Pellicle Modification with Casein and Mucin Does Not Affect Surface Loss from Erosion and Abrasion.

AIM A combination of the proteins casein and mucin is known to modify the salivary pellicle and improve its protection of the underlying enamel from erosion. It is so far not known if this protection is confined solely to erosion, or if it also extends to abrasion, and this in vitro study aimed at investigating this question. METHODS A total of 72 human enamel specimens were prepared and randomly assigned to four groups: pellicle (P), casein/mucin (CM), pellicle + casein/mucin (PCM), and control (Ctrl). Each specimen underwent five cycles, each cycle consisting of a pellicle/treatment part, an erosion part (3 min in 1% citric acid, pH 3.6, 25°C, 70 rpm), and an abrasion part (50 toothbrush strokes within 25 s in toothpaste slurry with a 200-g load). The pellicle/treatment part consisted of 2 h of incubation in whole human saliva for group P, 2 h of incubation (25°C, 70 rpm) in a protein mixture of 1% casein and 0.27% mucin for group CM, and 2 h of incubation in saliva followed by 2 h of incubation in the protein mixture for group PCM. The fourth group (Ctrl) served as the control and was kept in a humid chamber without saliva or protein treatment. The enamel surfaces were scanned with an optical profilometer initially and after the final cycle, and surface loss was analyzed. Furthermore, the surface microhardness (SMH) was measured initially, after each pellicle/treatment part and each erosion cycle, and after the final abrasion cycle. The results were analyzed with Kruskal-Wallis and Wilcoxon tests with Bonferroni corrections. RESULTS The different treatments did not show differences in surface loss and therefore did not protect enamel from surface loss by abrasion. Nonetheless, we observed differences in the SMH values, namely the Ctrl group being significantly softer than the experimental groups. CONCLUSION The observed differences in SMH suggest that a different abrasion protocol could lead to differences in surface loss, and further investigation of whether and under which conditions pellicle modification leads to increased resistance to abrasion remains worthwhile

Susceptibility of enamel to initial erosion in relation to tooth type, tooth surface and enamel depth

This study aimed at assessing the susceptibility of different tooth types (molar/premolar), surfaces (buccal/lingual) and enamel depths (100, 200, 400 and 600 μm) to initial erosion measured by surface microhardness loss (ΔSMH) and calcium (Ca) release. Twenty molars and 20 premolars were divided into experimental and control groups, cut into lingual/ buccal halves, and ground/polished, removing 100 μm of enamel. The initial surface microhardness (SMH 0 ) was measured on all halves. The experimental group was subjected to 3 consecutive erosive challenges (30 ml/tooth of 1% citric acid, pH 3.6, 25 ° C, 1 min). After each challenge, ΔSMH and Ca release were measured. The same teeth were consecutively ground to 200, 400 and 600 μm depths, and the experimental group underwent 3 erosive challenges at each depth. No difference was found in SMH 0 between experimental and control groups. Multivariate nonparametric ANOVA showed no significant differences between lingual and buccal surfaces in ΔSMH (p = 0.801) or Ca release (p = 0.370). ΔSMH was significantly greater in premolars than in molars (p < 0.05), but not different with respect to enamel depth. Ca release decreased significantly with increasing depth. Regression between Ca release and ΔSMH at 100 μm depth showed lower slope and r 2 value, associated with greater Ca release values. At 200-600 μm depths, moderately large r 2 values were observed (0.651-0.830). In conclusion, different teeth and enamel depths have different susceptibility to erosion, so when Ca release is used to measure erosion, the depth of the test facet in enamel should be standardized, whereas this is less important if ΔSMH is used

Differences in susceptibility of deciduous and permanent teeth to erosion exist, albeit depending on protocol design and method of assessment.

Controversial results showing that deciduous teeth are more susceptible to erosion than permanent teeth might be related to study designs. We investigated how different conditions (pH: 3.0, 4.0, 5.0; acid agitation: gentle or vigorous; acid exposure times: 1-5 min) affect the susceptibility of both teeth to erosion. Enamel specimens (90 deciduous, 90 permanent) were distributed into groups (n = 15 permanent, n = 15 deciduous) according to acid pH (pH 5, 4 or 3) and agitation (gentle or vigorous) during erosive challenge. Both milder (less incubation time, gentle agitation, and higher pH) and more severe (longer incubation times, vigorous shaking, and lower pH) conditions were used. Demineralization was measured by relative surface microhardness (rSMH) and calcium released to the acid. Demineralization increased gradually for both teeth with increasing incubation time, agitation (gentle or vigorous), and with decreasing acid pH. The differences between deciduous and permanent teeth depended on the protocol design and assessment method. Under milder conditions, demineralization was better detectable with rSMH. Under more severe conditions, differences were more perceptible with calcium analyses. Differences exist in the susceptibility to erosion between deciduous and permanent teeth, but they are only distinguishable when the appropriate assessment method is used for the specific erosive condition

Synergistic effect between plant extracts and fluoride to protect against enamel erosion: An in vitro study.

Polyphenol-rich solutions, such as plant extracts and teas, can modify the salivary pellicle and improve the protection against dental erosion. In this study, we further explored how these polyphenol-rich plant extracts solutions behave in the presence of fluoride. We distributed enamel specimens into 9 groups (n = 15): Control_No_F- (Deionized water); Control_F- (500 ppm F-), Grape_Seed_No_F- (Grape seed extract), Grape_Seed_F- (Grape seed extract + 500 ppm F-), Grapefruit_Seed_No_F- (Grapefruit seed extract), Grapefruit_Seed_F- (Grapefruit seed extract + 500 ppm F-), Blueberry_No_F- (Blueberry extract), Blueberry_F- (Blueberry extract + 500 ppm F-), and Sn2+/F-_Rinse (commercial solution containing 800 ppm Sn2+ and 500 ppm F-). The specimens were submitted to 5 cycles (1 cycle per day), and each cycle consisted of: salivary pellicle formation (human saliva, 30 min, 37°C), modification of the pellicle (2 min, 25°C), pellicle formation (60 min, 37°C), and an erosive challenge (1 min, citric acid). Between cycles, the specimens were kept in a humid chamber. Relative surface hardness (rSH), relative surface reflection intensity (rSRI) and calcium released to the acid were analysed, using general linear models, and Kruskal-Wallis with post-hoc Dunn's tests. We observed that the presence of fluoride in synergy with the extract solutions provided better protection than the groups containing extract or fluoride only. For rSH, we observed a significant main effect of extracts (F(4,117) = 9.20; p<0.001) and fluoride (F(1,117) = 511.55; p<0.001), with a significant interaction (F(3,117) = 6.71; p<0.001). Grape_Seed_F- showed the best protection, better than fluoride, and Sn2+/F-_Rinse. Calcium results also showed greater protection for the groups containing fluoride, whereas for rSRI, despite a significant interaction between extract and fluoride (F(3,117) = 226.05; p<0.001), the differences between the groups were not as clearly observed. We conclude that polyphenols from plant extracts, when combined with fluoride, improve the protective effect of salivary pellicles against enamel erosion

Erosive effect of different dietary substances on deciduous and permanent teeth.

OBJECTIVES We investigated the effect of different dietary substances on deciduous and permanent enamel. MATERIALS AND METHODS Enamel specimens were prepared from human teeth (n = 108 deciduous molars and n = 108 permanent premolars). We measured the chemical parameters (pH, titratable acidity, viscosity, calcium, phosphate, fluoride concentration and degree of saturation) of nine dietary substances. The teeth were immersed in the respective substance (2 × 2 min; 30 °C; shaking), and we measured the baseline surface hardness (SH) in Vickers hardness numbers (VHN), and the changes in SH after 2 min (ΔSH2-0) and the 4 min (ΔSH4-0) immersion. We analysed the differences between deciduous and permanent teeth using the Wilcoxon test and correlated ΔSH to the different chemical parameters. RESULTS Deciduous teeth were significantly softer (549.53 ± 59.41 VHN) than permanent teeth (590.15 ± 55.31 VHN; p < 0.001) at baseline, but they were not more vulnerable to erosive demineralization. Only orange juice, which presented milder erosive potential, caused significantly more demineralisation in deciduous teeth at ΔSH4-0. Practically all chemical parameters significantly correlated with ΔSH (p < 0.05). Substances with lower pH, higher titratable acidity, lower Ca, higher Pi and lower F concentrations, higher viscosity and more undersaturated solutions presented more erosive demineralisation. CONCLUSION Different parameters in dietary substances affect erosive demineralisation in deciduous and permanent teeth, but we generally observed no differences in susceptibility to erosion between both types of teeth; only orange juice (less severe acid conditions) caused perceptible differences. CLINICAL RELEVANCE We observe that permanent teeth are harder than deciduous teeth, but most substances cause no perceptible difference in erosive demineralisation in both types of teeth

Rinsing solutions containing natural extracts and fluoride prevent enamel erosion in vitro

Polyphenols interact with salivary proteins and thus can improve the pellicle’s erosion protective properties. This effect could be exploited to create rinsing solutions with polyphenols as active ingredients for erosion prevention. Different from the current gold standard for erosion protective rinsing solutions, these rinses would not rely on stannous ions. This would offer alternatives for patients with concerns regarding the composition of rinsing solutions and preferring bio-products. Objective: To develop an erosion-preventive rinsing solution containing natural polyphenol-rich extracts. Methodology: Solutions were prepared with polyphenols from either grapeseed extract or cranberry extract, 500 ppm fluoride added, and additionally flavors and sweeteners. Controls were deionized water, 500 ppm fluoride solution, and the gold standard rinse in the field (Sn2+/F-). In total, 135 enamel specimens (n=15/group) were subjected to five cycles of salivary pellicle formation (30 min, 37°C), modification with the solutions (2 min, 25°C), further salivary pellicle formation (60 min, 37°C), and erosive challenge (1 min, 1% citric acid, pH 3.6). Relative surface microhardness (rSMH), surface reflection intensity (rSRI), and amount of calcium release (CaR) were investigated. Data were analyzed with Kruskal-Wallis and Wilcoxon rank sum tests (α=0.05). Results: The polyphenol solutions containing fluoride, as well as additional flavors, protected enamel better than fluoride alone, and similar to the Sn2+/F- solution, when investigating both rSMH and CaR. When measuring rSRI, Sn2+/F- showed the best protection, while the polyphenol solutions were similar to fluoride. Conclusion: For two of the three assessed parameters (rSMH and CaR), both developed polyphenol-rich rinsing solutions were able to protect enamel from erosion, improving/potentializing the effect of fluoride and matching the protection offered by the current gold standard rinsing solution

Rinsing solutions containing natural extracts and fluoride prevent enamel erosion in vitro.

BACKGROUND Polyphenols interact with salivary proteins and thus can improve the pellicle's erosion protective properties. This effect could be exploited to create rinsing solutions with polyphenols as active ingredients for erosion prevention. Different from the current gold standard for erosion protective rinsing solutions, these rinses would not rely on stannous ions. This would offer alternatives for patients with concerns regarding the composition of rinsing solutions and preferring bio-products. OBJECTIVE To develop an erosion-preventive rinsing solution containing natural polyphenol-rich extracts. METHODOLOGY Solutions were prepared with polyphenols from either grapeseed extract or cranberry extract, 500 ppm fluoride added, and additionally flavors and sweeteners. Controls were deionized water, 500 ppm fluoride solution, and the gold standard rinse in the field (Sn2+/F-). In total, 135 enamel specimens (n=15/group) were subjected to five cycles of salivary pellicle formation (30 min, 37°C), modification with the solutions (2 min, 25°C), further salivary pellicle formation (60 min, 37°C), and erosive challenge (1 min, 1% citric acid, pH 3.6). Relative surface microhardness (rSMH), surface reflection intensity (rSRI), and amount of calcium release (CaR) were investigated. Data were analyzed with Kruskal-Wallis and Wilcoxon rank sum tests (α=0.05). RESULTS The polyphenol solutions containing fluoride, as well as additional flavors, protected enamel better than fluoride alone, and similar to the Sn2+/F- solution, when investigating both rSMH and CaR. When measuring rSRI, Sn2+/F- showed the best protection, while the polyphenol solutions were similar to fluoride. CONCLUSION For two of the three assessed parameters (rSMH and CaR), both developed polyphenol-rich rinsing solutions were able to protect enamel from erosion, improving/potentializing the effect of fluoride and matching the protection offered by the current gold standard rinsing solution

Prevalence and severity of dental fluorosis among students from João Pessoa, PB, Brazil

The aim of this study was to determine the prevalence and severity of dental fluorosis among 12-15-year-old students from João Pessoa, PB, Brazil before starting a program of artificial fluoridation of drinking water. The use of fluoridated dentifrice was also surveyed. A sample of 1,402 students was randomly selected. However, 31 students refused to participate and 257 were not permanent residents in João Pessoa, thus leaving a final sample of 1,114 students. Clinical exams were carried out by two calibrated dentists (Kappa = 0.78) under natural indirect light. Upper and lower front teeth were cleaned with gauze and dried, and then examined using the TF index for fluorosis. A questionnaire on dentifrice ingestion and oral hygiene habits was applied to the students. The results revealed that fluorosis prevalence in this age group was higher than expected (29.2%). Most fluorosis cases were TF = 1 (66.8%), and the most severe cases were TF = 4 (2.2%). The majority of the students reported that they had been using fluoridated dentifrices since childhood; 95% of the participants preferred brands with a 1,500 ppm F concentration, and 40% remembered that they usually ingested or still ingest dentifrice during brushing. It was concluded that dental fluorosis prevalence among students in João Pessoa is higher than expected for an area with non-fluoridated water. However, although most students use fluoridated dentifrices, and almost half ingest slurry while brushing, the majority of cases had little aesthetic relevance from the professionals' point of view, thus suggesting that fluorosis is not a public health problem in the locality

Erosion protection conferred by whole human saliva, dialysed saliva, and artificial saliva.

During dental erosion, tooth minerals are dissolved, leading to a softening of the surface and consequently to irreversible surface loss. Components from human saliva form a pellicle on the tooth surface, providing some protection against erosion. To assess the effect of different components and compositions of saliva on the protective potential of the pellicle against enamel erosion, we prepared four different kinds of saliva: human whole stimulated saliva (HS), artificial saliva containing only ions (AS), human saliva dialysed against artificial saliva, containing salivary proteins and ions (HS/AS), and human saliva dialysed against deionised water, containing only salivary proteins but no ions (HS/DW). Enamel specimens underwent four cycles of immersion in either HS, AS, HS/AS, HS/DW, or a humid chamber (Ctrl), followed by erosion with citric acid. During the cycling process, the surface hardness and the calcium released from the surface of the specimens were measured. The different kinds of saliva provided different levels of protection, HS/DW exhibiting significantly better protection than all the other groups (p < 0.0001). Different components of saliva, therefore, have different effects on the protective properties of the pellicle and the right proportions of these components in saliva are critical for the ability to form a protective pellicle