Raghunath Reddy M H, Subba Reddy V V, Basappa N
Department of Pedodontics & Preventive Dentistry, Uttar Pradesh Dental College & Hospital, Faizabad Road, Lucknow, Utter Pradesh, India.
J Indian Soc Pedod Prev Dent. 2010 Oct-Dec;28(4):245-50. doi: 10.4103/0970-4388.76150.
An in vitro study was conducted to compare the retentive strengths of zinc phosphate, polycarboxylate and glass ionomer cements using Instron universal testing machine. Thirty preformed and pretrimmed stainless steel crowns were used for cementation on 30 extracted human primary molars which were divided into three groups of 10 teeth in each group. Then the teeth were stored in artificial saliva and incubated at 37°C for 24 h. A load was applied on to the crown and was gradually increased till the crown showed dislodgement, and then the readings were recorded using Instron recorder and analyzed for statistical significance. The surface area of crown was measured by graphical method. The retentive strength was expressed in terms of kg/cm 2 , which was calculated by the equation load divided by area. Retentive strengths of zinc phosphate (ranged from a minimum of 16.93 to amaximum of 28.13 kg/cm 2 with mean of 21.28 kg/cm 2 ) and glass ionomer cement (minimum of 13.69 - 28.15 kg/cm 2 with mean of 20.69 kg/cm 2 ) were greater than that of polycarboxylate cement (minimum of 13.26 - 22.69 kg/cm 2 with mean of 16.79 kg/cm 2 ). Negligible difference (0.59 kg/cm 2 ) of retentive strength was observed between zinc phosphate (21.28 kg/cm 2 ) and glass ionomer cements (20.69 kg/cm 2 ). Glass ionomer cements can be recommended for cementation of stainless steel crowns because of its advantages and the retentive strength was almost similar to that of zinc phosphate cement.
采用英斯特朗万能试验机进行了一项体外研究，以比较磷酸锌水门汀、聚羧酸锌水门汀和玻璃离子水门汀的固位强度。使用30个预制和预修整的不锈钢冠，在30颗拔除的人类乳牙上进行黏固，这些乳牙被分为三组，每组10颗牙。然后将牙齿保存在人工唾液中，并在37°C下孵育24小时。对牙冠施加负荷并逐渐增加，直到牙冠出现脱位，然后使用英斯特朗记录仪记录读数并进行统计学显著性分析。通过图形法测量牙冠的表面积。固位强度以kg/cm²表示，通过负荷除以面积的公式计算得出。磷酸锌水门汀的固位强度（范围为最小值16.93至最大值28.13 kg/cm²，平均值为21.28 kg/cm²）和玻璃离子水门汀（最小值13.69 - 28.15 kg/cm²，平均值为20.69 kg/cm²）大于聚羧酸锌水门汀（最小值13.26 - 22.69 kg/cm²，平均值为16.79 kg/cm²）。观察到磷酸锌水门汀（21.28 kg/cm²）和玻璃离子水门汀（20.69 kg/cm²）之间的固位强度差异可忽略不计（0.59 kg/cm²）。由于其优点，玻璃离子水门汀可推荐用于不锈钢冠的黏固，并且其固位强度与磷酸锌水门汀几乎相似。
