Microshear bond strength and microleakage of glass ionomer cement on aged dentin

Abstract

Objective: To compare the microshear bond strength and microleakage of glass ionomer cements when bonded to aged and young dentin.

Background: Root caries commonly occurs in elderly patients. Glass ionomer cement (GIC) is frequently used to restore root caries. Many studies of GIC have been conducted using young dentin, however few studies have assessed adhesion and microleakage of GICs to aged dentin.

Materials and methods: Seventy-eight non-carious human molars (patient age 16-30 = 39; patient age ≥ 65 = 39) were tested with three commercial GICs (Fuji II LC, Equia Forte Fil, and Fuji BULK). For microshear bond strength (µSBS), teeth were horizontally sectioned and embedded in resin and three tubes attached to the sectioned surface. Materials were mixed and injected into the tubes, allowed to set and the tubes removed leaving the GIC cylinders. Specimens were stored in deionized water for 24 h at 25°C and subjected to a shear force in a universal testing machine. For microleakage, a buccocervical cavity was prepared, restored with GIC, and stored in deionized water for 24 h at 25°C. The specimens were polished, coated with nail varnish, placed in 0.5% basic fuchsin for 24 h, sectioned at the midpoint and evaluated for microleakage under a stereomicroscope and scanning electron microscope (SEM).

Results: For µSBS, Fuji II LC showed the highest bond strength among all three products (young dentin, 7.29 MPa; aged dentin, 8.59 MPa; P < 0.001). There was no significant difference between age groups. For microleakage, Fuji II LC had more dye penetration (P < 0.01) and there was significant difference between age groups. (Occlusal: P = 0.007, Gingival: P = 0.02)

Conclusion: After bonding of GICs, aged dentin showed no difference in µSBS but less microleakage when compared to young dentin.