Effect of Primary Stability and Soft- and Hard-Tissue Thickness on Marginal Bone Loss: A Prospective Pilot Study

Objective: To compare prospectively the effect of different insertion torques (ITs) on marginal bone stability and study the effect of soft-tissue and buccal bone thickness as confounding factors while using a 3-dimensional radiographic evaluation. Materials and Methods: Thirty-nine implants were placed in 22 patients. IT, soft-tissue thickness, and buccal bone thickness were recorded at implant placement. Marginal bone loss was evaluated on individualized periapical radiographs and cone-beam computed tomography at 1 year after loading. Results: Three groups of implants emerged based on their IT: group I (<30 Ncm), group II (between 30-45 Ncm), and group III (>45 Ncm). Soft-tissue thickness was <= 2 mm in 10 implants (25.6% thin biotype) and more than 2 mm in 29 implants (74.4% thick biotype). No significant difference in marginal bone loss was found for different IT and different soft-tissue thickness. A significant correlation was found between initial buccal bone thickness (>= 2 mm or <2 mm) and marginal bone loss at 1 year. Conclusions: IT and mucosal tissue thickness did not influence marginal bone loss. Buccal bone thickness of >= 2 mm was associated with a minimal marginal bone remodeling.