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ORTHOdontics
PGII/III
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GROWTH MODIFICATION VERSUS ORTHOGNATHIC SURGERY
INCLUDES COMPARISONS BETWEEN POTENTIAL OF THESE MODES OF:
MAXILLOFACIAL ORTHOPEDICS AND DISCUSSION OF
HAZARDS AND LIMITATIONS OF ORTHOGNATHIC SURGERY
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FACULTY:
Joseph Ghafari
, DMD.
Goals: This series of lectures should enable the resident to:
1. Understand how growth modification in the growing child, and orthognathic
surgery in the adult, represent the end components of maxillofacial orthopedics.
2. Recognize the potential and limitations of both modalities.
3. Understand hazards related to orthognathic surgery.
Objectives: The resident should know:
1. The basic concepts underpinning growth modification and orthognathic surgery.
2. The orthognathic process:
athe importance of tooth inclination relative of bone in this process of
normalization among teeth and jaws;
bthe application of this principle in growth modification and orthognathic
surgery;
cthe key role of the orthodontist in this process.
3. The scope of constitutional limitation relating to the fact that the nature of a
dysmorphology is self-limiting, particularly when it is not confined to one facial
feature.
4. That orthognathic surgery, although the favored treatment for many skeleto-dental
dysplasias, may not yield an ideal result because of both constitutional and/or
therapeutic limitations.
5. That the potential of growth modification in a child should not be discarded on the
account of greater bone movement possible with orthognathic surgery at a later
adult age. The level of change also depends on the site of change (mandible, chin,
lips,…). Decisions are best made on where scientific evidence is available.
6. Specific hazards encountered with orthognathic surgery, associated with surgery
proper, or
side effects (periodontal complications, relapse, root resorption).
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COURSE DURATION AND SCOPE: This course is listed within the Maxillofacial Orthopedics series that
also includes Pediatric Orthodontics. The course is scheduled in the Fall of the second year (location of
corresponding examination), but is also attended by third or first year residents because its content lends
itself to evaluation at different times of the educational maturation. It is given at a 2-hour session on a
weekly basis for at least 3 sessions. Preferred precursors to this course are those related to early treatment
and orthognathic surgery.
POLICY ON EXAMINATIONS: At least 2 biannual examinations (progress and final) are given for all
courses, if a course spans the entire year. If classes terminate before the end of a semester, the final
examination is given at the semi-annual examination that is closest to the end of the course, unless the
course director schedules the final examination earlier. During a course, any number of progress tests or
assignments may be given. Their cumulative weight in proportion to the final grade may not exceed 50%.
GROWTH MODIFICATION VERSUS ORTHOGNATHIC SURGERY
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SUMMARY OUTLINE
FOR GM AND OS
1-DIFFERENT
LIMITATIONS OF GM AND ORTHODONTICS WITH OS
POTENTIALS
A-
Constitutional limitations
Therapeutic limitations
AND LIMITATIONS of treatment combining
B2-
HAZARDS
orthodontics and orthognathic surgery
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COURSE OUTLINE
1.
POTENTIAL AND LIMITATIONS OF GROWTH
MODIFICATION AND ORTHOGNATHIC SURGERY
Introduction
Questions are asked and answers are presented that emerge from the evaluation of
research and clinical observations:
1Is the hand of growth in early treatment equal to the hand of the orthognathic
surgeon in the adult. Growth modification may forego the need for surgery under certain
conditions. Timing and duration of treatment are critical.
2What are the limitations of growth modification and treatment combining
orthodontics and orthognathic surgery?
AConstitutional limitations that stem from the nature of the dysmorphology, soft
tissue anatomy and adaptation, and the direction and amount of bone and tooth
movement. The limitations may be related to improper or compromised treatment
planning, as well as side effects of surgery and tooth movement.
Clinical reports, literature review, and pilot research data, help to emphasize the
importance of facial esthetics. Treatment should not be planned based on the skeletal
relationships only. Limitations could be minimized in view of available data, in favor of
expansion rather than constriction of the facial soft tissue mask.
Although orthognathic surgery aims at improving masticatory function and possibly
speech, it offers an opportunity to improve esthetics that should not be missed.
BTherapeutic limitations, which may be related to improper or compromised
treatment planning, direction and amount of tooth movement (dentoalveolar
normalization or decompensation) and bone displacement, as well as side effects of
surgery and tooth movement. The lecture series emphasizes ways to minimize
limitations in view of available scientific data.
1-
POTENTIAL OF GROWTH MODIFICATION AND ORTHOGNATHIC
SURGERY
ABasic Concepts
Similarities in goals regarding amount and direction of bone movement
Growth modification:
Through (orthopedic) forces:
-Change in the absolute size of a jaw
-Redirection of growth
-Differential growth between jaws
Orthognathic surgery:
Through surgery
-Change in the absolute size of a jaw
-Redirection of position
-Differential positioning of jaws
BGrowth modification of the maxilla
Growth modification of the maxilla involves procedures that affect maxillary deficiency
or excess in all planes of space: maxillary size reduction (headgear), expansion (palatal
distraction), or position (retraction or protraction).
-Potential for growth modification depends not only on the patient’s age, but also
constitutional characteristics of the maxillary complex and its relation to the mandible.
-Data analysis from research and clinical sources:
1a longitudinal study of head gear used for 2 years to correct Class II, division 1
malocclusion in prepubertal children (n=36);
2a cross-sectional study of palatal expansion (n=24);
3reports of successful treatment of anterior crossbite and Class III malocclusion
with a facial mask.
-Results indicate that maxillary growth modification limited by
1factors within the maxilla itself (e.g. maturation of sutures; non-concordance of
centers of resistance of maxillary bone and dental components);
2its relation to the mandible (mandibular size dictating maxillary treatment or
causing maxillary retrognathism unless the anterior crossbite is treated early);
3function (e.g. mouth breathing).
CGrowth modification of the mandible
-recognized mostly in the treatment of Class II, division 1 malocclusion.
-severe limitations for
*restriction of mandibular growth in Class III malocclusion;
*mandibular constriction or widening in mandibular transverse problems.
-Controversies on effect of growth modification (functional appliance) regarding
mandibular forward growth stimulation or enhancement. Tested possibilities:
1. mandible surpasses its growth potential- NO conclusive evidence.
2. mandibular growth is accelerated- Difficult to gauge clinically, although demonstrated
in animals.
These hypotheses assume that the individual growth potential can be predicted within
reasonable accuracy.
3. mandible is merely positioned forward and subsequent growth, if sufficient, adapts
(“catches up”) to this position. This hypothesis assumes that
(a) occlusal interdigitation plays an important role in maintaining the mandible in
the
forward position;
(b) the most important effect of a functional appliance is the distal force on the
maxillary
complex. Effect is achieved through forces transferred to maxillary teeth
and bone by the
appliance
DThe orthopedic process
-Natural compensation for skeletal disproportion between jaws with dentoalveolar
inclinations toward a functional occlusion: in Class II malocclusion, maxillary anterior
teeth compensate by retroclining, mandibular incisors by proclination.
1surgery without orthodontics: minimal amount of movement obtained.
2ideally, prior to surgery, orthodontic optimal positioning of teeth over basal bone:
dentoalveolar normalization or decompensation.
3Conceptually, as relates to position of the incisors, growth modification and
orthognathic surgery are different facets of the same coin.
Dentoalveolar normalization, can actually be summed up by getting the teeth out of the
way of the surgeon- or growth- to allow for optimal movement of the bones.
Working guideline in sagittal plane: achieve at the end of presurgical orthodontic process
(or growth process) canine occlusion in Class 1, and optimal inicisal overjet (inclination
of maxillary incisors can limit or require modification of surgical movement –or needed
amount of growth-, particularly when maxillary or mandibular rotation is part of surgery).
2-
LIMITATIONS OF GROWTH MODIFICATION AND ORTHOGNATHIC
SURGERY
In contrast to growth modification, orthognathic surgery can improve the shape of the
chin through genioplasty, but with both modalities, it is difficult to manage the nasolabial
relationship when the nose is tipped upward.
Factors that limit the achievement of optimal esthetics in maxillofacial orthopedics
(growth modifica-tion in growing children, and orthognathic surgery in adults) were
evaluated. Findings suggest that the nature of the dysmorphology is self-limiting from
therapeutic and esthetic perspectives.
2a- Constitution of patient
1Nature of dysmorphology
2Soft tissue evaluation and adaptation
2b- Treatment
1- Treatment planning
2- Direction and amount of bone and tooth movement
3- Duration of treatment or surgery
4- Stability of results and implications
5- Side effects of tooth movement and surgery
A- Limitations of growth modification
If growth modification is started early enough, do we get enough expression of
differential growth to mirror results of orthognathic surgery?
- Research data not available
- Issue of practicality and length of treatment
- WIDE INDIVIDUAL VARIATION
- Incisor inclination: Issue of compensation/decompensation and impact on jaw position
BLimitations of orthognathic surgery
Limitations of orthognathic treatment are also related to the patient’s constitution or to
actual therapeutic limitations.
-*Treatment limitations associated with treatment planning; direction and amount of
bone and tooth movement; duration of surgery; stability of results and implications; and
side effects of surgery and tooth movement.
-*-Critical limitations relate to dentoalveolar normalization: position and inclination of
maxillary incisors can limit or require modification of surgical movement, particularly
when maxillary rotation is planned.
-*-Prediction of outcome is also limiting.
B1- Prediction of soft tissue changes following orthodontics and orthognathic surgery
- wide variation on accuracy of prediction
- limitations related to: variability of conditions in the study of treatment outcome;
variability in surgery (e.g. procedure, extent of movement [over or under treatment],
method of wound closure); variability in anatomy and adaptive potential of soft tissue;
interaction in different planes of space (2D vs. 3D) and between different structures;
factors of tooth movement and growth. However, trends can be described about overall
facial changes and specific features:
B1a- General trends
1Horizontal changes more predictable than vertical changes, which vary
considerably.
-vertical changes smaller in nature, or
-vertical hard tissue changes less predictable and less stable than horizontal
movements.
2Soft tissue response depends on the type of surgical procedure.
B1b- Specific facial features
1Nose: degree of control of nasal changes factor of amount and direction of
surgical movement of the maxilla. Predictability of the response is limited.
2Upper lip:
- vermilion border cannot be increased with orthognathic surgery (may need adjunctive
cosmetic surgery);
- lengthening cannot be achieved with orthognathic surgery (unpredictable success
through cosmetic procedures);
- response to vertical movement maxilla fully predictable (considerable variability).
*In response to down movement, upper lip does not shorten; therefore, the
amount of bony
movement that is needed must be achieved, and should not be
undercorrected.
*Similar rationale applies to maxillary impaction, which also should not be
undercorrected.
- response to forward movement: does not follow in a 1:1 ratio. Reasons: possible
stretching of lip or incision of the lip.
3Lower lip: most variable of soft tissue landmarks in response to orthognathic
movement.
4Chin:
-mandibular advancement: the least variable (generally 1:1 ratio).
-mandibular set back: a submental fold may occur leading to double chin appearance that
would require submental lipectomy.
-genioplasty: remarkable to improve esthetics; should not be overdone. Moving chin
back is least predictable genioplasty because soft tissue displaces at a ratio of less than
0.5 to 1.
Limitations in soft tissue response to movement of underlying hard tissues lead to the
consideration of adjunctive cosmetic procedures (e.g. rhinoplasty, cheiloplasty,
liposection) to improve facial esthetics.
Comparative limitation of treatment between growth modification and surgery
(orthognathic and cosmetic)
Forehead
GM , S
Nose tip
GM > S
B/ST
C/ST
Surgery (P)
Surgery (P)
Length
of upper
lip
GM, S
ST
Surgery??
Thickness of upper lip
GM, S
ST
Surgery (P)
Thickness of lower lip
GM, S
ST
Surgery (P)
Chin (shape of)
GM > S
B/ST
GM- growth modification S- orthognathic surgery
B- bone C- cartilage
ST- soft tissue
2.
1-
Surgery (S, P)
P- plastic surgery
HAZARDS AND LIMITATIONS OF TREATMENT COMBINING
ORTHODONTICS AND ORTHOGNATHIC SURGERY
IMPROPER PLANNING*
A-
Surgery versus orthodontics
- orthodontics without surgery
- surgery without orthodontics
B-
Dentoalveolar compensation
over, under (limited)
C-
Surgery
- Amount of movement (Optimal/Compromised)
(expansion, advancement, setback, impaction, extrusion)
- Asymmetry
D- Growth
additional growth: amount, duration
E-
Soft tissue
thickness and response
2-
SIDE EFFECTS/COMPLICATIONS
A-
Surgery
-surgical technique (healing, complications)
-altered position of mandible
B- Root resorption
C- Periodontal complications
D- Relapse
REFERENCES
PART 1
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problems. In: Contemporary Orthodontics, 3rd ed. Eds, WR Proffit, HW Fields. St. Louis, Mosby.
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treatment. 18th Biennial Growth Seminar, New-Conn Orthodontic Study Group, April 2001.
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the Anatomy of the Chin in a Class II Treatment Population. J Dent Res
PART 2
1. Ghafari J. Root resorption associated with orthognathic surgery: Modified definitions of the resorptive
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mandibular deformities. Am J Orthod Dentofacial Orthop. 2001 Feb;119(2):95-101
4. Wolford LM, Karras SC, Mehra P. Considerations for orthognathic surgery during growth, part 2:
maxillary deformities. Am J Orthod Dentofacial Orthop. 2001;119(2):102-5..
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in "borderline" adults with Class II, division 1 malocclusions. Am J Orthod Dentofacial Orthop. 1993;
104:455-70..
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ADDITIONAL REFERENCES
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Orthod. 1997;67(5):327-36.
2. Arnett GW, Bergman RT. Facial keys to orthodontic diagnosis and treatment planning. Part I. Am J
Orthod Dentofacial Orthop. 1993;103(4):299-312.
3. Arnett GW, Bergman RT. Facial keys to orthodontic diagnosis and treatment planning--Part II. Am J
Orthod Dentofacial Orthop. 1993;103(5):395-411.
4. Arnett GW. A redefinition of bilateral sagittal osteotomy (BSO) advancement relapse. Am J Orthod
Dentofacial Orthop. 1993;104(5):506-15.
5. Arnett GW, Jelic JS, Kim J, Cummings DR, Beress A, Worley CM Jr, Chung B, Bergman R. Soft
tissue cephalometric analysis: diagnosis and treatment planning of dentofacial deformity. Am J Orthod
Dentofacial Orthop. 1999;116(3):239-53.
6. Bailey LJ, Proffit WR, White R Jr. Assessment of patients for orthognathic surgery. Semin Orthod.
1999 (4): 09-22.
7. Bailey LJ, Duong HL, Proffit WR. Surgical Class III treatment: long-term stability and patient
perceptions of
treatment outcome. Int J Adult Orthodon Orthognath Surg. 1998;13(1):35-44.
8. Bailey LT, Proffit WR, White RP Jr. Trends in surgical treatment of Class III skeletal relationships. Int
J Adult Orthodon Orthognath Surg. 1995;10(2):108-18.
9. Buttke TM, Proffit WR. Referring adult patients for orthodontic treatment. J Am Dent Assoc. 1999;
130(1): 73-9.
10. Cassidy DW Jr, Herbosa EG, Rotskoff KS, Johnston LE Jr. A comparison of surgery and orthodontics
in "borderline" adults with Class II, division 1 malocclusions. Am J Orthod Dentofacial Orthop 1993;
104(5): 455-70.
11. Forssell K, Turvey TA, Phillips C, Proffit WR. Superior repositioning of the maxilla combined with
mandibular advancement: mandibular RIF improves stability. Am J Orthod Dentofacial Orthop 1992;
102(4): 342-50.
12. Kantor ML, Phillips CL, Proffit WR. Subtraction radiography to assess reproducibility of patient
positioning in cephalometrics. Am J Orthod Dentofacial Orthop 1993; 104(4): 350-4.
13. Lee DY, Bailey LJ, Proffit WR. Soft tissue changes after superior repositioning of the maxilla with Le
Fort I osteotomy: 5-year follow-up. Int J Adult Orthod Orthognath Surg. 1996; 11: 301-11.
14. Miguel JA, Turvey TA, Phillips C, Proffit WR. Long-term stability of two-jaw surgery for treatment of
mandibular deficiency and vertical maxillary excess. Int J Adult Orthod Orthognath Surg 1995;
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J Orthod 1991; 13(5): 397-403.
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expansion. Int J Adult Orthodon Orthognath Surg 1992; 7(3): 139-46.
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Oral Maxillofac Surg 1989;47(5): 457-63.
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Orthod Dentofacial Orthop 1988; 93(4): 294-302.
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United States: estimates from the NHANES III survey.
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Orthognath Surg 1996; 11(3): 191-204.
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Class II malocclusion in adolescents: effects and indications. Int J Adult Orthod Orthognath Surg
1992;7:209-20.
22. Proffit WR, Bailey LJ, Phillips C, Turvey TA. Long-term stability of surgical open-bite correction by
Le Fort I osteotomy. Angle Orthod 2000; 70(2):112-7.
23. Proffit WR, Miguel JA The duration and sequencing of surgical-orthodontic treatment. Int J Adult
Orthod Orthognath Surg 1995;10(1):35-42.
24. Proffit WR, Phillips C, Douvartzidis N. A comparison of outcomes of orthodontic and surgicalorthodontic treatment of Class II malocclusion in adults. Am J Orthod Dentofacial Orthop 1992 Jun;
101(6):556-65.
25. Rosen HM, Ackerman JL. Porous block hydroxyapatite in orthognathic surgery. Angle Orthod 1991 ;
61(3): 185-91; discussion 192.
26. Sarver DM, Ackerman JL. Orthodontics about face: the re-emergence of the esthetic paradigm. Am J
Orthod Dentofacial Orthop 2000;117(5):575-6.
27. Schubert P, Bailey LJ, White RP Jr, Proffit WR. Long-term cephalometric changes in untreated adults
compared to those treated with orthognathic surgery. Int J Adult Orthod Orthognath Surg
1999;14(2):91-9.
28. Simmons KE, Turvey TA, Phillips C, Proffit WR. Surgical-orthodontic correction of mandibular
deficiency: five-year follow-up. Int J Adult Orthodon Orthognath Surg 1992;7(2):67-79
29. Tulloch JF, Phillips C, Proffit WR. Benefit of early Class II treatment: progress report of a two-phase
randomized clinical trial. Am J Orthod Dentofacial Orthop 1998;113(1):62-72.
30. Van SickelsJE. Distraction osteogenesis versus orthognathic surgery. Am J Orthod Dentofac Orthop.
2000; 118:482-4.
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stability of a bilateral sagittal split osteotomy advancement: wire osteosynthesis versus rigid fixation.
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32. Van Venrooy JR, Proffit WR. Orthodontic care for medically compromised patients: possibilities and
limitations. J Am Dent Assoc 1985 ;111(2):262-6.