2012 Volume 55 Issue 2 Pages 165-174
The purpose of this study was to investigate the effectiveness of resin bonding to root canal dentin of a new chemical-cure resin bonding system, compared to the dual-cure resin bonding system. Extracted human premolars were used in this study. Crowns of the teeth were sectioned at the cement-enamel junction using a low-speed diamond saw. Pulpal tissue was removed by using endodontic files, and post spaces were prepared by using post drills in a low-speed handpiece to a depth of 5 or 10 mm and diameter of 1.4 mm. The roots were randomly divided into two groups, and their root canal dentin surfaces treated with one of the following self-etching primers: 1) dualcure system Estelite-Core Quick Bond (DC) or 2) chemical-cure system DBC-510 Trial product (CC). Post holes were filled with a dual-cure composite resin core material, excess resin was removed and resin in the root canal was light-cured. Each root was then cut parallel to the long axis. The resin-dentin interfaces were then observed with a scanning electron microscope (SEM) and surface profile measurement microscope. The other side, specimens of 5 mm depth were classified into upper (rd1) and lower part (rd2), and specimens of 10 mm depth were classified into upper (RD1), upper of middle (RD2), lower of middle (RD3) and lower part (RD4). Then, the bond strength of each part of the specimens was measured by the microtensile bond strength test. The results of surface analysis by SEM and surface profile measurement microscope revealed no gaps at the interface in both specimens of DC and CC. DC provided a higher bond strength than CC, and RD1 of DC provided a higher bond strength than RD4 of DC. CC provided a lower bond strength than DC. However, there was no significant difference in the bond strength between the lower and upper parts. It is suggested that the DBC-510 chemical-cure system (CC) achieves good resin bonding to root canal dentin regardless of the depth of post hole.
