Purpose: The aim of this study was to evaluate the proximal contact alterations between implant-supported restorations and adjacent natural teeth with the passage of time. In addition, potential factors influencing proximal contact loss were also evaluated. Materials and Methods: Patients in need of implant-supported restorations in the posterior region were included. Proximal contact was divided into the following three groups: tight (group T), appropriate (group A), and open (group O). It was judged by dental floss (OralB, Essentialfloss) at restoration insertion and 1-year follow-up. In addition, patients' age, sex, implant sites, restoration type, retention type, and parafunction were recorded. Results: At 1-year follow-up, 74 patients with 144 proximal contacts were included. After 1-year follow-up, the proximal contact loss rate was 24.3%, and 45.1% of proximal contacts did not show any alterations. The proximal contact loss rates in group T at baseline were significantly lower than those in group A at baseline (12.9% and 32.9%, respectively; P = .03). The proximal contact loss rates in the mandible were significantly higher than those in the maxilla (37.2% and 9.1%, respectively; P .01). Other variables did not show a significant effect on proximal contact loss. Conclusion: Based on the current evidence, the proximal contact loss between implant-supported restorations and the adjacent teeth was frequent in the short term. It is helpful to reduce the proximal contact loss rate in the short term by making the proximal contact slightly tense at restoration insertion. Evaluation of proximal contact should be monitored carefully, especially in the mandible. Keywords: adjacent teeth, dental implants, proximal contact loss