Inhibition of dentine collagen degradation by hesperidin: an in situ study.

Dentine caries is a process of demineralization and subsequent degradation of the collagenous matrix. Host-derived proteolytic enzymes, such as matrix metalloproteinases (MMPs), play a role in this process of dentine collagen degradation. Hampering this degradation retards the caries process. Dietary antioxidants, such as the flavonoid hesperidin, can inhibit the proteolytic activity of MMPs and act as natural stabilizers of collagen. The aim of this study was to investigate the anti-collagenolytic activity of hesperidin in an in situ model. A single-blind, split-mouth, in situ experiment was designed. Seventeen participants received two completely demineralized dentine specimens placed contralaterally in the buccal flanges of their partial prosthesis. During the 4-wk experimental period, the participants immersed the dentine specimens in a test solution [1,000 parts per million (p.p.m.) hesperidin] or a control solution (saline), twice daily for 3 min. After the in situ period, the specimens were retrieved and their collagen content was determined. A saliva sample was taken at the start and at the end of the experimental period, to assess collagenolytic activity. A significant protection of collagen, of 24%, was observed in the hesperidin-treated specimens compared with the control-treated specimens. No correlation was found between salivary collagenolytic activity and loss of collagen in the control-treated specimens. The results of this in situ study show that hesperidin could play a role in the preservation of dentine collagen matrix.

Comparative study of the measurement of enamel demineralization and remineralization using transverse microradiography and electron probe microanalysis.

Transverse microradiography (TMR) and electron probe microanalysis (EPMA) are commonly used for characterizing dental tissues. TMR utilizes an approximately monochromatic X-ray beam to determine the mass attenuation of the sample, which is converted to volume percent mineral (vol%min). An EPMA stimulates the emission of characteristic X-rays from a variable volume of sample (dependent on density) to provide compositional information. The aim of this study was to compare the assessment of sound, demineralized, and remineralized enamel using both techniques. Human enamel samples were demineralized and a part of each was subsequently remineralized. The same line profile through each demineralized lesion was analyzed using TMR and EPMA to determine vol%min and wt% elemental composition and atomic concentration ratio information, respectively. The vol%min and wt% values determined by each technique were significantly correlated but the absolute values were not similar. This was attributable to the complex ultrastructural composition, the variable density of the samples analyzed, and the nonlinear interaction of the EPMA-generated X-rays. EPMA remains an important technique for obtaining atomic ratio information, but its limitations in determining absolute mineral content indicate that it should not be used in place of TMR for determining the mineral density of dental hard tissues.

Cessation age of breast-feeding and pacifier use is associated with persistent finger-sucking.

PURPOSE: Although some studies have reported that breast-feeding and pacifier use influence finger-sucking, few have demonstrated whether the age at cessation of breast-feeding or pacifier use and persistent finger-sucking are related. Therefore, the purpose of this study was to examine whether the age at cessation of breast-feeding and pacifier use influenced persistent finger-sucking. METHODS: A cross-sectional study of 555 36- to 47-month-olds was conducted in Nagasaki, Japan, using a questionnaire. Using the optimal cutoff point in a receiver-operating characteristic curve, the age was estimated at which cessation of pacifier use and breast-feeding had the most significant effect on persistent finger-sucking, and the estimated ages were assessed by multiple logistic regression analysis, incorporating all the questions in the questionnaire as independent variables. RESULTS: The odds ratios for persistent finger-sucking when breast-feeding was stopped at an age younger than 12 months old or when pacifier use was stopped at an age younger than 14 months old were 3.77 (95 percent confidence interval (CI)=1.97-7.22) and 8.62 (95 percent CI=2.56-29.04), respectively. CONCLUSIONS: Cessation of breast-feeding before 12 months old or pacifier use before 14 months old was associated with persistent finger-sucking.

Effect of bamboo salt-NaF dentifrice on enamel remineralization.

PURPOSE: To evaluate the laboratory remineralization effects of a dentifrice with bamboo salt and NaF on artificial caries-like enamel lesions, at both the surface and deep areas. METHODS: Early dental caries lesions were formed by treating bovine enamel samples for 48 hours at 37 degrees C with a demineralization solution (pH 5.0) containing 0.1 M lactic acid, 0.2% Carbopol 907, and 50% saturated calcium phosphate tribasic. pH cycling was then performed by immersing the samples in dentifrice slurry for 2 minutes every 8 hours per day, and in demineralization solution for 4 hours and mixed saliva for the remaining time period. The mixed saliva consisted of 50% human saliva and 50% artificial saliva. The surface hardness and the level of mineral surface alterations were analyzed using a hardness tester and transversal microradiography, among negative control (fluoride free), positive control (sodium fluoride 1100 ppm, Crest Cavity Protection), and test dentifrice (3.0% bamboo salt with sodium fluoride 1,000 ppm) groups. RESULTS: Test and positive control groups significantly increased the level of the surface hardness and decreased mineral loss of the artificial caries-like enamel lesions compared to the negative control (P<0.05). The test dentifrice also significantly decreased the lesion depth compared to the other two groups (P<0.05).

Dental caries in 3-year-old children is associated more with child-rearing behaviors than mother-related health behaviors.

OBJECTIVE: We assessed whether child- or mother-related health behaviors were associated more strongly with dental caries in 3-year-old children. METHODS: Multiple logistic regression analyses were performed on dental caries' presence as the dependent variable with independent variables from the results of examination and a self-administered questionnaire of 396 mother-child pairs. RESULT: Dental caries of 3-year-old children was more strongly associated with child-related health behavior than mother-related health behavior. Of the child-related variables, "a habit of feeding in bed" [OR (odds ratio) 10.14; 95 percent class interval (CI) 1.80-56.97], "eating between meals three times a day or more" (OR 3.33; 95 percent CI 1.56-7.10), "consuming a sports drink three times a week or more" (OR 4.47; 95 percent CI 1.60-12.49), "having both home and professional preventive dental care" (OR 3.02; 95 percent CI 1.44-6.32), and "having professional preventive dental care" (OR 3.79; 95 percent CI 1.75-8.21) were significantly associated with dental caries in children. Of the mother-related variables, "brushing teeth once a day or less" (OR 2.72; 95 percent CI 1.19-6.20) and "drinking alcohol three times a week or more" (OR 0.38; 95 percent CI 0.16-0.93) had significant effects. CONCLUSION: Dental caries of 3-year-old children was more strongly associated with child-related health behavior than mother-related health behavior. The results of this study suggest that encouraging good child-rearing behavior among mothers could result in better dental health among their children regardless of the mother's dental health status.

Enamel fluoride uptake from mouthrinse solutions with different NaF concentrations.

OBJECTIVES: The influence on enamel fluoride uptake of reducing the NaF concentration of a mouthrinse solution by half, from 0.05-0.025%, was examined in elementary school children. METHODS: The participatory elementary school had employed school-based fluoride mouthrinse with 0.05% NaF solution since 1983, and in 1993, the NaF content was lowered to 0.025%. Dental examination and enamel biopsy of maxillary central incisors were performed just before the NaF content reduction for children who had received the daily 0.05% NaF mouthrinse for 2-5 years since 6 years of age. During 1993-95, dental examination and enamel biopsy were undertaken for newly enrolled 6-year-old children, and the same subjects were re-examined after 2 years. The same series of examinations were conducted for the control group, which consisted of children belonging to another elementary school without a fluoride program. RESULTS: The enamel fluoride concentration of 8-year-old children who used the 0.025% NaF mouthrinse for 2 years was 1810 +/- 535 ppm, reaching the same order as that in children who continued using the 0.05% NaF mouthrinse (1863 +/- 1358 ppm), and was significantly higher than that of children without fluoride programs (1113 +/- 303 ppm). There was no considerable increase of mean DMFT values due to the NaF content reduction. CONCLUSIONS: It was concluded that a daily 0.025% NaF mouthrinse provides the similar fluoride content for enamel as 0.05% NaF mouthrinse as long as the rinsing frequency is maintained.