Effect of implant loading protocols and associated factors on the success rate of implant therapy: A retrospective clinical study.

Statement Of Problem: Although immediate implant loading has shown promising clinical results and high survival rates, an increased risk of implant failure and complications has been reported. Achieving consistently predictable outcomes with this approach remains a challenge, but evidence-based guidelines to assist in selecting suitable patients are lacking.

Purpose: The purpose of this retrospective clinical study was to investigate the success rate, survival rate, and complications of immediate implant loading compared with early and delayed loading. Also, it sought to identify the potential risk factors of immediate implant loading.

Material And Methods: Dental records for dental implants that were surgically placed at 1 center between January 2016 and October 2021 were reviewed for different loading protocols. Time from surgical placement to load was calculated, and the implants were divided into 3 groups: immediate (IL: <3 weeks), early (EL: 3 weeks to 3 months), and delayed (DL: >3 months). Patient, procedural, and restorative parameters were also recorded. Adverse events reported were implant failure and mechanical and biological complications, and the incident rates per 100 person-years (100 PY) for each adverse event were calculated. The Kaplan-Meier and Cox Proportional Hazards models with time to event approach were stratified by time-to-load (unit of analysis: the implant). Five-year survival rates were evaluated with Kaplan-Meier survival estimates. All statistical analyses were completed with a statistical software program (α=.05).

Results: A total of 258 implants (20.1%) were in the IL group, 24 implants (1.9%) in the EL group, and 985 implants (76.8%) in the DL group. The incident rate of any adverse event was 3-fold more among implants in the IL group and EL groups as compared with the DL group (21.0/100 PY, 19/100 PY, 5.8/100 PY, respectively). Immediate implant loading was a significant predictor of implant failure (IL, HR: 30.94; 95% CI: 8.23-116.36, P=.001), failure to osseointegrate (IL, HR: 215.66; 95% CI: 7.17.98-2598, P=.001), loss of osseointegration (IL, HR: 23.77; 95% CI: 6.32-89.48, P=.001), any mechanical complications (IL, HR: 0.32; 95% CI: 0.11-0.93, P=.036), and peri-implantitis (IL, HR: 17.02; 95% CI: 1.54-17.02, P=.008). The 5-year survival rates of IL versus DL for any implant failure were 60% versus 99% and for peri-implantitis were 91% versus 99%. Diabetes and moderate periodontitis were associated with increased implant failure in the IL group.

Conclusions: Immediate loading was a significant predictor of implant failure, mechanical complication, and peri-implantitis. Diabetes and moderate periodontitis might be risk factors with immediate loading.