No abstract

The results of the present study indicate that treatment with tissue-level implants is potentially more advantageous than with bone-level implants for implant-supported fixed prostheses.

Background: During drilling of bone, which is common in clinical surgeries, heat generation increases local temperature in the drilling site. Transmission of excessive heat to the surrounding bone tissue can cause thermal osteonecrosis. Consequently, it may lead to failure of implants and fixation screws or delay in healing process. Using cooling is a method for limiting temperature elevation. Materials and methods: In this study, through comparing three conditions of drilling without cooling, external cooling with normal saline, and external cooling with OpSite spray, the efficiency of OpSite as coolant is studied. In this regard, 2 drill bit diameters, 3 drilling speeds, and 3 drilling feed-rates are considered as drilling variables in the experiments. Results: For the whole experiments, while cooling with normal saline resulted in lower maximum temperatures than without cooling condition, OpSite had even better results and limited the temperature elevation during drilling of bone efficiently. Conclusion: OpSite spray, which has lower infection risks than normal saline on one hand and lower maximum temperature rise with all combinations of drilling parameters on the other hand, can be considered in clinical surgeries for cooling applications.

Background: A potential method in drilling of bone is ultrasonic-assisted drilling. In addition, during the drilling of bone, which is common in clinical surgeries, excessive heat generation and drilling force may lead to damages in bone tissue, and thus to failure of implants and fixation screws or delay in healing process. The aim of this study was to appraise efficiency of ultrasonic-assisted drilling in comparison to conventional drilling.Methods: In addition to investigating drilling force and temperature elevation, their effects on arising osteonecrosis and micro-cracks were explored in ultrasonic-assisted and conventional drilling through histopathologic assessment and microscopic imaging. In this regard, three drilling speeds and two drilling feed-rates were considered as drilling variables in the in-vitro experiments. Moreover, numerical modeling gave an insight into temperature distribution during drilling process in the both methods and compared three different vibration amplitudes. Results: Although temperature elevations were lower in the conventional drilling, the ultrasonic-assisted drilling had lesser drilling forces. Furthermore, the latter method had smaller osteonecrosis regions, and did not have micro-cracks in cortical bone and destructions in structure of cancellous bone.Conclusions: The ultrasonic-assisted drilling, which caused lesser damages to the bone tissue in both cortical and cancellous bone, was more comparatively advantageous.

Background: During drilling of bone, which is common in clinical surgeries, heat generation increases local temperature in the drilling site. Transmission of excessive heat to the surrounding bone tissue can cause thermal osteonecrosis. Consequently, it may lead to failure of implants and fixation screws or delay in healing process. Using cooling is a method for limiting temperature elevation. Materials and Methods: In this study, through comparing 3 conditions of drilling without cooling, external cooling with normal saline, and external cooling with OpSite spray, the efficiency of OpSite as coolant is studied. In this regard, 2 drill bit diameters, 3 drilling speeds, and 3 drilling feed-rates are considered as drilling variables in the experiments. Results: For the whole experiments, while cooling with normal saline resulted in lower maximum temperatures than without cooling condition, OpSite had even better results and limited the temperature elevation during drilling of bone efficiently. Conclusion: OpSite spray, which has lower infection risks than normal saline on one hand and lower maximum temperature rise with all combinations of drilling parameters on the other hand, can be considered in clinical surgeries for cooling applications.