96 Wolford, Karras, and Mehra American Journal of Orthodontics and Dentofacial Orthopedics February 2001patients is the displaced articular disk. Significant prob- [MRI], or nuclear scintigraphy) are indicated in cer-lems can occur when orthognathic surgery is performed tain cases, especially for identification of TMJ pathol-in the presence of untreated disk displacement.7,8 ogy. Hand-wrist films may be useful in determiningBefore surgery, 36% of patients had some pain or dis- the growth potential in some patients but are of littlecomfort, but 2 years after mandibular advancement, benefit in skeletal Class III patients with condylar88% of the patients had pain with increased intensity. hyperplasia. Serial dental models help in monitoringAfter surgery, condylar resorption occurred in 30% of occlusal and dental changes.the patients, which resulted in redevelopment of a jawdeformity and malocclusion.8 Other TMJ pathologic MANDIBULAR DEFORMITIESconditions that may affect treatment outcomes include Mandibular hypoplasiacondylar hyperplasia, condylar hypoplasia, idiopathic Mandibular hypoplasia is defined as retruded man-condylar resorption, osteochondroma, reactive arthritis, dibular position resulting in a Class II skeletal relation-rheumatoid arthritis, psoriatic arthritis, systemic lupus ship with either a normal or a deficient mandibularerythematosus, scleroderma, and ankylosing spondyli- growth rate.tis. TMJ pathology must be assessed and properly man- Normal growth rate. In patients with normalaged to provide healthy, stable TMJs for a sound foun- mandibular growth, the mandible grows from adation and the achievement of predictable results. retruded position relative to the normally positioned The tongue is an important factor in jaw growth and maxilla, or it may be smaller. With normal rates ofdevelopment. Microglossia can cause underdevelop- maxillary and mandibular growth, the same Class IIment of the jaws with lingual collapse of the dentoalve- skeletal and occlusal relationship is maintainedolar structures. Macroglossia can result in overdevelop- throughout growth.11 This deformity can be correctedment of the jaws, especially the dentoalveolus. The surgically during growth, with predictably stableetiology of macroglossia may be congenital (eg, mus- results, by using the mandibular ramus osteotomiescular hypertrophy, lymphangioma, or glandular hyper- discussed below. With healthy TMJs and proper use ofplasia) or acquired (eg, cyst, tumor, acromegaly, or these techniques, the rate of growth is essentially unal-amyloidosis). The most common cause of macroglossia tered by surgery, and harmonious postoperative maxil-is muscular hypertrophy. lary and mandibular growth can be expected with The tongue usually reaches its approximate adult maintenance of the surgical result.12-14size when a child reaches the age of 8 years.9 An eval- Deficient growth rate. Patients experiencing defi-uation of the tongue should include clinical, radi- cient mandibular growth are initially seen with pro-ographic, and functional assessments relative to inter- gressively worsening mandibular retrusion and Class IIference with speech, mastication, airway, and treatment malocclusion, as normal maxillary growth outpaces thestability. Surgical reduction of the tongue can improve deficient mandibular growth. If the deformity is cor-the stability and predictability of surgical outcomes in rected surgically during growth, a Class II skeletal andcases of absolute macroglossia. Wolford et al10 previ- occlusal relationship can be expected to recur, as theously described the diagnosis of macroglossia and the maxilla continues to grow normally and the mandibleindications for reduction glossectomy. maintains its deficient growth rate.15 However, surgery Determination of growth rate and vector can be during growth may be indicated in cases of severechallenging. Because the jaws grow in all 3 dimen- deformities that adversely affect function (eg, malnu-sions, growth disturbances can also occur in more than trition resulting from masticatory dysfunction, airway1 dimension. A good understanding of facial growth compromise, or speech disorders) or psychosocialtendencies of the specific anatomical facial types (eg, development. Under these circumstances, surgery dur-brachycephalic, normocephalic, or dolicocephalic) ing growth may improve the quality of life, but thegives the clinician important information about subse- patient and parents must be made aware that additionalquent growth. Evaluation of the patient’s medical and surgery will probably be necessary. Patients with defi-family history, as well as serial clinical and radi- cient mandibular growth may have an associated TMJographic examinations, are helpful to identify growth pathology that requires surgical correction to achieve aimbalances in jaw structures. Comparison of serial lat- stable outcome. Any of the ramus osteotomies dis-eral and anteroposterior cephalograms, and cephalo- cussed below could be used in deficient growth cases.metric tomograms that include the TMJ and posteriormandible can be extremely helpful in assessment of Treatment modalitiesjaw growth. Specialized radiography (eg, computed With any of the following surgical procedures, thetomography [CT] scans, magnetic resonance imaging preoperative rate of growth can be maintained after
American Journal of Orthodontics and Dentofacial Orthopedics Wolford, Karras, and Mehra 97Volume 119, Number 2Fig 1. The SSRO procedure can be used to (A and B) Fig 2. The ILO procedure can be used to advance theadvance the mandible or reposition it backward. mandible or reposition it backward. When used to advance the mandible, the gap created between proximal and distal segments requires grafting with bone or synthetic bone.surgery. These techniques should neither stimulate norhinder mandibular growth, provided that the TMJs arehealthy, the growth centers of the condylar heads arenot damaged, and the articular disks are not displacedas a result of surgery. The vector of facial and mandibu-lar growth, however, may be altered by a change in theorientation of the proximal segment, and thus thecondyle.16 With any of the following techniques, ifthe proximal segment is rotated forward, an increasedvertical growth vector will be seen after the operation.Likewise, rotation of the proximal segment backwardwill result in a more horizontal growth vector post-surgically. Compared with nonrigid fixation, the useof rigid fixation with all of the following techniqueswill improve immediate and long-term stability.17 Fig 3. The VRO procedure can be used to advance the Sagittal split ramus osteotomy. The sagittal split ramus mandible or reposition it backward. The coronoidosteotomy (SSRO)(Fig 1) is more difficult to perform on process limits the extent of movement. When used toyounger patients because of greater bony elasticity, the advance the mandible, the gap created between proxi-thinness of the cortical bone, the presence of unerupted mal and distal segments requires grafting with bone ormolar teeth, and the relatively shorter posterior vertical synthetic bone.mandibular body height, as compared with adults. It doeshave the advantages of easy application of rigid fixation aswell as better positional control of the proximal segment. mandible and vertically lengthen the ramus with appro- SSRO is best reserved for patients over the age of 12 priate bone or synthetic bone grafting as indicated toyears—that is, after the eruption of the permanent second control the positional orientation of the proximal seg-molars, so that damage to these teeth during surgery can ment and fill bony voids. The amount of mandibularbe avoided. Although the senior author (L.W.) has suc- advancement and vertical lengthening possible withcessfully performed this procedure on patients as young this technique is limited by the temporalis muscleas 8,12,13 we recommend waiting until at least age 12. attachment and interference of the coronoid processes Inverted “L” osteotomy. The inverted “L” osteotomy on the zygomatic arch. Thus, for larger movements a(ILO) (Fig 2) can be used to advance the mandible and ver- coronoidectomy may be needed, or the clinician maytically lengthen the ramus, but it may require bone or syn- need to revert to other surgical options.thetic bone grafting to control the positional orientation of The ILO and VRO can be performed on patients ofthe proximal segment and to fill the bony voids between virtually any age because the design of the osteotomiessegments. The use of rigid fixation is recommended. avoids developing teeth. However, care must be taken Vertical ramus osteotomy. The vertical ramus to avoid damage to developing teeth during applicationosteotomy (VRO) (Fig 3) can be used to advance the of rigid fixation.
98 Wolford, Karras, and Mehra American Journal of Orthodontics and Dentofacial Orthopedics February 2001 skeletal Class III relationship that becomes progressively more severe, or it begins as a Class I relationship and develops into a progressively worsening Class III rela- tionship. The accelerated mandibular growth outpaces the normal maxillary growth. Note that maxillary growth deficiency with normal or accelerated mandibular growth can create the same Class III jaw relationship, and it must be ruled out because the type and timing of treatment for that condition is different. Typically, the increase in the mandibular growth rate almost always occurs in the condyles (condylar hyperplasia) and can cause elonga- tion of the condylar neck and mandibular body, which leads to development of dental compensations. The con- dition often begins during the pubertal growth spurt, butFig 4. High condylectomy procedure (dotted line) with it may precede or succeed it, and the growth may con-articular disk repositioning provides a predictable tinue far beyond the normal growth period into the mid-method to stop mandibular growth, as well as good post- dle and even the late 20s. Growth can be accelerated uni-surgical TMJ function. laterally or bilaterally and can be in a horizontal or vertical vector (9:1 ratio). Other TMJ pathologies thatMandibular hyperplasia can cause unilateral excessive growth include osteochon- droma and fibrous dysplasia. Treatment considerations Mandibular hyperplasia is defined as a protrusive discussed here pertain to condylar hyperplasia.mandibular position resulting in Class III skeletal and There are essentially 3 options regarding the timingocclusal relationships. This condition may be ini- of surgery relative to growth (with option 3 being thetially seen with normal or accelerated mandibular authors’ preferred method of management).growth rates. Option 1 is to defer surgery until growth is com- When the clinician treats mandibular hyperplasia, plete. This may require delaying surgery until patientsthe patient’s tongue size and its position must be care- are in their middle to late 20s. Consequently, they mayfully evaluated before surgery. The most common have functional problems (mastication, speech),tongue-related factors affecting surgical results are esthetic disfigurement, pain, and psychosocial stigmasmacroglossia and habitual tongue placement. When the associated with a severe facial deformity.18,19 Addi-mandible is surgically moved posteriorly, the volume tionally, the magnitude of the deformity, if allowed toof the oral cavity decreases. An enlarged tongue or an become fully manifested by this delay in treatment,abnormal tongue-posturing habit may create postsurgi- may preclude an ideal result later. The hyperplasticcal relapse by causing forward posturing of the condyle condylar growth may result in severe deformation ofin the fossa, forward protrusion of the mandibular den- the mandible. Compensatory changes will occur in thetoalveolus, or shifting between segments that are wire maxilla, dentoalveolar structures, and associated softfixated. The use of a reduction glossectomy may be tissue structures, compromising the outcome and mak-indicated in specific cases.10 ing the result less than ideal. This is particularly true in Normal growth rate. In patients with normal cases of unilateral involvement, which can lead tomandibular growth rates, the mandible initiates its severe asymmetric deformities and can also result ingrowth from a forward position relative to the maxilla, TMJ internal derangement and dysfunction.or it is anatomically larger. With normal rates of max- Option 2 is to perform surgery to posteriorly posi-illary and mandibular growth, the same Class III jaw tion the mandible during growth, with overcorrectionrelationship is maintained throughout growth. This of the mandible. The accelerated growth can bedeformity can be corrected with various ramus expected to continue after surgery, and additionalosteotomies during growth with predictable and stable surgery will be necessary if the overcorrection is insuf-results. With these techniques, the rate of growth ficient or excessive. Early intervention may benefit theshould be unaltered by surgery and harmonious post- patient, however, relative to function, esthetics, andoperative maxillary and mandibular growth can be psychosocial concerns. If this alternative is chosen, theexpected, with maintenance of the surgical result. operation should be performed after the majority of Accelerated growth rate. In patients with accelerated maxillary growth is complete (girls, 14 years; boys, 17mandibular growth, the deformity usually begins as a years) to facilitate the estimation of overcorrection.
American Journal of Orthodontics and Dentofacial Orthopedics Wolford, Karras, and Mehra 99Volume 119, Number 2 Option 3 is to surgically eliminate further mandibulargrowth with a high condylectomy (Fig 4) and to simulta-neously correct the jaw deformity.20 Alternatively, thehigh condylectomy can be performed as stage 1 surgery,followed by orthognathic surgery at a later time. The highcondylectomy removes the active growth center(s), andthus prevents further mandibular growth. If orthognathicand TMJ surgery are performed concomitantly, the SSROis the procedure of choice because it maintains maximalsoft tissue attachments and thus vascularity to the proxi-mal segment. The ILO and VRO require increased strip-ping of periosteum and may lead to vascular compromiseof the proximal segment, in addition to causing difficul-ties with positional control of the condyle. Fig 5. Anterior mandibular subapical osteotomy allows repositioning of the dentoalveolus.Treatment modalities With any of the following mandibular ramus proce- with postsurgical occlusion.dures, the preoperative rate of growth can be expected The ILO and VRO can be performed on patients ofto be maintained after surgery. Mandibular growth virtually any age. Rigid fixation must be applied cau-should not be affected by any of these techniques, pro- tiously to avoid injury to developing teeth.vided that the condylar head is not damaged during High condylectomy. Surgically removing the supe-surgery. The vector of facial growth, however, may be rior 3 to 5 mm of the condylar head (Fig 4) will pre-altered by a change in the orientation of the proximal dictably stop anteroposterior and vertical growth of thesegment and thus the condyle. The use of rigid fixation mandible by removing the active growth center inwill improve long-term stability. condylar hyperplasia.20,21 Appositional mandibular Sagittal split ramus osteotomy. The SSRO (Fig 1) growth and dentoalveolar growth will not be affected.is more difficult to perform on younger patients TMJ function after surgery can be expected to remainbecause of the greater bony elasticity, the decreased normal if the condylar head is appropriately recontouredthickness of the cortical plates, the presence of and the articular disk is repositioned and stabilized in aunerupted molar teeth, and the relatively shorter pos- normal anatomical relationship between the condylarterior vertical mandibular body height in younger head and articular fossa. The Mitek bone anchor (Mitek,patients. It is the preferred technique when high Westwood, Mass) helps stabilize the repositioned disk tocondylectomy is performed simultaneously to stop the condylar head. Its use has significantly improved theexcessive mandibular growth, because maximum vas- predictability of disk repositioning surgery.cularity to the proximal segment is maintained. Rigid Except in select cases, this procedure should gener-fixation provides optimal long-term stability. Although ally be deferred until age 14 in girls and age 16 inthe SSRO is more difficult to perform than the ILO or boys—that is, when normal maxillary and mandibularVRO, it is the preferred technique because it allows for growth are closer to completion. Since no furthergood control of the condylar position. anteroposterior growth of the mandible can be SSRO is best reserved for patients over the age of expected after this procedure, continued maxillary12—that is, after the eruption of the permanent second growth usually results in a downward and backwardmolars, so that damage to these teeth during surgery growth vector for the maxillomandibular complex, butcan be avoided. the occlusion should remain stable. In unilateral cases, Inverted “L” osteotomy and vertical ramus the unoperated contralateral condyle will maintain nor-osteotomy. The ILO (Fig 2) and VRO (Fig 3) can be mal growth and could cause shifting of the mandibleused effectively to correct mandibular prognathism. toward the operated side. The severity of the deformity,The amount of mandibular set-back possible with the however, may warrant earlier surgery in some cases.VRO is limited by the temporalis muscle and the coro-noid process, unless a coronoidectomy is performed. ANTERIOR MANDIBULAR DENTOALVEOLARThe application of rigid fixation can be technically dif- DEFORMITIESficult for both types of osteotomies, particularly from Anterior mandibular dentoalveolar deformities havean intraoral approach. Without fixation, condylar posi- been defined as excessive, deficient, or asymmetric growthtion control may be inexact and can result in difficulties of the dentoalveolar structures. The condition may be due
100 Wolford, Karras, and Mehra American Journal of Orthodontics and Dentofacial Orthopedics February 2001 A B A BFig 6. Mandibular body osteotomy (A) allows positional Fig 7. Osseous genioplasty can be used to (A) augmentalteration in the body area. (B) Rigid fixation of seg- or reduce chin prominence. (B) Alloplastic implants canments is recommended. also be used to augment chin.to overdevelopment or underdevelopment of alveolar These osteotomies are often performed between adjacentbone, dental ankylosis, anodontia, premature tooth loss, teeth. Rigid fixation and precise surgery will produce themacroglossia, microglossia, habitual factors, or genetics. most predictable results. Care must be taken to maintain The mandibular growth rate should not be affected the integrity of the inferior alveolar and mental neurovas-by correction of these deformities unless adjacent teeth cular structures. It is recommended that this procedure beare damaged, which may result in dento-osseous anky- deferred until after the age of 12 years to minimize thelosis, a condition that will impair subsequent vertical risk of injury to the developing dental structures.alveolar growth. CHIN DEFORMITIESTreatment modalities Deformities of the chin include excessive (macroge- Anterior mandibular subapical osteotomy. The ante- nia) or deficient (microgenia) development. Chin defor-rior mandibular subapical osteotomy (Fig 5) involves 2 mities can occur in all 3 planes of space and can thereforevertical interdental osteotomies joined inferiorly by a affect the height, width, and anteroposterior dimensionshorizontal osteotomy 4 to 5 mm below the tooth apices. of the anterior mandible. The treatment for macrogeniaThe segment is placed in the desired position and stabi- may involve osseous recontouring or spatial reorientationlized, ideally with rigid fixation.22 Preoperative ortho- of the chin with osteotomy techniques. Microgenia maydontic treatment may be required to create adequate likewise be treated by altering chin position withspace between the roots of the teeth to safely complete osteotomies or with a graft, using bone, synthetic bonethe interdental osteotomies. To avoid damage to the roots substitutes, or alloplastic implants. In younger patients inof developing teeth, which could result in ankylosis and the mixed dentition there is an inherent risk of damage toalveolar growth impairment, this procedure should be developing teeth and to the mental nerves that closelydeferred until eruption of adjacent teeth in this region is approximate the inferior border of the mandible. Aug-essentially complete (ie, when the patient is over age 12). mentation genioplasty with alloplastic implants that do not cause resorption of underlying bone can be performedMANDIBULAR BODY DEFORMITIES at an earlier age, provided the implant can be stabilized Mandibular body deformities are defined as excessive, without risk of injury to underlying dental structures.deficient, or asymmetric development of the mandibularbody. Correction of these deformities during growth Treatment modalitiesshould have no effect on subsequent mandibular growth, Osseous genioplasty. Various techniques are availableunless adjacent teeth are ankylosed or the developing teeth for altering the dimensions of the chin by osteotomies (Figare damaged, leading to dento-osseous ankylosis, which 7, A), including sliding horizontal osteotomy and the tenonwill result in impaired vertical alveolar growth. and mortise technique.23,24 Bone segments may be fixed with wires, bone screws, or bone plates, and may requireTreatment modalities bone or synthetic bone grafting, as in the case of vertical Mandibular body osteotomy. A mandibular body lengthening. These procedures have no significant effectprocedure (Fig 6) involves 1 or more osteotomies, on subsequent facial growth, with the exception of affect-extending the full vertical height of the mandibular body. ing appositional bone growth at pogonion, or if developing
American Journal of Orthodontics and Dentofacial Orthopedics Wolford, Karras, and Mehra 101Volume 119, Number 2dental structures are injured, which may lead to dentoalve- 7. Reiche-Fischel O, Wolford LM. Changes in temporomandibularolar ankylosis and decreased vertical alveolar growth. The joint dysfunction after orthognathic surgery [Abstract}. Pro- ceedings of the Americal Association of Oral and Maxillofacialpatient must be at a level of dento-osseous development Surgeons 78th Annual Meeting; 1996 Sep 18-22; Miami, Fl J(ie, 12 years old or older), that will minimize the risk of Oral Maxillofac Surg 1996;54:84.damage to underlying teeth and neurovascular structures. 8. Fuselier JC, Wolford LM, Pitta M, Talwar RM. Condylar Augmentation genioplasty with alloplasts. Alloplasts changes after orthognathic surgery with untreated TMJ derange-(Fig 7, B) that are proved not to cause bone resorption ment. Proceedings of the American Association of Oral and Maxillofacial Surgeons 80th Annual Meeting; 1998 Sep 16-20;(porous block hydroxyapatite,25 and HTR26) can be New Orleans, LA. J Oral Maxillofac Surg 1998;56:61-62.placed in patients as early as age 8 or 9 to the early teens, 9. Proffit WR, Mason RM. Myofunctional therapy for tongue-provided they can be fixed to the bone without damage thrusting: background and recommendations. J Am Dent Assocto underlying dental or neurovascular structures. Appo- 1975;90:403-11.sitional growth at pogonion will be eliminated after 10. Wolford LM, Cottrell DA. Diagnosis of macroglossia and indi-placement of these implants. Certain alloplastic materi- cations for reduction glossectomy. Am J Orthod Dentofacial Orthop 1996;110:170-7.als, (Proplast-Teflon [Vitek, Houston, Texas], Silastic 11. Emrich RE, Brodie AG, Blayney JR. Prevalence of Class I, Class[Dow Corning, Midland, Mo], and acrylic), have been II, and Class III malocclusions (Angle) in an urban population:documented to cause resorption of underlying bone, and an epidemiological study. J Dent Res 1965;44:947.their use is discouraged.25 Although certain alloplastic 12. Wolford LM, Schendel SA, Epker BN. Surgical-orthodontic cor-implants can be placed when the patient is 10 years old rection of mandibular deficiency in growing children: long-term treatment results. J Maxillofac Surg 1979;7:61-72.or younger, it is best to wait until the patient is at least 12 13. Schendel SA, Wolford LM, Epker BN. Mandibular deficiency syn-to minimize the risk of damage to underlying teeth and drome: part III, surgical advancement of the deficient mandible inneurovascular structures. growing children: treatment results in twelve patients. Oral Surg Oral Med Oral Path Oral Radiol Endod 1978;45:364-77.CONCLUSIONS 14. Snow MD, Turvey TA, Walker D, Proffit WR. Surgical mandibu- lar advancement in adolescents: postsurgical growth related to Pediatric and adolescent patients with dentofacial stability. Int J Adult Orthodon Orthognath Surg 1991;6:143-51.deformities may, at times, require surgical treatment 15. Huang CS, Ross RB. Surgical advancement of the retrognathicduring active growth because of functional, esthetic, mandible in growing children. Am J Orthod 1982;82:89-102.and psychosocial factors. A good understanding of 16. Epker BN, O’Ryan F. Effects of early surgical advancement offacial growth, available treatment options, and the the mandible on subsequent growth, part II: biomechanical con- siderations. In: The effect of surgical intervention on craniofa-effects of surgery on postoperative growth patterns will cial growth. McNamara JA, Carlson DS, Ribbens KA, editors.help the clinician improve treatment outcomes for Ann Arbor: University of Michigan; 1982. p. 207-29.these patients. Serial clinical, dental model, and radi- 17. Satrom KD, Sinclair PM, Wolford LM. The stability of doubleographic analyses are important in predicting growth jaw surgery: a comparison of rigid versus wire fixation. Am Jrates and patterns for individual patients. Orthod Dentofacial Orthop 1991;99:550-63. The material presented in this article is based on 18. Bruce RA, Haywood JR. Condylar hyperplasia and mandibular asymmetry: a review. J Oral Surg 1968;26:281-2.available research information and extensive personal 19. Beirne OR, Leake DL. Technetium 99m pyrophosphate uptake inclinical experience. It is not meant to be absolute— a case of unilateral condylar hyperplasia. J Oral Surg 1980;instead, it should serve as a guide to formulate a spe- 38:385-6.cific treatment plan for each individual growing patient 20. Wolford LM, LeBanc J. Condylectomy to arrest disproportionatewith respect to the appropriate type and timing of cor- mandibular growth. Proceedings of the American Cleft Palate Association Annual Meeting; 1986 May 16-19; New York, NY.rective surgical procedures on the mandible. Chapel Hill (NC):American Cleft Palate Association;1986.REFERENCES 21. Obwegeser HL, Makek MS. Hemimandibular hyperplasia— hemi- mandibular elongation. J Craniomaxillofac Surg 1986;14:183-5. 1. Broadbent BH Sr, Broadbent BH Jr, Golden WH. Bolton standards 22. Wolford LM, Moenning JE. Diagnosis and treatment planning for of dentofacial developmental growth. St Louis: CV Mosby; 1975. mandibular subapical osteotomies with new surgical modifications. 2. van der Linden F. Facial growth and facial orthopaedics. Surrey, Oral Surg Oral Med Oral Path Oral Radiol Endod 1989;68:541-50. UK: Quintessence; 1986. 23. Wessberg GA, Wolford LM, Epker BN. Interpositional genio- 3. Leggett J. The human face. London: Constable; 1974. plasty for the short face syndrome. J Oral Surg 1980;38:584-90. 4. Mac Gregor FC. Transformation and identity. New York: Quad- 24. Wolford LM, Bates JD. Surgical modification for the correction rangle; 1974. of chin deformities. Oral Surg Oral Med Oral Path Oral Radiol 5. Adams GR. Physical attractiveness. In: Miller A, editor. In the Endod 1988;66:279-86. eye of the beholder: contemporary issues in stereotyping. New 25. Moenning JE, Wolford LM. Chin augmentation with various York: Paeger; 1982. p. 252. alloplastic materials: a comparative study. Int J Adult Orthod 6. Alley TR. Physiognomy and social perception. In: Alley TR, edi- Orthognath Surg 1989;4:175-87. tor. Social and applied aspects of perceiving faces. Hillsdale 26. Karras SC, Wolford LM. Augmentation genioplasty with hard tis- (NJ): Lawrence Erlbaum Associates; 1988. p. 167. sue replacement implants. J Oral Maxillofac Surg 1998; 56:549-52.