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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.
Agnieszka Pernak, D.D.S. 3
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.
Agnieszka Pernak, D.D.S. 4
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
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The shape of gingival arches at birthThe shape of gingival arches at birth
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Bone trabeculae at fundusBone trabeculae at fundus
ApexApex
GingivaGingiva
EnamelEnamel
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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
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INFANCY STAGE – central lower incisors eruption
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FFirstirst and secondand secondphysiologicalphysiological deepbitedeepbite
First physiological deepbite
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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
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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.
Agnieszka Pernak, D.D.S. 15
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
Agnieszka Pernak, D.D.S. 16
Primate spacePrimate space
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Primate spacePrimate space
UPPER ARCH
LOWER ARCH
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bb. General spacing. General spacing
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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
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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
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e.e. TTEETH SIZE AND JAW IN HARMONYEETH SIZE AND JAW IN HARMONY
PRIMARY DENTITIONPRIMARY DENTITION
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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
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MMESIAL STEPESIAL STEP – in a 5 years old patients is a
TTHE THEETH RELATIONSHIPHE THEETH RELATIONSHIP
NORMNORM
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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
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Two rows of teethTwo rows of teeth
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Ectopic eruption
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Infected primary toothInfected primary tooth
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22. MIXED. MIXED DENTITIONDENTITION
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STEPSSTEPS OFOF TOOTHTOOTH ERUPTIONERUPTION
1. Pre-emergent eruption - Pre-eruptive phasea) resorption of the bone and primary tooth
rootsb) the eruption mechanism
Agnieszka Pernak, D.D.S. 32
2. Post-emergent eruption - Eruptive phasea) post-emergent spurt - Eruptive phase
(Pre-functional)b) juvenile occlusal equilibrium
Eruptive phase (Functional)
c) adult occlusal equilibrium
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Primary toothPrimary tooth
EnamelEnamel
Permanent toothPermanent tooth
ApexApex
Bone trabeculae at fundusBone trabeculae at fundus
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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
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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
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SHAPE OF THE DENTAL ARCHES INSHAPE OF THE DENTAL ARCHES INPERMANENT DENTITIONPERMANENT DENTITION
semieliptic parabolic
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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
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TTHE WIDTH OF THE DENTAL ARCHESHE WIDTH OF THE DENTAL ARCHESin the relation to thethe basalbasal bonebone
normal narrow wide
Agnieszka Pernak, D.D.S. 40
TTHE THEETH RELATIONSHIPHE THEETH RELATIONSHIP
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
Agnieszka Pernak, D.D.S. 41
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
Agnieszka Pernak, D.D.S. 42
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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
Agnieszka Pernak, D.D.S.
ERUPTION OF PERMANENT MOLARSERUPTION OF PERMANENT MOLARS
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ERUPTIONERUPTION OFOF PERMANENTPERMANENT MOLARSMOLARS
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AgeAge 66: 16, 26, 36, 46, 41, 31
Agnieszka Pernak, D.D.S. 45
7
7
6
6
thethe molars relationshipmolars relationship
(mesial step)
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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
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DEVIATION
NORM
II CLASSII CLASS III CLASSIII CLASS
I CLASSI CLASS4
45
5
4
45
5 4
45
5
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9
AgeAge 88:: 42, 32, 11, 12, 21, 22
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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
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Agnieszka Pernak, D.D.S. 51 Agnieszka Pernak, D.D.S. 52
At dental age 9, the maxillarylateral incisors have been inplace for 1 year, and rootformation on other incisorsand first molars is nearlycomplete.
Agnieszka Pernak, D.D.S.
AgeAge 99
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First and secondFirst and secondphysiological deepbitephysiological deepbite
Second physiological deepbite
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10
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
Agnieszka Pernak, D.D.S. 55
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
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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
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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
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Agnieszka Pernak, D.D.S. 59
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
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By dental age 15, the rootsof all permanent teethexcept the third molars arecomplete, and crownformation of third molarsoften has been completed.
Agnieszka Pernak, D.D.S.
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
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Agnieszka Pernak, D.D.S. 65
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
Agnieszka Pernak, D.D.S. 66
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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
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(mesial step)I CLASSI CLASS
22. Mesio. Mesio--distal crown angulation (distal crown angulation (inclinationinclination))
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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
Agnieszka Pernak, D.D.S. 69
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))
Agnieszka Pernak, D.D.S. 70
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.
Agnieszka Pernak, D.D.S. 71
55.. Maintained contact pointsMaintained contact points
Contact pointsContact points – are maintained for stable treatment effect.
Agnieszka Pernak, D.D.S. 72
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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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