Dentin and Enamel Shear Bond Strengths of Nano-Composite Resin

Objective: The purpose of this study was to examine the bonding of NEUN (P) and an experimental bis-EMA composite resin (E) with fluorinated TEGDMA (F-T) to enamel and dentin using experimental bonding resins, containing F-T.

Method: TEGDMA, bis-EMA, HEMA, OptiBond SoloPlus (OB) and All-Bond 2 (AB) Light-curable, filled (f) and unfilled (u) bonding resins were made with F-T concentrations of 0, 17, 24, and 30 wt.%. Silanized barium silicate glass was used for the filled resins at 48 wt.%. Enamel and dentin, mounted in epoxy resin discs were 600 grit finished metallographically yielding a flat surface with a smear layer. Optibond Solo Plus and All-Bond 2 etchants and primers were used with the f and u experimental bonding resins to bond commercial (P) and experimental (E) composite resin cylinders 5 mm diameter and 2.5 heights to dental tissues. Five specimens for each group were made and stored at 37 ºC for 24 hr. These were tested in shear mode at 0.5 mm/min. in a universal testing machine 

Result: Bond strengths to enamel (EB) and dentin (DB) are presented in MPa.

	R1f0	R2f17	R3f30	R4f24	OB	R1u0	R2u17	R3u30	R4u24	AB
EBP	24±4	20±3	21±3	21±3	22±3	23±5	22±4	21±4	21±3	17±5
EBE	26±1	21±3	20±1	20±1	26±2	19±2	22±2	21±2	19±3	18±2
DBP	16±1	16±2	16±2	19±3	19±3	22±4	19±3	19±1	18±3	17±1
DBE	17±2	18±2	19±2	17±1	26±2	19±2	19±2	15±1	19±2	18±2

EB and DB data were analyzed separately using 3-way ANOVA with filler, F-T concentration, and composite resin type as dependent factors (p<0.05). Filler content was statistically significant; all other factors were not significant. With dentin bonding, many interactions were significant, only the type of composite resin and the presence of filler were not.

Conclusion: Enamel bonding is fairly consistent, irrespective of the bonding resin used but dentin bonding is more sensitive to resin formulation.