Experimental Study About The Marginal Microleakage Of Four Filling Material For Posterior Teeth

Objective:To compare the marginal microleakage of the composite resin P60, TPH, Solitaire2 and silver amalgam in filling posterior teeth, so as to provide the experiment basic for the clinical treatment.Method:One hundred and twenty exvivo molar and premolar without dental caries and prepared with the same cavity shape (classⅡ) were assigned into four groups equally at random (group A. B. C. D). One group has 30. Group A were filled with P60 composite resin; Group B were filled with TPH composite resin; Group C were filled with Solitaire2 composite resin; Group D were filled with silver amalgam. After filling, all of the specimens were dipped into artificial salivary for 48 hours. After that, each of the four groups was again divided into two respectively (A1 and A2, B1 and B2, C1 and C2, D1 and D2). Group A1, B1, C1 and D1 were taken to have the test of temperature difference cycle under load and pressure test----put the specimens into 4°-40°C artificial salivary 100 times alternatively under load. Then put them under the piercer vertically and laterally. The value of the pressure was 60Kg. Group A2, B2, C2 and D2 were not taken the above test. Scanning electron microscope (SEM) was used to measure the crack between obturator and the hole and record them according to buccal wall, tongue wall and pulpal wall.Results:Statistic show that there were statistical significance between A1 and D1, B1 and D1, C1 and D1 (p<0.01 ). Between A2 and D2, B2 and D2, C2 and D2, it is the same(P<0.05). But there were no statistical significance between A1 and A2, B1 and B2, C1 and C2 (p>0.05), though there was statistical significance between D1 and D2(p<0.05).Conclusion:The obturator was still keep tight contact with the hole under the oral environment and masticatory pressure in filling composite resin P60, TPH and Solitaire2. But the crack increase under oral environment and masticatory pressure in filling silver amalgam. So it show that filling cavity with composite resin P60, TPH, Solitaire2 can reduce marginal microleakage and reinforce retention.