Influence of thermocycling and coffee immersion on surface roughness and bacterial adherence of additively manufactured permanent resin based materials

This in vitro study assessed the effect of thermocycling and thermocycling followed by coffee immersion on surface roughness and bacterial adherence of three additive manufactured permanent resin based materials. Disc specimens of VarseoSmile TriniQ, SprintRay Crown Resin, and Tera Harz C&B TC-80DP were allocated to baseline, thermocycling, or thermocycling followed by coffee immersion. Surface roughness was measured by optical profilometry and reported as Ra. After artificial saliva conditioning, adhesion of Streptococcus mutans and Streptococcus sanguinis was quantified as log10(CFU/mm²). Surface roughness was evaluated using two-way ANOVA, whereas bacterial adhesion data were evaluated using three-way ANOVA (α = .05). Ra values ranged from 0.06 ± 0.02 to 0.18 ± 0.04 µm. Material type and aging condition significantly affected surface roughness (P<.001), whereas their interaction was not significant (P=.360). Bacterial adhesion ranged from 2.95 ± 0.18 to 4.20 ± 0.28 log (CFU/mm²) and differed significantly according to material type, aging protocol, and bacterial species (P<.001). Streptococcus mutans showed higher adhesion than Streptococcus sanguinis. Surface roughness was positively associated with bacterial adhesion for both species (P<.001). Surface roughness and bacterial adherence increased after thermocycling and were highest after thermocycling followed by coffee condition.