ABSTRACT
OBJECTIVES: The purpose of the work was to establish the level and source of salivary fluoride, whether it could interact with tooth mineral and whether it was able to effect calcium re-acquisition and remineralisation. METHODS: Fluoride in saliva and in solution was measured by electrode, calcium by complexometric titration and phosphate colourimetrically-to measure salivary fluoride, its uptake by mineral and the effects of such low levels on calcium and phosphate levels in solution in contact with suspensions of mineral hydroxyapatite. RESULTS: Fluoride levels in saliva were low but could interact with hydroxyapatite. Such levels caused apatite crystallite growth and preferential acquisition of calcium by calcium-deficient apatite. CONCLUSIONS: Salivary fluoride contents rose with increasing water fluoride levels. It was acquired by hydroxyapatite mineral. Topical fluoride was stored on oral tissues. Even these low fluoride contents could cause mineral crystallite growth with preferential calcium uptake. On a mineral area basis these effects were caused by quite low fluoride uptakes. These findings do not support reliance upon large fluoride uptakes by tooth enamel as evidence for commensurate caries reductions.
Subject(s)
Cariostatic Agents/pharmacokinetics , Dental Caries/metabolism , Durapatite/metabolism , Fluorides/pharmacokinetics , Saliva/chemistry , Calcium/metabolism , Crystallization , Dental Enamel/metabolism , Humans , Phosphates/metabolism , Tooth RemineralizationABSTRACT
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 (0.2 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 (DeltaZ/DeltaQ) after demineralization (r = 0.89) and remineralization (r = 0.84). The technique could represent an in vivo method for root caries detection and classification.
Subject(s)
Bicuspid , Dental Caries/diagnosis , Tooth Remineralization , Fluorescein , Humans , Image Processing, Computer-Assisted , Microscopy, FluorescenceABSTRACT
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.
Subject(s)
Cariostatic Agents/chemistry , Compomers , Dental Materials/chemistry , Fluorides/chemistry , Acrylic Resins/chemistry , Aluminum Silicates/chemistry , Analysis of Variance , Cariostatic Agents/analysis , Composite Resins/chemistry , Esthetics, Dental , Fluorides/analysis , Glass Ionomer Cements/chemistry , Maleates/chemistry , Materials Testing , Methacrylates/chemistry , Polyurethanes/chemistry , Resin Cements/chemistry , Saliva, Artificial/chemistry , Silicates/chemistry , Time Factors , Water/chemistryABSTRACT
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.
Subject(s)
Cariostatic Agents/chemistry , Compomers , Dental Materials/chemistry , Fluorides/chemistry , Acrylic Resins/chemistry , Aluminum Silicates/chemistry , Analysis of Variance , Composite Resins/chemistry , Glass Ionomer Cements/chemistry , Humans , Maleates/chemistry , Materials Testing , Methacrylates/chemistry , Polyurethanes/chemistry , Resin Cements/chemistry , Saliva, Artificial/chemistry , Silicates/chemistry , Sodium Fluoride/chemistry , Time FactorsABSTRACT
The acidogenic potential of a group of popular cereal-based foods and fruits and total carbohydrate content of salivary expectorants following their consumption were assessed using an indwelling electrode with telemetry and the anthrone method. Paired t tests indicated that sorbitol did not cause the plaque pH to fall as low as any of the test foods (p <0.05) but there was no significant difference between sucrose and the test foods. Only the fruits produced less acid than sucrose. The breakfast cereals tended to yield the highest levels of total carbohydrate in the salivary expectorants although a greater percentage of original carbohydrate was retained after rice and bread. These results suggest the important effect of carbohydrate retention on plaque pH response.
Subject(s)
Carbohydrates/analysis , Eating , Edible Grain , Fruit , Saliva/chemistry , Acids/metabolism , Adult , Aged , Anthracenes , Bread/analysis , Cariogenic Agents/analysis , Dental Plaque/physiopathology , Edible Grain/chemistry , Electrodes , Female , Fruit/chemistry , Humans , Hydrogen-Ion Concentration , Indicators and Reagents , Male , Middle Aged , Oryza/chemistry , Sorbitol/pharmacology , Spectrophotometry , Sucrose/pharmacology , Telemetry/instrumentationABSTRACT
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 delta Z, 18.6 and 19.0) by chewing a sorbitol or sorbitol/xylitol (3:1)-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.
