Effect of silver diamine fluoride and potassium iodide on shear bond strength of glass ionomer cements to caries-affected dentine

Objective: To investigate the effect of silver diamine fluoride (SDF) and potassium iodide (KI) treatment on dentine discolouration and the shear bond strength (SBS) of glass ionomer cements (GICs) to artificial caries-affected dentine.

Materials and methods: Dentine slices from human molars were demineralised to mimic caries-affected dentine. They were randomly allocated for treatment (n = 20 per treatment) with SDF + KI, SDF (positive control) or water (negative control). All slices were immersed in the artificial saliva for 24 hours after treatments. The colour of the treated surfaces was assessed using the CIELAB system. Lightness values were measured. Total colour change (∆E) was calculated using water as the reference group, and was visible to the naked eyes if ∆E > 3.7. All dentine slices were bonded with GICs. The SBS was assessed using a universal testing machine. Colour parameters and the SBS were analysed using a one-way ANOVA test.

Results: The slices treated with SDF + KI had a higher lightness value those slices treated with water, whereas those treated with SDF presented a lower lightness value compared with those treated with water. The treatment with SDF + KI did not introduce any adverse colour effect to demineralised dentine (∆E = 14.4), whereas the application of SDF alone caused significant staining (∆E = 24.6). The SBS values (mean ± SD) after treatment with SDF + KI, SDF and water were 3.0 ± 1.4 MPa, 2.3 ± 0.9 MPa and 2.6 ± 1.1 MPa, respectively (P = 0.217).

Conclusion: The immediate application of KI solution after SDF treatment does not negatively affect adhesion of GICs to artificial caries-affected dentine. Moreover, KI treatment can reduce discolouration of demineralised dentine caused by SDF.