Thoma DS, et al. - Authors evaluated the impact of veneering of the submucosal part of zirconia abutments and the type of retention (cemented vs screw-retained) on clinical, microbiological, and histological outcomes of single-tooth implant crowns. Findings did not suggest any negative impact of submucosal veneering of zirconia abutments on the health of the peri-implant tissues. Though, a clinical and histological trend to higher levels of inflammation was not demonstrated by the cemented groups. low bacterial counts and a similar distribution in between the groups was demonstrated by the microbiological test except for two species (Tannerella forsythia and Peptostreptococcus micros) that were found in higher counts in the cemented groups at 6 months.