A prospective randomized split-mouth trial comparing immediate versus early anterior implant placement with customized healing abutments: 12-month marginal bone loss, stability, and esthetic outcome

Abstract

Objectives To compare 12-month marginal bone loss (MBL) between immediate implant placement (IIP) and early implant placement (EIP) in the anterior region. Secondary objectives included the evaluation of implant stability (ISQ), esthetic outcomes (PES–WES), and peri-implant health (probing depth and bleeding index) when using customized healing abutments. Methods A prospective, randomized, split-mouth clinical trial was conducted involving 12 patients, with a total of 24 implant sites. The protocol was approved by the institutional review board (IRB2023-H0113D-P-0494), registered at ClinicalTrials.gov (NCT0698551). Each patient received one IIP and one contralateral EIP via fully guided surgery. Chairside-fabricated customized healing abutments were utilized, and definitive restorations were delivered at 3 months. Outcomes were recorded at 3, 6, and 12 months. MBL was assessed via standardized CBCT, implant stability via resonance-frequency analysis, and esthetics through Pink/White Esthetic Scores. Mixed-effects models were used for statistical analysis (α = 0.05). Results IIP demonstrated significantly lower early MBL at 3 months (mean difference: −0.30 mm, 95% CI: −0.52 to −0.08; p = 0.012) and 6 months (mean difference: −0.22 mm, 95% CI: −0.39 to −0.05; p = 0.016), and higher ISQ at 3 months (mean difference: 2.49, 95% CI: 0.49–4.49; p = 0.017) compared to EIP. However, no significant differences were observed in MBL (mean difference: −0.01 mm, 95% CI: −0.08 to 0.06; p = 0.618) or ISQ (mean difference: 0.20, 95% CI: −1.62 to 2.02; p = 0.823) at the 12-month primary endpoint. Regarding esthetics, total PES favored IIP at 6 months (mean difference: 2.09, 95% CI: 1.48–2.70; p < 0.001) and 12 months (mean difference: 1.50, 95% CI: 0.92–2.08; p < 0.001). WES was similar at 6 months (mean difference: 0.42, 95% CI: −0.31 to 1.15; p = 0.234) but favored IIP at 12 months (mean difference: 1.00, 95% CI: 0.50–1.50; p = 0.002). Peri-implant health parameters improved over time in both groups with no implant losses. Conclusions When combined with guided protocols and customized healing abutments, IIP and EIP yield comparable 12-month marginal bone outcomes. IIP provides an advantage in accelerated early stability and superior soft-tissue esthetic scores (PES) compared to EIP. The clinically meaningful esthetic advantages of IIP support its preferential use in the anterior zone when anatomical conditions permit.