Effect of the implant apical exposure and coverage < or ≥ 2mm bone graft on transcrestal sinus floor elevation: a 1- to 7-year retrospective cohort study.

Abstract

This study aimed to analyze the effect of the apex coverage by the bone graft, including exposure and coverage less than or greater than 2mm on implant survival rate and peri-implant bone and soft tissue remodeling. A total of 264 implants in 180 patients who had undergone transcrestal sinus floor elevation (TSFE) with simultaneous implant placement were included in this retrospective cohort study. Radiographic assessment was used to categorize the implants into three groups based on apical implant bone height (ABH): ≤ 0mm, < 2mm, or ≥ 2mm. The implant survival rate, peri-implant marginal bone loss (MBL) during short-term (1-3years) and mid- to long-term (4-7years) follow-up, and clinical parameters were used to evaluate the effect of implant apex coverage after TSFE. Group 1 had 56 implants (ABH ≤ 0mm), group 2 had 123 implants (ABH > 0mm, but < 2mm), and group 3 had 85 implants (ABH ≥ 2mm). There was no significant difference in the implant survival rate between groups 2 and 3 compared to group 1 (p = 0.646, p = 0.824, respectively). The MBL during short-term and mid- to long-term follow-up indicated that apex coverage could not be considered a risk factor. Furthermore, apex coverage did not have a significant effect on other clinical parameters. Despite limitations, our study found that implant apex coverage by the bone graft, including exposure and coverage levels less than or greater than 2mm, did not significantly affect implant survival, short-term or mid- to long-term MBL, or peri-implant soft tissue outcomes. Based on 1- to 7-year data, the study suggests that implant apical exposure and coverage levels of less than or greater than 2mm bone graft are both valid options for TSFE cases.