RESUMEN

Introduction: Natural products are an option to be used in different conditions in the oral cavity, such as Camellia sinensis, which due to its different properties would be beneficial in the erosion of the dental surface. Objetive: Determinar el efecto del extracto de Camellia sinensis (C. sinensis) adicionado con flúor frente a la acción erosiva de ácidos no bacterianos en la superficie de la dentina humana. Materials and Methods: Quasi-experimental, prospective, longitudinal, and in vitro study, consisting of 50 samples of human dentin, which were classified into 5 study groups: distilled water, hydrochloric acid, 2% C. sinensis extract, sodium fluoride. 2% and 2% C. sinensis extract added with 2% sodium fluoride. The surface roughness of each sample was evaluated with the SRT6200 digital roughness meter, obtaining a total average roughness and the measurements were carried out in two moments. Results: It was observed that the 2% C. sinensis extract, the 2% sodium fluoride, and the C. sinensis extract added with 2% sodium fluoride, showed a variation in surface roughness between before and after, which was not significant (p<0.05) in all cases. It should be noted that the C. sinensis plus sodium fluoride group is the one that obtained the best variation in the mean surface roughness than the other groups studied. Conclusions: The 2% C. sinensis extract, 2% sodium fluoride, and the combination of both compounds demonstrated an inhibitory effect against the erosive action of hydrochloric acid (0.01 M) on the dentin surface, not presenting a statistically significant difference in the results.

Introducción: Los productos naturales son una opción para ser usados en diferentes afecciones en la cavidad bucal, como lo podría ser la Camellia sinensis, que por sus diferentes propiedades sería de beneficio en la erosión de la superficie dental. Objetivo: Determinar el efecto del extracto de Camellia sinensis (C. sinensis) adicionado con flúor frente a la acción erosiva de ácidos no bacterianos en la superficie de la dentina humana. Materiales y Métodos: Estudio cuasi experimental, prospectivo, longitudinal ein vitro, constituido por 50 muestras de dentina de dientes permanentes, que se clasificaron en 5 grupos de estudio: Agua destilada, ácido clorhídrico, extracto de C. sinensis a 2%, fluoruro de sodio al 2% y extracto de C. sinensisa 2% adicionado con fluoruro de sodio al 2%. Se evaluó la rugosidad superficial de cada muestra con el rugosímetro digital SRT6200, obteniéndose una rugosidad media total y se realizaron las mediciones en dos momentos. Resultado: Se observó que el extracto de C. sinensisal 2%, el fluoruro de sodio al 2% y el extracto de C. sinensis adicionado con fluoruro de sodio al 2%, presentaron una variación de la rugosidad superficial entre el antes y el después, no siendo esta significativa (p<0.05) en todos los casos. Cabe resaltar que el grupo C. sinensis más fluoruro de sodio, es el que obtuvo una mejor variación de la media de rugosidad superficial, que los otros grupos estudiados. Conclusión: El extracto de C. sinensisal 2%, el fluoruro de sodio al 2% y la combinación de ambos compuestos demostraron un efecto inhibitorio frente a la acción erosiva del ácido clorhídrico (0,01 M) en la superficie de dentina, no presentando una diferencia estadísticamente significativa en los resultados.

Asunto(s)

RESUMEN

Los dientes animales de las diferentes especies (hu- mano, equino, cerdo, etc.) están constituidos histológi- camente por cuatro tejidos fundamentales. Ellos son: esmalte, dentina, cemento y pulpa dental. Su compo- sición, estructura, morfología y tamaño son disímiles para cada género. Según numerosas investigaciones, los dientes de bovino serían los de elección por ser de fácil obtención y por tener muy pocas, o ninguna, diferencias tanto a nivel macro como microscópico con respecto a los dientes humanos. El objetivo de la presente revisión es aportar información actualizada acerca de las características histológicas de los tejidos dentarios bovinos y profundizar el conocimiento de las similitudes y diferencias de los dientes bovinos y humanos dando soporte a otros estudios compa- rativos y promoviendo la utilización de las piezas dentarias bovinas en trabajos de investigación en odontología (AU)

The animal teeth of the different species (human, equine, pig, etc.) are histologically constituted by four fundamental tissues: enamel, dentin, cement and dental pulp. Their composition, structure, morphology and size are dissimilar for each gender. According to numerous investigations, bovine teeth would be the ones of choice because they are easy to obtain and have very few or no differences, both at the macro and microscopic levels, with respect to human teeth. The objective of this review is to provide updated information about the histological characteristics of bovine dental tissues and deepen the knowledge of the similarities and differences between bovine and human teeth, supporting other comparative studies and promoting the use of bovine dental pieces in research work in dentistry (AU)

Asunto(s)

RESUMEN

Electrochemical dissolution is a method in which fluoridated solution in direct contact with the fractured instrument receives an electrical current that speeds up fragment dissolution. The aim of this study was to assess the integrity of dentinal walls during the electrochemical dissolution of fractured rotary endodontic instruments in extracted human teeth. Forty-five human mandibular incisors subjected to the electrochemical dissolution process using fluoride solution with low NaCl concentration (LC group: NaF 12 g/L + NaCl 1 g/L, pH = 5.0), fluoride solution with saturating NaCl concentration (SC group: NaF 12 g/L + NaCl 180 g/L, pH = 5.0) and distilled water (control group) were evaluated. For each group, 15 incisors were submitted for the scanning electron microscopy (SEM) evaluation. The roots were sectioned longitudinally; each hemisection was analyzed (n = 30), and energy-dispersive spectroscopy (EDS) was performed. The amount of dentinal tubule openings was analyzed by SEM. Statistical analyses were performed. The test solutions did not alter the amount of dentinal tubule openings when compared with the control group. No Ni or Ti was impregnated into the dentinal tubules after electrochemical techniques. The dentinal structure remained unchanged following the electrochemical dissolution method.

Asunto(s)

RESUMEN

Dentes bovinos têm sido utilizados como substitutos aos humanos em pesquisas odontológicas. Entretanto, faltam dados que suportem o uso da dentina radicular bovina, sobretudo, que analisem o efeito da idade nas propriedades do substrato. Assim, analisou-se o efeito da idade nos aspectos morfológicos, químicos e físicos das dentinas radiculares humana e bovina, em função dos terços da raiz. Trata-se de um estudo experimental, in vitro, aprovado pelo Comitê de Ética em Pesquisa (COEP-UFMG 1.803.933) e pela Comissão de Ética no Uso de Animais (CEUAUFMG 372/2016). A amostra foi composta por dentes unirradiculares, cujas dentinas radiculares foram categorizadas em: humana jovem (HJ, 20-30 anos); humana madura (HM, acima de 60 anos); bovina jovem (BJ, 24-36 meses); e bovina adulta (BA, acima de 48 meses). Os dentes foram seccionados abaixo da junção amelocementária e ao longo eixo da raiz, para a obtenção de hemisecções. Uma hemisecção foi escolhida e cortes foram feitos para a obtenção dos espécimes, conforme cada método de análise. Para as análises dos aspectos morfológicos ­ número, diâmetro e área dos túbulos dentinários ­ os espécimes foram analisados em Microscópio Eletrônico de Varredura. A composição química foi analisada por Espectroscopia de Raios X por Dispersão em Energia, Espectroscopia por Comprimento de Onda Dispersivo e Espectroscopia Raman por Transformada de Fourier. Na análise das propriedades mecânicas, os espécimes foram submetidos aos testes de nanoindentação, resistência à flexão em três pontos e compressão. Para a análise da resistência ao cisalhamento por extrusão, as raízes receberam tratamento endodôntico e foram fixados pinos de fibra de vidro com cimentos resinosos (dual convencional e autoadesivo). As raízes foram seccionadas nos terços radiculares e os espécimes testados em máquina universal de ensaios. Adicionalmente, avaliou-se o grau de conversão dos cimentos resinosos. Os dados foram analisados em software estatístico, nível de significância de 5%. A HM apresentou os menores valores para número, diâmetro e área de túbulos dentinários (p<0,05). A HM apresentou maiores valores de cálcio, razão Ca/P e concentração mineral relativa, com diminuição na organização e qualidade do colágeno (p<0,05). A HM apresentou os maiores valores de nanodureza, módulo de elasticidade e resistência à compressão, mas os menores valores de resistência à flexão e módulo de elasticidade à flexão (p<0,05). A HM apresentou os menores valores de resistência de união, com diferenças entre os terços radiculares (p<0,05). O grau de conversão dos cimentos apresentou uma diminuição ao longo dos terços radiculares (p<0,05). Concluiu-se que a idade possui um efeito nos aspectos morfológicos, químicos e físicos da dentina radicular humana, sem efeito na dentina bovina. Assim, quando da necessidade de substituição da dentina radicular humana pela bovina em pesquisas, é necessário considerar o efeito da idade nos desfechos analisados.

Bovine teeth have been used as a substitute for human teeth in dental research. However, there is a lack of data that support the use of bovine root dentin, mainly, that analyze the effect of age on the properties of the substrate. Thus, the effect of age on the morphological, chemical and physical aspects of human and bovine root dentin was analyzed, in function of the root thirds. This is an in vitro experimental study, approved by the Research Ethics Committee (protocol number: 1.803.933) and the Ethics Committee on the Use of Animals (protocol number: 372/2016). The sample was composed of single-rooted teeth and root dentin was categorized into: young human (YH, 20-30 years); old human (OH, above 60 years); young bovine (YB, 24-36 months); and adult bovine (AB, over 48 months). The roots were sectioned below the cement-enamel and longitudinally to produce two hemi-sections. One hemi-section was chosen and sections were made to obtain the specimens, according to each method of analysis. For the analyzes of the morphological aspects - number, diameter and area of the dentinal tubules - the specimens were analyzed in Scanning Electron Microscope. The chemical composition was analysed by Energy Dispersive Spectroscopy, Wavelength Dispersive Spectroscopy and Fourier Transformed Raman Spectroscopy. In the analysis of the mechanical properties, the specimens were submitted to nano-indentation, three-point flexural and compression tests. For the analysis of the push-out bond strength test, the roots received endodontic treatment and fiber post with resin cements (conventional and selfadhesive dual) were fixed. The roots were sectioned in the root thirds and the specimens tested in a universal testing machine. Additionally, the degree of conversion of the resin cements was evaluated. The data were analyzed in statistical software, level of significance of 5%. The OH presented the lowest values for number, diameter and area of dentinal tubules (p<0.05). OH showed higher values of calcium, Ca/P ratio and relative mineral concentration, with decrease in the organization and quality of the collagen (p<0.05). The OH showed the highest values of nano-hardness, elastic modulus and compressive strength, but the lowest values of flexural strength and flexural modulus (p<0.05). The OH presented the lowest values of bond strength, with differences among the root thirds (p<0.05). The degree of conversion of the cements showed a decrease along the root thirds (p<0.05). It was concluded that age has an effect on the morphological, chemical and physical aspects of human root dentin, with no effect on bovine dentin. Thus, when it is necessary to replace the human root dentin by the bovine in research, it is necessary to consider the effect of age on the analysed outcomes.

Asunto(s)

RESUMEN

The aim of this study was to evaluate the chemical and morphological effects of different lasers as a final surface treatment for endodontic therapy through energy dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM) respectively. Twenty-five maxillary canines were selected and instrumented with K3 system. Roots were randomly distributed into five groups (n = 5) according to the surface treatment: GI (distilled water), GII (NaOCl + EDTA), GIII (NaOCl + EDTA + 980 nm diode laser), GIV (NaOCl + EDTA+ 1,064 nm Nd:YAG laser), and GV (NaOCl + EDTA+ 2,780 nm Er, Cr:YSGG laser). Lasers were applied for 20 s and samples were bisected, exposing the treated surface and then subjected to elements quantification by EDS and morphological evaluation by scanning electron microscope (SEM). EDS data were submitted to ANOVA-two way, and SEM scores were submitted to two-way Kruskal-Wallis and Dunn's tests. The EDS analysis showed no difference for the chemical elements and Ca/P ratio between groups (p > .05). Statistical analysis showed more intense results for GV and less intense results for GI (p < .05). The GIII showed an amorphous organic matrix surface, while GV provided greater removal of intertubular dentin forming craters, and GIV promoted dentin fusion. The EDS method used in this study was not able to verify any chemical changes in root canal dentin; Nd:YAG, Er, Cr:YSGG, and 980 nm diode laser were capable of modifying the dentin morphology, correlating characteristics features for each one, which are essential clinical knowledge to establish the correct indication for each case. RESEARCH HIGHLIGHTS: EDS was not able to verify any chemical changes in root canal dentin after 980 nm diode, Nd:YAG and Er;Cr:YSGG laser treatments Nd:YAG, Er, Cr:YSGG, and 980 nm diode laser modified dentin morphology, correlating characteristics features for each one.

Asunto(s)

RESUMEN

Objective: to verify the accuracy of cone beam computedtomography (CBCT) for measuring dentin thicknessin the danger zone of mandibular molars in order to validatethis method to be used as a clinical auxiliary. Materialsand method: dentin thickness of the distal wall ofmesial canals was measured at 2 mm of furcation areain ten mandibular molars before and after preparation ofcervical and middle thirds. CBCT (0.25 mm voxel size)and stereomicroscopy images were acquired twice foreach sample. CBCT axial images and stereomicroscopeimages were evaluated by a calibrated examiner. Statisticalanalysis was performed using Mann-Whitney testin order to investigate whether CBCT images providedtrusted values. Results: mean values of initial (1.23 versus1.24 mm) and final measurements (0.88 versus 0.87mm) obtained with, respectively, CBCT and stereomicroscopemethods did not show statistical differences(P > 0.5). Conclusion: CBCT images provide high accuracyfor measuring dentin thickness in the danger zoneof mandibular molars. (AU)

Objetivo: avaliar a acurácia da tomografia computadorizada de feixe cônico (TCFC) para mensurar a espessura dentinária na zona de risco de molares inferiores e validar este método, a fim de usá-lo como um auxiliar clínico. Materiais e método: a espessura dentinária da parede distal dos canais mesiais foi medida a 2 mm da área de furca em dez molares inferiores, antes e após a preparação dos terços médio e cervical. Foram adquiridas imagens por TCFC (tamanho do voxel de 0,25 mm) e estereomicroscopia. Um examinador treinado e calibrado avaliou as tomografias no plano axial e as imagens de estereomicroscopia. A análise estatística foi realizada com o teste Mann-Whitney, para verificar se as imagens tomográficas forneceram valores comparáveis à estereomicroscopia. Resultados: a média dos valores obtidos, respectivamente, após as mensurações iniciais (1,23 versus 1,24 mm) e finais (0,88 versus 0,87 mm) das imagens de TCFC e estereomicroscopia não mostraram diferença estatisticamente significativa entre os métodos (P > 0,5). Conclusão: a TCFC produz imagens acuradas para a mensuração da espessura dentinária na zona de risco de molares inferiores. (AU)

Asunto(s)

RESUMEN

This study investigated the effect of application of non-thermal atmospheric plasma (NTAP) on the topography and composition of the dentin surface, as well as the microtensile bond strength (µTBS) of a universal adhesive to NTAP-treated dentin. Exposed flat dentin surfaces from human third molars were either treated with NTAP for 10 and 30 s or untreated (control). The dentin-surface topography and chemical composition were characterized by atomic force microscopy (n = 3) and Raman confocal spectroscopy (n = 5), respectively. The µTBS (n = 8) of Scotchbond Universal to dentin was determined after storage for 24 h and 1 yr, either by direct water exposure or under simulated pulpal pressure. In-situ zymography was used to evaluate the influence of NTAP on the dentin-enzymatic activity. Non-thermal atmospheric plasma produced no remarkable topographical or chemical alterations at the dentin surface; only the amount of phosphate decreased following 10 s of treatment with NTAP. After 1 yr of direct water exposure, the µTBS of NTAP-treated specimens did not differ statistically significantly from that of untreated controls, whereas simulated pulpal pressure-aging resulted in a significantly higher µTBS for NTAP-treated dentin. The dentin-enzymatic activity appeared to be treatment-dependent, but the untreated controls showed more intense fluorescence within the hybrid layer. Scotchbond Universal maintained its µTBS strength after 1 yr of direct water exposure and simulated pulpal pressure, although remarkable statistical differences between treatments were observed depending on the aging condition.

Asunto(s)

RESUMEN

INTRODUCTION: This study compared the shaping ability of ProTaper Next (Dentsply Sirona, Tulsa, OK) and BT-RaCe (FKG Dentaire, La Chaux-de-Fonds, Switzerland) instrument systems in the mesial canals of mandibular molars using micro-computed tomographic (micro-CT) imaging. METHODS: A total of 17 type IV mesial roots of extracted first mandibular molars were scanned using micro-CT imaging before and after root canal preparation with the 2 instrument systems. Both systems were used in the same root but alternating the mesial canals from root to root. The following parameters were analyzed: root canal volume, surface area, unprepared surface areas, transportation, canal/root width ratio, and preparation time. RESULTS: There were no statistically significant differences between the 2 systems for all evaluated parameters (P > .05). The unprepared surface areas for the full canal length and the apical 5-mm segment were 33% and 14% for BT-RaCe and 31% and 14% for ProTaper Next, respectively. After preparation, all root canals had a diameter that was not larger than 35% of the root diameter at the coronal and middle segments. CONCLUSIONS: The 2 systems showed no differences in any of the evaluated shaping parameters. None of the tested systems put the roots at risk of fracture because of excessive dentin removal.

Asunto(s)

RESUMEN

La estimación de la edad cronológica en el estudio de restos humanos esuna tarea esencial para llegar a conclusiones más objetivas respecto a la persona estudiada, la precisión en el cálculo de este dato es un componentefundamental en estudios en contextos antropológicos y forenses. Una alternativa es la que se basa en la medición de la transparencia dela dentina radicular de los dientes permanentes. En el presente estudiose pone a prueba una técnica de estimación de la edad basada en lamedición de la transparencia radicular de dientes procedentes de unacolección esquelética de edad conocida. Los dientes incluidos en este estudiofueron unirradiculares, de la segunda dentición y completos en su estructura. Fueron recolectados de restos esqueletizados desenterrados de un cementerio contemporáneo del poblado de Caltimacán, Hidalgo. Los dientes fueron preparados para favorecer el paso de un haz de luz incandescente a través de su raíz. La medición de la transparencia se llevó a cabo con un calibrador digital con precisión de lectura de centésimas de milímetro. Resultados: El coeficiente de correlación entre la edad conocida y la edad estimada con base en la tabla de predicción de Bang y Ramm (1970) es alto, mostrando un índice de 0.75. En este estudio la diferencia media en años de la estimación que representaun parámetro importante para establecer la efectividad de una técnicafue de −3.06, lo que significa que las predicciones subestiman la edadreal. Conclusiones: El empleo de la transparencia radicular muestrabondad en la estimación, aunada a la sencillez en la observación, aunqueimplica necesariamente la disposición de dientes fuera de su alveolo

Asunto(s)

RESUMEN

OBJECTIVE: This study aimed to evaluate the influence of the NiTi wire in Conventional NiTi (ProTaper Universal PTU) and Controlled Memory NiTi (ProTaper Gold PTG) instrument systems on the quality of root canal preparation. MATERIAL AND METHODS: Twelve mandibular molars with separate mesial canals were scanned using a high-definition microcomputed tomography system. The PTU and PTG instruments were used to shape twelve mesial canals each. The canals were scanned after preparation with F2 and F3 instruments of the PTU and PTG systems. The analyzed parameters included the remaining dentin thickness at the apical and cervical levels, root canal volume and untouched canal walls. Data was analyzed for statistical significance by the Friedman and Dunn's tests. For the comparison of data between groups, the Mann-Whitney test was used. RESULTS: In the pre-operative analysis, there were no statistically significant differences between the groups in terms of the area and volume of root canals (P>.05). There was also no statistically significant difference between the systems with respect to root canal volume after use of the F2 and F3 instruments. There was no statistical difference in the dentin thickness at the first apical level between, before and after instrumentation for both systems. At the 3 cervical levels, the PTG maintained centralization of the preparation on the transition between the F2 and F3 instruments, which did not occur with the PTU. Conclusion The Conventional NiTi (PTU) and Controlled Memory NiTi (PTG) instruments displayed comparable capabilities for shaping the straight mesial root canals of mandibular molars, although the PTG was better than the PTU at maintaining the centralization of the shape in the cervical portion.

Asunto(s)

RESUMEN

Abstract Objective This study aimed to evaluate the influence of the NiTi wire in Conventional NiTi (ProTaper Universal PTU) and Controlled Memory NiTi (ProTaper Gold PTG) instrument systems on the quality of root canal preparation. Material and Methods Twelve mandibular molars with separate mesial canals were scanned using a high-definition microcomputed tomography system. The PTU and PTG instruments were used to shape twelve mesial canals each. The canals were scanned after preparation with F2 and F3 instruments of the PTU and PTG systems. The analyzed parameters included the remaining dentin thickness at the apical and cervical levels, root canal volume and untouched canal walls. Data was analyzed for statistical significance by the Friedman and Dunn’s tests. For the comparison of data between groups, the Mann-Whitney test was used. Results In the pre-operative analysis, there were no statistically significant differences between the groups in terms of the area and volume of root canals (P>.05). There was also no statistically significant difference between the systems with respect to root canal volume after use of the F2 and F3 instruments. There was no statistical difference in the dentin thickness at the first apical level between, before and after instrumentation for both systems. At the 3 cervical levels, the PTG maintained centralization of the preparation on the transition between the F2 and F3 instruments, which did not occur with the PTU. Conclusion The Conventional NiTi (PTU) and Controlled Memory NiTi (PTG) instruments displayed comparable capabilities for shaping the straight mesial root canals of mandibular molars, although the PTG was better than the PTU at maintaining the centralization of the shape in the cervical portion.

Asunto(s)

RESUMEN

A mensuração da degradação de colágeno radicular é um importante parâmetro para avaliar a progressão de cáries na dentina ou a eficácia de métodos terapêuticos na prevenção de lesões não cariosas. O objetivo deste trabalho foi avaliar a degradação do colágeno da dentina radicular frente a métodos de prevenção de cárie, utilizando o teste da Hidroxiprolina e a microradiografia. Foram obtidos 40 blocos de dentina radicular com aproximadamente 1,5 mm de profundidade x 6 mm de diâmetro, a partir de incisivos bovinos, os quais foram submetidos ao processo de desmineralização artificial em tampão acetato (pH=5), a fim de induzir a formação de uma lesão cariosa. Em seguida as amostras foram submetidas aos tratamentos preventivos de cárie radicular: 1) Clorexidina 0,12% 1 min, 2) Flúor neutro 2% 1 min, 3) Nd: YAG Laser- 60 mJ 10 s e 4) Água Deionizada (controle) 1 min. Após os tratamentos as amostras foram expostas à degradação pela enzima colagenase (Tipo VII, Produto No. C0773, Sigma-Aldrich, St. Louis, MO, USA) por um período de 5 dias. Ao final do desafio da colagenase, a solução contendo a enzima foi coletada para ser submetida ao teste da hidroxiprolina, para a mensuração da quantidade de colágeno degradado por meio de colorimetria em espectrofotômetro. Em seguida as mesmas amostras foram submetidas à mais 2 dias de desmineralização. Em complemento ao ensaio da hidroxiprolina as amostras foram expostas à microradiografia transversal para visualização e medição da área degradada. Uma análise descritiva dos dados obtidos foi realizada de modo a determinar o teste estatístico a ser aplicado. A análise de variância (ANOVA) para a HYP revelou que não houve diferença estatisticamente significativa entre os tratamentos empregados (p>0,05). Os dados obtidos na microradiografia foram submetidos ao teste de Kruskal Wallis e teste de comparações múltiplas, Dunn. Os dados de reptetição, comparações entre a desmineralização inicial (5 dias) e a segunda desmineralização (2 dias), foi realizado individulamente em cada grupo por teste T de medidas repetidas ou Wilcoxon. Houve diferença significativa entre os grupos (p<0,0001). Dos tratamentos empregados, a clorexidina e o flúor foram eficazes na prevenção da progressão da cárie radicular(AU)

Quantification of collagen degradation is an important parameter to evaluate dentin caries progression of caries prevention aid. The aim of this study was to evaluate root collagen degradation against preventive methods by using the hydroxyproline assay and microradiography technique. Forty root dentin blocks were obtained with 1,5x6 mm (depth x diameter) from bovine incisors, which were submitted to artificial demineralization process by acetate buffer (PH=5), in order to induce a carious lesion. Then, the samples were submitted to preventive therapeutic treatment of root caries: 1) Chlorhexidine 0,12% 1 min, 2) Fluoride 2% 1 min, 3) Nd:YAG Laser - 60 mJ 10s, 4) Deionized Water (control) 1 min. After that, the samples were exposed to degradation by the collagenase enzyme (Type VII, Product No. C0773, Sigma- Aldrich, St. Louis, MO, USA) for 5 days. Following the collagenase challenge, the enzyme solution was collected for assaying hydroxyproline released from collgen matrix, where it is possilble to measure the amount of degraded collagen by colorimetry in a spectrophotometer. Soon after, the same samples were submitted to a further 2 days of demineralization process. In addition to the hydroxyproline assay the samples were exposed to the transverse microradiography for a visualization of the degraded area. Soon after the colorimetric test the same samples were submitted to further two days of demineralization. A descriptive analysis of the data will be performed to determine the statistical test to be applied. ANOVA test revealed that there was no difference between the treatments (p>0,05). The microradiography data were submitted to the Kruskal Wallis test and multiple comparison test, Dunn. The repetition data, comparisons between the initial (5 days) and the second (2 days) demineralization, were performed individually in each group by repeated measures T-test or Wilcoxon (p<0,0001). Among the proposed treatments, chlorhexidine and fluoride were effective in preventing root caries progression(AU)

Asunto(s)

RESUMEN

The structural changes and morphological derivatives of progressive dentin hypermineralization determine the bonding to its surface. A planimetric study and fracture volume estimate were conducted to assess the efficacy of resin composite bonded to hypermineralized cervical dentin with and without retentions by applying a shear test. Thirty-four premolars from adult patients were used to obtain a flat cervical dentin surface. The specimens were distributed randomly into two groups: 1) experimental, where hemispherical retentions were carved into the cervical dentin, and 2) control, where the flat dentin was maintained. Using a jig, a resin column was built into the dentin surface fitted with bonding in specimens from both groups, which were then subjected to the shear test. The morphological analysis was performed with a microscope while the percentage of remnant surface from each component of the adhesive bond was calculated planimetrically. The volume of lost tissue was determined using Scherle's method. In the planimetric study, the average remnant resin on the surface was significantly higher in the experimental group and there was less intact dentin in the control group. The volumetric assessment also showed a much higher loss of dentin substrate than the experimental group. Consequently, the complementary use of morphometric and volumetric techniques enables the evaluation of the efficacy of a technique, demonstrating that the inclusion of mechanical retentions in hypermineralized cervical dentin improves the bonding properties.

Los cambios estructurales y morfológicos derivados de la hipermineralización dentinaria progresiva determina la adhesión a su superficie. Fue realizado un estudio planimétrico y el volumen de fractura estimado para evaluar la eficacia de resina compuesta adherida a dentina cervical hipermineralizada con y sin retenciones a través de la prueba de cizalla. Treinta y cuatro premolares obtenidos de pacientes adultos fueron utilizados para obtener una superficie dentinaria cervical plana. Las muestras fueron distribuidas aleatoriamente en dos grupos: 1) experimental, donde se realizaron retenciones hemiesféricas a la dentina cervical, y 2) control, donde la dentina plana fue mantenida. Usando un dispositivo, una columna de resina fue construida en la superficie dentinaria y adaptada con adhesivos en las muestras de ambos grupos, las cuales fueron sometidas al test de cizalla. El análisis morfológico fue realizado con un microscopio mientras que el porcentaje de superficie remanente para cada componente del adhesivo fue calculado planimetricamente. El volumen del tejido perdido fue determinado utilizado el método de Scherle. En el estudio planimétrico, el promedio de resina remanente en la superficie fue significativamente mayor en el grupo experimental y con menos dentina intacta en el grupo control. El análisis volumétrico mostró una mayor perdida de sustrato dentinario en el grupo control. De esta manera, el uso de técnicas morfométricas y volumétricas permite la evaluación de la eficacia de una técnica, demostrando que la inclusión de retenciones mecánicas en la dentina hipermineralizada cervical mejora las propiedades de adhesión.

Asunto(s)

RESUMEN

A presente pesquisa se propôs a avaliar a influência de cinco tratamentos dentinários na resistência de união à dentina de quatro cimentos de ionômero de vidro modificados por resina (CIVRMs). O ensaio experimental foi realizado in vitro, fazendo uso de 200 incisivos bovinos. Destes, foram obtidos 200 fragmentos de dentina, que foram distribuídos aleatoriamente em 20 grupos (n=10), segundo os fatores de variação que compreendem cinco tratamentos dentinários (Grupo controle, ou seja, sem tratamento; Ácido Poliacrílico a 20%, Clearfil SE Bond; Single Bond Universal e Primer do Vitremer) e quatro cimentos ionoméricos (GC Fuji II LC® CAPSULE; GC Fuji LINING® LC (Paste Pak); Vitrebond® e Vitremer). Após a confecção dos corpos de prova e 24h de armazenamento em estufa à 37oC, foi realizado o teste de microcisalhamento na máquina de ensaios universal (Instron 5942 - Canton, MA, EUA) com velocidade de 1mm/min, seguido da análise do padrão de fratura em microscópio digital. A análise estatística dos 400 resultados obtidos foi feita por meio do teste paramétrico ANOVA para dois fatores de variação (cimento e tratamento) (p<0,05%) e pelo teste auxiliar de Tukey (p<0,05%). Os testes estatísticos demonstraram haver diferença estatística tanto entre os tratamentos, como entre os cimentos e na interação de ambos (p<0,0001). Os sistemas adesivos Clearfil SE (X?=18,26 ± 2,78) e SingleBond (X?=17,28 ± 2,49) promoveram os valores de resistência adesiva mais elevados em comparação aos demais tratamentos, mas sem apresentarem

diferença estatística entre si, o que representou um aumento na resistência de união de 121% para o Clearfil SE e 109,2% para o Single Bond Universal em relação ao Grupo Controle. O uso do Ácido Poliacrílico (X?=9,94 ± 3,55) alcançou valores intermediários, correspondendo a um aumento de 20% na resistência adesiva em relação ao Grupo Controle. Esse tratamento se diferenciou estatisticamente dos maiores valores, porém não apresentou diferença frente ao Primer do Vitremer (X?=8,91 ± 2,97). O grupo controle (X?=8,26 ± 4,17) evidenciou os menores valores, se diferenciando estatisticamente dos sistemas adesivos e do Ácido Poliacrílico, mas com resultados que o equiparou ao tratamento com o Primer do Vitremer. Ao se analisar a interação entre cimento e tratamento, todos os cimentos de ionômero de vidro resinomodificados (CIVRMs) testados neste estudo apresentaram seus maiores resultados quando um dos sistemas adesivos foi utilizado como tratamento dentinário, independente de qual sistema adesivo. Com base nesses resultados, pôde-se concluir que os dois sistemas adesivos autocondicionantes foram capazes de melhorar significativamente a resistência adesiva dos CIVRMs.

This research aims to evaluate the influence of five dentin pretreatments on microshear bond strength of four resin-modified glass ionomer (RMGI). The experiment was performed in vitro, using 200 bovine incisors. From these, there were obtained 200 dentine fragments that were randomly distributed into 20 groups (n = 10) according to the variation factors comprising five dentin treatment (control group, i.e., no treatment; Polyacrylic Acid 20%; Clearfil SE Bond; Single Bond Universal and Vitremer Primer) and four glass ionomer cements (GC Fuji II LC® CAPSULE; GC Fuji LC LINING® (Paste Pak); Vitrebond® and Vitremer). After preparation of the samples and 24h storage at 37 °C, was performed microshear test in a universal testing machine (Instron 5942 - Canton, MA, USA) with speed of 1mm/min, followed by analysis of the pattern fractures in digital microscope. Statistical analysis of the 400 results was performed by ANOVA nonparametric test for two variation factors (cement and treatment) (p <0.05%) and the post-hoc Tukey (p <0.05%). The tests demonstrated there are statistical difference between treatments, cements and between the interaction of both (p <0.0001). The Clearfil SE (X?=18,26 ± 2,78) and SingleBond (X?=17,28 ± 2,49) promoted the highest bond strength values compared to the other treatments, but showing no statistical difference between them, which represented an increase in bond strength of 121% for

Clearfil SE and 109.2% for Single Bond Universal compared to control group. The Polyacrylic Acid (X?=9,94 ± 3,55) has reached intermediate values, corresponding to a 20% increase in adhesive strength compared to control group. This treatment differed significantly from the higher values, but showed no difference compared to Primer Vitremer (X?=8,91 ± 2,97). The control group (X?=8,26 ± 4,17) showed the lowest values, statistically differing from the adhesives and polyacrylic acid, but with results that matched to the treatment with Vitremer Primer. When analyzing the interaction between cement and treatment, all cements tested in this study had higher results when one of the adhesive systems was used as dentin treatment, regardless of which adhesive system. Based on these results, it could be concluded that the two adhesive systems were able to significantly improve the adhesive strength of RMGIs.

Asunto(s)

RESUMEN

This study aims to describe and analyze morphological and physical properties of deciduous teeth of Sus domesticus. Ultrastructural analysis, mineral composition and microhardness of enamel and dentine tissues were performed on 10 skulls of S. domesticus. External anatomic characteristics and the internal anatomy of the teeth were also described. Data regarding microhardness and ultrastructural analysis were subjected to statistical tests. For ultrastructural analysis, we used the analysis of variance (ANOVA) with Tukey's post hoc (p≤0.05) test. In the analysis of microhardness, the difference between the enamel and dentine tissues was analyzed by a Student's t test. Values were expressed as mean with standard error. The results of ultrastructural analysis showed the presence of an enamel prism pattern. A dentinal tubule pattern was also observed, with a larger diameter in the pulp chamber and the cervical third, in comparison to middle and apical thirds. We observed an average microhardness of 259.2kgf/mm(2) for enamel and 55.17kgf/mm(2) for dentine. In porcine enamel and dentine, the chemical elements Ca and P showed the highest concentration. The analysis of internal anatomy revealed the presence of a simple root canal system and the occurrence of main canals in the roots. The observed features are compatible with the functional demand of these animals, following a pattern very similar to that seen in other groups of mammals, which can encourage the development of research using dental elements from the pig as a substitute for human teeth in laboratory research.

Asunto(s)

RESUMEN

This study aimed to guide the planning of anticurvature filing using pre-determined anatomical points on teeth to establish directions for proper implementation of the technique. Two hundred digital periapical radiographs of human molar teeth were selected and divided into two groups (n = 100): MX (maxillary) and MD (mandibular) molars. Mesiobuccal roots were considered for the MX group and mesial roots for the MD group. Pre-determined anatomical points required for planning the anticurvature filing on the root canal path were located, and the distances between these points obtained. The anticurvature filing was simulated in two different protocols for each group, and the region of dentin removal and the remaining dentin thickness were measured in the safety and danger zones of the root canals. Statistical analysis was carried out at a significance level of 5%. The distances between the anatomical points and the thickness of remaining dentin showed significant differences when the two groups were compared (p < 0.001). No significant differences were found between the two experimental groups regarding the area of dentin removal at the root region, but differences were detected in comparison with dentin removal at the crown (p < 0.001). In terms of wear produced after simulation of both anticurvature filing protocols, significant differences were verified for all regions, except for the dentin remaining at the danger zone. The radiographic location of anatomical points allows for planning and implementation of controlled and efficient anticurvature filing and can be performed in the same manner for maxillary and mandibular molars.

Asunto(s)

RESUMEN

Micro energy-dispersive X-ray fluorescence spectrometry (µ-EDXRF) and scanning electron microscopy (SEM) were used to evaluate dentin treated with an etch and rinse adhesive (ER) and a self-etch adhesive (SE). Ten human molars (H) and ten bovine anterior teeth (B) were prepared (exposure of dentin and divided in the middle) and allocated into two different adhesion strategy groups per substrate (n=40). µ-EDXRF data and SEM images were obtained before and after treatment. Untreated dentin of both substrates did not differ in terms of Ca (p<0.1503), P (p<0.2986) or Ca/P ratio (p<0.1400). H-SE and B-SE specimens showed reduced P content (p<0.0001; p<0.0002), while H-ER and B-ER specimens showed reduced Ca and P content (p<0.0001; p<0.0001) when compared with untreated specimens. The Ca/P ratio was significantly higher in H-ER and B-ER specimens than in H-SE and B-SE specimens (p<0.0001; p<0.0080). Untreated dentin showed a homogeneous elemental distribution. However, after adhesive treatments, the surface of the dentin showed an irregular demineralization pattern. The resin tags and adhesive layer were shorter in bovine specimens than in human specimens due to morphological differences.

Asunto(s)

RESUMEN

Este estudo se propôs a analisar as características morfológicas da dentina humana irradiada com laser de Er:YAG utilizando diferentes larguras temporal de pulso nos protocolos de preparo cavitário e pré-tratamento da dentina. Foram utilizados 18 molares humanos que foram seccionados no sentido mésio-distal e amelocementário obtendo-se um disco plano de dentina. Em seguida foram lixados com uma sequência decrescentes de lixas para padronizar os espécimes em 2mm de espessura. Os grupos experimentais foram compostos a partir de 2 fatores de variação: 1) indicação clínica - preparo cavitário (E=200mJ/20Hz), e pré-tratamento (E=80mJ/2Hz); e 2) largura temporal de pulso - 50, 300 e 600µs. Assim formaram-se 6 grupos experimentais com (n=3): G1(E=200mJ/20Hz/50µs); G2(E=200mJ/20Hz/300µs); G3(E=200mJ/20Hz/600µs); G4(E=80mJ/2Hz/50µs); G5(E=80mJ/2Hz/300µs); G6(E=80mJ/2Hz/600µs). Os espécimes foram irradiados com o laser de Er:YAG com comprimento de onda de 2,94µm, de modo não contato, com um distância de 7mm do feixe de saída, sob irrigação de 60ml/min de água e 40ml/min de ar. Após a irradiação, os espécimes foram processados e destinados à avaliação descritiva das imagens obtidas em Microscopia Eletrônica de Varredura (MEV), nos diferentes grupos experimentais. A análise morfológica dos grupos irradiados revelou uma superfície irregular, ausência de smear layer que expõe a abertura dos túbulos dentinários, dentina peritubular evidente e, sem indícios de carbonização e derretimento para todos os protocolos utilizados

Os resultados deste estudo in vitro mostraram que a irradiação com o laser de Er:YAG promoveram um padrão morfológico microrretentivo característico de ablação para todos os grupos testados e os grupos G1 e G4, que utilizaram a menor largura temporal de pulso (50 µs), apresentaram uma superfície mais rugosa quando comparados aos demais grupos. Por fim, podemos concluir que a largura temporal de pulso influência nas características morfológicas da dentina irradiada nas diferentes indicações clínicas testadas, preparo cavitário e pré-tratamento. A menor largura de pulso (50 µs) produz uma morfologia mais irregular quando comparada as maiores larguras de pulsos (300 e 600 µs)

This study evaluated the morphological characteristics of Er:YAG laser irradiated dentin using different temporal pulses width on the protocols of cavity preparation and dentin pretreatment. Eighteen human molars were cut longitudinally in a mesiodistal direction and amelocemental junction providing dentin disks. Samples were polished in a decreasing silicon carbide paper to obtain standard 2mm thick disks. The experimental groups were divided by two variables: 1) clinical protocol - cavity preparation (E=200mJ/20Hz) and pretreatment (E=80mJ/2Hz); and 2) temporal pulse width - 50, 300 and 600µs. Therefore, six experimental groups were (n=3): G1(E=200mJ/20Hz/50µs); G2(E=200mJ/20Hz/300µs); G3(E=200mJ/20Hz/600µs); G4(E=80mJ/2Hz/50µs); G5(E=80mJ/2Hz/300µs); and G6(E=80mJ/2Hz/600µs). The samples were irradiated with the Er.YAG laser using wave-length of 2.94µm, in a non contact mode at a focal distance of 7mm from the target point under continuous water spray of 60-40ml/min. After the irradiation, the samples were processed and evaluated by scanning electron microscopic evaluation (SEM)

The morphological analysis on the irradiated groups showed an irregular dentin surface, without smear layer, exposed dentinal tubules apertures, evidenced peritubular dentin, without carbonization and melting signs for all groups. A microretentive morphological pattern, characteristic of the ablation process could be observed in all groups. However, groups G1 and G4, that used 50?s of temporal pulse width, presented a greater irregularity when compared to other groups. In conclusion, the temporal pulse width interfere on the morphological characteristic of the irradiated dentin, regardless of clinical protocol, cavity preparation and pretreatment. The shorter the pulse width (50µs), the greater the surface irregularity

Asunto(s)

RESUMEN

This study aimed to guide the planning of anticurvature filing using pre-determined anatomical points on teeth to establish directions for proper implementation of the technique. Two hundred digital periapical radiographs of human molar teeth were selected and divided into two groups (n = 100): MX (maxillary) and MD (mandibular) molars. Mesiobuccal roots were considered for the MX group and mesial roots for the MD group. Pre-determined anatomical points required for planning the anticurvature filing on the root canal path were located, and the distances between these points obtained. The anticurvature filing was simulated in two different protocols for each group, and the region of dentin removal and the remaining dentin thickness were measured in the safety and danger zones of the root canals. Statistical analysis was carried out at a significance level of 5%. The distances between the anatomical points and the thickness of remaining dentin showed significant differences when the two groups were compared (p < 0.001). No significant differences were found between the two experimental groups regarding the area of dentin removal at the root region, but differences were detected in comparison with dentin removal at the crown (p < 0.001). In terms of wear produced after simulation of both anticurvature filing protocols, significant differences were verified for all regions, except for the dentin remaining at the danger zone. The radiographic location of anatomical points allows for planning and implementation of controlled and efficient anticurvature filing and can be performed in the same manner for maxillary and mandibular molars.

Asunto(s)

RESUMEN

En una investigación forense existen diversas incógnitas médico legales y criminalísticas por definir: especie, sexo, edad, identidad, causa y data de muerte de la víctima o victimario. Fenómenos biológicos han colaborado en estimar la edad médico legal de un individuo. Investigadores han propuesto diferentes métodos para esta estimación. El fenómeno de la translucidez dentinaria radicular se asocia con el aumento de la edad del individuo y ha demostrado ser de gran utilidad en esta estimación. El objetivo fue comparar el acierto en la estimación de la edad médico legal en tres rangos etarios predeterminados, mediante la medición de la translucidez dentinaria radicular, aplicando dos metodologías. Se realizaron mediciones de la longitud de la translucidez de piezas dentarias de una población chilena (n=94), mediante un método visual directo convencional y un método digital indirecto basado en una captura computarizada de la imagen. Se estimó la edad aplicando una tabla propuesta. Se preestablecieron tres rangos de edad: 1er rango (20-39 años), 2do rango (40­59 años) y 3er rango (60­79 años). El método digital muestra un acierto en la estimación de la edad en el 1er rango etario (93%), en comparación al método visual que muestra un acierto 2do y 3er rango (86% y 65%). Existen diferencias significativas p=0,001 entre ambos métodos para cada rango. La diferencia no es estadísticamente significativa en los porcentajes totales de aciertos en la estimación de la edad con ambos métodos. Enfrentados a la estimación de la edad en piezas dentarias con poca TDR se recomienda el método digital, considerando que tiende a una subestimación. En casos de mayor TDR recomendamos el método visual, que tiende a sobreestimar. Este trabajo demuestra que ambos métodos son igualmente efectivos.

In a forensic investigation there are several forensic and criminology unknowns to be elucidated, such as, species, sex, age, identity, cause and date of death of the victim or perpetrator. Some biological phenomena have been used to collaborate in determining the forensic age of an individual. Many authors and researchers have proposed different ways to perform this estimate. The phenomenon of root dentine translucency (RDT) is associated with the increase of age of the individual and has proven to be useful in the estimation of this unknown. The objective of this study was to compare the accuracy in estimating forensic age in three age ranges, by measurement of RDT, using two different methodologies. The protocol consists of taking measurements of the length translucency of dental pieces in a Chilean population (n=94), by direct visual method conventionally used and an indirect digital method based on the capture of a computerized image. The age was estimated applying a table: Three age ranges are preset: 1st range (20-39 ages), 2nd range (40-59 ages) and 3rd range (60-79 ages). The digital method gave better results in the estimation of age in the 1st age range (93%), compared to the visual method that was more assertive in the 2nd and 3rd range (86% and 65%). There are significant differences p=0.001 between the methods for each age range. The difference between the total percentages of successes in the age estimate obtained with both methods are not statistically significant. In conclusion, for age determination in teeth with very little translucency the digital method is recommended, although we must consider that this method tends to underestimate age. In cases of higher RDT we recommend using the visual method; however this method tends to overestimate age. Regardless of the above conclusion, this work shows that both methods are equally effective.

Asunto(s)