Melbourne Dental School - Research Publications
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ItemImportance of bioavailable calcium in fluoride dentifrices for enamel remineralization(ELSEVIER SCI LTD, 2018-11)OBJECTIVES: To compare remineralization of enamel subsurface lesions by fluoride dentifrices with added calcium in a double-blind, randomized, cross-over, in situ study. METHODS: Human enamel with subsurface lesions were prepared and inserted into intra-oral appliances worn by volunteers. A slurry (1 g toothpaste/4 ml H2O) was rinsed for 60 s, 4 times per day for 14 days. Seven toothpastes were tested: (i) 1450 ppm F (NaF), (ii) 5000 ppm F (NaF), (iii) 1450 ppm F (MFP) with calcium sodium phosphosilicate (CSP), (iv) 1450 ppm F (MFP) with CaCO3/Arg, (v) 1150 ppm F (SnF2) with amorphous calcium phosphate (ACP), (vi) 1100 ppm F (NaF) with casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and (vii) 5000 ppm F (NaF) with functionalized tri-calcium phosphate (TCP). Total (acid soluble) and bioavailable (water soluble) calcium, inorganic phosphate and fluoride levels of the dentifrices were measured using ion chromatography (F/MFP) and spectrophotometry (Ca and inorganic phosphate). Enamel lesion mineral content was measured using transverse microradiography. Data were statistically analysed using a linear mixed model. RESULTS: All calcium and fluoride containing toothpastes released > 90% of bioavailable fluoride and were superior to the respective fluoride alone toothpastes in remineralization of enamel subsurface lesions. The level of remineralization followed the order: CPP-ACP/1l00 ppm F > ACP/1150 ppm F = TCP/5000 ppm F > 5000 ppm F = CaCO3/Arg/1450 ppm F = CSP/1450 ppm F > 1450 ppm F. Bioavailable calcium levels significantly correlated with enhanced remineralization of enamel subsurface lesions. CONCLUSIONS: Bioavailable calcium in fluoride dentifrices enhanced remineralization of enamel subsurface lesions.
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ItemFood acid content and erosive potential of sugar-free confections(WILEY, 2017-06)BACKGROUND: Dental erosion is an increasingly prevalent problem associated with frequent consumption of acidic foods and beverages. The aim of this study was to measure the food acid content and the erosive potential of a variety of sugar-free confections. METHODS: Thirty sugar-free confections were selected and extracts analysed to determine pH, titratable acidity, chemical composition and apparent degree of saturation with respect to apatite. The effect of the sugar-free confections in artificial saliva on human enamel was determined in an in vitro dental erosion assay using change in surface microhardness. RESULTS: The change in surface microhardness was used to categorize the confections as high, moderate or low erosive potential. Seventeen of the 30 sugar-free confections were found to contain high concentrations of food acids, exhibit low pH and high titratable acidity and have high erosive potential. Significant correlations were found between the dental erosive potential (change in enamel surface microhardness) and pH and titratable acidity of the confections. Ten of these high erosive potential confections displayed dental messages on the packaging suggesting they were safe for teeth. CONCLUSIONS: Many sugar-free confections, even some with 'Toothfriendly' messages on the product label, contain high contents of food acids and have erosive potential.
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ItemPolyols and remineralisation of enamel subsurface lesions(ELSEVIER SCI LTD, 2017-11)UNLABELLED: Sugar-free chewing gum containing polyols has been demonstrated to reduce caries experience in randomised controlled clinical trials. A range of polyols (mannitol, sorbitol, xylitol and maltitol) can be found in sugar-free gums and it has been claimed that they can facilitate calcium uptake into enamel subsurface lesions promoting remineralisation. OBJECTIVES: The aim of this study was to compare the effect of polyols on remineralisation of enamel subsurface lesions in vitro by artificial saliva (AS) and by AS containing the salivary biomimetic casein phosphopeptide amorphous calcium phosphate (CPP-ACP). METHODS: The polyols (12.6% w/v) and CPP-ACP (0.376% w/v) were used at physiologically relevant concentrations approximating those released into saliva during chewing a CPP-ACP/polyol chewing gum. Enamel subsurface lesions were exposed to one of the polyols (xylitol, sorbitol, maltitol, mannitol) in AS or AS containing CPP-ACP for 7days at 37°C with a change of solution each day. Remineralisation of the enamel subsurface lesions was measured by transverse microradiography. RESULTS: A statistical test for equivalence showed there was no difference in remineralisation between the AS solutions with or without any of the polyols. The AS+CPP-ACP solution substantially promoted remineralisation over AS alone independently of any polyol added. CONCLUSION: This controlled in vitro study showed that polyols at physiologically relevant concentrations did not promote remineralisation of enamel subsurface lesions by facilitating calcium uptake into the lesion.
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ItemEffect of calcium phosphate addition to fluoride containing dental varnishes on enamel demineralization(WILEY, 2016-09)BACKGROUND: The aim of this study was to evaluate the ability of calcium phosphate and fluoride containing varnishes to inhibit enamel demineralization. METHODS: Six varnishes were selected for analysis: (1) Enamel Pro containing amorphous calcium phosphate; (2) Clinpro White containing functionalized tricalcium phosphate (fTCP); (3) MI Varnish containing casein phosphopeptide-stabilized amorphous calcium phosphate (CPP-ACP); (4) Duraphat (first no added calcium control); (5) Profluorid (second no added calcium control); and (6) placebo (no added calcium or fluoride control). Human enamel slabs (36) were each cut into half-slabs and covered with one of the six dental varnishes to create a window. The half-slabs were then individually immersed in a polyacrylate demineralization buffer pH 4.8 for four days at 37 °C with a change of solution each day. Mineral content was determined using transverse microradiography. RESULTS: All fluoride-containing varnishes significantly inhibited enamel demineralization when compared with the placebo varnish. However, out of the calcium phosphate and fluoride containing varnishes only MI Varnish, containing fluoride and CPP-ACP was superior to the fluoride-alone varnishes. MI Varnish also released the highest levels of calcium, phosphate and fluoride ions. CONCLUSIONS: MI Varnish containing fluoride and CPP-ACP was superior to the other varnishes in protecting against enamel demineralization.
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ItemThe potential acidogenicity of liquid breakfasts(ELSEVIER SCI LTD, 2016-06)OBJECTIVES: To determine the potential acidogenicy of liquid breakfasts. METHODS: In vitro acid production by Streptococcus mutans was measured in the beverages at a pH of 5.5, as was the fall in pH over 10min. The buffering capacity was determined, as well as the calcium, inorganic phosphate and fluoride concentrations (total and soluble) of the beverages. Bovine milk (UHT) was used for comparison. RESULTS: The rate of acid production by S. mutans, and pH fall over 10min was greater in liquid breakfasts compared to bovine milk. All beverages except one demonstrated a significantly lower buffering capacity than bovine milk. All beverages contained significantly greater concentrations of soluble calcium than bovine milk, and all except two contained significantly more soluble inorganic phosphate. CONCLUSIONS: S. mutans was able to generate significantly more acid in the liquid breakfasts than in bovine milk, indicating these drinks may contribute to a cariogenic diet. In general, the liquid breakfasts required significantly less acid than bovine milk to reduce their pH to the approximate critical pH for enamel demineralisation. However, the liquid breakfasts also tended to contain significantly more soluble calcium and inorganic phosphate than bovine milk. CLINICAL SIGNIFICANCE: The substantial amounts and various types of sugars found within liquid breakfast beverages may result in a significant pH drop in dental plaque following consumption of these products.