先天性欠如上顎側切歯に対するワンピース型細径インプラントの5年多施設共同研究

This prospective multicenter study evaluated the 5-year clinical performance of one-piece, long, smooth-necked narrow-diameter implants (NDIs) in rehabilitating patients with congenital maxillary lateral incisor agenesis and limited alveolar bone.

Patients aged ≥ 18 years with unilateral or bilateral agenesis and mesiodistal spaces of 3.5-5.5 mm were recruited. Flapless implant placement of Ø2.7 mm, smooth-necked implants was performed, followed by immediate loading with lithium disilicate crowns. Radiographic assessments of marginal bone levels, peri-implant soft tissue parameters, and esthetic outcomes were conducted at baseline, 1 month, 1 year, and 5 years. Implant survival, success, and mechanical/biological complications were systematically recorded. Statistical analyses employed Kaplan-Meier survival curves and ANOVA with significance set at p < 0.05.

Forty-six patients completed the 5-year follow-up. Implant survival and success rates were 97.8% and 93.5%, respectively. Mean marginal bone loss was 0.43 ± 0.06 mm at 1 year and 0.84 ± 0.11 mm at 5 years. Probing depths and bleeding indices remained within normal limits (2.96 ± 0.1 mm at 5 years). Papilla preservation was achieved in 89% of cases, and pink esthetic scores indicated stable soft tissue integration. Mechanical complications were minimal, with two cementation failures and one minor ceramic chipping; no implant or abutment fractures occurred.

One-piece NDIs represent a reliable, esthetic, and cost-effective treatment option for maxillary lateral incisor agenesis in patients with limited alveolar dimensions. High survival, minimal bone loss, stable soft tissue, and low complication rates support their use as a minimally invasive, patient-centered solution.