Comparison of surface roughness of two single shaded resin composites after pH cycling and simulated teeth brushing - an in-vitro study

Background the study aimed to examine and compare the surface roughness of two single-shaded resin composites Omnichroma and Charisma Topaz One after pH cycling and simulated toothbrushing. Methods Forty disc-shaped resin composite specimens were fabricated using split Teflon mold and divided into two main groups (C1: Omnichroma, C2: Charisma Topaz One) according to the two single shaded resin composite utilized (n = 20). finishing and polishing of top surfaces of specimens was done using a multi-step Sof-Lex system. Baseline surface roughness (R0) was measured for each group using a 3D non-contact optical profilometer device. Then the specimens were immersed in demineralization-remineralization solutions at room temperature to mimic pH cycling model. Followed by surface roughness measurement (R1) were assessed again for the prepared specimens. All specimens were then subjected to simulated toothbrushing. then surface roughness measurement was taken (R2). Results Charisma Topaz One demonstrated higher initial surface roughness values compared to Omnichroma at baseline (*p* < 0.0001). Following pH cycling, both materials exhibited similar surface roughness values with no statistically significant difference between the two tested materials. Additional simulated tooth brushing was deemed to show increase in surface roughness values with no significant difference between them. Conclusions Initial polishing of single shaded Nanofilled Omnichroma provided superior smoothness, although single shaded Nanohybrid Charisma Topaz One exhibited lower values. Repeated pH cycling and simulating tooth brushing markedly influences surface roughness of both Omnichroma and Charisma Topaz One.