Purk J H, Eick J D, DeSchepper E J, Chappell R P, Tira D E
Department of Operative dentistry, University of Missouri-Kansas City 64108.
Quintessence Int. 1990 Jul;21(7):545-51.
Two groups of maxillary premolars with Class I cavities were prepared with one marginal ridge thickness to a width of 1.0 mm. One group was restored with amalgam and the other group with composite resin. Two groups of Class II cavities also were prepared and restored with amalgam and composite resin. The teeth in the four treatment groups were subjected to a centric load at the marginal ridge until fracture occurred. A two-factor analysis of variance revealed a statistically significant difference between the class of preparation (Class I preparations were weaker than were Class II preparations) but differences in strength between restorative materials (composite resin versus amalgam) and the interaction effect (class of preparation x restorative materials) were not found to be statistically significant (alpha = .05). A Newman-Keuls sequential range test found no statistically significant differences in strength between groups (alpha = .05). Fracture patterns were observed under scanning electron microscope. Fractures extended into the enamel and into the material in the Class I composite resin, Class I amalgam, and Class II composite resin restorations. Fractures extended only into the material in Class II amalgam restorations.
制备两组具有I类洞型的上颌前磨牙，使一个边缘嵴厚度达到1.0mm宽。一组用银汞合金修复，另一组用复合树脂修复。还制备了两组II类洞型并用银汞合金和复合树脂修复。对四个治疗组的牙齿在边缘嵴处施加正中载荷直至发生折断。双因素方差分析显示，制备类别之间存在统计学显著差异（I类制备比II类制备更脆弱），但未发现修复材料（复合树脂与银汞合金）之间的强度差异以及交互作用效应（制备类别×修复材料）具有统计学显著性（α = 0.05）。Newman-Keuls序贯极差检验发现各组之间的强度无统计学显著差异（α = 0.05）。在扫描电子显微镜下观察折断模式。在I类复合树脂、I类银汞合金和II类复合树脂修复体中，折断延伸至釉质和材料内部。在II类银汞合金修复体中，折断仅延伸至材料内部。
