Fig 5. Biofilm formation, assessed by MTT assay.

Data are shown as means +/- 1 SD. In each study, different superscript letters highlight significant differences between groups (p<0.05). A: in vitro data showed that laser-modified surfaces were less colonized than grit-blasted ones. Machined surfaces showed intermediate values of biofilm formation, non-significantly different from grit-blasted or laser-treated surfaces. Enamel reference surfaces showed similar biofilm formation as grit-blasted surfaces. B: machined and laser-treated surfaces were less colonized than grit-blasted ones, while no significant differences were identified between machined and laser-treated surfaces.