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OrthodonticsOrthodontics
Hospital of Stomatology,Xi’an Jiaotong UniversityHospital of Stomatology,Xi’an Jiaotong University
Department of OrthodonticsDepartment of Orthodontics
Professor ZhouHongProfessor ZhouHong
overviewoverview Orthodontics is a branch of Clinical StomatologyOrthodontics is a branch of Clinical Stomatology , the mechanisms of , the mechanisms of
major research and development of dentofacial deformities, major research and development of dentofacial deformities,
diagnosis, prevention and treatment.diagnosis, prevention and treatment.
OrthoOrthodonticsdontics Dentofacial OrthopedicsDentofacial Orthopedics
MalMalocclusionocclusion Dentofacial DeformityDentofacial Deformity
Orthodontics and Dentofacial orthopedics
Orthodontics and Dentofacial orthopedics
The area and specialty of dentistryThe area and specialty of dentistry concerned with the concerned with the supervision, guidance and correction supervision, guidance and correction of the growing of the growing or mature dentofacial structures, including those or mature dentofacial structures, including those conditions that require conditions that require movement of teeth movement of teeth or or correctioncorrection of malrelationships and malformationsof malrelationships and malformations of of their related structures and their related structures and the adjustment the adjustment of of relationships between and among teeth and facial bones relationships between and among teeth and facial bones by the application of forces by the application of forces and/or and/or the stimulation the stimulation and redirectionand redirection of functional forces within the of functional forces within the craniofacial complex.craniofacial complex.
Major responsibilities Major responsibilities of orthodontic practice include of orthodontic practice include the diagnosis, prevention, interception and the diagnosis, prevention, interception and treatment treatment of all forms of malocclusion of the teeth and of all forms of malocclusion of the teeth and associated alterations of their surrounding structures; associated alterations of their surrounding structures; the design, application and control the design, application and control of functional and of functional and corrective appliances; and corrective appliances; and the guidance the guidance of the dentition of the dentition and its supporting structures to attain and maintain and its supporting structures to attain and maintain optimal occlusal relations, physiologic function and optimal occlusal relations, physiologic function and esthetic harmony of facial and cranial structures.esthetic harmony of facial and cranial structures.
Orthodontics and Dentofacial orthopedics
Dentofacial deformity
A malformation of the A malformation of the teethteeth, , jawsjaws and/or and/or faceface
characterized by disharmonies of characterized by disharmonies of sizesize,, form form
and/orand/or function function. The term encompasses . The term encompasses
problems such as problems such as malocclusionmalocclusion, , cleft lip and cleft lip and
palatepalate and other skeletal or soft tissue and other skeletal or soft tissue
anomaliesanomalies, or , or syndromessyndromes that involve the face that involve the face
and the dentoalveolar complex.and the dentoalveolar complex.
一、一、 The manifestation of Dentofacial The manifestation of Dentofacial DeformityDeformity
11 malposition of individual, abnormity of arch malposition of individual, abnormity of arch
formform ,tooth malalignment,tooth malalignment
22 maxillomandibular malrelationshipmaxillomandibular malrelationship
3 3 malrelationship between jaw and craniummalrelationship between jaw and cranium
二、二、 epidemiology epidemiology
prevalence rareprevalence rare : : 60`s:60`s: 29.33% - 48.87%29.33% - 48.87%
2000`s:2000`s: 51.84 – 72.92% 51.84 – 72.92%
Individual Normal OcclusionIndividual Normal Occlusion
Ideal Normal Occlusion Ideal Normal Occlusion
Incisor Irregularity Index Incisor Irregularity Index
A+B+C+D+E= Anterior lower incisor crowding
0-1 ideal0-1 ideal2-3 mild crowding2-3 mild crowding4-6 moderate crowding4-6 moderate crowding7-10 severe crowding7-10 severe crowding> 10 extreme crowding> 10 extreme crowding
三、 三、 Perniciousness Perniciousness
11 psychosocial influences psychosocial influences
22 oral function oral function
3 3 relation to dental diseaserelation to dental disease
44 Aesthetic impact Aesthetic impact
Relation between size of overjet and
prevalence of traumatised anterior teeth
Overjet (mm) Incidence % 5 22 9 24 >9 44
Dr Sarver:Dr Sarver:
Malocclusion of teeth is not disease , Malocclusion of teeth is not disease ,
rather, it is a disability with a potential rather, it is a disability with a potential
influence on physical and mental health.influence on physical and mental health.
Orthodontics Orthodontics — — current principles and techniquescurrent principles and techniques
2000 By Graber2000 By Graber
Reason for orthodontics
1. To improve dentofacial appearance.
2. To correct the occlusal function of the teeth
3. To eliminate occlusion that could damage the
long-term health of the teeth and periodontium
四、 standard and target
11 、 、 changeschanges of targetof target Crowed,irregular and protruding teeth have Crowed,irregular and protruding teeth have
been a problem for some individuals since been a problem for some individuals since antiquity,and attempts to correct this antiquity,and attempts to correct this disorder go back at least to 1000 BC.primitive disorder go back at least to 1000 BC.primitive orthodontic appliance have been found in orthodontic appliance have been found in both Greek and Etruscan matrials.both Greek and Etruscan matrials.
1850 the first texts that 1850 the first texts that
systematically described systematically described orthodontics appeared,the orthodontics appeared,the most notable being Norman most notable being Norman Kingsley’s Oral Kingsley’s Oral Deformities.Kingsley who had Deformities.Kingsley who had a tremendous influence on a tremendous influence on American dentistry in the American dentistry in the latter half of the nineteeth latter half of the nineteeth century,was among the first to century,was among the first to use extroral force to correct use extroral force to correct protruding teeth.He was also a protruding teeth.He was also a pioneer in the treatment of pioneer in the treatment of celft palate and related celft palate and related problems.problems.
Their emphasis in orthodontics remaind the Their emphasis in orthodontics remaind the
alignment of the teeth and the correction of facial alignment of the teeth and the correction of facial
proportions. Little attention was paid to the dental proportions. Little attention was paid to the dental
occlusion.In an era when an intact dentition was a occlusion.In an era when an intact dentition was a
rarity,the details of occlusal relationships were rarity,the details of occlusal relationships were
considered unimportant.considered unimportant.
Edward H Angle can be Edward H Angle can be credited with much of the credited with much of the development of a concept of development of a concept of occlusion in the natural occlusion in the natural dentition.His increasing dentition.His increasing interest in dental occlusion interest in dental occlusion and in the treatment and in the treatment necessary to obtain normal necessary to obtain normal occlusion led directly to his occlusion led directly to his development of orthodontis development of orthodontis as a specialty,with himself as as a specialty,with himself as the “father of modern the “father of modern orthodontics.”orthodontics.”
The publication of Angle’s The publication of Angle’s classification of classification of malocclusion in the 1890s malocclusion in the 1890s was an important step in was an important step in the development of the development of orthodontics because it not orthodontics because it not only subdivided major only subdivided major types of malocclusion but types of malocclusion but also included the first also included the first clear and simple definition clear and simple definition of normal occlusion in the of normal occlusion in the natural dentition.If this natural dentition.If this molar relationship existed molar relationship existed and the teeth were and the teeth were arranged on a smoothly arranged on a smoothly curving line of occlusion.curving line of occlusion.
Orthodontics was no longer just the alignment of Orthodontics was no longer just the alignment of
irregular teeth.Angle and his followers strongly irregular teeth.Angle and his followers strongly
opposed extraction for orthodontic purpose.With the opposed extraction for orthodontic purpose.With the
emphasis on dental occlusion that emphasis on dental occlusion that
followed,however,less attention came to be paid to followed,however,less attention came to be paid to
facial proportions and esthetics.facial proportions and esthetics.
As time passed,it became clear that even an As time passed,it became clear that even an excellent occlusion was unsatisfactory if it was excellent occlusion was unsatisfactory if it was achieved at the expense of proper facial achieved at the expense of proper facial proportions.Not only were there esthetic proportions.Not only were there esthetic problems,it often proved impossible to maintain problems,it often proved impossible to maintain an occlusal relationship.Extraction of teeth was an occlusal relationship.Extraction of teeth was reintroduced into orthodontics in the 1930s to reintroduced into orthodontics in the 1930s to enhance facial esthetics and achieve better enhance facial esthetics and achieve better stability of the occlusal relationships.stability of the occlusal relationships.
Cephalometric radiography enabled orthodontists Cephalometric radiography enabled orthodontists
to measure the changes in tooth and jaw positions to measure the changes in tooth and jaw positions
produced by growth and treatment.These radiographs produced by growth and treatment.These radiographs
made it clear that many malocclusions resulted from made it clear that many malocclusions resulted from
faulty jaw relationships,not just malposed teeth.By use faulty jaw relationships,not just malposed teeth.By use
of cephalometrics,it also was possible to see that jaw of cephalometrics,it also was possible to see that jaw
growth could be altered by orthodontic treatment.growth could be altered by orthodontic treatment.
As the 21As the 21st st century begins,orthodontics century begins,orthodontics
differs from what was done previously in differs from what was done previously in
three important ways:three important ways:
⑴ ⑴ there is more emphasis now on there is more emphasis now on
dental and facial esthetics, and less on dental and facial esthetics, and less on
details of dental occlusion.details of dental occlusion.
⑵⑵ patients now expect and are granted a patients now expect and are granted a
greater degree of involvement in planning greater degree of involvement in planning
treamenttreament 。。 No longer is it appropriate for the No longer is it appropriate for the
paternalistic doctor to simply tell patients what paternalistic doctor to simply tell patients what
treament they should have.treament they should have.
⑶ ⑶ orthodontics now is offered much orthodontics now is offered much
frequently to older patients as part of a frequently to older patients as part of a
multidisciplinary treament plan involing multidisciplinary treament plan involing
other dental and medical specialtiesother dental and medical specialties 。。
(( Multidisciplinary Treatment Multidisciplinary Treatment ))
(( Interdisciplinary Treatment Interdisciplinary Treatment ))
The goal is not necessarily the best possible The goal is not necessarily the best possible dental occlusion or facial esthetics but the best dental occlusion or facial esthetics but the best chance for long-term maintenance of the chance for long-term maintenance of the dention.This increased emphasis on treatment dention.This increased emphasis on treatment coordinated with other dentists has the effect of coordinated with other dentists has the effect of integrating orthodontics back into the main integrating orthodontics back into the main stream of dentistry,from which Angle’s stream of dentistry,from which Angle’s teachings had tended to separate it.teachings had tended to separate it.
⑵ ⑵ Andrews ’s sixElements Andrews ’s sixElements ::1. Molar relationship1. Molar relationship
2. Crown angulation (Mesiodistal “tip”) 2. Crown angulation (Mesiodistal “tip”)
3. Crown inclination 3. Crown inclination
4. Rotations 4. Rotations
5. Spaces 5. Spaces
6. Occlusal plane6. Occlusal plane
五、五、 The relationship between orthodontics The relationship between orthodontics
and other subjects and other subjects
11 、、 ProsthodonticsProsthodontics
22 、、 implantodontics implantodontics
33 、 、 periodonticsperiodontics
44 、、 Computer TechnologyComputer Technology
55 、 、 MaterialogyMaterialogy
significant development in stomatology are related to materials
enamel adhesiveenamel adhesive The super-elastic titanium alloy arch wireThe super-elastic titanium alloy arch wire implant anchorageimplant anchorage
六、六、 methodsmethods
1. Preventive Orthodontics1. Preventive Orthodontics antenatal careantenatal care
regular oral examination regular oral examination
Get rid of bad habits Get rid of bad habits
space maintainerspace maintainer
extractions of Supernumerary Teeth extractions of Supernumerary Teeth
2. Interceptive Orthodontics2. Interceptive Orthodontics
serial extractionserial extraction
early treatment of crossbiteearly treatment of crossbite
3. general Orthodontics3. general Orthodontics
Removable appliances
fixed appliances
function appliances
lnvisalignlnvisalign appliances appliances
Dental digital modeling and invisible appliance
牙颌光固化在牙轿器技术流程中的位置
Dental data
laminar analysis
Reverse correction
appliance mold
appliance
4. Orthodontics - Surgical 4. Orthodontics - Surgical
correctioncorrection
Orthognthic Surgery Orthognthic Surgery
Surgical OrthodonticsSurgical Orthodontics
Distraction OsteogenesisDistraction Osteogenesis
obliqueoblique split split ramus ramus osteotomyosteotomy
sagittal split sagittal split ramus ramus osteotomyosteotomy
In the 20th century, major developments :In the 20th century, major developments : MonoblocMonobloc ,, 19201920 ,, PierrePierre EdgewiseEdgewise ,, 19281928 ,, AngleAngle
BeggBegg 、、 Straight-wireStraight-wire 、、 TipedgeTipedge X-cephalometryX-cephalometry ,, 19311931 ,, BroadbentBroadbent EatractionEatraction ,, 19411941 ,, TweedTweed
Orthodontic Materials and Bio-mechanicsOrthodontic Materials and Bio-mechanics Wire Materials, gold, stainless steel, O wire, hot-Wire Materials, gold, stainless steel, O wire, hot-
activated, nickel, titanium and titanium ßactivated, nickel, titanium and titanium ß Tooth movement, Burstone, power systems, force Tooth movement, Burstone, power systems, force
size, force directionsize, force direction Bonding technologyBonding technology Orthognathic surgery and orthodonticsOrthognathic surgery and orthodontics Computer applicationsComputer applications 80`s 80`s
In 21st century ,the direction of the development In 21st century ,the direction of the development
of orthodonticsof orthodontics
Craniofacial growth and developmentCraniofacial growth and development
Biology of tooth movementBiology of tooth movement
Biomechanics and BioMaterialsBiomechanics and BioMaterials
Computer use in orthodonticsComputer use in orthodontics
Three Dimensional DiagnosisThree Dimensional Diagnosis
Interdisciplinary TreatmentInterdisciplinary Treatment
Craniofacial Growth and Craniofacial Growth and DevelopmentDevelopment
一、一、 methods of collecting informationmethods of collecting information
longitudinal study longitudinal study
cross-sectional study cross-sectional study
mixed longitudinal studymixed longitudinal study
二、二、 1. 1. Measurement StudyMeasurement Study
CraniometryCraniometry
AnthropometryAnthropometry
Cephalometry Cephalometry
•techniques for measuring living techniques for measuring living individualsindividuals
• Three-dimensional structure Three-dimensional structure
•surface measurementsurface measurement
•Poor accuracy Poor accuracy
•The stability of the measurement The stability of the measurement system and method )system and method )
•The basis for evaluation of facial The basis for evaluation of facial morphology morphology
•studying the deep structure is studying the deep structure is impossible)impossible)
Anthropometry Anthropometry
二、二、 2 .2 . experimentexperiment
Vital stainingVital staining
Radioactive TracerRadioactive Tracer
Implant radiographyImplant radiography
Molecular GeneticsMolecular Genetics
三、 三、 basic conceptbasic concept
1. 1. (( Growth PattenGrowth Patten ))
Pattern of facial growth Pattern of facial growth ::
Average growth patternAverage growth pattern
Horizontal growth patternHorizontal growth pattern Vertical growth patternVertical growth pattern
2. Variability2. Variability
Everyone is not alike in the way Everyone is not alike in the way
that they grow as in everyting else.It can that they grow as in everyting else.It can
be difficult but clinically very important be difficult but clinically very important
to decide whether an individual is merely to decide whether an individual is merely
at the extreme of the normal variation or at the extreme of the normal variation or
falls outside the normal range.falls outside the normal range.
Variability
Racial and ethnic differencesRacial and ethnic differences GenderGender SicknessSickness nutritionnutrition Timing factor -Late/early maturersTiming factor -Late/early maturers Problems with growth (hormones or genetics)Problems with growth (hormones or genetics)
3. Timing 3. Timing Variability in growth arises in Variability in growth arises in
several ways:from normal variation,from several ways:from normal variation,from timing effects.Variation in timing arises timing effects.Variation in timing arises because the same event happens for because the same event happens for different individuals at different times.different individuals at different times.
developmental age and chronologic agedevelopmental age and chronologic age
Timing Variation
Early, average, and late matuerersEarly, average, and late matuerers Chronological age vs. Developmental ageChronological age vs. Developmental age
4.4. Rapid phase of growth and development Rapid phase of growth and development
Rapid and slow phase of Rapid and slow phase of
craniofacial growth and development is craniofacial growth and development is
close to rapid and slow phase of body close to rapid and slow phase of body
growth and development .growth and development .
Why do we assess growth?
To determine optimum time for treatment To determine optimum time for treatment (growth modification and surgery)(growth modification and surgery)
to determine the amount of growth leftto determine the amount of growth left to determine type of growthto determine type of growth
5.5. Growth site and Growth centerGrowth site and Growth center
A site of growth is merely a location at A site of growth is merely a location at which growth occurs,whereas a center is a which growth occurs,whereas a center is a location at which independent (genetically location at which independent (genetically controlled) growth occurs.All growth controlled) growth occurs.All growth centers also are growth sites, whereas the centers also are growth sites, whereas the reverse is not true. reverse is not true.
Growth Center and Growth SiteGrowth Center and Growth Site
For example, it is now known that the sutures For example, it is now known that the sutures between the membranous bones of the cranium between the membranous bones of the cranium and the maxilla that previously were considered and the maxilla that previously were considered as primary growth centers, actually are mere as primary growth centers, actually are mere sites of growth. sites of growth.
Questions
Do you know the hazards of Dentofacial Do you know the hazards of Dentofacial deformities? deformities? Orthodontic treatment goal? Orthodontic treatment goal? What is ideal normal occlusion , what is What is ideal normal occlusion , what is individual normal occlusionindividual normal occlusion ??What is the growth pattern? What is the growth pattern? What is the growth site and growth center?What is the growth site and growth center?
四、四、 postnatal Craniofacial Growth and postnatal Craniofacial Growth and DevelopmentDevelopment
1. 1. Craniofacial dividing lineCraniofacial dividing line
Bolton – nasionBolton – nasion planeplane
FrankfortFrankfort planeplane
Ba-N planeBa-N plane
Bolton - Bolton - 鼻根平面, 鼻根平面, A line A line connecting points Bolton and connecting points Bolton and Nasion; an alternate representation Nasion; an alternate representation of the cranial base.of the cranial base.
FrankfortFrankfort 平面平面
全颅底平面(全颅底平面( N – BaN – Ba ))To represent the cranial base more To represent the cranial base more accurately than the SN line or the Bolton accurately than the SN line or the Bolton plane.plane.
前颅底平面( S-N ) Representing the anterior cranial base. A line joining points S and Na.
2. ways of Bone growth and 2. ways of Bone growth and
developmentdevelopment
⑴ ⑴ surface apposition of bonesurface apposition of bone
periosteumperiosteum osteoblastosteoblast osseous tissueosseous tissue
⑵ ⑵ interstitial growthinterstitial growth
Connective tissue cells Fibroblast Collagen Connective tissue cells Fibroblast Collagen
fibers and matrix calcificationfibers and matrix calcification
⑶ ⑶ central cartilage cell proliferate central cartilage cell proliferate
hypertrophy hypertrophy Peripheral cartilage Peripheral cartilage
calcificationcalcification
Cells ofCells of deep Connective tissue membrane deep Connective tissue membrane
differentiate into cartilage cells and matrix form differentiate into cartilage cells and matrix form hyaline cartilage, that calcifiy into new bonehyaline cartilage, that calcifiy into new bone
Reserve zones (RZ)
Proliferating zones (PZ)
Prehypertrophic zones (PHZ)
Hypertrophic zones (HZ)
Articular cartilage (AC)
Growth cartilage (GC)
3. Cranial growth and development 3. Cranial growth and development
A. A. cranial cavitycranial cavity
functionfunction :: protecting the brain protecting the brain
structurestructure :: flat boneflat bone
Site and mechanism of the growth Site and mechanism of the growth ::suture and Surface hyperplasiasuture and Surface hyperplasia
timing:timing: (( 6-7 years old 6-7 years old
reach 90% of people reach 90% of people )) Clinical SignificanceClinical Significance : :
Aperts Syndrome Aperts Syndrome
Major Features of Apert Syndrome Major Features of Apert Syndrome Prematurely fused cranial suturesPrematurely fused cranial sutures A retruded midfaceA retruded midface Fused fingers Fused fingers Fused toes Fused toes
B. cranial baseB. cranial base
functionfunction :: stabilitystability
growth site and timinggrowth site and timing :: The The
growth of cartilage growth of cartilage
(( intersphenoid synchondrosisintersphenoid synchondrosis 、、 spheno-occipital spheno-occipital
synchondrosissynchondrosis 、、 spheno-ethmoidal spheno-ethmoidal
synchondrosissynchondrosis ))
Growth characteristicsGrowth characteristics :: depthdepth
>>HeightHeight > > WidthWidth
Clinical SignificanceClinical Significance :: Hypoplasia cause Hypoplasia cause
deficiencydeficiency of middle 1 / 3 facemiddle 1 / 3 face
4. Facial Growth and Development 4. Facial Growth and Development
A. Nasomaxillary ComplexA. Nasomaxillary Complex
main Maxillary growthmain Maxillary growth ,, but but
septal cartilage growth conduct the septal cartilage growth conduct the
growth of middle face importantly.growth of middle face importantly.
B. mandibleB. mandible
growth:growth: forward ,downwardforward ,downward
Height > depth > Width Height > depth > Width
5. Maxillary Growth and Development5. Maxillary Growth and Development
A. Passive displacement A. Passive displacement
The cranial base promote the growth of The cranial base promote the growth of
the maxillary, more important for child .the maxillary, more important for child .
B. active growthB. active growth :: depthdepth :: maxillary tuberosity maxillary tuberosity
Alveolar bone growth Alveolar bone growth
Horizontal part of palatine bone growthHorizontal part of palatine bone growth
B. active growthB. active growth :: widthwidth :: median palatine median palatine
suturesuture growth
Buccal surface of maxillary Buccal surface of maxillary
bone hyperplasiabone hyperplasia
Alveolar bone growthAlveolar bone growth
heightheight :: frontozygomatic and frontozygomatic and
zygomaticomaxillary suture growth zygomaticomaxillary suture growth
Orbital floorOrbital floor
reconstructionreconstruction
Basis nasi moves Basis nasi moves
downwarddownward
Alveolar bone growthAlveolar bone growth
C. C. clinical applicationclinical application
• high vault high vault
• Restrict maxillary Restrict maxillary developmentdevelopment
• maxillary protractionmaxillary protraction
• Maxillary arch RPEMaxillary arch RPE
6. 6. Mandibular Growth and DevelopmentMandibular Growth and Development
A. functionA. function :: The only movable bone of Craniofacial The only movable bone of Craniofacial
regionregion 、、 relevant to relevant to
mastication mastication 、、 language language 、、 airway airway maintenancemaintenance 、、 countenancecountenance 。。
B. growth and developmentB. growth and development :: PartitionPartition :: body of mandiblebody of mandible
alveolar processalveolar process
Mandibular Mandibular
ramusramus
functional protuberancefunctional protuberance :: Attachment of muscles and teethAttachment of muscles and teeth
condylar processcondylar process 、、 coronoid coronoid
processprocess 、、 angle of mandible angle of mandible 、、 alveolar processalveolar process
C. The site of growth and mechanismsC. The site of growth and mechanisms
::condylar processcondylar process :: fibrocartilage fibrocartilage ,, growth site growth site 。。
body of mandiblebody of mandible :: outside surface of hyperplasia outside surface of hyperplasia
, , inside the absorption inside the absorption
C. The site of growth and mechanismsC. The site of growth and mechanisms :: Mandibular ramus Mandibular ramus :: posterior margin bone posterior margin bone
apposition apposition ,, anterior margin bone resorption anterior margin bone resorption
alveolar bonealveolar bone :: impact the height of mandibleimpact the height of mandible
C. The site of growth and mechanismsC. The site of growth and mechanisms::
heightheight :: condylar processcondylar process 、、 alveolar bone alveolar bone
growthgrowth
lengthlength : : posterior margin bone apposition posterior margin bone apposition
,, anterior margin bone resorption anterior margin bone resorption
widthwidth :: condylar process growthcondylar process growth ,, Lateral Lateral
mandibular hyperplasia mandibular hyperplasia
D. characteristicD. characteristic :: angle of mandible angle of mandible :: it will be different with it will be different with
age,growth and masticatory function age,growth and masticatory function 。。newborn newborn : : 140 – 160 degree140 – 160 degreeAdults Adults : : 125 degree125 degreethe elderly the elderly : : obtuser obtuser
D. characteristicD. characteristic :: the height of mandibular ramus the height of mandibular ramus :: the the
length of mandibular bodylength of mandibular body
newbornnewborn : : 35 35 :: 100100
adultsadults : : 65 65 :: 100100
mental regionmental region :: protrusion vary protrusion vary
due to the differences of racedue to the differences of race
E. Growth time E. Growth time :: the growth peak ofthe growth peak of mandibular height and length is mandibular height and length is
basically the same with physical growth basically the same with physical growth ,, or a little ealier.or a little ealier. the peak time of adolescent period is the most important in the peak time of adolescent period is the most important in growing period.The time for girls which is 1.5 years earlier growing period.The time for girls which is 1.5 years earlier than boys,come before menarchethan boys,come before menarche .
F. clinical applicationF. clinical application :: change mandibular growth change mandibular growth
and developmenand developmen
functional appliancefunctional appliance
occlusal padocclusal pad
“V”shaped osteogenesis phenomenon Enlow, Proposed the "V"-shaped Principle :
Many facial bone and cranium have a "V" shaped
structure . There are bone apposition in the medial
"V"-shape and bone absorption , lateral. So "V" shape
move from one location to another , while all have
increased in diameter.
When things go wrong
Congenital craniofacial malformations: cleft Congenital craniofacial malformations: cleft lip/palate, syndromes (Apert, Crouzon, lip/palate, syndromes (Apert, Crouzon, etc..), craniosynostosisetc..), craniosynostosis
Non-syndromic craniosynostosisNon-syndromic craniosynostosis TraumaTrauma AnkylosisAnkylosis Juvenile rheumatoid arthritis Juvenile rheumatoid arthritis
When things go wrong
Trauma Blow to one side of Blow to one side of
the mandible may the mandible may fracture the condylar fracture the condylar process on the process on the opposite sideopposite side
pull of the lateral pull of the lateral pterygoid muscle pterygoid muscle distracts the condylar distracts the condylar fragment including all fragment including all the cartilage = the cartilage = resorption occursresorption occurs
五、五、 Theories of growth and developmentTheories of growth and development
It is a truism that growth is strongly influnced by It is a truism that growth is strongly influnced by
genetic factor.In order to understand the etiologic genetic factor.In order to understand the etiologic
processes of malocclusion and dentofacial deformity,it processes of malocclusion and dentofacial deformity,it
is necessary to learn how facial growth is influncend is necessary to learn how facial growth is influncend
and controlled.Exactly what determines the growth of and controlled.Exactly what determines the growth of
the jaws,however,remains unclear and continus to be the jaws,however,remains unclear and continus to be
the subject of intensive research.the subject of intensive research.
• Bone theoryBone theory
It implies that genetic It implies that genetic
control is expressed control is expressed
directly at the level of the directly at the level of the
bone,and therefore its bone,and therefore its
locus should be the locus should be the
periosteumperiosteum 。。
Cartilage theoryCartilage theory
Genetic control is expressed in the
cartilage,while bone responds passively to
being displaced.This indirect genetic
control is called epigenetic.
Soft tissue matrix theroySoft tissue matrix theroy Genetic control is mediated to a large extent
outside the skeletal system and that growth of both bone and cartilage is controlled epigenetically,occurring only in response to s signal from other tissues.
In contemporary thought, the truth is to be found in some synthesis of the second and third theories,while the first ,though it was the dominant view until 1960s,has largerly been discarded.
六、六、 Dentition , occlusal growth and Dentition , occlusal growth and
developmentdevelopment
(一)(一) . Eruption of the primary teeth. Eruption of the primary teeth
1 eruption begins when the root has 1 eruption begins when the root has beenbeen formed.formed.
2 the time of eruption are not 2 the time of eruption are not different in gender different in gender ,, are related to race are related to race and little relation with nutrition.and little relation with nutrition.
3 pairs of the same name erupt in 3 pairs of the same name erupt in the same time.the same time.
六、六、 Dentition , occlusal growth and developmentDentition , occlusal growth and development
(一)(一) . Eruption of the primary teeth. Eruption of the primary teeth 4 the timing and sequece of eruption4 the timing and sequece of eruption
the mandibular central incisors will the mandibular central incisors will erupt first— 6 – 8monthserupt first— 6 – 8months
the maxillary second molars erupt the maxillary second molars erupt at last— 2 -3yearsat last— 2 -3years
maxillary teeth erupt late than maxillary teeth erupt late than Mandibular teeth.Mandibular teeth.
sequence sequence : : I II IV III VI II IV III V
六、六、 Dentition , occlusal growth and developmentDentition , occlusal growth and development
(二)(二) . . Characteristics of primary dentitionCharacteristics of primary dentition
5 flush terminal plane5 flush terminal plane :: Look at the distal aspect of the 2nd Look at the distal aspect of the 2nd
primary molar primary molar Mesial step Mesial step : : 60 - 70%60 - 70%
Mesio stepMesio step
Disto stepDisto step
Classification of Occlusion of the Primary Second Molar
Look at the distal aspect of the 2nd molar Look at the distal aspect of the 2nd molar Flush terminal plane Flush terminal plane Mesial step Mesial step Mesio stepMesio step Disto step Disto step
六、六、 Dentition , occlusal growth and developmentDentition , occlusal growth and development
(二)(二) . . Characteristics of primary dentitionCharacteristics of primary dentition
1 1 anterior teeth spaceanterior teeth space
2 2 Primate spacePrimate space
3 3 shallow overjet ,overbiteshallow overjet ,overbite
4 4 ML side of maxillary primary canine contacts ML side of maxillary primary canine contacts
the DB side of madibular primary canine. the DB side of madibular primary canine.
(三)(三) . mixed dentition period. mixed dentition period
1 The eruption of permanent teeth:1 The eruption of permanent teeth: tooth germ moves in the alveolar bone, and finally comes out
of bone 。the deciduous root absorpted and root of permanent teeth continue to grow during eruption with the height of alveolar bone increasing.
Eruption conditions:
crown fully formed ,roots start to form.
The eruption of the first permanent molar
6years
the eruption of the maxillary lateral
incisor8years
The complete eruption of the
lateral incisor 9years
The eruption of first premolars, mandibular canines , 11years
1 .The eruption of permanent teeth:1 .The eruption of permanent teeth:
Degree in the formation of the root is Degree in the formation of the root is differentdifferent
First permanent molars: 35 - 40% First permanent molars: 35 - 40% Canine: 70%; first premolar: 50% Canine: 70%; first premolar: 50% Second premolar: 50% Second premolar: 50% Second Molar: 25 - 30% Second Molar: 25 - 30%
2 Eruption time and sequence2 Eruption time and sequence
timetime : : 6 — 12years6 — 12years sequencesequence :: U 6 1 2 4 3 5 7U 6 1 2 4 3 5 7
6 1 2 4 5 3 76 1 2 4 5 3 7 L 6 1 2 3 4 5 7L 6 1 2 3 4 5 7 6 1 2 4 3 5 76 1 2 4 3 5 7
3. gap relationships in the process of tooth 3. gap relationships in the process of tooth replacement :replacement :
The whole maxillary deciduous dentition: 68.2 The whole maxillary deciduous dentition: 68.2
The whole maxillary permanent dentition: 74.0 The whole maxillary permanent dentition: 74.0
The whole mandibular deciduous dentition : 61.8 The whole mandibular deciduous dentition : 61.8
The whole mandibular permanent dentition : 64.4The whole mandibular permanent dentition : 64.4
3 space relations in replacement of3 space relations in replacement of teethteeth ::
When the replacement of anterior When the replacement of anterior teeth:teeth:
Gap between deciduous anterior Gap between deciduous anterior teethteeth
Permanent incisor when erupting Permanent incisor when erupting tip forwardtip forward
Deciduous canine displaceDeciduous canine displace
Arch width increaseArch width increase
Replacement of the posterior teeth :Replacement of the posterior teeth :
Premolar erupt more buccally than deciduous teeth Premolar erupt more buccally than deciduous teeth
(Milk canine + the first and second (Milk canine + the first and second deciduous molars )Width> Replacement deciduous molars )Width> Replacement permanent teethpermanent teeth
Leeway SpaceLeeway Space ::
upperupper : : 0.9 - 1.0 mm each side0.9 - 1.0 mm each side
lowerlower : : 1.7 - 2.0 mm each side1.7 - 2.0 mm each side
4 occlusal adjustment in the course of tooth 4 occlusal adjustment in the course of tooth
relapmentrelapment The early replacement: apex to apex relationship between
molars
reasonreason :: a the mesial movement L > Ua the mesial movement L > U b growth to the forward L > Ub growth to the forward L > U
a neutral relationship.
5 5 temporary malocclusion in the mixed dentition years ::
Gap between Maxillary central incisor
Maxillary lateral incisor tilt distally when erupting
Permanent anterior teeth (especially mandibular) crowding mildly
Mild distal molar relationship (early mixed dentition)
Temporary deep overbite (early mixed dentition)
7 years old 9 years old 14 years old
Changes in the axial inclination due to the eruption of the maxillary anterior teeth (Broadbent, 1957).
The factors that affect occlusal buldingPower balance :Power balance : Muscle Muscle Periodontal tissuePeriodontal tissue
Craniomaxillary Growth Craniomaxillary Growth
Genetic Genetic
Nutrition Nutrition
Chronic diseases Chronic diseases
Bad habits Bad habits
Function of factorsFunction of factors
SummarySummary Growth way of craniofacial bones Growth way of craniofacial bones
cellular level: cellular level: HypertrophyHypertrophy HyperplasiaHyperplasia Increased production of extracellular matrixIncreased production of extracellular matrix
Growth of the Cranial Vault and BaseGrowth of the Cranial Vault and Base Growth of Maxilla (Nasomaxillary Complex) Growth of Maxilla (Nasomaxillary Complex) Resorption Resorption 、、 AppositionApposition
Growth of MandibleGrowth of Mandible (( LengthLength 、、 WidthWidth 、、 HeightHeight )) Theories of Growth ControlTheories of Growth Control
BoneBone CartilageCartilage The soft tissue matrix in which the skeletal elements are embedded - 60’s The soft tissue matrix in which the skeletal elements are embedded - 60’s
“Functional Matrix Theory” by Moss“Functional Matrix Theory” by Moss
Growth of OcclusionGrowth of Occlusion
Questions
the methods of Craniofacial Growth and the methods of Craniofacial Growth and Development?Development?
The development of maxilla and mandible , how to The development of maxilla and mandible , how to complete in three dimensions?complete in three dimensions?
What is leeway space and what is its clinical What is leeway space and what is its clinical significane ?significane ?
The manifestationThe manifestation of temporary malocclusion ,they of temporary malocclusion ,they can be adjusted at the process of growth and can be adjusted at the process of growth and development ,why ?development ,why ?