Melbourne Dental School - Research Publications

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    The prebiotic effect of CPP-ACP sugar-free chewing gum
    Fernando, JR ; Butler, CA ; Adams, GG ; Mitchell, HL ; Dashper, SG ; Escobar, K ; Hoffmann, B ; Shen, P ; Walker, GD ; Yuan, Y ; Reynolds, C ; Reynolds, EC (ELSEVIER SCI LTD, 2019-12)
    OBJECTIVES: To determine if chewing gum containing casein phosphopeptide stabilised amorphous calcium phosphate (CPP-ACP) promoted an increase in the abundance of Streptococcus sanguinis and other species associated with dental health in supragingival plaque in a clinical study. MATERIALS AND METHODS: Nineteen participants were recruited for a three-leg cross-over, randomised, controlled clinical trial. Participants chewed a sugar-free gum with or without CPP-ACP six times daily for 20 min over two weeks. The study also involved no gum chewing (no gum) for the same two week period. Participants were randomly assigned to one of the test gums or no gum for each intervention period. Participants abstained from oral hygiene and had washout periods of two weeks between intervention periods. After each intervention period, supragingival plaque was collected and analysed for bacterial composition by sequencing the V4 variable region of the 16S rRNA gene. Data were analysed using a linear mixed model. RESULTS: The CPP-ACP gum intervention produced a significant (p < 0.01) increase in the proportions of S. sanguinis (112%), as well as the commensal species Rothia dentocariosa (127%), Corynebacterium durum (80%) and Streptococcus mitis (55%) when compared with the no gum intervention. All the species that were promoted by the CPP-ACP gum are known to possess one or both of the alkali-producing enzymes arginine deiminase and nitrate reductase. CONCLUSION: This clinical study demonstrated that chewing a sugar-free gum containing CPP-ACP promoted prebiosis by significantly increasing the proportion of S. sanguinis and other health-associated bacterial species in supragingival plaque. CLINICAL SIGNIFICANCE: Regular chewing of CPP-ACP sugar-free gum increases the proportions of health-associated commensal species in supragingival plaque to promote prebiosis and oral homeostasis.
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    The potential acidogenicity of liquid breakfasts
    Byrne, SJ ; Tan, KH ; Dashper, SG ; Shen, P ; Stanton, DP ; Yuan, Y ; Reynolds, EC (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.