Long-term evaluation of hard and soft tissues around transmucosal implants with a convergent neck: a 10-year cohort study

Purpose: The aim of the present study was to analyse the 10-year hard and soft tissue variations around two-piece transmucosal implants characterized by a hyperbolic neck. Methods: This cohort study was initiated in 2014 and included patients receiving single-tooth implants as part of routine clinical care. A flapless approach was followed to place implants in healed crests (ITI bone 2 or 4). A post-extractive placement was performed in presence of unrestorable teeth without acute infections (ITI bone 1). Implant loading procedures were similar in all cases, following a provisional crown after 3 months and a definitive metal ceramic restoration at 4 months. Patients were enrolled in a structured recall program with clinical and radiographic evaluations. Marginal Bone level (MBL) and Pink Esthetic Score (PES) were used as indexes of hard and soft tissue stability. The onset of new systemic diseases and pharmacological therapies were recorded at 6- and 10-year follow-up. MBL and PES were modeled as continuous outcomes using linear regression with cluster-robust standard errors at the patient level. Separate models were fitted including each predictor (age group, CVDs, antihypertensive therapy), follow-up time (six vs. ten years), and their interaction. Results: After 10 years, 37 implants in 30 patients were available for clinical or radiographic evaluation. Implant survival and success rates were 100% at the 10-year follow-up, with marginal bone loss remaining below 2 mm. At 10 years, mean MBL was 0.90 (95% CI 0.68 to 1.12 mm) while mean PES was 11.1 (95% CI, 10.6 to 11.6). No statistically significant associations were observed between cardiovascular conditions or antihypertensive therapy and changes in MBL (p > 0.050); in contrast, PES soft tissue scores demonstrated a modest but significant reduction between six and ten years (mean change - 0.8; p < 0.001), with consistently lower values in older patients and in patients with cardiovascular disease. Conclusions: Within the limitations of this study, transmucosal implants with a convergent neck showed stable marginal bone levels over a 10-year follow-up. The occurrence of new systemic conditions related to aging did not appear to significantly affect MBL in this cohort. However, their potential impact should be further investigated in future long-term studies.