Influence of Concentration and Activation on Hydrogen Peroxide Diffusion through Dental Tissues In Vitro

This study evaluated the effect of physical and chemical activation on the diffusion time of different concentrations of hydrogen peroxide (HP) bleaching agents through enamel and dentin. One hundred and twenty bovine cylindrical specimens were divided into six groups (n = 20): 20% HP; 20% HP with light activation; 20% HP with manganese gluconate; 35% HP; 35% HP with light activation; and 35% HP with manganese gluconate. The specimens were fixed over transparent epoxy wells with internal cavities to simulate a pulpal chamber. This chamber was filled with an enzymatic reagent to simulate pulpal fluid. The bleaching gels were applied on enamel surface and the image of the pulpal fluid was captured by a video camera to monitor the time of peroxide penetration in each specimen. ANOVA analysis showed that concentration and type of activation of bleaching gel significantly influenced the diffusion time of HP (P < 0.05). 35% HP showed the lowest diffusion times compared to the groups with 20% HP gel. The light activation of HP decreased significantly the diffusion time compared to chemical activation. The highest diffusion time was obtained with 20% HP chemically activated. The diffusion time of HP was dependent on activation and concentration of HP. The higher concentration of HP diffused through dental tissues more quickly.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Bleaching Gels Containing Calcium and Fluoride: Effect on Enamel Erosion Susceptibility

This in vitro study evaluated the effect of 35% hydrogen peroxide (HP) bleaching gel modified or not by the addition of calcium and fluoride on enamel susceptibility to erosion. Bovine enamel samples (3 mm in diameter) were divided into four groups (n=15) according to the bleaching agent: control—without bleaching (C); 35% hydrogen peroxide (HP); 35% HP with the addition of 2% calcium gluconate (HP + Ca); 35% HP with the addition of 0.6% sodium fluoride (HP + F). The bleaching gels were applied on the enamel surface for 40 min, and the specimens were subjected to erosive challenge with Sprite Zero and remineralization with artificial saliva for 5 days. Enamel wear was assessed using profilometry. The data were analyzed by ANOVA/ Tukey’s test (P<0.05). There were significant differences among the groups (P=0.009). The most enamel wear was seen for C (3.37±0.80 μm), followed by HP (2.89 ± 0.98 μm) and HP + F (2.72 ± 0.64 μm). HP + Ca (2.31 ± 0.92 μm) was the only group able to significantly reduce enamel erosion compared to C. The application of HP bleaching agent did not increase the enamel susceptibility to erosion. However, the addition of calcium gluconate to the HP gel resulted in reduced susceptibility of the enamel to erosion

Bleaching Gels Containing Calcium and Fluoride: Effect on Enamel Erosion Susceptibility

This in vitro study evaluated the effect of 35% hydrogen peroxide (HP) bleaching gel modified or not by the addition of calcium and fluoride on enamel susceptibility to erosion. Bovine enamel samples (3 mm in diameter) were divided into four groups (n = 15) according to the bleaching agent: control-without bleaching (C); 35% hydrogen peroxide (HP); 35% HP with the addition of 2% calcium gluconate (HP + Ca); 35% HP with the addition of 0.6% sodium fluoride (HP + F). The bleaching gels were applied on the enamel surface for 40 min, and the specimens were subjected to erosive challenge with Sprite Zero and remineralization with artificial saliva for 5 days. Enamel wear was assessed using profilometry. The data were analyzed by ANOVA/ Tukey&apos;s test (P &lt; 0.05). There were significant differences among the groups (P = 0.009). The most enamel wear was seen for C (3.37 ± 0.80 µm), followed by HP (2.89 ± 0.98 µm) and HP + F (2.72 ± 0.64 µm). HP + Ca (2.31 ± 0.92 µm) was the only group able to significantly reduce enamel erosion compared to C. The application of HP bleaching agent did not increase the enamel susceptibility to erosion. However, the addition of calcium gluconate to the HP gel resulted in reduced susceptibility of the enamel to erosion

Prevalence of White Spot Caries Lesions in Primary Teeth in Preschool Children: Systematic Review and Meta-analysis.

BACKGROUND The first clinically detectable stage of caries lesion is a non-cavitated white spot lesion (WSL). The detection of early stages of caries lesions allows non-invasive management by fluoride usage, oral hygiene and diet control. There is a lack of information in the literature regarding the prevalence of these caries lesions in preschool children, which is important especially for public health strategies. OBJECTIVE The aim of this study was to conduct a systematic review with meta-analysis to verify the WSLs prevalence in primary teeth of preschool children. METHODS A literature search with MEDLINE/PubMed, Scopus, Web of Science, and Open Gray databases was conducted. Included studies fulfilled the eligibility criteria. Meta-analyses were performed using random effects model, for prevalence of pooled WSLs and subgroups analyses. RESULTS The search strategy identified 4922 potentially relevant articles, with final inclusion of 16 studies. The pooled prevalence of WSLs in primary teeth was 14.0% (95% CI: 8.0-24.0), without publication bias (p=0.2668). For subgroup analyses, an increase in WSLs prevalence for children of low-income economy (24.0%; 95% CI: 20.0-28.0), for age >31 months (22.0%; 95% CI: 12.0-37.0), for validated visual criteria assessment (20.0%; 95% CI: 11.0-33.0), and for tactile assessment with ball-ended probe (26.0%; 95% CI: 11-50.0) were detected. CONCLUSION It is suggested that the prevalence of WSLs in primary teeth of preschool children increases in countries with low income economy, with age greater than 31 months or texture assessment with visual validated criteria or ball-ended probe. PROSPERO Registration: Protocol number #CDR42017078434

Caneppele, “Influence of concentration and activation on hydrogen peroxide diffusion through dental tissues in vitro

This study evaluated the effect of physical and chemical activation on the diffusion time of different concentrations of hydrogen peroxide (HP) bleaching agents through enamel and dentin. One hundred and twenty bovine cylindrical specimens were divided into six groups ( = 20): 20% HP ; 20% HP with light activation; 20% HP with manganese gluconate; 35% HP; 35% HP with light activation; and 35% HP with manganese gluconate. The specimens were fixed over transparent epoxy wells with internal cavities to simulate a pulpal chamber. This chamber was filled with an enzymatic reagent to simulate pulpal fluid. The bleaching gels were applied on enamel surface and the image of the pulpal fluid was captured by a video camera to monitor the time of peroxide penetration in each specimen. ANOVA analysis showed that concentration and type of activation of bleaching gel significantly influenced the diffusion time of HP ( &lt; 0.05). 35% HP showed the lowest diffusion times compared to the groups with 20% HP gel. The light activation of HP decreased significantly the diffusion time compared to chemical activation. The highest diffusion time was obtained with 20% HP chemically activated. The diffusion time of HP was dependent on activation and concentration of HP. The higher concentration of HP diffused through dental tissues more quickly