No abstract

The objective of the study was to compare the amounts of fluoride released by two glass-ionomer cements, a resin-modified glass-ionomer cement, a compomer and a fluoride-containing composite into deionized water and artificial saliva. Disc samples of each of the materials were fabricated and placed in either water or artificial saliva. Fluoride analysis of the media was performed periodically over 64 days. The data were analysed to show the rate of fluoride release per cm2 per hour for each material. The results showed that the fluoride release rate for all the materials in both solutions decreased dramatically after 24 h. The release rate in artificial saliva was significantly less than in water (P < 0.001). The resin-modified glass-ionomer cement consistently displayed the highest fluoride release rate per hour into both media.

The objective of the study was to compare the potential for fluoride recharge of two glass-ionomer cements, a resin-modified glass-ionomer cement, a compomer and a fluoride-containing composite in artificial saliva. Disc samples of each of the materials were placed into artificial saliva. The fluoride content of the artificial saliva was determined at various intervals up to 57 days. The discs were subjected to a 2 min exposure of NaF (500 parts/106). This recharge procedure was repeated at 64 and 120 days. The fluoride release was measured before and after recharge. The fluoride release for all of the materials increased after each exposure to NaF; however, the amount for the composite was very low. The resin-modified glass-ionomer cement displayed the greatest potential for fluoride recharge at 57 and 64 days (P<0.05). By 120 days, the amount of fluoride released in the 24 h post-recharge interval had decreased in all the materials. All the materials showed a potential for fluoride recharge. This effect, however, was minimal in the fluoride-containing composite.

Intra-oral remineralisation of experimental caries-like lesions in human enamel, as determined by polarised light microscopy and quantitative microradiography, was promoted to a similar extent (% fall in ΔZ, 18.6 and 19.0) by chewing a sorbitol or sorbitol/xylitol (3:l)-sweetened gum for 20 min after each of three meals and two sugary snacks daily. The results suggest that reported differences in the properties of the two sweeteners do not affect their ability to enhance remineralisation due to salivary stimulation.

The use of fluorescein-enhanced quantitative light-induced fluorescence (QLF) in the detection of in vitro root caries demineralization and reminerlization was investigated. Fourteen previously extracted human premolar roots were selected and determined to be caries-free. Cementum was removed and nail varnish applied leaving an exposed window. Positive and negative controls were selected. During a demineralizing regimen, roots were removed at regular intervals (12, 48, 72 and 120 h) and immersed in sodium fluorescein (0AE2 mg L ) )1 ). Following gentle rinsing, each root was examined using QLF before being returned to the demineralizing solution. Following 120 h, each tooth was sectioned through the lesion and one-half retained for transverse micro radiography (TMR) analysis. The remaining half were subjected to a remineralizing regimen undergoing the same fluorescein and QLF examinations at 7, 28 and 36 days. Results showed that QLF effectively monitored demineralization/remineralization of root dentine as represented by fluorescein penetration. TMR analysis showed good correlations with QLF (DZ/ DQ) after demineralization (r = 0AE89) and remineralization (r = 0AE84). The technique could represent an in vivo method for root caries detection and classification.