Depth of mucosal tunnel in peri-implant health during 12-month follow-up in patients with controlled periodontitis

Abstract

Background: The association between thickness of peri-implant mucosa, known as mucosal tunnel (MT) and related clinical parameters in bone-level implants has not been investigated. Methods: Posterior implants, in patients with controlled periodontitis, were evaluated at different time intervals: during uncovering surgery (T0), 2-month after uncovering surgery (T2M) and 12-month after placement (T12M). Clinical parameters including vertical soft tissue height (VSTH), MT, tooth-implant discrepancy of bone level (DBL), pocket depth (PD), peri-implant marginal bone loss (MBL), emergence profile and emergence angle (EA) were collected, and the correlation were assessed at different time points. Results: Forty-two patients with 60 implants were recruited, and 81.7% of the patients were Stage III-IV, Grade B–C generalized periodontitis. MT presented no significant difference in PD, VSTH, and MBL. Periodontitis Grade C and absence of bone regeneration were significant predictors for deep MT (>3 mm), and 5.850 less EA at mesial side of implants (p = 0.02).The regression of analysis implied the increase of DBL 1 mm would cause 0.26 mm deeper MT, 1.7 times higher risk of having deep MT (p = 0.041; OR = 1.731; 95% CI:1.02–2.93) and 2.1 times higher risk of having circumferential PD > 4 mm (p = 0.019; OR = 2.1; 95% CI:1.13–3.92). Conclusions: In bone-level implants, a correlation between MT and clinical parameters at 12-month follow-up was not found. However, history of periodontitis Grade C, absence of bone regeneration and tooth-implant discrepancy of bone level might define the depth of MT. Additionally, the depth of MT played a critical role in determining restorative design.