Effects of Different Coating Materials on the Flexural Strength and Bond Strength of Glass Hybrid Glass Ionomer to Dentin

Objective: To evaluate the effects of coated glass hybrid glass ionomer using nanofilled-resin and other materials on the flexural strength and microtensile bond strength of the glass hybrid glass ionomer to dentin.

Methods: This work was composed of three studies. 1) To evaluate the duration of the complete chemical reaction of the glass hybrid glass ionomer restorative material; 2) The study of microtensile bond strength between the glass hybrid glass ionomer restorative material and dentin; and 3) The evaluation of the flexural strength of glass hybrid glass ionomer by means of the three-point bending test.

In the first study, Fourier Transform Infrared Spectroscopy (FTIR) was used to evaluate the duration of the complete chemical reaction. The results of this study were used as the storage periods for the second and third studies.

In the second study, 96 sound human permanent molar teeth were sectioned parallel to the occlusal surface. Mid-coronal dentin surfaces were treated with GC DENTIN CONDITIONER.Then the glass hybrid glass ionomer – EQUIA® Forte was placed. The teeth were divided into four groups of 24 teeth each: Group 1 (negative control), without coating material; Group 2,3 and 4, where the glass ionomer restorations were coated with Fuji varnishTM, the adhesive element of OptibondTMFL, and EQUIA® Forte Coat, respectively. The teeth in each group were stored in distilled water at 37 oC under an experimental simulated pulpal pressure of 20 cmH2O, and then divided into three subgroups according to the storage time used in this study (24 hours, two weeks and four weeks), eight teeth per subgroup. Then the restored teeth were cut, using low-speed diamond saw, into stick specimens with a bond interface area of approximately 1 mm2. Four specimens were collected from each teeth (n=32). Microtensile bond strength was determined using a universal testing machine.The data were submitted to two-way ANOVA at a significance level of 95%. The mode of failure in the de-bonded specimens was determined using a Scanning Electron Microscope (SEM).

In the third study, 60 bar-shaped glass hybrid glass ionomer specimens of 25x2x2 mm3 were prepared in a split mold. The specimens were randomly divided into four groups according to the mentioned coating materials, 15 specimens per group. After applying the coating material, the specimens in each group were stored in distilled water at 37 oC and divided into three subgroups according to the storage time (24 hours, two weeks and four weeks), five specimens per subgroup. The three-point bending test was conducted using the universal testing machine. The data were submitted to two-way ANOVA and Tukey’s multiple comparison test (P<0.05).

Results: In the two- and four-week water-storage subgroups, there was no significant difference in microtensile bond strength regardless of the application of coating material. The coated glass ionomer specimens demonstrated significantly higher flexural strength values than did those in the control group. Remarkably, the specimens in the group in whichnanofilled-resin coating was applied showed the greatest flexural strength during all storage periods. Moreover, the periods of specimen storage significantly affected the microtensile bond strength and flexural strength of glass ionomer material.

Conclusions: Within the limitations of this study, the application of all mentioned coating materials, including the nanofilled-resin coating, exhibited no significant effect on the microtensile strength of the bond between the glass ionomer material and dentin. Nevertheless, the application of coating materials, especially nanofilled-resin coating, and the effect of storage duration, significantly improved the flexural strength of glass ionomer material, and had the tendency to improve the microtensile bond strength.

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Boonpong K, Ariyakriangkai W, Khuwuthayakorn Y, Kunawarote S. Effects of Different Coating Materials on the Flexural Strength and Bond Strength of Glass Hybrid Glass Ionomer to Dentin: Original articles. CM Dent J [Internet]. 2020 Jan 01 [cited 2024 Jul 23];42(1):61-81. Available from: https://www.dent.cmu.ac.th/cmdj/frontend/web/?r=site/viewarticle&id=16

Boonpong, K., Ariyakriangkai, W., Khuwuthayakorn, Y. & Kunawarote, S. (2020). Effects of Different Coating Materials on the Flexural Strength and Bond Strength of Glass Hybrid Glass Ionomer to Dentin. CM Dent J, 42(1), 61-81. Retrieved from: https://www.dent.cmu.ac.th/cmdj/frontend/web/?r=site/viewarticle&id=16

Boonpong, K., Ariyakriangkai Watcharaphong,Khuwuthayakorn Yutthana and Kunawarote Sitthikorn. 2020. "Effects of Different Coating Materials on the Flexural Strength and Bond Strength of Glass Hybrid Glass Ionomer to Dentin." CM Dent J, 42(1), 61-81. https://www.dent.cmu.ac.th/cmdj/frontend/web/?r=site/viewarticle&id=16

Boonpong, K. et al. 2020. 'Effects of Different Coating Materials on the Flexural Strength and Bond Strength of Glass Hybrid Glass Ionomer to Dentin', CM Dent J, 42(1), 61-81. Retrieved from https://www.dent.cmu.ac.th/cmdj/frontend/web/?r=site/viewarticle&id=16

Boonpong, K., Ariyakriangkai, W., Khuwuthayakorn, Y. and Kunawarote, S. "Effects of Different Coating Materials on the Flexural Strength and Bond Strength of Glass Hybrid Glass Ionomer to Dentin", CM Dent J, vol.42, no. 1, pp. 61-81, Jan. 2020.

Boonpong, K., Ariyakriangkai, W., Khuwuthayakorn, Y., et al. "Effects of Different Coating Materials on the Flexural Strength and Bond Strength of Glass Hybrid Glass Ionomer to Dentin." CM Dent J, vol.42, no. 1, Jan. 2020, pp. 61-81, https://www.dent.cmu.ac.th/cmdj/frontend/web/?r=site/viewarticle&id=16