Impact of abutment geometry on early implant marginal bone loss. A double-blind, randomized, 6-month clinical trial

Objectives The objective of this study was to analyze the impact of the abutment width on early marginal bone loss (MBL). Material and Methods A balanced, randomized, double-blind clinical trial with two parallel experimental arms was conducted without a control group. The arms were cylindrical abutment and concave abutment. Eighty hexagonal internal connection implants, each with a diameter of 4 x 10 mm, were placed in healed mature bone. The main variable was the peri-implant tissue stability, which was measured as MBL at 8 weeks and 6 months. Results The final sample consisted of 77 implants that were placed in 25 patients. 38 (49.4%) were placed using the cylindrical abutment, and the other 39 (50.6%) were placed using the concave abutment. The early global MBL of -0.6 +/- 0.7 mm in the cylindrical abutment group was significantly higher than it was in the concave abutment group, in which the early global MBL was -0.4 +/- 0.6 mm (p = .030). The estimated effect size (ES) was negative for the cylindrical abutment (ES = -1.3730, CI -2.5919 to -0.1327; t-value = -2.4893; p = .0139), therefore implying a loss of mean bone level, and it was positive for the concave abutment (ES = 2.8231; CI: 1.4379 to 4.2083; t-value = 4.0957; p = .0002), therefore implying an increase in the average bone level. Conclusions The concave abutments presented significantly less early MBL at 6 months post-loading than classical cylindrical abutments did.

Automated summary

This study analyzed the impact of abutment width on early marginal bone loss. The results showed that concave abutments had significantly less early bone loss at 6 months post-loading compared to classical cylindrical abutments.