This study investigated the effect of silver diamine fluoride (SDF) and potassium iodide (KI) treatment on secondary caries prevention and tooth discolouration in glass ionomer cement (GIC) restoration. Cervical GIC restorations were done on 30 premolars with: Group 1, SDF + KI; Group 2, SDF (positive control); Group 3, no treatment (negative control). After cariogenic biofilm challenge, the demineralisation of dentine adjacent to the restoration was evaluated using micro-computed tomography (micro-CT) and Fourier transform infrared (FTIR) spectroscopy. The colour of dentine adjacent to the restoration was assessed using CIELAB system at different time points. Total colour change (∆E) was calculated and was visible if ∆E > 3.7. Micro-CT showed the outer lesion depths for Groups 1, 2 and 3 were 91 ± 7 µm, 80 ± 7 µm and 119 ± 8 µm, respectively (p < 0.001; Group 2 < Group 1 < Group 3). FTIR found that there was a significant difference in amide I-to-hydrogen phosphate ratio among the three groups (p < 0.001; Group 2 < Group 1 < Group 3). ∆E of Groups 1, 2 and 3 after biofilm challenge were 22.5 ± 4.9, 70.2 ± 8.3 and 2.9 ± 0.9, respectively (p < 0.001; Group 3 < Group 1 < Group 2). SDF + KI treatment reduced secondary caries formation on GIC restoration, but it was not as effective as SDF treatment alone. Moreover, a perceptible staining on the restoration margin was observed, but the intensity of discolouration was less than that with solely SDF treatment.

Background: Recent advances in enamel and dentine adhesive technology have resulted in the emergence of many new adhesive systems. Self‐etching bonding systems do not require a separate etching step and the newest systems are the “all‐in‐one” systems which combine etching, priming and bonding into a single application. This study reports laboratory enamel microshear bond strengths of a self‐etching priming and three all‐in‐one systems and also evaluates two different microshear bond test methods. Methods: One hundred and nineteen enamel specimens were bonded (0.8mm diameter) with either Clearfil Protect Bond (Kuraray), Xeno III (Dentsply), G Bond (GC) or One‐Up Bond F (Tokuyama) using Palfique Estelite resin composite and stored in 37°C water for seven days. The microshear bond test method used either a blade or wire to apply the shear stress. Results were analysed with one‐way ANOVA and post hoc (Tukey) multiple comparison analysis. Results: Clearfil Protect Bond demonstrated higher and more consistent bond strengths than Xeno III, G Bond or One‐Up Bond F. The wire method showed much greater reliability in results, with a coefficient of variation half that of the blade method. Conclusions: All‐in‐one adhesives seem to be less reliable than the two‐step self‐etching priming adhesive when bonding to enamel. Test method can significantly affect results in the microshear bond test method.

To study the effect of silver diamine fluoride (SDF) treatment and incorporating casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) into a glass-ionomer cement (GIC) to prevent secondary caries. A cervical cavity was prepared on 32 premolars for the following restoration groups: group 1, conventional GIC restoration; group 2, SDF (38%) treatment and conventional GIC restoration; group 3, CPP-ACP (3%) modified GIC; and group 4, SDF treatment and CPP-ACP modified GIC. The restored teeth were thermal-cycled before undergoing a multi-species cariogenic biofilm challenge. The restored teeth were examined by micro-computed tomography (micro-CT), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX) and Fourier transform infrared (FTIR) spectroscopy. Data were analyzed by two-way ANOVA. Micro-CT determined outer lesion depths for groups 1-4 were: 123±6μm, 87±7μm, 79±3μm and 68±5μm respectively. An interaction effect on the outer lesion depth was found between the restorative materials and SDF treatment (p<0.001). Both SDF treatment and modification with CPP-ACP had a significant effect on outer lesion depth (p<0.001). SEM/EDX showed an increase of calcium and phosphorus at the root dentine adjacent to the restoration in groups 3 and 4 (CPP-ACP modified GIC). FTIR revealed that SDF treatment and CPP-ACP modified GIC had a significant effect on amide I-to-hydrogen phosphate ratio on the material-root interface (p=0.001). SDF treatment and incorporation of CPP-ACP into GIC restorative material can prevent secondary root caries development. The results provide useful information to dentists in formulating clinical management protocols and material when treating root caries.