Organic volume and permeability variations in the surface layer of artificial and natural enamel carious lesions

OBJECTIVES

Test the hypothesis the type of enamel caries (natural, artificial induced by gel, and artificial induced by acid solutions) affect the organic volume and the permeability of the surface layer in enamel caries lesions.

DESIGN

Artificial enamel caries, induced by either acidic solution (organic-poor; Group 1) or acidic gel (organic-rich; Group 2), and natural non-cavitated inactive approximal enamel caries lesions (NEC; Group 3) were obtained, from which longitudinal ground sections were prepared. Measurements of the mineral (V_min) (by microradiography), and water (α) and organic (β) volumes (by optical birefringence) were obtained at three points in the surface layer (n = 30/group).

RESULTS

The main outcomes were the ratio between experimental β by predicted β (β Ratio) and the ratio between experimental and predicted permeabilities (α_d Ratio). β Ratio in Group 1 was lower than in Groups 2 (Cohen's d: -1.81; 95% CI:-1.45,-2.32; p < 0.001) and 3 (Cohen's d: -0.71; 95% CI:-0.27,-1.18; p = 0.004), and Group 2 surpassed Group 3 (Cohen's d: 0.49; 95% CI:0.07,0.94; p = 0.03). α_d Ratio in Group 1 was higher than in Groups 2 (Cohen's d: 1.86; 95% CI:1.49,2.33; p < 0.001) and 3 (Cohen's d: 0.60; 95% CI:0.18,1.14; p = 0.01), and Group 3 surpassed Group 2 (Cohen's d: 0.61; 95% CI:0.23,1.07; p = 0.01).

CONCLUSIONS

The highest organic volume and the lowest permeability occurred at the surface layer of gel-induced artificial enamel caries lesions, which should be preferred in in vitro studies on de- and remineralization and resin infiltration.

Hormones and Auditory Perception: Study of Dichotic Listening in Women during the Menstrual Cycle

Introduction  Dichotic listening refers to the ability to hear different sounds presented to each ear simultaneously. Objective  The aim of the present study was to assess dichotic listening in women throughout the menstrual cycle. Methods  The volunteers who met the eligibility criteria participated in a dichotic listening assessment composed of three tests: 1) staggered spondaic word test; 2) dichotic digits test; and 3) consonant-vowel test. The female participants were tested during two different phases of the menstrual cycle: the follicular (days 11 to 13) and luteal (days 23 to 26) phases. The phases were confirmed by measuring serum levels of the hormone estradiol. Results  A total of 20 volunteers aged 18 to 49 years participated in the study (9 females and 11 males). In test 1, only the right ear of females showed better performance during the follicular phase (high estrogen levels), compared with the luteal phase (low estrogen levels); in test 2, there were no significant differences for any of the groups; and in test 3, both males and females showed significantly better performance in their right ear compared with their left ear. Conclusion  The better performance of females during the follicular phase of the cycle may indicate that estrogen levels might have an influence on dichotic listening in women.

Condições de trabalho e de voz em professores de escolas públicas e privadas

RESUMO Objetivo Identificar se existe correlação entre o Índice de Triagem para Distúrbio de Voz e as condições de trabalho de professores das escolas públicas e privadas e compará-las entre os professores das duas redes de ensino. Métodos Participaram 183 professores, sendo 122 de escolas públicas e 61 de uma escola privada, que responderam ao questionário Condição de Produção Vocal do Professor, composto por 81 questões. Destas, entretanto, foram analisadas as questões referentes à identificação pessoal, funcional, condições vocais e de trabalho. Foi realizada análise estatística descritiva e inferencial. Resultados Quando analisados em relação às condições vocais, a maioria dos professores das escolas públicas relatou queixa vocal. O Índice de Triagem para Distúrbio de Voz dos professores das escolas públicas correspondeu a mais sintomas vocais do que os da escola privada. Além disso, os docentes das escolas públicas relataram piores condições de trabalho, em relação aos docentes da escola privada. Conclusão Existe uma correlação negativa entre o Índice de Triagem para Distúrbio de Voz e as condições de trabalho dos professores de escola pública e particular. Os professores das escolas públicas relataram piores condições de trabalho do que os da escola privada, bem como referiram maior ocorrência de distúrbio da voz e apresentaram maior pontuação no Índice de Triagem para Distúrbio de Voz.

Eugenia uniflora Dentifrice for Treating Gingivitis in Children: Antibacterial Assay and Randomized Clinical Trial

Abstract School-age children are frequently at high risk for the onset of biofilm-dependent conditions, including dental caries and periodontal diseases. The objective of this study was to evaluate the clinical efficacy of a dentifrice containing Eugenia uniflora Linn. (Surinam cherry) extract versus a triclosan-based comparator in treating gingivitis in children aged 10-12 years. The in vitro antibacterial potential of the dentifrice was tested against oral pathogens (Streptococcus mutans, Streptococcus oralis and Lactobacillus casei). Then a phase-II clinical trial was conducted with 50 subjects aged 10-12 years, with clinical signs of gingivitis. The subjects were randomly assigned to the experimental group (n=25) and control group (n=25), in which participants used the experimental dentifrice and a triclosan-based fluoridated dentifrice (Colgate Total 12(r)), respectively. Clinical examinations assessed the presence of gingivitis (primary outcome) and biofilm accumulation (secondary outcome) using the Gingival-Bleeding Index (GBI) and Simplified Oral Hygiene Index (OHI-S), respectively, at baseline and after seven days of tooth brushing 3x/day. The data were analyzed using paired and unpaired t-test (GBI) and Wilcoxon and Mann-Whitney (OHI-S), with p≤0.05. The experimental dentifrice showed efficient antibacterial activity in vitro. In the clinical trial, a significant reduction in gingival bleeding was observed in both experimental and control groups (p<0.0001), with no statistical difference between them (p=0.178), although a small size effect was observed. Biofilm accumulation was only reduced in the control group (p=0.0039). In conclusion, E. uniflora dentifrice showed anti-gingivitis properties in children aged 10-12 years. Thus, it may be a potentially efficient and safe product to be used alternatively in preventive dental practice

Dentin reactions to caries are misinterpreted by histological "gold standards"

Dentin reactions to caries, crucial for pathogenesis and for the determination of the severity of caries lesions, are believed to be reasonably detected by stereomicroscopy (SM) and polarized light microscopy in quinoline (PLMQ), but accuracies are not available. Here, stereomicroscopy of wet (SW) and dry (SD) ground sections of natural occlusal caries lesions resulted in moderate (0.7, for normal dentin) and low accuracies (< 0.6, for carious and sclerotic dentin) as validated by contrast-corrected microradiography. Accuracies of PLMQ were moderate for both normal (0.71) and carious dentin (0.71). The hypothesis that detection of dentin reactions by SM and PLMQ would be influenced by the contrast quality of micrographic images was rejected. Dentin reactions were scored by SW, SD, PLMQ, and three types of microradiographic images with varying contrast qualities and each technique was compared against the one that resulted in the highest number of scores for each dentin reaction. Large differences resulted, mainly related to the detection of sclerotic dentin by both SW and SD, and normal and carious dentin by PLMQ. It is concluded that contrast-corrected microradiography should be preferred as the gold standard and SM and PLMQ should be avoided, but the relationship of PLMQ with dentin mineralization deserves further investigation.