Objective

To assess compressive strength of glass ionomer and composite resin restorations in premolar class I cavities.

Material and methods

In vitro experimental study to assess compressive strength of two types of stomatological restoration materials, using as object of study 52 bi-radicular premolars. Samples were distributed into four groups with different characteristics such as restorative material and cavity depth (2-4 mm). Glass ionomer and composite resins were the used restorative materials. Grouped samples were subjected to a compressive vertical force using a EZ-S SHIMADZU texturometer, until achieving the material's fracture. Obtained data were subjected to the Shapiro-Wilk test in order to assess data normalcy, null hypothesis was rejected. Total data analysis was conducted with t-Student test for independent samples.

Results

Data obtained after assessing superficial hardness of different restorative materials showed the existence of statistical differences which favored composite resin when compared to glass ionomer at both depths (p = 6.908 × 10-11 and p = 0.000). In intra-group comparison, a significant different was found between both groups (resin and glass ionomer) at different depths (p = 0.000155887 and p = 0.00257443).

Conclusion

Assessment of 4 mm tooth cavities restored with Tetric N-Ceram resin revealed greater hardness than those accomplished with Vitremer® resin at 2 and 4 mm and with the same resin at 2 mm depth.