Tiu Janine, Waddell J Neil, Al-Amleh Basil, Jansen van Vuuren Wendy-Ann, Swain Michael V
Postgraduate student, Department of Oral Rehabilitation, Faculty of Dentistry, University of Otago, Dunedin, New Zealand.
Senior Lecturer, Department of Oral Rehabilitation, Faculty of Dentistry, University of Otago, Dunedin, New Zealand.
J Prosthet Dent. 2014 Sep;112(3):481-7. doi: 10.1016/j.prosdent.2013.11.012. Epub 2014 Mar 24.
A validated universal method requiring no human input is needed to capture and evaluate preparation geometries in a manner that can be used to see the correlation of different parameters.
The purpose of this study was to present a method of capturing and evaluating crown preparation geometry.
One manually machined acrylic resin block and 9 randomly selected preparations for ceramic complete crowns prepared by general dentists were selected and prepared. The specimens were scanned (3D scanner; Nobel Biocare), and buccolingual and mesiodistal cross section images were collected. The images were imported into digitizing software (Engauge Digitizer 4.1) to convert the outlines into x and y coordinates. Six points were chosen by using a set of algorithms, and the resulting parameters were calculated.
The acrylic resin block was milled with a 12 degree total occlusal convergence (TOC) instrument producing a 12.83 degree TOC. For the other specimens, average TOC values ranged from 18 degrees to 52 degrees. The mean average margin width was 0.70 mm, and the mean average base dimension was 6.23 mm. The surface area/volume ratio, resistance length, and limiting taper were also calculated.
The method described provides a basis for accurately evaluating preparation geometry without human input.
需要一种经过验证的通用方法，无需人工干预，以一种可用于观察不同参数相关性的方式来捕捉和评估预备体几何形状。
本研究的目的是提出一种捕捉和评估全冠预备体几何形状的方法。
选择一个手工加工的丙烯酸树脂块以及由普通牙医制备的9个随机选取的陶瓷全冠预备体并进行处理。对标本进行扫描（3D扫描仪；Nobel Biocare），并收集颊舌向和近远中向的横截面图像。将图像导入数字化软件（Engauge Digitizer 4.1），将轮廓转换为x和y坐标。使用一组算法选择六个点，并计算所得参数。
用总牙合面聚合度（TOC）为12度的器械铣削丙烯酸树脂块，产生的TOC为12.83度。对于其他标本，平均TOC值范围为18度至52度。平均边缘宽度为0.70毫米，平均基底尺寸为6.23毫米。还计算了表面积/体积比、抗力长度和极限锥度。
所描述的方法为无需人工干预即可准确评估预备体几何形状提供了基础。
