Long-term clinical and radiographic outcomes of a bone-level, 2-piece, internal connection implant system with coronal microthreads over 10 years of follow-up: a retrospective clinical study.

Purpose: This study retrospectively investigated the long-term clinical and radiographic outcomes of a bone-level type, 2-piece, internal connection dental implant system characterized by coronal microthreads.

Methods: A total of 872 implants placed in 284 patients were selected from 1,845 implants placed in 691 patients by experienced periodontists at Yonsei University Dental Hospital. These selected implants had been followed up for over 10 years and were included in the present study. A statistical evaluation of implant survival and treatment success, based on changes in marginal bone levels, was conducted using electronic records and consecutively taken radiographs.

Results: Over a follow-up period of 12.3±2.0 years, 830 of the 872 implants remained intact, yielding a cumulative survival rate of 95.2% at the implant level and 88.4% at the patient level. The cumulative treatment success rates, characterized by marginal bone loss of less than 2 mm, stood at 87.0% for implants and 76.1% for patients. Among the 830 surviving implants, 113 fixtures were classified as ailing, with an average marginal bone loss of 4.09±1.44 mm. Cox regression analysis revealed that implants 8 mm in length or shorter were significantly more likely to fail or experience pathologic marginal bone resorption, with hazard ratios of 3.71 and 2.00, respectively (P<0.05).

Conclusions: The survival and treatment success of the investigated microthreaded, bone-level, 2-piece, internal connection implants were acceptable over a follow-up period exceeding 10 years. However, shorter dental implants exhibited a higher propensity for failure and excessive marginal bone loss.