Comparison of endodontic sealers in terms of shear strength.

Objectives: To measure shear strengths of joint at dentin/sealant interface
Methods: Total 14 samples of elephant tusk dentin were cut and prepared for shear bond strength test. Then samples were divided into two groups with 7 samples each. Samples were 2.4 mm in thickness with 1.6 mm of canal size. Total 14 small pieces of wire were cut to insert into the prepared canal with cement to evaluate its shear bond strength. One end of wire was smoothened on struers kruth rotor 3 machine. For Group 1 mineral trioxide aggregate was mixed and carefully applied on the wire as well as some portion in the small prepared canal on 7 samples. Similarly for Group 2 glass ionomer cement was mixed and carefully applied on the wire as well as some portion in the small prepared canal on 7 samples. Samples were left overnight for the cement to set and gain its maximum strength. Then samples with wire inside were placed on metal support and checked for shear bond strength with the help of shear testing machine (instron). Jog of instron testing machine was moved down slowly until it touches the wire. Speed was adjusted at 0.5000 mm/minute. Readings were noted and graphs were plotted in excel.
Results: The results for shear bond strength in both Groups 1 & 2 are as follows,
GROUP 1 = MTA = 0.30714 MPa (mean value)
GROUP 2 = GIC = 1.74 MPa (mean value)
So it was noted that shear bond strength of MTA was less than GIC. It was noted that there was poor adhesion of MTA with wire and dentin as well, thats why results showed very less value for MTA.
Conclusions: Shear bond strength of GIC (1.74 MPa) is better than MTA (0.30714 MPa) and is better material to be used as endodontic sealer.