Chapter 10: Growth and Development/Management of the Developing Occlusion Flashcards
Two types of bone formation
Endochondral
Intramembranous
Endochondral bone formation
Bony replacement of cartilaginous precursors
Cranial bse and condyle of the mandible
Less modifiable in context of dentofacial orthopedics
Intramembranous bone formation
Secretion of bone matrix without cartilaginous precursors
Facial bones (maxilla, body of mandible)
More modifiable in context of dentofacial orthopedics
Does bone apposition occur in osteogenic areas under pressure or under tension?
Under tension
Growth of the Cranial Vault
Formed by intramembranous ossification
Apposition of new bone primarily at sutures
Remodeling on inner and outer surfaces of bones to allow for changes in contour
Growth of the Cranial Base
Formed by endochondral ossification
Bony replacement primarily at synchondroses
Spheno-occipital considered principal growth cartilage of cranial base and only one remaining active in childhood growth period
Growth of the Maxilla
Formed by intramembranous ossification
Apposition in superior and posterior sutures of maxilla
Resorption on anterior surface of maxilla
Balanced apposition and resorption
Appositional growth occurs up and back against cranial base with growth expressed down and forward
Growth of the Mandible
Formed by endochonral ossification at condyle, intramembranous at body
Endochondral replacement at fibrocartilage of condyle
Appositional growth predominates along posterior border of ramus, remodeling along anterior border
Appositional growth occurs up and back against glenoid fossa, with growth expressed downward and forward
How much sooner do females reach skeletal maturity compared to males?
2 years earlier on average
Female growth spurt
Starts at approximately 10.5-11 years
Peaks 14-18 months later (12-13 years)
Complete by about 13.5-14 years of age
Male growth spurt
Starts at approximately 12.5-13.5 years
Peaks in 18-24 months (14-16 years)
Complete by about 17-18 years of age
Hypodivergent/brachyfacial facial form
Posterior face height proportionately greater than anterior face height
Flat mandibular plane, pronounced overbite
Hyperdivergent/dolichofacial
Anterior vertical facial growth greater than posterior condylar growth
Steep mandibular plane with open bite tendency
Vertical dimension growth
Nasion-menton
70% complete by age 3; 90% by adolescent growth spurt
Transverse dimension growth (facial width)
The least amount of change of any facial dimension
Upper face width increases during childhood and adolescence with greatest rate observed between 2-6 years
Lower face width 85% complete by time first molars erupt
Anteroposterior dimension growth (facial depth)
Longest growing facial dimension
Greater mandibular increments allow profile to change from convex in childhood to straighter adult profile
Airway compromise/mouthbreathing impact on growth
May compromise facial growth
Increase vertical orientation
Similar occlusion changes as with extraoral habits
Management of mouthbreathing
Distinguish from extraoral habits
If airway related, refer to ENT assessment for allergy management, tonsillectomy/adenoidectomy followed by palatal expansion
Is there a recognized or specific standard for what type of diagnostic records are necessary for orthodontic problems?
No
General agreement that proper assessment includes questionnaire of patient, examination, as well as diagnostic records
2016 AAO list of pretreatment unaltered diagnostic records needed for comprehensive orthodontic treatment
Intra and extraoral images
Dental models of maxillary and mandibular arch
Intraoral and/or panoramic radiographs
Cephalometric radiographs, with CBCT used as alternative when necessary
Periodic radiographic assessment, such as panoramic, is recommended at what intervals during ortho treatment?
6-12 months
Recommended due to major problems such s external apical root resorption
Ceph: Maxilla to cranium
SNA
A point to Nasion
Ceph: Mandible to cranium
SNB
Pogonion to Nasion
Ceph: Maxilla to mandible
ANB
Mx-Mn length difference
Ceph: incisor position
Upper incisor to cranial base (Frankfort horizontal, S-N)
Lower incisor to mandibular plane (IMPA)
Upper and lower incisors to facial lines (NA, NB)
Ceph: growth direction
Mandibular plane angle (FMA)
Y-axis to cranial base
Lower face height
Ceph: soft tissue profile
Angle of facial convexity
Lip profile to E-line
Nasolabial fullness
Evaluating a Ceph
Head orientation: Frankfort horizontal plane should be perpendicular to vertical edge of film
Chin position: nasion to pogonion line (facial plane) should be parallel with vertical edge of film after growth is complete
Maxilla position: NA line should be parallel with vertical edge of film
Mandibular plane: Go-Gn should intersect with cranial outline at occiput
Maxillary incisor position: long axis should be tangent with orbitale
Mandibular incisor position: long axis should show proclination
Facial height: Upper face height (N-ANS) should be equal to lower face height (ANS-Me)
Eruption sequence of primary teeth
A-B-D-C-E
Both arches are this way
Primary teeth eruption timing (broad)
Erupt from 8 months (lower central incisors) to 30 months (upper second primary molars), S.D. of 3 months
By what age is primary dentition occlusal relationship established?
36 months
Baume Type I
Spaced primary dentition
Approximately 2/3 of kids
Baume Type II
Non-spaced primary dentition
Approximately 1/3 of kids
Primate Spaces
Mesial to upper primary canines in maxilla
Distal to lower primary canines in mandible
Molar terminal plane relationships frequencies
Mesial step: 14% incidence
Flush terminal plane: 76% incidence
Distal step: 10% incidence
Incisor relationships
Overbite: 2mm (30-50% vertical overlap)
Overjet: 0-3mm
Early Mesial Shift
Closing of interdental space between molars prior to eruption of permanent molars
Occurs due to eruption path of permanent molars which guide on distal roots of primary second molars
What age does early mesial shift occur?
Approximately 4 years of age
Eruption timing of permanent teeth (broad)
Permanent teeth erupt beginning at 6 years of age and is generally complete by 12 years of age upon eruption of maxillary canines and/or second permanent molars
Permanent teeth eruption sequence
Maxilla: 6-1-2-4-5-3-7
Mandible: 6-1-2-3-4-5-7
*Permanent mandibular arch is the only one that erupts in order of position (with exception of first molar of course)
What is the buccal segment in the transitional dentition?
Primary teeth that remain (C-D-E)
Incisor liability
Permanent incisors are larger than primary incisors
- 1mm in maxilla
- 1mm in mandible
Intercanine width expansion
Upper width: mean of 3.0mm
Lower width: men of 2.4mm
More labial eruption of permanent incisors increases arch perimeter
Permanent incisor relationships
Typically 1-2mm of lower incisor “crowding”
No spacing or crowding in upper incisor segment
“Ugly duckling” stage with splayed maxillary incisors considered normal
Overjet: range 0-3mm
Overbite: range 0-5mm
Permanent molar relationships - Class I
Considered ideal
Maxillary first molar mesial cusp in mandibular molar buccal groove
Occurs when primary molars are mild mesial step
Permanent molar relationships - End On Class II
Majority of mixed dentition occlusions
Occurs when primary molars are flush terminal plane
Permanent molar relationships - Full Class II
Maxillary first molar mesial cusp forward in embrasure between lower first molar and second primary molar or second premolar
Occurs when primary molars are distal step
Permanent molar relationships - Class III
Maxillary first molar mesial cusp distal to lower first molar buccal groove
Occurs when primary molars are more severe mesial step
Must discriminate from pseudo-class III with forward shift of mandible to exaggerate discrepancy
Leeway space
Size differential between primary C-D-E segment and permanent 3-4-5 segment
Upper leeway space: 0.9-1.1mm per quadrant
Lower leeway space: 1.7-2.4mm per quadrant
Late mesial shift
Mesial shift of permanent first molars into leeway space when second primary molars exfoliate Contributes to correction of typical flush terminal plane relationship into class I
Closure of maxillary diastema
Maxillary diastemata in mixed dentition typically close on eruption of maxillary canines
Ideal primary dentition occlusion
Flush terminal plane or mesial step molar with class I canines
Generalized spacing including primate spaces
2mm overjet, 2mm overbite (30%)
How does primary spcae affect rowding outcome in mixed dentition?
Spacing 3-6mm: no transitional crowding
Spacing less than 3mm: 20% incisor crowding
No spacing: 50% incisor crowding
Crowded primary teeth: 100% incisor crowding
Mesial step indication for permanent molar relationship
68% convert to class I 19% convert to class III Usually reflecting class III skeletal malocclusion
Flush terminal plane indication for permanent molar relationship
56% shift to class I 44% stay end-on or class II 15% reflect skeletal malocclusion involving mandibular retrognathia Canines also demonstrate class II positioning with pronounced overjet of 6mm+
DIstal step indication for permanent molar relationship
Usually results in full class II Some shift to end-on class II molars
Canine relationship in primary and permanent dentitions
Best predictor of sagittal relationship into permanent dentition Mesial step canines usually result in class I Distal step/end-on usually result in class II Excessive mesial step with incisor crossbite usually results in class III
Influences on permanent molar transisition
Primary molar terminal plane relationship
Primary spacing which may be closed by “early mesial shift” as permanent molars erupt
Leeway space, which allows “late mesial shift”
Mandibular growth and differential growth may affect relative A-P positioning
Consequences of premature loss of primary incisors
Space loss unlikely if primary canines erupted into occlusion
Replacement of primary incisors is not required to maintain space
-elective for cosmetic issues, may be beneficial for language development
Consequences of premature loss of primary canines
Usually due to ectopic eruption of permanent laterals
-indicator of significant TSALD
-beyond simple space maintenance - space analysis required
Premature loss sometimes secondary to trauma/caries
-no space maintenance generally indicated except to maintain midline symmetry
Consequences of premature loss of first primary molars
Space loss considered negligible if first primary molars lost after first permanent molars erupt into occlusion
Space maintenance indicated if first permanent molars not erupted or are in active eruption
-usually unilateral fixed appliances (band/loop)
Consequences of premature loss of second primary molars
Space loss in either arch most dramatic in association with eruption of first permanent molars
Dimensional space loss greater in maxillary arch
-maxillary 1st permanent molars move forward and rotate around palatal root
-mandibular molars show mesial and lingual crown tipping
If first permanent molar is not erupted or active eruption
-distal shoe, reverse band and loop, removable appliance
If first permanent molar is erupted
-band and loop, bilateral space maintainers
Band and loop
- replacement for loss of single tooth
- can be forward or reverse
- may need to be replaced on exfoliation of primary canine (especially in mandible)
Crown and loop
Use is similar to band and loop with loop soldered directly on crown
Distal Shoe
Used for replacement for loss of primary second molar when permanent molar hasn’t erupted
Narrowest (most specific) indications for use
Most contraindications for use
Lower lingual holding arch
Replacement for loss of multiple teeth in mandibular arch
May also be used to prevent lingual tipping of incisors following premature loss of canines
May interfere with eruption of permanent incisors if placed prior to eruption
Nance appliance
Replacement for loss of multiple teeth in maxillary arch
Acrylic button provides resistance to mesial movement, but can accumulate plaque
Transpalatal or Goshgarian arch
Replacement for loss of multiple teeth in maxillary arch
Considered less efficient than Nance, but can be used to create minor orthodontic tooth movement
When is bilateral space maintainer advised?
Once first permanent molars are erupted
Important to control molars and allow buccal segment transition due to eruption patterns and potential loss of abutments
Removable appliances
Acrylic appliances
Replacement for loss of multiple teeth in either arch
May be used instead of distal shoe for replacement of primary second molar
Regaining lost posterior space
Indicated if it simplifies, minimizes or eliminates subsequent orthodontic treatment
- maxillary regaining: headgear, fixed molar distalizing appliances, removable appliances
- mandibular regaining: lip bumper, active lingual arch, removable split-saddle
Overview of preventive orthodontic treatment
To preserve and maintain normal relationships in developing occlusion through prevention of oral disease, restorative care and space maintenance
approximately 50% of children would benefit from guidance and interceptive procedures beyond “preventive” interventions
Overview of limited orthodontic treatment
Ortho treatment with a limited objective, not necessarily involving the entire dentition
It may be directed at only existing problem, or only one aspect of a larger problem in which a decision is made to defer or forego more comprehensive therapy (ADA CDT 2016)
Overview of interceptive orthodontic treatment
Extension of preventive orthodontics that may include localized tooth movement
May occur in primary or transitional dentition
Includes redirection of ectopically erupting teeth, correction of crossbite or recovery of space loss
May reduce severity of malformation when initiated during incipient stages
Conditions considered for minor tooth movement procedures within the context of interceptive orthodontic treatment
Oral habits
Dental/functional anterior crossbites
Posterior crossbites
Ectopic eruption of permanent first molars
Recognition and correction of dental anomalies
-identification and elimination of anomalies and effects
-supernumerary teeth, missing teeth, tooth size/shape anomalies, ankylosis, pathologic lesions, etc.
Space supervision overview
Encompasses treatment procedures derived from clinical judgment where clinician determines that a patient’s occlusion will have a better chance of obtaining optimum development with supervised intervention (Moyers)
Guidance of eruption (space supervision)
Procedures that influence eruptive patterns of permanent teeth
When overall space is adequate to accommodate a normal complement of permanent teeth with acceptable esthetics and functions (Hotz)
Goals of space supervision/guidance of eruption
Improved esthetics/incisor integrity
Dentitional development without functional problems
Optimal permanent tooth eruption
Avoid unnecessary extraction of permanent teeth
-optimal use of leeway space and arch perimeter
Clinical procedures in space supervision
Preventive and restorative dentistry
-preserve arch integrity and arch perimeter
Space maintenance
-stabilize molar and anterior tooth positions to prevent loss of arch length
Disking of primary teeth
-reduction of mesiodistal primary tooth structure to enhance adjacent permanent tooth alignment through timely use of leeway space
Selective extraction of primary teeth
-extension of disking concepts in timely removal of primary teeth to enhance permanent tooth eruption and alignment positioning
Minor tooth movements
-biomechanical tooth movements to return or direct developing occlusion to normal
-minimal or simple appliance therapy over short interval
Non-nutritive digit sucking habits prevalence
Normal at early age
50% of children with NNS habit will discontinue between 24-28 months of age
Incidence rate of 10-15% at age 5
Do digital habits or pacifier habits last longer?
Digital
Both produce similar effects if persist past 4 years of age
Consequences of NNS
Anterior openbite Distorted incisor eruption Increased overjet Proclined upper incisors Linguoversion of lower incisors Posterior crossbite with constricted maxilla Possible class II relation
When should you consider intervention to NNS?
Prior to eruption of permanent anterior teeth approximating age 5 to 6 years if NNS habit persists and patient-parent indicate understanding of need to stop
- use “gentle persuasion” as beginning treatment; behavior modification can be successful
- cribs, rakes, “bluegrass appliance” are choices for fixed therapy to “help” child quit
Anterior Crossbites in Primary Dentition
Must distinguish between true class III versus pseudo-class III
Pseudo-Class III (primary)
Incisal and canine interference produces anterior shift of mandible on closure
Treatment directed at advancement of maxillary incisor segment to eliminate interference
Fixed or removable maxillary appliances with finger or sweep springs to advance incisors
Treatment most frequently considered limited
True Class III (primary)
Presents classic skeletal and dental patterns with retruded maxilla, prognathic mandible, “adult” concave profile, retroclined lower incisors
Treatment directed at dentofacial orthopedic changes to correct skeletal malocclusion
-reverse pull headgear/facemask to encourage maxillary growth
-chincup to discourage mandibular growth
-treatment most frequently considered interceptive with expectation of future comprehensive treatment
*both true and pseudo-class III may require concurrent maxillary expansion
Functional posterior crossbite in primary dentition
> 90% of primary dentition posterior crossbites express functional shift
Origin usually bilateral maxillary constriction
-decreased maxillary intercanine width with vertically oriented primary canine interferences
-first contact position with coincident midlines exhibits typical transverse end-on buccal segment cusp-to-cusp occlusion
-shift of mandible on closure results in appearance of unilateral crossbite
-crossbite involves entire buccal segment >90% CDE, 2/3 include lateral incisor
Asymmetric midline/chin position associated with asymmetric growth pattern
Basic treatment of posterior crossbite in primary dentition
Fixed rapid palatal expanders (RPE of Haas, Hyrax) - over 90% success
Fixed archwire expanders using “slow, low-force” approach (w-arch, quad helix) over 90% success
Removable Schwartz plate - type appliances - 70% success
Bilateral posterior crossbite in primary dentition
True maxillary skeletal constriction with bilateral buccal segment crossbite, midline symmetry and no notable shift of mandible
2-3% of posterior crossbites in children
Often associated with dolichofacial skeletal vertical growth, openbite malocclusion, compromised airways, mouthbreathing
Basic treatment is maxillary expansion
-long term management generally requires multi-phased comprehensive approach
Ectopic eruption of first permanent molars
Incidence 2-3% in maxillary arch, rare in lower
Self-correction 2/3 of cases
Consequence: if not corrected by age 7, can see supereruption of mandibular molar
Treatment of ectopic eruption
Observation - 2/3 correct
Rare for self-correction after age 7
Once mandibular molar is level with occlusal plane, treatment is indicated
Brass ligature wire, elastic separators, careful disking of second primary molar distal ledge
Humphrey appliance: fixed palatal archwire from E’s with distalization spring to first molar
Halterman appliance: fixed palatal archwire from E’s with distalization elastics to bonded button
Mandibular incisor crowding
Considered normal
Average crowding is -1.6 +/- 1.0mm after incisor eruption complete
After lateral incisor eruption, what you see is what you get
If crowding is excessive (beyond 2-3mm), plan long-term arch development approach versus serial extraction
If crowding can be accommodated by controlled use of leeway space, intervene
Considerations for use of leeway space
Periodontium - thin labial gingiva or mucogingival defect
Profile and incisor position - incisors most stable where “naturally” found
Vertical relationships - extractions deepen bite, non-extractions open bite
Premature exfoliation of primary teeth
Interventions for relieving incisor crowding - disking of primary canines
- can allow 1-2mm of space per side (must go subgingival)
- indicated with less than 3-4mm of incisor crowding
- indicated when laterals erupting to alignment with eruptive width changes complete
- indicated when primary canine roots are intact
- preferred option, especially in deepbite patterns to maintain vetical support
Interventions for relieving incisor crowding - extraction of primary canines
- to enhance arch symmetry, coincident midlines and incisor integrity when incisor liability is greater than 4mm
- recommended with asymmetric ectopic loss of primary canine producing a midline shift (extract contralateral canine)
- frequently step 1 of serial extraction program especially in dolichofacial openbite
- strongly recommended to place LLHA as extraction of primary canines reduces arch perimeter and can lead to lingual collapse of incisors, deep bite, increased overjet
Interventions for relieving incisor crowding - edgewise appliance
-use of Edgewise 2X4 appliance to position incisors and molars toward favorable class I relationships with incisor integrity, midline coincidence and normal overbite and overjet
To extract or not to extract? (serial extractions)
Facial type is a critical factor in decision
- Brachyfacial/deepbite: prioritize arch development/expansion
- Dolichofacial/openbite: extraction protocol more likely
Lower lingual holding arch benefits
“Late” supervision of leeway space - use of LLHA with selective extraction of primary molars reserves the “E-space” and controls late mesial shift
- timely placement of LLHA allows distal eruptive positioning of premolars and canines (1.5mm distal placement) and provides 2-4mm of space for relief of incisor crowding
- applicable in 2/3 - 3/4 of children with normal crowding patterns
- initiation of edgewise therapy to position incisors and molars toward class I relationships while controlling leeway space also applicable in timing with loss of second primary molars
Ankylosed teeth - most common tooth?
Lower first primary molars
Followed by upper first primary, lower second primary, and upper second primary
Does resorption of ankylosed teeth occur?
Resorption of ankylosed molars usually proceeds in normal mode with 95% of premolars erupting into proper occlusion with normal periodontal health and alveolar bone height
Most common sequela is simply delayed transition as to timing
Sequela of ankylosed teeth
Static retention of ankylosed tooth often results in clinical “submersion” and supreeruption of opposing tooth
Can result in tipping of adjacent teeth with accompanying space loss
Second primary molars are of much greater significance to arch integrity than first primary molars - especially when ankylosis occurs before eruption of permanent molars
Management/intervention of ankylosed teeth
May monitor early on, as tooth often shows normal exfoliation
Mesiodistal width and occlusal relationships may be maintained with composite build-ups, stainless steel crowns
Eventual treatment may involve extraction later if exfoliation is delayed or deflected eruption of permanent successor occurs
May need space maintenance if indicated unless sufficient crowding to justify serial extraction plan
Supernumerary teeth Incidence
Reported in up to 3.6% of children
Occur 10x more in maxilla
Occurs in boys 2x more than girls
Mesiodens: 80% single, 20% two or more
-most palatally positioned (90%)
-75% need surgical extraction as they remain impacted
Can be responsible for delayed eruption of permanent teeth, over-retention of primary teeth, displaced teeth, diastemas, abnormal root resorption, dentigerous cysts, malocclusion
Supernumerary Teeth - Treatment
Remove when no harm will come to permanent teeth
-prefer to wait until 1/2 to 2/3 of root development of adjacent permanent teeth
-patient age and potential for cooperation also factors in delaying surgical intervention
-watchful waiting allows time for possible eruption of supernumerary, avoidance of surgical exposure
When removed, exposure of permanent teeth with provision of eruption channel recommended
-up to 80% of permanent teeth spontaneously erupt after removal of supernumerary
-ortho treatment often necessary to make room and position properly
Comprehensive Orthodontic Treatment - definition
“Includes a coordinated diagnosis and treatment leading to the improvement of a patient’s craniofacial dysfunction and/or dentofacial deformity which may include anatomical, functional and/or esthetic relationships. Treatment may utilize fixed and/or removable orthodontic appliances and may also include functional and/or orthopedic appliances in growing and non-growing patients. Adjunctive procedures to facilitate care may be required. Comprehensive orthodontics may incorporate treatment phases focusing on specific objectives at various stages of dentofacial development.” ADA CDT 2016
Crowding/Malalignment in Permanent Dentition
Depending on amount, space in permanent dentition is gained via protrusive movement of anterior teeth, retrusion of posterior teeth, arch expansion or tooth mass reduction (extraction or IPR)
Maxillary Canine Eruptive Displacement Incidence
Usually palatal displacement in 1-2% of population
Females affected 3 times more than males
More common is mesiolabial displacements secondary to segmental crowding - up to 10% of children
-labial and palatal malpositioning associated with atypical resorption of permanent incisors
-ectopic eruption or impaction may be associated with constricted maxillary intercanine width, agenesis or microdontia of lateral incisor, and arch length deficiency
Early recognition of maxillary canine eruptive displacement
Approximating 10-12 years, palpation and radiographic evaluation with periapical or panoramic images
Clinical signs: lateral incisor distal inclinations pronounced, small maxillary lateral, primary canines not mobile, eruptive bulging of canines atypical
Treatment intervention of maxillary canine eruptive displacement
Interceptive: excessive canine mesial orientation may be redirected to more distal and vertical eruption path through removal of primary canine when permanent canine has 2/3 root development
-if the displaced permanent canine overlap of adjacent lateral incisor is not beyond the midline long axis, chances for canine normal repositioning after primary canine extraction is 85-90%
-if overlap is beyond lateral long axis, successful repositioning in 60%
Comprehensive: edgewise appliances to ensure space for positioning and establish anchorage for ortho eruption: uncover canine, engage with attachments
Congenitally missing permanent teeth
Most common = lower second bicuspids
-then upper lateral, upper second premolar
Incidence of missing permanent teeth is about 4%, no gender difference
Affects two or more teeth in about half of cases, frequently symmetrical pattern
Consideration: cone-shaped teeth characteristically seen in association with missing teeth
Consequences and considerations of congenitally missing teeth
Important to consider long-term arch alignment
First decision is whether to keep or extract the primary tooth
Space closure usually desirable for bilateral missing teeth
For single missing teeth, usually try to maintain space until future prosthetic management
Treatment options for missing permanent teeth - missing laterals
Noncrowded arches, class I/II: Maintain primary lateral and/or manage and open space orthodontically with long-term plan for implants or Maryland bridge
Crowded arches, class II: Enhance movement of permanent canines forward into lateral position with “early” extraction of primary laterals, latera orthodontic alignment for “canine replacement”
Treatment options for missing permanent teeth - missing second premolars
Noncrowded arches, class I/II: Maintain primary molar and/or manage space with long-term plan for implants
Crowded arches, class III: Enhance movement of permanent first molars forward with “early extraction of primary second molar
Important to keep in mind that case reports exist showing second premolar tooth germ development/calcification not until as late as 10 years of age
Overview of dentofacial orthopedics
Biomechanical treatment directed at altering the relationships of the jaws and the activity patterns of orofacial muscles to effect changes in facial proportions
Rationale of dentofacial orthopedics
Objectives of facial and dental esthetics with functional harmony can rarely be achieved without compromise unless basal arch relationships are in orthognathic position with Class I molar and canine relationships, acceptable overbite and overjet, coordinated transverse archforms
Significance of dentofacial orthopedics
To modify growth, one must treat during active growth periods
More severe discrepancy, earlier the treatment
Class II Division 1 (most common features)
Normal maxilla Notable mandibular retrognathia (85%) Vertical growth tendency Narrowed upper arch Good lower arch Full class II, ANB > 6 degrees
Class II Division 2 (most common features)
Normal maxilla Mild mandibular retrognathia Strong chinpoint Deepbite growth tendency Broad archforms End-on class II, ANB < 6 degrees
Class III (most common features)
Combination of maxillary retrognathia, mandibular prognathia Negative ANB Vertical growth patterns Transverse maxillary deficiency Retroclined lower incisors
Anteroposterior Class II Malocclusion > Protrusive maxilla > directed headgear
Promote restraint of maxillary dental and skeletal forward and vertical development
Distalize upper arch and allow normal mandibular growth
Cervical Pull Headgear
For Anteroposterior class II malocclusion
Optimize molar distalization, redirect vertical development, influence maxillary skeletal growth, decrease overbite
Increases lower face height
High Pull Headgear
For anteroposterior class II malocclusion Promotes horizontal and bodily dental movement of molars, distalization effects are minimal Restrains vertical/forward development of molars and downward/forward growth of maxilla Minimizes lower face height changes to reduce bite opening
Indications for extraoral headgear beyond maxillary protrusion
Retraction will not compromise nasolabial profile
Distalization of buccal segments to gain arch length and optimize class I molars
Anchorage support for incisor retraction
Symmetrical AP positioning
Active growth: on upward slope of growth curve
Arch expansion desirable to enhance forward movement of mandible
Cooperation/understanding of patient/family
Anteroposterior class II malocclusion > retrusive mandible > funcational appliances
Promote mandibular growth by advancing with protrusive bite appliance, restrain maxillary forward growth
Holding mandible forward produces reactive forces on adjacent structures and these reactive forces combine with growth of mandible
-move upper teeth backward, move lower teeth forward, and restrain maxillary skeletal growth
Conditions favorable for use of functional appliances
Treatment carried out during periods of active growth
Favorable growth pattern (contraindicated in dolichofacial growth because they increase lower face height)
Nasal airway not compromised
Symmetrical dental arches
Cooperation
Examples of functional advancement appliances
Bionator/orthopedic corrector Activator Frankel Herbst Mara
Anteroposterior Class II Malocclusion with acceptable AP skeletal relationship
Promote corrective changes by restraining/distalizing upper dentition, protracting lower dentition
Class II elastics (requires Edgewise appliance)
Headgear, distal jets, springs
May incorporate selective permanent tooth extractions to camouflage AP discrepancy
Class II Div 2 usually want to avoid extractions (will deepen bite)
Anteroposterior Class III malocclusion -> retrusive maxilla - > facemask/reverse pull headgear
Protract maxillary complex
Extraoral reverse-pull headgear (facemask) redirects or enhances maxillary growth with forward protraction
Expand maxillary arch to “unlock”occlusion for enhanced maxillary forward movement
May eliminate abnormal muscle function
Application of facemask therapy in primary and early mixed dentition
Shown to produce most dramatic results for class III correction in shortest time period Treatment concurrent with incisor eruption to optimize growth and occlusal relationships
Results from reverse-pull headgear
Mesial movement of maxillary molars/incisors (3mm per year)
Shearing effect at sutures to maximize displacement of maxillofacial complex
Increased lower face height
Increases lingual uprighting of lower incisors
Anteroposterior Class III Malocclusion - > protrusive mandible -> chincup therapy
Restrain mandibular growth
Restraint of true mandibular growth is not documented by long-term studies
Primarily redirect mandibular growth direction more vertically
Usually contraindicated as it worsens dolichofacial growth pattern
Transverse Arch Expansion
Basal orthopedic maxillary expansion involving sutural separation achieved before locking of palatal sutures around age 12 Almost all class III patients require this Can benefit about 50% of class II Div I malocclusions
Posterior Crossbite In Permanent Dentition
Difficulty of creating sutural expansion while minimizing dental tipping and alveolar bone damage (since sutures are fused)
Surgically assisted rapid palatal expansion may need to be considered
Anterior Openbite with Extraoral Habit
Prolonged digit or pacifier sucking habits
Flaring of maxillary incisors/lingual inclination of mandibular incisors -> increased overjet
Anterior openbite
Distortion of maxillary alveolar process
Abnormal muscle activity
Tongue thrust - almost always occurs in response to openbite
Perioral dysfunction: lip and mentalis habit with tongue thrust and overjet/openbite
Mouth breathing
Treatment of Anterior Open Bite
Eliminate habit and control tongue thurst
OK to watch before age 4-5, but as incisor transition period approaches, more aggressive intervention needed
Psychological rewards: first choice at 4-6 years of age using reward program for three months
Mechanotherapy: palatal crib appliance
-crib reminds child not to engage in habit and promotes incisor self-alignment
-planned for six months wear; habit usually ceases within weeks
Myofunctional therapy: only if associated speech problems
Deep Overbite
General treatment strategy to extrude posterior teeth and allow rotation of mandible downward
Combination of maxillary molar extrusion via cervical headgear or orthopedic functional appliances, intrusion of anterior teeth; may require orthognathic surgery
Often associated with Class II Div 2
One of the more difficult orthodontic problems to correct and retain
Contemporary Treatment - Clear Aligners
Small movements of teeth using vacuum formed plastic aligners
Effective for mild to moderate problems
Best used with other auxiliary ortho appliances
Minimizes plaque accumulation, tissue inflammation and gingival recession
Not good at translational movement
Lag time in initiating therapy longer than brackets due to manufacturing process
Compliance can be an issue in teens
Aligners may cost more for fabrication, but reduced chair time and total expense may be comparable
Temporary Skeletal Anchorage Devices (TADS)
Miniscrews and miniplates
Miniscrews do not require surgery, miniplates do
Miniscrews are cheaper, less risk
Miniscrews used for immediate loading, miniplates used for patients with severe malocclusions
Both utilized for dental changes in all three planes of space
Orthodontic treatment and Sleep Apnea
Prevalence of snoring: 3-27%; prevalence of OSA 1-10%
Ortho treatment includes mandibular advancement or maxillary expansion
Ortho treatment may reduce pediatric snoring and OSA
Only small number of studies conducted to date, more data needed
Ortho for Patients with SHCN
75% of patients with disabilities would benefit
Increased frequency of overjet, posterior crossbite and anterior openbite
Downs: abnormal tongue position, openbite, class III, posterior crossbite
CP: class II malocclusion and diastemas
Autism: increased frequency of missing teeth, spacing, diastema, anterior crossbite, class II, open bite
Parents usually motivated to help in oral hygiene and improve esthetics
53% of orthodontists feel prepared to treat patients with craniofacial anomalies, but only 35% are prepared to treat patients with special needs/dev delays
Considerations for Ortho in Patients with SHCN
Gag reflex
Uncontrolled movements
Ability to submit to prolonged dental procedures (ability to sit still)
Drooling
Need for procedures under general anesthesia
Contraindication: poorly controlled seizure disorder
Need to have realistic treatment goals adapted to patient’s needs/ability
Outcomes of Ortho in Patients with SHCN
Parents of children with disabilities report higher social acceptance and integration after treatment and higher satisfaction with results than parents of healthy children
No difference in overall treatment time for children with craniofacial anomalies
