Influencia de un enjuague a base de fluoruro y xilitol en la remineralización in vitro del esmalte en dientes temporales / Influence exerted by a xylitol and fluoride based mouthwash on the in vitro enamel remineralization of primary teeth

El propósito del estudio fue evaluar la eficacia de un enjuague bucal con fluoruro de sodio y xilitol, en la remineralización del esmalte de dientes temporales. Se utilizaron 40 dientes sin caries, aplicando ácido fosfórico al 35% durante 20 segundos, y fueron inmersos en el enjuague por 0, 15, 30, 45 y 60 días. Se observaron cortes longitudinales de 150-250 µm de cada muestra y se valoró la remineralización, de acuerdo a la birrefringencia observada después de aplicarles solución de Thoulet (1.47 IR) bajo luz polarizada en un fotomicroscopio. A los 15 días tuvo una media de 0.444 (± 0.527), a los 30 días de 0.778 (± 0.441), a los 45 de 1.444 (± 0.527) y a los 60 días de 1.47 (± 0.483). El análisis de varianza permitió establecer diferencias estadísticamente significativas entre los grupos (p < 0.001), y comparándolos entre sí (p < 0.05). Puede concluirse que el enjuague empleado tuvo un ligero efecto remineralizante en el esmalte.

The purpose of the present study was to assess the effectiveness on primary teeth of a fluoride and xylitol based mouthwash. 40 caries-free teeth were used. 35% phosphoric acid was applied during 20 seconds. Teeth were then immersed in the mouthwash for 0, 15, 30, 45 and 60 days. 150-250μm longitudinal slices were taken of each sample. Re-mineralization was assessed according to bi-refringence observed after applying Thoulet solution (1.47 IR). Assessment was conducted under polarized light in a photo-microscope. At 15 days, a mean of 0.444 (± 0.527) was observed. After 30 days the observed mean was 0.778 (± 0.441). At 45 days, observed mean was 1.444 (± 0.527), and at 60 days, observed mean was 1.47 (± 0.483). Variance analysis established statistically significant differences among groups (p < 0.001) as well as when comparisons among groups were established (p < 0.05). After conducting the aforementioned tests it could be concluded that the employed mouthwash exerted a slight re-mineralizing effect upon the enamel of treated teeth.

Histological and microhardness evaluation of early artificial carious lesions in human and bovine enamel: in vitro study / Avaliação histológica e de microdureza de lesões incipientes de cárie em esmalte humano e bovino: estudo in vitro

Objective: Early carious lesions in bovine and human enamel developed in vitro using a pH cycling regimen were compared. Material and Methods: Fifteen central bovine incisors and fifteen recently extracted human third molars were randomly divided into two groups: ten for the cross-sectional microhardness test (MT) and five for polarized light microscopy (PLM) analysis. Enamel blocks measuring 5 x 5 mm were made from the buccal face of the teeth. The blocks used for the MT were sliced into two halves: “A” and “B”. “A” slices were embedded in acrylic resin, with the face of the dentin-enamel junction left exposed for the MT prior to pH cycling. “B” slices and whole blocks were coated with acid-resistant varnish, except a 3 x 3 mm central window, and submitted to the pH cycling regimen (demineralizing solution for 3 h and remineralizing solution for 21 h) over five consecutive days. The “B” slices were then submitted to the MT and the whole blocks were processed for the PLM study. Results: The PLM analysis revealed shallow, extensive lesions in the bovine enamel, hardly showing the superficial, dark and translucent zones, as well as deep cavity lesions in the human enamel, with the body of the lesion and the dark zone evident. The MT revealed a significant decrease in microhardness in the superficial levels of the bovine enamel caries and at all depth levels of the human enamel caries. Conclusion: The pH cycling regimen adopted led to the development of deeper and more demineralized carious lesions in human enamel than bovine enamel

Objetivo: Comparar lesões incipientes de cárie em esmaltes humano e bovino desenvolvidas in vitro através de ciclagem de pH. Material e Métodos: Quinze incisivos centrais bovinos e quinze terceiros molares humanos inclusos recém-extraídos foram aleatoriamente divididos em dois grupos: dez para o teste de microdureza tranversal (MT) e cinco para a análise por microscopia de luz polarizada (MLP). Blocos de esmalte com dimensões de 5 x 5 mm foram confeccionados a partir da face vestibular dos dentes. Os blocos utilizados para MT, a qual foi determinada em cinco níveis de profundidade, foram seccionados em duas metades, designadas por “A” e “B”. As fatias “A” foram submetidas ao teste de MT previamente à ciclagem de pH. Já as fatias “B” e os blocos de esmalte foram recobertos por verniz ácido-resistente, exceto por uma janela de 3 x 3 mm, e então submetidos à ciclagem de pH (soluções desmineralizadora por 3 h e remineralizadora por 21 h) por 5 dias consecutivos. As fatias “B” foram então submetidas a MT e os blocos foram processados para a MLP. Resultados: A análise por MLP revelou lesões rasas e extensas no esmalte bovino, com zonas superficial, escura e translúcida pouco visíveis; no esmalte humano, as lesões apresentaram-se profundas e cavitadas, com o corpo da lesão e a zona escura evidentes. A MT revelou significante diminuição na microdureza nos níveis superficiais do esmalte bovino e em todas as profundidades avaliadas do esmalte humano após a ciclagem de pH. Conclusão: A ciclagem de pH levou ao desenvolvimento de lesões de cárie mais profundas e com maior desmineralização no esmalte humano em comparação ao esmalte bovino.

Correlação entre a avaliação microscópica e a leitura por laser fluorescência de lesões de manchas brancas em dentes bovinos: estudo in vitro / Correlation between the microscopic evaluation and reading by laser fluorescence of enamel decalcification in bovine teeth: in vitro study

Objetivo: avaliar a correlação entre as leituras de descalcificação artificial de esmalte in vitro por meio do DIAGNOdent® e pela microscopia óptica com luz polarizada. Metodologia: foram utilizados 25 dentes bovinos que foram expostos a um meio artificial de cáries por uma hora, duas vezes ao dia, por 35 dias. Em seguida, procedeu-se as leituras das fluorescências utilizando o aparelho laser DIAGNOdent®. Foram registradas as leituras das áreas sem descalcificação (para calibração) e as áreas desmineralizadas artificialmente. Após as leituras da fluorescência, as regiões de leitura por laser foram cortadas em secções de aproximadamente 400μm e avaliadas por meio da microscopia de luz polarizada. Resultados: demonstraram que, embora com algum grau de variação, o sistema DIAGNOdent® foi capaz de detectar as descalcificações semelhantemente àqueles reconhecidos por microscopia de luz polarizada, estabelecendo um padrão razoável de equivalência de leituras. Conclusão: os valores médios encontrados para o DIAGNOdent® demonstraram um coeficiente de correlação de Pearson de 0,63 com relação aos valores das leituras microscópicas.

Aim: evaluate the correlation between the artificial in vitro enamel decalcification through DIAGNOdent® laser and through optic microscopic with polarized light. Methodology: for this research, 25 bovine teeth had been exposed to an artificial decay environment during one hour, two times a day, for 35 days. After wards, DIAGNOdent® laser has been used to read the fluorescence from the enemel areas without decalcification (for calibration) and to evaluate the non-mineralized artificially. After the fluorescence readings regions of laser read were cut into sections of about 400μm and evaluated by polarized light microscopy. Results: the results had demonstrated that, even with some degree of variation, the DIAGNOdent® system was capable of recognizing the decalcification, establishing regular equivalence of standard readings such as light polarized microscopy. Conclusion: the average values found for DIAGNOdent® laser had demonstrated a 0,63 coefficient of correlation of Pearson to the values of microscopically readings.