Influência dos diferentes fluxos de trabalho CAD/CAM na precisão e qualidade dos contatos proximais e oclusais em coroas de dissilicato de lítio

Abstract

The purpose of this in vitro study was to evaluate the effect of the digital workflow using different CAD / CAM systems (Chairside and InLab) in lithium disilicate crowns, regarding the reproducibility and the quality of occlusal and proximal contacts. Lithium disilicate crowns were produced (n=50) and divided into the following groups: -Three chairside CAD / CAM workflows: CEREC Bluecam (n = 10), CEREC Apollo Di CAI (n = 10), 3Shape TRIOS (n = 10) and two InLab CAD / CAM workflows: CEREC InEos X5 (n = 10) and 3Shape D900 (n = 10). Images of occlusal and proximal contacts calculated from virtual models were compared to images of real contacts, identified through carbon, in milled crowns that were fixed with elastomer to simulate cementation. The images were inserted into a software in a randomized way and evaluated by 3 blind and calibrated evaluators through questionnaires and a visual analogue scale (VAS). The Kruskal-Wallis Test and the Mann Whitney Post-test with Bonferroni corrections (statistical significance of 0.0083) were used to compare the proximal contacts of the clinically simulated crowns and the proximal contacts of the virtual crowns. Statistically significant differences (p <0.001) were found, in which the Bluecam (M = 6.48) and ApolloDi (M = 6.15) systems obtained better mean values compared to Ineos (M = 3.65) and 3Shape D900 (M = 3.41). TRIOS (M = 4.60) obtained similar results to both groups. The occlusal contacts were compared trough ANOVA and Tahame Post-test. There was a statistically significant difference (p = 0.002) between the TRIOS (M = 7.99) system and the Ineos (M = 6.78) and 3Shape D900 (M = 6.94) systems. There was also a statistically significant difference between the different chairside and InLab systems (p <0.001) in the occlusal contacts evaluation with carbon, using the ANOVA test and Tukey's post-test (Bluecam M = 7.89; ApolloDi M = 7.27; TRIOS M = 7.41; 3Shape D900 M = 6.90 and Ineos M = 4.09). A similar result was observed in the qualitative assessment of these occlusal contacts, using the Chi-Square test, in the category Excellent / Good for Bluecam systems (93.3%), ApolloDi (73.3%), TRIOS (86.7%) and 3Shape D900 (70%) and in the Deficient category, Ineos (93.3%). The Chi-Square test was also used to analyse the clinical quality of proximal contacts, using dental floss and 50% of the crowns had contact deficiency, with no contact point. Only the TRIOS system presented 75% of their crowns categorized as Excellent / Good. Within the limitations of the study, it was concluded that the Chairside systems showed better results when compared to the InLab systems in reproducing the virtual occlusal and proximal contact points in the real contacts after milling and fixing the crowns, simulating a clinical situation. Chairside systems also showed better accuracy in the quality of occlusal and proximal contacts compared to InLab systems, which, despite presenting inferior results, were also satisfactory.