Bacterial Colonization and Soft Tissue Health around Titanium and Zirconia

Methods: Twenty edentulous subjects received 2 endosseous mandibular implants. They were fitted with either a ZrO2 or a Ti abutment with similar roughness (non-submerged implant placement, within-subject comparison, left-right randomisation). Permucosal bacterial sampling and the assessment of probing pocket depth (PPD), recession (REC) and bleeding on probing (BOP) were performed at 2 weeks and 3 months post-surgery. Wilcoxon matched-pairs, sign-rank test and paired t-tests were applied to test differences in the counts of 7 marker bacteria and the clinical parameters that were associated with the ZrO2 and Ti abutments, at the 2 observation times.

Results: ZrO2 and Ti abutments harbored similar counts of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythensis, Peptostreptococcus micros, Fusobacterium nucleatum and Treponema denticola at 2 weeks and 3 months. Healthy clinical conditions were seen around both ZrO2 and Ti abutments at all times, without significant differences in the clinical parameters of peri-implant soft tissue health.

Conclusions: No marked difference in early bacterial colonization, nor a clinically discernable difference in the health of permucosal soft tissues adjacent to ZrO2 and Ti abutment surfaces could be demonstrated. Zirconia abutment surfaces are not less prone to early bacterial colonization compared to titanium abutments in vivo. From a clinical perspective they appear to elicit a comparable soft tissue response.

Source of funding: This research was made possible by a grant from Astra Zeneca (Mölndal, Sweden), who also provided the experimental abutments without costs.