Iron supplementation reduces the erosive potential of a cola drink on enamel and dentin in situ

Iron has been suggested to reduce the erosive potential of cola drinks in vitro. Objective: The aim of this study was to evaluate in situ the effect of ferrous sulfate supplementation on the inhibition of the erosion caused by a cola drink. Material and Methods: Ten adult volunteers participated in a crossover protocol conducted in two phases of 5 days, separated by a washout period of 7 days. In each phase, they wore palatal devices containing two human enamel and two human dentin blocks. The volunteers immersed the devices for 5 min in 150 mL of cola drink (Coca-Cola (TM), pH 2.6), containing ferrous sulfate (10 mmol/L) or not (control), 4 times per day. The effect of ferrous sulfate on the inhibition of erosion was evaluated by profilometry (wear). Data were analyzed by paired t tests (p<0.05). Results: The mean wear (+/- se) was significantly reduced in the presence of ferrous sulfate, both for enamel (control: 5.8 +/- 1.0 mu m; ferrous sulfate: 2.8 +/- 0.6 mu m) and dentin (control: 4.8 +/- 0.8 mu m; ferrous sulfate: 1.7 +/- 0.7 mu m). Conclusions: The supplementation of cola drinks with ferrous sulfate can be a good alternative for the reduction of their erosive potential. Additional studies should be done to test if lower ferrous sulfate concentrations can also have a protective effect as well as the combination of ferrous sulfate with other ions.

In situ effect of sodium fluoride or titanium tetrafluoride varnish and solution on carious demineralization of enamel

This study evaluated the effect of titanium tetrafluoride (TiF4) formulations on enamel carious demineralization in situ. Thirteen subjects took part in this cross-over, split-mouth, double-blind study performed in three phases of 14 d each. In each subject, two sound and two predemineralized specimens of bovine enamel were worn intra-orally and plaque accumulation was allowed. One sound and one predemineralized specimen in each subject was treated once with sodium fluoride (NaF) varnish or solution (Treatment A); TiF4 varnish or solution (Treatment B); or placebo varnish or no treatment (Treatment C). The initially sound enamel specimens were exposed to severe cariogenic challenge (20% sucrose, eight times daily for 5 min each time), whereas the predemineralized specimens were not. Eleven subjects were able to finish all experimental phases. The enamel alterations were quantified by surface hardness and transversal microradiography. Demineralization of previously sound enamel was reduced by all test formulations except for the NaF solution, while both TiF4 formulations were as effective as NaF varnish. For the predemineralized specimens, enamel surface hardness was increased only by TiF4 formulations, while subsurface mineral remineralization could not be seen in any group. Within the experimental protocol, TiF4 was able to decrease enamel demineralization to a similar degree as NaF varnish under severe cariogenic challenges, while only TiF4 formulations remineralized the enamel surface.

Minimal alterations on the enamel surface by micro-abrasion: in vitro roughness and wear assessments

Objective: To evaluate the in vitro changes on the enamel surface after a micro-abrasion treatment promoted by different products. Material and Methods: Fifty (50) fragments of bovine enamel (15 mm × 5 mm) were randomly assigned to five groups (n=10) according to the product utilized: G1 (control)= silicone polisher (TDV), G2= 37% phosphoric acid (3M/ESPE) + pumice stone (SS White), G3= Micropol (DMC Equipment), G4= Opalustre (Ultradent) and G5= Whiteness RM (FGM Dental Products). Roughness and wear were the responsible variables used to analyze these surfaces in four stages: baseline, 60 s and 120 s after the micro-abrasion and after polishing, using a Hommel Tester T1000 device. After the tests, a normal distribution of data was verified, with repeated ANOVA analyses (p?0.05) which were used to compare each product in different stages. One-way ANOVA and Tukey tests were applied for individual comparisons between the products in each stage (p?0.05). Results: Means and standard deviations of roughness and wear (µm) after all the promoted stages were: G1=7.26(1.81)/13.16(2.67), G2=2.02(0.62)/37.44(3.33), G3=1.81(0.91)/34.93(6.92), G4=1.92(0.29)/38.42(0.65) and G5=1.98(0.53)/33.45(2.66). At 60 seconds, all products tended to produce less surface roughness with a variable gradual decrease over time. After polishing, there were no statistically significant differences between the groups, except for G1. Independent of the product utilized, the enamel wear occurred after the micro-abrasion. Conclusions: In this in vitro study, enamel micro-abrasion presented itself as a conservative approach, regardless of the type of the paste compound utilized. These products promoted minor roughness alterations and minimal wear. The use of phosphoric acid and pumice stone showed similar results to commercial products for the micro-abrasion with regard to the surface roughness and wear.

Effects of various forms of calcium added to chewing gum on initial enamel carious lesions in situ

The purpose of this randomized, cross-over in situ study was to determine the effects of 4 chewing gums on artificial caries-like subsurface lesions. Two chewing gums (1 with zinc citrate and 1 without) contained dicalcium phosphate (3.9%), calcium gluconate (1.8%) and calcium lactate (0.45%), 1 chewing gum contained casein phosphopeptide-amorphous calcium phosphate nanocomplexes (0.7%), and another one contained no calcium. Fifteen subjects without current caries activity (7 male, 8 female; mean age: 27.5 +/- 2.5 years) wore removable buccal appliances in the lower jaw with 4 bovine enamel slabs with subsurface lesions. The appliances were inserted immediately before gum chewing for 20 min and then retained for an additional 20 min. This was performed 4 times per day. Every subject chewed 4 different chewing gums over 4 periods of 14 days each. During a fifth period (control) the subjects only wore the appliances without chewing gum. At completion of each period the enamel slabs were embedded, sectioned and subjected to transversal microradiography. With regard to change of mineral loss and of lesion depth no significant differences could be found between chewing gums containing calcium and calcium-free chewing gums. Moreover, the chewing gum groups and the control group did not differ significantly if adjustments were made for baseline values (p > 0.05; ANCOVA). Under the conditions of the present study it may be concluded that the use of chewing gum offers no additional remineralizing benefit to buccal tooth surfaces, even if the chewing gum contains calcium compounds.

Action of food preservatives on 14-days dental biofilm formation, biofilm vitality and biofilm-derived enamel demineralisation in situ

AIMS The aims of this double-blind, controlled, crossover study were to assess the influence of food preservatives on in situ dental biofilm growth and vitality, and to evaluate their influence on the ability of dental biofilm to demineralize underlying enamel over a period of 14 days. MATERIALS AND METHODS Twenty volunteers wore appliances with six specimens each of bovine enamel to build up intra-oral biofilms. During four test cycles of 14 days, the subjects had to place the appliance in one of the assigned controls or active solutions twice a day for a minute: negative control 0.9 % saline, 0.1 % benzoate (BA), 0.1 % sorbate (SA) and 0.2 % chlorhexidine (CHX positive control). After 14 days, the biofilms on two of the slabs were stained to visualize vital and dead bacteria to assess biofilm thickness (BT) and bacterial vitality (BV). Further, slabs were taken to determine mineral loss (ML), by quantitative light-induced laser fluorescence (QLF) and transversal microradiography (TMR), moreover the lesion depths (LD). RESULTS Nineteen subjects completed all test cycles. Use of SA, BA and CHX resulted in a significantly reduced BV compared to NaCl (p < 0.001). Only CHX exerted a statistically significant retardation in BT as compared to saline. Differences between SA and BA were not significant (p > 0.05) for both parameters. TMR analysis revealed the highest LD values in the NaCl group (43.6 ± 44.2 μm) and the lowest with CHX (11.7 ± 39.4 μm), while SA (22.9 ± 45.2 μm) and BA (21.4 ± 38.5 μm) lay in between. Similarly for ML, the highest mean values of 128.1 ± 207.3 vol% μm were assessed for NaCl, the lowest for CHX (-16.8 ± 284.2 vol% μm), while SA and BA led to values of 83.2 ± 150.9 and 98.4 ± 191.2 vol% μm, respectively. With QLF for both controls, NaCl (-33.8 ± 101.3 mm(2) %) and CHX (-16.9 ± 69.9 mm(2) %), negative values were recorded reflecting a diminution of fluorescence, while positive values were found with SA (33.9 ± 158.2 mm(2) %) and BA (24.8 ± 118.0 mm(2) %) depicting a fluorescence gain. These differences were non-significant (p > 0.05). CONCLUSION The biofilm model permited the assessment of undisturbed oral biofilm formation influenced by antibacterial components under clinical conditions for a period of 14 days. An effect of BA and SA on the demineralization of enamel could be demonstrated by TMR and QLF, but these new findings have to be seen as a trend. As part of our daily diet, these preservatives exert an impact on the metabolism of the dental biofilm, and therefore may even influence demineralization processes of the underlying dental enamel in situ.

Fluoride varnishes with calcium glycerophosphate: fluoride release and effect on in vitro enamel demineralization

The aims of this study were (1) to assess the amount of fluoride (F) released from varnishes containing calcium glycerophosphate (CaGP) and (2) to assess the effect of the experimental varnishes on in vitro demineralization. Six test groups using 5 varnishes: base varnish (no active ingredients); Duraphat® (2.26% NaF); Duofluorid® (5.63% NaF/CaF2); experimental varnish 1 (1% CaGP/5.63% NaF/CaF2); experimental varnish 2 (5% CaGP/5.63% NaF/CaF2); and no varnish were set up. In stage 1, 60 acrylic blocks were randomly distributed into 6 groups (n = 10). Then 300 µg of each varnish was applied to each block. The blocks were immersed in deionized water, which was changed after 1, 8, 12, 24, 48 and 72 hours. Fluoride concentration in the water was analyzed using a fluoride electrode. In stage 2, 60 bovine enamel samples were distributed into 6 groups (n = 10), and treated with 300 µg of the respective varnish. After 6 h the varnish was removed and the samples were subjected to a 7-day in vitro pH cycle (6 h demineralization/18 h remineralization per day). The demineralization was measured using surface hardness. The results showed that both experimental varnishes released more fluoride than Duofluorid® and Duraphat® (p < 0.05), but Duraphat® showed the best preventive effect by decreasing enamel hardness loss (p < 0.05). Therefore, we conclude that even though (1) the experimental varnishes containing CaGP released greater amounts of F, (2) they did not increase in the preventive effect against enamel demineralization.

Different bacterial models for in vitro induction of non-cavitated enamel caries-like lesions: Microhardness and polarized light miscroscopy analyses

The aim of this study was to compare different bacterial models for in vitro induction of non-cavitated enamel caries-like lesions by microhardness and polarized light microscopy analyses. One hundred blocks of bovine enamel were randomly divided into four groups (n = 25) according to the bacterial model for caries induction: (A) Streptococcus mutans, (B) S. mutans and Lactobacillus acidophilus, (C) S. mutans and L. casei, and (D) S. mutans, L. acidophilus, and L. casei. Within each group, the blocks were randomly divided into five subgroups according to the duration of the period of caries induction (4-20 days). The enamel blocks were immersed in cariogenic solution containing the microorganisms, which was changed every 48 h. Groups C and D presented lower surface hardness values (SMH) and higher area of hardness loss (ΔS) after the cariogenic challenge than groups A and B (P < 0.05). As regards lesion depth, under polarized light microscopy, group A presented significantly lower values, and groups C and D the highest values. Group B showed a higher value than group A (P < 0.05). Groups A and B exhibited subsurface caries lesions after all treatment durations, while groups C and D presented erosion-type lesions with surface softening. The model using S. mutans, whether or not it was associated with L. acidophilus, was less aggressive and may be used for the induction of non-cavitated enamel caries-like lesions. The optimal period for inducing caries-like lesions was 8 days.

Avaliação in vitro do efeito remineralizante de diferentes princípios bioativos no esmalte dental bovino submetido à erosão

O objetivo deste estudo in vitro foi avaliar por meio da fluorescência de Raios X, oefeito remineralizante de dois diferentes princípios bioativos contidos no Desensibilize Nano P (nanopartículas de hidroxiapatita de cálcio) e no GC Tooth Mousse (CPP-ACP,fosfopeptídios de caseína e fosfato de cálcio amorfo) assim como da saliva artificial e do fluoreto de sódio gel neutro no esmalte dental bovino submetido a desafio erosivo. Foram utilizados 20 incisivos bovinos, seccionados na linha amelo-cementária, fixados em resina epóxi e padronizados pela planificação da superfície. Foram obtidos 20 corpos de prova (CP) que foram divididos aleatoriamente em 4 grupos. Todos os dentes foram avaliadosinicialmente para a obtenção da contagem dos elementos fósforo (P), cálcio (Ca) e estrôncio (Sr) interpretados a partir de um espectro de Fluorescência de Raios X obtidos pelo Artax 800. Após uma semana da medição inicial, cada grupo de amostras foi imerso em uma solução de 10 ml de ácido cítrico a 2% (pH 2,6) por 90 minutos. Imediatamente após obtenção dos espectros dos dentes submetidos ao desafio erosivo, cada grupo recebeu seus tratamentos correspondentes. Grupo 1 (Saliva) - saliva; Grupo 2 (Flúor) - Flúor; Grupo 3 (Nano P) - Desensibilize Nano P; Grupo 4 (Recaldent) - GC Tooth Mousse. A leitura e os tratamentos eram realizados a cada sete dias sendo repetidos por de 3 semanas. Foi utilizado inicialmente o teste de Bonferroni para comparação das médias de P, Ca e Sr dentro de cada grupo, com um nível de significância de 0,05 (p=0,05), que demonstrou remineralização efetiva na terceira semana de tratamento no grupo Nano P. Posteriormente foi utilizado o teste T-Student para comparação das médias de P, Ca e Sr entre os diferentes grupos, também com um nível de significância de 0,05 (p=0,05). O grupo Nano P foi mais efetivo do que todos os outros grupos e o grupo Saliva menos efetivo que Fluor e Recaldent após três semanas de tratamento. Nestas condições expirimentais in vitro a pasta Desensibilize Nano P foi eficaz noprocesso de remineralização dental desde a primeira semana de tratamento e estável após 3 semanas de tratamento do que os tratamentos com Saliva, Flúor e GC Tooth Mousse.

Avaliação do potencial remineralizante de pastas e soluções com compostos bioativos no esmalte dental bovino submetido a ciclos de desafio erosivo

O objetivo deste estudo foi avaliar in vitro por meio da Fluorescência de Raios X por Dispersão de Energia (XRF), Microdureza Vickers (MV) e Microscopia Eletrônica de Varredura (MEV) o efeito remineralizante de diferentes princípios bioativos, tais quais, nanopartículas de hidroxiapatita de cálcio (nanoHAp) associadas ou não a fluoreto, fosfopeptídeos de caseína do leite e fosfato de cálcio amorfo (CPP-ACP) associados ou não a fluoreto, fluoreto de sódio e saliva no esmalte dental bovino submetido a ciclagem des-remineralizante simulando lesão erosiva por alto desafio ácido. Foram obtidos 58 corpos de prova (CP) a partir de 58 incisivos bovinos que foram divididos aleatoriamente em 8 grupos, com 7 CP cada um e 2 CP para obtenção de imagem em MEV do esmalte hígido. Cada grupo foi denominado conforme os respectivos tratamentos a serem utilizados. Grupo 1 (G1) Controle; Grupo 2 (G2) Desensibilize Nano P experimental (nanopartículas de hidroxiapatita de cálcio); Grupo 3 (G3) Desensibilize Nano P (nanopartículas de hidroxiapatita de cálcio e flúor); Grupo4 (G4) GC Tooth Mousse (CPP-ACP, fosfopeptídios de caseína e fosfato de cálcio amorfo Recaldent ); Grupo 5 (G5) GC Tooth Mousse Plus (CPP-ACP, fosfopeptídios de caseína e fosfato de cálcio amorfo Recaldent + 900 ppm de flúor); Grupo 6 (G6) solução aquosa de fluoreto de sódio (0,05%); Grupo 7 (G7) solução aquosa de nanopartículas de hidroxiapatita de cálcio (0,375%) e Grupo 8 (G8) solução aquosa de nanopartículas de hidroxiapatita de cálcio (0,375%) + flúor (0,05%). Foram obtidos os valores de XRF e MV antes e depois do tratamento. Durante um período experimental de 10 dias, os CPs foram submetidos a um processo cíclico de des-remineralização incluindo vários ataques diários com ácido cítrico 0,05M (pH 2,3), 6 vezes de 2 minutos ao dia, bem como as aplicações das soluções teste e períodos de remineralização em saliva artificial. O tempo entre os ciclos era de 1,5 h. Foram obtidas imagens em MEV para análise da superfície após o tratamento. Através da análise estatística pelo teste t student (p = 0,05), foram encontrados os seguintes resultados: o grupo controle teve uma desmineralização considerada severa; houve aumento na contagem de P em todos os grupos que receberam tratamento, exceto o G1, igualando ou até mesmo aumentando no caso do G5, em relação a contagem inicial; houve aumento na contagem de Ca em todos os grupos que receberam tratamento, exceto no G1, igualando ou até mesmo aumentando no caso do G4, em relação a contagem inicial; houve perda de microdureza superficial em todos os grupos; o G7 teve comportamento similar ao G1 e o G3 teve comportamento inferior ao G5 em relação ao P. E todos os outros grupos tiveram comportamento superior ao controle; o G4 e o G5 tiveram um comportamento superior ao G2 em relação ao Ca. O G5 teve comportamento superior ao G3 também em relação ao Ca e todos os grupos foram superiores ao controle; o G7 teve comportamento similar ao controle em relação a microdureza superficial e todos os outros grupos foram superiores ao controle.

The effect of an experimental 4% TiF(4) varnish compared to NaF varnishes and 4% TiF(4) solution on dental erosion in vitro

This in vitro study assessed the effect of an experimental 4% TiF(4) varnish compared to commercial NaF and NaF/CaF(2) varnishes and 4% TiF(4) solution on enamel erosion. For this, 72 bovine enamel specimens were randomly allocated to the following treatments: NaF varnish (2.26% F), NaF/CaF(2) varnish (5.63% F), 4% TiF(4) varnish (2.45% F), F-free placebo varnish, 4% TiF(4) solution (2.45% F) and control (not treated). The varnishes were applied in a thin layer and removed after 6 h. The solution was applied to the enamel surface for 1 min. Then, the specimens were alternately de- and remineralized (6 times/day) in an artificial mouth for 5 days at 37 degrees C. Demineralization was performed with the beverage Sprite (1 min, 3 ml/min) and remineralization with artificial saliva (day: 59 min, 0.5 ml/min; during the night: 0.1 ml/min). The mean daily increment of erosion and the cumulative erosion data were tested using ANOVA and ANCOVA, respectively, followed by Tukey's test (alpha = 0.05). The mean daily erosion increments and cumulative erosion (micrometers) were significantly less for the TiF(4) varnish (0.30 +/- 0.11/0.65 +/- 0.75) than for the NaF varnish (0.58 +/- 0.11/1.47 +/- 1.07) or the NaF/CaF(2) varnish (0.62 +/- 0.10/1.68 +/- 1.17), which in turn showed significantly less erosion than the placebo varnish (0.78 +/- 0.12/2.05 +/- 1.43), TiF(4) solution (0.86 +/- 0.11/2.05 +/- 1.49) and control (0.77 +/- 0.16/2.06 +/- 1.49). In conclusion, the TiF(4) varnish seems to be a promising treatment to reduce enamel loss under mild erosive conditions. Copyright (C) 2008 S. Karger AG, Basel.

Short-term in situ/ex vivo study of the anticariogenic potential of a resin-modified glass-ionomer cement associated with adhesive systems

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Comparison of Methods for Evaluating Mineral Loss: Hardness versus Synchrotron Microcomputed Tomography

This study analyzed degrees of demineralization in bovine enamel using synchrotron microcomputed tomography (SMCT) and hardness measurements (Knoop hardness number, KHN). For 5 days, 40 bovine enamel blocks were individually subjected to a pH cycling model and treatment with fluoride dentifrices (placebo, 275, 550 and 1,100 mu g F/g) diluted in deionized water twice a day. Surface hardness number and cross-sectional profiles of hardness and mineral concentration (by SMCT) were determined. Integrated hardness (KHN x mu m) for sound and demineralized specimens was calculated and subtracted to give the integrated loss of hardness (Delta KHN) for the lesions. Increasing fluoride concentration in the dentifrices led to higher values for surface hardness after pH cycling and mineral concentration (g(HAp) cm(-3)), and lower values for Delta KHN (p < 0.05). From the present results, it may be concluded that hardness measurements revealed demineralization in all groups, which was lower in groups treated with dentifrice with a higher F concentration. SMCT and hardness measurements gave similar results in areas with higher demineralization, but diverged in areas with lower demineralization. Copyright (C) 2009 S. Karger AG, Basel

In vitro Evaluation of Dentifrice with Low Fluoride Content Supplemented with Trimetaphosphate

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Evaluation of Laser Fluorescence in the Monitoring of the Initial Stage of the De-/Remineralization Process: An in vitro and in situ Study

This study aimed to evaluate laser fluorescence (LF) for monitoring the initial stage of subsurface de- and remineralization (<150 mu m depth). Ninety-six sound blocks of bovine enamel, selected according to surface hardness (SH) and LF were used in two experimental studies, in vitro and in situ. In vitro, blocks were exposed to a demineralizing solution, then remineralized by pH cycling for 6 days. In situ, 10 volunteers wore acrylic palatal appliances, each containing 4 dental enamel blocks that were demineralized for 14 days by exposure to 20% sucrose solution. Following this treatment, blocks were submitted to remineralization for 1 week with fluoride dentifrice (1,100 mu g F/g). In both experiments, SH and LH were measured after demineralization and after remineralization. Further, enamel blocks were selected after the demineralization/remineralization steps for measurement of cross-sectional hardness and integrated loss of subsurface hardness (Delta KHN). SH and Delta KHN showed significant differences among the phases in each study. LF values for sound, demineralized and remineralized enamel were: 5.2 +/- 1.1, 8.1 +/- 1.2 and 5.6 +/- 0.8, respectively, in the in vitro study, and 5.3 +/- 0.3, 16.5 +/- 4.7 and 6.5 +/- 2.5, respectively, in the in situ study, values for demineralized enamel being significantly higher than for sound and remineralized enamel in both studies. However, LF was correlated with Delta KHN only in situ. LF was capable of monitoring de- and remineralization in early lesions in situ, when bacteria are presumably present in the caries lesion body, but is not correlated with mineral changes in bacteria-free systems. Copyright (C) 2009 S. Karger AG, Basel

Deposition of Lead and Cadmium Released by Cigarette Smoke in Dental Structures and Resin Composite

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)