The overhang rate in posterior teeth restorations among a sample of patients from Sari City, Iran, in year 2017

ACKGROUND: Overhang is the extension of restoration material from the prepared cavity. Restoration overhangs have an important role in plaque accumulation, caries, severe gingival inflammation, and periodontal diseases. Therefore, the aim of this study was to determine the frequency of restoration overhanging, and the managements in order to reduce its prevalence and subsequent complications. METHODS: This descriptive cross-sectional study was conducted on 277 patients, who had at least one restoration in the proximal surface of posterior teeth. At first, all the patients were examined using a mirror, and dental floss under the light of the dental chair. In cases in which the existence of the overhang was suspected, Bitewing radiography was operated on respective regions. Data were analyzed using SPSS software. RESULTS: 120 teeth had overhangs (19.60%) and 492 (80.39%) exhibited no overhangs. From 120 restorations with overhang, 76 (63.33%) were amalgam restorations, and 44 (36.66%) were composite restorations. In total, 55.83% of them (67 restorations) were in maxilla and 44.16% (53 restorations) were in mandible. The prevalence of overhang in mandible was as 37.73% in mesial regions, 54.71% in distal regions, and 7.54% in mesial-occlusal-distal (MOD) regions; in addition, the prevalence rate in maxilla was as 38.80% in mesial regions, 58.20% in distal regions, and 2.98% in MOD. CONCLUSION: The overall frequency of restoration overhang was 19.60%, most of which was in amalgam restorations in comparison to composite restorations; and it is mostly seen in distal surfaces of maxillary teeth.