4B Flashcards
(127 cards)
1
Q
Growth Modification
● Female at
A
15 is post adolescent (16 for males) - can’t use RPE bc midpalatal suture fused
2
Q
Treatment options for Skeletal malocclusion ⇒
A
growth modification, camouflage, & surgical treatment
3
Q
Sites of facial growth:
● Growth centers ⇒
● Growth sites ⇒
A
nasal septum; synchondrosis
sutures; condyle; alveolus
4
Q
Sutures & alveolus have good ——-; synchondrosis have ——-; condyle/nasal septum ——-
A
modifiability
poor
questionable
5
Q
Requirements for growth modification:
A
● Growth patient
● Ability to affect sutures
● Condyles require function (including translation)
● Alveolus require teeth (or a functioning unit)
6
Q
Periods of rapid growth make modification process easier:
● Males
● Females
A
12-14 (13-15) y/o
10-12 y/0
7
Q
Somatic & facial growth ⇒ loosely related
A
in growth timing
8
Q
● Growth has variable rates
A
(fastest from 0-2 years & adolescent growth spurt)
9
Q
● Noses ⇒
A
males have more nose growth than females (esp. post-adolescence)
10
Q
● Lip competence ⇒
A
increases with age (lips grow vertically more than skeleton)
11
Q
● Lip protrusion ⇒
A
decreases with age (lips thin with age)
12
Q
● Chin ⇒
A
Males get more chin button than females
13
Q
● Late growth:
A
○ Maxilla downward growth & Mandible forward growth post-adolescence
14
Q
○ Women ⇒ more —— growth; Men ⇒ more ——— growth
A
maxillary
mandibular
15
Q
Methods for growth assessment:
A
● Ht. & wt. Measurements; secondary sex characteristics; menarche (occurs after peak growth spurt)
● Cervical vertebrae & cephalometric XR
16
Q
US population ⇒ Class II malocclusion ——-; Class III malocclusion =======
A
15-20%
3-5%
17
Q
General dentists can diagnose skeletal problems by
A
profile analysis & assessing dental relationships
18
Q
● Profile analysis difficult for
A
young children (esp. <6 y/o), Class III, & when vertical problems present (profile analysis possible, just need to be careful)
19
Q
● Dental relationships:
○ Provides good clues in
A
Class II & III malocclusion (esp. when profile agrees)
■ Ie. increased overjet with class II molars & convex profile → likely Class II problem
○ Can be deceptive when habits affect the teeth
■ Ie. anteriors don’t coincide with posteriors in giving info about malocclusion type
20
Q
Indications for growth modification ⇒
A
growing patient with mild-moderate skeletal problems
21
Q
Indications for growth modification
A
● Severe problems need surgery
22
Q
Indications for growth modification
Possibilities for growth modification:
● Maxilla →
A
easier to modify than mandible
23
Q
Indications for growth modification
Possibilities for growth mod
● Anteroposterior →
A
possible
24
Q
Indications for growth modification
Possibilities for growth mod
● Vertical →
A
hardest to modify; last dimension to stop growing
25
Indications for growth modification
Possibilities for growth mod
● Transverse →
first dimension to stop growing (why maxillary constrictions need to be treated early)
26
Types of growth modification:
● Ultimate size changes (stimulation/retardation)
● Timing changes (acceleration/deceleration) - no overall change in size
● Redirection
27
Classic one phase growth modification with comprehensive orthodontic care
● Ideal to modify growth & provide comprehensive ortho at the same time - one phase treatment
28
Class II maxillary protrusion ⇒ Treat with
headgear (restricts maxilla & allows for mandibular growth)
29
● High-pull headgear ⇒
force directed posteriorly & superiorly
30
● Cervical pull ⇒
force directed posteriorly & down
31
● Combination headgear ⇒
force directed more horizontal
32
● Example results of headgear pt:
○ maxilla still grows downward, but NOT forward
| ○ Mandible grows downward & forward, becomes more prominent
33
Class II mandibular retrusion:
| ● Treatment with
functional appliances
○ Brings mandible forward, unloading condyle & allowing mandibular growth
○ Forces push mandible forward & maxilla backward → upper teeth retrude; lowers protrude
34
● Example of functional appliance pt:
○ Mandible comes forward more than downward
| ○ Maxilla maintains normal downward growth, but less forward growth
35
Class III maxillary retrusion
| ● Treatment with
facemask - reverse pull headgear
36
○ Can expect-------mm of forward maxilla growth in year
2-3
○ Mandible rotates down & back → patient profile becomes more convex
○ Upper incisor protrusion
37
Reverse pull headgear
| ● Only effective in children
< 10-11 y/o - before sutures fuse
38
Class III mandibular protrusion treatment options:
● Functional appliance
| ● Chin cup → minimal long term success; rotates mandible down & back, but essentially no change
39
Maxillary constriction treatment
● Rapid or slow palatal expansion (depending on age)
● Lingual arch type in primary & mixed dentition
● RPE ⇒ for near & post-adolescent
40
● Lingual arch type in primary & mixed dentition
| ○ Opens
midpalatal suture in preadolescent
| ○ Can also correct posterior crossbite (moves teeth)
41
Skeletal changes can be made in -----------. Skeletal changes tend to go back a little bit during maintenance period
growing children
42
Is early Class II Tx beneficial ⇒
No
43
● Restraining maxilla (headgear) or growing mandible (fxnal appliance) is
of NO benefit to ultimate growth if done in early mixed dentition over late mixed dentition
44
Class II tx ● With early treatment ⇒
get to same point, but requires 2 phases of treatment
45
```
Is early class III tx beneficial?
● In true maxillary retrusion ⇒
```
max. protraction successful if done before 10 y/o
| ○ ~25% cases still fail; simultaneous expansion questionable
46
Is early transverse treatment beneficial?
● Appears transverse skeletal & dental changes can be made & maintained
○ These changes can affect unerupted teeth
● As arch dimensions change so does available space
47
```
When is early treatment justified:
● For class II ⇒
```
based on benefits of esthetics or trauma reduction
48
```
when is early treatment justified;
● For class III ⇒
```
True maxillary deficiency
and
● Posterior crossbites
49
Normal biologic variation (mild crowding/spacing; class II or III) ⇒
orthodontic treatment
50
Extremes of normal variation (malocclusion of skeletal origin) ⇒
orthodontics & surgery
51
Dysmorphology (often craniofacial anomaly) ⇒
requires craniofacial team
52
Dysmorphology
| ● Etiology →
mostly unknown
53
Dysmorphology
| ○ Also
facial syndromes; postnatal growth disturbances; inherited tendencies; environmental
54
Treatment options for skeletal malocclusion:
● Growth modification
● Camouflage
● Surgical orthodontics ⇒ for severe cares (~5% of malocclusions require surgery)
55
Surgical options for A-P discrepancy (Class II or III)
| ● Le Fort I ⇒
most commonly done maxillary procedure for Class II & III
elongation/shortening
56
● Le Fort I ⇒
| ○ Also treats
facial asymmetry, OSA, max. atrophy
57
● Le Fort I ⇒
| ○ Osteotomy downfracture technique of maxilla →
allows for advancement/retrusion &
58
Surgical options for A-P discrepancy (Class II or III)
| ● BSSO (bilateral sagittal split osteotomy) ⇒
most commonly done mandibular procedure
| ○ To advance or retrude mandible
59
Surgical options for A-P discrepancy (Class II or III)
| ● Genioplasty (inferior border osteotomy
`
○ Increases or decreases prominence of chin (can help either class II or III)
○ Significant esthetic impact
60
Transverse discrepancies:
| ● Maxillary constriction →
most common transverse problem of maxilla
61
Transverse discrepancies:
| ○ SARPE
(surgically assisted rapid palatal expansion)
| ■ Suture fused, so midline osteotomy and then RPE
62
Transverse discrepancies:
| ○ 2 piece Le Forte I
■ Le Forte I split down the middle
| ■ Le Forte I, II, III ⇒ natural weak points of anatomy that surgeon cuts
63
Transverse discrepancies:
| ● Mandibular asymmetry → most common
mand. transverse problem (expansion/constriction rare)
64
Transverse discrepancies:
| ○ Distraction osteogenesis →
can corrects midline asymmetry
65
Transverse discrepancies:
| ○ Mandibular midline osteotomy
uncommon
66
Social-psychological status
● Many adult pts have underlying psychopathologic conditions which need to be managed (ie. depression)
○ Correction will not result in happiness for these pts
● Patients need to be internally motivated for long treatment times
67
● Discrepancies due to deficient growth →
finish growing earlier than excessive growth discrepancies & can be treated earlier
68
Sequence of treatment:
● Pre-surgical orthodontics
● Surgical procedure
● Post-surgical orthodontics
69
● Pre-surgical orthodontics -
```
orthodontic preparation for the planned surgical procedure
○ Eliminate dental compensations (ie. correct upper protrusion/lower retrusion in class III)
○ Dental alignment
○ Facilitates optimal surgery - although it make pt look worse (ie increases negative overjet in CL III), maximizes surgical outcome & pts feel better bc something’s being done
```
70
● Surgical procedure
| ○ Note: one of the least stable surgeries is
setting mandible back; may need elastics post-operatively
71
● Post-surgical orthodontics -
finishing & detailing occlusion
○ Keep post-surgical ortho to minimum
○ Potential for relapse if pt still growing (in case example pt had psychosocial issues, so had to start treatment earlier than ideal)
72
Surgery that stretches muscle/soft tissue →
more unstable
73
Exception to rule →
moving mandible forward stretches soft tissue & moving mandible back relaxes soft tissue
● Soft tissues don’t determine stability
74
Craniofacial Distraction osteogenesis (DO)
● Bone lengthening via gradual expansion of created osteotomy
● DO indicated for more severe situations -
can lengthen 2-3 cm
75
● Use DO over BSSO when you want
> 1 cm bone lengthening
76
Fracture healing phases:
● Inflammation → bone fractured
● Soft callus → soft tissue starts to form around & inside fracture site
● Hard callus → minerals start to form inside/around fx site; bone reunites
● Remodeling → newly formed bone remodeled; bone resorbed to its original condition
77
DO phases of healing
● Latency → phase between osteotomy & activation of distractor
● Distraction → when distractor activated & osteotomy gap widened
● Consolidation → distractor maintained & new bone formed inside gap
○ Gap becomes more radiopaque → indicates new bone formation
78
Distraction force ⇒ main driving force for new bone formation in distraction gap
● During early phase of distraction →
only minimal bone formation around distraction site
| ○ Direction of new bone parallel to distraction force
79
Distraction force
| ● By consolidation phase →
lot of new bone formation
80
○ General pattern of new bone follows
main direction of the distraction force
81
Ossification modes ⇒
intramembranous & endochondral (intermediate cartilage phase)
82
● Distraction has another ossification mode ⇒
transchondroid
○ Intermediate mode between endochondral & intramembranous
● All 3 modes occur at distraction site
83
Periosteum critical for
DO site bone formation
84
● Lateral side of mandible →
osteotomy entry site so greater trauma to periosteum than medial side
85
○ Medial side periosteum more intact →
so formation initially greater, but after weeks of consolidation, lateral side periosteum is restored & new bone formation on lateral side catches up to medial side
86
DO requires good
angiogenesis & blood supply
| ● Vessel formation during distraction; vessel mature during consolidation phase
87
DO site bone formation controlled by multiple factors:
Distraction factors, bone factors, other mechanical factors
88
1. Distraction factors:
| ○ Latency time -
variable
■ Some believe craniofacial bone requires 5-7 days latency, while others believe no latency period required b/c of good blood supply
89
○ Distraction rate -
1 mm/day commonly used
90
○ Consolidation time -
at least double duration of distraction time
91
2. Bone factors:
○ Blood supply & periosteum
| ○ Mesenchymal cells - differentiate into osteoblasts
92
3. Other mechanical factors:
○ Stability of DO site
| ○ Functional loading
93
Advantages of DO
| ● No need for
bone graft (DO can grow bone)
94
Advantages of DO
| ● Significantly larger
bone movement ( > 20mm of mandibular advancement)
95
Advantages of DO
| ● Applicable to
infants & young children
96
Advantages of DO
| ● Can lengthen bone in
multiple dimensions simultaneously thru distraction vector control
97
Advantages of DO
| ● Surgical procedure less invasive than
conventional orthognathic surgery
98
Advantages of DO
| ● Less soft tissue resistance bc of
gradual distraction
99
Advantages of DO
| ● Better long term
stability & less relapse (?)
100
Advantages of DO
| ○ Studies show less relapse from DO at
8 weeks. But at 3 & 6 months → no significant difference (when compared to orthognathic surgery)
101
Advantages of DO
| ○ Maxillary protraction DO study →
no relapse at 2 years; better results with max. protraction, but only 1 study
102
Advantages of DO
| ● Mandibular DO →
less distortion & loading of TMJ than BSSO (?)
103
Disadvantages of DO
● Technique sensitive surgery
● Equipment sensitive surgery
● Less precise control for correction of occlusion
● Pt. compliance required
● Possible secondary surgery to remove devices (if internal distractor being used)
● Increased chance of infection
● Longer treatment time; increased number of office visits & higher cost
104
Indications for craniofacial DO
| ● Severe
micrognathia in infants & children with airway obstruction (ie. Pierre-Robine sequence)
105
Indications for craniofacial DO
| ● =========== with severe ------------ hypoplasia
Hemifacial microsomia
mandibular
106
Indications for craniofacial DO
| ● Mx. deficiency ass. with cleft lip/palate ⇒
DO at Le Fort I level
107
Indications for craniofacial DO
| ● Mx. deficiency ass. with craniofacial dysostosis ⇒
DO at Le Fort III level
108
Indications for craniofacial DO
| ● Mandibular lengthening
> 10 mm
109
Indications for craniofacial DO
| ● Severe sleep apnea due to
Mx/Mn hypoplasia
110
Indications for craniofacial DO
| ● Widening of
constricted mandible
111
Indications for craniofacial DO
| ● Correction of syndromic
craniosynostosis & syndromic midfacial deformities
112
Contraindications of DO
| ● Lack of
adequate bone stock to distract - important; bone needs to be thick & strong enough
● Deficiency/defect can be corrected by traditional orthognathic surgery without bone graft
● Lack of pt compliance (pt needs to activate?)
113
DO vs. orthognathic surgery
● DO can be done in growing children
| ● Long-term stability unclear for both BO & traditional surgery; should only be used for severe cases
114
Camouflage treatment for skeletal problems
● Alternative treatment for non-growing or slow growing pts
● Best for pts with acceptable facial esthetics for minor to moderate skeletal problems
● Adjusts dental relationships with orthodontics &/or extraction
115
Camouflage treatment preference depends on
POV
116
● Traditionally Class II’s were acceptable for
females & Class III for males
117
● Newer data:
| ○ Consumers & oral surgeons believe that both Class II & Class III are more
acceptable in males than females
118
■ Moderate class II equally
acceptable in male & female
119
○ Orthodontists believe that Class II is more acceptable in
females than males
120
Class II camouflage treatment:
| ● Non-extraction →
elastics to retrude upper incisors; reduces overbite
● Extraction in upper or lower jaw
● Facial profile same?
121
Class III camouflage can be difficult
● Retrude lower incisors
122
● Start growth modification at
CVMS 2 or 3
123
○ Stage 3 indicates
peak growth
124
● CVMS cannot tell us when
growth stops; need to do serial cephs
125
● High-pull headgear ⇒
ideal use with high mandibular plane
| ○ Intrudes molars
126
● Cervical pull headgear ⇒
ideal use with low mandibular plane; deep bite
| ○ Extrudes molars (would make open bite worse)
127
Need to decide on camo vs. surgery initially →
bc extraction pattern are opposite
| - Surgical cases occur at different times for maxilla & mandible (wait longer for mandible)
