IADR Abstract Archives
Effect of lightcuring through ceramics on shear-bond-strength of adhesive luting-materials
Objectives:
Evaluation of the effect of reduced curing-light intensity upon irradiation through CAD-on ceramics on dentin shear-bond-strength (SBS) of five different adhesive luting cements compared to direct lightcuring and selfcuring.
Methods:
Seventy-five bovine incisors embedded in resin were wet-ground with P400 SiC-paper to expose dentin surfaces. For each group (n=5), primers/adhesives were applied following manufacturer's instructions without optional steps and lightcured if required. Freshly lightcured composite cylinders (Tetric EvoCeram, Ivoclar Vivadent; Ø=2.35mm) were placed onto teeth using the corresponding cements. After excess-removal, cements were either lightcured, lightcured through CAD-on-ceramic (1mm IPS e.max CAD HT A3 on 1mm IPS e.max ZirCAD MO2 using 0.1mm IPS e.max CAD Crystall./Connect 5 resulting in shade A3) or selfcured (15min, 23°C). Curing light intensity was 650mW/cm² (Bluephase, Ivoclar Vivadent), curing times were chosen according manufacturer's instructions. After 24h storage (water, 37°C) SBS were measured (Z010, Zwick-Roell).
Materials tested were Multilink Automix, Multilink Primer (MLAM), Ivoclar Vivadent; RelyX Ultimate, Scotchbond Universal (RXSU), 3M ESPE; Nexus NX3, OptiBond All-In-One (N3OB), Kerr; Panavia F2.0, ED-Primer II (PFED), Kuraray; Duo-Link, All-Bond Universal (DLAB), Bisco.
Data was analyzed using two-way-ANOVA (Tukey's, p<0.05).
Results:
SBS [MPa]:
curing mode of luting material | MLAM | RXSU | N3OB* | PFED | DLAB* |
lightcure (dualcure) | 27.9±6.6a;A | 33.0±5.9a;A | 25.9±3.6a;A | 13.6±1.9b;A | 27.0±3.8a;A |
lightcure (dualcure) through ceramic | 24.0±6.2a;A | 20.4±4.4a,b;B | 25.5±8.4a;A | 5.5±3.8c;B | 12.4±6.1b,c;B |
selfcure | 28.3±4.8a;A | 3.1±5.9c;C ** | 14.5±2.6b;B | 10.1±3.8b,c;A,B | 17.3±3.9b;B |
Small letters in rows and capital letters in columns indicate equal statistical groups.
*Adhesive was lightcured **Three debondings before measurement
Conclusions:
Lightcuring gave the highest SBS, except for MLAM, where selfcure exceeded lightcure values (though non-significantly). Lightcuring through ceramic significantly decreased SBS compared to direct lightcuring for all materials except MLAM (selfcuring primer) and N3OB (lightcured adhesive). Lightcuring through ceramic of MLAM, PFED and DLAB led to non-significantly lower SBS compared to selfcure. The only material in this test, showing consistently high SBS values regardless of curing-mode was MLAM, also giving the significantly highest SBS upon selfcure.
The dentist should be aware, that lightcuring through ceramic supraconstructions significantly reduces SBS for most materials. For reliable good adhesion in all clinical situations, materials with high SBS upon selfcure are the best choice.