Virtual bone-implant contact surface effect on implant stability in fresh extraction and healed sites: a pilot randomised clinical trial

This study aimed to assess the effect of bone-implant contact surface area (BIC) on implant stability at fresh extraction sites without grafting, at simultaneous grafting, and at healed implant sites using a novel digital workflow that combines preoperative CBCT segmentation with postoperative intraoral scanning. A randomized controlled trial was conducted in 30 patients requiring dental implants in the upper premolar or molar regions. The patients were divided into three groups. Group I received immediate implant placement with grafts, Group II received immediate implant placement without grafts, and Group III followed the standard implant placement protocol for healed edentulous regions. All implants were placed by the same surgeon using the same implant system and the standard surgical protocol recommended by the manufacturer. In Group I, the residual gap was filled with a bone graft and covered with a membrane after implant placement. BIC and virtual non-contact surfaces (BINC) were calculated using digital registration. All results were compared among the groups based on insertion torque and ISQ values. The final analysis included 28 patients (10 males and 18 females). Group III showed better primary stability and insertion torque than the immediate placement groups (P = 0.014 and P = 0.007, respectively). There was no statistically significant difference between the implants placed Group I and Group II in terms of the insertion torque, or ISQ. The intraoperative ISQ value and the ISQ-60 days were strongly correlated with BIC only in Group II (r = 0.58, P = 0.05 and r = 0.62, P = 0.03, respectively). Group I and Group II lead to similar results regarding primary stability. Group III presented greater stability values. BIC served as a meaningful indicator of early mechanical stability in Group II.