Mucosal inflammation and incidence of crestal bone loss among implant patients: a 10-year study

Objective: The objective of this prospective study was to determine the prevalence and incidence of marginal bone loss and, in addition, peri-implantitis in subjects and implant sites after 10 years in function. Material and Methods: One hundred and thirty-three subjects with a total of 407 implants that had been in function for about 5 years attended a follow-up visit in 2007 (visit 2; V2). 100 of the 133 subjects returned for a new clinical and radiographic examination in 2012 (visit 3; V3). The clinical examination included assessment of "bleeding on probing" (BoP+) and "probing pocket depth." Subjects with implant sites that in the radiograph exhibited crater-shaped marginal bone loss of >0.5 mm were identified as losers. Results: During the interval between V2 and V3 (about 5 years), 13 implants in 7 subjects exhibited progressive bone loss and were removed. The overall amount of crestal bone loss that had occurred at the remaining implants between visit 1 (V1; >= 1 year of loading) and V3 (10 years) was small (0.36 +/- 1.4 mm). The bone-level reduction was twice as great between V2 and V3 as between V1 and V2. Forty subjects and 75 (26%) implant sites exhibited marginal bone loss of >0.5 mm between V1 and V3. In the interval between V2 and V3, 37 new implant sites lost significant amounts of bone. During the entire 10-year period (V1-V3), 12% of patients and 5% of implants displayed signs of peri-implantitis (bone loss >0.5 mm, BoP+, PPD >= 6 mm), while in the V2-V3 interval, the corresponding numbers were 10% (patients) and 4% (implant sites). Conclusion: Sites with marginal bone loss of >= 1 mm were not common among implant patients. Peri-implantitis occurred in about 10% of patients and 4% of implant sites.