Thermal necrosis-aided dental implant removal:A rabbit model pilot study

The significant advances in the materials and biological aspects of dental implants haven?t completely eradicated the implant failures. The removal of osseointegrated but otherwise failed implants present several challenges including adjacent tissues damage and necessity of bone augmentation for reimplantation. Controlled thermal necrosis has emerged as an alternative technique to aid removal of osseointegrated dental implants with minimal to no defect to healthy bone or surrounding tissues. This study aimed to evaluate the thermal necrosis-aided implant removal method in a rabbit osseointegration model. A total of 8 male New Zealand rabbits were used in the study. Two dental implants were placed on each femur of the rabbits. Heating of the implants was performed after 7 weeks following the implantation. Heating was done by contacting the tip of an electrosurgey tool in monopolar mode at different power settings and contact durations (5W ? 2 seconds, 5W ? 10 seconds, and 10 W ? 10 seconds). No heating was done on the control group. Implant stability right after implantation, before heat application and after heat application was determined using an Osstell? Mentor Device. Following the removal of implants histological analyses were performed to determine the effects of heat application at cellular level. ISQ values of the 10W-10s group was significantly lower compared to the other groups (p<0.001). No indication of progressive necrosis or irreversible damage was observed in any of the groups. However, the percent of empty-apoptotic lacunae were statistically higher in the 5W-10s and the 10W-10s groups compared the control and the 5W-2s groups. Within the conditions of this study, we conclude that heat application with an electrosurgery tool using monopolar mode at 10W power for 10 seconds is optimal for reversing osseointegration with no extensive or progressive damage to the bone

Beneficial effects of melatonin and BQ-123 on the rat testis damage caused by cigarette smoke

Background/aim: Several studies have demonstrated that cigarette smoke has detrimental effects on testicular function. However, it is unknown whether melatonin or BQ-123 has beneficial effects on the rat testis damage caused by cigarette smoke. The aim of the present study was to investigate the beneficial effects of melatonin or BQ-123 on the testicular damage caused by cigarette smoke. Materials and methods: Twenty Wistar rats were randomly divided into 4 equal groups: control group (n = 5), cigarette smoke group (n = 5), melatonin group (n = 5), and BQ-123 group (n = 5). At the end of 4 weeks, all the rats were sacrificed for histopathological evaluation and subsequent stereological analysis. The optical fractionator counting method, the most efficient and unbiased method, was used to estimate the total number of spermatogonia and spermatocytes. Results: All the control testes demonstrated complete spermatogenesis. There was a significant decrease in the germ cells of rats exposed to cigarette smoke for 4 weeks. After the application of melatonin or BQ-123, the total number of spermatogonia and spermatocytes in the testes was significantly higher. Conclusion: Based on these findings, melatonin and BQ-123 are able to minimize the degenerative effects of cigarette smoke by increasing the germ cell count.Gaziosmanpasa University Research FundGaziosmanpasa University [2006/19]This study was supported by Gaziosmanpasa University Research Fund Project no. 2006/19. We thank Dr Bahadir Ungor (rest in peace) for all his assistance