Sports supplement induces dental structure corrosion: an in vitro pilot study / El suplemento deportivo induce corrosión en la estructura dental: un estudio piloto in vitro

Dietary supplements are being consumed with an increasingly high frequency among sports practitioners, whether at professional and/or amateur level. The supplements contain some nutritional properties in their composition, so they can dissolute the hydroxyapatite crystals of the enamel and favor the process of dental corrosion. The objective was to measure the corrosive power of protein-based supplementation (Whey Protein), under conditions that resemble the use of the supplement by the athletes, increasing the ecological validity of the study. The teeth of the test group (TG) were placed in contact with the Whey protein solution and then exposed to artificial saliva. And the teeth of the control group (CG) were exposed only to artificial saliva. The analysis occurred in natural healthy molar teeth, so that each tooth of the TG was immersed in 50 mL of supplement for 1.5 minutes and then placed in contact with the artificial saliva for 30 seconds. The same procedure was performed 5 times a day for 30, 60, 90, 120, 150 and 180 days. Each group, in its time (TG0 to TG180), underwent analysis of superficial roughness with the aid of optical profilometer (Talysurf CCI®, 3D model). The control group (CG) did not change its superficial roughness. Half of the teeth of the test group (TG) suffered loss of enamel surface. The values, in micrometers, of surface loss of the TG samples were 1.21; 2.1; 2.0; 1.04; 0.97; 0.8; 0.53; 1.14; 1.9; 2.0; 1.66; 1.80. The dietary supplement (Whey protein®) may be a potential cause of the dental corrosion process, considering the demineralization of hydroxyapatite that occurs along with the surface enamel loss.

Los suplementos dietéticos se consumen con una frecuencia cada vez más alta entre los practicantes de deportes, sea a nivel profesional y / o aficionado. Los suplementos contienen algunas propiedades nutricionales en su composición, por lo que pueden disolver los cristales de hidroxiapatita del esmalte y favorecer el proceso de corrosión dental. El objetivo fue medir el poder corrosivo de la suplementación a base de proteínas (proteína de suero), en condiciones que se asemejan al uso del suplemento por parte de los atletas, aumentando la validez ecológica del estudio. Los dientes del grupo de prueba (TG) se pusieron en contacto con la solución de proteína de suero y luego se expusieron a saliva artificial. Y los dientes del grupo de control (CG) estuvieron expuestos solo a saliva artificial. El análisis se realizó en dientes molares sanos naturales, cada diente del TG se sumergió en 50 ml de suplemento durante 1,5 minutos y luego se puso en contacto con la saliva artificial durante 30 segundos. El mismo procedimiento se realizó 5 veces al día durante 30, 60, 90, 120, 150 y 180 días. Cada grupo, en su momento (TG0 a TG180), se sometió a un análisis de rugosidad superficial con la ayuda de un perfilómetro óptico (Talysurf CCI®, modelo 3D). El grupo de control (CG) no cambió su rugosidad superficial. La mitad de los dientes del grupo de prueba (TG) sufrieron pérdida de la superficie del esmalte. Los valores, en micrómetros, de pérdida de superficie de las muestras de TG fueron 1.21; 2.1; 2,0; 1.04; 0,97; 0.8; 0,53; 1.14; 1.9; 2,0; 1,66; 1.80. El suplemento dietético (Whey protein®) puede ser una causa potencial del proceso de corrosión dental, considerando la desmineralización de la hidroxiapatita que ocurre junto con la pérdida de esmalte superficial.

Influence of cigarette smoke combined with different toothpastes on enamel erosion.

This in vitro study aimed to evaluate the effect of different toothpastes on dental enamel subjected to an erosive cycle with and without exposure to cigarette smoke. Bovine enamel specimens were randomly allocated into 12 groups (n = 12). For the in vitro simulation of smoking, half the groups underwent an exposure cycle of 20 cigarettes per day for 5 days. Subsequently, all groups were subjected to a 5-day erosion cycle intercalating demineralization (1 min; 1% citric acid; pH = 3.5) and treatment with toothpaste slurries (2 min) of NaF, SnF2, F/Sn/Chitosan, F/CaSiO3/Na3PO4, and F/bioactive glass. The control group was immersed in distilled water. Surface microhardness (SMH) was measured initially, after exposure to smoke, and after the erosive cycle, and %SMH was calculated. At the end of the experimental cycle, surface roughness, profilometry, and atomic force microscopy (AFM) were performed. SMH increased after exposure to cigarette smoke (p < 0.05). After the erosive cycle, there were no differences between the presence and absence of cigarette smoke exposure in SMH and roughness (p > 0.05). Besides increasing enamel SMH, cigarette smoke did not prevent enamel loss after the erosion cycle (p < 0.05). In profilometry, roughness and surface loss had the lowest values in the groups treated with SnF2 and F/Sn/Chitosan (p < 0.05). AFM showed lower mineral loss with F/CaSiO3/Na3PO4 and F/Sn/Chitosan. For all groups, except F/CaSiO3/Na3PO4, cigarette smoke resulted in higher enamel wear. F/Sn/Chitosan showed the best results against erosion.

Multiscale characterization of partially demineralized superficial and deep dentin surfaces.

The objective of this study was to address the following question: 'Which properties are modified in partially demineralized surfaces, compared with non-demineralized dentin surfaces, following orthophosphoric acid-etching as performed in clinical procedures?'. For this purpose, the complementary techniques atomic force microscopy/spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and contact angle measurements were used to provide a multiscale characterization of the dentin substrate undergoing the acidic preconditioning designed to enhance wetting. Special attention was given to the influence of the etching pretreatment on the nanomechanical properties at different levels of dentin surfaces, in both dry and hydrated conditions. The four-sided pyramid model (extended Hertz contact model) proved to be accurate for calculating the apparent Young's modulus, offering new information on the elasticity of dentin. The modulus value notably decreased following etching and surface hydration. This study underlines that after the acid etching pretreatment the contribution of the nanomechanical, morphological, and physicochemical modifications has a strong influence on the dentin adhesion properties and thus plays a significant role in the coupling of the adhesive-resin composite build-up material at the dentin surface.

Dentin decalcification during lithium treatment: case report.

Severe dental decay and changes in tooth structure have been reported in association with the use of lithium in Psychiatry, but lithium effects on tooth inorganic composition remain unknown. A 30-year-old woman with bipolar disorder, treated with lithium carbonate presented severe dental decay. Dentin samples from lithium and healthy volunteers were collected and submitted to ionic and ultrastructural analysis. Samples from the lithium patient exhibited irregular peritubular walls and the mineral crystals were irregularly arranged in the intertubular dentin. In addition, a decrease in Mg/P/Ca and an increase of Zn concentrations were detected. These data suggest that the severe dental decay and changes in the tooth structure observed for the lithium-treated patient are related to dentin mineral loss and that this pathological condition is different from caries lesions.

Exposure to lead exacerbates dental fluorosis.

AIM: Our aim was to test the hypothesis that co-exposure to lead and fluoride alter the severity of enamel fluorosis. MATERIALS AND METHODS: Wistar rats were allocated in four groups: control, and 3 groups that received water containing 100 ppm of fluoride (F), 30 ppm of lead (Pb), or 100 ppm of F and 30 ppm of Pb (F+Pb) from the beginning of gestation. Enamel analysis and F and Pb determinations in enamel, dentine, and bone were performed in 81-day-old animals. Fluorosis was quantified using a new fluorosis index based on the identification of incisor enamel defects (white bands and white islets, representing hypomineralization, and cavities) weighted according to their severity and quantity. Hypomineralization was validated histopathologically by polarizing microscopy and microradiography. Scores were given by two blinded calibrated examiners (intra and interexaminer kappa values were 0.8 and 0.86, respectively). RESULTS: The control and the Pb groups presented normal enamel. The F+Pb group presented more severe enamel defects compared with the F group (P<0.0001). CONCLUSIONS: This study shows that lead exacerbates dental fluorosis in rodents, suggesting that co-exposure to lead may affect the degree of fluorosis.

Mechanical and acid root treatment on periodontally affected human teeth: a scanning electronic microscopy

Aim: To evaluate the root topography of human teeth affected by periodontitis, after different root surface treatments. Methods: Forty-two periodontally affected single-rooted human teeth were selected and randomly divided into 7 groups (n=6): Cont- control group, which received no treatment; Sca- root surface scaling and root planning with curettes; ScaPh- Sca followed by 37%phosphoric acid gel etching for 15 s; ScaEdta- Sca followed by 24% EDTA gel pH 7 for 1 min; ScaCi- Sca followed by 30% citric acid pH 1.6 for 5 min; ScaTe- Sca followed by - mixture obtained by 500 mg tetracycline capsule dissolved in saline solution for 3 min; ScaTeg- Sca followed by 0.2 g/mL tetracycline gel pH 1.8 for 1 min. The specimens were analyzed by scanning electronic microscopy to verify the presence of calculus, demineralization level and residues of the product. Results: Calculus deposits were found in all control specimens. ScaEdta, ScaCi and ScaTeg removed completely calculus deposits and resulted in adequate demineralization without smear layer and smear plug on root surface. ScaTe produced great tetracycline residues with several demineralization areas on root dentin surface. Conclusions: ScaEdta, ScaCi and ScaTeg produced clean root surfaces associated with regular dentin demineralization.

Changes in surface morphology and mineralization level of human enamel following in-office bleaching with 35% hydrogen peroxide and light irradiation.

The objective of this study was to evaluate the alterations on surface morphology and mineral loss of human enamel following in-office bleaching with 35% hydrogen peroxide and light irradiation. Dental enamel samples were obtained from human third molars and randomly divided into 10 groups (n = 10). The control group remained untreated. Bleached groups were treated with one of three whitening products. Bleaching was performed in a single session, during which bleaching gel was applied to the enamel surface three times for 10 minutes each time. During treatment, the bleaching agents were either irradiated by a halogen light or an LED/diode laser or were not irradiated at all. Microhardness testing was performed with a Knoop indentor and the surface morphologic observations were carried out by scanning electron microscopy (SEM). Cross-sectional microhardness (CSMH) and polarized light microscopy (PLM) were used to measure the depth of demineralization. The results revealed a significant decrease in surface microhardness values and changes to the enamel morphology after bleaching. CSMH and PLM showed that bleached enamel presented lower volume percentage of mineral up to 40 micrometers from the enamel surface and demineralization areas located in the subsuperficial region of enamel, respectively. It was concluded that 35% hydrogen peroxide can alter the surface morphology and the mineralization level of the dental enamel surface and sub-surface regardless of what type of bleaching light is used.

Side effects of a non-peroxide-based home bleaching agent on dental enamel.

Changes in the chemistry and structure of enamel due to a non-peroxide-based home bleaching product (Rapid White) were studied in vitro using attenuated total reflectance-infrared spectroscopy, Raman spectroscopy, electron probe microanalysis, flame atomic absorption spectroscopy, and total reflection X-ray fluorescence. The results revealed that the citric-acid-containing gel-like component of the bleaching system substantially impacts on the dental hard tissue. Enamel is affected on several levels: (i) the organic component is removed from superficial and deeper enamel layers and remnants of the bleaching gel are embedded in the emptied voids; (ii) cracks and chemical inhomogeneities with respect to Ca and P occur on the surface; and (iii) within a submicron layer of enamel, the Ca-O bond strength in apatite decreases, thus enhancing calcium leakage from the bleached enamel hard tissue.

Analysis of the erosive potential of calcium-containing acidic beverages.

The occurrence and progress of enamel demineralization may be reduced in the presence of its reaction products, such as calcium. Therefore, in this study the hypothesis that lower erosive potential may be expected for calcium-containing beverages was tested. Ten commercially available beverages, five with and five without calcium supplementation, were tested in two phases. In the first phase, the pH, titratable acidity, and concentrations of calcium (total and ionic), phosphorus and fluoride, were analyzed. In the second phase, the ability of the test products to erode enamel was measured, at different time-points. Within the chemical properties tested, pH, calcium-ion concentration, and total calcium showed a strong correlation with enamel demineralization and enamel wear. Lower levels of enamel demineralization and wear were found for most of the calcium-containing beverages than for those without calcium. Calcium-ion content, as well as pH, were found to be good predictors of the erosive potential of the beverages tested. Generally, beverages supplemented with calcium had a reduced capacity to demineralize enamel.

Effect of lesion characteristics and mineralizing solution type on enamel remineralization in vitro.

The aim was to study the effect of lesion preparation technique and solution composition on remineralization of artificial lesions in vitro. Lesions were prepared with similar total mineral loss, but different mineral distribution, i.e., low (14.0) or high R (34.8) values. Lesions from both groups were remineralized (10 days, 37 degrees C) in two different solutions, with similar supersaturation with respect to hydroxyapatite (St), but calcium:phosphate ratios representing either hydroxyapatite stoichiometry or plaque fluid (PF). Remineralization was quantified microradiographically, mineral distribution was compared with natural white-spot lesions. Mineral loss and depth decreased significantly, and surface-zone mineral content (Zmax) increased significantly, in all lesions. Overall there was a significant relationship of decreasing remineralization with increasing Zmax, but not within either lesion type. PF was significantly more efficient than St in high-R lesions, with lesions remineralizing almost completely in PF. Remineralization was not significantly different in PF or St for low-R lesions but in high-R lesions, PF was more efficient than St, possibly through differences in relative saturations with respect to different calcium phosphates. Differences in area:solution ratios and baseline Zmax values may also have explained the different response to PF. Low-R lesions were similar to natural white-spot lesions in terms of mineral distribution, whereas high-R were not. Concluding, both lesion and remineralizing solution type had a marked influence on remineralization. It is proposed that use of low-R lesions would be more appropriate where more physiologically relevant mineral distribution is required, whereas high-R lesions would be appropriate for studying inherent remineralizing efficiency.

Ca, Pi, and F in the fluid of biofilm formed under sucrose.

Calcium (Ca), inorganic phosphorus (P(i)), and fluoride (F) concentrations are low in the whole plaque biofilm formed under exposure to sucrose. It was hypothesized that this would be reflected in the biofilm fluid, where these low values should greatly influence the de/remineralization process. Dental biofilms were formed in situ over enamel blocks mounted in palatal appliances and exposed 8 times/day to distilled water, glucose+fructose, or sucrose solutions for 14 days. While Ca, P(i), and F concentrations in the whole biofilms were significantly lower in the glucose+fructose and sucrose groups, no effect on biofilm fluid was observed, even after a cariogenic challenge. An increase in whole biofilm mineral ions was observed 24 hrs after the carbohydrate treatments were suspended, but this effect was also not observed in the fluid. These results suggest that there is a homeostatic mechanism that maintains biofilm fluid mineral ion concentration, regardless of its total concentration in the whole biofilm.

Effect of iron on bovine enamel and on the composition of the dental biofilm formed "in situ".

OBJECTIVES: This study investigated in situ the effect of iron (Fe) on the reduction of demineralization of bovine enamel, as well as on the composition of dental biofilm. DESIGN AND METHODS: Twelve volunteers were included in this blind crossover study, which was conducted in two stages of 14 days each. For each stage, the volunteers received palatal appliances containing four blocks of bovine enamel (4 mm x4 mm x 2.5 mm). Six volunteers dripped a solution of 15 mmol L(-1) ferrous sulphate onto the fragments and the remaining six dripped deionized water (eight times per day). After five minutes, a fresh 20% (w/v) sucrose solution was dripped onto all enamel blocks. During the experimental period the volunteers brushed their teeth with non-fluoridated dentifrice. After each stage, the percentage of surface microhardness change (%SMHC) and area of mineral loss (DeltaZ) were determined on enamel and the dental biofilm formed on the blocks was collected and analysed for F, P, Ca, Fe and alkali-soluble carbohydrates. The concentrations of F, Ca and Fe in enamel were also analysed after acid biopsies. RESULTS: There was a statistically significant increase in the P and Fe concentrations in the biofilms treated with ferrous sulphate (p<0.05), which was not observed for F, Ca and alkali-soluble carbohydrates. The group treated with ferrous sulphate had significantly lower %SMHC and DeltaZ when compared to control (p<0.05). CONCLUSIONS: These results showed that ferrous sulphate reduced the demineralization of enamel blocks and altered the ionic composition of the dental biofilm formed in situ.

Effect of mineral supplements to citric acid on enamel erosion.

The aim of this study was to evaluate the effect of mineral supplements to citric acid (1%; pH 2.21) on enamel erosion under controlled conditions in an artificial mouth. From each of 156 bovine incisors one polished enamel sample was prepared. The samples were divided among 13 experimental groups (n=12). In group 1 citric acid only was used (control). In groups 2-10 either calcium, phosphate or fluoride in various low concentrations was admixed to the citric acid. In groups 11-13 the citric acid was supplemented with a mixture of calcium, phosphate and fluoride. For demineralisation the specimens were rinsed with the respective solution for 1 min, immediately followed by a remineralisation period with artificial saliva (1 min). The specimens were cycled through this alternating procedure five times followed by rinsing for 8 h with artificial saliva. The de- and remineralisation cycle was repeated three times for each specimen interrupted by the 8 h-remineralisation periods. Before and after the experiments, the specimens were examined using microhardness testing (Knoop hardness) and laser profilometry. Hardness loss and enamel dissolution was significantly higher for the controls as compared to the remaining groups. Significantly lowest hardness loss for all groups was recorded for group 12 with admixture of calcium, phosphate and fluoride to citric acid. The significantly highest enamel loss was recorded for the controls compared to all other samples. Groups 3 and 4 revealed significantly lower and higher tissue loss compared to the remaining groups (2-13), respectively. The other groups did not differ significantly from each other. Modification of citric acid with calcium, phosphate and fluoride exerts a significant protective potential with respect to dental erosion. However, with the low concentrations applied enamel dissolution could not be completely prevented.

Effects of chelating agents and sodium hypochlorite on mineral content of root dentin.

Effects of combined and single use of EDTA, RC-Prep, and NaOCl on mineral content of root dentin were evaluated in vitro using energy dispersion spectrometric microanalysis. Thirty-six standardized midroot dentin specimens obtained from human anterior teeth were used. Specimens were polished and divided into six experimental groups. The first two groups were treated with EDTA or RC-Prep followed by NaOCl irrigation. Groups 3 to 5 were treated with EDTA, RC-Prep, and NaOCl, respectively. The last group was irrigated with saline solution as a control. Levels of calcium, phosphorus, and magnesium were measured in the root dentin after treatments. The results showed that (i) EDTA combined with NaOCl irrigation as final flush and NaOCl alone changed the calcium/phosphorus ratio of root dentin significantly (p < 0.05); and (ii) there was a significant increase in the magnesium level after the use of chelating agent combined with NaOCl (p < 0.05). It was concluded that using NaOCl irrigation as final flush altered the effectiveness of chelating agents on root dentin.

[An experimental study on demineralization of several beverages on bovine enamel].

OBJECTIVE: The aim of this study is to investigate the demineralization effects of several beverages on bovine enamel. METHODS: The concentration of calcium and phosphate in these beverages were measured by using EL 312e Micro-Plate after the bovine enamel was exposed to beverages for a period of 7 days. RESULTS: The data indicated that almost all of these beverages could cause demineralization of bovine enamel, except mineral water, and the concentration of calcium and phosphate in these beverages changed after the bovine enamel was exposed to beverages. There were great significant differences in demineralization abilities among different beverages (P < 0.01). The concentration of calcium and phosphate in beverages also changed with time (P < 0.01). CONCLUSION: All these beverages, except mineral water have erosive effects on bovine enamel. Demineralization degree varied with kinds of beverages. The fruit juice has the highest erosive effect on the enamel, and the calcium milk has the lowest erosive effect on the bovine enamel, when comparing with other beverages.

Effects of fluoride-supplemented sucrose on experimental dental caries and dental plaque pH.

Sucrose, 5% and 10% (w/v), supplemented with between 0 and 5 ppm fluoride (F), was tested for its influence in vitro on plaque-induced experimental in vitro enamel caries and plaque pH. Plaque growth on bovine enamel was initiated from saliva inocula and sustained in a multiple plaque growth system for up to 31 days by means of a basal medium with periodic applications of sucrose or sucrose supplemented with F. Change in enamel mineralization was assessed, before and after plaque growth, by microhardness testing and microradiography; pH was monitored with microelectrodes. It was found that enamel demineralization was inversely related to the F concentration in the range 2 to 5 ppm, for both 5% and 10% sucrose. Plaque pH responses were unaffected by the F supplements.

Air-rotor stripping and enamel demineralization in vitro.

This investigation sought to evaluate the effects of air-rotor stripping on the susceptibility of human enamel to demineralization using an in vitro caries model. Crowns of extracted premolar teeth were abraded (0.5 mm) on one proximal surface by air-rotor stripping. The teeth were placed in a demineralizing gel and removed at various intervals up to 336 hours. Lesion depth and mineral content on the abraded and intact surfaces was measured with contact microradiography and computerized image analysis (double window technique). For each time interval measured, lesion depth was greater (p < 0.05) on the abraded surfaces and mineral density was significantly less (p < 0.05). In a second experiment, the effect of fluoride supplements (dentifrice or topical gel) were examined on abraded and intact enamel surfaces that were exposed to the acid gel for 192 hours. The data showed that fluoride treatments significantly reduced lesion penetration on intact and abraded surfaces compared with a no fluoride group. Lesion depth on the abraded, fluoride treated surfaces was significantly greater (p < 0.05) than on the intact untreated surfaces. No significant differences (p < 0.05) were apparent between the fluoride treatment groups with respect to lesion depth and mineral density within the lesion. These results suggest that air-rotor stripping significantly increases the susceptibility of proximal enamel surfaces to demineralization. As a result, the clinician should use caution in the application of this technique until the long-term effects on caries susceptibility have been determined.