnamelEnamel

Permanent toothPermanent tooth

ApexApex

Bone trabeculae at fundusBone trabeculae at fundus


Calcificationbegins

Crowncompleted

Eruption Root completed

Tooth Max. Mand. Max. Mand. Max. Mand. Max. Mand.

Central 3 mo. 3 mo. 4 ½ yr. 3 ½ yr. 7 ¼ yr. 6 ¼ yr. 10 ½ yr. 9 ½ yr.

Lateral 11 mo. 3 mo. 5 ½ yr. 4 yr. 8 ¼ yr. 7 ½ yr. 11 yr. 10 yr.

Canine 4 mo. 4 mo. 6 yr. 5 ¾ yr. 11 ½ yr. 10 ½ yr. 13 ½ yr. 12 ¾ yr.

1st PreMolar

20 mo. 22 mo. 7 yr. 6 ¾ yr. 10 ¼ yr. 10 ½ yr. 13 ½ yr. 13 ½ yr.

2nd PreMolar

27 mo. 28 mo. 7 ¾ yr. 7 ½ yr. 11 yr. 11 ¼ yr. 14 ½ yr. 15 yr.

1st Molar 32 wk.in utero

32 wk.in utero

4 ¼ yr. 3 ¾ yr. 6 ¼ yr. 6 yr. 10 ½ yr. 10 ¾ yr.

2nd Molar 27 mo. 27 mo. 7 ¾ yr. 7 ½ yr. 12 ½ yr. 12 yr. 15 ¾ yr. 16 yr.

3rd Molar 8 yr. 9 yr. 14 yr. 14 yr. 20 yr. 20 yr. 22 yr. 22 yr.

Chronology of tooth development inChronology of tooth development inppeerrmanentmanent dentitiondentition


Maxillary teeth

Mandibular teeth

Years 6 8 10

6

2 43 56

2 4 35

12 20

7

1

1

7 8

8

Chronology of tooth development inChronology of tooth development inppeerrmanentmanent dentitiondentition


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TTEETH SIZE AND JAW IN HARMONYEETH SIZE AND JAW IN HARMONY

PERMANENT DENTITIONPERMANENT DENTITION


SHAPE OF THE DENTAL ARCHES INSHAPE OF THE DENTAL ARCHES INPERMANENT DENTITIONPERMANENT DENTITION

semieliptic parabolic


TTHE WIDTH OF THE DENTAL ARCHESHE WIDTH OF THE DENTAL ARCHES

the maxilla should be wider thenthe mandible in approximately1-2mm on each side

in the relation to each other


TTHE WIDTH OF THE DENTAL ARCHESHE WIDTH OF THE DENTAL ARCHESin the relation to thethe basalbasal bonebone

normal narrow wide



the buccal cusps of maxillary molars and premolars covers the buccalsurface of the teeth in the mandible

the intercuspidation – one tooth meets two teeth in the opposite arch


ERUPTIONERUPTION SEQUENCESEQUENCE ANDANDTIMINGTIMING

Age 6: 16, 26, 36, 46, 41, 31Age 8: 42, 32, 11, 12, 21, 22Age 11: 33, 34, 43, 44, 14, 24Age 12: 13, 23, 35, 45, 15, 25


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MESIAL STEP

BECAUSE OF THE MESIAL STEP I PERMANENT MOLARSERUPT IN CUSP-GROOVE RELATIONSHIP

6/6

6/66/6

6/6

5 year old patient

6 year old patient


ERUPTION OF PERMANENT MOLARSERUPTION OF PERMANENT MOLARS

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ERUPTIONERUPTION OFOF PERMANENTPERMANENT MOLARSMOLARS


AgeAge 66: 16, 26, 36, 46, 41, 31


7

7

6

6

thethe molars relationshipmolars relationship

(mesial step)


I CLASSI CLASS

NORM

Angle classificationAngle classification

Edward H. Angle,Edward H. Angle, 18901890

the mesio-buccal cusp of the upperfirst molar occludes with the mesi-obuccalgroove of the lower first molar

5

5 4

4

I CLASSI CLASS


DEVIATION

NORM

II CLASSII CLASS III CLASSIII CLASS

I CLASSI CLASS4

45

5

4

45

5 4

45

5


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AgeAge 88:: 42, 32, 11, 12, 21, 22


7 years old 9 years old 14 years old

Changes in the dentition according to Broadbent, 1957.

„„UGLY DUCKLINGUGLY DUCKLING” STAGE” STAGE– is a period when the maxillary incisors flare laterally and are

widely spread

– the diastema between the maxillary permanent centralincisors tends to close as the permanent canines erupt



At dental age 9, the maxillarylateral incisors have been inplace for 1 year, and rootformation on other incisorsand first molars is nearlycomplete.


AgeAge 99

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First and secondFirst and secondphysiological deepbitephysiological deepbite

Second physiological deepbite


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Dental age 11 is characterizedby the more or lesssimultaneous eruption of themandibular canines,mandibular first premolars,and maxillary first premolars.

AgeAge 1111:: 33, 34, 43, 44, 14, 24


Dental age 12 ischaracterized by eruption ofthe remaining succedaneousteeth (the maxillary canineand the maxillary andmandibular secondpremolars)and, typically a few monthsalter, the maxillary andmandibular second molars.

AgeAge 1212:: 13, 23, 35, 45, 15, 25


43

17

25

5

47

the canine rulethe canine rule

the long axis of the uppercanine should be between the lowercanine and the first permanentpremolar


OVERJETOVERJET– is defined as horizontal overlap

of the incisors

– the incisal edge of lowerincisors contacts the palatal surfaceof the upper incisors

– the 2-3mm overjet is the normalrelationship



OVERBITEOVERBITE– is a vertical overlap of the incisors

– the incisal edge of lower incisorscontacts the palatal surface ofthe upper incisors

– the 2-3mm overbite is the normalrelationship

Exceptions:Exceptions:- first physiological deepbite- second physiological deepbite


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33. YOUNG PERMANENT. YOUNG PERMANENTDENTITIONDENTITION


By dental age 15, the rootsof all permanent teethexcept the third molars arecomplete, and crownformation of third molarsoften has been completed.


AgeAge 1155

63

Late crowding of lower incisorsLate crowding of lower incisors

1. Lack of attrition on interproximal srfaces (+ natural mesialdrift of prmanent molars)

2. Lack of attriton on occlusal surfaces (imploson of dentalarches)

3. Pressure from third molars4. Late mandibular growth



SSUMMERYUMMERY of growth periods in the occlusion development1. Newborns and infants without teeth2. Eruption of primary dentition

first phisiological deepbite3. Full primary dentition

spacingprimate spaceflush termal plane

4. Just before dental exchangebiger spacingattrition of occlusal surfacedifferential growth of mandible and maxillamesial stepedge to edge overbite and overjet – possiblespace for first permanent molars

5. Mixed dentitiontemporary crowding of erupting lower incisors – possibleugly duckling stagesecond phisiological deepbite

6. Permanent dentition

Six keys of occlusionSix keys of occlusion(acording to Andrews)(acording to Andrews)

1. Molar relationship2. Mesio-distal crown angulation (inclination)3. Labio-lingual position of crowns (torque)4. No rotations5. Maintained contact points6. The occlusal plane and curve of Spee


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11.. Molar relationshipMolar relationship

7

7

6

6

The mesio-buccal cusp of theupper first molar occludes with themesio-buccal groove of the lower firstmolar


(mesial step)I CLASSI CLASS

22. Mesio. Mesio--distal crown angulation (distal crown angulation (inclinationinclination))


AngulationAngulation, inclinationinclination– the alignment of a tooth in a vertical plane in

relationship to its basal bone structure– the gingival part of the crown should be more

distal than the occlusal part

2525ºº

occlusalocclusal planeplane

33. Labio. Labio--lingual positon of crowns (lingual positon of crowns (torquetorque))

-- 11ºº

++ 77ºº

1616ºº


TorqueTorque – the rotation of a tooth on its long axis,especially the movement of the apical portionsof the teeth by use of orthodontic appliances

For the incisorsFor the incisors- a positive angle between the tangent

to the middle part of the labialsurface of the crown and theperpendicular to the occlusal plane

occlusalocclusal planeplane

33. Labio. Labio--lingual positon of crowns (lingual positon of crowns (torquetorque))


TorqueTorque – the rotation of a tooth on its long axis,especially the movement of the apical portionsof the teeth by use of orthodontic appliances

1616ºº

-- 1919ºº

For the posterior teethFor the posterior teeth- a negative angle between the tangent

to the middle part of the labialsurface of the crown and theperpendicular to the occlusal plane

44.. No rotationsNo rotations

In a proper occlusion there are no rotations.

Rotated molars and premolars need more space in thedental arches where incisors need les space.


55.. Maintained contact pointsMaintained contact points

Contact pointsContact points – are maintained for stable treatment effect.


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66. The. The occlusalocclusal plane and curve ofplane and curve of SpeeSpeeCurve ofCurve of SpeeSpee

it is created by contact points on upper and lower teethin milk dentition it is flatin permanent dentition it is curved

maxillamaxilla – convex

1,5-2mm

mandiblemandible – concave

Agnieszka Pernak, D.D.S. 73 Agnieszka Pernak, D.D.S.

THE END!THE END!

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The development of occlusion