Dental implant treatment for two adjacent missing teeth in the esthetic region: A systematic review and 10-year results of a prospective comparative pilot study.

Abstract

The aim of the systematic review was to compare studies on implant-supported two-unit cantilever crowns with two adjacent implant-supported crowns in the anterior region. The second aim was to assess in a 10-year prospective comparative pilot study, hard and soft peri-implant tissue changes in patients with a missing central and adjacent lateral upper incisor, treated with either an implant-supported two-unit cantilever crown or two single implant-supported crowns. Medline, Embase, and the Cochrane Central Register of Controlled Trials were searched (last search March 1, 2023). Inclusion criteria were studies reporting outcomes of two missing adjacent teeth in the esthetic region and treated with a single implant-supported two-unit cantilever fixed dental prosthesis, or with two solitary implant-supported crowns. Outcome measures assessed included implant survival (primary), changes in marginal bone and gingiva level, restoration survival, subjective and objective esthetic scores, papilla volume, mid-facial marginal mucosa level, probing depth, bleeding on probing, and biological and technical complications with ≥1-year follow-up. In addition, in a 10-year pilot study, the same outcome measures were assessed of five patients with a single implant-supported two-unit cantilever crown and compared with five patients with two adjacent single implant-supported crowns in the esthetic zone. Nine articles with 11 study groups were found eligible for data extraction. Meta-analyses of implant survival rates were 96.9% (mean follow-up 3.4 ± 1.4 years) for the implant-cantilever treatment and 97.6% (mean follow-up 3.0 ± 1.8 years) for the adjacent implants treatment (p = .79). In the 10-year comparative pilot study, no clinically relevant changes in hard and soft peri-implant tissue levels occurred in both groups. Patient satisfaction was also high in both groups. Single implant-supported two-unit crowns can be a viable alternative to the placement of two adjacent single implant crowns in the esthetic zone.