Microbiological and aMMP-8 findings depending on peri-implant disease in patients undergoing supportive implant therapy

•aMMP-8 level is not suitable to discriminate between healthy and peri-implant diseases.•Microbiological findings are similar between healthy, mucositis and peri-implantitis.•IL-1 polymorphism is no predictor for peri-implant diseases.•Smoking is potentially associated to peri-implantitis in SIT/SPT.

The aim of this study was to evaluate microbiological findings and aMMP-8 level of peri-implant mucositis (M) and peri-implantitis (P) in patients undergoing supportive implant therapy (SIT). Eighty-nine patients with 171 implants were included. The case definitions were as follows: M: PPD ≥4 mm, BOP; P: PPD ≥ 4 mm, BOP, radiographic bone loss ≥3.5 mm. Samples of peri-implant sulcular fluid (PISF) were taken from all peri-implant pockets at each implant to detect periodontal pathogens using PCR and aMMP-8 level with ELISA. Only Treponema denticola (Td) and Prevotella intermedia (Pi) showed significantly higher prevalence in P (healthy implants [HI]: Td = 27%, Pi = 17%; M: Td = 26%, Pi = 15%; P: Td and Pi = 50%; P < 0.05). The mean aMMP-8 level at implant sites did not show any significant difference (P = 0.05) among HI (5.2 ± 8.1), M (9.9 ± 19.0), and P (4.9 ± 7.7). Microbiological findings and aMMP-8 levels are not reliable criteria to distinguish between HI, M, and P in patients undergoing SIT.