OBJECTIVES: This study evaluated microtensile bond strength of dentin adhesives to intact and decalcified caries-like root surfaces.
METHODS: Ninety-eight extracted human incisors were randomly divided into two groups as intact (Group INT) and decalcified (Group DEC). The roots of DEC teeth were coated with nail varnish, leaving a 6 mm wide window on the buccal surfaces before being placed in a demineralization solution to produce artificial carious lesions in root dentin. Root surfaces below the cemento-enamel junction were slightly ground with sandpaper discs and treated with either Scotchbond Multi Purpose (SMP), Adper Easy Bond (AEB), Scotchbond SE (SSE), Clearfil SE Bond (CSE), Clearfil TriS Bond (CTS), FL-Bond II (FLB), FL-Bond Shake One (FSO). Each group comprised 7 intact and 7 decalcified roots. Composite build-ups (3 mm high, 6 mm long) were formed on the bonded surfaces. All Specimens were thermocycled (2000 cycles, 5° to 55°C) and sectioned horizontally into 1 mm thick slabs. Hour-glass shaped specimens with an area of 1 mm2 at the bonded interface were prepared and subjected to microtensile testing. Resin-dentin interfaces were observed with SEM. Wilcoxon signed-rank test was used for statistical analysis (p≤0.05).
RESULTS:
Groups | DEC (n=15) Mean±SD [MPa] | INT (n=18) Mean±SD [MPa] |
CSE | 23.1±11.6a | 32.0±9.6d |
FLB | 19.5±9.4ab | 25.4±4.3ad |
SMP | 20.5±13.1ab | 27.0±7.3ad |
FSO | 16.4±8.5b | 17.8±4.5b |
AEB | 21.7±10.0ab | 21.2±7.1b |
CTS | 17.4±8.5b | 16.4±9.2 b |
SSE | 20.3±9.0ab | 12.3±9.1c |
Groups with different superscript letters were significantly different.
Bond strengths with FLB, SMP, FSO, AEB, and CTS were the same on intact and decalcified root surfaces while CSE and SSE revealed significant differences in bond strength to the two surfaces. Bond strengths of CSE were dramatically decreased on decalcified root surfaces.
CONCLUSION: Bond strength values were similar to intact and decalcified root surfaces with most dentin adhesives tested.