Biological width establishment around dental implants is influenced by abutment height irrespective of vertical mucosal thickness: A cluster randomized controlled trial.

Abstract

Prosthetic abutment height and peri-implant mucosal thickness are considered factors that influence marginal bone remodeling during biological width establishment around dental implants. However, no clinical studies have evaluated their simultaneous effect on marginal bone loss (MBL). This study analyzes the influence of abutment height on MBL around implants surrounded by both thin and thick mucosa up to 12months after prosthetic loading. Seventy platform-switched implants with internal hex were placed equicrestally in two groups of patients with different vertical mucosal thickness: thin (≤2.0mm) and thick mucosa (>2.0mm). After three months of submerged healing, prosthetic abutments with a height of 1mm (short) or 3mm (long) were randomly assigned for single crown screwed restoration in both groups. MBL was evaluated on radiographs taken at implant placement (T0 ), restoration delivery (T1 ), and after 6months (T2 ) and 12months (T3 ) of loading. After 12months of loading, 66 implants were functioning (two dropouts, two failures), resulting in a 97% survival rate. Compared with T0 , mean MBL at T3 ranged between 0.59 and 0.80mm in short abutment groups and between 0.28 and 0.37mm in long abutment groups. Differences resulted statistically significant, irrespective of vertical peri-implant mucosal thickness. The MBL pattern over time showed the greatest amount of bone resorption in the first 6months after loading, particularly around implants with short abutments. Platform-switched implants restored with short abutments present greater marginal bone loss than identical implants with long abutments, without significant peri-implant mucosal thickness effects.