Investigation of Shear Bond Strength for Self Etch Adhesive Resins

Objectives: To study the quantitative effect on shear bond strength of composite resin to dentin using a dual cure self-etch adhesive with and without following the manufacturer prescribed protocol. 

Methods: Three commercial composites and one dentin bonding system were studied.  Dentin bond strengths were measured using a dentin bonding system with and without the use of a chemical reagent. 

Results:  No significant differences were found between composites under different bonding conditions (p<0.05).  In general, the dual cure composite materials showed a loss in bond strength when compared using the dual cure adhesive to the light cure adhesive.  The Hyperfil (Parkell, Edgewood, NY) had a 75% loss in bond strength.  The greatest mean bond strength for the Hyperfil (Parkell, Edgewood, NY) material was (23.1±10) MPa bond when using the dual cure adhesive material and (16.2±9) MPa for the light cure adhesive.  The light cure composite EPIC (Parkell, Edgewood, NY) showed a higher bond strength with the single cure, chemical or light cure adhesives 18.8 (18.8±7) MPa and  (18.7±10) MPa respectively.  The bond using the dual cure adhesive was (17.4±8) MPa. 

Conclusions: The dual cured composite resins showed greater variability in bond strengths by varying the adhesive protocol.   These composites performed best when using the dual cure adhesive protocol.  The light cure composite displayed greater bond strengths when using either a single cure light or chemical protocol.  These results would suggest that bond strengths may be effected by the compatibility of material and variations to the manufactures instructions.