Significance of keratinized mucosa/gingiva on peri-implant and adjacent periodontal conditions in erratic maintenance compliers

Background Given the fact that most patients are not regular compliers in supportive peri-implant maintenance programs, it is of interest to examine the significance of the peri-implant soft tissue characteristics in relationship to the onset of peri-implant diseases. Methods Based on an a priori statistical power calculation, a cross-sectional study was conducted on erratic peri-implant maintenance compliers (<2 times/year) to examine the significance of keratinized mucosa (KM) and gingival tissue (KT) on peri-implant and adjacent periodontal conditions in implants restored >= 3 years. Seven clinical parameters were recorded around implants and the adjacent buccal sites. Radiographic assessment was performed using periapical X-rays. In addition, a visual analog scale (VAS) was used to evaluate the impact of KM upon brushing comfort. The case definition used for peri-implant diseases was in accordance with the 2017 World Workshop on the classification of periodontal and peri-implant diseases and conditions. Results Overall, 37 patients with 45 edentulous gaps restored with 66 implants and 90 adjacent teeth were analyzed. On comparing a KM band of <2 mm versus >= 2 mm, with the exception of suppuration (P = 0.6), all the clinical and radiographic parameters were significantly increased when the KM band was <2 mm (P < 0.001). A significant correlation was observed between KM and KT (r = 0.55), though a lack of KM did not condition a lack of KT. In the presence of peri-implantitis, only bleeding on probing at the adjacent dentate sites was identified to be increased. Conclusions The presence of <2 mm of KM around dental implants in erratic maintenance compliers seems to be associated with peri-implant diseases. The lack of KM constitutes a site-specific phenomenon independent of the keratinized tissue present in the adjacent dentition (NCT03501537).