RESEARCHdental caries reduced the enamel demineralisation caused by sucrose rinses. 3 More recently, a study of 179 children aged 7 to 9 years, showed that consumption of 5 g of cheese following breakfast for a period of 2 years was effective in reducing caries. 9 In one extensive dietary survey it was shown that children who were caries-free consumed significantly more cheese than children who were more caries-prone. 10 Cheese is a good gustatory stimulant of salivary flow: consumption of a lump of cheese following a sugary snack almost abolishes the usual fall in plaque pH which follows sugar consumption. 1,11,12 However, the gustatory effect of cheese on saliva flow only partially accounts for its cariostatic action because the caries-reducing property of cheese is effective in desalivated animals. 13 The calcium concentration of dental plaque is an important determinant of the balance between enamel de-and remineralisation because the rate of dissolution of the enamel hydroxyapatite is determined chiefly by the level of saturation with calcium and phosphate ions of the environment of the tooth. Increasing the calcium concentration of the environment of the tooth disfavours de-and favours remineralisation. The calcium, but not the phosphate concentration of dental plaque increase significantly following the consumption of uncooked cheese on its own. 1-3 These observations suggest that changes in the calcium concentration of plaque following cheese consumption are one measure of the effectiveness of the cheese in reducing enamel demineralisation. 14 Calcium would be expected to diffuse most readily into plaques with a low calcium concentration because the concentration gradient between saliva and plaque is greater than with plaques high in calcium. This possibility warrants investigation because individuals who are prone to caries tend to have low mean plaque calcium concentration 14 -so, if the calcium entering plaque from cheese is a factor affecting caries, cheese might be most effective on those most caries-prone.Evidence supports the theory that the release of calcium ions from cheese and the diffusion of these ions into plaque is a major cause of the protective effect of cheese, by preventing demineralisation or by promoting the remineralisation of enamel.The data reported on the cariostatic properties of cheese refer to the effect of uncooked cheese on its own, following a meal or snack. The aims of the present study were:• To investigate if cheese-containing cooked meals are effective in increasing plaque calcium concentration • To compare the relative effect on plaque calcium concentration of: cheese-containing cooked meals; cheese-free control meals; and cheese consumed alone • To compare any changes in plaque calcium concentration between Objective Eating cheese by itself increases plaque calcium concentration -which is probably one mechanism of the wellestablished action of cheese in reducing experimental caries. The objective of the present study was to determine whether consumption of cheese as p...

One aim of the present laboratory study was to determine whether a visual scoring system (ERK) developed for occlusal caries could be applied to approximal lesions. A new histological technique (autofluorescence, AF) recognises dentine that is soft and would be removed with an excavator during operative treatment. A second aim was to investigate the relationship between the visual scoring system (ERK) and AF of dentine both occlusally and approximally. The sample comprised 93 extracted teeth chosen to represent the range of visual scores on approximal and occlusal surfaces. After sectioning through the investigation site, the cut faces were examined in a stereomicroscope and the depth of demineralization was scored. Autofluorescence was viewed with a confocal laser scanning microscope. Results showed reasonable correlation between the visual scores and the stereomicroscope histological evaluations for occlusal surfaces and non-cavitated approximal surfaces. However, cavitated approximal surface lesions were less advanced histologically than cavitated occlusal carious lesions. The AF technique indicated that several lesions with intact surfaces would have had soft, excavatable dentine, whereas several with microcavities would not.

Representative strains of oral streptococci, lactobacilli and bifidobacteria were incubated overnight with lactulose or other carbohydrates and the final pH recorded. Most bacteria tested were able to metabolize lactulose with the exception of strains of Streptococcus salivarius, Lactobacillus acidophilus and Lact. fermentum. Streptococcus mutans produced most acid overnight but the initial rate of acid production from lactulose by uninduced cultures was very low. Plaque pH was monitored in 12 volunteers following rinsing the mouth with lactulose, sucrose or sorbitol or Lactulose BP. These studies in vivo showed both lactulose and Lactulose BP to exhibit low acidogenic potential. Thus, although plaque bacteria are capable of fermenting lactulose, the results suggest that lactulose is likely to pose a small acidogenic challenge to teeth under normal conditions of use.

©Operative Dentistry, 2008, 33-3, 305-311 Clinical RelevanceThe fracture resistance of resin-modified glass ionomer cements merits consideration of their use as core materials for root-filled premolars. S Ferrier • BS Sekhon • PA Brunton SUMMARYDespite the successful use of dental amalgam for coronal-radicular dowel and core build-up in endodontically-treated posterior teeth, newer materials offer many potential advantages over amalgam and have better patient acceptance. This study compared the fracture resistance of coronal-radicular restorations made from three different direct restorative materials. Sixty human premolars were selected, 45 of which were root treated and decoronated. Fifteen of these premolars were restored using amalgam, 15 with composite and 15 using resin-modified glass ionomer. The 15 unrestored teeth were used as a control group. All the teeth were mounted in acrylic within steel containers and subjected to compressive loading to failure on a universal testing machine. The force required to fracture each core specimen was recorded as well as the proportion of core lost due to failure. The results showed dental amalgam as having the highest fracture resistance (mean 1.93kN, sd 0.22) followed by resin-modified glass ionomer (mean 1.05kN, sd 0.20), sound tooth (mean 0.79kN, sd 0.20) and composite (mean 0.75kN, sd 0.11). The differences among all groups were significant. These results demonstrate that, although resin-modified glass ionomer is significantly weaker than amalgam, these restorations were stronger than unrestored teeth and failed at forces in excess of those encountered in normal mastication. Amalgam cores, along with resin-modified glass ionomer, tended to fail less catastrophically than the other materials and, given their strength, would remain the material of choice in situations where abnormally high forces are expected.

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