Soft tissue response to zirconia and titanium implant abutments: an in vivo within-subject comparison

Aim To compare the health of the soft tissues towards zirconia and titanium abutments in man, as observed using histological data. Material and Methods Twenty patients received two mandibular implants with either a zirconia or titanium abutment (split mouth study design, left-right randomization). After 3 similar to months soft tissue biopsies were prepared for histological evaluation. They were subjected to blind evaluation. The number of blood vessels per surface unit and an inflammation grading scale score ranging from 1 to 4 were determined. Results Paired samples from 17 patients were suitable for analysis, 3 with unsevered implant-abutment connections and 14 solely containing soft tissue. All showed a well-keratinized stratified squamous epithelium which was continuous with the barrier (junctional) epithelium that faced the abutment surface. The normal epithelial build-up could be recognized with little signs of inflammation. No statistically significant difference in tissues adjacent to zirconia and titanium abutment surfaces were seen with respect to vascular density (20.5 SD 4.4 and 20.7 SD 3.2) or inflammation grading scale scores (3.2 SD 0.7 versus 3.1 SD 0.7). Conclusion No differences in soft tissue health were seen in peri-implant mucosa adjacent to zirconia and titanium abutment surfaces.