Effect of Implant Vertical Position, Design, and Surgical Characteristics on Mucosal Vertical Dimension: A Meta-Analysis of Animal Studies

Purpose: The aim of this study was to investigate the effect of implant and surgical characteristics on the mucosal vertical dimension components. Mucosal vertical dimension consists of the sulcular epithelium and the supracrestal tissue attachment, which can be clinically measured from the gingival margin to the bone-to-implant contact. Connective tissue attachment is measured from the apical border of attached epithelium to the first bone-to-implant contact, while epithelial vertical dimension is measured from the mucosal margin to the apical border of attached epithelium. Materials and Methods: An electronic and manual search for relevant articles published from January 1980 to May 2019 was performed. Animal studies of ≥ 10 implants followed by histometric analysis were included. Quality assessment was performed using the ARRIVE guidelines, and risk of bias assessment was performed using SYRCLE guidelines. Subgroup meta-analysis was performed to analyze the influence of different surgical approaches and implant design. Results: A total of 38 articles were included. The mean value and corresponding standard error of mucosal vertical dimension, supracrestal tissue attachment, connective tissue attachment, and epithelial vertical dimension were 3.39 ± 0.07 mm, 2.9 ± 0.12 mm, 1.35 ± 0.04 mm, and 2.0 ± 0.06 mm, respectively. Supracrestal and subcrestal bone-level implants had significantly higher mucosal vertical dimension than equicrestal bone-level implants. Platform-switching implants demonstrated significantly lower mucosal vertical dimension compared with non–platform-switching implants. Conclusion: Within its limitations, this review showed that equicrestal implants had a smaller mucosal vertical dimension than subcrestal and supracrestal implants, and platform-switching implants possessed a smaller mucosal vertical dimension. Keywords: dental implant, dental implant-abutment design, dental implantation, evidence-based dentistry