Evaluation of the clinical safety and performance of a narrow diameter (2.9 mm) bone-level implant: a 1-year prospective single-arm multicenter study

Purpose Narrow-diameter implants facilitate single- tooth restoration when interdental or inter-implant spaces and bone volume are inadequate for using standard diameter implants. This study reports the short-term data on the clinical safety and performance of a bone-level-tapered two-piece implant with a 2.9 mm diameter in the clinical practice setting. This study was retrospectively registered on March 1st, 2016 (NCT02699866). Methods Implants were placed in partially healed extraction sockets of the central and lateral incisors in the mandible and lateral incisors in the maxilla for single-tooth replacement. The primary outcome was to assess implant survival at 12 months after placement. Secondary outcomes included implant success, pink esthetic score, marginal bone-level changes, and safety. Results Twenty four males and 17 females with a mean age of 44.5 (+/- 18.3 standard deviation) received the implant. Three out of 41 implants were lost yielding a survival rate of 92.7% (95%- CI: 79.0%; 97.6%) at 1 year. One patient reported an ongoing foreign body sensation, pain, and/or dysesthesia at month 12. The average pink esthetic score at 6 months was 11.2 (95%-CI: 10.5; 11.9). The bone level was stable with a mean bone-level change of-0.3 mm (+/- 0.42 mm standard deviation) at 1 year after implantation. No serious adverse events or adverse device events were reported. Conclusions The use of a 2.9 mm diameter bone-level-tapered implant is a safe and reliable treatment option for narrow tooth gaps at the indicated locations. Overall performance and good survival rates support their use in cases, where wider implants are unsuitable.