Força máxima de carregamento de facetas oclusais minimamente invasivas confeccionadas por CAD/CAM

Abstract

Objective: The aims of this study were evaluate and compare the maximum load strength of the following materials: nanoceramic resin, lithium dissilicate ceramic and zirconium dioxide-reinforced lithium silicate ceramic when used as occlusal veneers in thicknesses recommended by the manufacturer and/or reduced to 0.6 mm, and the occurrence of fracture and fracture types. Materials and Method: Fifty six human molars extracted were randomly divided into 7 groups according to the material and thickness: Control group; L15 and L06 groups (Lava Ultimate), E15 and E06 (e.max CAD) and S10 and S06 (Suprinity). Each material was used in two thicknesses, the minimum thickness recommended by the manufacturer and 0.6mm. All restorations were made using CAD/CAM CEREC system. After milling, all samples were treated according to manufacturer’s recommendations and etched with hydrofluoric acid and silane when indicated. For teeth etching it was used 37% phosphoric acid for 15 seconds selectively enamel, washed for 30 seconds with water and dried with compressed air. The adhesive used was Single Bond Universal, applied actively for 20 seconds. For the cementation was used the dual cement Relyx Ultimate. Results: There was a statistically significant difference in the relationship between the material used and the maximum load strength. There was no significant difference between material and thickness within the groups. The largest recorded charging load average was 3428.25 N at Control Group however without statistically difference from the L15 group 2995.75 N. E15 groups, E06, S10 and S06 showed no statistically significant difference, the lowest average was recorded in group S06 1330.68 N. Conclusions: Within the limitations of this in vitro study, it is possible to concluded that material interfere in the maximum power load in occlusal veneers, however reducing the thickness of these materials does not affect the maximum force recorded charging, all materials recorded loading force greater than that recorded in natural occlusion.