Inhibition of incipient caries lesion progression by different fluoridated varnishes

Abstract The aim of this in vitro study was to evaluate the potential of different fluoridated varnishes to inhibit the progression of incipient caries lesions after cariogenic challenge. Seventy-five enamel specimens of bovine teeth were prepared and selected based on the initial surface microhardness (SMH). The specimens were first subjected to artificial demineralization (in buffer solution) after which SMH was re-analyzed (SM1). They were then randomly assigned to five experimental groups: 1- CONTROL (pH cycling), 2 - MI VAR (MI Varnish with RECALDENTTM - CPP-ACP), 3 - PROFL (Profluorid®), 4 - CLIN (ClinproTM White Varnish with TCP), and 5 - DUR (Duraphat®) (n=15). The varnishes were applied in a thin layer and the specimens were then subjected to pH cycling for eight days. The SMH and cross-sectional microhardness (CSMH) were then analyzed (SM2). The fluoride and calcium ion concentrations in the solution were analyzed by the indirect method and atomic absorption spectrophotometry, respectively. Data were statistically analyzed by Student's t-test, ANOVA/Tukey-Kramer, or Kruskall-Wallis/Dunn tests for individual comparisons (p˂0.05). All varnishes led to significantly higher surface and subsurface remineralization compared with the control group but did not differ from each other. The varnishes with the highest fluoride release were: PROFL and CLIN, followed by MI VAR and DUR. The varnishes with significantly higher release of calcium were: DUR, CLIN, and PROFL. In conclusion, all commercial fluoridated varnishes tested have good potential to inhibit the progression of demineralization, regardless of the ion release mechanisms.

Resumo O objetivo deste estudo in vitro foi avaliar o potencial de diferentes vernizes fluoretados em inibir a progressão de lesões de cárie incipientes. Setenta e cinco espécimes de esmalte de dentes bovinos foram preparados e selecionados com base na microdureza superficial inicial (MDS/SM). Os espécimes foram submetidos à desmineralização artificial (em solução de Buskes), sendo então a MDS (SM1) reanalisada. Foram então distribuídos aleatoriamente em cinco grupos experimentais: 1- CONTROLE (pH cycling), 2 - MI VAR (MI Varnish with RECALDENTTM - CPP-ACP), 3 - PROFL (Profluorid®), 4 - CLIN (ClinproTM White Varnish with TCP), and 5 - DUR (Duraphat®). Os vernizes foram aplicados em camada fina e os espécimes foram então submetidos à ciclagem de pH por oito dias. A MDS final (SM2) e a microdureza transversal (CSMH) foram então analisadas. As concentrações de flúor e íons cálcio em solução foram analisadas pelo método indireto e espectrofotometria de absorção atômica, respectivamente. Os dados foram analisados estatisticamente pelo teste T de Student, ANOVA/Tukey-Kramer ou testes de Kruskall-Wallis/Dunn para comparações individuais (p˂0,05). Todos os vernizes levaram a uma remineralização superficial e subsuperficial significativamente maior em comparação com o grupo controle, não diferindo significativamente entre si. Os vernizes com maior liberação de flúor foram: PROFL e CLIN, seguidos de MI VAR e DUR. Os vernizes com liberação significativamente maior de cálcio foram: DUR, CLIN e PROFL. Pôde-se concluir que todos os vernizes fluoretados comerciais testados apresentam bom potencial de inibição da progressão da desmineralização, independentemente dos mecanismos de liberação de íons.

Effect of Xylitol Varnishes on the Inhibition of Demineralization in Vitro

Abstract Objective: To evaluate the efficacy of xylitol varnishes in the inhibition of enamel demineralization in vitro. Material and Methods: Bovine enamel blocks (n=120) were randomly allocated to four groups (n = 30), and the surface hardness (SH) was measured at baseline. The blocks were treated with the following varnishes: 20% xylitol, 20% xylitol plus F (5% NaF), Duraphat™ (5% NaF, positive control), and placebo (no-F/xylitol, negative control). The varnishes were applied and removed after 6 h of immersion in artificial saliva. The blocks were subjected to pH cycles (demineralization and remineralization for 2 and 22h/day, respectively, for 8 days). Surface and cross-sectional hardnesses were measured to calculate the percentage of SH loss (%SHL) and the integrated loss of the subsurface hardness (ΔKHN). Data were statistically analyzed using Kruskal-Wallis and Tukey's tests (p<0.05). Results: %SHL was significantly decreased by 20% xylitol plus F, Duraphat™, and 20% xylitol varnishes compared to placebo. The use of 20% xylitol plus F varnish led to a significantly lower percentage of SH loss compared to the use of 20% xylitol varnish without F. However, the experimental and commercial varnishes led to significantly lower subsurface demineralization compared to placebo and did not differ from each other. Conclusion: Xylitol varnishes, especially when combined with F, effectively prevent enamel demineralization (AU).