Dual protective effect of the association of plant extracts and fluoride against dentine erosion: In the presence and absence of salivary pellicle.

OBJECTIVES: To verify the protective effect of plant extracts associated with fluoride against dental erosion of dentine, in the presence and absence of a salivary pellicle. METHODS: Dentine specimens (n = 270) were randomly distributed into 9 experimental groups (n = 30/group): GT (green tea extract); BE (blueberry extract); GSE (grape seed extract); NaF (sodium fluoride); GT+NaF (green tea extract and NaF); BE+NaF (blueberry extract and NaF); GSE+NaF (grape seed extract and NaF); negative control (deionized water); and a positive control (commercialized mouthrinse containing stannous and fluoride). Each group was further divided into two subgroups (n = 15), according to the presence (P) or absence (NP) of salivary pellicle. The specimens were submitted to 10 cycles: 30 min incubation in human saliva (P) or only in humid chamber (NP), 2 min immersion in experimental solutions, 60 min of incubation in saliva (P) or not (NP), and 1 min erosive challenge. Dentine surface loss (dSL-10 and dSL-total), amount of degraded collagen (dColl) and total calcium release (CaR) were evaluated. Data were analyzed with Kruskal-Wallis, Dunn's and Mann-Whitney U tests (p>0.05). RESULTS: Overall, the negative control presented the highest values of dSL, dColl and CaR, and the plant extracts showed different degrees of dentine protection. For the subgroup NP, GSE showed the best protection of the extracts, and the presence of fluoride generally further improved the protection for all extracts. For the subgroup P, only BE provided protection, while the presence of fluoride had no impact on dSL and dColl, but lowered CaR. The protection of the positive control was more evident on CaR than on dColl. CONCLUSION: We can conclude that the plant extracts showed a protective effect against dentine erosion, regardless of the presence of salivary pellicle, and that the fluoride seems to improve their protection.

Chapter 9: Acidic Beverages and Foods Associated with Dental Erosion and Erosive Tooth Wear.

Dental erosion is the partial demineralisation of the tooth surface caused by repeated exposure to acids. The loss of surface tissue, which results from simultaneous and/or subsequent exposure to mechanical forces is known as erosive tooth wear (ETW). Excessive consumption of acidic beverages and foods has been the main focus of research into erosion. Enamel dissolution is significantly associated with chemical parameters: pH, buffer capacity, titratable acidity, viscosity, as well as calcium, phosphate and fluoride concentrations in the beverages and foods. Some of these parameters are used to calculate the degree of saturation of a given substance, which represents its driving force to demineralise dental hard tissues. Undersaturated substances with low pH and high titratable acidity and high buffer capacity have greater erosive potential, while substances with high concentrations of Ca2+ and phosphate cause less demineralisation. Other physical parameters also modulate the demineralisation processes. Swishing drinks in the mouth tends to cause more erosion, since the Nernst layer is continuously renewed and does not reach saturation. Recent systematic reviews confirm that frequent consumption of carbonated/soft drinks are the main dietary factor associated with ETW. Vitamin C and frequent consumption of natural fruit juices and acidic snacks or sweets are also significantly associated with more ETW; whereas higher consumption of milk and yoghurt is a protecting factor. Patients presenting with ETW should have their dietary habits assessed by recording their complete dietary intake in a diet record sheet. Dentists should assess the erosive potential of the different beverages and foods, as well as the frequency of ingestion, then elaborate specific preventive measures and dietary interventions individually tailored to each patient.

Influence of desensitizing and anti-erosive toothpastes on dentine permeability: An in vitro study.

OBJECTIVE: This study analyzed the effect of desensitizing and/or anti-erosive toothpastes on dentine permeability. METHODS: One-mm dentin discs were prepared from human molars and exposed to EDTA solution (5 min, 17%). Initial dentine permeability was measured, under constant pressure. Specimens were randomly allocated into 10 groups: four anti-erosive toothpastes (calcium silicate + sodium phosphate, potassium nitrate, stannous chloride + chitosan, oligopeptide-104); four desensitizing toothpastes (arginine + calcium carbonate, calcium sodium phosphosilicate, strontium acetate, stannous fluoride); and two controls (regular fluoridated toothpaste, and human saliva). They were submitted to a 5-day erosion-abrasion cycling model. Erosion consisted of immersion in citric acid (2 min, 0.3%, natural pH ˜ 2.6, 4x/day), followed by 1 h exposure to human saliva. Specimens were brushed for 15 s (2 N, 45 strokes) with the toothpaste slurries (total exposure time of 2 min). After 5 cycles, the final dentine permeability was determined. Dentine permeability change was calculated as a percentage of the initial hydraulic conductance (%Lp). Data were analyzed with one-way ANOVA and Tukey tests (α=0.05). RESULTS: The toothpastes calcium silicate + sodium phosphate and potassium nitrate, showed significant decrease in %Lp, with no difference between them. The regular fluoridated toothpaste also decreased the %Lp, not differing from potassium nitrate. No desensitizing toothpaste showed change in %Lp. Human saliva, oligopeptide-104 and stannous chloride + chitosan presented significant increase in %Lp, without difference between them. CONCLUSION: Calcium silicate + sodium phosphate, potassium nitrate, and the regular fluoridated toothpaste decreased dentine permeability, whereas the desensitizing toothpastes tested did not. CLINICAL RELEVANCE: Toothpastes had distinct impacts on dentine permeability, which may reflect a variable effect on the treatment of dentine hypersensitivity. Within the limitations of a laboratory-based study, toothpastes with an anti-erosive claim could also be effective in reducing the pain in dentine hypersensitivity.