Analysis of the antimicrobial and anti-caries effects of TiF4 varnish under microcosm biofilm formed on enamel

Abstract Titanium tetrafluoride (TiF4) is known for interacting with enamel reducing demineralization. However, no information is available about its potential antimicrobial effect. Objectives This study evaluated the antimicrobial and anti-caries potential of TiF4 varnish compared to NaF varnish, chlorhexidine gel (positive control), placebo varnish and untreated (negative controls) using a dental microcosm biofilm model. Material and Methods A microcosm biofilm was produced on bovine enamel previously treated with the varnishes, using inoculum from human saliva mixed with McBain saliva, under 0.2% sucrose exposure, for 14 days. All experiments were performed in biological triplicate (n=4/group in each experiment). Factors evaluated were: bacterial viability (% dead and live bacteria); CFU counting (log10 CFU/mL); and enamel demineralization (transverse microradiography - TMR). Data were analysed using ANOVA/Tukey's test or Kruskal-Wallis/Dunn's test (p<0.05). Results Only chlorhexidine significantly increased the number of dead bacteria (68.8±13.1% dead bacteria) compared to untreated control (48.9±16.1% dead bacteria). No treatment reduced the CFU counting (total microorganism and total streptococci) compared to the negative controls. Only TiF4 was able to reduce enamel demineralization (ΔZ 1110.7±803.2 vol% μm) compared to both negative controls (untreated: ΔZ 4455.3±1176.4 vol% μm). Conclusions TiF4 varnish has no relevant antimicrobial effect. Nevertheless, TiF4 varnish was effective in reducing enamel demineralization under this model.

The anti-caries activity and toxicity of an experimental propolis-containing varnish

Abstract We investigated the anti-caries effects of an experimental propolis varnish in vivo, and further tested its toxicity against fibroblasts. Fifty-six SPF female Wistar rats were infected with Streptococcus mutans UA159 (SM) and allocated into four groups (n = 14/group): G1, propolis varnish (15%/PV); G2, chitosan varnish (CV/vehicle); G3, gold standard (GS/Duraphat®); and G4, untreated. The animals received a single varnish application on their molars and were submitted to a high cariogenic challenge (Diet-2000, 56% sucrose, and 5% sucrose-added water, ad libitum) for 4 weeks. Total cultivable microbiota and SM were counted, and smooth-surface and sulcal caries were scored. PV, CV and GS cytotoxic effects were tested against fibroblasts. The data were analyzed using ANOVA with the Tukey-Kramer test (p ≤ 0.05). Total microbiota and SM counts did not differ among the treatments (p = 0.78), or in relation to the untreated group (p = 0.52). PV reduced development of smooth-surface enamel caries compared with the untreated group (p = 0.0018), with no significant difference from GS (p = 0.92); however, the PV effects were no longer observed when the dentin was affected. Neither PV nor GS prevented enamel sulcal lesion onset, but GS significantly reduced the severity of dentinal sulcal lesions (p < 0.0001). No significant difference was observed in fibroblast viability between PV and GS (p < 0.0001). In conclusion, PV prevented smooth-surface enamel caries and showed low cell toxicity. Nevertheless, due to the high cariogenic challenge, its effects were not sustained throughout the experiment. Further studies are encouraged to establish a protocol to sustain the long-term anti-caries activity of PV in the oral cavity.

Antimicrobial activity of ozone and NaF-chlorhexidine on early childhood caries

Abstract An early childhood carie (ECC) is an extremely destructive form of tooth decay. The aim of this study was to investigate the action of ozone (O3), and the association of sodium fluoride (NaF) with chlorhexidine (CHX) on bacteria related to ECC. Overnight culture of the bacteria was performed. On exponential phase the suspension was adjusted (101-108 CFU/mL). A drop (10μL) of each concentration of bacteria was applied on sheep blood agar plates and treated with O3 (2, 20, 200, and 2,000 ppm); after 18 hours, recovery analysis of CFU verified the reduction of bacterial activity. For NaF-CHX, sterile 96-well plates were prepared and divided into groups: G1 (150 µL TSB); G2 (20 µL of bacteria + 25 µL CHX + 25 µL NaF); and G3 (150 µL TSB + 20 µL of bacteria + 50 µL water). The plates were verified by analysis of the optical density (0, 12, 14, 16, and 18 hours). The data from O3 test were submitted to ANOVA and Tukey’s test (p < 0.05). For the data from NaF-CHX, the ANOVA 2-way and Bonferroni’s test (p < 0.05) were used. The number of CFU/mL showed death > 3log10 (99.9%) for all bacteria (ozone ≥ 20ppm), while the combination of NaF-CHX was more effective (p < 0.001) compared to each substance tested alone and the control group. The antimicrobial agents tested were able to inhibit all bacteria tested; O3 seemed to be a good alternative for controlling progression of carious lesions, while the association of NaF-CHX showed to be a good antimicrobial with easy and inexpensive application.

In situ effect of titanium tetrafluoride varnish on enamel demineralization

Abstract The effect of a 4% titanium tetrafluoride (TiF 4 ) varnish on enamel demineralization was evaluated. Twelve volunteers participated in this double-blind, randomized crossover study. Six enamel specimens were positioned in intraoral appliances throughout four treatment stages: 4% TiF 4 varnish (experimental varnish), 5% sodium fluoride (NaF) varnish (Duraphat ® ), placebo varnish, and negative control (deionized water). After 24 h, the varnishes were removed and plaques were allowed to accumulate. A 20% sucrose solution was dripped onto enamel blocks (10x/day). Enamel alterations were analyzed by surface microhardness (SMH), percentage of surface loss (%SML), cross-sectional microhardness (CSMH), scanning electron microscopy (SEM), and energy dispersive X-ray spectrometry (EDS). Student's paired t-test was used for SMH analysis and repeated-measures analysis of variance (ANOVA) for %SML and CSMH (∆Z) analyses (p-value=0.05). The TiF 4 varnish group had lower %SML than the placebo and control groups (p=0.044 and p=0.003, respectively), thus showing its capacity to inhibit surface demineralization. TiF 4 and NaF varnishes demonstrated a protective effect against mineral loss on the enamel subsurface. Both were statistically different from the control group when CSMH was analyzed (p=0.000). A titanium dioxide film was observed on enamel surfaces of the TiF 4 group SEM images. EDS confirmed the presence of titanium in all TiF 4 samples. The 4% TiF 4 varnish is a promising compound capable of reacting with enamel to protect it against surface and subsurface demineralization.

Effects of fluoride on proliferation and mineralization in periodontal ligament cells in vitro

Fluoride, which is often added to toothpaste or mouthwash in order to protect teeth from decay, may be a novel therapeutic approach for acceleration of periodontal regeneration. Therefore, we investigated the effects of fluoride on proliferation and mineralization in human periodontal ligament cells in vitro. The periodontal ligament cells were stimulated with various concentrations of NaF added into osteogenic inductive medium. Immunohistochemistry of cell identification, cell proliferation, alkaline phosphatase (ALP) activity assay, Alizarin red S staining and quantitative real-time-polymerase chain reaction (RT-PCR) were performed. Moderate concentrations of NaF (50-500 μmol/L) had pro-proliferation effects, while 500 μmol/L had the best effects. ALP activity and calcium content were significantly enhanced by 10 μmol/L NaF with osteogenic inductive medium. Quantitative RT-PCR data varied in genes as a result of different NaF concentrations and treatment periods. We conclude that moderate concentrations of NaF can stimulate proliferation and mineralization in periodontal ligament cells. These in vitro findings may provide a novel therapeutic approach for acceleration of periodontal regeneration by addition of suitable concentrations of NaF into the medication for periodontitis treatment, i.e., into periodontal packs and tissue patches.

TiF4 and NaF varnishes as anti-erosive agents on enamel and dentin erosion progression in vitro

Objective This study assessed the effect of fluoride varnishes on the progression of tooth erosion in vitro. Material and Methods: Forty-eight enamel and 60 root dentin samples were previously demineralized (0.1% citric acid, pH 2.5, 30 min), leading to a baseline and erosive wear of 12.9 and 11.4 µm, respectively. The samples were randomly treated (6 h) with a 4% TiF4 varnish (2.45%F-, pH 1.0), a 5.42% NaF varnish (2.45%F-, pH 5.0), a placebo varnish and no varnish (control). The samples were then subjected to erosive pH cycles (4x90 s/day in 0.1% citric acid, intercalated with artificial saliva) for 5 days. The increment of the erosive tooth wear was calculated. In the case of dentin, this final measurement was done with and without the demineralized organic matrix (DOM). Enamel and dentin data were analyzed using ANOVA/Tukey’s and Kruskal-Wallis/Dunn tests, respectively (p<0.05). Results The TiF4 (mean±s.d: 1.5±1.1 µm) and NaF (2.1±1.7 µm) varnishes significantly reduced enamel wear progression compared to the placebo varnish (3.9±1.1 µm) and control (4.5±0.9 µm). The same differences were found for dentin in the presence and absence of the DOM, respectively: TiF4 (average: 0.97/1.87 µm), NaF (1.03/2.13 µm), placebo varnish (3.53/4.47 µm) and control (3.53/4.36 µm). Conclusion The TiF4 and NaF varnishes were equally effective in reducing the progression of tooth erosion in vitro. .

In Situ Effect of Titanium Tetrafluoride and Sodium Fluoride on Artificially Decayed Human Enamel

This study compared in situ the application of 4% titanium tetrafluoride (TiF4) solution and 2% sodium fluoride (NaF) gel on artificial white-spot lesions in human enamel. A crossover, double-blind study using in situ caries models was carried out. Eleven volunteers used an intraoral appliance containing five demineralized human enamel blocks. The blocks (n=170) were randomly divided according to treatment into the following groups: TiF4 (n=55), NaF (n=55), positive control (n=55). A negative control group was composed of demineralized specimens (n=5). The microhardness test was performed using a Knoop penetrator. Energy dispersive spectrometer (EDS) was used to analyze the concentration of titanium, calcium, phosphate and oxygen. The enamel microhardness at different depths for TiF4, NaF and positive control samples was not statistically different (p>0.05). The samples from these three groups had statistically higher microhardness values than the negative control samples (p<0.05). EDS analysis did not provide conclusive results about the penetration of titanium in the TiF4 samples. While in some fragments it had substantial penetration, in other fragments it only had superficial penetration. It was possible to conclude that, under in situ conditions, 4% TiF4 solution and 2% NaF gel were able to remineralize artificial white-spot lesions in human enamel. However, the magnitude of the remineralization did not differ between groups.

Este estudo comparou in situ a aplicação de uma solução de tetrafluoreto de titânio (TiF4) a 4% e um gel de fluoreto de sódio (NaF) sobre lesões de mancha branca artificiais em esmalte dentário humano. Foi realizado um estudo cruzado, duplo-cego utilizando um modelo in situ de cárie. Onze voluntários usaram um aparelho intraoral contendo cinco blocos de esmalte humanos desmineralizados. Os blocos (n = 170) foram divididos aleatoriamente de acordo com o tratamento nos seguintes grupos: TiF4 (n = 55) , NaF (n = 55) , controle positivo (n = 55). Um grupo controle negativo foi composto de espécimes desmineralizados (n = 5). O teste de microdureza foi realizado utilizando um penetrador Knoop. Espectrômetro de energia dispersiva (EDS) foi utilizado para analisar a concentração de titânio, cálcio, fosfato e oxigênio. A microdureza do esmalte em diferentes profundidades para as amostras dos grupos TiF4, NaF e controle positivo não diferiram estatisticamente (p>0,05). As amostras destes três grupos apresentaram valores de microdureza estatisticamente maiores do que as amostras do controle negativo (p<0,05). A análise EDS não forneceu resultados conclusivos sobre a penetração de titânio nas amostras de TiF4. Apesar de apresentar, em alguns fragmentos, uma penetração substancial, em outros fragmentos apresentou apenas penetração superficial. Foi possível concluir que, sob as condições do estudo in situ, a solução de TiF4 a 4% e o gel de NaF a 2% foram capazes de remineralizar lesões de mancha branca em esmalte humano. No entanto, a magnitude da remineralização não diferiu entre os grupos.

Effects of fluoride and ethanol administration on lipid peroxidation systems in rat brain.

Exposure to fluoride and excessive ethanol consumption has been identified as a serious public health problem in many parts of the world, including India. Thus, the effect of co-exposure to fluoride and ethanol for 3-6 weeks was studied on lipid peroxidation (LPO) and oxidative stress related parameters in the rat brain. After 3 weeks, co-treated animals showed 95% increase in LPO levels compared to control. However, the levels of reduced glutathione, total and protein thiols were decreased. These changes were accompanied by a decrease in the activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glutathione-S-transferase. Rats exposed to fluoride together with ethanol for 6 weeks resulted in 130% increase in LPO and decrease in the reduced glutathione levels. The activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glutathione-S-transferase were reduced under these conditions. Brain histology revealed excessive lymphocytes, edema and spongeosis in the cortical region after six weeks of fluoride and ethanol treatment. These results suggest that exposure to fluoride together with ethanol enhances lipid peroxidation by affecting antioxidant defence systems in the rat brain.

Fluoride modulates preosteoblasts viability and matrix metalloproteinases-2 and -9 activities

This study evaluated the influence of fluoride on cell viability and activity of matrix metalloproteinases (MMP) -2 and -9 secreted by preosteoblasts. Preosteoblasts (MC3T3-E1 murine cell line) were cultured in MEM medium supplement with 10% Fetal Bovine Serum (FBS) and nucleosides/ribonucleosides without ascorbic acid. Adherent cells were treated with different concentrations of F (as sodium fluoride-NaF) in medium (5 x 10-6 M, 10-5 M, 10-4 M and 10-3 M) for 24, 48, 72 and 96 h at 37ºC, 5% CO2. Control cells were cultivated in MEM only. After each period, preosteoblast viability was assessed by MTT assay. MMP-2 and -9 activities were performed by gel zymography. Also, alkaline phosphatase (ALP) activity was quantified by colorimetry in all experimental groups. It was shown that cultured cells with the highest dose of F (10-3 M) for 96 h decreased preosteoblast viability while lower doses of F did not alter it, when compared to untreated cells. No differences were observed in ALP activity among groups. Moreover, compared to control, the treatment of cells with F at low dose slightly increased MMP-2 and -9 activities after 24 h. It was concluded that F modulates preosteoblast viability in a dose-dependent manner and also may regulate extracellular matrix remodeling.

Neste estudo, buscou-se avaliar a influência do fluoreto (F) na viabilidade celular e atividade das metaloproteinases de matriz (MMP) -2 e -9 secretado pelos pré-osteoblastos. Pré-osteoblastos (linhagem celular MC3T3-E1 murina) foram cultivados em meio MEM suplementado com 10% de soro fetal bovino (FBS) e nucleosídeos/ribonucleosídeos sem ácido ascórbico. Células aderidas foram tratadas com diferentes concentrações de F (na forma de fluoreto de sódio-NaF) em meio (5 x 10-6 M, 10-5 M, 10-4 M e 10-3 M) por 24, 48, 72 e 96 h a 37ºC, 5 % de CO2. Células do grupo controle foram cultivadas apenas em MEM. Após cada período, a viabilidade dos pré-osteoblastos foi avaliada por MTT. A atividade das MMP-2 e -9 foram analisadas pela zimografia. Além disso, a atividade da fosfatase alcalina (FA) foi quantificada por colorimetria em todos os grupos experimentais. Foi demonstrado que as células cultivadas com a maior dose de F (10-3 M) no período de 96 h tiveram sua viabilidade comprometida, enquanto doses mais baixas de F não a alteraram significativamente, quando comparado com células não tratadas. Não foi observada diferença na atividade da FA entre os grupos. Além disso, o tratamento de células com F em baixas doses, comparado ao grupo controle, promoveu um pequeno aumento da atividade das MMP-2 e -9 após 24 h. Pode-se concluir que o F modula a viabilidade de pré-osteoblastos de uma maneira dose-dependente e também pode regular a remodelação da matriz extracelular.

S. mutans biofilm model to evaluate antimicrobial substances and enamel demineralization

The aim of this study was to validate a model of S. mutans biofilm formation, which simulated 'feast-famine' episodes of exposure to sucrose that occur in the oral cavity, showed dose-response susceptibility to antimicrobials and allowed the evaluation of substances with anticaries potential. S. mutans UA159 biofilms were grown for 5 days on bovine enamel slabs at 37°C, 10 percent CO2. To validate the model, the biofilms were treated 2x/day with chlorhexidine digluconate (CHX) at 0.012, 0.024 and 0.12 percent (concentration with recognized anti-plaque effect) and 0.05 percent NaF (concentration with recognized anti-caries effect). CHX showed dose-response effect decreasing biomass, bacterial viability and enamel demineralization (p < 0.05). Whereas, 0.05 percent NaF did not show antimicrobial effect but had similar effect to that of 0.12 percent CHX decreasing enamel demineralization (p < 0.05). The model developed has potential to evaluate the effect of substances on biofilm growth and on enamel demineralization.

Effectiveness of Sodium Fluoride as a Glycolysis Inhibitor on Blood Glucose Measurement: Comparison of Blood Glucose using Specimens from the Korea National Health and Nutrition Examination Survey / 대한진단검사의학회지

BACKGROUND: Accurate measurement of blood glucose concentrations is essential for defining diabetes, and the minimization of ex vivo glycolysis has been recommended. Recent guidelines advocate two kinds of methods for sample collection and processing: either the sodium fluoride (NaF) method or immediate refrigeration using a serum separation tube (SST). We investigated the difference between the two methods in measuring subsequent glucose concentrations using blood specimens from participants recruited for the fourth Korean National Health and Nutrition Examination Survey. METHODS: Paired venous blood samples were collected in an SST and a NaF tube from 1,103 men and women. SST serum was separated within 30 min, including standing for 15 min, and then refrigerated. The NaF samples were refrigerated, but not separated until immediately before analysis. We compared the blood glucose concentrations between the SST (SST glucose) and NaF (NaF glucose) methods. RESULTS: The mean SST glucose was significantly higher than NaF glucose (99.0 mg/dL vs 96.5 mg/dL, P<0.05). NaF glucose showed a negative mean bias of 2.6 mg/dL vs SST glucose but showed high correlation (R=0.9899). There was no significant correlation between the bias of blood glucose concentrations by two methods and the storage time of NaF glucose. CONCLUSIONS: The negative bias associated with the use of NaF tubes may significantly affect the prevalence of diabetes. Serum separation and refrigeration within 30 min after venous sampling is recommended over NaF method, not only to minimize the preanalytical impact on detecting diabetes but also to reduce sample volume and number of tubes.

Ondas ultra-sônicas de alta freqüência causam disfunção endotelial em artérias coronárias caninas epicárdicas / High-frequency ultrasonic waves cause endothelial dysfunction on canine epicardial coronary arteries

OBJETIVO: Aplicação de energia por ultra-som pode facilitar a remoção da placa ateromatosa, mas o efeito desse procedimento em vasos próximos ainda é matéria de estudos experimentais. MÉTODOS: Para determinar se a energia ultra-sônica compromete a produção de óxido nítrico, segmentos de artérias coronárias caninas foram expostos a baixos (0-10 W) e altos (25 W) níveis de energia por 15 segundos, utilizando-se protótipo de aparelho para a realização de endarterectomia. Após exposição, segmentos das artérias coronarianas foram estudados em organ chambers. Para os ensaios farmacológicos foram utilizadas as seguintes drogas:difosfato de adenosina (ADP), acetilcolina (Ach) e fluoreto de sódio (NaF) para a avaliação do relaxamento dependente do endotélio. O nitroprussiato de sódio (NPS) e o isoproterenol foram utilizados para a avaliação do relaxamento independente do endotélio. RESULTADOS: A aplicação de alta energia ultra-sônica comprometeu o relaxamento dependente do endotélio induzido por ADP (10-9 - 10-4 M), Ach (10-9 - 10-4 M) e NaF (0,5 -9,5 mM) em artérias coronarianas epicárdicas. Entretanto, baixos valores de energia ultra-sônica não alteraram o relaxamento dependente do endotélio (nem o relaxamento máximo e nem a EC50) induzido pelos mesmos agonistas. O relaxamento da musculatura lisa vascular induzido por isoproterenol (10-9 - 10-5 M) ou NPS (10-9 - 10-6 M) não foi comprometido, tanto por baixos, quanto por altos níveis de energia ultra-sônica. CONCLUSÃO: Os experimentos demonstram que altas energias ultra-sônicas alteram a função endotelial. Entretanto, o ultra-som não altera a habilidade de relaxamento da musculatura lisa vascular de artérias caninas epicárdicas.

OBJECTIVE: Application of ultrasound energy by an endarterectomy probe can facilitate the removal of atheromatous plaque, but the effect of this procedure on surrounding vessel structure and function is still a matter of experimental investigations. METHODS: To determine whether ultrasound energy impairs the production of nitric oxide or damages vascular smooth muscle function, isolated canine epicardial coronary artery segments were exposed to either high (25 W) or low (0-10 W) ultrasonic energy outputs, for 15 seconds, using an endarterectomy device prototype. After exposure, segments of epicardial coronary artery were studied in organ chambers. The following drugs were used: adenosine diphosphate (ADP), acetylcholine (Ach) and sodium fluoride (NaF) to study endothelium-dependent relaxation and sodium nitroprusside (SNP) and isoproterenol to evaluate endothelium-independent relaxation. RESULTS: Application of high ultrasonic energy power impaired endothelium-dependent relaxation to ADP (10-9 - 10-4 M), Ach (10-9 - 10-4 M) and NaF (0.5 - 9.5 mM) in epicardial coronary arteries. However, low ultrasound energy output at the tip of the probe did not alter the endothelium-dependent relaxation (either maximal relaxation or EC50) to the same agonists. Vascular smooth muscle relaxation to isoproterenol (10-9 - 10-5 M) or SNP (10-9 - 10-6 M) was unaltered following exposure to either low or high ultrasonic energy outputs. CONCLUSION: These experiments currently prove that ultrasonic energy changes endothelial function of epicardial coronary arteries at high power. However, ultrasound does not alter the ability of vascular smooth muscle of canine epicardial coronary arteries to relax.

Response of osteoblastic cells to titanium submitted to three different surface treatments / Resposta de células osteoblásticas ao titânio submetido a três diferentes tratamentos de superfície

No complexo processo de formação óssea na interface implante-osso, as propriedades de superfície são um importante fator modulador da função osteoblástica. No presente estudo, foram preparadas amostras de titânio comercialmente puro (cp Ti) com diferentes propriedades de superfície por meio de ataque químico com solução à base de ácido sulfúrico/clorídrico (tratamento A); ataque químico seguido de oxidação anódica com ácido fosfórico (tratamento B); e ataque químico seguido de oxidação térmica e imersão em fluoreto de sódio (tratamento C). As chapas foram caracterizadas por meio de microscopia eletrônica de varredura (MEV), perfilometria e ângulo de contato. O comportamento de células osteoblásticas de camundongo foi acompanhado por três semanas. As células cultivadas sobre os diferentes substratos de titânio apresentaram um modelo de comportamento similar durante as etapas de adesão e espalhamento. No entanto, a proliferação e a diferenciação celulares foram maiores nas amostras submetidas aos tratamentos A e C, que se apresentaram menos rugosas e com energia livre de superfície com menores componentes polares.

Use of vitamin C in delayed tooth replantation

O objetivo deste trabalho foi avaliar microscopicamente, em reimplantes tardios de dentes de rato, os efeitos do tratamento da superfície radicular com diferentes soluções. Foram utilizados 30 ratos Rattus norvegicus albinos da linhagem Wistar que tiveram seus incisivos centrais extraídos e deixados sobre a bancada por 6 h. As polpas foram extirpadas e os canais irrigados com solução de hipoclorito de sódio a 1%. Após o preparo endodôntico, a superfície radicular de cada dente foi tratada com solução de hipoclorito de sódio a 1% por 10 min (trocada a cada 5 min) seguida de soro fisiológico por 10 min, e os dentes foram divididos em três grupos com 10 espécimes em cada um. Nos Grupos I, II e III, respectivamente, a superfície radicular foi tratada com fluoreto de sódio fosfato acidulado a 2%, vitamina C e vitamina C efervescente (2 g, Redoxon®). Após obturação com pasta de hidróxido de cálcio os dentes foram reimplantados e os animais foram sacrificados aos 10 e 60 dias. O Grupo I apresentou maiores áreas de reabsorção por substituição e anquilose. Comparando as formas de vitamina C utilizadas, a efervescente (Grupo III) foi a que apresentou resultados mais favoráveis com mais áreas de anquilose e reabsorção por substituição que áreas de reabsorção inflamatória.

Effect of fluoride and gonadal steroid deficiency on enamel and dentin mineralization of female rats

O objetivo do trabalho foi verificar se a deficiência de estrógenos causava alteração na microdureza do esmalte e da dentina de incisivos de ratas e se a administração crônica de fluoreto alterava essa resposta. Ratas ovariectomizadas ou sham-ovariectomizadas receberam para beber água destilada contendo ou não NaF 10 ppm, durante 90 dias. Decorrido este tempo, os incisivos maxilares foram removidos e a microdureza determinada no esmalte e dentina. Os resultados foram submetidos à análise de variância e teste de Tukey (p<0,05). Constatou-se uma redução significante na mineralização da coroa (7,9% e 8,1%) e raiz (20,4% e 25,0%) nos grupos tratados com fluoreto ou água destilada, respectivamente e um aumento (14,2%) na dentina da coroa, após a ovariectomia. O tratamento com fluoreto não impediu a redução da mineralização no esmalte, porém interferiu na dentina diminuindo a mineralização, após a ovariectomia. Concluiu-se que o processo da mineralização do esmalte e da dentina dos incisivos de ratas sofre a ação de estrógenos, de maneira direta ou indireta e que os dois tecidos respondem de maneiras diferentes à administração de fluoreto.

Effect of 0.02 percent NaF solution on enamel demineralization and fluoride uptake by deciduous teeth in vitro

A aplicação da solução de NaF a 0,02%, no lugar de dentifrício fluoretado, tem sido sugerida para ser aplicada com cotonete nos dentes de bebês para reduzir o risco de fluorose dental. Como o efeito anticariogênico dessa recomendação não tem sido estudado, avaliou-se in vitro seu efeito na redução da desmineralização e incorporação de fluoreto no esmalte de dentes decíduos; dentifrício não fluoretado e fluoretado (1.100 mg F/g) foram utilizados como controles negativo e positivo, respectivamente. O dentifrício fluoretado foi mais efetivo que a solução de NaF a 0,02% na redução de desmineralização e na incorporação de fluoreto no esmalte (p < 0,05). Os dados sugerem que uso alternativo de NaF a 0,02% ao invés de dentifrício fluoretado para reduzir o risco de fluorose dental deve ser reavaliado, especialmente se a cárie dental precisa ser controlada.

Effect of fluoride on human dental pulp cells in vitro.

Human dental pulp cells were cultured in fluoride containing medium of various concentrations (0, 1, 2, 5, 10, 20, 25, 30, 40, 50, 60 and 80 ppm) in order to study the biological effect on the cells' proliferation and alkaline phosphatase (ALP) activities. It was found that fluoride at 5 ppm concentration significantly stimulated cell proliferation and ALP activity between 24 and 48 hours after exposure whereas at higher concentrations (40 - 80 ppm), fluoride significantly inhibited cell growth and ALP activity after 48 hours (Student's t test). The maximum effect was around 80 ppm. These observations suggest that fluoride, if used at a low concentration, may be a useful therapeutic agent for the treatment of pulpal disease by means of stimulating the proliferation and differentiation of dental pulp cells. At higher concentrations, it will have negative effects on this kind of cell.

Estudo microscópico do efeito do tratamento da superfície radicular com acetazolamida em dentes de ratos avulsionados e reimplantados / Microscopic study of the effect of root surface treatment with acetazolamida in avulsed and re-implanted rat teeth

Um dos procedimentos indicados para dentes avulsionados e que seräo reimplantados após trinta minutos fora do alvéolo é o tratamento da superfície radicular. Mesmo com a eliminaçäo do ligamento periodontal ressecado ou danificado e limpeza do canal radicular, os casos de insucessos säo enormes. Frente a isso, este trabalho tem como objetivo tratar a superfície radicular de dentes de ratos avulsionados e reimplantados tardiamente. Para isso, foram utilizados 54 dentes incisivos centrais superiores direitos de ratos, divididos em três grupos. No grupo I, a superfície radicular foi tratada com soluçäo de hipoclorito de sódio a 1 por cento; no grupo II, com soluçäo de hipoclorito de sódio a 1 por cento seguido da aplicaçäo de fluoreto de sódio a 2 por cento; no grupo III, após o uso do hipoclorito de sódio a 1 por cento , foi utilizada a soluçäo de acetazolamida a 5 por cento. Todos os grupos tiveram seus canais preenchidos com pasta de hidróxido de cálcio e, em seguida, os dentes foram reimplantados em seus alvéolos. Passados 15, 60 e 90 dias do reimplante, os animais foram mortos e as peças obtidas, processadas em laboratório para análise em microscópio de luz. Os resultados mostraram que todos os tratamentos testados näo impediram a ocorrência da anquilose e da reabsorçäo radicular

Resistencia al ataque ácido en esmalte dental humano antes y después de la aplicación tópica de tres agentes fluorurados / Resistance to acid attack in human dental enamel before and after topical application of three fluoridated agents

El presente estudio "in vivo" se llevó a efecto en esmalte de dientes permanentes de niños residentes en Cd. Nezahualcóyotl y tuvo como objetivo evaluar, de manera indirecta, por medio de biopsias obtenidas con la técnica de De la Cruz y cols. (1992) la capacidad de tres agentes fluorurados de aplicación tópica para producir, en esmalte, un incremento de la resistencia al ataque ácido. Los agentes evaluados fueron flúor fosfato acidulado (APF) al 1,23 por ciento en gel, fluoruro de sodio (NaF) al 2 por ciento en solución acuosa y un barniz fluorado (BF) al 5 por ciento. Los resultados obtenidos antes de aplicar el APF en gel al 1,23 por ciento presentaron una media de profundidad de biopsia (PB) de 2,695u, una semana después la media fue de 1,0492u, los resultados posteriores fueron de 1,5835u. Por último, en el grupo del BF al 5 por ciento, elaborado en la Facultad de Estudios Superiores Saragoza, tuvo una PB inicial de 2,0492u, y una PB final de 1,2793u. La discusión se establece en términos de los factores que determinan estas diferencias