临床研究表明,牙折是11%～13%银汞合金修复物重新更换的主要原因,并占后牙修复物的5%。由于后牙牙折常常终止于游离龈嵴之下,因而常会造成修复上的困难。第一磨牙,特别是下颌第一磨牙牙折的发生率较高,这可能是因为它们易患龋病因而常作修复的缘故。修复过的牙齿较未修复过的牙齿更易发生折裂.(牙合)面预备窝洞的范围越宽,发生牙折的频率越高。修复两个牙面以上比只修复两个牙面,前者更易发生牙折.上牙弓与下牙弓、男性与女性之间,牙折的发生率无明显差异。较高的牙折发生率见于40岁以下的患者,这些牙折大多终止在釉牙骨质界以上。本研究的目的在于评价引起后牙牙折的一些因素,特别是患者年龄、牙髋活力、牙折的位置及终止点。作者研究观察了1986年～1987年间在雅典大学牙学院牙体病科接受治疗的患者,检查他们的后牙折断 Clinical studies have shown that dental folds are the main reason for the replacement of amalgam restorations by 11% to 13% and account for 5% of posterior teeth prostheses. As the posterior teeth fold often terminates below the free gum crest, which often causes difficulties in repair. The first molar, especially the first mandibular first molar, had a higher incidence of fractures, probably because they are predisposed to caries and are therefore often repaired. The repaired tooth is more prone to fracture than the non-repaired tooth. (Occlusal) Face The wider the range of prefabricated cavities, the higher the frequency of tooth creases. There was no significant difference in the incidence of dental folds between the upper and lower dental arch, male and female, than the other two. The higher incidence of tooth fractures seen in patients under the age of 40, most of these teeth stop in the glazed cementum above. The purpose of this study was to evaluate some of the factors that cause tooth fractures in the posterior teeth, in particular, the age of the patient, the activity of the hip and hip, the position of the tooth crease, and the termination point. The authors looked at patients treated at the Department of Teethology, College of Dentistry, University of Athens, 1986 - 1987 and examined their fractures of the posterior teeth