Clinical Outcome of Abutments made of Ti, ZrO2 and PMMA—a randomized pilot study

TTYVV ePOSTER BASIC RESEARCH

Background: Different materials have been compared in several studies in order to find suitable materials for dental implants, abutments, healing abutments, and fixed dentures. In these, most researchers have focused on biological complications and have compared titanium (Ti) and zirconia (ZrO2) as material. In addition to ZrO2-based and Ti-based materials, research is increasingly being conducted on polymethylmethacrylate (PMMA) as a material for fixed dentures or healing abutments.

Aim/Hypothesis: In this pilot study, the effect of different abutments materials (Ti, ZrO2, PMMA) on marginal bone loss (MBL) one-year post-loading was compared. The hypothesis was that there is no difference in MBL.

Materials and Methods: 30 patients, randomized into 3 groups, received two-piece titanium implants in single-tooth gaps. Healing abutments made of different material (titanium, zirconia or PMMA) were placed after a submerged healing period. All groups received permanent or provisional suprastructure of the same material. At loading (baseline) and 1 year post loading, intraoral digital radiographs (Sirona D3507, Sirona Dental Systems GmbH, Bensheim, Germany) with rectangular collimation were obtained to measure the mesial and distal bone loss around each implant. All radiographs were investigated in twofold magnification for evaluability by two experienced investigators, not involved in the clinical procedure, and statistically analysed. MBL was calculated as the difference between the bone levels, where negative MBL values indicate a bone loss.

Results: The Ti group (group 1) had a mean MBL of -0.09 ± 0.33 mm, whereas the bone losses of PMMA (group 3) resulted in -0.16 ± 0.22 mm and MBL of ZrO2 (group 2) showed the highest results -0.38 ± 0.33 mm. MBL values showed differences between Ti group (group 1) and the two other groups. PMMA (group 3) showed slightly better values than ZrO2 (group 2), whereby this difference is not significant (one-factorial analysis of variance with P = 0.106 for the change from 3 to 15 months).

Conclusions and Clinical Implications: Only studies comparing Ti and Zr abutments exist. 1-year results of Hosseini et al. showed similar MBL for Ti and Zr abutments; De Albornoz et al. found minimal mean peri-implant bone level changes at 1 year. Our results showed that MBL were comparable to the results of other publications. Thus, all materials seem appropriate as healing abutments and abutments concerning MBL. Further long-term investigations are necessary prior to application of PMMA as abutment material.

Keywords: Prosthodontics, Clinical trials, Bone implant interactions, Clinical research, Abutment