Combined effect of fluoride varnish to Er:YAG or Nd:YAG laser on permeability of eroded root dentine.

OBJECTIVE: This study evaluated the combined effect of fluoride varnish to Er:YAG or Nd:YAG laser on permeability of eroded root dentine. DESIGN: Sixty slabs of bovine root dentine (2×2×2mm) were eroded with citric acid 0.3% (pH 3.2) during 2h and then kept in artificial saliva during 24h. Specimens were randomly assigned in 6 groups (n=10), to receive the following treatments: fluoride varnish; fluoride varnish+Er:YAG laser; fluoride varnish+Nd:YAG laser; non-fluoride varnish; non-fluoride varnish+Er:YAG laser; non-fluoride varnish+Nd:YAG laser. The Er:YAG (100mJ, 3Hz) and Nd:YAG (70mJ, 15Hz) were applied for 10s. Specimens were subjected to further erosive challenges with citric acid 0.3% 4×/day, during 1min, for 5 days, remaining in artificial saliva between cycles. Dentin permeability was then assessed. Two-way ANOVA demonstrated no significant interaction between laser and varnish (p=0.858). RESULTS: No effect was also detected for the main factor varnish (p=0.768), while permeability of eroded root dentin was significantly lower when such substrate was laser-irradiated, no matter the laser source (p<0.001). CONCLUSIONS: This study concluded that Er:YAG and Nd:YAG lasers can be employed to control the permeability of eroded root dentin, regardless of fluoride varnish application.

Is low birthweight associated with dental caries in permanent dentition?

The aim of this study was to test the hypothesis of association between low birthweight and dental caries. This study used data from the Third National Health and Nutritional Examination Survey, 1988-94 (NHANES III) including 7- to 11-year-old children with complete dental caries information (n = 2439). Two case definitions for dental caries were used: presence of the disease in more than one tooth, and more than 10% of teeth with dental caries. Low birthweight was defined as those children born weighing <2500 g. Other covariates used in the analysis were sex, age, poverty level, race/ethnicity, frequency of dental visit, education of head of household, daily sucrose intake, blood lead level and blood cotinine level. A separate analysis was conducted for each case definition of dental caries. Bivariable and stratified analysis was performed followed by multivariable Poisson regression. The Stata 8.0 statistical package was used to take into consideration the multistage complex sample. For the definition of more than one tooth with dental caries, the prevalence ratios (PRs) for bivariable and multivariable analyses were 1.28 [95% confidence interval (CI): 0.48, 3.42] and 1.01 [95% CI: 0.41, 2.49] respectively. For the definition of >10% of teeth with dental caries, the PRs for bivariable and multivariable analyses were 1.33 [95% CI: 0.60, 2.96] and 1.32 [95% CI: 0.75, 2.30] respectively. This study could not demonstrate an association between low birthweight and dental caries in permanent teeth of 7- to 11-year-old American children.