• Nakajima, M.
• Miura, H.
• Tagami, J.
• Foxton, Richard Mark

Abstract

This study evaluated the regional tensile bond strength of a dual-cure resin composite core material to root canal dentin using photo and dual-cure adhesives and different modes of polymerization. Nineteen extracted premolars were decoronated and their root canals prepared to a depth of 8 mm and a width of 1.4 mm using Para Post drills. For the microtensile bond strength (muTBS) test, 15 roots were randomly divided into five groups and their canal walls treated with a dual-cure self-etching primer (Clearfil Liner Bond 2V Primer, Kuraray Medical Co, Japan). Adhesive resin (Clearfil Liner Bond 2V Bond A) was applied to two of the groups and light cured for 20 seconds. A dual-cure adhesive resin (Clearfil Liner Bond 2V Bond A+B, Kuraray Medical Co, Japan) was applied to the remaining three groups, one of which was light cured. The post spaces of all the groups were filled with a dual-cure resin composite (DC Core) and three were light cured for 60 seconds from a coronal direction. Chemical-cure resin composite was placed on the outer surfaces of the roots, which were then stored in water for 24 hours. They were serially sliced perpendicular to the bonded interface into eight 0.6 mm-thick slabs, then transversely sectioned into beams approximately 8 x 0.6 x 0.6 mm for the muTBS test. All of the failure modes were observed under SEM and analyzed using the Kruskal-Wallis Rank test. For Knoop hardness testing, four specimens were prepared in a similar manner, two were light-cured and the other two chemically-cured. The specimens were longitudinally sectioned into two pieces, and three indentations were made at 100 mum intervals from a coronal to an apical direction in the eight halves. Data were divided into two groups (coronal/apical halves of post space) and analyzed using two-way ANOVA and Scheffe's test (p0.05). Light exposure of both the adhesive resin and resin composite resulted in significantly higher muTBS than chemical-cure alone (p

Topics

• surface
• scanning electron microscopy
• strength
• composite
• hardness
• etching
• resin
• hardness testing