Jokstad A, Mjör I A
Department of Anatomy, School of Dentistry, University of Oslo, Norway.
Acta Odontol Scand. 1990 Dec;48(6):389-97. doi: 10.3109/00016359009029070.
The effect of variations in the design of class-II cavity preparations on the marginal degradation of amalgam restorations was included as a study aim in a clinical trial. Four hundred and sixty-eight restorations were placed in 210 patients by 7 Scandinavian dentists using 5 different alloys. The marginal degradation was scored on impressions of the restored teeth by means of a six-point ordinal rating scale. The scores were then compared with defined characteristics of the occlusal parts of the initial cavity preparations. Characteristics of the cavity that could be related to the marginal degradation were diverging occlusal cavity walls, occlusal cavity depth, fissures perpendicular to the cavosurface angle, and rough or variable occlusal cavosurface angles. Cavity preparation features not influencing the rate of degradation were the occlusal width, the location of the cavosurface angle on the cusp slope, occlusal cavosurface angles with sectors smaller than 90 degrees, and less than 1 mm enamel remaining between the cavity preparation and another restoration. The association between the different cavity design features and the marginal degradation varied with the different alloys. Superior marginal performance is probably the result of optimal condensation or surface treatment, rather than features of the cavity preparation.
在一项临床试验中，二类洞型预备设计的变化对汞合金修复体边缘劣化的影响被纳入研究目标。7位斯堪的纳维亚牙医使用5种不同合金，为210名患者放置了468个修复体。通过六点有序评分量表对修复牙齿的印模上的边缘劣化进行评分。然后将分数与初始洞型预备咬合部分的特定特征进行比较。与边缘劣化相关的洞型特征包括咬合面洞壁发散、咬合面洞深、垂直于洞缘角的裂隙以及粗糙或变化的咬合面洞缘角。不影响劣化速率的洞型预备特征包括咬合面宽度、洞缘角在牙尖斜面上的位置、扇形小于90度的咬合面洞缘角以及洞型预备与另一个修复体之间剩余的釉质小于1毫米。不同洞型设计特征与边缘劣化之间的关联因不同合金而异。边缘性能优越可能是最佳凝聚或表面处理的结果，而非洞型预备的特征。
