Influence of storage on bond strength of deciduous teeth

Objectives: The aim of this study was to assess the influence of the storage media on deciduous teeth as to the strength of the interface dentine-adhesive following shear bond strength tests. Methods: Sixty-four human deciduous molar teeth were randomly divided into four groups of 16 teeth each. During 15 days, the teeth were stored as follows: (G1) liquid nitrogen over teeth immersed in saline; (G2) liquid nitrogen over dried teeth; (G3) teeth stored in a freezer at a temperature of -80°C; (G4 - control) teeth keep refrigerated at 4˚C. The teeth were then sectioned from mesial to distal displaying two halves, only one used for this study. The teeth were included into acrylic resin with the enamel facing outwards. The enamel was then removed with a grinding machine exposing the dentine surface. Samples with 3mm diameter and 2mm height were prepared with Single Bond® adhesive system and Z250® composite, cured with Optlight Plus® (Gnatus). The samples were submitted to shear strength test with the EMIC DL-2000 testing machine and digitally processed in the MT 100 test software. Results: One-way ANOVA test revealed no statistically significant differences amongst the means of shear strength of the groups (p=0.708). With regards to the type of failure, the chi-square test over the simulations (Monte Carlo) showed no dependence related to the groups (p=0.976). Conclusion: The type of storage media did not influence the shear resistance of the bonding agent at the interface adhesive-dentine.