Impact of splinting implant-supported crowns on the performance of adjacent posterior implants: A systematic review and meta-analysis.

Statement Of Problem: While rehabilitation with implant-supported crowns in the posterior region is widely practiced, guidance on clinical considerations when choosing between splinted or nonsplinted implant-supported crowns is limited.

Purpose: The purpose of this systematic review with meta-analysis was to assess whether adjacent implants with internal connections in the posterior region should be treated with splinted or nonsplinted crowns.

Material And Methods: The systematic review was registered on the prospective register of systematic reviews (PROSPERO) under the code, CRD42021248525. Two authors searched 4 electronic databases (PubMed, Cochrane Library, Scopus, and Web of Science) independently for articles published up to December 2023. Additionally, a hand search was conducted in the nonpeer-reviewed literature and the reference lists of included articles. Only clinical studies comparing splinted and nonsplinted hexagonal or conical internal connection adjacent implants in the posterior region were considered. A single-arm meta-analysis was conducted using RevMan. Risk of bias and quality were assessed using the Cochrane Collaboration's Tool for Assessing Risk and the Newcastle-Ottawa scale.

Results: Qualitative synthesis included 17 studies, and quantitative synthesis involved 13 studies. A total of 2085 implants (1244 splinted and 841 nonsplinted) were inserted in 1027 participants, with observation times ranging from 5 months to 16 years. Thirteen studies related the type of crown retention (cemented or screw-retained). Only 2 studies related annual bone loss results considering the type of crown retention, but whether they were splinted or nonsplinted crowns and significant differences were not specified. The meta-analysis revealed no statistical differences between splinted and nonsplinted implants for biological complications (P=.95, I=0%). However, the nonsplinted implants exhibited significantly more mechanical complications than the splinted implants (P<.001, I=1%, RR 0.37; 95% IC [0.26-0.54]). The studies included demonstrated a low risk of bias and were of good quality.

Conclusions: Splinting was not found to affect the incidence of biological complications in posterior adjacent implants. However, more mechanical complications occurred in nonsplinted crowns than splinted ones.