Objective To study the Thermogenesis mechanism of bone during digital dental implant surgery with guide plates and to analyse the cooling effect of bone under three kinds of different irrigation methods (internal cooling, regular external cooling and jet cooling).
Methods Using DuraForm nylon to replace cortical bone, a 2 mm diameter drill was selected to prepare a hole with depth of 10 mm, and simulating procedure of digital plant operation. A NC platform was built to control the drilling rate. At the same time, the small thermocouples were embedded at a serials deepness of 4, 6, 8 and 10 mm, and in the direction of radius the couples were distributed from 0.5 mm to 6.0 mm away from hole wall at intervals of 0.5 mm. Through temperature measurement instrument and the temperature record software,every measuring point temperature during the process of drilling was recorded, and the cooling effect between internal cooling, regular cooling and jet cooling was compared.
Results When preparing a hole at the depth of 10 mm, the heat-affected zone was in the scope of 6 mm being away from hole wall(2 mm in diameter), and there was a highest temperature at the depth of 6 mm, and the highest temperature arrived 46.2℃ in regular cooling group, the highest temperature of internal cooling group and the jet cooling group was 24.6℃ and 12.5℃ respectively.
Conclusion Drilling a hole with guide plates,the internal cooling have the best cooling effect, while cooling effect of the conventional drill bit is not good. But using jet cooling,combined with designed cooling channel on the guide template can be matched with obtain favorable result and significantly reduce the temperature of bone tissue in the process of drilling hole. In addition, using conventional to drill hole in the process of pulling the drill bit by several times, can get a certain cooling conditions and obtain a certain degree of cooling effect.
DownLoad: