Subclinical concentrations of chlorhexidine inhibit gelatinase activity of carious dentine in vitro.

BACKGROUND: There is evidence that dentine matrix gelatinases are involved in the destruction of carious dentine after demineralization by bacterial acids. It has also been observed that chlorhexidine, in very low concentrations, inhibits the activity of these enzymes in mammalian cells. The goal of this study was to determine if the gelatinase activity of carious dentine may be inhibited by chlorhexidine in clinical use concentrations. METHODS: Gelatinolytic activity was evaluated through zymography and identified by Western blot. The inhibitory effects of chlorhexidine at concentrations of 0.01%, 0.04%, 0.08% and 1% on the enzymatic activity of softened carious dentine samples were determined. RESULTS: In carious dentine, five bands of gelatinolytic activity were detected, with molecular sizes of 86, 75, 38, 33 and 32 kDa. The two bands of the greatest molecular size corresponded to latent and active metalloproteinase-9, respectively. Concentrations of chlorhexidine that were greater than or equal to 0.04% were sufficient to inhibit gelatinolytic activity in the observed bands of carious dentine. CONCLUSIONS: These results support the use of chlorhexidine in clinical use concentrations for the treatment and control of dentine caries. Our study demonstrates for the first time the inhibitory effect of chlorhexidine on gelatinases from carious human dentine.

Estudio de confiabilidad de la prueba de sialometría para flujo no estimulado en sujetos adultos clínicamente sanos / Study of reliability of the sialometry test for non-stimulated flow in clinically healthy adult individuals

Introducción: En personas sanas, la velocidad de flujo salival o sialometría (VFS) puede afectarse por la edad, género y ritmo circadiano. No existe evidencia de la reproducibilidad de VFS no estimulada determinada en 5 minutos, en distintos momentos del día en un mismo individuo. Objetivos: Determinar confiabilidad de VFS no estimulada medida en 5 minutos, reproducibilidad en el tiempo y relación con rango etario y género. Metodología: Se determinó VFS durante 15 minutos en 42 individuos clínicamente sanos, con una mediana de 45.5 (30-65) años, entre 9 y 11 AM durante dos mañanas y entre 3 y 5 PM durante la tarde del segundo día de medición. La saliva se colectó en tubos separados durante 5 minutos y durante los 10 minutos restantes. El peso de las muestras fue expresado en ml/min. Los valores entre los grupos de estudio, se compararon mediante test t de Student, ANOVA y coeficiente de correlación de Spearman. Resultados: VFS promedio fue de 0.623 +/- 0.329 y de 0.551 +/- 0.289 a los 5 y 15 minutos respectivamente (p=0.001). VFS fue mayor en hombres a los 5 y 15 minutos (p=0.001). VFS en mujeres, disminuyó al aumentar la edad. No hubo diferencias en VFS a los 5 minutos (p=0.375) y a los 15 minutos (p=0.825), en distintos días y momentos del día, en un mismo individuo. Conclusión: VFS colectada durante 5 minutos, en un mismo individuo, presenta valores constantes en distintos días y momentos del día.

Introduction: In healthy persons, the salivary flow rate (VFS) or sialometry can be affected by the age, the gender and the circadian rhythm. There is no evidence of the reproducibility of the non-stimulated VFS determined in 5 minutes, in different moments of the day in the same individual. Aim: To determine the reliability of the non-stimulated VFS measured in 5 minutes, its reproducibility over time and its relation with the age range and the gender. Methodology: VFS was determined for 15 minutes in 42 clinically healthy individuals, with a median age of 45.5 (30-65), between 9 and 11 AM in two mornings and between 3 and 5 PM in the evening of the second day of measurement. The saliva was collected in 2 separated pipes, one for the first 5 minutes and one for the 10 remaining minutes. The weight of the samples was expressed in ml/min. The values between the groups of study were compared by means of the Student’s t-test, ANOVA and the Spearman’s correlation coefficient. Results: The average VFS was of 0.623 +/- 0.329 and of 0.551 +/- 0.289 after 5 and 15 minutes respectively (p=0.001). VFS was higher in men after 5 and 15 minutes (p=0.001). VFS in women diminished as the age increased. There were no differences in VFS after 5 minutes (p=0.375) and after 15 minutes (p=0.825), in different days and moments of the day, in the same individual. Conclusion: VFS collected for 5 minutes in the same individual presents constant values in the different days and moments of the day.