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22
3
45
33
Figure 39-1. Facial evaluation: Ideally, as in this figure, the upper lip length (22 mm) is equal to roughly 30% of the lower
third of the face (22 mm + 3 mm + 45 mm).
Figure 39-2. The six developmental stages of cervical vertebral maturation. (From Franchi L, Baccetti T, McNamara JA
Jr: Mandibular growth as related to cervical vertebral maturation and body height, Am J Orthodont Dentofac Orthoped
118(3):335–340, 2000.)
3. Nasolabial angle
4. Ricketts E-line
5. Upper lip length
6. Upper face height-to-total face height ratio
8. What is the Holdaway ratio useful for planning?
The Holdaway ratio is useful in planning a genioplasty. In this instance, the N-B line should be extended
to the inferior border of the mandible and then compare the distances between LI and Pog from this line.
In normal Caucasian males, the comparison is 1:1, while in normal Caucasian females, it is 0.5:1.
9. What is the difference between the goal of nonsurgical orthodontic therapy and
the goal of pre-surgical orthodontic therapy?
The goals of nonsurgical and pre-surgical orthodontic therapy are essentially opposite. While
nonsurgical orthodontics aims to camouflage and mask the patient’s true skeletal deformities by
attempting to achieve the best occlusion, the purpose of pre-surgical orthodontics is to unmask and
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decompensate true skeletal deformities, thereby making the occlusion and the deformity more exaggerated than on initial presentation in a sagittal, transverse, and vertical dimension.
10. What are the limits of movement in orthodontic-only therapy versus orthognathic
surgery?
The limits of orthodontic-only therapy and orthognathic surgery are believed to fall into an envelope
of achievable outcomes as described by Proffit and White. In a growing child, the limits of orthodontic treatment alone are correction of a positive overjet of 8 mm, a negative overjet of 4 mm, and a
transverse discrepancy of 3 mm. In an adult, the achievability of orthodontics are even more limited.
However, orthognathic surgery can correct up to 25 mm positive overjet and 12 mm negative overjet
by surgical intervention in both jaws.
11. What are the different skeletal discrepancies of growth between with the mandible and maxilla?
The major discrepancies between the maxilla and the mandible can occur in one or a combination of
the following dimensions:
• Anterior–posteriordiscrepancy(A–P)
• Verticaldiscrepancy
• Transversediscrepancy
12. What causes maxillary mandibular A–P discrepancy, and how is it manifested?
Anterior–posterior maxillary mandibular discrepancy can be the result of normal growth of the maxilla
with abnormal growth of the mandible, normal growth of the mandible and abnormal growth of the
maxilla, or abnormal growth of both the mandible and maxilla. When the discrepancy is caused by
maxillary deficient growth or by excessive growth of the mandible or both, the resulting deformity is
Class III skeletal deformity and malocclusion. When the discrepancy is caused by normal growth of the
maxilla and deficient growth of the mandible, the resulting deformity is Class II skeletal deformity and
Class II malocclusion.
13. What causes maxillary mandibular transverse discrepancy, and how is it
manifested?
Maxillary mandibular discrepancy is often manifested as a mandibular or maxillary cross-bite,
depending on which jaw is affected. Once again this deformity can be caused by a deficient growth in
one jaw compared to the opposing jaw or can be caused by extraction of one jaw and advancing the
teeth to relieve crowding or in preparation for orthognathic surgery, resulting in a cross-bite.
Cross-bite can be relative or absolute. Relative cross-bite is what can be observed in the
patient’s mouth when the patient has a concomitant anterior posterior discrepancy. An absolute crossbite is when one places the casts of the maxilla and the mandible in Class I canine and still observes
a cross-bite.
14. What is a vertical maxillary mandibular discrepancy?
Just as with other discrepancies, this deformity often occurs in one jaw independently from the
opposite jaw or in combination. Such discrepancies can be manifested as an open bite or deep bite,
depending on in which jaw they occur.
15. Can these discrepancies occur in combination?
Yes. In fact, it is not unusual that the deficient maxillary A–P dimension would be associated with a
vertical or transverse deficient leading to not only Class III skeletal deformity but also to decreased
vertical height of the maxilla (decrease facial height) or a small maxilla in the transverse dimension
leading to a cross-bite.
16. What are the two types of A–P mandibular deficiencies?
1. Low mandibular plane angle type
2. High mandibular plane angle type
Each has distinct morphologic and occlusal presentations, but in both types the mandible is small.
17. What are the features of AP mandibular deficiencies?
The features of the low mandibular plane angle type mandibular deficiency include small mandible,
short facial height, curled-over lower lip, and deep labiomental crease. The angles of the mandible and
the masseters are usually well developed and well defined, and the maxilla may be vertically deficient.
The occlusion shows a curve of Spee, which is generally excessive in both arches. The mandibular
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anterior teeth may occlude with the palate, along with an excessively deep bite. Radiographically, the
ramus height is usually normal, and the angular and linear cephalometric measurements are usually
smaller than normal.
The high mandibular plane angle variety is characterized by normal or excessive face height,
a small and retropositioned chin, flattened labiomental fold, and excessive activity of the mentalis
muscles. The mandibular ramus is short, the condyles are usually small, and the angles of the mandible are obtuse and hypoplastic. The occlusion is characterized by protrusive maxillary teeth, narrow
arch form, constricted mandibular arch, and Class II canine and molar relationships. There may be
an open bite, which is indicative of conditions such as rheumatoid arthritis, temporomandibular joint
(TMJ) ankylosis, and condylar resorption. If AP mandibular deficiency of the high mandibular plane
angle type exists along with vertical maxillary excess, all the features of vertical maxillary excess are
present, and the features of mandibular deficiency are exaggerated.
18. How is mandibular deficiency treated?
Treatment of isolated mandibular deficiency usually involves mandibular advancement. Bilateral
sagittal split osteotomy (BSSO) with rigid fixation is the most frequently performed procedure to
accomplish this advancement. Inverted-L osteotomy with rigid fixation and bone grafting is recommended for advancement >1 cm. In general, stability of mandibular advancement is better with
smaller amounts of advancements than with large ones. More recently, distraction osteogenesis
has become a more popular procedure for treatment of mandibular deficiency and hypoplasia than
inverted-L osteotomy with bone graft. Augmentation genioplasty procedures using an alloplastic
or osteoplastic technique with and without the BSSO technique occasionally are used to disguise
significant mandibular deficiency. Also, mandibular subapical osteotomy may help in leveling the
mandibular arch.
19. What are the features of mandibular prognathism?
Although isolated mandibular prognathism is a rare condition, mandibular prognathism often is
associated with maxillary deficiency. When the two conditions are present together, the appearance of
mandibular prognathism is exaggerated. Overclosure of the vertical dimension and centric relationcentric occlusion slides also may coexist and exaggerate such appearance. The chin and lower lip in
patients with these conditions are forward relative to the upper lip, often making them the dominant
facial feature. The mandibular body and mandibular angle are well defined, often with an obtuse
angle. The occlusion is Class III, and often the skeletal discrepancy is greater than the occlusal discrepancy because of the dental compensations. Such compensation is manifested as flared maxillary
anterior teeth and upright mandibular anterior teeth.
20. How is mandibular prognathism treated?
Sagittal split osteotomy with rigid fixation is the procedure of choice for correction of mandibular
prognathism. Transoral vertical ramus osteotomy is advocated by some, especially for large posterior
movement and when there is a need for an asymmetric setback. However, problems with control of
the proximal segment and adverse postsurgical occlusal changes have been reported with this procedure. Surgery should be undertaken only after dental compensations are eliminated with pre-surgical
orthodontics and, preferably, after mandibular growth is completed.
21. What are the three modifications of BSSO procedure?
1. Hunsuck modification: Extend the cut posteriorly and slightly past the lingula into the retrolingular
fossa. This creates an easier procedure and causes less soft tissue trauma.
2. Dalpont modification: Make the lateral osteotomy more anterior to the level of the second molar,
which increases surface area of contact.
3. Epker modification: Dissection is carried out, only as needed, avoiding excessive stripping of the
masseter and medial pterygoid muscles. This causes less swelling and postoperative discomfort as
well as preservation of blood supply.
22. What are the possible complications of a BSSO?
Complications of BSSO are classified as either intraoperative or postoperative. The most common
complications of mandibular procedures in general, and BSSO in particular, include unfavorable
osteotomy splits (fracture of the proximal or distal segments), nerve injury, vascular injury and
bleeding, and proximal segment malpositions. Mandibular dysfunction (including TMJ dysfunction
symptoms), relapse, wound infection, and wound dehiscence are some of the postoperative possible
complications.
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23. What is the incidence of unfavorable split osteotomy during BSSO? How is this
complication treated?
An unfavorable split between the proximal and distal segments occurs in 3.1% to 20% of cases. The use
of heavy osteotome and twisting technique is believed to be the main cause. An unfavorable split should
be treated by completing the osteotomy and using plates and screws to fix the fractured segments.
24. What is the incidence of neurosensory deficits following BSSO?
Neurosensory deficits of the inferior alveolar nerve following BSSO are one of the most significant
concerns with this procedure. Complications occur in 20% to 85% of surgeries. However, the incidence is only 9% at 1 year after surgery. This complication is more common in patients older than
age 40 and in patients who undergo simultaneous genioplasty.
25. What is the most likely source of profuse bleeding during internal vertical ramus
osteotomy (IVRO)?
Masseteric artery: This passes through the sigmoid notch and is approximately 25 mm from the
anterior border of the ramus and 8 mm above the sigmoid notch.
Inferior alveolar artery: The mandibular foramen is rarely less than 7 mm away from the
posterior border.
Internal maxillary artery: It is found medial to the mandible at the level of the condylar neck.
Retromandibular vein: This is due to excessive retromandibular dissection or accidental dam-
age to this vessel.
26. In which mandibular ramus osteotomy is inferior alveolar nerve (IAN) damage
most common?
IAN damage is most common in BSSO, noted in 33% of cases after 20 months of follow-up. On the
otherhand,IANinjuryduetoVROisfarlesscommon,withameanof9%after21monthsoffollowup.Duringinverted-Losteotomy,riskofIANisuncommonandseenfarlessthaninBSSOandVRO,as
the osteotomies are performed posterior to the lingula. However, a transcutaneous approach during
inverted-L osteotomy may lead to damage to the marginal mandibular nerve.
27. How can tooth damage be prevented in subapical osteotomy?
The horizontal osteotomy should be positioned greater than 5 mm below the root apices to avoid
inadvertent tooth injury or devitalization.
28. When is genioplasty indicated?
The genioplasty procedure is used to correct functional as well as cosmetic deformities.
29. What is a consequence of genioplasty due to incorrect suturing?
During genioplasty, closure of the incision must include reconstruction of the mentalis muscles with
30. What are the different types of genioplasty procedures?
• Horizontalosteotomywithadvancement:forcorrectionofpurehorizontalmicrogenia
• Double-slidinghorizontalosteotomy:forthecorrectionofsignicantmicrogenia
• Horizontalosteotomywithanteriorposteriorreduction:forcorrectionofanisolatedchinexcess
• Verticalreductiongenioplastybyahorizontalresection:forcorrectionofanisolatedverticalexcess
• Obliqueosteotomyandadvancementcaudally,orcaudallyandinferiorly,withplacementofinter-
• Alloplasticaugmentation
31. How can the angles of the osteotomy influence the movement of the distal
The more parallel the osteotomy line with the occlusal plane and the mandibular plane, the more pure
Lower facial height deformities, including excessive length, can contribute to functional problems
such as lip incompetence and open mouth posturing. Mental soft tissue strain to compensate for
these deficiencies can result in thinning of mandibular alveolar bone. Many cosmetic and functional
deformities such as retrognathia, microgenia, asymmetry, and excessive or shallow labiomental fold
can be corrected with the osseous genioplasty.
a slowly resorbing suture. The result of incomplete approximation or fast resorbing sutures may be
chin ptosis, or a “Witch’s Deformity,” drooping of the chin below the jawline.
position graft: for correction of pure vertical deficiency or a combination of vertical and horizontal
deficiency
segment?
the AP movement. If vertical shortening is desired, the angle of the osteotomy should become more
acute compared with the mandibular plane.
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32. What are the possible complications of the alloplastic chin augmentation?
• Infection
• Boneresorptionbeneaththeimplant
• Extrusionandrejection
• Lesspredictableandstable
• Dehiscence
• Lessversatile
• Malposition
33. What are the possible complications of osseous genioplasty?
• Wounddehiscenceandinfection
• Softtissuechinptosis
• Hematoma
• Rootexposures
• Toothdevitalization
• Asymmetry
• Neurosensoryloss
• Irregularitiesandstep-typedeformities
34. What are the clinical features of vertical maxillary excess (VME)?
VMEischaracterizedbyexcessivetoothdisplayatliprepose,excessivegingivalexposureonsmiling,
and lip incompetency. An open bite is almost always present, especially when there are steps in
the maxillary occlusal plane. The face height is always long, and the chin is rotated downward and
posteriorly. This condition is exaggerated by the presence of a short upper lip or maxillary protrusion.
VMEcanbeseenwithClassI,II,orIIIocclusions.
35. How is VME treated?
VMEcanbetreatedwithorthodonticinterventionearlyinlife(ages8to12)withhigh-pullheadgear
or open bite Bionater to control vertical growth of the maxilla. If successful, such treatment may
resolve the skeletal abnormalities, and ultimately the soft tissues and other facial structures grow
accordingly. However, when an adult presents with this condition, it usually is treated with Le Fort I
osteotomy and superior repositioning of the maxilla.
36. Are there any special factors that should be considered when treating VME?
Yes. Because the vertical growth of the maxilla is the last vector to cease, the excessive vertical devel-
opment may continue growing later than expected. If significant vertical growth occurs, postsurgical
relapse can result. Accordingly, as with most deformities characterized by excessive growth, delaying
surgeryuntilgrowthhasslowedorcompletedisrecommended.However,ifVMEissevere,early
surgery may be justified on the basis of psychosocial benefits.
37. What are the causes of posterior VME?
• Whenopposingposteriormandibularteethhavebeenextracted,passiveeruptionofthemaxillary
teeth results.
• PosteriorVMEalsomaybecausedbyexcessivemaxillaryverticalgrowth,whichisusuallyassoci-
ated with anterior open bite.
38. What are the clinical and radiographic features of posterior VME?
A distinct step in the maxillary occlusal plane is usually present. When posterior maxillary vertical
excess occurs due to passive eruption of teeth, the condition is usually associated with inadequate
inter-arch space, which poses a serious prosthetic challenge. Facial change is not apparent because
thepassiveeruptionceaseswhentheteethcontactthemandibularridge.WhenposteriorVMEoccurs
in the dentate state, there is an increased facial height with lip incompetency secondary to downward
and backward rotation of the mandible. The maxillary incisor-to-lip relationship may be normal, but
during animation excessive gingiva shows in the posterior region.
Radiographic features of both conditions include excessive distance from the palatal plane to the
first molar cusp. In the partially edentulous patient, excessive pneumatization of the maxillary sinus
may be seen.
39. How is posterior VME treated?
TreatmentofposteriorVMEinvolvesaninterdentalosteotomyandsuperiorpositioningoftheposterior
segment. If inadequate space exists between the teeth, orthodontic movement or extraction of a tooth
is necessary to avoid damage to adjacent teeth.
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In the partially edentulous patient, the anterior occlusion should not change if isolated posterior
maxillary osteotomy is performed. In the dentate state, superior repositioning of the posterior maxilla
results in closure of the open bite, shortening of the face height, improved lip competency, improved
mandibular rotation, and forward projection of the chin.
40. What are the clinical and cephalometric features of maxillary vertical deficiency?
• Maxillaryverticaldeciencyisoftenpresentwithotherskeletalabnormalities,suchasAPortrans-
verse maxillary deficiency or mandibular prognathism.
• Thelowerfaceheightisalwaysreduced,andthefreewayspaceisexcessive.
• Often,themaxillaryincisorsarecompletelycoveredbytheupperlipatrest,withonlyaportionof
the crowns exposed when smiling, and a proper-sized mandible will appear prognathic because of
the over-closed position.
• TheocclusionistypicallyClassIIIwithdifferencesbetweencentricrelation-centricocclusion.
• Cephalometrically,thepalatalplanetorstmolardistanceisalwaysreduced.
41. How is vertical maxillary deficiency treated?
Treatment of vertical maxillary deficiency usually involves Le Fort I osteotomy with down-grafting,
often in combination with mandibular osteotomy.
42. What are the features of maxillary AP deficiency? How is it treated?
AP deficiency of the maxilla is typically characterized by paranasal deficiencies, deficiency of the infra-
orbital region, and lack of zygomatic prominence. The upper lip behind the lower lip is the soft tissue
characteristic. The occlusion is Class III with compensatory flaring of the maxillary anterior incisors in
the true condition and is overly retracted if premolars have been removed previously to compensate
orthodontically for mandibular deficiency. Cephalometrically, the maxillary unit length measurements
may confirm the diagnosis. Treatment of maxillary AP deficiency usually consists of Le Fort I advancement with or without bone grafts, depending on the extent of advancement.
43. What are the clinical characteristics of transverse maxillary deficiency? What is
the best radiographic method of diagnosis of this deficiency?
The clinical indicators of transverse maxillary deficiency include unilateral or bilateral palatal cross-
bite; crowded, rotated, and palatally or buccally displaced teeth; a narrow tapering maxillary arch
form; and a narrow, high palatal vault. The soft tissue features are limited to a degree of paranasal
hallowing, narrow nasal base, deepened nasolabial folds, and zygomatic hypoplasia. When sagittal
and vertical dysplasia exist concomitantly with a maxillary transverse deficiency, they often mask the
transverse deficiency. Patients who present with cross-bite should be examined closely to determine
whether such finding represents a displacement of the teeth relative to the basal bone or a true skeletal bite due to a wide mandible or narrow maxilla. Generally, if a cross-bite involves more than one or
two teeth, the cross-bite is probably skeletal.
For diagnosis and determination of transverse maxillary deficiency, PA cephalogram has been
used for identification and evaluation of transverse skeletal discrepancy. More recently, CBCT can
provide more accurate assessment and treatment planning for this deformity.
44. What are the treatment methods of transverse maxillary deficiency?
The method of correction used depends on several factors, including whether the deficiency is skeletal or
dental, or both; the patient’s skeletal growth; the magnitude of the transverse discrepancy; and the periodontal status of the dentition. The treatment commonly used is either orthopedic maxillary expansion
or surgically assisted maxillary expansion (SME). SME is indicated in non-growing patients (skeletal age
is 15 years or older) and in failed orthodontic/orthopedic expansion and when the maxillary transverse
deficiency is >5 mm, when there is a significant transverse maxillary deficiency associated with a narrow
maxilla and wide mandible. It is also indicated if there is extremely thin, delicate gingival tissue, in the
presence of significant buccal gingival recession in the maxillary canine–premolar region.
Sometimes the transverse discrepancy is the result of a mandibular advancement, especially
after extraction of the mandibular bicuspid, with a normal maxillary transverse dimension; a midline
mandibular osteotomy combined with BSSO and narrowing of the mandible posteriorly can be used to
correct such cross-bite.
45. What are the components of the technique of SME?
Although several techniques have been described to accomplish the expansion of the transversely
deficient maxilla, most authors agree on the following steps of the technique:
1. Bilateral osteotomy of the maxilla from the piriform rim to the pterygomaxillary fission
2. Release of the nasal septum
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3. Midline palatal osteotomy
4. Osteotomy of lateral nasal walls
5. Bilateral osteotomy of pterygoid plates from the maxillary tuberosity
6. Activation of the maxillary appliance to a total widening of l.0 to 1.5 mm to assure mobility of both
sides of the maxilla
7. Soft tissue closure in a similar fashion to that of Le Fort I osteotomy, preferably using alar cinch
andV-Yclosure
46. What are the indications of Le Fort I segmental osteotomy over Le Fort I single-
piece osteotomy?
Le Fort I segmental osteotomy should be utilized in cases of maxillary deformities that include multiple
planes of occlusion or steps such as seen in apertognathia that require segmentation to correct. However, use segmental Le Fort I osteotomy to correct transverse maxillary deficiency as seen commonly
inClassIIImalocclusionandVME,butonlyincasesthatrequirenotmorethan5to7mminexpansion. It is important to be selective about electing Le Fort I segmental osteotomies as it has a higher
risk of necrosis of a dento-osseous segment, periodontal deformities (caused by large steps and gaps
in the alveolus), and dental injury.
47. What are the possible complications of a Le Fort I osteotomy?
Intraoperative Complications
• Unfavorableosteotomy
• Bleeding
• Impropermaxillaryrepositioning
• Inabilitytostabilizethemaxilla
• Falseaneurysms
Postoperative Complications
• Relapse
• Ophthalmicinjury(rare)
• Bleeding
• Condylarmalpositioning(rare)
• Neurologicdysfunction
• Avascularnecrosisofsegment(rare)
• Unfavorablefacialaesthetics
• Infectionlessthan1%ofcases
• Non-union:Fewreportsareavailableandthetrueoccurrenceislikelyunderstated
48. Is it necessary to preserve the greater palatine vessels during Le Fort I
osteotomy?
No. Studies have found no change in outcome even when both descending palatine vessels are
ligated. This finding is also supported by biologic investigations that determine the blood supply to
the maxilla, after the osteotomy, to be provided by the ascending pharyngeal artery, ascending palatal
artery, and the adjacent soft tissue pedicles.
49. What is the incidence of neurosensory dysfunction after Le Fort I osteotomy?
InjurytocranialnerveV2isthemostcommoninjury,with25%ofpatientsexperiencingreduced
nociceptiveresponsetopinpricks.InjuryalsohasbeenreportedtocranialnerveIVandtheparasym-
pathetic fibers of the lacrimal gland.
50. If injured, which artery may cause brisk and serious bleeding during Le Fort I
osteotomy?
The descending palatine artery, which passes through the palatine bone to enter the palatal soft tis-
sue at the medial maxillary sinus wall in the posterior hard palate, must be handled carefully to avoid
severance. Delayed and serious bleeding can be encountered in the postoperative period as late as
several weeks following the procedure. The patient can present with profuse epistaxis >2 weeks after
the Le Fort 1 as breakdown of a clot or necrosis of the injured arterial vessels can occur.
51. What is the most likely source of profuse bleeding following Le Fort I incision but
before bony osteotomy?
The posterior superior alveolar artery, which is located at the posterolateral surface of the maxilla, is
often encountered during reflection of the periosteum off the bone before making the bony cut. If these
vessels are lacerated, they bleed profusely. This bleeding can easily be controlled with pressure packing.
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52. Is it necessary to preserve the greater palatine vessels during Le Fort I
osteotomy?
No. Studies have found no change in outcome even when both descending palatine vessels are
ligated. This finding is also supported by biologic investigations that determine the blood supply to
the maxilla, after the osteotomy, to be provided by the ascending pharyngeal artery, ascending palatal
artery, and the adjacent soft tissue pedicles.
53. When is it advised to perform a surgically assisted rapid palatal expansion
(SARPE) instead of segmental Le Fort I osteotomy?
SARPE is indicated in cases that contain in excess of 5 mm of transverse maxillary deficiency at the
first molar; in isolated maxillary transverse deficiencies; and in skeletally mature or failed orthodontic
expansion. However, complications of SARPE may include periodontal defects if the midline osteotomy
does not enter the mid-palatal suture line or when the rate of expansion is greater than biological limits.
54. Which orthognathic procedure has the highest degree of relapse?
According to Proffit et al. transverse expansion of the maxilla is the most unstable orthognathic proce-
dure. The greatest relapse is seen in the second molar region, with an average of 50% loss of surgical
expansion. After 1 year, inferior maxillary positioning and mandibular setbacks were also found to be
less predictable than in other surgical techniques.
55. What is idiopathic condylar resorption?
Idiopathic condylar resorption of the mandibular condyle is a progressive dissolution of the condylar
head without a history of apparent direct cause. The condition is seen mostly after orthognathic surgery, although it has been reported in patients who are undergoing or who have finished orthodontic
treatment.
56. What are the causes of idiopathic condylar resorption?
Several clinical and radiographic risk factors have been reported in the literature, but the exact causes
and pathogenesis of the condition remain unclear.
Patient-Related Risk Factors
• Age(young)
• Highmandibularplaneangle
• Gender(female)
• Shortposteriorheight
• PreoperativeTMJdysfunctionsymptoms
• Smallposterior-to-anteriorfacialheightratio
• Mandibularhypoplasia
Surgery-Related Risk Factors
• Counterclockwiserotationoftheproximalanddistalsegments
• Surgicallyinducedposteriorcondylardisplacementinpatientswithextremelyhighmandibular
plane angle
• Typeofxation(wireosteosynthesisandintermaxillaryxation;controversial)
• Directionanddegreeofmandibularmovement(severemagnitudemandibularadvancement;
controversial)
• Condylardisplacementafterorthognathicsurgery(controversial)
57. What are the clinical manifestations of condylar resorption?
The clinical signs of occlusal relapse after orthognathic surgery or orthodontic treatment develop
before the radiographic sign of condylar resorption. The resorptive process can occur unilaterally
or bilaterally and usually starts within the first year after treatment. Clinically, idiopathic condylar
resorption is manifested by progressive development of anterior open bite and posterior rotation of the
mandible with Class II canine and molar relation. The patient often begins to appear retrognathic and
occludes mostly on the posterior teeth. The patient may have pain or changes in range of motion. In
some patients, the clinical presentation of condylar resorption is similar to that of rheumatoid arthritis.
If pain is present, it usually is mild in proportion to the degree of radiographic changes in the joint.
The radiographic features of condylar resorption include generalized resorption of the condylar
head, often bilaterally, with anterior rotation of the condylar stump in the glenoid fossa. The resorption
process often continues regardless of treatment until the entire condylar head resorbs. Bone scintigraphy often shows an increased uptake throughout the resorptive process that may not be interrupted
by a period of decrease or cessation of uptake.
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58. What are the treatment options of condylar resorption?
As with other progressive condylar changes, a critical step in treatment planning for condylar resorption is
to determine whether the condition is still progressing or has ceased. A history of recent occlusal changes
and scintigraphy is important to determine the stage of the condition. Most authors agree on delaying surgical intervention, especially orthognathic surgery, until the resorptive activity has stopped. During such
activity, nonsurgical measures, such as nonsteroidal antiinflammatory drugs (NSAIDs) and splint therapy
are recommended. Once the resorptive process ceases, orthognathic surgery or condylar replacement
with alloplastic or costochondral graft (the two most common surgical modalities) is performed. Recent
reports show higher stability after costochondral graft than with orthognathic surgery alone.
BiBliography
Abubaker A, Strauss R: Genioplasty: a case for advancement osteotomy, J Oral Maxillofac Surg 58:783–787, 2000.
Apinhasmit W, Chompoopong S, Methathrathip D, et al.: Clinical anatomy of the posterior maxilla pertaining to Le Fort I
osteotomy in Thais, Clin Anat 18:323–329, 2005.
Arnett GW, Tamborello JA: Progressive class II development: female idiopathic condylar resorption, Oral Maxillofac Surg
Clin North Am 2:699, 1990.
Bailey L, White R, Proffit W, et al.: Segmental Le Fort I osteotomy for management of transverse maxillary deficiency, J Oral
Maxillofac Surg 55:728–731, 1997.
Bell W: Modern practice in orthognathic and reconstructive surgery, Philadelphia, 1992, Saunders.
Bell W, You Z, Finn R, Fields R, et al.: Wound healing after multisegmental Le Fort I osteotomy and transection of the
descending palatine vessels, J Oral Maxillofac Surg 53:1425–1433, 1995.
Betts N, Dowd K: Soft tissue changes associated with orthognathic surgery, Atlas Oral Maxillofac Surg Clin North Am
8:13–38, 2000.
Boye T, Doyle P, Mckeown F, et al.: Total subapical mandibular osteotomy to correct class 2 division 1 dento-facial defor-
mity, J Cranio-Maxillofac Surg 40:238–242, 2012.
Cheung L, Chua H, et al.: A meta-analysis of cleft maxillary osteotomy and distraction osteogenesis, Int J Oral Maxillofac
Surg 35:14–24, 2006.
Cheung L, Fung S, Li T, et al.: Posterior maxillary anatomy: implications for Le Fort I osteotomy, Int J Oral Maxillofac Surg
27:346–351, 1998.
Chua H, Hägg M, Cheung L, et al.: Cleft maxillary distraction versus orthognathic surgery—which one is more stable in 5
years? Oral Surg Med Oral Pathol Oral Radiol Endod 109:803–814, 2010.
Crawford FG, Stoelinga PJ, Blijchop PA, et al.: Stability after reoperation for progressive condylar resorption after orthogna-
thic surgery: report of 7 cases, J Oral Maxillofac Surg 52:460–466, 1994.
Epker BN, Wolford LM: Surgical correction of dentofacial deformities, St Louis, 1980, Mosby.
Franchi L, Baccetti T, McNamara J, et al.: Mandibular growth as related to cervical vertebral maturation and body height,
Am J Orthodont Dentofac Orthop 118:335–340, 2000.
Fujimura K, Segami N, Kobayashi S, et al.: Anatomical study of the complications of intraoral vertico-sagittal ramus oste-
otomy, J Oral Maxillofac Surg 64:384–389, 2006.
Greer Walker D: Facial development. Lecture presented at Arris and Gale lecture in England, Stoke Mandeville Hospital;
Middlesex Hospital; Royal Dental Hospital. In Grubb J, Evans C, et al.: Orthodontic management of dentofacial skeletal
deformities. Clinics in plastic surgery , March 28, pp 403–415, 1957.
Guyuron B: Genioplasty, Washington, DC, 1993, Library of Congress.
Hoppenreijs TJ, Freihfer M, Stoelinga PJ, et al.: Condylar remodeling and resorption after Le Fort I and bimaxillary osteoto-
mies in patients with anterior open bite. A clinical and radiographic study, Int J Oral Maxillofac Surg 27:81–91, 1998.
Huang YL, Pogrel MA, Kaban LB: Diagnosis and management of condylar resorption, J Oral Maxillofac Surg 55:114–119, 1997.
Hwang SJ, Haers PE, Zimmermann A, et al.: Surgical risk factors for condylar resorption after orthognathic surgery, Oral
Surg Oral Med Oral Pathol Oral Radiol Endod 89:542–552, 2000.
Jegal J, Kang S, Kim J, Sun H: The utility of a three-dimensional approach with T-shaped osteotomy in osseous genio-
plasty, Arch Plast Surg 40:433–439, 2013.
Lanigan D, Hey J, West R, et al.: Major vascular complications of orthognathic surgery: false aneurysms and arteriovenous
fistulas following orthognathic surgery, J Oral Maxillofac Surg 49:571–577, 1991.
Mori Y, Shimizu H, Minami K, Kwon T, Mano T: Development of a simulation system in mandibular orthognathic surgery
based on integrated three-dimensional data, Oral Maxillofac Surg 15:131–138, 2011.
O’Ryan F: Complications of orthognathic surgery, Oral Maxillofac Surg Clin North Am 2:593–613, 1990.
Pereira F, Yaedú R, Sant’ana A, Sant’ana E, et al.: Maxillary aseptic necrosis after Le Fort I osteotomy: a case report and
literature review, J Oral Maxillofac Surg 68:1402–1407, 2010.
Proffit W, Turvey T, Phillips C, et al.: The hierarchy of stability and predictability in orthognathic surgery with rigid fixation:
an update and extension, Head Face Med 1–11, 2007.
Proffit W, Turvey TA, Phillips C: Orthognathic surgery: a hierarchy of stability, Int J Adult Orthodont Orthognath Surg
11:191–204, 1996.
Reyneke J: Essentials of orthognathic surgery, Chicago, 2003, Quintessence Publishers.
Steel B, Cope M, et al.: Unusual and rare complications of orthognathic surgery: a literature review, J Oral Maxillofac Surg
1678–1691, 2012.
Tucker M, et al.: Orthognathic surgery versus orthodontic camouflage in the treatment of mandibular deficiency, J Oral
Maxillofac Surg 53:572–578, 1995.
Turvey TA: Maxillary expansion: a surgical technique based on surgical-orthodontic treatment objectives and anatomical
considerations, J Maxillofac Surg 13:51–58, 1985.
DISTRACTION OSTEOGENESIS
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Din Lam
1. What is distraction osteogenesis?
Distraction osteogenesis is bone formation in the gap between gradually distracted bone ends on each
side of a corticotomy. The technique requires the creation of an osteotomy followed by the application
of a medical distractor to separate the bone segments at a controlled rate. The process is based on
the principle that tension stimulates histogenesis and does not require the use of a bone graft or rigid
fixation of the bone segments.
2. What are the four phases of distraction osteogenesis?
Phase I: Osteotomy—creation of bony segments.
Phase II: Latency—allow soft callus to form. Length of latency depends on patient age. Most protocols
ask for 3 to 7 days of latency period, unless the patient is a neonate; in such cases, distraction
can start 1 day after osteotomy.
Phase III: Distraction—0.5 mm twice a day is the most common protocol for distraction.
Phase IV: Consolidation—allows for hard callus formation. Most protocols recommend a
consolidation phase of at least 6 to 8 weeks.
3. What are the advantages of distraction osteogenesis?
• Reduced risk of infection seen in nonvascularized bone grafts
• Eliminated need for donor site harvesting
• More predictable bone survival
• Provides both soft and hard tissue expansion simultaneously
4. What are the four zones of tissue generation in the intercalary gap?
Zone 1: Fibrous central zone
Zone 2: Transition zone, features osteoid formation along the collagen bundles
Zone 3: Remodeling zone, osteoclasts work to remodel the newly formed bone
Zone 4: Zone of mature bone
5. What are the three types of distraction?
1. Unifocal distraction: A single osteotomy is made and distraction forces are applied by a device
attached by screws on either side of the osteotomy.
2. Bifocal distraction: This is one osteotomy with pins on either side of osteotomy and defect and with
a single spanning device encompassing the transport system.
3. Trifocal distraction: Osteotomy is made on both ends of the bony defect. Each end is distracted
until the two distracted segments join each other in the center of the intercalary gap.
6. How are distraction devices categorized?
• Internal device versus external device versus semi-buried
• Unilateral vector versus curvilinear versus multi-vector
7. What are the vectors of distraction?
The vector of distraction is based on the long axis of the distraction device. In the mandible, there
are three types of distraction vectors: horizontal, oblique, and vertical. A horizontal vector is 0 degree
to 30 degrees, an oblique vector is 30 degrees to 45 degrees, and a vertical vector is greater than
45 degrees. The trajectory of the distracted mandible can be predicted based on the vector of distraction. The horizontal vector is preferred in the patient with mandibular body deficiency. The vertical
vector is used in the condyle reconstruction.
8. How is new bone formed during distraction osteogenesis?
Intramembranous ossification.
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CHAPTER 40
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