The aim of this study was to compare different bacterial models for in vitro induction of non‐cavitated enamel caries‐like lesions by microhardness and polarized light microscopy analyses. One hundred blocks of bovine enamel were randomly divided into four groups (n = 25) according to the bacterial model for caries induction: (A) Streptococcus mutans, (B) S. mutans and Lactobacillus acidophilus, (C) S. mutans and L. casei, and (D) S. mutans, L. acidophilus, and L. casei. Within each group, the blocks were randomly divided into five subgroups according to the duration of the period of caries induction (4–20 days). The enamel blocks were immersed in cariogenic solution containing the microorganisms, which was changed every 48 h. Groups C and D presented lower surface hardness values (SMH) and higher area of hardness loss (ΔS) after the cariogenic challenge than groups A and B (P < 0.05). As regards lesion depth, under polarized light microscopy, group A presented significantly lower values, and groups C and D the highest values. Group B showed a higher value than group A (P < 0.05). Groups A and B exhibited subsurface caries lesions after all treatment durations, while groups C and D presented erosion‐type lesions with surface softening. The model using S. mutans, whether or not it was associated with L. acidophilus, was less aggressive and may be used for the induction of non‐cavitated enamel caries‐like lesions. The optimal period for inducing caries‐like lesions was 8 days. Microsc. Res. Tech. 78:444–451, 2015. © 2015 Wiley Periodicals, Inc.

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Introduction Methods of decontamination or sanitization of toothbrushes have been questioned. Objective This study assessed the effectiveness of pomegranate peels infusion as a disinfectant of toothbrushes against Streptococcus mutans. Material and method A sample of 16 schoolchildren aged between 7 and 9 years performed brushing 5 days/week, with a careful brushing once a day. After each day of brushing, the toothbrushes were washed and sprayed with one disinfectant solution. This procedure was repeated for 4 weeks using one of the different solutions per week: distilled water (G1; negative control), pomegranate (Punica granatum Linn) peels infusion (G2), 1% sodium hypochlorite (G3) and 0.12% chlorhexidine digluconate (G4). After the fifth day, toothbrushes were collected for laboratory analysis. Toothbrushes heads were subjected to agitation in saline dilution of 10–1, 10–2,10–3, and 25 μL of each dilution were seeded in mitis salivarius agar culture medium for S. mutans colony-forming unit (CFU) counting. One calibrated examiner (Kappa = 0.91) performed the CFU (mL–1 × 104) counts. Kruskal-Wallis and Dunn Multiple Comparison tests were used at a significance level of 5%. Result G1 presented the highest number of CFU (3.9 ± 8.4), followed by G2 (3.2 ± 4.0). No S. mutans growth was observed in G3 and G4. There was no statistically significant difference between G1 and G2 and between G3 and G4 (p>0.05). Conclusion Pomegranate infusion was completely ineffective for the disinfection of toothbrushes against S. mutans when compared with 1% sodium hypochlorite and 0.12% chlorhexidine digluconate solutions.

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 as the texture was assessed with visual validated criteria or ball-end probe.