M. Anthony Pogrel

Vascularized bone flaps versus nonvascularized bone grafts for mandibular reconstruction: an outcome analysis of primary bony union and endosseous implant success.

Functional restoration following resection or traumatic injury to the mandible depends on the reliability of the bony reconstruction to heal primarily and support endosseous implants. Although vascularized bone flaps (VBF) and nonvascularized bone grafts (NVBG) are both widely used to reconstruct the mandible, indications for each remain ill‐defined. The purpose of this study was to compare bone graft/flap healing and success of implant placement in patients reconstructed with VBF versus NVBG.

Assessment of the pharyngeal airway space after mandibular setback surgery

PURPOSE This retrospective study evaluated the change in pharyngeal airway space associated with surgical mandibular setback. PATIENTS AND METHODS Lateral cephalograms of 14 adult patients taken preoperatively, immediately postoperatively, and at long-term follow-up were traced, and the width of the pharyngeal airway space and the pharyngeal airway space area were calculated and compared. RESULTS At long-term follow-up, the mean amount of mandibular setback was 9.7 mm. The mean reduction in the distance from the tongue base to the posterior pharyngeal wall was 4.77 mm (28% decrease). The mean reduction in pharyngeal airway space area was 1.52 cm2, which corresponded to a 12.8% reduction. There was a strong correlation between the amount of mandibular setback and the decrease in pharyngeal airway space area. CONCLUSION Mandibular setback surgery causes a long-term decrease in pharyngeal airway space area. In patients who have other risk factors, for example, overweight, short necks, or large tongues, a mandibular setback procedure could possibly predispose to the development of sleep apnea syndrome.

A substrate-gel assay for hyaluronidase activity

Hyaluronic acid (HA) is a key structural element of the extracellular matrix. Turnover rates of HA are determined in part by hyaluronidases, that are themselves modulated by hyaluronidase inhibitors. A substrate polyacrylamide gel electrophoresis procedure is described here that separates enzyme from inhibitors. The HA is embedded in the gel, and following electrophoretic separation, enzymatic digestion of the HA is allowed to occur. The gel is stained with Alcian blue and can be secondarily stained with Coomassie blue. Enzymatic activities appear as cleared bands on a light blue background, while major proteins appear as dark blue bands. The procedure can be performed in the presence or absence of sodium dodecylsulfate, though levels of hyaluronidase activity decrease when the detergent is used. Hyaluronidases active in the neutral or acid pH range can be detected. This technique will facilitate characterization of hyaluronidases and inhibitors from a wide variety of sources.

Diagnosis and management of condylar resorption.

PURPOSE This article discusses the cause, appropriate diagnostic evaluation, and management of progressive condylar resorption. PATIENTS AND METHODS This retrospective study evaluated 28 adult patients with bilateral progressive condylar resorption. Investigation included serial clinical examination, lateral cephalograms, tomograms, and a technetium isotope bone scan when indicated. Twenty-two patients were managed by either condylectomy and reconstruction with a costochondral graft (n = 5 patients) or orthognathic surgery (n = 18 patients). One patient initially had orthognathic surgery and subsequently underwent condylectomy and costochondral grafting, making a total of 23 procedures on 22 patients. Six patients received no surgical treatment. All patients were observed at least 2 years postoperatively. RESULTS Of the 18 patients who underwent orthognathic surgery, four again demonstrated condylar resorption with recurrence of open bite and retrognathism. Four patients had a stable result, but currently have temporomandibular joint (TMJ) symptoms, whereas 10 patients had a stable result (no change in postoperative occlusion or jaw position) without TMJ symptoms. The five cases receiving condylectomy and costochondral grafting were stable and asymptomatic, with good mandibular function. Analysis of the 18 orthognathic surgery patients showed that relapse occurred in patients having bimaxillary surgery with mandibular advancements greater than 5 mm and with a preoperative posterior ramus height of less than 35 mm. CONCLUSION The management of progressive condylar resorption remains controversial. Orthognathic surgery in this small sample was associated with a complication rate (relapse or TMJ dysfunction) of approximately 45% (8 of 18). In contrast, condylectomy and costochondral grafting appeared to produce stable and functional results. Further long-term outcome studies for patients with condylar resorption are needed to corroborate these results.

Management of mandibular ameloblastoma: The clinical basis for a treatment algorithm

PURPOSE This article discusses the management of intraosseous mandibular ameloblastomas as the basis for a treatment algorithm. PATIENTS AND METHODS The records of 26 consecutive patients referred for management of mandibular ameloblastoma were reviewed. Demographic data, location, number and types of prior surgical treatment, radiographic findings, number of recurrences, and reconstructive methods used were analyzed. RESULTS All patients treated with curettage alone developed recurrence (n = 11). No patients treated with either curettage or resection plus liquid nitrogen cryotherapy developed a recurrence (n = 9). Patients whose radiographs showed large tumors with eggshell-thin bony margins, and who underwent segmental resection with excision of the involved soft tissue also had no recurrences (n = 8). In addition, 2 patients were referred with soft tissue recurrence necessitating resection. Both of these patients underwent multiple resective procedures, including neck dissections and skull base resections. All patients were reconstructed with either primary or secondary bone grafting. Only 3 patients went on to have complete dental reconstruction that included osseointegrated implants. CONCLUSIONS Curettage of ameloblastoma results in unacceptable recurrence rates. Lesions contained within the mandible are adequately treated by curettage or marginal resection combined with cryotherapy. Segmental resection of the mandible with involved soft tissue, including periosteum, produces acceptable results when extraosseous spread has occurred. The first operation affords the best chance for cure. When tumor recurs in soft tissue, extensive surgery is necessary to salvage the patient. Few patients in this series went on to full reconstruction that included osseointegrated implants.

The relationship of the lingual nerve to the mandibular third molar region: An anatomic study

PURPOSE This study evaluated the relationship of the mandibular third molar to the lingual nerve. MATERIALS AND METHODS An anatomic dissection of the lingual nerve in the third molar region was done on 20 cadavers (40 sides). RESULTS The position of the nerve on one side bore no statistical relationship to the position of the nerve on the opposite side. The position of the lingual nerve was variable in both the sagittal and coronal planes. In two specimens the nerve lay superior to the lingual plate and in another the superior surface of the nerve was level with the crest of the lingual plate. CONCLUSION These findings have implications for the avoidance of lingual nerve damage during surgery in the third molar and retromolar region of the mandible.

The use of liquid nitrogen cryotherapy in the management of locally aggressive bone lesions

Cryosurgery has a unique role in the management of locally aggressive osseous lesions. By using a combination of enucleation and cryosurgery to devitalize the surrounding bone, the need for segmental mandibular resection is decreased. This article reviews 37 cases managed successfully in this manner.

Effects of low-energy gallium-aluminum-arsenide laser irradiation on cultured fibroblasts and keratinocytes

To assess whether the gallium‐aluminum‐arsenide low energy laser will increase cell proliferation, cell attachment, or cell migration in cultured fibroblasts and keratinocyte models.

Gore-Tex Tubing as a Conduit for Repair of Lingual and Inferior Alveolar Nerve Continuity Defects: A Preliminary Report

PURPOSE This report describes the results of using a Gore-Tex (Gore Company, Flagstaff, AZ) tube as a conduit for repair of continuity defects in the inferior alveolar or lingual nerves. PATIENTS AND METHODS Seven nerve repairs were performed in five patients (M:F = 1:4) with an age range of 16 to 56 years. The duration from injury to repair ranged from 4 to 30 months. Two inferior alveolar and five lingual nerves were repaired. RESULTS All seven patients had anesthesia by objective testing preoperatively and had a continuity defect at the time of operation. The size of the defects ranged from 2 to 15 mm. Two of the seven patients had some return of sensation, occurring in defects of 3 mm or smaller. CONCLUSION The results of this pilot study indicate that Gore-Tex tubing may not be effective in the repair of continuity defects except in those defects 3 mm or smaller, in which it may act as a protective barrier membrane rather than as a conduit.

Cephalometric norms in Japanese adults

PURPOSE Knowledge of the normal dentofacial patterns of adults belonging to various ethnic and age groups is important for clinical and research purposes. Lateral cephalometric standards of normal Japanese adults were developed using the Burstone and Legan comprehensive cephalometric analyses that are specific for orthognathic surgery. PATIENTS AND METHODS Cephalometric radiographs of 217 Japanese adults were analyzed, and the mean values of their hard and soft tissue measurements were compared with those of white American adults. RESULTS Statistically significant differences were found in the Japanese sample, who had a shorter maxilla, larger upper anterior face height, and lower posterior dental height than Burstones white sample. A less prominent chin was observed in the Japanese male group. Soft tissue analysis of the Japanese subjects showed a retrognathic maxilla and mandible in relation to the soft tissue glabella and bilabial protrusion when compared with the white adult standards. CONCLUSION Lateral cephalometric norms are specific for the racial group, but these values should not be interpreted as treatment goals. Normative data represents an aid for the diagnosis and treatment planning of orthognathic surgery according to the needs and expectations of each individual patient.