Bignardi Cristina, Zanetti Elisabetta M, Terzini Mara, Ciccola Anna R, Schierano Gianmario, Audenino Alberto L
Department of Mechanical and Aerospace Engineering, Polytechnic University of Turin, Turin, Italy.
Departiment of Engineering, University of Perugia, Perugia, Italy.
Open Biomed Eng J. 2018 Jun 29;12:27-35. doi: 10.2174/1874120701812010027. eCollection 2018.
Tooth-supported fixed dentures are commonly used in restorative dentistry, and have definitely reached a high survival rate; nevertheless, their removal is sometimes required mainly due to caries or other failures (poor fit, poor cementation and so on). Removing a definitive partial denture is not trivial since the used cement is not always known and it may be very resistant; additionally, there are various clinical circumstances in which a conservative disassembly would be desirable.
assessing the performance of different tools for cement crowns retrieval in terms of reliability, learnability and efficiency.
An experimental study has been performed on two different devices for conservative crown/bridge removal: a manual tool that is a sliding hammer, and an automatic tool, powered by compressed air. Both skilled and unexperienced operators have been considered and an experimental set up has been appositely designed in order to measure force versus time patterns. The peak applied force has been taken as an output variable for the evaluation of tool performance.
The automatic tool improves both the inter-operator and the intra-operator reliability, respectively from 79% to 95%, and from 69% to 92%. Additionally, the force pattern is significantly different between these two tools: the instrument powered by compressed air, produces a sharper peak force, as required to break fragile materials such as dental crown cement, and its efficiency can be estimated to be 75% higher. Both tools have a high learnability since the performances of experienced and unexperienced operators have not proved to be significantly different.
A methodology has been set up to compare tools for cement crowns retrieval. The compressed-air tool has been proved to generally provide a better performance unless more ductile cement is to be broken.
牙支持式固定义齿在修复牙科中常用，且存活率已达到很高水平；然而，有时仍需要将其拆除，主要原因是龋齿或其他故障（贴合不良、粘结不佳等）。拆除固定局部义齿并非易事，因为所用粘结剂往往未知且可能非常坚固；此外，在各种临床情况下，都希望能进行保守拆卸。
评估不同工具在取出粘结冠方面的可靠性、易学性和效率。
对两种用于保守拆除冠/桥的不同装置进行了实验研究：一种手动工具是滑锤，另一种自动工具由压缩空气驱动。研究考虑了熟练和不熟练的操作人员，并专门设计了一个实验装置来测量力随时间的变化模式。将施加的峰值力作为评估工具性能的输出变量。
自动工具提高了操作人员之间和操作人员内部的可靠性，分别从79%提高到95%，以及从69%提高到92%。此外，这两种工具的力模式有显著差异：由压缩空气驱动的工具产生的峰值力更尖锐，这是打破牙冠粘结剂等易碎材料所需要的，其效率估计高75%。两种工具都具有很高的易学性，因为经验丰富和经验不足的操作人员的表现没有显著差异。
已建立一种方法来比较取出粘结冠的工具。事实证明，除非要打破更具韧性的粘结剂，压缩空气工具通常能提供更好的性能。
