Shear–Bond-Strength of Self-Adhesive Resin Cements (Lithium Disilicate/Zirconia) to Dentin

Objectives: To compare the shear bond strength (SBS) of an experimental novel fluoride releasing self-adhesive resin cement SI-R21003 (Group 1, Shofu), to Maxcem Elite (Group 2, Kerr) and RelyX Unicem2 Clicker (Group 3, 3MESPE) luting systems when luting lithium disilicate (LiDi) or zirconia (Zir) ceramic to dentin.

Methods: Forty two dentin samples (n=7) were polished down to 320-grit with silicon carbide paper on a polishing wheel running at 110 RPM(Ecomet, Buehler).  The ceramic buttons, LiDi (e.maxCAD, IvoclarVivadent) or Zir (Lava, 3MESPE), were made approximately 3mm in diameter and 2.5mm in height. The buttons were polished down to 600-grit with SiC paper on a polishing wheel at 110 RPM and surface treated according to manufacturer's instructions.  Each luting system was applied according to the manufacturer's instructions and the ceramic was applied with constant 5N load. Specimens were cleaned of excess cement and light-cured for 10seconds with an LED light (SmartLite MAX, Dentsply). All specimens were stored in distilled water for 24hours at 37°C and then were subjected to thermocycling for 2000 cycles between 5-10°C and 55-60°C. The SBS of the specimens were tested using a Universal Testing Machine (Instron5566A, Norwood,MA) with a 500N load cell and cross-head speed of 1mm/min. The data was analyzed using one-way ANOVA with post-hoc analysis conducted through Fisher LSD. A P-value <.05 was considered statistically significant.

Results:

Group #	Ceramic	SBS After Thermocycling (MPa±SD)
1	LiDi	6.27±2.84
	Zir	8.11±3.67
2	LiDi	2.31±0.86
	Zir	3.67±0.81
3	LiDi	8.19±2.53
	Zir	8.21±4.52

Conclusions: Group 1 and 3 yielded higher shear bond strength compared with Group 2 for both LiDi and Zir .There were no significant differences between group 1 compared with group 3  (p>.05)