Alteración de la mineralización de tejidos dentarios y paradentarios inducida por bifosfonatos en ratas Wistar / Alteration of mineralization of dental and paradental tissues induced by biphosphonates in Wistar rats

Desórdenes sistémicos de la homeostasis mineral o fallas en la mineralización de la matriz extracelular pueden afectar tanto a las piezas dentarias como a su aparato de sostén, conduciendo al fracaso de los tratamientos odontológicos. Existe poca evidencia científica sobre modelos animales que permitan es-tudiar la respuesta de tejidos dentarios/paradenta-rios frente a este tipo de desórdenes. El objetivo del presente trabajo fue estudiar experimentalmente al-teraciones de la biomineralización inducidas por bis-fosfonatos en ratas Wistar. Para ello, 20 ratas Wistar hembras y machos (35±10 g) fueron tratados con 20 mg/kg de etidronato bisódico (EHBP) o solución fi-siológica (control) vía intraperitoneal 5 veces por se-mana durante 3 semanas. Luego de la eutanasia, se extrajeron las mandíbulas para su procesamiento y análisis histológico (H&E). Mediante microfotografías digitales se evaluó: área ósea/área total, espesor de ligamento periodontal, áreas de dentina y de cemen-to. Los resultados se analizaron estadísticamente mediante el test T de Student para comparaciones entre grupos y el test ANOVA de 2 vías para las com-paraciones intersexo. Los grupos EHBP presentaron mayor proporción de osteoide, dentina y cemento no mineralizados respecto a los controles, siendo más marcadas las diferencias en las hembras. Las hem-bras del grupo EHBP mostraron una disminución significativa en el espesor del ligamento periodontal respecto de los controles, aunque esta tendencia no se observó en machos. Los resultados del presente estudio demuestran que el EHBP, en la dosis y tiempo estudiados, altera los procesos de biomineralización tanto del tejido óseo como de los tejidos dentarios (AU)

Systemic disorders of mineral homeostasis or alterations in the mineralization of the extracellular matrix can affect both dental and supportive tissues, leading to the failure of dental treatments. There is a lack of scientific information about animal models that allow to study the response of dental/paradental tissues in this type of disorders. The aim of the present work was to study the biomineralization alterations induced by bisphosphonates in Wistar rats and to study the response of dental and paradental tissues. Twenty Wistar rats (35±10 g) were divided in control (females, males) and EHBP (females, males) groups. The EHBP group received 20 mg/kg of ethidronate bisodium intraperitoneally 5 times a week for 3 weeks, while the control group received saline solution. After euthanasia, mandibles were resected and processed histologically to obtained oriented sections for H&E staining. Photomicrographs were used to evaluate: Bone area/total area, periodontal ligament thickness, dentin and cement area. Results were statistically analyzed using the Student's T test for comparisons between groups and the 2-way ANOVA test for male and female comparisons. The EHBP groups showed a higher amount of non-mineralized osteoid, dentin and cement compared to control groups, being more evident in females. Females in the EHBP group showed a significant decrease in periodontal ligament thickness compared to controls, although this profile was not observed in males. The results of the present study demonstrate that EHBP, at the dose and time studied, alters the biomineralization processes of both bone and dental tissues (AU)

Exposure to endocrine disruptors and alterations in mineralized tissues: a narrative review / Exposición a disruptores endocrinos y alteraciones en tejidos mineralizados: revisión narrativa

Background: Endocrine Disrupting Chemicals (EDCs) would cause alterations in organs/systems of exposed individuals or their progeny. Objetive: To identify and analyze the main published findings on the effects of exposure to EDCs on teeth, cartilage, and bone. Material and Methods: Two databases were analyzed: Medline and Web of Science. Only observational studies analyzing the effect of EDCs on mineralized tissues published since 2006 were included in the study. Results: 25 articles were selected, most of them involving EDCs pesticides, plasticizers, or personal care products, highlighting organochlorine compounds, bisphenols, phthalates, dioxins, parabens, and perfluoroalkyls. Thirty-six per cent of the studies reported an accumulation of EDCs in teeth or bones, while 64% reported alterations in their development or morphology, mainly at the bone level, primarily affecting their mineral density and size, as well as that of the bones of exposed individuals or their progeny. The type of effect observed was related to the EDCs analyzed, and it seemed to depend on variables such as age, sex, ethnicity/race, and even the metabolic status of the individuals in the different species analyzed. No evidence associated with effects on cartilage was found. Conclusion: EDCs in the environment, at work, or at home, under different exposure routes, are capable of accumulating in teeth and bone, particularly affecting the latter. It is necessary to study the effect of EDCs on mineralized tissues in agro-industrial areas, especially on teeth.

Antecedentes: Los Químicos Disruptores Endocrinos (EDCs) causarían alteraciones en órganos/sistemas de individuos expuestos, o su progenie. Objetivo: Identificar y analizar los principales hallazgos publicados sobre el efecto de la exposición a EDCs en dientes, cartílago y hueso. Material y Métodos: Se analizaron dos bases de datos: Medline y Web of Science, incluyendo solo estudios observacionales publicados desde el 2006, analizando el efecto de los EDCs sobre tejidos mineralizados. Resultados:25 artículos fueron seleccionados, siendo la mayoría de los EDCs pesticidas, plastificantes o productos de cuidado personal, destacando los compuestos Organo-clorados, Bisfenoles, Ftalatos, Dioxinas, Parabenos y los Perfluoroalquilos. Un 36% de los estudios reportaron un acúmulo de EDCs en dientes o huesos, mientras que un 64% informaron de alteraciones en su desarrollo o morfología, particularmente a nivel de huesos, afectando principalmente su densidad mineral y su tamaño, así como el de los individuos expuestos o su progenie. El tipo de efecto observado tuvo relación con el EDCs analizado, pareciendo depender de variables tales como edad, sexo, etnia/raza e incluso el estado metabólico de los individuos, en las diferentes especies analizadas. No se encontraron evidencias asociadas a efectos en el cartílago. Conclusión: Los EDCs en el medio ambiente, ámbito laboral o doméstico, bajo distintas rutas de exposición, son capaces de acumularse en diente y hueso, afectando particularmente a este último. Es necesario estudiar el efecto de los EDCs en los tejidos mineralizados en zonas agroindustriales, particularmente a nivel de dientes.

Whitening toothpaste containing activated charcoal, blue covarine, hydrogen peroxide or microbeads: which one is the most effective?

Abstract The efficacy of whitening toothpastes is questionable and controversial. Clinicians, patients and researchers have expressed concern with whitening toothpastes due to the risk of wearing the dental structure and the potential for disappointment if the advertised cosmetic results are not achieved. Objective: This study compared the whitening performance of toothpastes with different whitening technologies after initial and continued use. Material and Methods: Ninety bovine incisors were stained using a concentrated solution of black tea. They were randomly distributed into 6 groups, according to the toothpaste whitening technology: activated charcoal (B&W), blue covarine (WAD), hydrogen peroxide (LWA), microbeads (Oral B 3D White Perfection - 3DW) and optimized abrasives (XW4D). They were compared to a traditional toothpaste without a whitening agent (TA - control). Specimens underwent a brushing machine with controlled pressure, time and temperature. A calibrated examiner measured the color using a VITA-Classical scale before the first brushing cycle (T0), after the first brushing cycle (TI), and after a brushing cycle that simulates continuous use (TCU). Whitening performance was evaluated by the difference of shades (ΔSGU) between T0-TI and T0-TCU timepoints, using the Kruskal-Wallis and Dunn's non-parametric test. The Wilcoxon test was used to evaluate the cumulative effect (α=0.05). Results: Statistically significant differences were observed between toothpastes in both TI and TCU (p<0.05). The time of use also had a significant effect (p<0.05). Conclusion: Only WAD and 3DW showed whitening performance after the first use (TI). The greatest whitening performance after continuous use was obtained by WAD, followed by LWA and 3DW. The use of conventional toothpaste (TA) promotes no tooth whitening. Clinical relevance: Microbead abrasives (3DW) and blue covarine (WAD) were the active technology tested that presented the best global tooth whitening performance.

Selective COX-2 Inhibitor (Meloxicam) and Tooth-Supporting Bone Quality. A Histomorphometric Study in Rats

Abstract The effects of the non-steroidal anti-inflammatory drugs (NSAIDs) on bone quantity and quality were investigated for years. However, there is lack of information on the impact of NSAIDs on the quality of tooth-supporting alveolar bone in absence of periodontal inflammation. Thus, the aim of this study was to evaluate histometrically the influence of a selective COX-2 NSAID (Meloxicam) on the inter-radicular bone mineral density in rats. Forty-nine adult male Wistar rats were randomly divided into four experimental groups: Subcutaneous injection of 0.9% sterile saline for 15 days (G1; n=12) and 45 days (G2; n=11); and subcutaneous injection of Meloxicam for 15 days (G3; n=13) and 45 days (G4; n=13). Mineral density was histometrically determined in the inter-radicular area of the 1st mandibular molars and data analysis performed by two-way ANOVA (a=5%). Results showed no interaction between time and treatment (p>0.05) and that meloxicam did not affect the alveolar bone density. In contrast, it was found that inter-radicular alveolar bone density increased with time (91.88±3.08% and 92.86±2.38% for groups 15 and 45 days, respectively) (p<0.05). Within the limits of this study, daily administration of a selective COX-2 inhibitor (Meloxicam) did not affect the quality of the inter-radicular alveolar bone in absence of periodontal infection.

Resumo Os efeitos dos fármacos anti-inflamatórios não esteroidais (AINEs) sobre a quantidade e qualidade óssea tem sido investigados ao longo dos anos.Entretanto, há falta de informação sobre o impacto dos AINEs na qualidade do osso alveolar de suporte na ausência de inflamação periodontal. Assim, o objetivo deste estudo foi avaliar, histometricamente, a influência de um AINE seletivo para COX-2 (Meloxicam) na densidade mineral óssea inter-radicular em ratos. Quarenta e nove ratos Wistar, machos e adultos foram divididos aleatoriamente em quatro grupos experimentais: injeções subcutâneas de 0,9% de solução salina estéril por 15 dias (G1, n=12) e 45 dias (G2, n=11); e injeções subcutâneas de Meloxicam por 15 (G3, n=13) e 45 dias (G4, n=13). A densidade mineral foi determinada histometricamente na área inter-radicular dos primeiros molares mandibulares e a análise dos dados realizada por meio de ANOVA (a=5%). Os resultados mostraram nenhuma interação entre tempo e tratamento (p>0,05) e que o meloxicam não afetou a densidade óssea alveolar. Em contraste, foi encontrado que a densidade óssea alveolar inter-radicular aumentou ao longo do tempo (91,88±3,08% e 92,86±2,38% para os grupos 15 e 45 dias, respectivamente) (p<0,05). Dentro dos limites deste estudo, a administração diária de um inibidor seletivo para COX-2 (Meloxicam) não afetou a qualidade do osso alveolar inter-radicular na ausência de infecção periodontal.

Effect of coffe and a cola-based soft drink on the color stability of bleached bovine incisors considering the time elapsed after bleaching

There is no consensus about the waiting time necessary for the patient to start consuming beverages containing colorants again after bleaching. Objective: To evaluate the influence of beverages with coloring agents on bleached bovine incisors considering the time elapsed after bleaching. Materials and methods: Sixty bovine incisors were bleached with 35% hydrogen peroxide for in-office use (Whiteness HP Max) and divided into 10 groups. The color was evaluated with a spectrophotometer (Spectro Shade MICRO) before and after bleaching, employing the CIE-Lab system. After bleaching, the teeth were exposed for 5 min to coffee or cola-based soft drink (CBSD) at different periods after bleaching: 10 min, 1 h, 24 h, 48 h, and 72 h. Color (∆E) and lightness (∆L) variations were obtained from the CIE-Lab coordinates. Data were subjected to two-way ANOVA and Tukey HSD tests (p<0.05). Results: Significant differences were observed between groups for both the ∆L and ∆E values (p<0.001). All specimens presented a decrease in brightness (negative ∆L). The highest ∆E values were observed for teeth stained with a CBSD at 10 min and 1 h (4.12 and 4.16, respectively). Teeth pigmented with coffee presented ∆E values below 3.3 units for all evaluation times. Conclusion: The exposure to coffee after bleaching causes less color changes than the exposure to a CBSD regardless of the time after bleaching. .

Mouthwashes with hydrogen peroxide are carcinogenic, but are freely indicated on the internet: warn your patients!

It all began in Ancient Egypt where people used to bleach their teeth with antiseptic mouthwashes made of urea from human urine. Teeth harmony is promoted by expression of feelings, communication, a real window of the brain and its content! Tooth bleaching products are medicines, not cosmetics! Mouth washing with hydrogen peroxide is an illogical and dangerous procedure! Hydrogen peroxide must be used in one's mouth only when employed by a dentist who has been properly instructed to protect the mucosa, preventing it from receiving these products. How and for how long these products are going to be used require caution in order to avoid or decrease any adverse effects on the tissues. Many websites instruct people on how to purchase and prepare hydrogen peroxide so that it is used as an antiseptic mouthwash and tooth bleaching agent. Some websites even refer to dentists as "exploiters", accusing them of not instructing patients properly. In this article, we aim at providing evidence and information upon which dentists and assistants may base their thinking as well as their opinion and procedures regarding "the indiscriminate and free use of hydrogen peroxide in the mouth, on teeth and oral mucosa". Those websites, blogs and social network profiles trespass the limits of public trust and should be immediately sued by the government for committing a crime against public health.

Tudo começou no Egito antigo, onde procurava-se clarear os dentes com bochechos antissépticos com ureia da urina humana. Os dentes se harmonizam com expressões de sentimentos, na comunicação, como uma verdadeira vitrine do cérebro e seus conteúdos! Clareadores dentários são medicamentos, e não cosméticos! Bochecho com água oxigenada representa um procedimento improcedente e perigoso! O uso do peróxido de hidrogênio ou água oxigenada na boca deve ser feito diretamente pelo profissional da Odontologia, treinado para proteger as mucosas contra o contato desses produtos. O tempo e a forma de uso requerem cuidados, para se proteger ou diminuir os efeitos indesejáveis sobre os tecidos. Vários websites "ensinam" como adquirir e preparar água oxigenada para fazer bochechos antissépticos e clarear os dentes. Alguns websites se referem ao profissional da Odontologia como um "explorador", por não ensinar isso ao paciente. No presente artigo, procuraremos informar e dar fundamentos para que os profissionais da Odontologia e auxiliares possam embasar suas reflexões, opiniões e condutas relacionadas ao tema "uso indiscriminado e livre de peróxido de hidrogênio na boca sobre os dentes e mucosa bucal". Esses websites, blogs e perfis em redes sociais abusam da fé pública e deveriam ser acionados judicialmente, imediatamente, pelas autoridades públicas, pelo crime contra a saúde das pessoas.

Radioprotective Effect of Sodium Selenite on Developing Teeth

Radioprotective agents like selenium are used to reduce the damage caused by radiation in healthy tissues. The aim of this study was to evaluate the effect of sodium selenite on the development of the molars of offspring of rats irradiated during odontogenesis. Twenty pregnant rats were randomly divided into 4 groups: control, irradiated, selenium and selenium/irradiated. The selenium and selenium/irradiated groups received 0.3 mg/kg of sodium selenite at 18 days of pregnancy. The rats of the irradiated and selenium/irradiated groups received a single dose of 4 Gy of X rays on the abdominal region at the 19th day of pregnancy. The offspring was sacrificed at 3 and 4 days after birth for evaluation of the birefringence of the enamel organic matrix, and at 30 days for evaluation of the intercuspal dimensions of the molars. The selenium/irradiated group was similar to the irradiated group with respect to the thickness and irregularity of the enamel organic matrix region in the evaluated birefringence, as the intercuspal dimensions of the molars. In conclusion, sodium selenite had no radioprotective action on the development of the molars of offspring of rats irradiated during odontogenesis and had a toxic effect in the initial time.

Agentes radioprotetores, como o selênio, são utilizados para reduzir os danos causados pela radiação nos tecidos sadios. O objetivo nesse estudo foi avaliar o efeito do selenito de sódio no desenvolvimento de molares de filhotes de ratas irradiadas. Vinte ratas grávidas foram aleatoriamente divididas em 4 grupos: controle, irradiado, selênio e selênio/irradiado. Os animais dos grupos selênio e selênio/irradiado receberam 0.3 mg/kg de selenito de sódio aos 18 dias de gestação. Os animais dos grupos irradiado e selênio/irradiado receberam dose única de 4 Gy de radiação X na região abdominal aos 19 dias de gestação. Os filhotes foram sacrificados aos 3 e 4 dias após o nascimento para avaliação da birrefringência da matriz orgânica do esmalte, e aos 30 dias para avaliação das dimensões dos molares. Os resultados do grupo selênio/irradiado foram similares aos do irradiado, tanto em relação à espessura e irregularidade região da matriz orgânica do esmalte quanto às dimensões dos molares. Dessa forma, foi possível concluir que o selenito de sódio não exerceu ação radioprotetora no desenvolvimento de molares de filhotes de ratas irradiadas durante a odontogênese e apresentou efeito tóxico nos tempos iniciais.

Evaluation of the remineralization potential of amorphous calcium phosphate and fluoride containing pit and fissure sealants using scanning electron microscopy.

Aim: To evaluate the remineralization potential of Amorphous Calcium Phosphate (ACP) and Fluoride containing pit and Fissure Sealants using Scanning Electron Microscopy. Materials and Methods: Thirty maxillary first premolars were divided into three groups of ten each and were randomly selected for ACP containing (Aegis- Opaque White, Bosworth Co. Ltd.), Fluoride containing (Teethmate F1 Natural Clear, Kuraray Co. Ltd.), resin based (Concise- Opaque White, 3M ESPE Co. Ltd.) pit and fissure sealant applications. The Concise group served as a control. The teeth weresubjected to the pH-cycling regimen for a period of two weeks. After two weeks, the teeth were sectioned bucco-lingually into 4mm sections and were observed under Scanning Electron Microscope at 50X, 250X, 500X, 1000X and 1500X magnifications. The qualitative changes at the tooth surface and sealant interface were examined and presence of white zone at the interface was considered positive for remineralization. Results: Both ACP containing (Aegis) and Fluoride containing (Teethmate F1) group showed white zone at the tooth surface-sealant interface. The resin based group (Concise) showed regular interface between the sealant and the tooth structure, but no clear cut white zone was observed. Conclusion: Both, Aegis and Teethmate F1 have the potential to remineralize. Release of Amorphous Calcium Phosphate molecules in Aegis group and formation of Fluoroapetite in Teethmate F1 group, were probably responsible for the remineralization.

Effect of lithium on the developing teeth of rabbits

The objective of the present study was to evaluate the changes in the dimensions of the teeth in new born babies of the mothers who receive lithium for a long time during pregnancy. The incidence of congenital defects due to Lithium was studied because, oral and dental structures are frequently the sites of adverse drug reactions. These include salivary glands, oral mucosa, periodontal tissues, teeth, alveolar bone, and other structures. The study was conducted on the female rabbits, which were kept on this specific drug during pregnancy. The off springs of these treated female rabbits were used for research purpose. They were sacrificed and the teeth were examined for the congenital defects developed during intrauterine life. This study was expected to provide suggestions for the use of this drug during pregnancy. The results showed large variations by analysing statistically in the different teeth i.e. the size reduced in maxillary incisors, first and second molars only. The nature of the insult is unlikely to be determinable and the results are generally not in accordance with the predicted outcome. However, the drugs should be used by doctor's prescription only, especially during pregnancy, avoiding the teratogenic effect on the dentition of the new borns

In vitro effect of different concentrations of iron on the initiation of dental caries: pilot study

Previous animal studies have shown that iron reduced the incidence of dental caries. The purpose of this in vitro study was to examine the effect of different concentrations of iron-supplement on the initiation of dental caries on human teeth. Sixty extracted human premolar teeth were randomly distributed into five groups [12/group]. Positive control group [Group 1] did not receive any iron. Experimental groups consisted of adding iron in 100%, 50%, 25% and 12.5% concentrations as Groups 2, 3, 4, and 5 respectively. Mutans Streptococci [MS] bacteria [6715] grown in Todd Hewitt Broth were used. The teeth were placed in 24-well ELISA plates [two groups / plate]. On each well, a media consisting of iron [for experimental groups], bacteria and 10% sucrose was added and changed daily for 29 days. Daily assessment of any decalcification and cavitation was done. All groups receiving iron developed significantly fewer decalcification and carious lesions compared with the positive control. In addition, no cavitation was seen in all the experimental groups during the study period. It is concluded that iron may have some protective action against the development of dental caries in human teeth

Influência de diferentes meios de armazenamento de dentes extraídos na infiltraçäo marginal / Influence of various storage solution on microleakage

A finalidade deste estudo foi a de comparar o efeito de diferentes meios de armazenamento de dentes humanos recém-extraídos e de bovinos na infiltraçäo marginal gengival de restauraçöes de resina composta. Foram selecionados 30 dentes terceiros molares humanos estraídos hígidos e 20 dentes bovinos, divididos em 8 grupos e armazenados nas seguintes condiçöes: Grupo I - dentes humanos em freezer até 20 dias; grupo II - dentes humanos em formol a 10 por cento em geladeira; grupo III - dentes humanos em azida sódica 0,02 por cento em geladeira; grupo IV - dentes humanos em soro fisiológico em geladeira; grupo V - dentes humanos em água destilada à temperatura ambiente; grupo VI - dentes humanos deixados secos durante 2 meses e rehidratados 1 semana em água comum à temperatura ambiente; grupo VII - dente bovino em freezer por 1 ano; grupo VIII - dente bovino em freezer por 20 dias. Foram realizados preparos Classe V em esmalte nas faces V e L de cada dente humano e na face V do dente bovino com a ponta diamantada 1092 (KG Sorensen), num total de 80 preparos. Os preparos foram restaurados com o sistema Single Bond e a resina composta Z100 (3M). Os dentes foram submetidos à termociclagem de 300 ciclos entre ñ 5ºC e 55ºC. O corante utilizado foi a Rodamina B - 0,2 por cento e o grau de infiltraçäo marginal foi analisado em Lupa Estereoscópica utilizando escores de 0 a 4. Foi aplicada a análise estatística de Kruskal-Wallis. Conclusäo: Dentes bovinos armazenados em freezer por 20 dias mostraram o menor grau de infiltraçäo marginal; dentes humanos armazenados em água destilada e dentes secos rehidratados induziram o maior grau; os demais meios de armazenamento mostraram desempenho intermediário

Evaluacion de la limpieza y desinfeccion del conducto radicular con diferentes irrigantes. Parte I / Evaluation of cleaning and desinfection of root canal with different irrigants. Part I

El objetivo de este trabajo fue evaluar el efecto antimicrobiano de soluciones de hipoclorito de sodio al 2,5 por ciento, clorhexidina al 0,12 y 0,2 por ciento en conductos radiculares inoculados con Streptococcus mutans. Se seleccionaron 42 piezas dentarias humanas, recientemente extraidas que fueron cortadas, descartandose sus coronas clinicas, y sellados los apices de las raices a utilizar. Estas se esterilizaron en autoclave a vapor de agua a 130§C durante 30 minutos, y fueron luego inoculadas con 1 ml de un cultivo de 48 horas de la cepa 6715 de Streptococcus mutans suspendidas en caldo Todd Hewitt. El control se realizo colocando un cono de papel esteril en la luz de los conductos durante 5 minutos, fue luego colocado en tubos de ensayo conteniendo caldo Todd Hewitt en cantidad de 5 ml. Los mismos se incubaron a 37§C durante 48 horas en condiciones de anaerobiosis facultativa. Los especimenes se instrumentaron con limas tipo K (Maillefer, Suiza) desde la N§10 a la N§40. Para la irrigacion se dividieron aleatoriamente en cuatro grupos, a saber: Grupo 1 (control) se irrigo con agua destilada, Grupo 2 se irrigo con hipoclorito de sodio al 2,5 por ciento, Grupo 3 con clorhexidina al 0,12 por ciento y Grupo 4 con clorhexidina al 0,2 por ciento. Los controles de los diferentes antisepticos o del agua destilada se realizaron utilizando la misma metodologia que para los controles de inoculos. Los resultados fueron los siguienes: el Grupo 1 (control) evidencio desarrollo en el 100 por ciento de los especimenes. Cuando se utilizo hipoclorito de sodio al 2,5 por ciento, Grupo 2, ausencia de desarrollo bacteriano en el 100 por ciento de los especimenes, con diferencias significativas en el Pre control de inoculo (P<0,a)69,23 por ciento de cultivos positivos cuando se aplico gluconato de clorhexidina al 0,12 por ciento, Grupo 3, con tendencia a la disminucion sin diferencias significativas. Cuando se aplico solucion de gluconato de clorhexidina al 0,2 por ciento, Grupo 4, se observo desarrollo microbiano en el 20 por ciento de los especimenes con diferencias significativas con el Pre condicion basal (P<0,5). en las condiciones experimentales de este trabajo el efecto antimicrobiano fue mayor con solucion de hipoclorito de sodio al 2,5 por ciento, luego con solucion de gluconato de clorhexidina al 0,2 por ciento y por ultimo con solucion de gluconato de clorhexidina al 0,12 por ciento

Dental concerns for vital bleaching of teeth

Esthetic interest of dental professionals have been aroused due to easy conservative technique for bleaching of vital teeth. Most commonly used technique for bleaching is the use of night guards with 10% carbamide peroxide preparations [multiple products are available]. This is commonly known as home bleaching. For in-office vital bleaching, 30% hydrogen peroxide is used. The purpose of this article is to inform dental health care deliverer about safety of the products used in office and as home bleaching agents. This information is based on past researches. These researches were also done to determine the effects of above mentioned bleaching products also on tissue healing and plaque control. Main assessment is based on research work conducted at the dental school, UNC by Van B Haywood

Histological study of the effect of methotrexate on rat teeth development

Fifty rats aged four days were divided into five groups: Group I was the control group, groups II-V animals were given intraperitoneal methotrexate injection with escalating doses [2.1, 3.5, 8.4 and 14 mug/g body weight]. The animals were observed for gross changes and were decapitated at two weeks after injection. Skull radiographs were taken and tooth germs were dissected and submitted for histological study. All rats of groups IV and V died in less than one week with growth arrest. 40% of group III died within two weeks. The LD50 = 4.9 mug/g body weight and LD10 = 1.9 mug/g body weight. Reduction in the average weight of groups II and III rats compared with the control group was observed, which was dose dependent [F = 112.6882, P <0.0001]. Radiographically and histologically, there was delay in dental eruption with disturbances of odontogenesis that were dose related. Methotrexate in non-lethal doses causes a dose-related reduction in growth and dental development. The proliferating undifferentiated mesenchymal cells are more sensitive to methotrexate than odontogenic epithelium

Chemotherapy/radiotherapy: effects on dental growth and development

Paediatric oncology patients receiving chemoradiation therapy often develop dental developmental anomalies which may affect the future dental care. Chemoradiation therapy may cause tooth and root agenesis, root shortening and thinning and localized enamel defects. These enamel defects histologically appear as niches in the developing dentin which alters the overlying enamel. The odontogenic cell sensitivity depends upon the position in the cell cycle and mitotic activity at the time of chemoradiation therapy. It is, therefore, important for the clinician to have the knowledge of the stages of dental development at the time of oncology treatment. The type of therapy to allow him to predict the eventual dental effects and to plan future dental care

Estudo histomorfológico sobre reimplante mediato de incisivo superior de rato. Efeitos da conservaçäo do dente em glicerina à 98 por cento / Histomorphologic study on mediate replant of superior incisor in rats. Effect of tooth preservation in glycerol

Tendo em vista as boas propriedades da glicerina como agente de preservaçäo de tecidos, foi avaliado neste trabalho, os efeitos desta substância sobre reimplantes dentais mediatos. Foram empregados 24 ratos divididos em 2 grupos de 12. No grupo I, o incisivo superior direito, após extraçäo foi mantido durante 48 horas em soro fisiológico. A seguir, foi removida a polpa, o canal obturado com hidróxido de cálcio e reimplantado em seu respectivo alvéolo. No grupo II, o dente foi conservado em glicerina à 98 por cento durante o mesmo período e após mesmo procedimento do grupo anterior, foi reimplantado em seu respectivo alvéolo. Em número de 6 para cada grupo, os ratos foram sacrificados após 20 e 60 dias. As peças obtidas após processamento laboratorial de rotina foram incluídas em parafina. Os cortes foram corados pela hematoxilina e eosina e pelo tricrômico de Masson. Os dentes conservados em glicerina, quando comparados ao soro fisiológico, mostraram menor migraçäo da aderência epitelial e reabsorçäo cemento-dentária mais discreta após 60 dias. Além disso, o ligamento periodontal encontrava-se mais organizado

Estudio comparativo de microdurezas en esmalte y dentina de dientes humanos / Comparative study of enamel and dentine micro hardness in human tooth

Se realiza un estudio comparativo de microdureza en esmalte y dentina no fluorados y fluorados con una solución de NaF 0,05 por ciento, pH 6.7, incubados a 37§C durante 3 horas. Los ensayos de microdureza Vickers se realizaron en cortes de dientes, utilizando las mismas zonas de indentación antes y después de fluorar las muestras. Los resultados obtenidos indican un aumento en la microdureza del esmalte de un 10,89 por ciento y de un 5,8 por ciento para la dentina después de tratarlos con la solución de NaF, diferencia estadísticamente significativa (Test. t para muestras pareadas)