可摘局部义齿基牙精确预备刚性引导机制和关键技术研究

Removable partial denture (RPD) is still a classic and important way of repairing the partial edentulous jaw. The teeth preparation of abutment is the key point determining the quality of RPD restoration, which depends on the experience of the dentist resulting in low precision and accuracy. In recent years, quantitatively guided technique for teeth preparation is introduced to reduce the difficulty and improve the efficiency and quality for tooth preparation of crown. However, quantitatively guided technique for teeth preparation has been used for crown of single tooth, not for abutment teeth of RPD, which come from the literature reports. This study aims to explore the rigid guide mechanism and the digital designing method of three-dimensional pathway of bur on abutment teeth preparation of RPD, based on which the guide plate for precise teeth preparation is designed and manufactured with digital methods. Then the possibility and precision of the three-dimensional rigid guide pathway are evaluated. As a result, the abutment teeth preparation of RPD could be quantitatively guided in three-dimensional direction, leading to improving the accuracy and efficiency for abutment preparation of RPD and transferring the important information coming from surveying to the prepared teeth accurately, which could result in improving the precision and reducing the empirical dependence of RPD restoration. Furthermore, combined with the computer-aided design/computer-aided manufacturing method for one-piece RPD established by our team, the possibility of that teeth preparation and try-in of RPD restoration would be finished at the same appointment could be explored, which could reduce the treatment times for the processes of RPD restoration.

可摘局部义齿（RPD）目前仍是牙列缺损经典和重要的修复方式，而基牙预备是决定RPD修复质量的关键因素，其预备量主要靠专家经验确定，精确性差。近年来，国内外主要采用牙体预备定量引导技术降低全冠牙体预备的难度，提高牙体预备的质量和效率，但针对RPD的牙体预备定量引导技术的研究未见报道。本项目拟探究RPD基牙精确预备的刚性引导机制，率先建立RPD基牙精确预备刚性引导结构及车针运动三维轨迹数字化设计方法，进而设计具有良好三维刚性约束效果的牙体预备导板，最后验证其可行性和精确性。本项目将实现RPD基牙精确预备的三维定量引导，提高RPD基牙预备的精度、准确度和效率，使模型观测的信息能精确转移到牙体预备中，提高RPD修复的精确性。与本课题组已建立的一体化RPD数字化设计和制作技术相结合，可进一步探索单次就诊同时完成RPD牙体预备与修复体戴入的可行性，减少RPD修复的就诊次数，突破其诊疗周期瓶颈。

牙体预备是决定可摘局部义齿(RPD)修复质量的关键因素,目前其预备质量主要依赖专家经验，精确性差。国内外针对RPD牙体预备定量引导技术的研究尚未见报道。本项目探究了RPD基牙精确预备的三重刚性引导机制和效果,率先建立了RPD基牙导平面、支托凹精确预备三重刚性引导结构,进而设计具有良好六自由度刚性约束效果的牙体预备导板。在该导板辅助下，导平面预备的三维精度由150-200μm提高到50μm，方向精度由8度提高到1度；支托凹预备的正确度由253.4±38.8μm提高到138.1±30.3μm，精密度由231.6±84.8μm提高到115.1±45.1μm；支托凹在深度、凹底倾斜形态等方面也优于传统自由手预备，更符合临床要求。本项目提高了RPD基牙牙体预备的精度、准确度和效率，使模型观测确定的重要信息能精确转移到口内形成有效引导,提高RPD修复的精确性，减少经验依赖，并能辅助实现单次就诊同时完成RPD牙体预备和修复体戴入，突破RPD的诊疗周期瓶颈。