The Effect of Different Techniques and Applications on Margin Surface Roughness in Crown Finish Line Creation

The Effect of Different Techniques and Applications on Margin Surface Roughness in Crown Finish Line Creation Aim: This study compares the surface roughness of margin finish lines prepared using handpieces at two different rotational speeds and a sonic handpiece on teeth with similar preparation. Materials and Methods: This thesis used 32 extracted canine teeth with intact structural integrity to form four groups for each test method. After completing the preparation in the chamfer configuration, the margin finish was prepared using rotary handpieces and ultrasonic devices. Surface roughness measurements were taken from the surfaces of the samples in each experimental group using a profilometer. The samples' surface morphology and elemental analysis were examined using Scanning Electron Microscopy and Energy Dispersive Spectroscopy (SEM-EDS Analysis). Surface roughness was compared by selecting one sample from each group that underwent surface treatment using Atomic Force Microscopy (AFM), which provides a three-dimensional surface topography. Data were analyzed using version 4.4.1 of the R programming language. One-Way ANOVA compared variables that fit a normal distribution in binary groups. Quantitative data were presented as mean ± standard deviation. The significance level was set at p<0.05. The normality of the data distribution was determined using the Shapiro-Wilk test. Data were analyzed with Minitab v14. A Generalized Linear Model was used to compare values fitting a normal distribution according to sonic and speed, and the Bonferroni method was used for multiple comparisons to determine differences between factor level means after variance analysis. Results: It was found that there were statistically significant differences in the average Ra, Rq, Ry, and Rz values among the groups (p<0.001). All groups showed differences from each other, with the highest average value in Group 1, where the margin surface was created without using Sonic at the recommended RPM speed, and the lowest average value in Group 4, where the margin surface was created using Sonic at half the recommended RPM speed. There are differences among all interactions, with the highest Ra value obtained in those without sonic application and at full speed and the lowest average Ra value obtained in those with half-speed sonic application. When examining the surface roughness values of the surfaces created by the devices used in margin surface formation in tooth preparation, the factor with the highest impact was sonic, while speed had the least impact. Keywords: Tooth preparation, Margin finish line, Surface roughness, Ultrasonic devices, Prosthetic restoration