Excess cement found on tooth-retained restorations with healthy periodontal tissues present few if any problems. The cement-retained implant restoration may be more vulnerable to the effects of cement entering the soft tissues and residual excess cement on the implant restoration when compared to a tooth. It has been hypothesized that an open/hollow abutment may provide an internal reservoir for cement.
Materials and methods: The patients included in the study were divided into two groups according to the abutment design that was used after implant placement; closed abutment group (CA) where 7 crowns were cemented on closed abutments vented abutment group (VA) where 7 crowns were cemented on vented abutments. |Re-examination was scheduled 3, 6 and 12 months after crown cementation. Periodontal assessment included Bleeding Index (BI) and Probing depth (PD). Bone height measurements were performed using cone beam computed tomography to measure the marginal bone loss.
Results: Considering different intervals of the follow-up period, the differences in BI and PD between tested groups (vented and closed abutments) were statistically non-significant (p>0.05), but there was a statistically significant increase in PD for comparison between PD at different time periods in each group after 6 months as well as from 6 months to 12 months.
After 3, 6 as well as 12 months, Group CA showed statistically significantly higher mean amounts of bone loss than Group VA.
Conclusions: (1) Vented abutments exhibit better soft tissue response and less marginal bone loss when compared to closed abutments through one year follow up. (2) Soft tissue response and marginal bone loss associated with both abutment designs were within the normal health limits after one year follow up period of the study.