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

Abstract

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. 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. 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 (>3mm), and 5.850 less EA at mesial side of implants (p=0.02).The regression of analysis implied the increase of DBL 1mm would cause 0.26mm 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>4mm (p=0.019; OR=2.1; 95% CI:1.13-3.92). 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.