Clinical comparison between crestal and subcrestal dental implants: A systematic review and meta-analysis

Statement of problem: How the performance of dental implants is related to their occlusogingival placement, crestal or subcrestal, is unclear.

Purpose: The purpose of this systematic review and meta-analysis was to evaluate marginal bone loss, implant survival rate, and peri-implant soft tissue parameters between implants placed at the crestal and subcrestal bone level.

Material and methods: Two independent reviewers searched the PubMed/MEDLINE, Embase, and Cochrane Library databases for randomized clinical trials published up to September 2020. The meta-analysis was based on the Mantel-Haenszel and the inverse variance methods (α=.05).

Results: The search identified 928 references, and 10 studies met the eligibility criteria. A total of 393 participants received 709 implants, 351 at crestal bone levels and 358 at subcrestal bone levels. Meta-analysis indicated that crestal bone level implants showed similar marginal bone loss to that seen with subcrestal bone level implants (mm) (P=.79), independent of the subcrestal level (P=.05) and healing protocol (P=.24). The bone level implant placement did not affect the implant survival rate (P=.76), keratinized tissue (mm) (P=.91), probing depth (mm) (P=.70), or plaque index (%) (P=.92).

Conclusions: The evidence suggests that both approaches of implant placement are clinically acceptable in terms of peri-implant tissue parameters and implant-supported restoration survival.