Combination of high-fluoride toothpaste and no post-brushing water rinsing on enamel demineralization using an in-situ caries model with orthodontic bands.

OBJECTIVE: To compare the effects on enamel demineralization and fluoride (F) retention of two different brushing­rinsing regimens. MATERIAL AND METHODS: An in-situ caries model with orthodontic bands was used for 8­9 weeks. A total of 20 orthodontic patients participated. They were randomized into two groups: (1) a test group using 5000 ppm F (n = 10) with no post-brushing water rinsing; and (2) a control group using 1450 ppm F (n = 10) with three sessions of post-brushing water rinsing. Orthodontic stainless-steel bands were applied to the two upper first premolars, leaving 2­3 mm of space away from the exposed buccal surface in order to accumulate plaque and provoke initial caries development. The teeth were extracted after 8 and 9 weeks, then analysed using quantitative light-induced fluorescence (QLF). Additionally, oral F retention was compared for the two groups. RESULTS: In comparison to the control group, the test regimen resulted in a non-significant smaller QLF lesion area and a significantly lower average QLF loss of fluorescence (P < 0.05). The highest F retention concentration under the band was found in the test group (P < 0.001). CONCLUSIONS: The combination of using a 5000 ppm F toothpaste and no post-brushing water rinsing had a greater anti-caries potential and resulted in elevated oral F retention compared to a 1450 ppm F toothpaste with three sessions of post-brushing water rinsing.

Altered inorganic composition of dental enamel and dentin in primary teeth from girls with Turner syndrome.

In Turner syndrome (TS) one X-chromosome is missing or defective. The amelogenin gene, located on the X-chromosome, plays a key role during the formation of dental enamel. The aim of this study was to find support for the hypothesis that impaired expression of the X-chromosome influences mineral incorporation during amelogenesis and, indirectly, during dentinogenesis. Primary tooth enamel and dentin from girls with TS were analysed and compared with the enamel and dentin of primary teeth from healthy girls. Qualitative and quantitative changes in the composition of TS enamel were found, in addition to morphological differences. Higher frequencies of subsurface lesions and rod-free zones were seen in TS enamel using polarized light microscopy. Similarly, scanning electron microscopy showed that the enamel rods from TS teeth were of atypical sizes and directions. Using X-ray microanalysis, high levels of calcium and phosphorus, and low levels of carbon, were found in both TS enamel and dentin. Using microradiography, a lower degree of mineralization was found in TS enamel. Rule induction analysis was performed to identify characteristic element patterns for TS. Low values of carbon were the most critical attributes for the outcome TS. The conclusion was that impaired expression of the X-chromosome has an impact on dental hard tissue formation.