One-year clinical and radiographic outcomes of immediate versus delayed placement of wide-diameter implants in the mandibular molar region

PURPOSE: This study aims to evaluate the clinical and radiographic outcomes of immediate versus delayed placement of 6–7 mm diameter implants in molar extraction sites. MATERIALS AND METHODS: In this retrospective study, 46 patients requiring single implant restoration in the mandibular molar region were enrolled and divided into two groups: Immediate placement (IP) (n = 22) received immediate implant placement with Bio-Oss grafting, while Delayed placement (DP) (n = 24) underwent delayed implantation 4 months post-extraction following Secondary intention healing. All implants were submerged for 4 months before prosthetic loading, which was performed 4–6 months after implant placement.Primary outcome measures included primary and secondary implant stability (assessed via resonance frequency analysis, implant stability quotient ISQ values), buccal bone plate width, marginal bone level (MBL) changes, and peri-implant probing depth (PPD). All outcomes were assessed at four time points: immediately after implant placement, at 3 months, 6 months, and 12 months postoperatively. RESULTS: All 46 patients completed the 1-year follow-up with no reported implant or prosthetic failures. The Immediate placement (IP) demonstrated significantly lower insertion torque (mean: 25 ± 3.5 N·cm, range: 15–35 N·cm) compared to the delayed group (DP); mean: 35 ± 4.5 N·cm, range: 25–45 N·cm) (p = 0.021). However, no significant differences were observed in secondary stability at 6 months (IP): 77.8 ± 3.5 vs. (DP): 78.6 ± 3.4, p = 0.521) or 12 months (IP): 78.7 ± 3.3 vs. (DP): 78.8 ± 3.6, p = 0.649). Buccal bone plate thickness showed no significant differences between groups at 6 months (1.8 ± 0.23 mm vs. 1.7 ± 0.17 mm, p = 0.510) or 12 months (1.7 ± 0.18 mm vs. 1.6 ± 0.12 mm, p = 0.429). Marginal bone loss at 12 months was 0.15 ± 0.06 mm in (IP) and 0.12 ± 0.04 mm in (DP), with no statistically significant difference between the groups (p = 0.478 ). PPD was similar between groups (IP: 2.3 ± 0.27 mm vs. DP: 2.5 ± 0.24 mm, p = 0.653). CONCLUSION: Immediate placement of wide-diameter implants in mandibular molar regions demonstrated a 100% survival rate and favorable clinical outcomes comparable to delayed implantation over a 1-year follow-up period. The use of Bio-Oss bone grafting in immediate implantation appears beneficial for bone preservation. These findings suggest that immediate placement of wide-diameter implants can achieve clinical outcomes equivalent to delayed protocols in selected cases.