In Vitro Comparison of Surface Characteristics and Bacterial Adhesion in Composite Resin-Based Materials for Additive, Subtractive, and Conventional Manufacturing.

Purpose: This study aims to compare the surface roughness (SR), contact angle (CA), surface free energy (SFE), and bacterial adhesion of resin-based materials used in additive, subtractive, and conventional manufacturing techniques.

Materials and methods: This study involved four groups of 23 specimens: Indirect conventional resin composite (ICRC), subtractively manufactured resin composite (SMRC), additively manufactured resin composite (AMRC), and soda-lime-silica glass (SLSG). One specimen per group was analyzed by Energy Dispersive X-ray Spectroscopy (EDS) before polishing. Following the polishing procedure, SR, CA, and SFE were measured. The sterilized specimens were divided into two subgroups for Streptococcus mutans and Streptococcus mitis adhesion. One randomly selected specimen from each group was also reserved for visualization of bacterial adhesion using Scanning Electron Microscopy (SEM), and bacterial adhesion was quantified in the remaining specimens (n=10). Data for SR, CA, SFE, and bacterial adhesion were analyzed using one-way ANOVA, Tukey post-hoc tests, and Pearson correlation (α = .05).

Results: Among the resin groups, the ICRC group had the lowest SR values (P < .001). The higher CA was observed in the SMRC group than AMRC (P = .016). AMRC displayed significantly lower S. mitis adhesion compared to ICRC and SMRC (P < .001 and P = .003, respectively). A positive correlation was found between SR and S.mutans adhesion (R = .455, P < .003).

Conclusion: Resin materials designed for different manufacturing techniques exhibited diverse surface characteristics. Nevertheless, the 3D printable permanent resin demonstrated comparable S. mutans adhesion to that of ICRC and SMRC.