Surface roughness and bacterial adhesion on composite materials: an in vitro comparative evaluation

Introduction and Aim: Despite being popular, composite materials frequently degrade, and cause secondary caries in the oral cavity. Studies suggest that surface characteristics, particularly surface roughness, can impact the functionality, durability, and biofilm formation of these materials. This study was carried out to evaluate and compare the surface roughness of nano-ceramic restorative and bulk-fill flowable composite materials and their bacterial adhesion properties using Streptococcus mutans. Materials and Methods: 16 disks of each composite type, Ceram x SphereTEC one universal nano-ceramic restorative material and SDR flow plus bulk-fill flowable material were fabricated and grouped as A and B, respectively. 2D surface roughness of the samples were recorded using Contact Profilometer. For bacterial adhesion test, samples were incubated in a culture of S. mutans overnight. Adhered bacteria were determined by spread plate technique, colonies were enumerated and reported as CFU/mL. Kolmogorov-Smirnov and Shapiro-Wilk tests helped determine normality distribution of surface roughness, and statistical significance was analysed using Independent-samples t test. Bacterial adhesion was analysed using Mann-Whitney U test. Results: Surface roughness values were found to be normally distributed, and the difference between the two groups was noted to be statistically significant (p<0.05). However, there was no statistical difference between bacterial adhesion amongst the two materials (p>0.05). Conclusion: Surface roughness value of the nano-ceramic restorative material was lower than that of bulk-fill flowable resin material albeit, the two composites did not show a significant difference in terms of bacterial adherence.