Factors associated with the presence of peri-implant buccal soft tissue dehiscences: A case-control study

Background To identify factors associated with the presence of buccal soft tissue dehiscences (BSTD). Methods This cross-sectional observational study assessed 52 cases (CAS) with a minimum of 24 months of loading, with the presence of a BSTD, defined as an exposure of the prosthetic abutment, the implant neck or the implant surface in the anterior maxillae or mandible (premolar-premolar) and 52 carefully selected controls (CON) matched for age and years in function, being the only difference between groups the BSTD. Clinical parameters and radiographic findings from periapical radiographs and Cone Beam Computed Tomographies (CBCT) were analyzed to assess their association with the occurrence of BSTD using a multivariate regression model. Results The CAS had a mean keratinzed mucosa (KM) of 1.65 +/- 1.31 mm, whereas in the CON KM was 3.27 +/- 1.28 mm (P = 0.001). Probing depths were similar in both groups, whereas bleeding on probing and plaque scores were higher in the CAS (P = 0.001). Mean bone level scores in the CAS were 1.71 +/- 1.04 mm, and 1.27 +/- 1.01 mm in CON (P = 0.143). The first bone to implant contact at the buccal aspect was 4.85 +/- 3.12 mm in CAS and 2.15 +/- 3.44 mm in CON (P = 0.001). CAS were 1.48 +/- 0.93 mm outside the alveolar envelope, whereas the CON were 0.46 +/- 0.77 mm. Implants buccally positioned in the CBCT's were 34 times more likely to belong to the case group. The presence of >2 mm of KM at the time of evaluation, presence of adjacent natural teeth, cemented restorations and two-piece implants were protective factors. Conclusion The bucco-palatal implant position was the most relevant factor related to the presence of BSTD.