THE INFLUENCE OF ACIDIC BUFFER AND MECHANICAL BRUSHING ON THE WEIGHT LOSS AND SURFACE ROUGHNESS OF THREE DIFFERENT CAD-CAM MATERIALS

Aim of the work was to investigate the effect of pH media and the influence of the mechanical tooth brushing on the weight loss and surface roughness (Ra) of zirconia-reinforced lithium silicate glass ceramic, hybrid ceramic material and composite material.
Materials & Methods: Three types of dental materials were selected. One Composite resin material (Cerasmart), Lithium silicate glass ceramic with 10% Zirconia (Celtra Duo) and one hybrid ceramic (Vita Enamic). Eighty one disc shaped specimens (2mm in height and 12 mm in diameter) were fabricated from three different CAD/CAM materials then divided into three groups of twenty seven specimens each (n = 27) based on the treatments received. Group I Twenty seven specimens 9 from each material, recieve no treatment and were weighted examined by optical microscpe for surface topogrphy. Group II, Twenty seven specimens 9 from each material were stored in acidic buffer for168 hours then weighted. Group III, Twenty seven specimens 9 from each material were subjected to mechanical brushining and examined by optical microscpe (for quantity and quality of surface roughness). The raw data were obtained from different tests and analyzed. T test and One-way ANOVA were conducted to compare the effect of the acidic buffer storage period and mechanical brushing on the weight loss and surface roughness respectively .
Resuts: Comparison between weight loss before and after acidic buffer storage in the three groups using ANOVA analysis test showed that there was no significant difference between the three groups regarding to weight loss (0.05). The weight loss of Cerasmart group was heigher than the other two groups and there was no significant difference in surface roughness among the tested groups following 50,000 brushing cycles. The Vita Enamic materials showed lower surface roughness mean value compared to surface roughness value of Celtra Duo and Cerasmart material .
Conclusions: Within the limitations of the present study, there was no significant difference in both weight loss and surface roughness of tested materials after 168 hours storage in acidic buffer and Simulated 5 years of brushing but Cerasmart composite has the highest weight loss and surface roughness