OBJECTIVE: The aim of the present paper was to analyse, on patient and implant basis, factors related to peri-implant lesions.

MATERIAL AND METHODS: Two hundred and eighteen patients treated with titanium implants were examined for biological complications at existing implants 9-14 years after initial therapy. The effects of several potentially explanatory variables, both on patient and on implant levels, were analysed.

RESULTS: On the implant level, the presence of keratinized mucosa (p = 0.02) and plaque (p = 0.005) was associated with mucositis (probing depth > or =4 mm + bleeding on probing). The bone level at implants was associated with the presence of keratinized mucosa (p = 0.03) and the presence of pus (p < 0.001). On the patient level, smoking was associated with mucositis, bone level and peri-implantitis (p = 0.02, <0.001 and 0.002, respectively). Peri-implantitis was related to a previous history of periodontitis (p = 0.05).

CONCLUSIONS: Individuals with a history of periodontitis and individuals who smoke are more likely to develop peri-implant lesions.