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.