IADR Abstract Archives
Difference In Dentin Demineralization Using Different Phosphoric Acid Application Protocols
Objectives: This study evaluated the effect of different etching times of four commercial phosphoric acids on demineralization pattern, roughness of dentin and chemical mapping, as well as resin-dentin microtensile bond strength (μTBS) and nanoleakage (NL).
Methods: The following commercial phosphoric acid were used: Ultra-etch [ULE], Scotchbond Universal Etchant [SUE]; Dentsply Dental Conditioner [DDC] and Total Etch [TTE]. After occlusal dentin exposure of 188 molars, the phosphoric acid was applied for 3 and 15s.The demineralization dentin patterns were observed in SEM (occlusal and lateral view). The roughness of the conditioned surfaces was measured by optical profilometry and Micro-Raman spectra were used for chemical mapping. After completing restoration, specimens were sectioned into resin-dentin sticks and tested for µTBS and NL. All data were statistical evaluated by two-way ANOVA and Tukey’s test (Tukey α = 0.05).
Results: After 15s of etching, a smaller depth of demineralization was verified for ULE compared to DDC and TTE, while SUE showed an intermediate behavior (p = 0.001). No differences were observed after 3s of etching (p> 0.05).The ULE and SUE obtained similar results with a lower tubular density compared to DDC and TTE (p = 0.001). Both roughness and chemical mapping showed a lower demineralization rate at 3s for all groups (p < 0.002) except ULE acid, which showed similar behavior at 3 and 15 s (p > 0,05). The μTBS and NL values were significantly better in ULE and SUE than DDC and TTE for both 3 and 15 s of etching (p <0.05). The ULE acid showed greater demineralization control, followed by SUE acid, which had a positive impact on the bonding process.
Conclusions: Three seconds dentin etching time cause significant changes in the dentin structure, but it is enough to guarantee an adequate monomer penetration into the demineralized dentin, without jeopardizing the bond strength and reducing nanoleakage.
Methods: The following commercial phosphoric acid were used: Ultra-etch [ULE], Scotchbond Universal Etchant [SUE]; Dentsply Dental Conditioner [DDC] and Total Etch [TTE]. After occlusal dentin exposure of 188 molars, the phosphoric acid was applied for 3 and 15s.The demineralization dentin patterns were observed in SEM (occlusal and lateral view). The roughness of the conditioned surfaces was measured by optical profilometry and Micro-Raman spectra were used for chemical mapping. After completing restoration, specimens were sectioned into resin-dentin sticks and tested for µTBS and NL. All data were statistical evaluated by two-way ANOVA and Tukey’s test (Tukey α = 0.05).
Results: After 15s of etching, a smaller depth of demineralization was verified for ULE compared to DDC and TTE, while SUE showed an intermediate behavior (p = 0.001). No differences were observed after 3s of etching (p> 0.05).The ULE and SUE obtained similar results with a lower tubular density compared to DDC and TTE (p = 0.001). Both roughness and chemical mapping showed a lower demineralization rate at 3s for all groups (p < 0.002) except ULE acid, which showed similar behavior at 3 and 15 s (p > 0,05). The μTBS and NL values were significantly better in ULE and SUE than DDC and TTE for both 3 and 15 s of etching (p <0.05). The ULE acid showed greater demineralization control, followed by SUE acid, which had a positive impact on the bonding process.
Conclusions: Three seconds dentin etching time cause significant changes in the dentin structure, but it is enough to guarantee an adequate monomer penetration into the demineralized dentin, without jeopardizing the bond strength and reducing nanoleakage.