ABSTRACT: Introduction: Sodium hypochlorite and ultrasonic activation have a synergistic and improving effect on canal disinfection. Some authors found irrigant decrease after activation with ultrasonic, while others described an increased concentration in later stages. The aim of this study was to determine if activation of sodium hypochlorite by passive ultrasonic irrigation reduces its concentration compared to a technique without activation. Materials and methods: A ex-vivo descriptive study was conducted with teeth, randomized into two groups: 10 controls and 20 experimental. The hypochlorite of groups undergoing endodontic treatment was collected, and the post-irrigation residual with saline was gathered. The activation by ultrasonic was performed in stage 4.5 with Ultrasonic Scaler NSK®, three cycles of 20 seconds each per tooth. Irrigant concentration was measured by spectrophotometry. Results. In the first 4 stages, there were no concentration differences between groups. Stage 4.5 demonstrated a significant difference between the treated and control group. At saline irrigation stages, there was only a significant difference in stage E5. When activation was performed, the sodium hypochlorite curve maintained concentration values close to 5% in more stages in comparison to the control group. Conclusions: Passive ultrasonic activation demonstrated higher significant concentration of sodium hypochlorite, compared to a technique without activation.

ABSTRACT: One of the most effective and studied measures in the prevention of caries is the use of fluoride, which has the property to reduce their incidence and severity. In Chile, 75 % of the population receives it the drinking water. In 1984, WHO recommended the use of milk as an alternative vehicle. In Chile, the Fluoridated School Feeding Program (FSFP) was introduced in 1994, using this alternative in rural areas without fluoride in water. The objective of the study was to compare prevalence and severity of dental caries and dental fluorosis in 8-year-old children of four state schools: two with fluoride supplementation in drinking water or milk and two without any fluoride program. Epidemiological, descriptive, comparative, observational and cross-sectional study with a sample of 140 8-year-old children, with no systemic diseases and who had lived in the same place since birth: 50 schoolchildren from an area with fluoridated water; 40 from an area with fluoridated milk and 50 from a zone without supplementation of F. The percentage of caries-free children was obtained with the methodology described by the WHO, for severity the dmft and DMFT indexes were used. To quantify the prevalence and severity of dental fluorosis, Dean Index was used. 38 % of the children were caries-free in the community with fluoridated water (CFW); 0 % in the community with fluoridated milk (FSFP) and 10 % in the community with no fluoride program established (CNF). The difference between CFW with CNF is statistically significant (p<0.05). The prevalence of fluorosis is significantly higher for CFW (48.8 %) than FSFP (35 %) and CNF (16 %). Conclusion: The contribution of fluoride in drinking water causes a decrease in the prevalence and severity of dental caries in children of 8 years of age, and an increase in the prevalence of dental fluorosis.

RESUMEN: Una de las medidas más efectivas y estudiadas en la prevención de caries es el uso de fluoruros, que tiene la propiedad de reducir su incidencia y severidad. 75 % de la población chilena lo recibe al incluirlo en el agua potable. La OMS en 1984 recomendó el uso de leche como un vehículo alternativo. En Chile, el Programa de Alimentación Escolar con leche fluorada fue implementado en 1994 como alternativa en zonas rurales sin fluoruro en el agua. El objetivo de este estudio fue comparar la prevalencia y severidad de la caries dental y la fluorosis dental en niños de 8 años en tres escuelas públicas, con suplementación de fluoruro en el agua potable o en la leche y con aquella que no tiene ningún programa de fluoración. Estudio epidemiológico, descriptivo, comparativo, observacional y de corte transversal con una muestra de 140 niños de 8 años, sin enfermedades sistémicas y que han vivido en el mismo lugar desde su nacimiento: 50 escolares en el área con agua fluorada, 40 en el área con leche fluorada y 50 en la zona sin suplementación de fluoruro. El porcentaje de niños libres de caries fue obtenido con la metodología descrita por la OMS, usando índices ceo-d y CPO-D para evaluar severidad. Para cuantificar la prevalencia y severidad de la fluorosis dental se ocupó el índice de Dean. Niños libres de caries fueron 38 % en la comunidad con agua fluorada (CWF); 0 % en la comunidad con leche fluorada (FSFP) y 10 % en la comunidad sin programa de fluoración (CNF). La diferencia entre CWF y CNF es estadísticamente significativa (p<0,05). La prevalencia de fluorosis es significativamente mayor en CWF (48,8 %) que FSFP (35 %) y CNF (16 %). La contribución del fluoruro en el agua potable causa una disminución en la prevalencia y severidad de la caries dental en niños de 8 años, y un aumento en la prevalencia de fluorosis dental.

RESUMEN. Introducción: el objetivo del presente estudio consistió en implementar la técnica de qPCR en tiempo real para identificar y cuantificar la especie Streptococcus mutans en muestras de saliva y biopelícula dentaria. Métodos: se seleccionaron al azar 27 niños de 8 años de edad, de nivel socio-económico bajo del área norte de la región metropolitana de Santiago de Chile, que se citaron en ayunas y sin cepillado durante al menos 12 horas, para colectar saliva no estimulada y un pool de biopelícula dentaria supragingival de todas las caras mesio-vestibulares de dientes anteriores y posteriores. Se cuantificó la cantidad de S. mutans en las muestras mediante qPCR empleando partidores que amplifican un fragmento del gen gtfB de S. mutans. Resultados: la amplificación presentó 98% de eficiencia con delta de fluorescencia de 3,36 ciclos. La curva de fusión (melting) presentó un solo máximo a una misma temperatura para todas las muestras. Conclusión: la metodología permite la identificación y cuantificación específica del gen gtfB de S. mutans en muestras de saliva y biopelícula dentaria, de forma rápida y exacta, aportando a la determinación del riesgo cariogénico individual.

ABSTRACT Introduction: the objective of this study was to use real-time qPCR to identify and quantify the Streptococcus mutans species in samples of saliva and dental biofilm. Methods: 27 children were randomly chosen with the following criteria: 8 years of age, low socio-economic levels, residing in the northern metropolitan area of Santiago de Chile; they were asked to attend an appointment while fasting with no teeth brushing for at least 12 hours, in order to collect non-stimulated saliva and a pool of supragingival dental biofilm of all the mesio-vestibular sides of anterior and posterior teeth. The amount of S. mutans in the samples was quantified by qPCR using primers that amplify a fragment of the gtfB gene of S. mutans. Results: the amplification showed 98% efficiency with a fluorescence of 3.36 cycles. The melting curve presented a single maximum at the same temperature for all samples. Conclusion: the methodology allows the specific identification and quantification of gene gtfB of S. mutans in saliva and dental biofilm in a quick and reliable manner, contributing to the identification of individual cariogenic risk.

Introduction Chlorhexidine (CHX) in aqueous solution is hydrolysed to p-chloroaniline (PCA), a process accelerated by increasing temperature and pH. Using endodontic ultrasound based on oscillation phenomena, cavitation, and acoustic microstreaming generates heat, affecting the CHX. Objective The aim of this in vitro study was to identify and quantify the physical-chemical changes, temperature and pH, and the amount of PCA formed by increasing the temperature of 2% CHX by endodontic ultrasound. Materials and methods Samples of 2% CHX were activated for 30, 60, 90, and 120 seconds with endodontic ultrasound 24,500 Hz. The pH and temperature were measured before and after activation, as well as the formation and amount of PCA, by reading and recording the result obtained from a standard calibration curve reading at 375 nm in a UV-visible light spectrophotometer. Results Independent of time, ultrasound increased the temperature of 2% CHX by 1 °C and acidified the solution. No significant changes were recorded in pH and temperature. No staining or precipitates were observed in samples ultrasonically activated at different times. Samples read at 375 nm showed no measurable PCA values. Absorption spectra of 2% CHX and 2% CHX activated for more than 60 seconds showed different spectral curves, peaks, and absorbance values. Conclusions Ultrasound increased the temperature and acidified the solution of CHX for all application times. No PCA was detected by visible spectrophotometry. Absorption spectra of 2% CHX activated with ultrasound at different times differs from 2% CHX without activation. These differences indicate degradation of CHX and possible presence of PCA.

Introducción La clorhexidina (CHX) en solución acuosa se hidroliza generando paracloroanilina (PCA), proceso acelerado por el aumento de temperatura y pH. El uso de ultrasonido endodóntico (USE), basado en fenómenos de oscilación, cavitación, microcorriente acústica, genera calor afectando la CHX. Objetivo Identificar y cuantificar in vitro cambios fisicoquímicos, temperatura y pH, y la cantidad de PCA formada con el uso de ultrasonido endodóntico sobre soluciones de CHX al 2%. Materiales y métodos La CHX 2% se activó durante 30, 60, 90 y 120 seg con USE a 24.500 Hz, midiendo antes y después de activación: pH, temperatura y cantidad de PCA, leyendo a 375 nm en curva de calibración de estándares de PCA y formación, registrando el espectro de absorción mediante espectrofotómetro UV-visible. Resultados El USE aumentó la temperatura en 1 °C independiente del tiempo de aplicación y acidificó la solución de CHX 2%, sin variaciones significativas en pH y temperatura. No se observó coloración ni formación de precipitado en muestras activadas por USE a los diferentes tiempos. Las muestras no presentaron valores medibles de PCA a 375 nm. Los espectros de absorción de CHX 2% y activadas por USE por más de 60 seg presentaron curvas espectrales, peaks y valores de absorbancia diferentes. Conclusiones El USE aumenta la temperatura y acidifica la solución de la CHX en todos los tiempos de aplicación. No se detectó presencia de PCA por espectrofotometría visible. Muestras activadas por USE por 60 seg o más presentan espectros de absorción diferentes a las muestras sin activar. Diferencias en los espectros de absorción entre CHX activadas con USE y con CHX sin activar indicarían degradación de la CHX y posible presencia de PCA.

This study determined if p-chloroaniline (PCA) can be minimized by using distilled water and physiological saline solution following sodium hypochlorite but before chlorhexidine. Hypochlorite 5%, 0.5%, 0.05%, 0.005% and 0.0005% dissolved in 0.9% NaCl and in distilled water were mixed with 2% chlorhexidine for the formation of PCA. The PCA was determined using UV-VISIBLE spectrometry, with spectral curve was determined the wavelength of maximum absorption of PCA. Formed PCA absorbance was measured between 0.025%, 0.02%, 0.015%, 0.01%, 0.005% and 0.0025% hypochlorite and 2% chlorhexidine. 2% chlorhexidine and hypochlorite with physiological saline form a white precipitate which prevents the measurement of PCA. Colored PCA is formed with 0.05%, 0.005% hypochlorite aqueous dilutions and 2% chlorhexidine. The lwavelength of maximum absorption obtained was 470 nm and absorbance of PCA showed a linear decrease. 0.005% NaClO produces the least amount of PCA. The best solvent to prevent the formation of PCA during the interaction of sodium hypochlorite with chlorhexidine is distilled water.

Este estudio determinó si la p-cloroanilina (PCA) puede ser minimizada mediante el uso de agua destilada y solución salina fisiológica seguido de la aplicación de hipoclorito de sodio, previo a la aplicación de clorhexidina. Hipoclorito al 5%, 0,5%, 0,05%, 0,005% y 0,0005% fue disuelto en 0,9% de NaCl y en agua destilada se mezcló con 2% de clorhexidina para la formación de PCA. El PCA se determinó mediante espectrometría UV-Visible, y con curva espectral se determinó la longitud de onda máxima del PCA. La absorbancia del PCA formado se midió con 0,025%, 0,02%, 0,015%, 0,01%, 0,005% y 0,0025% de hipoclorito y 2% de clorhexidina. La combinación de 2% de clorhexidina e hipoclorito en solución salina fisiológica forman un precipitado blanco que impide la medición del PCA. El PCA coloreado es formado con 0,05%, 0,005% diluciones acuosas de hipoclorito y 2% de clorhexidina. La longitud de onda máxima obtenida fue de 470 nm y la absorbancia del PCA mostró una disminución lineal. NaClO al 0,005% produce menor cantidad de PCA. El mejor disolvente para evitar la formación de PCA durante la interacción de hipoclorito de sodio con clorhexidina es agua destilada.

OBJETIVO: Avaliar o dano e a prevalência de cárie e fluorose em crianças e adolescentes na região metropolitana do Chile, após oito anos de fluoretação da água potável, em comparação com o estudo de base em 1996. METODOLOGIA: Desenho: estudo de prevalência. A amostra probabilística, estratificada por nível socioeconômico, constituiu-se de 2.323 escolares de 6-8 e 12 anos na Região Metropolitana. Todos os alunos foram clinicamente examinados por dentistas calibrados, utilizando critérios de seleção e indicadores propostos pela OMS para determinar cárie e fluorose dentária. RESULTADOS: Cerca de 24% das crianças estavam livres de cáries. A média de CPOD foi de 3,18 em escolares de 6 a 8 anos. O CPOD foi de 0,59 em crianças de 6 a 8 anos e de 2,6 em crianças de 12 anos em relação ao estudo de base, sendo essas diferenças estatisticamente significativas. Houve diferenças significativas devido ao nível socioeconômico, sendo que os valores médios foram maiores em crianças de baixo nível socioeconômico. Cerca de 14% das crianças apresentaram fluorose dentária, em geral de grau muito leve. CONCLUSÃO: Após 8 anos de fluoretação da água potável na região metropolitana, observou-se um aumento de 100% de crianças sem história de cárie e significativa diminuição de danos. A fluorose dentária aumentou, mas em graus mais leves.

PURPOSE: To assess the damage and the prevalence of caries and fluorosis in children and adolescents in the metropolitan area after 8 years of drinking water fluoridation and to compare them with the baseline study. METHODS: This was a prevalence study. The sample was selected using two-step probability sampling and stratified according to socioeconomic level. Subjects included 2,323 schoolchildren aged 6 to 8 years and 12 years living within the metropolitan region. The parents of all students provided consent and were previously included in the study. The subjects were clinically examined by calibrated dentists, who used World Health Organization (WHO) screening criteria and indicators to determine the presence of caries and dental fluorosis. RESULTS: No cavity damage was found in 23.68% of the children. The average dmft was 3.18 for children aged 6 to 8 years. The DMFT was 0.59 in children aged 6 to 8 years and 2.6 in children 12 years compared with the baseline study. These differences were statistically significant. There were also significant differences in the DMFT index for each socioeconomic status group. The average number of dams was higher among children of low socioeconomic status. Of the studied children, 14.3% of children had dental fluorosis. Fluorosis was very mild in 12.35% of the cases, mild in 1.98% and moderate in 0.26%. There were no cases of severe fluorosis (classified according to Dean's index). CONCLUSION: We conclude that after 8 years drinking water fluoridation in the metropolitan area, the number of children with no history of caries has increased by approximately 100%. The number of cases significantly affected by caries has also decreased significantly. The incidence of dental fluorosis has increased, but to milder degrees.

OBJETIVO: Avaliar a condição periodontal e as necessidades de tratamento de crianças escolares chilenas. METODOLOGIA: Estudo de prevalência. Amostra: 1637 crianças escolares de 6 a 8 anos de idade pertencentes a 26 comunidades da região metropolitana de Santiago, Chile, que foram estratificadas de acordo com o nível socioeconômico conforme o levantamento 2003 CASEN (National Socioeconomic Characterization Survey). A condição periodontal foi estimada usando o índice Community Periodontal Index of Treatment Needs (CPITN) e seguindo as recomendações da Organização Mundial de Saúde (OMS), juntamente com os registros de critérios clínicos de inflamação gengival. Os dados foram analisados por testes qui-quadrado. RESULTADOS: A prevalência de gengivite foi de 68,42%, resultado que é maior que a prevalência nacional do Chile (P<0,01; 95% CI=0,66-0,70). A prevalência aumentou com a idade (P<0,01), mas foi similar em ambos os sexos (P=0,838). A prevalência foi relativamente constante entre os três níveis socioeconômicos (P=0,417). Para CPITN, a prevalência de gengivite foi de 29,57%: 27,49% com sangramento gengival e 2,08% s com cálculo gengival. As necessidades de tratamento desta população foram de 27,49% de crianças que necessitavam de instrução de higiene bucal e 2,08% que necessitavam de instrução de higiene bucal e raspagem supra e subgengival. CONCLUSÃO: A prevalência de gengivite neste estudo foi maior que a proporção nacional no Chile.

PURPOSE: To evaluate the periodontal status and the treatment needs of Chilean school-children METHODS: Prevalence study. Sample: 1,637 schoolchildren from 6 to 8 years old belonging to 26 communes of the Santiago Metropolitan Region of Chile, stratified according to socioeconomic level in accordance with the 2003 CASEN survey (National Socioeconomic Characterization Survey). Periodontal status was estimated using the Community Periodontal Index of Treatment Needs (CPITN) and following the recommendations of the WHO (World Health Organization), along with the records of the Clinical Criteria of Gingival Inflammation. Data were analyzed using a chi-square test. RESULTS: Gingivitis prevalence was 68.42%, a result that is higher than the national prevalence (P<0.01; 95% CI=0.66-0.70). The prevalence increased with age (P<0.01) but was similar in both sexes (P=0.838). Prevalence was relatively constant among three socioeconomic levels (P=0.417). According to the CPITN, gingivitis prevalence was 29.57%: 27.49% consisting of children with gingival hemorrhage and 2.08% consisting of children with gingival calculus. The treatment needs of this population are that 27.49% of children require oral-hygiene instruction, and 2.08% need oral-hygiene instruction and subgingival and supragingival scaling. CONCLUSION: The gingivitis prevalence found in this study was higher than the national proportion in Chile.

OBJETIVO: Determinar a ingestão de flúor em pré-escolares de três a cinco anos de idade, de duas comunidades de Santiago, Chile, sendo uma com abastecimento público de água não fluoretada e outra com água fluoretada. METODOLOGIA: Estudo observacional, transversal. A amostra foi composta de 200 crianças de três a cinco anos de idade, com boa saúde geral, de baixo nível socioeconómico, que frequentavam quatro jardins de infância da Região Metropolitana de Santiago, Chile. Duas escolas estavam localizadas em Maipú, que não tem água pública fluoretada e duas escolas estavam localizadas em Peñalolén, com água fluoretada desde 1996, em uma concentração de flúor de 0,6 mg/L. A ingestão de flúor foi medida em uma amostra de urina da manhã, medindo-se o flúor com eletrodo íon-específico e concentração de creatinina com o produto comercial VALTEK (R). A ingestão de flúor estimado de outros veículos foi avaliada por questionários aos pais e educadores. RESULTADOS: A dose diária de ingestão de flúor (DDI) para todos os pré-escolares Maipú foi 0,021 mg F/kg peso corporal (pc)/dia, um valor menor do que a dose ideal de flúor, de 0,05 para 0,07 mg F/kg corporal/dia. Na amostra de Peñalolen a DDI atingiu 0.066 mg F/kg corporal/dia, dentro dos parâmetros ideais. Houve cerca de 0,019 mg F/kg bw/dia em Maipú e 0.017 mg F/kg corporal/dia em Peñalolén proveniente da ingestão de creme dental com flúor. A frequência de escovação diária foi de 3,15 vezes, sendo que 31% das crianças de Maipú e 33% das crianças Peñalolen ingeriam creme dental. Cerca de 46,5% das crianças bebia chá todos os dias. A estimativa para a quantidade de ingestão de flúor do creme dental e consumo de chá explica a contribuição de flúor não proveniente de água fluoretada. CONCLUSÃO: A ingestão de flúor da água e outras fontes no município de Peñalolen pré-escolar é muito maior que a ingestão de flúor em pré-escolares do distrito de Maipú.

PURPOSE: To determine the fluoride intake in three- to five-year-old preschool children from two communes in Chile, one with a non-fluoridated public water supply (Maipú) and the other with fluoridated public water supply since 1996, at a fluoride concentration of 0.6 mg/L (Peñalolen). METHODS: Cross-sectional, observational design. The sample population was composed of 200 three-to-five-year-old children attending four kindergartens in the Santiago Metropolitan Region, Chile, in the communes of Maipú and Peñalolen. Intake of fluoride was measured in a morning urine sample by using an ion-specific electrode and creatinine concentration. The fluoride intake from other sources was estimated from the parents' and educators' survey answers. RESULTS: The daily dose of fluoride intake (DDI) for all Maipú preschoolers was 0.021 mg F/kg body weight (bw)/day, a value less than the optimal dose, which is 0.05 to 0.07 mg F/kg bw/day. The DDI for the Peñalolen sample reached 0.066 mg F/kg bw/day. There is a contribution from fluoride toothpaste ingestion of 0.019 mg F/kg bw/day in Maipú and 0.017 mg F/kg bw/day in Peñalolen. The overall frequency of daily brushing was 3.15 times, during which 31% of Maipú children and 33% of Peñalolen children ingested toothpaste. The estimated amount of fluoride intake from toothpaste and tea consumption explained the contribution of fluoride not coming from fluoridated water. CONCLUSION: The fluoride ingestion from water and other sources in the preschool commune of Peñalolen is much higher than the fluoride intake in preschoolers of the Maipú district.