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Background: Despite advances in surgical technique, reconstruction of a mandibular condyle still causes significant donor-site morbidity. The purpose of this study was to compare the effect of 3 different growth factors and define optimal cell culture conditions for bone marrow-derived progenitor cells to differentiate into chondrocytes for mandibular condyle reconstruction., Methods: Porcine bone marrow-derived progenitor cells (pBMPCs) were cultured as a pellet for 2, 3, and 4 weeks under the following conditions: group 1, TGF-β3 + standard medium; group 2, TGF-β3 + BMP-2 + standard medium; group 3, TGF-β3 + IGF-1 + standard medium; and group 4, TGF-β3 + BMP-2 + IGF-1 + standard medium. Chondrogenic differentiation was evaluated using 3 lineage differentiation markers., Results: The mean type II collagen positive area increased over weeks 2, 3, and 4 in group 4 compared to all the other groups (ANOVA; P = 0.005). At week 4, there was significantly greater type II collagen production in group 4 compared to all the other groups (ANOVA; P = 0.003). The medium in group 4 produces the greatest amount of cartilage when compared to groups 1, 2, and 3, and that 4 weeks produces the greatest amount of type II collagen., Conclusions: The results of this study indicate that the most efficacious medium for chondrogenic differentiation of pBMPCs was group 4 medium and the most type II collagen was produced at 4 weeks.

Purpose: To develop and test a novel, hydraulic, continuous, automated distraction device capable of 3D movements for treatment of mandibular deformities., Materials and Methods: We used 2 cadaveric and 5 live female Yucatan minipigs to test the distractor. The 3 components (miniature buried distractor, external power and control box, and user interface on handheld computer) operate on a closed loop in which the hydraulic pulse strength correlates with the resistance of the bone and soft tissue. The system auto-adjusts to correct any discrepancy between the actual and desired position of mandibular fragments. The distraction protocol included 0-day latency, 1 mm (divided into 94 increments) per day, and 24 days' fixation. Clinical examination was performed and lateral and anteroposterior cephalometric radiographs were obtained preoperatively and postoperatively, at mid distraction osteogenesis (DO), end DO, and end fixation. Position information was obtained through the user interface., Results: Both cadaveric trials resulted in the desired distraction gap (11 to 12 mm), with all components functioning as designed. In 4 of the 5 live animals, distraction averaged 7.29 mm (range, 5 to 11 mm) over 12 days of activation. In 3 of the 5 live animals, the osteotomy gap filled in with bone by 24 days of fixation. Two animals were sacrificed prematurely (1 at mid DO and 1 at end DO) because vital components malfunctioned., Conclusions: The device is capable of automated, continuous, hydraulically powered DO at a rate of 1 mm/d. Future work will be directed at fortifying the device components and testing it in larger numbers of animals at varying distraction rates., (Copyright © 2013 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: Auriculocondylar syndrome (ACS) is a rare craniofacial disorder consisting of micrognathia, mandibular condyle hypoplasia and a specific malformation of the ear at the junction between the lobe and helix. Missense heterozygous mutations in the phospholipase C, β 4 (PLCB4) and guanine nucleotide binding protein (G protein), α inhibiting activity polypeptide 3 (GNAI3) genes have recently been identified in ACS patients by exome sequencing. These genes are predicted to function within the G protein-coupled endothelin receptor pathway during craniofacial development., Results: We report eight additional cases ascribed to PLCB4 or GNAI3 gene lesions, comprising six heterozygous PLCB4 missense mutations, one heterozygous GNAI3 missense mutation and one homozygous PLCB4 intragenic deletion. Certain residues represent mutational hotspots; of the total of 11 ACS PLCB4 missense mutations now described, five disrupt Arg621 and two disrupt Asp360. The narrow distribution of mutations within protein space suggests that the mutations may result in dominantly interfering proteins, rather than haploinsufficiency. The consanguineous parents of the patient with a homozygous PLCB4 deletion each harboured the heterozygous deletion, but did not present the ACS phenotype, further suggesting that ACS is not caused by PLCB4 haploinsufficiency. In addition to ACS, the patient harbouring a homozygous deletion presented with central apnoea, a phenotype that has not been previously reported in ACS patients., Conclusions: These findings indicate that ACS is not only genetically heterogeneous but also an autosomal dominant or recessive condition according to the nature of the PLCB4 gene lesion.

Purpose: To differentiate between temporomandibular joint (TMJ) inflammation and myofascial pain (MPD) in children with juvenile idiopathic arthritis (JIA)., Patients and Methods: We performed a retrospective study of children with JIA evaluated at Boston Children's Hospital, Boston, Massachusetts. Patients, aged 16 years or younger at the time of diagnosis, were included if they had confirmed JIA with jaw signs or symptoms. Medical records and imaging studies were reviewed to document demographic, clinical, and radiographic findings. Patients with clinical evidence (joint pain/tenderness, asymmetry, limited motion) and radiographic evidence (condylar asymmetry, flattening, accentuated antegonial notch) of TMJ inflammation but without muscle pain were diagnosed with arthritis. Those with only muscle tenderness and/or limited jaw motion were diagnosed with MPD. Patients with TMJ inflammation and muscle pain/tenderness were considered to have co-existing arthritis and MPD. Outcome variables were the presence of TMJ arthritis and/or MPD. Descriptive statistics were computed., Results: There were 61 patients (44 girls) with a mean age of 12.7 years (range, 3 to 16 years) who met the inclusion criteria. The most common clinical findings were limited mouth opening (n = 24), malocclusion/asymmetry (n = 23), and/or tenderness to palpation (n = 18). Twenty-one patients had multiple signs and symptoms. Panoramic radiographs showed condylar abnormalities in 32 patients. Overall, 21 patients (34.4%) were diagnosed with active TMJ arthritis, 21 (34.4%) with MPD, and 11 (18%) with both arthritis and MPD. Of the patients, 8 (13.1%) were in remission., Conclusions: The results of this study indicate that in patients with JIA and jaw signs/symptoms, there is an overlap in diagnoses between arthritis and MPD. This has considerable implications for patient management., (Copyright © 2013 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Purpose: To document tumor type, biological/clinical behavior, management, and outcomes in children with primary jaw tumors., Materials and Methods: A retrospective analysis of children with primary benign jaw tumors evaluated at Massachusetts General Hospital and Children's Hospital Boston from 1991 to 2009 was conducted. Patients were included if they were aged 16 years or younger and had adequate records and follow-up. Patient charts, radiographs, and pathology reports were reviewed. Demographic data; clinical, radiographic, and histopathologic findings; treatment; and outcomes were recorded. Predictor variables were tumor type, clinical behavior (nonaggressive/aggressive), and treatment. Outcome variables included presence or absence of recurrence and complications. Descriptive statistics were computed., Results: There were 102 patients (44 male and 58 female patients) with a mean age of 8.3 years (range, 6 months to 16 years). Tumors were grouped by tumor type: mesenchymal (n=96), neurogenic (n=5), vascular (n=5), or hematopoietic (n=3); in addition, when appropriate, they were classified as nonaggressive (n=54) or aggressive (n=27). Treatment was based on the tumor's clinical/biological behavior and radiographic features and whether it was solitary or multifocal. Patients with nonaggressive tumors were treated by enucleation, debulking/contouring, or observation, and the recurrence rate was 0%. Aggressive tumors underwent en bloc resection or enucleation with systemic adjuvant therapy, and the recurrence rate was 7.1%. Mean follow-up was 2.4 years., Conclusions: The results of this study indicate that primary jaw tumors in children exhibit variable biological/clinical behavior, often not predicted by descriptive histologic findings. Management of these tumors should therefore be guided by clinical/biological behavior., (Copyright © 2013 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Purpose: The objective of this study was to identify factors associated with the conversion of scientific abstracts to publications in peer-reviewed journals., Methods: This was a retrospective study of abstracts presented by members of the Massachusetts General Hospital Department of Oral and Maxillofacial Surgery between 2000 and 2010. Predictor variables were categorized as abstract- or author-specific. The outcome variable was conversion of an abstract presented at a meeting to a published manuscript. Descriptive, bivariate, and multiple regression statistics were computed. P < 0.05 was significant., Results: The sample was composed of 122 abstracts presented at meetings. Ninety abstracts (73.8%) were published in a peer-reviewed literature within 5 years of presentation. The mean time between presentation to publication was 21.9 ± 17.3 months (median, 19.0 months; range, 0-99 months). In bivariate analyses, study design, number of prior publications by the presenting author, and number of prior publications by the senior author were associated with time to publication (P < 0.06). In a multiple Cox proportional hazards model, higher levels of evidence (hazard ratio, 1.2; 95% confidence interval, 1.04-1.3; P = 0.006) and volume of prior publications by the senior author (hazard ratio, 1.007; 95% confidence interval, 1.003-1.011; P < 0.001) were associated with shorter publication times., Conclusions: Time to publication of scientific abstracts is associated with study quality, prior research experience by the presenting author, and senior author identity and experience.

Purpose: To assess the 3-dimensional (3D) computed tomography (CT) changes in airway size and shape in children with congenital micrognathia treated by mandibular distraction osteogenesis (DO)., Patients and Methods: This was a retrospective study of patients with congenital micrognathia, treated by mandibular DO, who had pre- and postoperative 3D maxillofacial CT scans from the hard palate to the hyoid bone. Digital 3D-CT reconstructions were made before and after distraction. Demographic (age, gender, and diagnosis) and anatomic (airway size and shape) variables were recorded and analyzed. The pre-distraction measures of size and shape were compared with the post-distraction measures. P≤.05 was considered significant., Results: During the study period (1999 to 2010), 17 children with congenital micrognathia underwent mandibular DO. Of these patients, 11 (3 females) met the inclusion criteria. The mean age was 6.8 years (range 1.3 to 20.6). All subjects had first and second pharyngeal arch deformities. Nine were tracheostomy dependent before distraction. Postdistraction increases in the anteroposterior diameter (153%), lateral airway diameter (70%), airway volume (76%), minimal retroglossal (162%) and retropalatal (77%), and minimal cross-sectional areas (282%) were obtained. The mean airway length decreased after distraction by 4 mm DO also affected the airway shape: the airway surface area and airway compactness increased after distraction. Six subjects were decannulated or had their tracheostomies capped. Three subjects remained tracheostomy dependent after distraction. The reasons for continued tracheostomy included copious secretions, muscle hypotonia, hypopharnygeal stenosis, and mandibular hypomobility., Conclusions: DO for congenital micrognathia increases airway size, decreases airway length, and alters the shape as measured using 3D-CT., (Copyright © 2013 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Purpose: To identify factors associated with functional sensory recovery (FSR) after lingual nerve repair., Materials and Methods: This retrospective cohort study was composed of subjects who underwent lingual nerve repair from 2004 through 2010. The predictor variables were demographic, anatomic, and operative measurements. The primary outcome measurement was FSR (ie, FSR achieved, yes or no). The secondary outcome measurements were time to FSR and an improvement of at least 2 levels on the British Medical Research Council scale of neurosensory function. Descriptive, bivariate, and multiple logistic regression statistics were computed to identify associations between the predictor variables and FSR. A Cox proportional hazards model was used to identify associations between the predictors and time to FSR. P ≤ .05 was considered statistically significant., Results: The sample was composed of 55 subjects with a mean age of 30.7 ± 11.2 years. The mean duration from injury to repair was 151.6 days (range, 41 to 384 days). Most patients (74.5%) achieved FSR postoperatively, with a mean time to FSR of 262.8 days (median, 208 days). Eighty-six percent of subjects showed an improvement of at least 2 levels on the British Medical Research Council scale. In multiple regression models, younger subjects were more likely to achieve FSR (odds ratio, 1.10; 95% confidence interval, 1.01 to 1.18; P = .02); subjects with better preoperative neurosensory function achieved FSR faster (hazard ratio, 1.9; 95% confidence interval, 1.2 to 3.1; P = .01)., Conclusion: Most patients undergoing lingual nerve repair achieved FSR. Younger subjects were more likely to achieve FSR. Subjects with better preoperative neurosensory function achieved FSR faster., (Copyright © 2012 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Purpose: To determine whether the clinical behavior of giant cell lesions (GCLs) or their anatomic location can be differentiated by histologic criteria alone., Materials and Methods: We performed a retrospective study of patients with GCLs treated at Massachusetts General Hospital between 1993 and 2008. Predictor variables were histologic parameters: number of giant cells (GCs) per high-power field, number of nuclei per GC, GC size, stromal cellularity, stromal type, presence of hemorrhage and reactive osteoid, and blinded pathologists' prediction of location and behavior. Outcome variables were clinical behavior (aggressive or nonaggressive) and GCL location, that is, maxillofacial (MF) or axial/appendicular (AA). Descriptive and bivariate statistics were computed with statistical significance set at P ≤ .05., Results: The sample included 88 subjects: 41 MF GCLs (35 aggressive) and 47 AA GCLs (28 aggressive). Aggressive AA lesions had more GCs per high-power field, larger mean GC size, and increased stromal cellularity, and they more frequently had a mononuclear stroma when compared with aggressive MF lesions (P < .05). There were no significant histologic differences between aggressive and nonaggressive MF lesions or between nonaggressive MF and nonaggressive AA lesions. Aggressive AA lesions had more nuclei/GC than nonaggressive AA lesions (P = .03). Using histologic criteria only, blinded pathologists predicted clinical behavior in only 45% of cases (κ = 0.19, P = .09). They predicted a lesion's location in 82% of cases with fair agreement (κ = 0.44, P < .01)., Conclusions: Results of this study indicate that histologic differences between aggressive and nonaggressive GCLs are insufficient for pathologists to differentiate them consistently regardless of location., (Copyright © 2012 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Purpose: To document the sequence of bone formation in a minipig model of Le Fort I distraction osteogenesis (DO) using immunohistochemistry and histomorphometry., Materials and Methods: Female Yucatan minipigs (N = 9) in the mixed-dentition stage underwent bilateral maxillary DO. The distraction protocol was 0 days of latency, with a distraction rate of 1 mm/d for 12 days and 24 days of fixation. Specimens were harvested and divided between the central incisors (18 hemi-maxillae) at the end of DO (n = 6), at mid-fixation (n = 6), and at the end of fixation (n = 6). Sections, including the advancement zone, were stained with hematoxylin-eosin, collagen II, CD34, proliferating cell nuclear antigen, and tartrate-resistant acid phosphatase. Light and fluorescence microscope images (original magnification ×200) were obtained, and percentage of surface area (PSA) of the advancement zone occupied by fibrous tissue, vessels, proliferating cells, osteoid, and bone was determined. An intact maxilla served as the control., Results: At the end of DO, in the advancement zone, the PSA (mean values) of proliferating cells was 33.16%; fibrous tissue, 52%; vessels, 4.35%; and new bone, 5.45%. At the end of fixation, the PSA of proliferating cells decreased to 10.53%, fibrous tissue to 2.3%, and vessels to 1.5% whereas the PSA of new bone increased to 44.9%., Conclusions: The results of this study indicate that the progression of osteogenesis in the maxillary DO wound begins with intense cellular proliferation and vascular fibrous tissue formation and progresses to mature, cancellous bone by the end of fixation. The PSA occupied by mature bone is significantly less than in the control maxilla at the end of fixation. This is consistent with the sequence in the mandibular DO wound., (Published by Elsevier Inc.)

Purpose: To describe a novel technique using custom prostheses to repair fractured mandibular reconstruction plates spanning discontinuity defects., Materials and Methods: This is a retrospective case series reviewing the design, rapid manufacture, and use of a novel method to repair fractured plates. Three patients who could not undergo autogenous bone grafting procedures or replacement of the entire plate for medical or socioeconomic factors were treated by this method., Results: Three patients with fractured reconstruction plates were treated with a custom prosthesis engaging the reconstruction plate. Continuity and function were restored with a minimally invasive operation and short hospital stay. The custom prosthesis remained in place with stable occlusion in all 3 patients at a minimum of 9 months' follow-up., Conclusions: A technique using a custom prosthesis to quickly and less invasively restore continuity and function of the mandible after fracture of a reconstruction plate is described., (Copyright © 2012 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Purpose: Controversy exists as to the most appropriate treatment strategy for myofibromas of the jaws: en bloc resection versus enucleation. The purpose of the present study was to evaluate the treatment outcomes in children with these uncommon benign tumors., Materials and Methods: We performed a retrospective chart review of pediatric patients with jaw myofibromas. The predictor variables included patient demographics, clinical presentation, imaging characteristics, pathologic features, treatment, and follow-up. The outcome variable was cure or recurrence. The descriptive statistics were computed., Results: A total of 12 patients (mean age 6.7 years) met the inclusion criteria. There were 2 presentations: exophytic soft tissue mass in dentoalveolar segment (n = 5); and intraosseous mass (n = 7). No distinct histopathologic differences were found between the 2 groups. Exophytic myofibromas displayed rapid growth, tooth displacement and/or mobility, bony expansion, and/or cortical thinning/perforation. Most were treated by resection. The intraosseous lesions were asymptomatic and/or incidentally discovered. They were treated by enucleation and curettage. The mean follow-up for the 2 groups was 6.5 and 3.9 years, respectively. There were no recurrences., Conclusions: The results of the present study indicate that there are 2 clinical presentations of myofibromas of the jaws in children: an aggressive exophytic type and a nonaggressive intraosseous type. They are histopathologically indistinguishable., (Copyright © 2012 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

This study characterized sequential molecular and cellular events in the porcine mandibular distraction osteogenesis (DO) wound. Nineteen Yucatan minipigs were divided into three treatment groups: Group A, unilateral mandibular distraction with 0 day latency, 1mm/day rate for 12 days, 24 days fixation (n=16); Group B, acute lengthening 12 mm (n=2); Group C, sham control (n=1). Group A was further divided by death date: mid-DO (n=5), end-DO (n=4), mid-fixation (n=5) and end-fixation (n=2). Groups B and C were killed on postoperative day 36, corresponding to end-fixation. Specimens were stained for proliferating cell nuclear antigen (PCNA) and bone morphogenetic protein-4 (BMP4). Cellular proliferation (PCNA) was assessed quantitatively and BMP4 staining was assessed on a semi-quantitative scale. Progenitor cell proliferation was greatest during mid-DO and decreased from end-DO through end-fixation. Proliferation in the acute lengthening group was elevated relative to sham control and comparable to end-DO. BMP4 staining intensity (localized to the periosteal cambium layer) was greatest during mid- and end-DO, decreased at mid-fixation and was undetectable at end-fixation. Progenitor cell proliferation and BMP4 expression are greatest during mid-DO and decrease progressively thereafter. At the time of death of the acute lengthening group, only increased cell proliferation was demonstrated., (Copyright © 2011 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

Cherubism is a skeletal dysplasia characterized by bilateral and symmetric fibro-osseous lesions limited to the mandible and maxilla. In most patients, cherubism is due to dominant mutations in the SH3BP2 gene on chromosome 4p16.3. Affected children appear normal at birth. Swelling of the jaws usually appears between 2 and 7 years of age, after which, lesions proliferate and increase in size until puberty. The lesions subsequently begin to regress, fill with bone and remodel until age 30, when they are frequently not detectable.Fibro-osseous lesions, including those in cherubism have been classified as quiescent, non-aggressive and aggressive on the basis of clinical behavior and radiographic findings. Quiescent cherubic lesions are usually seen in older patients and do not demonstrate progressive growth. Non-aggressive lesions are most frequently present in teenagers. Lesions in the aggressive form of cherubism occur in young children and are large, rapidly growing and may cause tooth displacement, root resorption, thinning and perforation of cortical bone.Because cherubism is usually self-limiting, operative treatment may not be necessary. Longitudinal observation and follow-up is the initial management in most cases. Surgical intervention with curettage, contouring or resection may be indicated for functional or aesthetic reasons. Surgical procedures are usually performed when the disease becomes quiescent. Aggressive lesions that cause severe functional problems such as airway obstruction justify early surgical intervention.

Purpose: The purpose of this study was to evaluate porcine bone marrow-derived progenitor cell (pBMPC) proliferation and penetration into a novel 3-dimensionally printed scaffold., Materials and Methods: Four different tissue engineering scaffolds to evaluate pBMPC proliferation and penetration were examined. Scaffolds were fabricated from polycaprolactone (PCL) or the combination of β-tricalcium phosphate (β-TCP) and PCL (50:50), with 2 separate channel sizes (1 mm [small (S)] vs 2 mm [large (L)]). Scaffolds were fabricated into 20 × 20 × 7-mm blocks by use of a TheriForm machine (Integra Life Sciences, Akron, OH). Four groups of scaffolds were examined for pBMPC proliferation and penetration: group 1, β-TCP/PCL S; group 2, β-TCP/PCL L; group 3, PCL S; and group 4, PCL L. Nonparametric mean (Kruskal-Wallis) and multiple comparisons tests were used to compare the 4 groups., Results: No shrinkage or deformation was noted in any of the scaffold groups after 2 weeks of culture. Mean surface cell counts ranged from 13.4 to 87.8 cells/0.57 mm(2), with group 1 (β-TCP/PCL S) having statistically significantly higher counts than the other groups (P < .001). Mean interior cell counts ranged from 10.9 to 75.6 cells/0.57 mm(2), with group 1 having the greatest interior cell count (P < .001). Total collagen formation ranged from 0.2% to 86%, with group 1 having the highest collagen formation (P < .001)., Conclusions: The 3-dimensionally printed scaffold (β-TCP/PCL) with 1-mm channels showed greater cellular proliferation, penetration, and collagen formation after a 2-week in vitro culture than the other scaffolds evaluated. β-TCP/PCL S scaffolds warrant further evaluation for bone tissue engineering in vivo., (Copyright © 2012 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

The purpose of this project was to test a surgical navigation tool designed to help execute a surgical treatment plan. It consists of an electromagnetically tracked pencil that is used to mark bone intraoperatively. The device was tested on a precision block, an ex vivo pig mandible and during performance of six endoscopic vertical ramus osteotomies on pig cadavers. The difference between actual pencil position and that displayed by the computer was measured three times each at ten 2mm holes on the block (n=30 observations) and on the ex vivo mandible (n=11 measurements). Errors between planned and actual osteotomy locations for the cadaver procedures were measured. The mean distance between known and displayed locations was 1.55 ± 0.72 mm on the precision block and 2.10 ± 0.88 mm on the pig mandible. The error measured marking the same point on the block multiple (n=5) times was 0.58 ± 0.37 mm. The mean error on the simulated osteotomies was 2.35 ± 1.35 mm. Osteomark was simple to use and permitted localisation of holes and osteotomies with acceptable accuracy. In the future, the device and algorithms will be revised to further decrease error and the system will be tested on live animals., (Copyright © 2011 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

Following encouraging results from the first 6 maxillofacial allotransplants, there has been a dramatic rise in interest worldwide. Numerous groups are now devoting resources to increase the frequency of these complex procedures, and with this, the craniomaxillofacial surgeon should become familiar with the emerging state of the art. This article reviews the evolution of Le Fort-based cadaveric studies pertaining to maxillofacial allotransplantation, briefly describes the clinical reports through 2010, and introduces a refined technique applying orthognathic applications. Preliminary studies over the last 5 years have highlighted the challenges associated with transplanting skeletal components, and clinical results presented thus far have been extremely promising. However, a notable area for improvement is suboptimal facial-skeletal harmony and profile in the context of sagittal skeletal projection and maxillomandibular relation. To our knowledge, orthognathic planning as applied to osteocutaneous face transplantation has not been described. Many recipients seen thus far demonstrate some degree of malocclusion and suboptimal harmony, as expected, given the donor-to-recipient skeletal/jaw discrepancies. Given that the goal is to improve function as well as form, the importance of orthognathic planning cannot be overstated with respect to optimizing harmony, profile, and occlusion. Preoperative planning, including generation of donor/recipient dental cast models, as described herein for the first time, is essential.

Background: Osteocutaneous maxillofacial allotransplantation is an encouraging technique for reconstruction of complex midfacial injuries (i.e., Gordon type III composite tissue allotransplantation). Although clinical results have been promising, there are no published guidelines, to date, on how to establish a functional occlusion and class I skeletal relation between the donor maxilla and recipient mandible. The purpose of this study was to use orthognathic principles and practice to improve occlusal and facial skeletal outcomes in osteocutaneous maxillofacial allotransplantation., Methods: Three Le Fort III-based maxillofacial allotransplantations were performed, using six fresh cadavers. Each recipient was prepared bluntly simulating a massive, bilateral orbitozygomatic maxillofacial defect. The first transplant was completed according to published protocol. The second was planned using dental cast models, cephalometric analyses, model surgery, and occlusal splint fabrication. The third involved an edentulous scenario, with the donor alloflap fixated to the recipient's mandible using a mimic Gunning splint to establish the vertical dimension of occlusion., Results: All three operations resulted in facial aesthetics comparable to those seen with autologous methods. Operative times ranged from 3.5 to 5.3 hours. The first allotransplant resulted in a class II malocclusion (overjet, 5 mm). The second recipient, with a preexisting class II skeleton, displayed a small anterior open bite of -1.7 mm, 1 mm of overjet, and a class I skeletal relationship (A-point-nasion-B-point angle, 2.3 degrees) following transplantation. The final transplant, consisting of an edentulous alloflap to an edentulous recipient, demonstrated an orthognathic profile., Conclusion: Use of orthognathic principles and practice in osteocutaneous maxillofacial allotransplantation resulted in improved occlusion, skeletal projection, and facial harmony relative to standard technique.

A recent radiographic study of an Egyptian mummified head from the Middle Kingdom revealed methodical mutilations of the facial skeleton that were performed after death and prior to wrapping the corpse for burial. These mutilations consisted of removal of the coronoid processes of the mandible and portions of the zygomas presumably via an intraoral approach. They are unique in the archaeological record. The authors hypothesize that the procedures were carried out to facilitate jaw opening and may be related to a ritual known as the 'Opening of the Mouth' ceremony. The purpose of this study was to demonstrate the feasibility of performing these remarkable osteotomies on two human cadavers using instruments similar to those available to the ancient embalmer. Bilateral osteotomies of the zygomas and coronoid processes were carried out transorally and the bones removed. Pre- and postoperative maximal incisal opening measured 25 mm and 53 mm, respectively. Postoperative high-resolution computed tomographic (CT) scans were obtained. Comparison of the postoperative cadaver and mummy CT scans demonstrate remarkable similarity between the resections. Results of this study demonstrate that the ancient skeletal mutilations could have been performed transorally during the mummification process and would have enhanced jaw opening., (Copyright © 2011 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

Coronoid process hyperplasia is a rare cause of mandibular hypomobility. It can result from temporalis muscle hyperactivity, trauma, and neoplasia, but often is idiopathic. Enlargement of the coronoid process leading to pseudojoint formation with the zygomatic arch is known as Jacob's disease. It results most commonly from an osteochondroma of the coronoid process. This is the first reported case of a non-neoplastic accessory mandibular condyle located at the coronoid process articulating with the zygoma.

Purpose: To evaluate patient, tumor, and treatment variables associated with survival in patients with jaw osteosarcoma (JOS) and to compare survival in patients treated before 1991 with those managed with more aggressive treatment protocols since 1992., Patients and Methods: This is a retrospective cohort study of patients with JOS treated at Massachusetts General Hospital from 1967 through 2007. Patients were divided by treatment date into Group 1, 1967 to 1991 (n = 30) and Group 2, 1992 to 2009 (n = 17). Medical records were reviewed to collect the following: demographic, radiographic, tumor-specific, treatment, and survival data. The 2 subgroups were statistically compared., Results: There were 47 patients (32 males, 15 females) with a mean age of 30.9 years (range 4 to 74). Mandibular location showed a trend toward improved survival (P = .06). Average tumor size was 4.38 cm (range 0.5 to 9.0 cm). Larger tumors were associated with decreased overall survival (P = .016). Higher grade tumors had decreased overall survival (P = .01). Clear surgical margins were obtained in 67% of patients. Clear surgical margins correlated with improved survival (P = .002). Maxillary JOS constituted 83% of those with positive margins. Overall, 5-year survival was 68%. Improved 5-year survival was noted in group 2 (77%) compared with group 1 (52%) [P = .0073]. Patients who developed secondary osteosarcomas (n = 10) had 4.5-fold increased risk of death (P = .01). Recurrence was associated with 7-fold increased risk of death (P = .0008). Thirteen patients died of JOS., Conclusions: Improved survival was noted in treatment group 2. This group benefited from improved imaging, earlier diagnosis and more aggressive treatment that included improved surgical clearance. A clear survival advantage for neoadjuvant chemotherapy was not demonstrated., (Copyright © 2011 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Purpose: To identify risk factors associated with postoperative inflammatory complications (POICs) after treatment of mandibular fractures., Patients and Methods: The investigators designed a case-control study and enrolled a sample of patients treated for mandibular fractures at Massachusetts General Hospital between August 2004 and January 2010. Subjects who developed POICs after fracture management were categorized as cases. A POIC was defined as 1) recurrent swelling, fever, increased pain, or trismus; 2) wound dehiscence with purulent drainage; 3) exposed or infected hardware; 4) abscess formation; 5) radiographic evidence of osteomyelitis; and/or 6) presence of a fistula. Controls had no complications. For each case, 2 controls were selected. Predictor variables were categorized into the following sets: demographic, fracture-specific, and perioperative. Bivariate and multiple logistic regression analyses were used to identify factors associated with POICs., Results: During the study interval, 575 subjects with mandible fractures were evaluated and treated. The study sample consisted of 44 cases and 88 controls. In the multiple regression model, an increasing Mandibular Injury Severity Score (odds ratio = 1.4; 95% confidence interval 1.2-1.6) and a positive medical history (odds ratio = 1.4; 95% confidence interval 1.03-1.8) were significantly (P < .05) associated with an increased risk for a POIC., Conclusion: Fracture severity assessed using the Mandibular Injury Severity Score and pre-existing medical problems were associated with increased risk for postoperative inflammatory complications following treatment of mandibular fractures., (Copyright © 2011 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Purpose: To evaluate changes in airway size and shape in patients with obstructive sleep apnea (OSA) after maxillomandibular advancement (MMA) and genial tubercle advancement (GTA)., Materials and Methods: This was a retrospective cohort study, enrolling a sample of adults with polysomnography-confirmed OSA who underwent MMA + GTA. All subjects who had preoperative and postoperative 3-dimensional computed tomography (CT) scans to evaluate changes in airway size and shape after MMA + GTA were included. Preoperative and postoperative sleep- and breathing-related symptoms were recorded. Descriptive and bivariate statistics were computed. For all analyses, P < .05 was considered statistically significant., Results: During the study period, 13 patients underwent MMA + GTA, of whom 11 (84.6%) met the inclusion criteria. There were 9 men and 2 women with a mean age of 39 years. The mean body mass index was 26.3; mean respiratory disturbance index (RDI), 48.8; and mean lowest oxygen saturation, 80.5%. After MMA + GTA, there were significant increases in lateral and anteroposterior airway diameters (P < .01), volume (P = .02), surface area (P < .01), and cross-sectional areas at multiple sites (P < .04). Airway length decreased (P < .01) and airway shape (P = .04) became more uniform. The mean change in RDI was -60%., Conclusions: Results of this preliminary study indicate that MMA + GTA appears to produce significant changes in airway size and shape that correlate with a decrease in RDI., (Copyright © 2011 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Obstructive sleep apnea (OSA) is a disorder characterized by repetitive, episodic collapse of the pharyngeal airway. Over the last two decades, understanding of the pathophysiology of sleep disordered breathing, which includes OSA, has improved. Once thought to be predominately related to anatomic constriction of the maxillomandibular complex, central nervous system regulation of breathing is now recognized as a significant contributor to the pathogenesis of OSA. Ventilator control, the central response to chemoreceptor phenomena, has important implications for oral and maxillofacial surgeons who treat OSA, particularly for patients who appear refractory to treatment with maxillomandibular advancement (MMA). The purpose of this article is to review the biomechanics of the upper airway as it relates to the pathophysiology of OSA, to discuss emerging concepts of ventilator control mechanisms in normal sleep versus sleep-disordered breathing and to discuss the concept of complex sleep apnea, a new category of sleep disordered breathing with both obstructive and central features., (Copyright © 2010 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

Purpose: The purpose of this study was to measure upper airway length (UAL) on lateral cephalograms and to assess its relationship with the presence and severity of obstructive sleep apnea (OSA)., Materials and Methods: Using a case-control study design, the investigators enrolled a sample of cases defined as adult subjects with OSA and controls who were adult patients with skeletal Class II malocclusions. The primary predictor variable was UAL. Other variables were demographic and cephalometric parameters. The respiratory disturbance index (RDI) was used to measure disease severity in cases. Bivariate analyses were computed to evaluate the associations between predictor and outcome variables. Multiple regression analyses were used to provide adjusted measures of association, controlling for the effects of confounders/effect modifiers. Diagnostic test characteristics were computed for threshold airway lengths. P ≤ .05 was considered statistically significant., Results: The sample consisted of 96 cases with OSA (76 males) and 56 controls without OSA (36 males). OSA subjects were older, were predominately male, and had higher body mass indexes and longer and narrower airways (P < .05). After controlling for confounding variables, UALs ≥ 72 mm for males and ≥ 62 mm for females were significantly associated with the presence of OSA (P = .03). The sensitivity and specificity of UAL as a diagnostic test for OSA were ≥ 0.8. UAL was strongly correlated with RDI (disease severity) in males (r = 0.72, P < .01) and moderately correlated with RDI in females (r = 0.52, P < .01)., Conclusion: Increased upper airway length was correlated with the presence and severity of OSA in this sample of adult patients., (Copyright © 2010 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Purpose: To establish a porcine model for maxillary distraction osteogenesis and to document the sequence of bone formation in the zone of advancement., Materials and Methods: Female Yucatan minipigs (n = 9) in the mixed dentition stage underwent modified Le Fort I osteotomy through a vestibular incision under general anesthesia. A unidirectional, semiburied Le Fort I distraction device was fixed across the osteotomy. The distraction protocol was 0-day latency, 1-mm/d rate for 12 days, and 24 days of fixation. Maxillary specimens (n = 9) were harvested and divided in half at the end of distraction (n = 6 sides), midfixation (n = 6), and the end of fixation (n = 6). Clinical stability, volume, and radiographic density across the zone of advancement were graded on semiquantitative scales. Specimens were stained with hematoxylin and eosin and examined with light microscopy., Results: Animals tolerated the operation, the distraction and fixation periods. There were no infections and no devices failed. At the end of the distraction period, bone trabeculae were present at the periphery and fibrous tissues, and vessels, preosteoblasts, and osteoblasts were present in the center of the zone of advancement. Islands of chondrocyte-like cells appeared in 1 specimen each at midfixation and the end of fixation. At the end of fixation, clinical stability and radiographic density were graded 3/3 and bone formation was complete across the advancement zone in all specimens., Conclusion: A model for Le Fort I distraction osteogenesis was established. Intramembranous bone formation was the predominant mechanism of healing in the zone of advancement. Latency was not necessary for bone formation in this minipig model., (Copyright © 2010 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Purpose: To analyze the sequence of histomorphometric changes in the regenerate during distraction osteogenesis (DO) of the minipig mandible., Materials and Methods: A total of 16 minipigs underwent unilateral mandibular DO using a protocol of 0-day latency and a 1-mm/day rate for 12 days, and 24 days of fixation. The mandibles were harvested at mid-DO, end-DO, mid-fixation, and end-fixation. An additional 2 minipigs underwent acute lengthening, and 1 sham control was included. Serial gross examinations and plain radiographs were performed before paraffin embedding. The sections were stained with hematoxylin-eosin or hematoxylin/alcian blue/sirius red stain. Histomorphometric analysis was performed to determine the percentage of surface area (PSA) occupied by hematoma, fibrous tissue, cartilage, and bone., Results: All 19 minipigs survived the operation, and 17 survived the observation period; 2 were killed because of infection (mid-DO, n = 1 and end-fixation, n = 1). No device failures occurred. Of the 17 specimens, 4 were at mid-DO, 4 at end-DO, 4 at mid-fixation, and 2 at end-fixation; 2 were in the acute lengthening group, and 1 was the sham control. Hematoma was present only at mid-DO (16.61 +/- 8.07 PSA) and end-DO (1.17 +/- 2.33 PSA). Fibrous tissue decreased from mid-DO (53.12 +/- 8.59 PSA) to end-fixation (25.00 +/- 0.83 PSA). Cartilage was present in end-DO (1.72 +/- 2.71 PSA), mid-fixation (5.82 +/- 6.64 PSA), and acute lengthening (1.43 +/- 0.95 PSA). Bone increased from mid-DO (25.18 +/- 0.99 PSA) to end-fixation (64.89 +/- 0.79 PSA) and occurred earlier in the superior and middle thirds of the wounds. Periosteal bone formation predominated over endosteal bone formation early in distraction., Conclusion: The results of the present study indicate that bone formation in this model consists of both intramembranous and endochondral components, with intramembranous osteogenesis predominating. Bone formation occurred earlier in the superior/middle portions of the wound, possibly owing to osteoinductive properties of developing tooth buds and the inferior alveolar nerve, respectively., (Copyright 2010 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Purpose: Planar scintigraphy using (99m)Tc-labeled methylene diphosphonate ((99m)Tc-MDP) has been established as a method for evaluating mandibular growth and asymmetry. However, (99m)Tc-MDP single photon emission computed tomography (SPECT) provides improved image contrast and quantitative capability potentially allowing the clinician to make a more accurate assessment of the stage of activity of normal and asymmetric mandibular growth. The purpose of this study was to utilize (99m)Tc-MDP SPECT in normal subjects to develop a standardized approach to imaging the mandible that could subsequently be used to evaluate patients with potential for mandibular growth abnormalities., Methods: Thirty-two patients (22 females, 10 males, 8-25 years of age, mean of 14 years) having (99m)Tc-MDP bone scans (7.4 MBq/kg, maximum of 518 MBq) for indications not involving the head were asked to have an additional SPECT that included the mandibular condyles. Internal (clivus) and external (source of known activity included within the field of view) standards were both investigated. Two- and three-dimensional (2-D and 3-D) regions of interest (ROI) were drawn over each condyle and the clivus in a single slice containing the maximum pixel value within the structure. A 3-D ROI was also drawn about the external standard. Maximum and average pixel values within the 2-D and 3-D ROIs were recorded., Results: Correlation analysis indicated that essentially the same information was obtained whether the maximum or average pixel value within a 2-D or 3-D ROI was used. The right to left ratio provided a parameter that can be used to assess the magnitude of mandibular metabolic asymmetry. Use of an external standard provides the potential for quantifying condylar uptake for assessment of the activity of mandibular growth. Normal ranges for different age groups were determined for condylar uptake using both internal and external standards., Conclusion: (99m)Tc-MDP SPECT provides a quantitative method for assessing mandibular condylar uptake as a reflection of the activity of mandibular growth. The maximum pixel value of a 2-D ROI using external standardization and the right to left ratio of the condylar uptake provide the potential for quantitative evaluation of patients with mandibular asymmetry. These parameters will be further evaluated in an upcoming clinical investigation.

Distraction osteogenesis to expand the facial skeleton is an alternative to standard orthognathic surgery for selected patients with obstructive sleep apnea. For children with congenital micrognathia or midface hypoplasia, distraction osteogenesis allows large advancements without the need for bone grafting and with less risk of relapse. For later-onset obstructive sleep apnea, distraction osteogenesis may represent an alternative when acute bone movement is expected to be difficult (scarring from previous surgery or radiation therapy) or when the risk for inferior alveolar nerve damage is unacceptable (patients older than 40 years).

Temporomandibular joint (TMJ) ankylosis in children is a challenging problem. Surgical correction is technically difficult and the incidence of recurrence after treatment is high. The purpose of the present report is to describe the protocol currently used at the Massachusetts General Hospital for the management of TMJ ankylosis in children. It has been our observation that the most common cause of treatment failure is inadequate resection of the ankylotic mass and failure to achieve adequate passive maximal opening in the operating room. The 7-step protocol consists of 1) aggressive excision of the fibrous and/or bony ankylotic mass, 2) coronoidectomy on the affected side, 3) coronoidectomy on the contralateral side, if steps 1 and 2 do not result in a maximal incisal opening greater than 35 mm or to the point of dislocation of the unaffected TMJ, 4) lining of the TMJ with a temporalis myofascial flap or the native disc, if it can be salvaged, 5) reconstruction of the ramus condyle unit with either distraction osteogenesis or costochondral graft and rigid fixation, and 6) early mobilization of the jaw. If distraction osteogenesis is used to reconstruct the ramus condyle unit, mobilization begins the day of the operation. In patients who undergo costochondral graft reconstruction, mobilization begins after 10 days of maxillomandibular fixation. Finally (step 7), all patients receive aggressive physiotherapy. A case series of children with ankylosis treated using this protocol is presented.

Purpose: To evaluate the staining density of CD34, a glycoprotein expressed in hematopoetic precursor and capillary endothelial cells, as a molecular marker for predicting clinical behavior of giant cell tumors., Materials and Methods: This was a retrospective study of patients with giant cell lesions of the jaws treated over a 15-year period. The primary predictor variable was mean CD34 staining density. The outcome measure was giant cell tumor clinical behavior (aggressive vs nonaggressive). Bivariate analyses were computed to evaluate the association between the predictors and outcome. A receiver-operator characteristic (ROC) curve was used to establish the threshold for a positive diagnostic test. A logistic regression model was used to evaluate the association between the clinical behavior and a positive test. A value of P

Purpose: To report the use of a semiburied curvilinear distraction device, with a 3-dimensional (3D) computed tomography treatment planning system, for correction of mandibular deformities., Materials and Methods: This was a retrospective evaluation of 13 consecutive patients, with syndromic and nonsyndromic micrognathia, who underwent correction by curvilinear distraction osteogenesis. A 3D computed tomography scan was obtained for each patient and imported into a 3D treatment planning system (Slicer/Osteoplan). Surgical guides were constructed to localize the osteotomy and to drill holes to secure the distractor's proximal and distal footplates to the mandible. Postoperatively, patients were followed by clinical examination and plain radiographs to ensure the desired vector of movement. At end distraction, when possible, a 3D computed tomography scan was obtained to document the final mandibular position., Results: Of the 13 patients, 8 were females and 5 were males, with a mean age of 11.9 years (range 15 months to 39 years). All 13 underwent bilateral mandibular curvilinear distraction. Of the 13 patients, 8 were 16 years old or younger and 5 were younger than 6 years of age. The diagnoses included Treacher Collins syndrome (n = 3), Nager syndrome (n = 3), craniofacial microsomia (n = 2), post-traumatic ankylosis (n = 1), and micrognathia (syndromic, n = 3; nonsyndromic, n = 1). The correct distractor placement, vector of movement, and final mandibular position were achieved in 10 of 13 patients. In the other 3 patients, the desired jaw position was achieved by "molding" the regenerate., Conclusions: The use of a semiburied curvilinear distraction device, with 3D treatment planning, is a potentially powerful tool to correct complex mandibular deformities.

This paper represents more than 30 years of discussion and collaboration with Drs Joseph Murray and John Mulliken in an attempt to understand growth patterns over time (ie, fourth dimension) in patients with hemifacial microsomia (HFM). This is essential for the development of rational treatment protocols for children and adults with jaw asymmetry. Traditionally, HFM was thought of as a unilateral deformity, but it was recognized that 20% to 30% of patients had bilateral abnormalities. However, early descriptions of skeletal correction addressed almost exclusively lengthening of the short (affected) side of the face. Based on longitudinal clinical observations of unoperated HFM patients, we hypothesized that abnormal mandibular growth is the earliest skeletal manifestation and that restricted growth of the mandible plays a pivotal role in progressive distortion of both the ipsilateral and contralateral facial skeleton. This hypothesis explains the progressive nature of the asymmetry in patients with HFM and provides the rationale for surgical lengthening of the mandible in children to prevent end-stage deformity. During the past 30 years, we have learned that this phenomenon of progressive distortion of the adjacent and contralateral facial skeleton occurs with other asymmetric mandibular undergrowth (tumor resection, radiation therapy, or posttraumatic defects) and overgrowth (mandibular condylar hyperplasia) conditions. In this paper, I describe the progression of deformity with time in patients with mandibular asymmetry as a result of undergrowth and overgrowth. Understanding these concepts is critical for the development of rational treatment protocols for adults with end-stage asymmetry and for children to minimize secondary deformity.

BACKGROUND: Distraction osteogenesis (DO) is a technique of bone lengthening that makes use of the body's natural healing capacity. An osteotomy is created and a rigid distraction device is attached to the bone. After a latency period, the device is activated 2-4 times per day for a total of 1 mm/day of bone lengthening. This technique is used to correct a variety of congenital and acquired deformities of the mandible, midface and long bones. To shorten the treatment period and to eliminate the complications of patient activation of the device, an automated continuous distraction device would be desirable. It has been reported that continuous distraction generates adequate bone with lengthening at a rate of 2 mm/day, thereby reducing the treatment time. METHOD OF APPROACH: The device we describe here uses miniature high-pressure hydraulics, position feedback, and a digital controller to achieve closed-loop control of the distraction process. The implanted actuator can produce up to 40N of distraction force on linear trajectories as well as curved distraction paths. In the paper we detail the spring-powered hydraulic reservoir, controller, and user interface. RESULTS: Experiments to test the new device design were performed in a porcine cadaver head and in live pigs. In the cadaver head, the device performed an 11-day/11 mm distraction with a root-mean-squared position error of 0.09 mm. The device functioned for periods of several days in each of five live animals, though some component failures occurred, leading to design revisions. CONCLUSIONS: The test series showed that the novel design of this system provides the capabilities necessary to automate distraction of the mandible. Further developments will focus on making the implanted position sensor more robust and then carrying out clinical trials.

Purpose: Current strategies for jaw reconstruction require multiple operations to replace bone and teeth. To improve on these methods, we investigated simultaneous mandibular and tooth reconstruction, using a Yucatan minipig model., Materials and Methods: Tooth and bone constructs were prepared from third molar tooth tissue and iliac-crest bone marrow-derived osteoblasts isolated from, and implanted back into, the same pig as an autologous reconstruction. Implants were harvested after 12 and 20 weeks and evaluated by x-ray, ultrahigh-resolution volume computed tomographic (VCT), histological, and immunohistochemical analyses., Results: Small tooth structures were identified, and consisted of organized dentin, enamel, pulp, and periodontal ligament tissues, surrounded by new bone. No dental tissues formed in implants without tooth-bud cells, and bone regeneration was observed to a limited extent. Immunohistochemical analyses using tooth-specific and bone-specific antibodies confirmed the identity of regenerated tissues., Conclusions: This pilot study supports the feasibility of tissue-engineering approaches for coordinated autologous tooth and mandible reconstruction, and provides a basis for future improvement of this technique for eventual clinical use in humans.

Proper rehabilitation of craniofacial defects is challenging because of the complexity of the anatomy and the component tissue types. The ability to simultaneously coordinate the regeneration of multiple tissues would make reconstruction more efficient and might reduce morbidity and improve outcomes. The craniofacial complex is unique because of the presence of teeth, in addition to skin, bone, cartilage, muscle, vascular, and neural tissues since teeth naturally grow in coordination with the craniofacial skeleton, our group developed an autologous, tooth-bone hybrid model to facilitate repair of mandibular defects in the Yucatan minipig. The hybrid tooth-bone construct was prepared by combining tooth bud cell-seeded scaffolds with autologous iliac crest bone marrow derived stem cell-seeded scaffolds, which were transplanted back into surgically created mandibular defects in the same minipig. The constructs were harvested after 12 and 20 weeks of growth. The resulting bone/tooth constructs were evaluated by X-ray, ultra high-resolution volume computed tomography (VCT), histological, immunohistochemical analyses, and transmission electron microscopy (TEM). The observed formation of small tooth-like structures consisting of organized dentin, enamel, pulp, cementum, periodontal ligament, and surrounded by regenerated alveolar bone, suggests the feasibility for regeneration of teeth and associated alveolar bone, in a single procedure. This model provides an accessible method for future clinical applications in humans.

Minimally invasive surgery is defined as the discipline in which operative procedures are performed in novel ways to diminish the sequelae of standard surgical dissections. The goals of minimally invasive surgery are to reduce tissue trauma and to minimize bleeding, edema, and injury, thereby improving the rate and quality of healing. In orthognathic surgery, there are two minimally invasive techniques that can be used separately or in combination: (1) endoscopic exposure and (2) distraction osteogenesis. This article describes the historical developments of the fields of orthognathic surgery and minimally invasive surgery, as well as the integration of the two disciplines. Indications, techniques, and the most current outcome data for specific minimally invasive orthognathic surgical procedures are presented.

Purpose: A cant of the maxillary intermolar (M1-M1) plane is a reflection of facial asymmetry and can be measured on an anterior-posterior cephalogram in degrees relative to the true horizontal or directly on the patient as the difference in millimeters between the right and left medial canthi to canine distances. The purpose of this study is to measure the correlation between the maxillary cant measured in degrees and measured in millimeters., Materials and Methods: We hypothesize that the number of degrees of maxillary cant equals the millimeter difference between the lengths of the 2 sides of the maxilla, based upon the trigonometric relationship between the degree of cant, vertical length, and M1-M1 distance. To confirm this hypothesis, we evaluated a range of M1-M1 distances and computed the predicted vertical discrepancy between the 2 sides of the maxilla. Bivariate correlations were used to evaluate the association between the degree of cant and predicted vertical discrepancy., Results: In the range of M1-M1 distances (47.5-61.1 mm) evaluated, cants ranging from 3 to 10 degrees are highly correlated with the vertical difference in millimeters (r = 0.96, P < .01). The mean error between the degree of cant and vertical difference was 9%., Conclusion: The degrees of occlusal cant relative to the true horizontal measured cephalometrically in the frontal plane is equal to the linear millimeter difference between the right and left medial canthi to the right and left canine tips.

Background: Although vascularized bone grafts have become well accepted in adults, especially following ablative head and neck procedures, there are few long-term reports of their use in pediatric patients., Methods: In this study, the authors analyzed the outcomes of 18 free fibula grafts in 16 patients aged 10 months to 21 years (mean, 12 years) with an average follow-up of 5 years. Eleven patients had cancer-related defects, four had craniofacial anomalies, and one had a posttraumatic deformity. All patients with congenital malformations had been followed since birth, and the others had been followed from the time of their original cancer diagnosis or injury., Results: Of the 16 patients, seven underwent irradiation and seven underwent chemotherapy. The most severe deformities were seen in those with cancer resection and radiation therapy. Most defects were hemimandibular; there was one total mandibular defect (a child with Ewing sarcoma). Ten patients had had previous failed nonvascularized bone grafts. Eleven flaps were osteocutaneous with either intraoral or extraoral components; most had multisegmental osteotomy and had one arterial and two venous anastomoses. All free fibula transfers were successful; there were no vascular problems and only two minor complications., Conclusion: A number of lessons are learned from careful analysis of this unique group of patients, and an algorithm of pediatric mandibular reconstruction is proposed.

Purpose: To compare CD34 expression in both aggressive and nonaggressive giant cell lesions of the jaws and identify any associations between tumor vascular density and biologic behavior., Materials and Methods: This was a retrospective study of subjects treated for giant cell lesions of the jaws at Massachusetts General Hospital from 1992 to 2006. The primary predictor variable was tumor classification (aggressive or nonaggressive); tumors were considered aggressive if they were greater than 5 cm in size, recurred after treatment, or exhibited 3 of the following: presence of root resorption, tooth displacement, or cortical bone thinning or perforation. Secondary predictor variables, recorded for each patient, were demographic, anatomic, and clinical measures. The outcome variable was the average CD34 staining density of histologic specimens quantified in 2 different areas. Descriptive and bivariate statistics were computed to identify predictors associated with vascular density., Results: The study sample was composed of 32 subjects with a mean age of 24.4 +/- 19.77 years (range: 2-83); 23 subjects (71.8%) were female. Of the tumors included, 11 (34.4%) were located in the maxilla, 21 (65.6%) in the mandible. Twenty-six tumors (81.2%) were classified as aggressive; the remainder (18.8%) were nonaggressive. There were no statistically significant differences between subjects with aggressive versus nonaggressive tumors with regard to age, gender, or location. Subjects with aggressive tumors had a significantly higher CD34 staining density (P = .02). None of the secondary predictors was associated with vascular density., Conclusion: Vascular density of giant cell tumors of the jaws is significantly increased in aggressive tumors.

Purpose: Sialoendoscopy is a novel minimally invasive technique to explore the salivary duct system and to treat obstructive salivary disease. This article describes the early clinical experience with endoscopic salivary duct exploration and sialolithectomy in 2 medical centers., Patients and Methods: This is a retrospective case series of 94 patients, with submandibular (n = 77) or parotid (n = 17) sialadenitis secondary to sialolithiasis, strictures, or mucous plugs. Patients underwent sialoendoscopy at Baptist Hospital, Miami (n = 52) or at Massachusetts General Hospital, Boston (n = 42). Dilatation of the duct through the natural orifice was accomplished with salivary dilators. Three endoscope systems with diameters from 1.1 to 2.3 mm were used. Using a basket, grasper, lithotripsy, laser, or a combination of these, stones were fragmented or removed endoscopically. Strictures were dilated and mucous plugs removed. All cases were carried out under general anesthesia., Results: Salivary duct navigation was accomplished in 91/94 patients. In 3 cases, duct dilatation was not possible due to scarring. Symptomatic relief was achieved in 81/91 patients (89.4%). Strictures and mucous plugs were visualized and managed in 18/18 patients. Sialoliths were visualized in 73 patients and stone fragmentation or retrieval was accomplished in 84.93% (62/73) of cases. Complications included 2 patients with temporary lingual nerve paresthesia and 1 patient with excess extravasation of irrigation fluid., Conclusion: The results of this study indicate that interventional sialoendoscopy is an effective, minimally invasive alternative treatment for obstructive salivary gland disease.

Purpose: The purpose of this study was to estimate the hospital length of stay (LOS) and identify factors associated with LOS in orthognathic surgery patients., Materials and Methods: Using a retrospective cohort study design, we enrolled a sample composed of patients who underwent orthognathic surgery at Massachusetts General Hospital between January 1994 and July 2006. The primary predictor variables were fixation type (rigid/nonrigid), anesthesia technique (hypotensive/normotensive), and perioperative steroid use (yes/no). The outcome variable was LOS. Descriptive statistics were computed for all variables. Bivariate analyses were used to identify factors associated with duration of LOS with P values less than .15. Multiple regression modeling was used to assess the relationship between the primary predictor variables and LOS. The level of statistical significance was set at P less than .05., Results: The study sample was comprised of 627 subjects (58.5% female) with a mean age of 26.1 +/- 10.2 years. The overall mean LOS was 1.7 +/- 1.2 days. During the study period, LOS decreased from 2.3 to 1.3 days (P < .001). In the adjusted multiple regression model, rigid fixation, procedure type, and length of operation were statistically significantly associated with LOS (P < .05)., Conclusion: The results of this study indicate that individual variables associated with duration of LOS are complexity of the orthognathic procedure and type of fixation used. In the multiple logistic regression model, LOS decreases significantly when rigid fixation, hypotensive anesthesia, and perioperative steroids are used in combination.

Distraction osteogenesis (DO) has gained clinical acceptance as a surgical technique for treatment of congenital craniomaxillofacial deficiencies requiring skeletal expansion. The use of this technique elsewhere requires more information on overcoming difficult clinical settings, for which new animal models will be needed. The aim of this study was to develop and validate a model of impaired DO of the rat mandible with nicotine. Twenty rats underwent a right vertical mandibular body osteotomy, after which distraction began with custom-made percutaneous devices and a 3-day latency period, 6-day distraction (0.25 mm twice daily) and 30 days of neutral fixation. Rats received either nicotine or placebo slow-release pellets. Specimens were analysed after removal of the devices for quantitative radiographic bone fill, amount of bone advancement and histological features. The mean radiographic bone-fill score with nicotine treatment was 75% of that with placebo (P=0.0036). The nicotine-treated rats had less (49%) elongation than the placebo-treated controls (P=0.0008). Histological analysis demonstrated less bone, vascularity and cellular activity in nicotine-treated rats. This study shows that nicotine reproducibly inhibits osteogenesis, vascularity and bone lengthening in mandibular DO.

The desmoplastic variant of ameloblastoma is a rare, locally invasive, benign tumor of the jaws, typically found in the anterior regions of the maxilla and mandible. This ameloblastoma variant has been described as an intraosseous tumor; to our knowledge, there have been no published cases of a peripheral desmoplastic ameloblastoma. The purpose of this case report is to describe a patient with a desmoplastic ameloblastoma localized to the soft tissue of the palate with no osseous involvement.

Purpose: The purpose of this study was to evaluate the outcomes in patients with active bilateral idiopathic condylar resorption treated by condylectomy and costochondral graft (CCG) reconstruction., Patients and Methods: This was a retrospective evaluation of 15 consecutive patients treated at Massachusetts General Hospital from 1999 to 2004 who had: 1) active bilateral idiopathic condylar resorption confirmed by clinical examination, plain radiographs, and technetium-99 bone scan; 2) adequate documentation; and 3) a minimum of 12 months follow-up. Patients with an identifiable cause of condylar resorption such as rheumatoid or degenerative arthritis, trauma, or steroid use, or who had less than 12 months follow-up were excluded. Preoperative, immediate postoperative, 6-month, 12-month, and latest follow-up clinical examinations, lateral cephalograms, and panoramic radiographs were used to evaluate the outcomes. Inferior alveolar and marginal mandibular nerve function, jaw motion, and occlusion were evaluated by history and physical examination. All patients underwent bilateral condylectomy and CCG reconstruction., Results: There were 13 female and 2 male patients with a mean age of 24 years. Mean follow-up was 34 months (range, 12 to 84). Preoperatively, all patients had Class II malocclusion: mean overjet 6.2 mm and mean anterior open bite -2.65 mm. At latest postoperative follow-up, all patients showed Class I occlusion with no anterior open bite, a stable and reproducible occlusion, and a normal range of TMJ motion with a mean maximal incisal opening of 39 mm., Conclusion: The results of this study indicate that a stable and satisfactory outcome is achievable in patients with active idiopathic condylar resorption treated by condylectomy and CCG reconstruction.

Purpose: Osteoradionecrosis (ORN) of the jaws has been extensively studied. However, controversy still exists regarding its etiology, risk factors, and the underlying mechanism of disease. The purpose of this study was to identify and evaluate significant risk factors for the development of ORN., Patients and Methods: This was a retrospective cohort study of 82 Massachusetts General Hospital patients radiated for head and neck cancer between 1984 and 2005. Patient records were reviewed to collect demographic information, medical and dental history (including dental intervention or trauma), tumor specific data, treatment details, and follow-up. Biologic variables (ie, age and gender) of potential significance were also evaluated. The major outcome variable was the development of ORN or lack of development of ORN. The time from radiation to ORN, or for non-ORN patients, time to last follow-up visit, was computed. Univariate analyses identified candidate variables associated with ORN (P < .15). Cox proportional hazards regression was used to evaluate these candidate variables as well as biologically relevant variables. Significant prognostic factors for the development of ORN (P < .05) were identified., Results: Multivariate regression identified the following variables as significantly associated with decreased ORN risk: higher body mass index (P = .02) and use of steroids (P = .02). Radiation dose greater than 66 Gray (P = .03) was associated with an increased ORN risk., Conclusions: Optimization of nutritional status, use of steroids, and limitation of total radiation dose may minimize the risk of ORN.

Purpose: The purpose of this study was to assess the effectiveness of ultrasonography in visualizing the lingual nerve, calculating its distance from the lingual cortex at the area of the third molar, and in detecting injuries., Materials and Methods: Using a standardized protocol, lingual nerve dissections were performed in Yorkshire pig cadaver heads. After nerve isolation was confirmed, the nerve was left intact, fully transected, or partially transected. The dissection flap was repositioned and the pig heads were given to 3 blinded evaluators. Using a handheld ultrasound device, the evaluators were asked to determine the status of the nerve and categorize their finding as intact, fully transected, or partially transected. The recorded ultrasound images from the 9 study specimens were then analyzed and the distances of the lingual nerves from the alveolus were measured., Results: After becoming familiar with the ultrasonographic appearance of the lingual nerve, all of the evaluators were able to visualize and identify the nerve using the ultrasound machine. Lingual nerve injuries were accurately categorized in 17 out of the 27 total attempts (success rate, 63%). The average distance of the nerve from the alveolar cortex was measured to be an average distance of 1 mm., Conclusion: The results of this study indicate that ultrasonography can be effectively used to visualize the lingual nerve.

Objective: To determine the proportion of hemifacial microsomia (HFM) in patients with unilateral or bilateral "isolated" microtia., Design: Prospective cohort clinical study., Setting: University-affiliated, tertiary referral clinic for patients with microtia., Patients: One hundred consecutive patients with isolated microtia., Interventions: All the patients underwent a clinical examination and audiologic evaluation. The OMENS classification system was used to grade the severity of craniofacial features: orbital deformity, mandibular hypoplasia, ear deformity, nerve (cranial nerve VII) involvement, and soft-tissue deficiency. Each anatomical abnormality was graded from 0 (normal) to 3 (most severe) (score range, 0-15)., Main Outcome Measures: The OMENS scores, percentage of patients with isolated microtia and undiagnosed HFM, and isolated microtia as an early clinical marker for HFM., Results: Forty patients (40%) with microtia were determined to have HFM (31 unilateral and 9 bilateral). Mean patient age was 9.2 years (range, 6 weeks to 41 years), with male predominance (27 males and 13 females). The OMENS scores were less than 5 in 24 patients and 6 to 10 in 16 patients. Thirty patients had cranial nerve deficits, and 37 had mandibular asymmetry. Thirty-seven patients demonstrated conductive hearing loss, and 1 had sensorineural hearing loss., Conclusions: Isolated microtia served as an early clinical marker for asymmetrical facial growth in 40% of the patients. Isolated microtia and HFM could represent a spectrum of expression of the same developmental phenomenon.