Evaluation of acid diffusion and fluoride selective electrode to measure the total fluoride in toothpastes / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the reliability of a method of measuring the total fluoride in fluoride-containing toothpastes with acid diffusion and fluoride selective electrode.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>The amount of total fluoride in the calcium containing toothpaste can be detected simply and accurately measured by acid diffusion and fluoride selective electrode.</p>

Prevention of enamel demineralization adjacent to orthodontic brackets bonded with resin-modified glass ionomer: an in vitro pH cycling study / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the resin-modified glass ionomer cement for inhibition of enamel demineralization adjacent to orthodontic brackets under a pH cycling experiment.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>It was suggested that resin-modified glass ionomer may become an orthodontic bonding agent to minimize enamel demineralization.</p>