engleski

Bond Strength of Glass-Hybrid and Glass-Ionomer Materials to Primary Dentine

Objectives Although new formulations of glass- ionomer (GI) restorative materials have been introduced, little is known on their performances in primary dentition. The aim of the study was to evaluate the microtensile bond strength (µTBS) of a glass-hybrid (GH), high- viscous (HV-) and resin-modified (RM-) GI restoratives to sound (SD) and caries-affected (CAD) primary dentine. Methods Occlusal cavities were prepared in 60 primary molars and randomly divided into two groups: SD and CAD. Teeth (n=6) were restored with a GH (Equia Forte HT, GC Int- EF), two HV-GI (Equia Fill, GC Int- E ; Ketac Molar, 3M ESPE- KM), and two RM-GI (Fuji II LC, GC Int- II, Photac Fill, 3M ESPE- PF) materials. Samples were immersed in artificial saliva at 37°C for 7 days, and subsequently exposed to the thermal aging (10.000×). Twelve microspecimens per group were formed and allowed to age in artificial saliva at 37°C for 7 days. µTBS was tested at loading rate of 0.5 mm/min until failure. Mode of failure was analyzed using an optical digital microscope (magnification 300×). Results The overall bond strength was higher for SD than for CAD (p<0.05, Mann-Whitney test). However, when µTBS to SD and CAD was compared for individual materials, difference was significant for E (5.07 MPa, 2.41 MPa), and PF (2.57 MPa, 0.93 MPa), while EF (4.05 MPa, 3.73 MPa), II (3.27 MPa, 1.93 MPa) and KM (1.40 MPa, 0.79 MPa) showed no differences. For both SD and CAD, EF and E showed higher µTBS compared to other GI restoratives (p<0.05, Kruskal-Wallis test). The most frequent mode of failure was adhesive, followed by mixed failure, with no differences between the subgroups (p>0.05, chi-square test). Conclusions Novel restorative formulations are likely to provide better bonding properties to both sound and caries-affected primary dentine compared to the previous generations of GI materials.

ion-releasing materials ; dentine ; bond strength

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