Onset, progression and resolution of experimental peri-implant mucositis at different abutment surfaces: A randomized controlled two-centre study.

OBJECTIVES: To assess the onset, progression and resolution of experimentally induced peri-implant mucositis lesions at abutments with different microstructures in humans.

MATERIAL & METHODS: In a randomized, controlled, interventional two-centre study, a total of 28 patients had received 28 target implants and were randomly allocated to either partially microgrooved (test) or machined (control) healing abutments. The study was accomplished in three phases, including a wound healing period (WH) following implant placement (12 weeks), a plaque exposure phase (EP-21 days) and a resolution phase (RP-16 weeks). Clinical (e.g. bleeding on probing-BOP), immunological (MMP-8) and microbiological (DNA counts for 11 species) parameters were evaluated.

RESULTS: The incidence of peri-implant mucositis at EPd21 was comparable in both test and control groups (60.0% versus 61.5%), but markedly lower at control abutments after a nonsurgical treatment and reconstitution of oral hygiene measures at RPw16 (46.7% versus 15.4%). At any follow-up visit (i.e. EP and RP), clinical parameters, MMP-8 levels and DNA counts of major bacterial species were not significantly different between both groups.

CONCLUSION: The onset, progression and resolution of experimental peri-implant mucositis lesions were comparable in both groups.