Avaliação da linha de terminação cervical de preparos protéticos submetidos a diferentes métodos de acabamento

Abstract

Evaluate the effectiveness of different instruments used for polishing the finish line of prosthetic preparations. Forty-eight extracted third molars with similar dimensions were selected. Teeth were prepared for prosthetic treatment with a diamond tip at high speed handpiece only in the buccal surface. So, they were divided into four experimental groups (n=12) according to the method of polishing the finish line: Group 1 (manual instrument), Group 2 (multilayered bit), Group 3 (diamond tip) and Group 4 (diamond tip for Ultrasound). The polish was performed for only half of the buccal surface of each tooth. After the finishing procedures, the specimens were subjected to analysis in Scanning Electron Microscope (SEM). Standardized focalizations were performed for all teeth in the polish side and the control side (40x). The images were organized in Microsoft PowerPoint 2010. Seven specialized professionals were selected for the evaluation of the finish lines of the images using this classification: 1-poor, 2-regular, 3-good, 4-excellent. These same professionals have visual contact with the specimens and evaluated according to the same score. The images were also analyzed quantitatively with the counting defects tool of Adobe Photoshop CC. The qualitative analysis were statistically analyzed with the Friedman test (p<0.05), while quantitative evaluation by analysis of variance (ANOVA) and Tukey HDS test (p<0.05). Qualitative analysis of the images showed better results for the group submitted to polishing with Ultrasound (Group 4). Visual analysis confirmed the effectiveness of the Ultrasound, with a lower percentage of poor preparations (6.3%) and the highest percentage of excellent preparations (33.3%) compared to other groups. Quantitatively, group 4 had the lowest mean defect and differed statistically significantly from group 2, who presented with the highest mean value of defects. The groups with and without polishing did not statistically differ from themselves. The finishing procedures can interfere positively or negatively on the regularity of finish line. Best preparations were those who maintained a tip of the same format that the preparation was performed (Diamond and Ultrasound tip).