| Summary: | 碩士 === 國立臺北科技大學 === 機電整合研究所 === 104 === In recent years, dental implant surgery has become the first choice for edentulous patients. The success rate of the implant surgery is highly related to the stability and osseointegration of the implant. Also, the pre-formed drilling process in the implant surgery can greatly affect the osseointegration efficacy. However, previous literatures rarely considered the mechanical and thermal effects on the alveolar bone during the drilling sequence. Therefore, in the current study, a special finite element analysis (FEA) incorporating failure criterion and thermo-mechanical coupling was used to determine the effects of drill geometries on the drilling reaction force, drilling torque, and the temperature change of the bone during the final drilling process.
First, a commercial dental implant drill set (Nobel Biocare - Ø2.0, Ø2.4/2.8, Ø3.2 /3.6 and Ø3.8/4.2) was selected as the base model in this study. A drilling speed of 800 rpm and feed rate of 1 mm/sec was used throughout the drilling procedures for both the finite element analyses and experimental tests. And then, correlation analysis was used to compare the analytical results with the drilling experimental results. We found high correlation between the analysis and experiment results. Therefore, the feasibility of the simulation was verified. Finally, new sets of dental implant drills with taper shape were developed. The first generation new drill sets were designed using the diameters of the commercial dental implant drill sets as the size of the cone shape. The second generation new drill sets were designed according to the geometric shape of the commercial dental implant (NobelActive RP 4.3 x 10 mm). And then, Finite element simulations of the new drill sets were performed to evaluate their drilling efficiency and the bone temperature rise, respectively during drilling procedure. Moreover, FEA of dental implant insertion to the pre-drilled bone was performed to compare the difference of site preparation by three different drill sets.
The results showed that the newly designed dental implant drills can reduce the drilling reaction force and temperature rise. It indicates new drill sets performed well in bone drilling and the tapered shape can indeed effectively reduce the temperature generated during the drilling process. Moreover, the insertion torque of site preparation by three drill sets was evaluated. It was found that the maximum torque values of site preparation by the three drill sets (52.6, 39.2, 53.5 N-cm) were all roughly lie within the suggested range (30-50 N-cm) from literature. The maximum torque values for the commercial dental implant drill sets and the second generation new drill sets were a little higher than the upper value (50 N-cm) of the recommended range. If this dental implant (NobelActive RP 4.3 x 10 mm) was used for implant surgery for patients with good alveolar bone quality (D1, D2), the size of the site preparation by these two drill sets can only be larger in order to avoid damage of the alveolar bone by excessive insertion torque that can lead to the loosening of dental implant. This study could provide an important reference for designing new dental implant drills.
|
|---|
