A preliminary study of saliva matrix metalloproteinases (MMP-2 and MMP-9) in children with caries / 北京大学学报(医学版)

OBJECTIVE@#To investigate the correlation between matrix metalloproteinase (MMP)-2/MMP-9 levels and childhood caries, and the saliva levels of MMP-2/MMP-9 among healthy children and those with different degrees of dental caries, both before and after treatment.@*METHODS@#In the study, 368 children aged 3 to 5 years were separated into three groups: severe caries group (112 children), mild caries group (98 children) and caries free group (158 children). The children with severe caries were included in treatment group (83 children) after accepting a comprehensive treatment of caries. MMP-2 and MMP-9 levels were determined by enzyme-linked immunosorbent assay (ELISA) and the data were analyzed by the Statistics Package for Social Science (SPSS 13.0). The differences among severe caries group, mild caries group and caries free group were analyzed by SNK-q (Student Newman Keuls). The severe caries group and treatment group were compared by paired t test. The differences between each group were statistically analyzed.@*RESULTS@#There was no significant difference of the age and gender composition among severe caries group, mild caries group, caries free group and treatment group. The MMP-2 level of severe caries group [(141.3±32.5) μg/L] was higher than those of mild caries group [(107.5±21.3) μg/L] and caries free group [(102.8±18.5) μg/L] (P<0.05). There was no significant difference between mild caries and caries free group (P>0.05). After analysis of 83 children in the treatment group, the level of MMP-2 [(120.1±24.8) μg/L] was lower than before [(144.6±30.3) μg/L] (P<0.05), but was higher than that of caries free group (P<0.05). The MMP-9 levels of severe caries group [(445.8±68.1) μg/L] and mild caries group [(428.6±59.2) μg/L] were higher than that of caries free group [(385.4±60.6) μg/L] (P<0.05), but the difference between severe caries group and mild caries group was not significant (P>0.05). After analysis of 83 children in the treatment group, the alteration of MMP-9 [(432.2±64.7) μg/L] was not significant either (P>0.05).@*CONCLUSION@#The saliva levels of MMP-2 and MMP-9 in children with severe caries were higher than those in caries free children, even if the treatment was implemented, which suggests that the MMP-2 and MMP-9 in saliva might be related to the caries in children.

Caries-free subjects have high levels of urease and arginine deiminase activity

Objectives: This study investigated the relationship between urease and arginine deiminase system (ADS) activities and dental caries through a cross-sectional study. Material and Methods: Urease and ADS activities were measured in saliva and plaque samples from 10 caries-free subjects and 13 caries-active. Urease activity was obtained from the ammonia produced by incubation of plaque and saliva samples in urea. ADS activity was obtained from the ammonia generated by the arginine-HCl and Tris-maleate buffer. Specific activity was defined as micromoles of ammonia per minute per milligram of protein. Shapiro-Wilk statistical test was used to analyze the distribution of the data, and Mann-Whitney test was used to determine the significance of the data. Results: The specific urease activity in saliva and plaque was significantly higher in individuals with low DMFT scores. ADS activity in saliva (6.050 vs 1.350, p=0.0154) and plaque (8.830 vs 1.210, p=0.025) was also higher in individuals with low DMFT scores. Conclusions: Caries-free subjects had a higher ammonia generation activity by urease and arginine deiminase system for both saliva and plaque samples than low caries-active subjects. High levels of alkali production in oral environment were related to caries-free subjects. .

Production of glucosyltransferase B and glucans by streptococcus mutans strains isolated from caries-free individuals

La glucosiltranferasa B es una enzima producida por Streptococcus mutans, que a partir de la sacarosa, cataliza la síntesis de glucanos insolubles los cuales dan soporte a la biopelícula, siendo uno de los principales factores de virulencia para la generación de la caries dental. Sin embargo, no se ha esclarecido su papel en los individuos libre de caries, portadores delmicroorganismo. El objetivo de este estudio fue determinar la producción de glucosiltransferasa B y la producción de glucanos por cepas de Streptococcus mutans aisladas de biopelícula de 30individuos libres de caries. Las cepas fueron cultivadas en caldo Todd Hewitt y las proteínas extracelulares fueron obtenidas por precipitación con sulfato de amonio las proteínas asociadas amembrana por extracción con urea. La presencia de GtfB fue determinada por peso molecular por SDS–PAGE, confirmada por Western Blot utilizando un anticuerpo específico y la producciónde polisacáridos por separación electroforética, incubación con sacarosa y coloración de Schiff. Los resultados muestran que el 96.7 por ciento de las cepas de Streptococcus mutans producen una banda a la altura del peso molecular correspondiente a las Gtf,de las cuales son reactivas por western blot el 63.4 por ciento El 93.3 por cientode las cepas producen polisacáridos. Conclusiones: la cepas de Streptococcus mutans aisladas de biopelícula de individuos sanos producen factores de virulencia asociados a la caries dental como glucosiltransferasa B y glucanos lo que indica que hay condiciones en la cavidad oral diferentes a estos factores que mantienen al individuo libre de caries dental, los cuales deben ser investigados en la búsqueda de estrategias para controlar la enfermedad.

Acción antimicrobiana in vitro de la miel de abejas sobre los microorganismos cariogénicos estreptococos del grupo mutans / In vitro antimicrobial activity of honey on mutans streptococci

En el presente estudio fue evaluada la actividad antimicrobiana in vitro de cuatro muestras de mieles producidas en nuestro país, sobre los recuentos de estreptococos del grupo mutans, en escolares con alto riesgo de caries dental. Se obtuvieron muestras de saliva de 20 escolares, con edades entre 12 y 14 años, pertenecientes a la ciudad de Temuco, Región de La Araucanía (Chile). El recuento de estreptococos del grupo mutans en saliva fue estimado por el método microbiológico semi-cuantitativo Linoscreen®. La evaluación de la acción antibacteriana de la miel se realizó en 9 escolares que presentaron los recuentos más elevados de estreptococos del grupo mutans, utilizando concentraciones de miel entre 5 por ciento y 35 por ciento. Los datos mostraron que el 100 por ciento de los niños analizados poseían colonias de estreptococos del grupo mutans en su saliva. Además, se verificó que el 45 por ciento (9/20) de los escolares se encontraba en la categoría de alta actividad cariogénica. Con este estudio, también se comprobó que la miel de abejas posee actividad antimicrobiana sobre las bacterias estreptococos del grupo mutans y que no existían diferencias significativas entre las 4 mieles utilizadas, con relación a su capacidad antibacteriana (p>0.05). Por otra parte, este estudio también permitió demostrar que a mayor concentración de miel utilizada mayor era la reducción de las bacterias cariogénicas. En conclusión, en el presente estudio se demostró la acción antimicrobiana in vitro de la miel sobre los recuentos de bacterias cariogénicas estreptococos del grupo mutans. Sin embargo, serán necesarios futuros estudios para identificar y evaluar los componentes de la miel de abejas, responsables de esta propiedad.

The aim of the present issue was to evaluate the antibacterial activity of four commercial honeys against mutans streptococci in schoolchildren with high risk of caries development. We have investigated 20 schoolchildren from Temuco city (Chile), aged 12 -14 years. Saliva samples were obtained by stimulation with solid paraffin. The count of mutans streptococci in saliva was estimated by microbiological method. The antimicrobial activity of honey was evaluated by dilution in TYCBS medium in 9 schoolchildren (> 500.000 cfu/mL). Four concentrations of honey were used ranging from 5 to 35 percent. The presence of S. mutans was detected in 100 percent of schoolchildren. Our data shown that honey present high antimicrobial activity against S. mutans, being the dilutions at 30 and 35 percent that shown the better inhibitory effect (p<0.001). No differences between 4 honeys in relation to antibacterial activity were observed (p>0.05). In conclusion, our data showed that honeybees present in vitro antibacterial activity against S. mutans. However, future studies are necessary to characterize the honey components, responsible for this property.

Relation of salivary inorganic phosphorus and alkaline phosphatase to the dental caries status in children.

The phosphorus concentration and alkaline phosphatase activity in saliva may be related to the susceptibility to dental caries. Thirty children in the age group of 4-6 years were divided into 3 groups. Group 1, children had rampant caries with dfs>10, group 2- dfs>5<10, group 3 caries free with dfs<1. The unstimulated mixed salivary sample was collected from each child and assayed by biochemical methods to determine the phosphorus and alkaline phosphatase concentration in saliva sample. The results showed that higher alkaline phosphatase activity and phosphorus concentration were associated with rampant caries.