Ayad Mohamed F, Johnston William M, Rosenstiel Stephen F
Section of Restorative Dentistry, Prosthodontics, and Endodontics, University of Tanta, Tanta, Egypt.
J Prosthet Dent. 2009 Aug;102(2):81-8. doi: 10.1016/S0022-3913(09)60114-1.
Although it is known that different dental rotary instrument types produce distinct surface roughness of the axial walls which may contribute to the clinical performance of a cast restoration, the ideal roughness that produces optimum wetting at the adhesive interface is unclear.
The purpose of this study was to characterize the surface roughness and its influence on wettability of teeth prepared for complete veneer crowns with different dental rotary instruments.
Sixty standardized tooth preparations for complete crowns were completed using a modified milling machine on extracted human teeth with diamond, tungsten carbide finishing, and cross-cut carbide rotary instruments of similar shape (n=20). Morphological changes obtained were investigated with a surface texture analyzer. Two additional specimens from each group were treated and prepared for scanning electron microscopy. The contact angle of a drop of distilled water on each of the prepared surfaces was used as the measure of wettability with a goniometer microscope. The data were analyzed with 1-way ANOVA and Tukey's Honestly Significant Difference (HSD) test (alpha=.05).
Surface preparation resulted in significant differences for surface topography and wettability (P<.001). The carbide burs had significantly higher mean roughness readings (SD) for all parameters: Ra (8.6 (1.9) microm), Rq (10.9 (2.2) microm), and Ry (41.1 (2.1) microm), except for the mean Rz (12.1 (3.1) microm) value, which was recorded for diamonds. The other roughness parameters for the diamond rotary instruments were intermediate. Teeth completed with carbide finishing burs produced a smoother surface Ra (1.2 (0.5) microm), Rq (1.6 (0.6) microm), Ry (6.4 (2.6) microm), and Rz (1.9 (0.6) microm). The highest mean contact angle (SD), 81.5 (9.1) degrees, was associated with diamond rotary instruments, and the lowest (75.3 (5.9) degrees) was recorded for finishing burs. The contact angle for teeth prepared with tungsten carbide burs was intermediate: 76.1 (5.9) degrees.
The selection of dental rotary instruments for tooth preparation significantly affects surface roughness and wettability of dentin, which may influence the retention of cast restorations.
尽管已知不同类型的牙科旋转器械会在轴壁上产生不同的表面粗糙度，这可能会影响铸造修复体的临床性能，但在粘接界面产生最佳润湿性的理想粗糙度尚不清楚。
本研究的目的是表征使用不同牙科旋转器械制备全冠修复体的牙齿表面粗糙度及其对润湿性的影响。
使用改良铣床，用形状相似的金刚石、碳化钨精修和交叉切割碳化钨旋转器械对60颗用于全冠修复的标准离体人牙进行制备（每组n = 20）。用表面纹理分析仪研究获得的形态变化。每组另外选取两个样本进行处理并制备用于扫描电子显微镜观察。用测角显微镜测量蒸馏水在每个制备表面上的接触角，以此作为润湿性的指标。数据采用单因素方差分析和Tukey's 真实显著差异（HSD）检验进行分析（α = 0.05）。
表面处理导致表面形貌和润湿性存在显著差异（P <.001）。除了金刚石组记录的平均Rz值（12.1（3.1）μm）外，碳化钨车针在所有参数上的平均粗糙度读数（标准差）显著更高：Ra（8.6（1.9）μm）、Rq（10.9（2.2）μm）和Ry（41.1（2.1）μm）。金刚石旋转器械的其他粗糙度参数处于中间水平。用碳化钨精修车针制备的牙齿表面更光滑，Ra为（1.2（0.5）μm）、Rq为（1.6（0.6）μm）、Ry为（6.4（2.6）μm）、Rz为（1.9（0.6）μm）。平均接触角（标准差）最高的是金刚石旋转器械组，为81.5（9.1）度，最低的是精修车针组，为75.3（5.9）度。用碳化钨车针制备的牙齿的接触角处于中间水平：76.1（5.9）度。
选择牙科旋转器械进行牙齿制备会显著影响牙本质的表面粗糙度和润湿性，这可能会影响铸造修复体的固位。
