Evaluation of the effect of mandibular length and height on the sagittal split ramus osteotomy rigid internal fixation techniques: A finite element analysis.

PURPOSE: A major concern after mandibular advancement with sagittal split ramus osteotomy surgery is postoperative stability and relapse. Currently, there is no consensus on the ideal fixation technique, or how prognosis is affected by mandibular height and length. The aim of the present study was to assess stress distribution on the fixation units and the bone after sagittal split ramus osteotomy and determine the contributions of different mandibular body heights and lengths. MATERIALS AND METHODS: Sagittal split ramus osteotomy and mandibular advancement were simulated in different height/length models prior to fixation using a miniplate, hybrid, or inverted L system using finite element analysis. The greatest and least amount of stress was generated using the miniplate, and inverted L system, respectively. RESULTS: The highest tension and compression in the bone was measured in the miniplate system. While the inverted L system generated less stress in the fixation units than the hybrid system, the hybrid system caused less stress in the bone and lower displacement values compared to other systems. An increase in length, and a decrease in height, both promoted stress, however, the difference was greatest in the former. CONCLUSION: Based on our results, when sagittal split ramus osteotomy is planned for a rather long or thin mandible, using the hybrid system for fixation is recommended.

Recurrence rate of odontogenic keratocyst treated by enucleation and peripheral ostectomy: Retrospective case series with up to 12 years of follow-up.

BACKGROUND: Odontogenic keratocysts have been reported with high recurrence rates in the literature so various treatment modalities from simple enucleation to resection have been performed to achieve the cure. The purpose of this retrospective study was to investigate the recurrence rate of odontogenic keratocysts (OKCs) treated by enucleation and peripheral ostectomy. MATERIAL AND METHODS: An electronic search of the database of the Hacettepe University, Faculty of Medicine, Department of Pathology, was undertaken to identify patients histologically diagnosed with OKCs treated at Department of Oral and Maxillofacial Surgery between 2001 and 2015. RESULTS: In total, 81 patients were studied. The mean age at the time of diagnosis was 42 years, and the male:female ratio was 1:0.7. OKCs were located primarily in the posterior mandibular region (41%). Twenty-seven patients were re-examined to determine the recurrence rate. The mean follow-up period was 5 years (range, 1-12 years). The recurrence rate was 14.8%. The relationship between location of the lesion and recurrence was not statistically significant (p = 0.559). There was also no statistically significant relation between the recurrence rate and treatment option of teeth involved in the lesion (p = 0.579). CONCLUSIONS: The authors conclude that treatment of OKCs by enucleation with peripheral ostectomy is associated with minimal morbidity and is preferred over other aggressive treatment modalities. Meticulous radiographic examination and careful surgical resection may decrease the recurrence rate of OKCs.

Evaluation of hyaluronic matrix efficacy in sinus augmentation: a randomized-controlled histomorphometric and micro-computed tomography analysis.

The objective of the present study was to test the hypothesis that the addition of hyaluronic acid-based matrix to collagenated heterologous bone graft for sinus augmentation would enhance bone formation compared to collagenated heterologous bone graft alone in the early healing period, by micro-computed tomography and histomorphometry. Thirteen systemically healthy patients requiring bilateral two-stage maxillary sinus augmentation (residual crest height≤4mm) were enrolled in this split-mouth prospective randomized controlled study. One sinus side as a control group was grafted with only collagenated heterologous bone graft; the other region as a test group was grafted with hyaluronic matrix and collagenated heterologous bone graft. Bone biopsy samples were taken after 4 months during the dental implant surgery and analyzed using micro-computed tomography and histomorphometric parameters. According to the micro-computed tomography and histomorphometric results, a significantly higher percentage of new bone was observed in the test group when compared to the control group after 4 months of healing. This study confirmed the hypothesis that the addition of hyaluronic matrix to collagenated heterologous bone graft for sinus augmentation enhances bone formation compared to collagenated heterologous bone graft alone in the early healing period.

The effects of adjunctive parathyroid hormone injection on bisphosphonate-related osteonecrosis of the jaws: an animal study.

Bisphosphonate (BP)-related osteonecrosis of the jaw (BRONJ) is a serious and challenging complication of chronic BP uptake in patients with osteoporosis who require management of skeletal-related events. The efficiency of adjunctive parathyroid hormone (PTH) injection was evaluated after chronic BP administration that was followed by tooth extraction. BRONJ was not observed in any of the subjects in the control groups, while BRONJ was observed in 66% and 22% of the subjects in the tooth extraction group and the tooth extraction with PTH injection group, respectively. In addition the presence and severity of inflammation was lower in the PTH injected group than in the tooth extraction group, but the difference was not statistically significant (P>0.01). In conclusion, the administration of 30µg/kg/day PTH during a period of 8 weeks had positive effects on the resolution of BRONJ, but further studies are required to verify the effectiveness of PTH in the treatment of BRONJ.

Evaluation of the Amor and ESSG classification criteria for spondylarthropathies in a Turkish population.

This study evaluated the Amor and European Spondylarthropathy Study Group (ESSG) classification criteria for spondyloarthropathies in Turkish patients seen from October 1990 to August 1993 at the Physical Medicine and Rehabilitation Department of the GATA Haydarpasa Training Hospital. The Amor and ESSG criteria were evaluated in 157 patients with spondylarthropathies and in 124 controls with a variety of other rheumatic diseases. The sensitivity, specificity, positive predictive value, and negative predictive value of each criteria set were calculated, as well as the sensitivity and specificity of each of the 24 criteria used in these sets. For Amor's criteria, sensitivity was 88.5%, specificity was 91.9%, positive predictive value was 93.3% and negative predictive value was 86.4%. For the ESSG criteria, sensitivity was 86.6%, specificity was 91.1%, positive predictive value was 92.5% and negative predictive value was 84.3%. No significant differences were found between the two criteria sets. Our data show that the Amor and ESSG criteria are of similar value for the classification of spondylarthropathies and are comparable in terms of sensitivity and specificity. They also demonstrate the need for monitoring patients with equivocal clinical patterns using both sets of criteria as tools that complement each other.