Comparison of Microleakage and Shear Bond Strength (SBS) of Dyad Flow and Tetric Flow in Primary Molars: An In-vitro Study

Abstract

Introduction: Early diagnosis combined with conservative adhesive treatment of occlusal caries may preserve the integrity of the remaining tooth and increase its longevity. Aim: To compare microleakage and Shear Bond Strength (SBS) of Dyad flow and Tetric flow in primary molars. Materials and Methods: Microleakage test: Eighteen samples were utilised separately for SBS and Microleakage. Standard Class I tooth cavity were prepared on occlusal surface of all teeth. The samples of Group 1 group were restored with Dyad flow restorative material; Samples of Group 2 were restored with Tetric flow and subjected to thermocycling in customized thermocycling device. Further, the samples were soaked in freshly prepared 2% Rhodamine B dye solution for 24 hours. The samples were then sectioned in bucco-lingual direction with hard tissue microtome under constant water flow and were observed under confocal microscope at 4× magnification and evaluated for die penetration. Eight out of nine samples were graded III, where as the other sample was graded as II based on ISO microleakage scoring system. Shear Bond Strength Test: A 2 mm high cylindrical polyethylene tube with an internal diameter of approximately 2 mm was placed on the dentin surface of each specimen. No etching or bonding was done for samples of Group 1 (Dyad flow), Optibond bonding agent was applied to the prepared buccal surface of the specimens in group 2 (Tetric Flow) and cured for 20 seconds. Flowable resin composite was injected into the tube and polymerized for 40 seconds using an LED curing unit. All specimens were subjected to thermocycling from 5°C and 55°C for 500 cycles. SBS testing was done following thermocycling. Specimens were secured in the holder of a universal testing machine and sheared with a knife-edge blade at a crosshead speed of 1.0 mm/minute. Independent t-test was performed for statistical significance. Results: Microleakage Test: There was no significant difference in microleakage between Dyad Flow and Tetric flow (p<0.05). Inter-examiner reliability was done between the accessors and the probability was 0.65 and 0.73. Shear bond strength test: No statistical significance was observed between the groups (p=0.51). The highest mean SBS value was recorded for group 2 in Tetric flow (29.83±21.4 MPa), whereas the lowest value was recorded for group 1 in Dyad flow (24.15±3.5 MPa). Conclusion: Dyad flow and Tetric flow had similar microleakage. Whereas, Mean SBS of Dyad flow was lower than Tetric flow. With the results of this study, Dyad flow can be used for class I cavities of primary molars.

Keywords

• conventional flowable composite
• primary molars
• self adhesive flowable composite
• shear bond strength
• microleakage