Early survival of single-tooth implants in the esthetic zone may be predictable despite timing of implant placement...

The authors used MEDLINE, EMBASE, and CENTRAL (Cochrane Central Register of Controlled Trials) databases to locate studies for this systematic review (SR). For studies to be eligible for this SR, all had to evaluate single-implant restorations with a follow-up of at least 1 year after implant loading. A total of 19 prospective studies met inclusion and exclusion criteria. Fifteen studies provided implant survival data (499 patient/509 implants), whereas 5 studies provided radiographic marginal bone height data (52 patients/52 implants). The analysis included studies with patients with single anterior or premolar,maxillary or mandibular edentulous sites bounded by anterior and posterior neighboring teeth. Meta-analyses of prospective trials (randomized-controlled trials, clinical trials, cohort studies, case series) reported loaded implant survival with one-year or more than one-year follow-up. Meta-analysis of prospective trials reporting marginal bone loss with one-year follow-up was also reported.

The key interventions were the timing of implant placement following extraction and the timing of implant loading after implant placement. Comparisons following greater than one-year follow-up were made between implants with immediate placement with immediate loading, immediate/early placement with conventional loading, conventional placement with immediate/early loading, or conventional placement with conventional loading.

The main outcome was implant survival. Radiographically determined peri-implant bone level change was also reported. Meta-analyses were completed using studies that reported one-year implant survival data (15 studies) and more than one-year implant survival data (11 studies). One-year marginal bone level data were analyzed for implants treated conventionally (5 studies). For survival and marginal bone levels, weighted rates and random effects models were used to calculate overall effects of the included studies. For greater than one-year follow-up, survival data were stratified by intervention type. Results were weighted for study size and stratified based upon timing of implant placement and loading. Esthetics, and patient satisfaction, and complications were reported, but heterogeneity of study design and reported outcomes excluded the results from meta-analysis.

Approximately two-thirds of patients received implants in healed edentulous sites. Survival of single-tooth implants one year in function was 95.5% [95% CI: 93.0-97.1]. Meta-analysis identified no difference in survival rate at one year when the results were weighted for study size and stratified based upon timing of implant placement and loading. Survival of single-tooth implants more than one year in function ranged from 92.4% [95% CI: 84.4-96.4] for conventional placement with immediate loading to 97.5% [95% CI: 88.3-99.5] for immediate placement with immediate loading. The third meta-analysis identified 0.20-mm [95% CI:0.034-0.36] marginal bone loss for implants one year in function. Qualitative interpretation of other esthetic, patient satisfaction, and complication outcomes revealed no difference in immediate, early, or conventional therapy approaches.

The authors concluded that implant-supported single-tooth replacement in the aesthetic zone with adjacent natural teeth can lead to short-term, favorable outcomes with regard to implant survival and marginal bone level change with early/immediate or conventional surgical placement and loading strategies.