The peri-implant soft tissue reactions and cytokine expressions around different abutment materials : randomized controlled clinical trial

Abstract

Objectives : Stable peri-implant soft tissue around transmucosal zone are the crucial factor for long-term success and survival of dental implants. The aim of this study was to evaluate the expression of proinflammatory cytokines and chemokine around 3 types of abutment materials : titanium (Ti), zirconium oxide (Zr) and gold alloy (Au).

Methodology : 15 dental implants were enrolled in this study. Clinical parameters and peri-implant crevicular fluid (PICF) were collected at weeks 4, 6, 8 and 10. The soft tissue characteristics were demonstrated using plaque assessment score and mucosal condition score. Cytokine levels were determined by enzyme-linked immunosorbent assay (ELISA). Nonparametric statistics were used to describe the comparison of abutment materials and cytokine levels.

Results and Discussion : At 4,6 and 8-week of healing period, gold alloy abutments induced the highest level of IL-1beta and IL-6. In pairwise test, there were significant differences in IL-1beta at week 4 and 6 between Au and Zr abutment p-value 0.024 and 0.032, respectively. For Au and Ti abutment, statistical significances were observed at week 4, 6 and 8 p-value 0.015, 0.022 and 0.033, respectively. The analyses compared values of weeks 4, 6, 8 and 10 showed there were no significant differences in IL-8 between abutment materials. The average surface roughness of abutment material was reported similar roughness. However, different materials exhibited different plaque and mucosal condition score. These findings supported the implant abutment materials have an influence on the immune response.

Conclusion : Gold alloy abutment induced higher levels of IL-1beta and IL-6 in PICF when compared with titanium and zirconium oxide abutment at weeks 4. 6 and 8 whereas no significant differences in the expression of IL-8 all time points. Higher plaque score and mucosal tissue conditions were reported in gold alloy abutment. Therefore, strict oral hygeine instructions should be given to patients when using gold alloy abutment especially in early healing period.