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Updated: Jun 5, 2025
Quasistatic Mechanical Testing for Computer-Aided Design and Manufacturing Occlusal Veneers Cemented to Milled Dentin Analog Material
Published on: December 20, 2024
An In-vitro Evaluation of the Shear Bond Strength to Dentin and Microhardness of Different Restorative Materials
Background:
The mentioned advantages of bulk-fill composite resin and high-viscosity glass ionomer restorative materials have increased their use in restorative dentistry in recent years; accordingly, the bonding of these materials to dental tissues and their mechanical properties have become more important.
Aim:
This study aimed to evaluate the effects of different application methods on Vicker's hardness and shear bond strength of three different restorative materials.
Methods:
In this in-vitro study; Teflon molds were used for the microhardness test. In the control group, reinforced high-viscosity glass ionomer, high-viscosity glass ionomer, and flowable bulk-fill composite resin were applied by the manufacturer's instructions. In other groups, preheating, ultrasonic activation, and both preheating and ultrasonic activation were applied, respectively (n = 14). Microhardness values of the upper surfaces of the specimens were measured with Vicker's hardness measuring device. For the shear bond strength test, 84 intact human molar teeth were used. The teeth were sectioned two in the mesiodistal direction (n = 14). The materials were applied to the dentin using the same placement protocols as those used in the hardness test. After the specimens were maintained at 37°C for 24 h, the shear bond strength test was performed using a universal test device.
Statistical Analysis Used:
The data were analyzed using SPSS 26.0 at a 95% confidence level. The Mann-Whitney test was also used for the statistical analysis of the data (P = 0.05).
Results:
Preheating the restorative materials significantly decreased the shear bond strength in the flowable bulk-fill composite resin group (11.77 ± 4.46 MPa) compared with that in the control group (12.14 ± 4.23 MPa) (P < 0.05) but significantly increased the shear bond strength in the reinforced high-viscosity glass ionomer group (3.91 ± 2.93 MPa) (P < 0.05).
Conclusions:
It can be concluded that preheating before application may increase the shear bond strength of reinforced high-viscosity glass ionomer.
