The purpose of this study was to evaluate the sealing ability of smear layer removal and 4 dentin primers of dentin bonding agents to obturate the root canal. 126 extracted human teeth with single, straight canal and mature apices were used. Samples were classified into six groups(presence of smear layer, absence of smear layer. Scotchbond Bond Multi-Purpose, All Bond 2, Mac Bond 2 and Clearfil Liner Bond 2) and positive control. All teeth except positive control were obturated with thermoplasticized gutta-percha and AH26.
Electrochemical and dye penetration technique were used to evaluate the degree of microleakage through rcxx canal. Seventy teeth were immersed in a. 1 percent potassium chloride solution and applied external power supply(DC 10 V) to the circuit for electrochemical microleakage test. Microleakage was determined over period of 28 days and evaluated.
Forty eight teeth were used in dye infiltration technique. All specimen were suspended in 2 percent methylene blue dye for 1 week and then longitudinally split. The value of dye infiltration was measured under a stereomicxoscope at x 10 magnification and evaluated.
The results were as follows :
1. All groups showed that apical microleakage increased throughout the test period and a group having smear layer was especially increased in electrochemical test(p<0.05). In a group having smear layer, the degree of apical microleakage was the highest, and the microleakage was much higher than in smear layer removed group in electrochemical test(p<0.05). Scotchbond Multi-Purpose, All Bond 2, Mac Bond 2 and Clearfil Liner Bond 2 showed lower microleakage than a groups having smear layer, especially All Bond 2 and Clearfil Liner Bond 2 treated groups were the lowest microleakage in electrochemical test(p<0.05).
2. There was no significant difference among experimental groups in dye penetration technique.
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