Minimally-assisted tooth repair (MaTR) systems are envisioned to be capable of substituting for the skill of a dentist. If successfully developed, MaTR systems could enable lower-skilled dental technicians to provide dental care at a fraction of the overall medical cost. This paper explores a key initial step towards the development of such systems by quantifying the machining responses of pristine human teeth relevant to dental preparation procedures. The working hypothesis of the study is that such findings will enable the benchmarking of key process planning and control metrics relevant for the future development of MaTR systems. To this end, pristine human cadaver teeth were cut using a computer-controlled motion platform and dental hand-piece. Relevant cutting responses, such as cutting forces, in-process rotational speed of the dental bur, teeth morphology, and bur wear were captured. The trends in cutting forces show the potential for implementing region-specific process parameters for cutting the enamel and dentin regions of the tooth. A feed-per-tooth value of 0.1 µm at rotational speeds of 8 krpm and 50 krpm is seen to cut both the enamel and dentin regions at cutting forces lower than patient discomfort thresholds identified in literature. Cutting force signals were also successfully mapped against the CT-scan data of the tooth. This mapping indicates a clear identification of the enamel/dentin regions, and a transition region that is dependent on cutting parameters, tooth/tool geometry and tool pose. The trends in the in-process rotational speed of the dental bur indicate that stalling of the dental bur occurs at feed per tooth values greater than 0.25 µm. The evidence of stalling can be detected by both a drop in the cutting force signal and by surface morphology changes on the cut surface of the tooth. MaTR systems should be designed to avoid bur stalling regions by either operating at feed per tooth values ≤ 0.25 µm or by the use of dental spindles with higher torque capacity. Lastly, the type of fit present on the shank of the bur is seen to result in differences in the cutting force signals and wear of the cutting edges (flutes) of the dental bur. In general, a right-angle (RA) fit on the shank of the dental bur results in a larger tool runout leading to uneven loads on the flutes and increased tool wear. The friction grip (FG) fit avoids these problems and may be more suited for MaTR systems.

设想最小辅助牙齿修复（MaTR）系统可以代替牙医的技能。如果开发成功，MaTR系统可以使技术水平较低的牙科技师以总医疗费用的一小部分提供牙科护理。本文通过量化与牙齿制备程序相关的原始人牙的机械加工响应，探索了开发此类系统的关键的初始步骤。该研究的工作假设是，这些发现将使与MaTR系统的未来开发相关的关键过程计划和控制指标成为基准。为此，使用计算机控制的运动平台和牙科手机将原始的人类尸体牙齿切开。相关的切削响应，例如切削力，牙钻的加工速度，牙齿的形态和钻头磨损被捕获。切削力的趋势表明，有可能实施针对特定区域的工艺参数来切削牙齿的牙釉质和牙本质区域。可以看到，在8 krpm和50 krpm的转速下，每齿进给值为0.1 µm，可以以低于文献中确定的患者不适阈值的切削力切削牙釉质和牙本质区域。切削力信号也已成功地映射到牙齿的CT扫描数据上。该映射表明了对牙釉质/牙本质区域的清晰识别，以及取决于切削参数，牙齿/工具的几何形状和工具姿势的过渡区域。牙钻的加工中转速的趋势表明，当每齿进给量大于0.25 µm时，牙钻会失速。失速的迹象可以通过切削力信号的下降和牙齿切削表面的表面形态变化来检测。MaTR系统的设计应避免在每齿进给值≤0.25 µm的情况下工作或通过使用具有更高扭矩能力的齿锭来避免钻头失速区域。最后，可以看到牙钻柄上的配合类型导致切削力信号和牙钻的切削刃（排屑槽）磨损的差异。通常，在牙钻刀柄上安装直角（RA）会导致较大的刀具跳动，从而导致排屑槽上的载荷不均匀并增加了刀具的磨损。摩擦握把（FG）的安装避免了这些问题，并且可能更适用于MaTR系统。