Assessment of Narrow-Diameter Implants Placed in the Posterior Region for Rehabilitation with a Single Crown: A Retrospective Cross-Sectional Clinical Study.

OBJECTIVE: Alveolar ridge atrophy is the result of extensive bone resorption. In cases where the available bone does not allow placement of standard-diameter implants without grafting, short and extra-short implants or narrow-diameter implants (NDI) may be used. NDIs exhibit high survival rates, reaching 95.5% after a nine-year follow-up. Thus, the goal of the present study was to evaluate outcomes of NDIs rehabilitated with a single crown in the posterior regions of the maxilla and the mandible. MATERIALS AND METHODS: Patients treated with Ti-Zr NDIs in the posterior region with single crowns were screened. Radiographic and clinical examinations were performed to evaluate marginal bone loss (MBL), peri-implant probing depth (PPD), bleeding on probing (BoP), mobility, palpation, and percussion. Digital images were analyzed to measure and evaluate proximal bone loss. The implants were divided into groups: Group I (Success), II (Satisfactory), III (Compromised), and IV (Failure). The Kruskal-Wallis test was used (p=0.05). RESULTS: A total of 25 patients (56 Ti-Zr NDIs) were evaluated (mean follow-up: 3.3±1.1 years), with 100% survival rate; no mobility or pain was observed. The mean PPD was 2.11±0.65 mm, and BoP was present in 79.2% of cases. Radiographic analysis showed a mean mesial MBL of 0.83 ± 0.64 mm and a distal MBL of 0.91±0.78 mm. No significant correlation was found between MBL and PPD (p=0.45) or BoP (p=0.26). According to the success criteria, 91% (n=49) of implants were classified as successful (Group I), 7% (n=4) as satisfactory (Group II), and 2% (n=1) as compromised (Group III), with no failures recorded. CONCLUSION: NDIs in the posterior regions rehabilitated with a single-unit crown are a reasonable, reliable, and feasible option for oral rehabilitation.