The effect of various storage methods and media on shear-bond strengths of dental composite resin to bovine dentine.

A variety of media and methods have been used to store teeth used in bond-strength studies of resin restorative materials to dentine. This study examined the effect of 2 months of storage using 11 different methods and media on the shear-bond strength of Z100 resin composite to bovine dentine mediated by Scotchbond Multi Purpose adhesive. Freshly harvested teeth were used as controls. The results showed that 7 of the l1 storage methods or media were similar in shear-bond strengths and bond-failure characteristics. Four of the 11 methods (irradiation, or storage in thymol, methanol, and glutaraldehyde) resulted in significantly lower shear-bond strengths and atypical shear-bond failure, indicating that these are the least desirable methods of tooth storage for studies of this type. This study has further shown that if insufficient numbers of fresh teeth are available for studies of shear-bond strength, then freezing is the preferred method of storage for the registration of high shear-bond strengths. It is also apparent that further investigations are needed to examine what post mortem changes occur in dentine, whether these changes are modified by various storage conditions, and whether they have any significant effect on bonding of resin composites.