Umut Tekin

Effects of Alendronate on Rate of Distraction in Rabbit Mandibles

PURPOSE Bisphosphonates are used for inhibiting bone resorption in several diseases. In this experimental study, the effects of alendronate on the mandibular distraction gap in rabbits at 2 different rates were evaluated. MATERIALS AND METHODS The study was performed using 15 New Zealand white rabbits. Group 1 consisted of animals with distraction at the rate of 1 mm/day. Group 2 consisted of animals with distraction at the rate of 2 mm/day. These experimental groups had a postoperative alendronate injection during the first 3 days of their distraction phase. Group 3 consisted of animals with distraction at the rate of 1 mm/day, without alendronate injections. Distraction was performed on only the left sides of all animals until a gap of 10 mm was achieved. On postoperative day 45, the animals were sacrificed, and the mandibles of all animals were evaluated radiographically and histologically, and with dual-energy x-ray absorptiometry (DEXA). Radiographic images were also evaluated using transmission densitometry (TD). RESULTS Histologically, bone healing was found to be significantly accelerated in groups 1 and 2 compared with group 3 (P < .05). Bone healing was superior in group 2, but the difference was not statistically significant compared with group 1. The TD results revealed no statistical difference between experimental groups, whereas the results for group 2 showed significantly denser osteogenic formation in the distraction gap compared with group 3. There was a significant increase in mean bone mineral density in the experimental groups compared with the control group. CONCLUSION Histologic, TD, and DEXA results showed that alendronate injections during the distraction phase may be effective in accelerating new bone formation in the distraction gap in rabbit mandibles. The TD results also support the concept that an administration of alendronate may allow a 2 mm/day elongation instead of 1 mm/day in the rabbit mandible.

Piezosurgery Versus Conventional Surgery in Radicular Cyst Enucleation

Objective This study compared the use of piezosurgery and conventional surgery in radicular cyst enucleation. Study Design The study was conducted with 29 patients who were radiologically and cytologically prediagnosed with radicular cysts in the jaw region. Nineteen patients were treated using piezosurgery, and 10 were treated using conventional surgical procedures. Surgical procedures were evaluated according to the following criteria: hemorrhage, soft-tissue damage, manipulation complexity, major perforation areas on the enucleated cyst tissue, and approximate operation duration. Patients were monitored postoperatively and evaluated for hemorrhaging at 24, 48, and 72 hours following surgery. Follow-up was conducted to check for recurrences and ranged from 5 to 24 months. Results No complications were observed in any of the 20 patients treated using piezosurgery, although the duration of surgery was longer than expected. Of the 10 patients treated using conventional methods, hemorrhaging that affected the operation occurred in 3 cases, perforation of the cyst epithelium and difficulties in enucleation occurred in 5 cases, postoperative hemorrhage occurred in 2 cases, and recurrence was observed in 2 cases. Conclusions Piezosurgery may be considered effective in procedures such as enucleation that require sensitive manipulation, despite the increase in the length of the overall surgical procedure. Given the results of the present study and the current lack of information in the literature regarding postoperative pain, infection, and long-term success rates associated with the use of piezosurgery in cyst enucleation, further study in this area is recommended.

Tumor necrosis factor-alpha levels in the synovial fluid of patients with temporomandibular joint internal derangement

PURPOSE The purpose of this study was to investigate the level of tumor necrosis factor-alpha (TNF-α) in the synovial fluid (SF) of patients with temporomandibular joint (TMJ) internal derangement and to show the relationship between the level of TNF-α and the severity of the disease. MATERIALS AND METHODS Arthrocentesis was performed on 32 female and five male patients (aged between 17 and 45) referred to our clinic with the complaint of TMJ pain and discomfort. TNF-α levels were determined in the SF samples obtained during arthrocentesis. As a measure of pain, visual analog scale (VAS) scores were also evaluated. RESULTS There were statistically significant differences in VAS scores between the stages. VAS scores were found to be elevated as the stage of disease progressed. Increased levels of TNF-α were found in progressive stages of internal derangement. CONCLUSION In our study, both SF TNF-α levels and pain levels (VAS scores) were found to be increased in patients with internal derangement as the stage of the disease progresses. TNF-α might contribute to the pathogenesis of synovitis and the degeneration of the TMJ cartilage and bone.

Biomechanical evaluation of a new design titanium miniplate for the treatment of mandibular angle fractures

The optimal management of mandibular angle fractures remains controversial. The aim of this experimental study was to test the stability and resistance to mechanical force of a new titanium miniplate design. Thirty fresh sheep hemimandibles, sectioned at the angle region, were used to evaluate two plating techniques. One group received fixation via a new design single non-compression titanium miniplate and the second group via a six-hole straight non-compression titanium miniplate. A custom-made biomechanical test model was used for the samples. Each hemimandible was subjected to compressive and tensile forces using an Instron machine. The biomechanical forces (N) that caused 4-mm displacement or fixation loosening were compared. Comparison between the groups showed that fixation with the new design miniplate had more resistance to lateral compression forces than with a six-hole straight miniplate (P<0.009). Moreover, the new design miniplate fixation displayed more resistance to vertical compression and tensile forces (P>0.46 and P>0.61, respectively). The study demonstrated that mandibular fracture fixation with the new design non-compression titanium miniplate offered greater resistance to lateral displacement forces and may also provide increased resistance to vertical compressive and tensile forces than a conventional six-hole straight miniplate.

Effect of Platelet-Rich Fibrin on Peripheral Nerve Regeneration.

Purpose:This study aimed to evaluate the effect of platelet-rich fibrin (PRF) on peripheral nerve regeneration on the sciatic nerve of rats by using functional, histopathologic, and electrophysiologic analyses. Materials and Methods:Thirty female Wistar rats were divided randomly into 3 experimental groups. In group 1 (G1), which was the control group, the sciatic nerve was transected and sutured (n = 10). In group 2 (G2), the sciatic nerve was transected, sutured, and then covered with PRF as a membrane (n = 10). In group 3 (G3), the sciatic nerve was transected, sutured by leaving a 5-mm gap, and then covered by PRF as a nerve guide (n = 10). Functional, histopathologic, and electrophysiologic analyses were performed. Results:The total histopathologic semiquantitative score was significantly higher in G1 compared to G2 and G3 (P < 0.05). Myelin thickness and capillaries were significantly lower in G3 compared to G1 (P < 0.05). There was no statistically significant difference between the groups with regard to the functional and electrophysiologic results. Conclusion:The study results suggest that PRF decreases functional recovery in sciatic nerve injury. Further studies are required to determine the efficacy of PRF on peripheral nerve regeneration.

Correction of postsurgical alveolar ridge defect with vertical alveolar distraction of the onlay block graft.

Alveolar bone augmentation for dental implant rehabilitation is one of the greatest challenges for oral and maxillofacial surgeons. Bringing out an inadequate quantity of vertical bone during augmentation compromises correct implant positioning and the resulting prosthetic restoration. Alveolar distraction osteogenesis is now generally used in correcting alveolar ridge atrophy due to trauma, congenital defects, or periodontal defects. Onlay block grafting is a suitable method for restoring the alveolar bony defects. However, it sometimes can become a complicated procedure to repair the horizontal defect accompanying a vertical defect using only bone blocks. This clinical report presents a successful reconstruction of a severe anterior mandibular alveolar bony defect as a result of impacted teeth extraction and periodontal problem in a 50-year-old healthy female patient. The defect was reconstructed with symphysis graft and platelet-rich fibrin in the first step. Vertical alveolar distraction was performed on the grafted site to maintain the suitable bony height 3 months later. Grafted bony segment distraction and the treatment options in similar cases were also discussed in this clinical report among with the literature.

Malondialdehyde Levels in Dental Follicles of Asymptomatic Impacted Third Molars

PURPOSE Increased levels of reactive oxygen species lead to oxidative stress and tissue damage. Malondialdehyde (MDA) is one of many low-molecular-weight endproducts of lipid peroxidation that increases with oxidative stress. The aim of this study was to determine oxidative stress in dental follicles (DFs) of radiologically asymptomatic impacted third molars (ITMs) using MDA. MATERIALS AND METHODS This study involved 40 DFs of 40 patients referred for clinically and radiographically asymptomatic ITMs. Forty healthy gingival tissues in the same patients were obtained during surgical removal of teeth as a control group. DF widths on periapical radiographs narrower than 2.5 mm were included in the study. All tissues samples were analyzed for MDA as an indicator of oxidative stress. RESULTS Levels of MDA were significantly higher in DFs from ITMs than those from healthy gingival tissues of the same patients (P < .01). CONCLUSION The results suggest that significant oxidative stress may occur in DFs of asymptomatic ITMs. The findings suggest that increased MDA may play an important role in oxidative stress in DFs. In light of these preliminary findings of the present study, further investigations and comprehensive studies are required to determine the role of antioxidants that scavenge free radicals in DFs.

Finite-Element Analysis of a New Designed Miniplate which is Used via Intraoral Approach to the Mandible Angle Fracture: Comparison of the Different Fixation Techniques.

AbstractThe mandible is the largest facial bone as well as the most commonly fractured bone in the maxillofacial region. Despite numerous studies conducted to identify optimal treatment modalities and plates configurations for intraoral and transoral approaches, no definitive conclusion has been reached.This study used finite element analysis (FEA) to assess 4 scenarios for treatment of an angle fracture (6-hole noncompression miniplate; 6-hole single plate/Champys technique, 3D strut plate; 2 parallel 4-hole noncompression miniplates). Analysis included segmental displacement and Von Mises Stress evaluations of a 3D reconstruction of a human mandible.Von Mises Stress values for plates did not vary significantly among treatment groups. Moreover, no significant differences were observed in cumulative displacement of segments subjected to vertical and horizontal loads, with all treatment configurations demonstrating clinical acceptability.

Effects of Local Low-dose Alendronate Injections Into the Distraction Gap on New Bone Formation and Distraction Rate on Distraction Osteogenesis

Abstract Bisphosphonates that constrain bone resorption have a direct effect on osteoclast function. In this experimental study, the effects of low-dose local alendronate injections on the distraction gap (DG) in rabbit mandible at 2 different rates were evaluated. The experimental study was conducted on 20 male, New Zealand white rabbits. The animals were divided into 3 experimental groups and 1 control group. Group 1 consisted of animals with distraction at the rate of 1 mm/day, receiving postoperative local low-dose alendronate local injections into the DG. Group 2 consisted of animals with distraction at the rate of 2 mm/day, receiving postoperative 0.75 &mgr;g/kg of alendronate local injections into the DG. Group 3 consisted of animals with distraction at the rate of 2 mm/day, receiving postoperative 0.2 mL local saline injections into the DG. Group 4 consisted of animals with distraction at the rate of 1 mm/day, receiving postoperative 0.2 mL local saline injections into the DG. All the injections were performed immediately postoperatively and for all groups at 1, 2, 3, and 4 weeks following surgery. The distraction zones were evaluated using dual-energy X-ray absorptiometry and histological analysis. Histologically, bone healing was found to be significantly accelerated in Groups 1 and 4 compared with Groups 2 and 3 (P < 0.05). Bone healing was superior in Group 1 and the difference was statistically significant compared with Group 4. There was a significant increase in mean bone mineral density in the 1 mm daily rate groups (Groups 1 and 4) compared with the 2 mm daily rate groups (Groups 2 and 3) (P < 0.05). Local low-dose alendronate injections could be an effective way for improving bone formation in distraction osteogenesis. Furthermore, the results of this study did not support the hypothesis that injections of local low-dose alendronate may allow 2 mm/day instead of 1 mm/day of elongation in the rabbit mandible.

Reconstruction of a patient with Rosai-Dorfman disease using ramus graft and osseointegrated implants: a case report.

R osai-Dorfman disease (RDD), or sinus histiocytosis with massive lymphadenopathy, is a rare and benign, frequently self-limited histiocytic disorder of unknown etiology. The most common clinical findings are broad painless lymphadenopathy accompanied by fever, weight loss, tonsillitis, rhinorrhea, nasal obstruction, and sometimes hepatosplenomegaly. Laboratory findings in patients with RDD include an elevated erythrocyte sedimentation rate, anemia, leukocytosis and polyclonal hypergammaglobulinemia. RDD classically presents with painless massive cervical lymphadenopathy, which is caused by accumulation of lymphocytes and histiocytes distending the lymph node sinuses. However, the disease may occur at extranodal sites. In most instances, the extranodal sites include the eyes, head and neck, skin, or bone. Mandibular cortical grafts are the gold standard in the restoration of intraoral osseous defects. These grafts do not produce immune reactions and are incorporated by osteoclastic resorption with a short healing period when compared with other methods of osseous repair. Intraoral donor sites include the mandibular ramus, angle of the mandible, mandibular symphysis, and mandibular exostoses. The mandibular ramus provides primarily a dense cortical graft. Other advantages of a mandibular ramus transplant are minimal resorption, maintenance of osseous density, intraoral access, and proximity to the recipient site. Cortical grafts, including the ramus, are reliable donor sites for the reconstruction of the alveolar ridge deformities before dental implant placement. The highest concentrations of promoter proteins (eg, bone morphogenetic proteins) are found in the mandibular cortical grafts. This report presents a case of an isolated RDD involving the mandible as well as its surgical management, preprosthetic reconstruction, and restoration with dental implants.