Mirzaei M, Ghavam M, Rostamzadeh T
Assistant Professor, Department of Operative Dentistry, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
J Dent (Tehran). 2010 Spring;7(2):84-8. Epub 2010 Jun 30.
Preservation of unsupported occlusal enamel after removal of underlying carious dentin may result in maintenance of aesthetics as well as wear resistance against the opposing enamel. This study investigates the influence of different restorative materials and bonding agents on reinforcement of unsupported enamel in molars and compares it with sound dentin.
In this in vitro study, forty- five extracted human molars were selected and randomly divided into five groups of nine. All lingual cusps were cut off. The dentin underlying the buccal cusps was removed in all groups except the positive control. The negative control group received no restorations. After application of varnish and Panavia F, spherical amalgam (Sina) and after application of Single-Bond (3M), composite resin (Tetric Ceram) was used to replace missing dentin. All specimens were thermocycled, then mounted in acrylic resin using a surveyor. Lingual inclination of facial cusps was positioned horizontally. Load was applied by an Instron machine at a crosshead speed of 10 mm/min until fracture. Data were subjected to ANOVA (one way) and Post hoc Test (Duncan).
Statistically significant differences were found between the five groups (P<0.001); however, no significant difference was revealed between bonded amalgam and the positive control groups (P=0.762). Composite and amalgam had the same effect (P=0.642), while the composite and negative group had no significant difference (P=0.056).
Bonded amalgam systems (Panavia F) could reinforce the undermined occlusal enamel effectively.
去除龋坏的牙本质后保留无支持的咬合面釉质，可能有助于维持美观以及抵抗对颌釉质的磨损。本研究调查了不同修复材料和粘结剂对磨牙无支持釉质增强的影响，并将其与健康牙本质进行比较。
在这项体外研究中，选取45颗拔除的人类磨牙，随机分为五组，每组9颗。所有舌尖均被切断。除阳性对照组外，所有组的颊尖下方的牙本质均被去除。阴性对照组不进行修复。在涂覆清漆和Panavia F后，使用球形银汞合金（Sina），在涂覆Single-Bond（3M）后，使用复合树脂（Tetric Ceram）来替代缺失的牙本质。所有标本进行热循环处理，然后使用测绘仪固定在丙烯酸树脂中。颊尖的舌向倾斜度调整为水平。通过Instron机器以10 mm/min的十字头速度施加负荷直至断裂。数据进行单因素方差分析（ANOVA）和事后检验（Duncan检验）。
五组之间存在统计学显著差异（P<0.001）；然而，粘结银汞合金组与阳性对照组之间未发现显著差异（P=0.762）。复合树脂和银汞合金的效果相同（P=0.642），而复合树脂组与阴性对照组之间无显著差异（P=0.056）。
粘结银汞合金系统（Panavia F）可以有效地增强被削弱的咬合面釉质。
