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

Investigation the Effect of Human Recombinant Epidermal Growth Factor on Rotator Cuff Healing: An Experimental Model

Abstract Objective To investigate the effectiveness of human recombinant epidermal growth factor in the healing of rotator cuff tear in the rabbit shoulder. Methods Rotator cuff tears (RCTs) were experimentally created on both shoulders of 20 New Zealand rabbits. The rabbits were divided into the following groups: RCT (sham group; n = 5), RCT + EGF (EGF group; n = 5), RCT + transosseous repair (repair group; n = 5), and RCT + EGF + transosseous repair (combined repair + EGF group; n = 5). All rabbits were then observed for 3 weeks, and biopsies were taken from the right shoulders in the third week. After three more weeks of observation, all rabbits were sacrificed, and a biopsy removed from their left shoulders. All biopsy material was stained with haematoxylin & eosin (H&E) and vascularity, cellularity, the proportion of fibers and the number of fibrocartilage cells were evaluated under light microscope. Results The highest collagen amount and the most regular collagen sequence was detected in the combined repair + EGF group. The repair group and the EGF group showed higher fibroblastic activity and capillary formation when compared with the sham group, but the highest fibroblastic activity and capillary formation with highest vascularity was detected in the combined repair + EGF group (p < 0.001). EGF seems to improve wound healing in the repair of RCT. The EGF application alone, even without repair surgery, seems to be beneficial to RCT healing. Conclusion In addition to rotator cuff tear repair, application of human recombinant epidermal growth factor has an effect on rotator cuff healing in rabbit shoulders