Is an internal tapered connection more efficient than an internal nontapered connection? A systematic review and meta-analysis.

STATEMENT OF PROBLEM: The internal connection is a widely used implant-abutment connection. However, a meta-analysis comparing the internal tapered and nontapered connection systems is lacking. PURPOSE: The purpose of this systematic review and meta-analysis was to assess whether the internal tapered connection performs better than the internal nontapered connection in terms of implant survival, marginal bone loss, probing depths, and complications. MATERIAL AND METHODS: The following specific question was formulated based on the Population, Intervention, Control, and Outcome (PICO) model: Do patients receiving internal tapered connection implants show better prognosis than those receiving the internal nontapered connection in terms of implant survival, marginal bone loss, probing depths, and complications? An electronic systematic literature search was conducted in the Cochrane Library databases, MEDLINE (PubMed), and Embase for relevant studies published in English without time restrictions. A manual search was also conducted. In vivo randomized controlled trials (RCTs) and prospective cohort studies were included. RESULTS: A total of 592 studies were collected from the electronic and manual searches. After independent screening by 2 reviewers, 5 RCTs and 2 prospective cohort studies were included. No significant difference was observed in implant survival rates (P=.47; RR: 1.01; 95% CI: 0.98, 1.05). Regarding marginal bone loss, the internal tapered connection presented better results than the nontapered connection (P=.003; MD: -0.43 mm; 95% CI: -0.73, -0.14). The internal tapered connection also exhibited lower probing depths than the nontapered one (P=.002; MD: -0.24 mm; 95% CI: -0.39, -0.09). No significant difference was observed in complication rates (P=.47; RR: 1.21; 95% CI: 0.72, 2.04). CONCLUSIONS: Within the limitations of this systematic review and meta-analysis, the internal tapered connection and nontapered connection were comparable in terms of implant survival rates and complication rates. In contrast to the internal nontapered connection, marginal bone loss and probing depths in the tapered connection were significantly lower.