Alveolar ridge repair in a canine model using rhTGF-beta 1 with barrier membranes.

In both normal and membrane-assisted situations, healing events are modulated by the activity of endogenous protein molecules known as cytokines. Due to its mitogenic and chemotactic characteristics, the addition of rhTGF-beta 1 should increase the rate of osteogenesis or increase the potential for bone regeneration in oral osseous defects. This study evaluates the effects of an osteoconductive biodegradable matrix incorporating human recombinant transforming growth factor beta 1 (rhTGF-beta 1) in conjunction with barrier membranes on bone regeneration in canine alveolar ridge defects. A matrix of calcium carbonate and hydroxyethyl starch served as the carrier for test concentrations of 2.0 micrograms/0.8 ml and 20.0 micrograms/0.8 ml of rhTGF-beta 1. One surgically prepared site in each of 13 adult male fox-hounds received 1 of 4 experimental treatment regimens, with 6 sites utilizing barrier membranes. Four sites in each of 2 additional animals, two containing carrier matrix only and 2 with the additional barrier membrane, served as controls. Specimens were retrieved after 2 months of healing and processed for routine light microscopy. The quantity and composition of regenerated bone was examined. Analysis of variance revealed a statistically significant increase (P < 0.05) in the development of bone with the use of rhTGF-beta 1. Likewise, a statistically significant increase in regeneration was found in membrane-protected sites over nonmembrane-protected sites. No statistically significant difference was noted between the low and high dose treatments. The authors conclude that the use of rhTGF-beta 1 in conjunction with a barrier membrane greatly enhances bone regeneration in osseous oral defects.

Photoelastic analysis of miniplate osteosynthesis for mandibular angle fractures.

OBJECTIVE: The purpose of this study was to reassess Champy's findings, which were instrumental in justifying the theory of tension band plating for mandibular angle fractures. STUDY DESIGN: Ten anatomically correct mandibles were fabricated with a photoelastic resin. In five mandibles, angle fractures were created and fixed with a superior border miniplate; five uncut mandibles served as controls. Each mandible was loaded in a manner that simulated physiologic conditions. The internal stress patterns were preserved within the models by completing a stress freezing cycle. RESULTS: The stress patterns in the experimental mandibles virtually replicated the patterns seen in the controls. Stress fringes were present surrounding the outer screws, indicating that these screws were subjected to pull-out forces. CONCLUSIONS: There is greater force on the outer screws that may contribute to fixation failure. The theory of tension band plating for mandibular angle fractures is accurate but Champy's model is oversimplified.

The relation of radiosensitivity of hypopharyngeal squamous cell carcinoma to DNA ploidy.

PURPOSE: The purpose of this study was to examine the radiosensitivity of T1, N0, M0 squamous cell carcinomas of the hypopharynx treated solely with external beam radiation. MATERIALS AND METHODS: Nuclear DNA content and cell cycle kinetics of 29 archival paraffin-embedded specimens suitable for interpretation were analyzed with an ELITE flow cytometer (Coulter Diagnostics, Opa Locka, FL). RESULTS: In the radiosensitive group with no evidence of disease for 36 months, 86% of the tumors were diploid and 14% were aneuploid. The mean DNA index for this group was 1.02. In the radioresistant group, with recurrence within 36 months, 80% of the tumors were aneuploid, and 20% were diploid. The mean DNA index for this group was 1.32. CONCLUSIONS: The findings could have clinical significance because if aneuploidy occurs in an early hypopharyngeal squamous cell carcinoma, the clinician might select surgical resection over radiation therapy.

Surgical approaches to repositioning of the inferior alveolar nerve for placement of osseointegrated implants.

Severe resorption of the posterior mandible poses one of the most difficult restorative challenges to the implant surgeon today. Although bone augmentation procedures may increase the amount of bone in which to place implants, these procedures are costly and have an increased risk of complications to the patient. With the proper evaluation, treatment planning, and attention to technical detail, nerve repositioning appears to offer an excellent alternative to augmentation procedures for placement of dental implants.

Flow cytometric analysis of squamous cell carcinoma of the tongue.

The purpose of this study was to examine the relationship between anatomic location and the cytogenetic and cytokinetic characteristics of squamous cell carcinoma of the tongue to determine the diagnostic and prognostic potential of flow cytometry. Fifty-two archival, paraffin-embedded specimens of squamous cell carcinoma of the tongue in clinical stages I-IV acquired from 1975 to the present were analyzed with an ELITE flow cytometer (Coulter Diagnostics, Opa Locka, FL). Histopathologic grading was performed by the same pathologist based on tumor differentiation. Of the 40 specimens found suitable for analysis, several correlations were noted. First, as the clinical stage increased, the % S-phase increased. Second, there was no correlation between the histologic grade and the % S-phase. Finally, the % S-phase was higher in those tumors with nodal involvement.

Recurrent enlargement of the left maxillary alveolus.

Presented is a case report of osteosarcoma of the maxilla in a patient with Paget's disease. This case is unusual because of recurrent benign soft tissue enlargements at the site of eventual malignant disease.

Flow cytometric analysis of posterior oropharyngeal tumors.

To date, few studies have evaluated the diagnostic and prognostic potential of flow cytometry in oropharyngeal tumors. The purpose of this study was to evaluate the interrelationship of anatomic location with the cytogenetic and cytokinetic characteristics of squamous cell carcinomas of the posterior oropharynx. Forty-eight paraffin-embedded squamous cell carcinoma specimens from the posterior oropharynx in clinical stages I to IV were analyzed with an Epics-C flow cytometer (Coulter Diagnostics, Hialeah, FL). Histopathologic grading was performed by the same pathologist, based on tumor differentiation. Of the 38 specimens suitable for analysis, several correlations were noted. First, as the %S-phase increased, the clinical stage increased. Second, as the histologic grade increased, the aneuploid frequency increased. Finally, as the tumor size increased, the histologic grade increased. From the results of this study, it was concluded that %S-phase may be useful in assessing the prognosis of squamous cell carcinomas of the posterior oropharynx. DNA index or aneuploid frequency, also may have value as a prognostic indicator. Finally, the lack of correlation between TNM staging and histologic grading stems not from tumor size but from nodal and metastatic involvement. Further studies are warranted to better define the usefulness of flow cytometric analysis in squamous cell carcinomas of the oropharyngeal region.

Treatment of mammalian bite wounds of the maxillofacial region.

Infected human bites may result in devastating consequences. Failure to recognize the destructive potential of infections of bone, tendons, joints, and soft tissue caused by oral microorganisms can lead to serious loss of intrinsic functions. Rapid prevention or resolution of infection by appropriate use of antibiotics and surgical treatment continues to be a therapeutic challenge.

Comparative trial of oral clotrimazole and nystatin for oropharyngeal candidiasis prophylaxis in orthotopic liver transplant patients.

A prospective randomized study was conducted to assess the effectiveness of clotrimazole troches and nystatin suspension to prevent oral candidiasis in immunosuppressed orthotopic liver transplant patients. Thirty-four patients received either clotrimazole troches, 10 mg, five times daily, or nystatin suspension, 500,000 units, four times daily. Prophylaxis was initiated after extubation after transplantation and continued throughout the hospitalization. One of 17 patients in each treatment group developed clinical and microscopic evidence of an oropharyngeal Candida infection. This gave an intragroup and an overall infection rate of 5.9%. It appears that either nystatin or clotrimazole may be used for candidiasis prophylaxis in orthotopic liver transplant patients.

Erosive arthritis of the temporomandibular joint caused by Teflon-Proplast implants: plain film features.

Six patients had osseous destructive changes of the temporomandibular joint after placement of Teflon-Proplast implants for treatment of internal derangements. The implants were surgically removed from all six joints, and foreign-body reactions were found to account for the radiographic appearance. The plain film radiographic features included single or multiple osseous erosions of the mandibular condyle in all cases and the temporal bone of the glenoid fossa in two cases. Some erosions were poorly defined, whereas others were well defined, either with or without sclerotic margins. Radiologists must be aware of this possible complication of alloplastic temporomandibular joint implants in order to suggest the diagnosis in the appropriate clinical setting.

Radiography after orthognathic surgery. Part I. Normal appearance.

Osteotomies of the mandible and/or maxilla (orthognathic surgery) are common procedures for correcting facial defects. Radiographs of these patients are routinely obtained, and the radiologist must be aware of the normal postoperative appearance as well as surgical complications that may occur. This article presents the common surgical procedures done (sagittal split, vertical subcondylar, genioplasty mandibular osteotomies; and Le Fort I and mid-palatal split maxillary osteotomies) and the routine appearance of uncomplicated procedures on posteroanterior skull and panoramic radiographs. The metallic immobilization devices and orthodontic appliances are also described.

Radiography after orthognathic surgery. Part II. Surgical complications.

In a retrospective review of the radiographs from 100 patients who had undergone orthognathic surgery, the authors found that 10% of radiographs had evidence of surgical complications. These complications were fractures, temporomandibular joint dislocations, transected tooth roots, retained surgical devices, avascular necrosis, malunion or nonunion of osteotomy fragments, and osteomyelitis. Some of these complications are of little significance, while others require immediate intervention. Opacified maxillary sinuses and lucencies around tooth roots are frequent findings that may be confused with abnormalities; however, they represent postoperative blood in the sinuses and resorption of bone due to stress from orthodontic appliances, respectively.