The effect of CPP-ACP and Nd:YAG laser on the bond strength of softened dentin

Abstract

The purpose of this study was to investigate the effect of CPP-ACP treatment and Nd:YAG laser on microtensile bond strength (µTBS) of softened dentin. Sixty samples were obtained from thirty sound third molars. All samples were submitted to dentin softening procedure, by the immersion of the specimens in 30 mL of Sprite Zero for 30min. Afterwards, the samples were randomly divided according to the CPP-ACP treatment: CG-Control group; MP-treated with CPP-ACP paste (MI Paste); MPP-treated with CPP-ACP+900 ppm NaF paste (MI Paste Plus). Each group was further divided according to bonding procedure: NL-No laser; L-Laser irradiation after adhesive application and before polymerization. The laser parameters used were 1.4 W, 10 Hz, 140 mJ/pulse, with an optic fiber of 320 µm, generating energy of 174 J/cm 2 per pulse. All samples were restored with Clearfil SE Bond/Filtek Z350 XT. After 24 h, the restored samples were cut into beams (± 1 mm 2 adhesive interface area) and subjected to a µTBS test. Data were analyzed by two-way ANOVA test and Holm-Sidak post-hoc method (α = 0.05). The treatment with CPP-ACP pastes did not significantly affect softened dentin µTBS (p = 0.070). Statistic revealed significant reduction on µTBS values for CG/L, leading to the rejection of the second null hypothesis (p < 0.001). Both CPP-ACP based pastes did not affect µTBS of softened dentin for the adhesive system utilized. The Nd:YAG laser irradiation after application of adhesive system did affect µTBS values of softened dentin samples untreated with CPP-ACP based pastes.

Impact of Various Resin Adhesive Strategies on Micro Shear Bond Strength to Sound, Caries- Affected and Remineralized Dentin Substrates: An in-Vitro Esem Analysis

“…Superficial dentin demineralization means limited decalcification which in turn did not result in complete dissolution of HA crystals but kept them in place which led to more stable calcium salts and in turn increased the bond efficacy. (43,44) On the other hand, this result was in disagreement with Kamozaki et al, 2015 (32) who concluded that, the bond strength of softened dentin was not influenced by the application of any CPP-ACP based paste types, while another one revealed increase in bond strength after remineralization of softened dentin although this increase was not statistically significant. (33) In previous investigations where CPP-ACP was applied for 60 minutes per day and the treatment was repeated for seven days, the results reported higher bond strength values compared to the non treated group.…”

“…Single application of approximately 0.5mm layer of the paste was spread over the exposed CAD surface using a clean gloved finger for each specimen and left for five minutes undisturbed. (32) Then, the remineralizing agent was rinsed with deionized water until all remnants were removed and re-stored in daily renewed deionized water. This procedure was repeated once daily for seven days.…”

“…(28,29) In the literature, the effect of remineralizing efficiency of CPP-ACPF is still not clear as it revealed no significant effect on the bond strength to normal and CAD. (32) While another study reported a high significant effect for normal dentin than CAD and the remineralized dentin. (33) On the other hand, MI paste treated dentin samples had statistically higher bond strength than non-treated one.…”

Efeito dos tratamentos dessensibilizantes na evolução de lesões erosivas na dentina

“…A partir desse momento a erosão ocorreu progressivamente, representada pela curva ascendente e descendente da rugosidade e do perfil. Esta característica pode ser explicada pelo fato de que o processo erosivo é caracterizado pelo "amolecimento" inicial da superfície e consequente perda da estrutura amolecida (KAMOZAKI et al, 2015) que ocorreu sucessivamente durante a ciclagem de 9 dias.…”

“…Assim, dentre as possíveis intervenções, o tratamento restaurador pode ser eleito a fim de proteger a dentina exposta e produtos dessensibilizantes podem ser indicados para prevenção e tratamento da sensibilidade (KAMOZAKI et al, 2015 (MEIER et al, 2010) foi observado que o produto obliterou os túbulos dentinários de forma efetiva sendo este resistente a desafios erosivos e de força mecânica (escovação mecânica). Contudo, poucos trabalhos investigaram a eficácia do nanomaterial na superfície do esmalte e dentina sendo os resultados controversos entre si (COMAR et al, 2013;MEDEIROS et al, 2014).…”