Consumption of baked nuts or seeds reduces dental plaque acidogenicity after sucrose challenge.

PURPOSE: To assess the acidogenic potential of eight different types of baked nuts or seeds eaten alone and after a sucrose challenge using in-dwelling electrode telemetry. METHODS: Six participants wearing a mandibular partial prosthesis incorporated with a miniature glass pH electrode were enrolled. The plaque pH was measured after 5 or 6 days of plaque accumulation. To establish a control, the subjects were instructed to rinse with sucrose, without any subsequent treatment, at the first visit. At each subsequent test visit, the subjects were asked to chew sugar free xylitol gum or consume 10 g of baked (180 degrees C, 5 minutes) peanuts, walnuts, pistachios, cashews, almonds, sunflower seeds, pumpkin seeds, or watermelon seeds alone and 10 minutes after a sucrose rinse. The minimum plaque pH value and area of plaque pH curve under 5.7 (AUC5.7) during and after nut/seed consumption or gum chewing alone, the plaque pH value at 10 minutes after the sucrose rinse, the time required for the pH to return to >5.7 and AUC5.7 after the sucrose rinse with or without nut/seed consumption or gum chewing were calculated from the telemetric curves. RESULTS: The sucrose rinse induced a rapid decrease in the plaque pH to 4.32 +/- 0.17 at 10 minutes; this value remained below 5.7 for the measurement period. The AUC5.7 values were 34.58 +/- 7.27 and 63.55 +/- 15.17 for 40 and 60 minutes after the sucrose challenge, respectively. With the exception of cashews and pumpkin seeds (minimum pH, 5.42 and 5.63 respectively), the nuts or seeds did not decrease the plaque pH to below 5.7 when consumed alone, with the AUC5.7 values during and after consumption (total 40 minutes) ranging from 0.24 to 2.5 (8.44 for cashews), which were significantly lower than those after the sucrose challenge. Furthermore, nut/seed consumption or gum chewing after the sucrose challenge significantly reversed the sucrose-induced decrease in the plaque pH, and the time required for the pH to return to >5.7 and the AUC5.7 values for 60 minutes after the sucrose challenge were much less than that of the sucrose challenge without subsequent interference.

Effect of chlorhexidine application in a self-etching adhesive on the immediate resin-dentin bond strength.

PURPOSE: To investigate whether the application of chlorhexidine in a two-step self-etching adhesive has an adverse effect on the immediate resin-dentin bond strength. MATERIALS AND METHODS: Different amounts of 20 wt% chlorhexidine digluconate were added directly to the Clearfil SE Bond primer to prepare mixtures of 4 different concentrations of chlorhexidine: 0.05 wt%, 0.1 wt%, 0.5 wt%, and 1.0 wt%. Sixteen extracted third molars were randomly divided into 4 groups. Each group corresponded to one of the 4 chlorhexidine concentrations. Each of the 16 teeth was sectioned into halves. One half was customarily bonded with Clearfil SE Bond without chlorhexidine, and the other half was bonded with Clearfil SE Bond containing different concentrations of chlorhexidine. Microtensile bond strengths were tested immediately after specimen preparation. The modes of fractures were examined under a stereomicroscope. RESULTS: No significant difference of immediate resin-dentin bond strength was observed between the control groups and any of the experimental groups containing chlorhexidine (p > 0.05). CONCLUSION: The addition of chlorhexidine to a two-step self-etching adhesive primer (Clearfil SE Bond primer) has no adverse effect on the immediate resin-dentin bond strength when the chlorhexidine concentration in the primer is lower than or equal to 1.0 wt%.

[Evaluation of acid diffusion and fluoride selective electrode to measure the total fluoride in toothpastes].

OBJECTIVE: To evaluate the reliability of a method of measuring the total fluoride in fluoride-containing toothpastes with acid diffusion and fluoride selective electrode. METHODS: Four brands of commercially available non-fluoride toothpastes and fluoride-containing toothpastes were sampled. Fluoride was extracted from the toothpastes in 2 mol/L HC10(4) at room temperature overnight and then subjected to the measurement with fluoride electrode. RESULTS: Fluoride recovery of the non-fluoride toothpastes containing calcium as abrasive by this method was 99.5%-100.5%, more than 94% of total fluoride was measured from the marketed fluoride toothpastes, and the variation coefficient of this method was less than 1.54%. While the abrasive was silicon, the fluoride recovery of the non-fluoride toothpastes was 83.4%, and 89.7% of total fluoride was measured from the marketed fluoride-containing toothpastes. CONCLUSION: The amount of total fluoride in the calcium containing toothpaste can be detected simply and accurately measured by acid diffusion and fluoride selective electrode.

[Prevention of enamel demineralization adjacent to orthodontic brackets bonded with resin-modified glass ionomer: an in vitro pH cycling study].

OBJECTIVE: To investigate the resin-modified glass ionomer cement for inhibition of enamel demineralization adjacent to orthodontic brackets under a pH cycling experiment. METHODS: The study used 5 pairs of extracted human premolars. The experiment teeth were bonded with resin-modified glass ionomer, the control teeth were bonded with composite resin. All samples were under the pH cycling experiment each day for 60 days. Demineralization lesions of enamel adjacent to orthodontic brackets were evaluated with polarized light microscopy. The depth and area of the lesion, and the distance between the edge of the adhesive on the enamel surface and the border of the lesion were measured. RESULTS: The depth and area of lesions of control were greater than those of experiment group were. Paired t test showed significant differences (p < 0.001). There was always a distance between the lesions border and the glass ionomer cement. In control group, all lesions were developed under the edge of composite resin. CONCLUSION: It was suggested that resin-modified glass ionomer may become an orthodontic bonding agent to minimize enamel demineralization.