Polarization of dental caries among individuals aged 15 to 18 years

OBJECTIVE: To evaluate the role of socioeconomic variables and self-perceived oral health in the polarization of caries among adolescents in Santa Bárbara D'Oeste, Brazil. MATERIAL AND METHODS: Cross-sectional study. Sampling was randomized and sample size was defined according to WHO criteria. Two hundred and seventy seven adolescents (15 to 18 year-old) were examined by five trained examiners that assessed DMFT index according to WHO criteria. Self-perceived oral health, access to dental services and socio-demographic variables were self-reported. Student's t tests, chi-square tests, and multivariate logistic regression (with significant caries index (SiC) as the outcome), were performed. RESULTS: Mean DMFT was 5.48 (±4.22) and the proportion of "caries free" subjects was 15.5%. Mean DMFT (9.71±2.85) and mean D (1.67±2.18) of SiC positive subjects were significantly higher than mean DMFT (2.88±2.17) and mean D (0.45±0.87) of SiC negative subjects (

S. mutans biofilm model to evaluate antimicrobial substances and enamel demineralization

The aim of this study was to validate a model of S. mutans biofilm formation, which simulated 'feast-famine' episodes of exposure to sucrose that occur in the oral cavity, showed dose-response susceptibility to antimicrobials and allowed the evaluation of substances with anticaries potential. S. mutans UA159 biofilms were grown for 5 days on bovine enamel slabs at 37°C, 10% CO2. To validate the model, the biofilms were treated 2x/day with chlorhexidine digluconate (CHX) at 0.012, 0.024 and 0.12% (concentration with recognized anti-plaque effect) and 0.05% NaF (concentration with recognized anti-caries effect). CHX showed dose-response effect decreasing biomass, bacterial viability and enamel demineralization (p < 0.05). Whereas, 0.05% NaF did not show antimicrobial effect but had similar effect to that of 0.12% CHX decreasing enamel demineralization (p < 0.05). The model developed has potential to evaluate the effect of substances on biofilm growth and on enamel demineralization

SOLUBILIDAD Y DUREZA SUPERFICIAL DE CERÁMICAS ODONTOLÓGICAS DESPUÉS DE SER EXPUESTAS A FLUIDO GÁSTRICO ARTIFICIAL. ESTUDIO IN VITRO

Enfermedades como reflujo gastroesof&aacute;gico y bulimia, provocan alteraciones &aacute;cidas en la cavidad bucal que pueden causar erosi&oacute;n dental. El efecto de este medio &aacute;cido sobre materiales restauradores y posibles cambios en sus propiedades son poco relatado en la literatura. De esta forma, el objetivo de este trabajo fue evaluar la solubilidad y la microdureza de cer&aacute;micas feldesp&aacute;ticas expuestas in vitro a fluido g&aacute;strico simulado sin enzimas (pH 1,2). Fueron confeccionados 100 discos, de 8mm de di&aacute;metro y 2mm de altura, con las siguientes cer&acirc;micas: Vitadur Alfa (I), Vita Omega 900 (II) Finesse All-Ceramic (III), IPS dSign (IV) y Carmen (V). Estos fueron divididos en tres grandes grupos seg&uacute;n la exposici&oacute;n al fluido g&aacute;strico: (A) sin exposici&oacute;n, (B) 24 horas de exposici&oacute;n y (C) 7 d&iacute;as de exposici&oacute;n. La solubilidad fue evaluada por medio del pesaje en balanza digital (Metler Toledo), calcul&aacute;ndose la cantidad de p&eacute;rdida de masa (MP). El an&aacute;lisis de microdureza Vickers (MD) fu&eacute; realizado utilizando un microdur&oacute;metro FM-700 (Future Tech). Los resultados obtenidos mostraron valores de p&eacute;rdida de masa (%) de B, comparado con A, de: 0,1280(I), 0,2143(II), 0,0485(III), 0,1377(IV), 0,0824(V); y para C de: 0,1182(I), 0,2305(II), 0,0773(III), 0,1653(IV), 0,3256(V). Se observaron valores de dureza superficial para A de: 527,53(I), 531,67(II), 519,85(III), 544,72(IV), 523,72(V); para B de: 505,38(I), 529,63(II), 478,60(III), 514,91(IV); 504,97; y C de: 484,96(I), 495,61(II), 493,5(III), 482,76(IV), 488,22(V). El an&aacute;lisis estad&iacute;stico con el test de ANOVA (p&lt;0,05), mostr&oacute; influencia del fluido g&aacute;strico tanto en la p&eacute;rdida de masa como en la solubilidad de las cer&aacute;micas evaluadas

Photoelastic evaluation of the effect of composite formulation on polymerization shrinkage stress

We compared polymerization stress in two commercial composites and three experimental composites made using camphorquinone (CQ) and/or phenylpropanedione (PPD) as photoinitiators. The internal surfaces of photoelastic resin discs with cylindrical cavities were roughened and treated with adhesive. Composites were divided into five groups: two commercial composites (Filtek Silorane and Filtek Z250) and three experimental composites with CQ/amine, CQ/PPD/amine, and PPD/amine. Composites were photopolymerized inside cavities, and subjected to photoelastic analysis immediately and at 24 hours and 7 days later using a plane polariscope. Stress created by Silorane (3.08 ± 0.09 MPa) was similar to that of Z250 (3.19 ± 0.13 MPa) immediately after photopolymerization (p > 0.05). After 24 hours and 7 days, Z250 (3.53 ± 0.15 and 3.69 ± 0.10 MPa, respectively) showed higher stress than Silorane (3.19 ± 0.10 and 3.16 ± 0.10 MPa, respectively). Qualitative analysis immediately after photopolymerization showed composite/CQ promoted higher stress than PPD, but stress levels at other evaluated times were statistically similar, varying between 3.45 ± 0.11 MPa and 3.92 ± 0.13 MPa. At 24 hours and 7 days, Silorane created the lowest stress. All photoinitiators created comparable tensions during polymerization