Purpose: Narrow dental implants are commonly used to restore narrow alveolar ridges. Although the good performance of narrow dental implants supporting multiple prostheses has been repeatedly demonstrated, there are few studies analyzing their performance in a long-term follow-up together with the influence of the loading protocol. Thus, the objective was to assess the influence of implant loading protocol (immediate vs delayed) on the long-term outcomes of 3.0-mm-diameter dental implants supporting fixed multiple prostheses.

Materials and methods: This retrospective cohort study included 202 3.0-mm-diameter dental implants supporting multiple prostheses placed between January 2006 and April 2009. Immediate loading was performed when the implants were inserted in bone types I, II, and III and achieved an insertion torque ≥ 25 Ncm; otherwise, delayed loading was performed. The survival of the dental implants was recorded together with clinical and demographic information of the participants. The prosthetic complications (ceramic chipping, screw loosening, screw fracture, decementation, prosthesis failure) were also recorded. The marginal bone loss since insertion and the marginal bone loss since loading were calculated.

Results: Delayed implant loading was performed in 131 implants and immediate loading in 71 implants. The follow-up time was 106 ± 40 months and 117 ± 38 months in the delayed and immediately loaded implants, respectively. The implant loading protocol (delayed vs immediate) showed no influence on the implant survival rate (96.2% vs 97.2%) and the marginal bone loss since insertion (1.2 ± 1.0 mm vs 1.2 ± 1.0 mm).

Conclusion: The implant loading protocol (immediate vs delayed) did not influence the long-term outcomes (survival and marginal bone loss) of 3.0-mm-diameter dental implants supporting fixed multiple prostheses. These results are in favor of considering immediately loaded narrow dental implants as a viable treatment alternative for horizontally resorbed ridges. Nevertheless, future randomized clinical trials are needed to confirm these observations.