RESUMEN
INTRODUCTION: The success of endodontic treatment depends on the significant disinfection of the root canal system, its irregularities, and dentinal tubules. However, achieving complete disinfection remains challenging, with frequent failures and occurrence of secondary infections. Here, we propose using iontophoresis to increase the penetration and distribution of disinfecting agents into root canals, using methylene blue for proof-of-concept. METHODS: The marker was applied in bovine root canals, and the radial distribution of the dye in the dentinal tubules was evaluated by optical microscopy. Iontophoresis was applied at 0.5 and 1.5 mA for 5 and 15 min. RESULTS: A significant statistical difference (p < 0.05) was observed in the marker penetration between passive and iontophoretic applications. Both current density and application time had an important effect on methylene blue distribution, with a greater efficacy delivery to the apical region achieved after 1.5 mA for 5 min or 0.5 mA for 15 min, showing longer application time can compensate for lower application current. CONCLUSION: Iontophoresis increases the penetration and distribution of methylene blue into bovine root canals and dentinal tubules, including its innermost portions. CLINICAL SIGNIFICANCE: Iontophoresis has shown to be a promising technique for root canal and dentinal tubule disinfection.
Asunto(s)
Dentina , Iontoforesis , Animales , Bovinos , Preparaciones Farmacéuticas , Cavidad Pulpar , Azul de Metileno/farmacología , Preparación del Conducto Radicular/métodos , Irrigantes del Conducto Radicular/farmacologíaRESUMEN
Abstract This study assessed the intratubular antibacterial ability of different activated irrigations after chemical mechanical preparation. Seventy-two palatal root canals of upper molars were infected with Enterococcus faecalis for 4 weeks, and then initial bacterial collection from the main root canal was performed. The root canals were prepared by using a WaveOne Gold large (45/.05) and distributed into 6 groups according to the activation of the final irrigation: ultrasonic activation (UA), XP-Endo Finisher (25/.00), XP Clean (25/.02), EasyClean (25/.04) in reciprocating motion and continuous rotary motion (ECRot), and conventional irrigation. After final irrigation, another bacterial collection from the main root canal was performed, and the root was sectioned transversely in three-thirds and stained for analysis by confocal laser microscopy. Intratubular bacteria were collected through dentin powder and plated for bacterial viability analysis. Intergroup and intragroup comparisons were performed by using analysis of variance and repeated measures analysis of variance, respectively, both at 5% significance. ECRot had higher antibacterial ability than UA (p<0.05), and both were superior to the other groups (p<0.05) in both methodologies. It can be concluded that activation of final irrigation enhances the disinfection of the root canal system, and activators have different efficacies
Resumo Este estudo avaliou a capacidade antibacteriana intratubular de diferentes irrigações ativadas após o preparo químico-mecânico. Setenta e dois canais palatinos de molares superiores foram contaminados com Enterococcus faecalis por 4 semanas, e então a coleta bacteriana inicial do canal principal foi realizada. Os canais foram preparados com WaveOne Gold large (45/.05) e distribuídos em 6 grupos de acordo com a ativação da irrigação final: ativação ultrassônica (UA), XP-Endo Finisher (25/.00), XP Clean (25/.02), EasyClean (25/.04) em movimento reciprocante e em movimento rotatório contínuo (ECRot) e irrigação convencional. Após a irrigação final, outra coleta bacteriana do canal principal foi realizada, e a raiz foi seccionada transversalmente em três terços e corada para análise por microscopia laser confocal. Bactérias intra tubulares foram coletadas através de pó de dentina e cultivadas para análise de viabilidade bacteriana. As comparações entre grupos e intragrupos foram realizadas usando análise de variância e análise de variância de medidas repetidas, respectivamente, ambas com 5% de significância. ECRot apresentou maior capacidade antibacteriana que UA (p<0,05), e ambos foram superiores aos demais grupos (p<0,05) em ambas as metodologias. Pode-se concluir que a ativação da irrigação final melhora a desinfecção do sistema de canais radiculares, e os ativadores têm eficácias diferentes.
RESUMEN
Abstract ER:YAG laser and experimental resin-based dental adhesive loaded with functionalized carbonated apatite filler were used in this study to evaluate the dentin interaction in terms of penetration and occlusion of the dentinal tubules aiding in the control of dentin hypersensitivity (DH). Spheroidal Carbonated apatite nanoparticles (N-CAP), with an average size of 20±5 nm diameter, were synthesized, characterized, and incorporated in a universal adhesive "All Bond Universal, Bisco, USA", in (2% weight) concentration. Er:YAG laser "Lightwalker, FOTONA, EU" was adjusted to an energy output of 40mJ/ pulse and pulse repetition of 10 Hz for 10 seconds. Dentin specimens were prepared from the buccal surface of 75 extracted sound human molars. The specimens were randomly divided into five groups (n=15) according to the surface treatment: Group (L): Laser only; Group (LB): Laser in combination with adhesive; Group (LBN): Laser in combination with adhesive loaded with N-CAP; Group (B): adhesive only; and Group (BN): adhesive loaded with N-CAP. Depth of penetration and occlusion of the dentinal tubules were assessed using Environmental Scanning Electron Microscope Examination (ESEM). One-way ANOVA was used to compare groups, followed by a pairwise test for multiple comparisons (α=0.05). Groups (LB), and (LBN) showed the highest mean of dentinal tubules' penetration, with a non-significant difference between them. In contrast, the specimens treated with laser only (L) showed the most minor penetration. The employment of ER-YAG laser irradiation with the adhesive loaded with N-CAP was evaluated to be effective in penetrating and occluding the opened dentinal tubules.
Resumo O laser ER-YAG e o adesivo dentário experimental à base de resina carregado com carga de apatita carbonatada funcionalizada foram usados neste estudo para avaliar a interação com a dentina em termos de penetração e oclusão dos túbulos dentinários, auxiliando no controle da hipersensibilidade dentinária (HD). Nanopartículas de apatita carbonatada esferoidal (N-CAP), com tamanho médio de 20±5 nm de diâmetro, foram sintetizadas, caracterizadas e incorporadas em um adesivo universal "All Bond Universal, Bisco, EUA", na concentração de 2% em peso. O laser Er:YAG "Lightwalker, FOTONA, EU" foi ajustado para uma saída de energia de 40mJ/pulso e repetição de pulso de 10 Hz por 10 segundos. Os espécimes de dentina foram preparados a partir da superfície vestibular de 75 molares humanos sadios extraídos. Os espécimes foram divididos aleatoriamente em cinco grupos (n=15) de acordo com o tratamento da superfície: Grupo (L): Somente laser; Grupo (LB): Laser em combinação com adesivo; Grupo (LBN): Laser em combinação com adesivo carregado com N-CAP; Grupo (B): somente adesivo; e Grupo (BN): adesivo carregado com N-CAP. A profundidade de penetração e a oclusão dos túbulos dentinários foram avaliadas por meio do Exame de Microscópio Eletrônico de Varredura Ambiental (ESEM). ANOVA de um fator foi usada para comparar os grupos, seguida pelo teste de pares para comparações múltiplas (α=0,05). Os grupos (LB) e (LBN) apresentaram a maior média de penetração dos túbulos dentinários, com uma diferença não significativa entre eles. Em contraste, os espécimes tratados apenas com laser (L) apresentaram menor penetração. O emprego da irradiação do laser ER-YAG com o adesivo carregado com N-CAP foi avaliado como eficaz na penetração e oclusão dos túbulos dentinários abertos.
RESUMEN
Abstract Aiming to kill bacteria in dentin tubules of infected dental pulp cavities, we evaluated the effects of sodium hypochlorite (NaOCl) solution agitated by different irrigation protocols, i.e., conventional needle irrigation (CNI), passive ultrasonic irrigation (PUI), the EDDY tip, and the neodymium-doped yttrium aluminum perovskite (Nd:YAP) laser. The EDDY achieved good antibacterial effects as passive ultrasonic irrigation in the coronal and middle thirds. Nd:YAP laser irradiation and PUI were effective in the apical third of the root canal. Objectives: To evaluate the ability of NaOCl agitated by high-frequency sonic irrigation-EDDY, PUI, and Nd:YAP laser-to kill bacteria in infected root canal walls and if the associated temperature increases at the root surface during application. Methodology: Infected root canal models were established, and roots were randomly divided into six groups: negative control, positive control, CNI, PUI, sonic agitation with EDDY, and Nd:YAP laser groups. After irrigation, the teeth were split and stained using the LIVE/DEAD BacLight Bacterial Viability Kit. Dead bacteria depth was evaluated by a confocal laser scanning microscopy and the temperature at the root surface was assessed using a thermal imaging camera during the irrigation process. Results: In the coronal and middle thirds of the root canal, PUI and EDDY had stronger antibacterial effects than CNI (p<0.05); in the apical third, the antibacterial effects of PUI and Nd:YAP laser-activated irrigation were better than CNI (p<0.05). The maximum change in temperature was significantly greater during continuous Nd:YAP laser application compared with the other methods, but intermittent irrigation helped lessening this trend. Conclusions: NaOCl agitated by EDDY tip and PUI exhibited a similar bacteria elimination effect in the coronal and middle root canal. Nd:YAP laser was effective in the apical third and intermittent irrigation reduced its thermal impact.
RESUMEN
La dentina se compone de un mineral de fosfato de calcio identificado como dahllita, que se dispone en pequeños cristales de hidroxiapatita carbonatada con dimensiones de 36 × 25 × 4 nm, y por una fase orgánica cuyo principal componente es el colágeno tipo 1 en 90%, que se orienta en forma de malla. Esta conformación corresponde a los dientes permanentes. Dentro de las estructuras, encontramos túbulos dentinarios que miden, aproximadamente, entre 0.5-1 µm de diámetro en la periferia y hasta 3-5 µm cerca de la pulpa. En el presente estudio, realizado en dentina de dientes temporales, el lumen de dichos túbulos es más grande cuando se encuentra cerca de la pulpa dental. Asimismo, se encontraron cambios elementales importantes de acuerdo con las diferentes profundidades en las que se observó, encontrando un aumento en el peso porcentual de carbono cuando se encuentra a mayor profundidad, lo que indica una composición orgánica mayor en la dentina pulpar. En estudios de dientes permanentes esta composición es disminuida y con mayor concentración en la dentina cercana a la unión amelodentinaria. En dentina de dientes temporales se encontraron diferencias en el recuento de túbulos dentinarios por mm2, comparado a la dentina de dientes permanentes, donde el número de túbulos no varía mucho (AU)
Dentin is composed of a calcium phosphate mineral identified as dahllite, which is arranged in small crystals of carbonated hydroxyapatite with dimensions of 36 × 25 × 4 nm, and by an organic phase whose main component is type l collagen in 90%, which is oriented in the form of a mesh. This conformation corresponds to permanent teeth. Within the structures, we find dentin tubules that measure approximately 0.5-1 µm in diameter at the periphery and up to 3-5 µm near the pulp. In the present study, carried out in dentin of primary teeth, the lumen of these tubules is larger when it is close to the dental pulp. Likewise, important elemental changes were found according to the different depths in which it was observed, finding an increase in the percentage weight of carbon when it is at a greater depth, indicating a greater organic composition in the pulp dentin. In studies of permanent teeth, this composition is decreased and with a higher concentration in the dentin near the amelodentinal junction. In dentin of primary teeth, differences were found in the count of dentin tubules per mm2, compared to dentin of permanent teeth, where the number of tubules did not vary much (AU)
Asunto(s)
Humanos , Diente Primario , Dentina/ultraestructura , Dentinogénesis , Fosfatos , Ácidos Fosfóricos , Grabado Ácido Dental , Microscopía Electrónica de Rastreo , Calcio , Colágeno , Durapatita , Dentición Permanente , Colágeno Tipo I , MineralesRESUMEN
Diferentes estudios han demostrado que después de la tercera década de vida hay una transición en la microestructura de la dentina. Dada la importancia de ésta como sustrato para la adhesión de materiales de restauración utilizados en operatoria y rehabilitación oral, ha sido objetivo de este trabajo realizar una búsqueda bibliográfica de las publicaciones existentes en inglés y español de los últimos 15 años, haciendo uso de buscadores científicos como Pubmed, Google Schoolar y LILACS que permitieran actualizar la información existente ayudando a entender los efectos biológicos del envejecimiento de la dentina, identificando los cambios de mayor relevancia a nivel histológico. De la búsqueda realizada se concluye que el envejecimiento de la dentina está asociado con aumento de dentina secundaria, formación de dentina esclerótica opaca, variaciones en la composición química de la matriz y disminución del número y actividad de los odontoblastos. Los conocimientos sobre el envejecimiento de la dentina deben tenerse en cuenta frente a estudios relacionados con materiales de restauración dental, ya que los cambios en la microestructura y capacidad funcional de la dentina con el envejecimiento requieren que éstos se adapten a dichas variaciones (AU)
Different studies have shown that aafter the third term of life there is a transition in the microstructure of dentin. Given the importance of dentin as a substrate for the adhesion of restorative materials used in operative and oral rehabilitation, the aim of the present work was to conduct a search of the scientific literature in English and Spanish, published in the last 15 years, using search engines such as Pubmed, Google Schoolar and LILACS, for an update on the biological effects of dentin aging, to identify the most relevant age-related histological changes in dentina. The data obtained from the literature review allow concluding that dentin aging is associated with an increase in secondary dentina, opaque sclerotic dentin formation, variations in the chemical composition of the matrix and a decrease in odontoblast number and activity. Updated information on dentin aging should be taken into account in studies on dental restoration materials, since the latter must adapt to aging-related changes in the microstructure and functional capacity of dentin (AU)
Asunto(s)
Humanos , Envejecimiento/fisiología , Dentina/fisiopatología , Odontoblastos , Recubrimientos Dentinarios , Materiales Dentales , Restauración Dental Permanente , DentinogénesisRESUMEN
La exposición de dentina radicular asociada a una recesión gingival puede producir dolor ante distintos estímulos, situación que puede difi cultar la vida cotidiana de los pacientes que lo padecen, además de presentar complicaciones estéticas que pueden afectar la autoestima. La hipersensibilidad dentinaria tiene una etiología asociada a múltiples factores, siendo el principal factor de riesgo la recesión gingival, situación clínica común que se observa en gran parte de la población. El propósito de esta revisión es reunir distintos conceptos que expliquen la asociación que mantienen estas dos patologías, sus etiologías, el cuadro clínico que presenta la hipersensibilidad dentinaria para poder realizar un diagnóstico diferencial y las distintas opciones de tratamiento para realizar un adecuado manejo de esta condición que incluyen desde recursos terapéuticos que buscan resolver la sintomatología hasta procedimientos quirúrgicos que resultan más invasivos y que se enfocan en tratar el factor predisponente como es la recesión gingival misma (AU)
Dentin exposure level periodontal tissues can cause pain to diff erent stimuli, a situation which can hinder the daily lives of patients who suff er, in addition to having aesthetic complications that can damage self-esteem. Dental hypersensitivity has a multifactorial etiology associated being the main risk factor gingival recession, the common clinical situation observed in much of the population. The purpose of this review is to bring together various concepts that explain the association that maintain these two pathologies, their etiologies, clinical picture presented dentine hypersensitivity to perform a diff erential diagnosis and treatment options for proper management of this condition ranging from therapeutic procedure seeking to resolve the symptoms to surgical procedures that are more invasive and that focus on treating the predisposing factor such as the gingival recession itself (AU)
Asunto(s)
Humanos , Sensibilidad de la Dentina/diagnóstico , Sensibilidad de la Dentina/etiología , Sensibilidad de la Dentina/terapia , Recesión Gingival/complicaciones , Compuestos de Potasio , Diagnóstico Diferencial , Terapia por Láser , Recesión Gingival/clasificaciónRESUMEN
AIM: To evaluate the effects of the [NaF 12 g L-1 + NaCl 1 g L-1 ] solution used in the electrochemical dissolution process of fractured endodontic files, as well as its NiTi-containing product, on dentine hardness, topography and human fibroblast viability. METHODOLOGY: Sixty single-rooted human teeth were evaluated for dentine microhardness using the Vickers hardness test and the area and number of dentinal tubules by scanning electron microscopy. The samples were divided according to the dentine surface treatment: distilled water; 17% EDTA; [NaF 12 g L-1 + NaCl 1 g L-1 ]; and 17% EDTA + [NaF 12 g L-1 + NaCl 1 g L-1 ]. Thirty-six single-rooted human teeth were divided according to the irrigation protocol: Dulbecco's Modified Eagle's Medium + 10% foetal bovine serum; 5.25% NaOCl; [NaF 12 g L-1 + NaCl 1 g L-1 ]; and [NaF 12 g L-1 + NaCl 1 g L-1 + NiTi]. The extracts in contact with the apical foramen were used in the MTT assay to evaluate human fibroblast viability, with dilutions of 100%, 50%, 25% and 12.5%. Statistical tests used were paired t-tests, one-way anova, Tukey's test, Kruskal-Wallis test and Dunn's post-test. RESULTS: The [NaF 12 g L-1 + NaCl 1 g L-1 ] solution did not modify dentine microhardness or the average dentinal tubule area. However, EDTA induced changes in dentine structure and microhardness (P < 0.05). The [NaF 12 g L-1 + NaCl 1 g L-1 ] solution, and its NiTi-containing product had lower cytotoxicity than NaOCl at dilutions of 25% and 50% (P < 0.01). CONCLUSIONS: The [NaF 12 g L-1 + NaCl 1 g L-1 ] solution did not alter dentine microhardness or damage the dentine structure. It also demonstrated lower cytotoxicity than NaOCl.
Asunto(s)
Dentina/efectos de los fármacos , Dentina/patología , Técnicas Electroquímicas , Níquel/toxicidad , Preparación del Conducto Radicular/instrumentación , Titanio/toxicidad , Adolescente , Técnicas de Cultivo de Célula , Línea Celular , Supervivencia Celular/efectos de los fármacos , Niño , Preescolar , Electrólisis , Falla de Equipo , Fibroblastos/efectos de los fármacos , Dureza , Humanos , Lactante , Microscopía Electrónica de Rastreo , Níquel/química , Piel , Cloruro de Sodio/farmacología , Fluoruro de Sodio/farmacología , Hipoclorito de Sodio/farmacología , Solubilidad , Factores de Tiempo , Titanio/químicaRESUMEN
Antecedentes: uno de los objetivos del tratamiento endodónticoconsiste en lograr la eliminación de los microorganismos residentes enlos conductos radiculares. Sin embargo, los microorganismos presentesen la necrosis pulpar se adaptan a las condiciones de los conductosnecróticos penetrando en los túbulos dentinarios, lo que complica elpronóstico del tratamiento. Objetivo: El propósito de esta investigaciónfue describir histológicamente las zonas de formación y distribución dela biopelícula tanto en los conductos como en los túbulos dentinarios dedientes extraídos con patología pulpo-periapical. Material y métodos:Se estudiaron 34 muestras de dientes extraídos con lesiones periapicales.Ninguno de los especímenes tenía tratamiento de conductos previo, nilesión endoperiodontal, ni fractura longitudinal o fractura de la raíz.Los dientes fueron descalcifi cados en ácido fórmico al 5% en formolamortiguado durante siete semanas. Se realizó el procedimiento histoló-gico de rutina para inclusión de las muestras en parafi na. Se obtuvieroncortes seriados longitudinales del conducto pulpar para someterlos atinción con hematoxilina y eosina, tinción de ácido peryódico de Schiff ,metenamina de plata y de Gram & Taylor Brown-Brenn para identifi carlos túbulos dentinarios, la presencia de hongos y bacterias. Resultados:De los 544 cortes estudiados, 75% (405) tuvieron colonizaciónmicrobiana. No se encontraron evidencias de la presencia de hongos.Con respecto a la profundidad de penetración de los microorganismosen los túbulos se identifi caron 194 cortes (35.6%) con presencia debacterias en 150 μm y 211 muestras (38.7%) en los que la penetraciónfue más allá de 500 μm...
Background: one of the main goals of endodontic treatment is toachieve the elimination of resident microorganisms in the root canal.However, the microorganisms involved in the pulp necrosis adapt to theconditions of necrotic canals, penetrating the dentinal tubules, whichcomplicates treatment. Objective: The purpose of this research was tohistologically describe the areas of formation and distribution of biofi lmin both the canals and the dentinal tubules of teeth extracted with pulpand periapical pathology. Material and methods: 34 samples of teethwith periapical lesions were studied. None of the specimens had priorcanal treatment, endoperiodontal injury, fracture nor longitudinal rootfracture. Teeth were decalcifi ed with 5% formic acid and buff ered withformalin for 7 weeks. Histological routine procedure for includingsamples in paraffi n was conducted. Longitudinal serial sections wereobtained of the pulp canal space for submission to staining withhematoxylin and eosin, peryodic acid Schiff , methenamine silver, andGram & Taylor Brown-Brenn, to identify dentinal tubules and thepresence of fungi and bacteria. Results: Of the 544 histological sectionsunder study 75% (405) showed microbial colonization. No evidence offungi was found. 194 histological sections (35.6%) had microorganismspenetrating the dentinal tubules to a depth of 150 microns, and 211histological sections (38.7%) had microorganisms penetrating thedentinal tubules for more than 500 μm...
Asunto(s)
Humanos , Cavidad Pulpar/anatomía & histología , Cavidad Pulpar/microbiología , Dentina/microbiología , Necrosis de la Pulpa Dental/epidemiología , Necrosis de la Pulpa Dental/microbiología , Epidemiología Descriptiva , Técnicas Histológicas , México , Placa Dental/microbiología , Interpretación Estadística de DatosRESUMEN
Objetivo: avaliar o número de aplicações necessárias para a completa obliteração dos túbulos dentinários utilizando diferentes agentes dessensibilizantes. Material e Métodos: a porção do esmalte coronário da face vestibular de 40 incisivos bovinos foi removida com auxílio de lixas para expor a dentina superficial da junção amelo-cementária. Em seguida, as raízes e a porção coronária referente ao terço médio-incisal dos dentes foram removidas. A seguir foi realizada a completa remoção de smear layer, evidenciando os túbulos dentinários. As amostras foram divididas em quatro grupos experimentais conforme o agente dessensibilizante utilizado: verniz fluoretado, adesivo dentinário, dessensibilizante dentinário e creme dental. Os produtos foram aplicados de acordo com as recomendações do fabricante. As amostras foram avaliadas previamente e após o uso dos agentes por microscopia eletrônica de varredura de baixo vácuo. A aplicação do agente e a análise foram realizadas até a completa obliteração dos túbulos dentinários. Os dados foram avaliados estatisticamente em relação ao número de aplicações necessárias utilizando os testes de Kruskal-Wallis e Mann-Whitney (p < 0,05). Resultados: o verniz fluoretado foi o mais eficaz dos agentes avaliados, sendo necessária uma aplicação para a completa obliteração dos túbulos. Para o adesivo dentinário foram necessárias duas aplicações e para o dessensibilizante e o creme dental foram necessárias cinco aplicações. Conclusão: os agentes dessensibilizantes testados necessitam de um número variado de aplicações, sendo o mais eficaz o verniz fluoretado, onde apenas uma aplicação possibilitou a completa obliteração dos túbulos.
Objective: The aim of this study was to evaluate the number of applications necessary for the complete obliteration of dentinal tubules using different desensitizing agents. Materials and Methods: A portion of coronary enamel of the buccal surface of 40 bovine incisors was removed with the aid of sandpaper in order to expose the superficial dentin at the dentin-enamel junction. The roots and the coronary portions of the mesial-incisal third of the teeth were also removed. Complete smear-layer removal was performed, exposing the dentinal tubules. Samples were divided into four experimental groups according to the desensitizing agents used: fluoride varnish; dentin adhesive; dentin desensitizing; and toothpaste. The products were applied in accordance with the manufacturer's recommendations. Samples were evaluated before and after the application of different agents by scanning electronic microscopy of low vacuum. The application of the products and analyses were carried out until complete obliteration of dentinal tubules. Data were evaluated statistically in relation to the required number of applications, using Kruskal-Wallis and Mann-Whitney tests (p < 0.05). Results: The results showed that fluoride varnish was the most efficient of the tested agents, requiring a single application for the complete obliteration of the dentinal tubule. For the dentin adhesive, two applications were necessary and for the dentin desensitizing and toothpaste, five applications were required. Conclusion: The desensitizing agents tested required a distinct number of applications, and the fluoride varnish was the most effective agent, with a single application resulting in the complete obliteration of the dentin tubule.
RESUMEN
OBJECTIVE: Understanding the effects of biological aging on human tissues has been a topic of extensive research. With the increase in healthy seniors and quality of life that topic is becoming increasingly important. In this investigation the effects of aging on the microstructure, chemical composition and hardness of human coronal dentin was studied from a comparison of teeth within "young" and "old" age groups. METHODS: The microstructure of dentin within three regions (i.e., inner, middle and outer) was analyzed using electron and optical microscopy. The mineral-to-collagen ratio in these three regions was estimated using Raman spectroscopy and the hardness was evaluated using microindentation. RESULTS: Results showed that there were significant differences in tubule density, tubule diameter and peritubular cuff diameter with depth. Although there was no difference in tubule density and diameter of the tubules between the age groups, there was a significant difference in the occlusion ratio. A significant increase in hardness between young and old patients was found for middle and outer dentin. An increase in mineral-to-collagen ratio from inner to outer dentin was also found for both groups. In old patients, an increase in mineral content was found in outer coronal dentin as a consequence of tubule occlusion. CONCLUSIONS: An increase in occlusion ratio, hardness, and mineral content was found in the dentin of adult patients with age. This increase is most evident in the outer coronal dentin.
Asunto(s)
Envejecimiento , Dentina/química , Dentina/ultraestructura , Adolescente , Adulto , Factores de Edad , Anciano , Femenino , Dureza , Humanos , Técnicas In Vitro , Masculino , Microscopía Electrónica de Rastreo , Persona de Mediana Edad , Tercer Molar , Espectrometría Raman , Propiedades de SuperficieRESUMEN
INTRODUCTION: Pulp biology is central to the whole tooth, and knowledge on its microstructure is changing with new studies. This study presents certain microfibrillar structures found within the dentin tubules of human teeth connecting dentin tubules and odontoblastic processes. METHODS: We analyzed the crowns of 30 noncarious, human teeth. They were fixed; demineralized; and, later, processed and reviewed by means of scanning electron microscopy. RESULTS: In the predentin layer, we found numerous fine fibrillar structures connecting the odontoblastic process and the wall of the dentinal tubule. In the inner dentinal third, we observed structures forming a dense microfibrillar network of variable thickness and diameters. These microstructures were very thin and numerous in this area, and their number decreased as more external dentin levels were examined. CONCLUSIONS: According to the review of the literature and our findings, these microfibrillar structures may be an unrecognized support system that holds and secures the odontoblastic process within the dentinal tubule.
Asunto(s)
Dentina/ultraestructura , Microfibrillas/ultraestructura , Adolescente , Humanos , Microscopía Electrónica de Rastreo , Odontoblastos/ultraestructura , Odontogénesis , Adulto JovenRESUMEN
Introdução: Vários tratamentos são propostos para a hipersensibilidade dentinária sendo consenso que o objetivo principal do tratamento é a obliteração dos túbulos dentinários. Objetivo: Avaliar o número de aplicações necessárias para a completa obliteração dos túbulos dentinários utilizando diferentes agentes dessensibilizantes. Material e Método: A porção do esmalte coronário da face vestibular de 40 incisivos bovinos foi removida com auxílio de lixas para expor a dentina superficial da junção amelo-cementária. Em seguida, as raízes e a porção coronária referente ao terço médio-incisal dos dentes foram removidas. A seguir foi realizada a completa remoção de smear layer, evidenciando os túbulos dentinários. As amostras foram divididas em 4 grupos experimentais conforme o agente dessensibilizante utilizado: verniz fluoretado, adesivo dentinário, dessensibilizante dentinário e creme dental. Os produtos foram aplicados de acordo com as recomendações do fabricante. As amostras foram avaliadas previamente e após o uso dos agentes por microscopia eletrônica de varredura de baixo vácuo. A aplicação do agente e a análise foram realizadas até a completa obliteração dos túbulos dentinários. Os dados foram avaliados estatisticamente em relação ao número de aplicações necessárias utilizando os testes de Kruskal-Wallis e Mann-Whitney (pï¼0,05). Resultado: O verniz fluoretado foi o mais eficaz dos agentes avaliados, sendo necessária uma aplicação para a completa obliteração dos túbulos. Para o adesivo dentinário foram necessárias duas aplicações e para o dessensibilizante e o creme dental foram necessárias cinco aplicações. Conclusão: Os agentes dessensibilizantes testados necessitam de um número variado de aplicações, sendo o mais eficaz o verniz fluoretado, onde apenas uma aplicação possibilitou a completa obliteração dos túbulos. (AU)
Introduction: Several treatments are proposed for dentin sensitivity and the consensus is that the main objective of the treatment is the complete obliteration of the dentinal tubules. Objective: To evaluate the number of applications necessary for the complete obliteration of the dentinal tubules using different desensitizing agents. Material and Methods: a portion of coronary enamel of the buccal surface of 40 bovine incisors was removed with the aid of sandpaper in order to expose the superficial dentin at the dentin-enamel junction. The roots and the coronary portions of the mesial-incisal third of the teeth were also removed. Complete smear layer removal was performed, exposing the dentinal tubules. Samples were divided into 4 experimental groups as desensitizing agents used: fluoride varnish, dentin adhesive, dentin desensitizing and toothpaste. The products were applied in accordance to the manufacturer's recommendation. Samples were evaluated before and after the application of different agents by scanning electronic microscopy of low vacuum. The application the products and analysis was carried out until complete obliteration of dentinal tubules. Data was evaluated statistically in relation to the required number of applications using Kruskal-Wallis and Mann-Whitney (p<0, 05). Results: Fluoride varnish was the most efficient of the tested agents, requiring a single application for the complete dentinal tubule obliteration. For the dentin adhesive, two applications were necessary and for the dentin desensitizing and toothpaste five applications were required. Conclusion: The desensitizing agents tested require distinct number of applications, and the fluoride varnish is the most effective one, which a single application resulted in the complete dentin tubule obliteration. (AU)
Asunto(s)
Animales , Bovinos , Desensibilizantes Dentinarios/farmacología , Recubrimientos Dentinarios/normas , Pastas de Dientes/normas , Desensibilizantes Dentinarios/normas , Incisivo , Microscopía Electrónica de RastreoRESUMEN
La diferenciación mesenquimal a odontoblasto es un proceso complejo que determina la formación de los túbulos dentinales. Este proceso involucra una cuidadosa y regulada secuencia de cambios en el comportamiento de las células mesenquimales, coordinados por la expresión de diferentes factores moleculares, entre ellos, principalmente, el Noggin y BMP2. En este artículo se simula la formación de los túbulos dentinales a partir de un modelo matemático de reacción difusión que es solucionado por el método de los elementos finitos...
Mesenchymal differentiation into odontoblasts is a complex process determining the formation of dentinal tubules. The process involves a carefully regulated sequence of changes in the behavior of mesenchymal cells, coordinated by the expression of various molecular factors, particularly Noggin and BMP2. In this paper the formation of dentinal tubules is simulated using a reaction-diffusion mathematical model solved by the finite element method...
RESUMEN
O presente estudo objetivou testar experimentalmente a existência da possível correlação entre a penetração de cimento nos túbulos dentinários e a qualidade do selamento. Foram utilizados 60 incisivos centrais superiores humanos que formaram um único grupo experimental. Após a eliminação das porções coronárias, as raízes foram padronizadas em 13 mm de comprimento. A instrumentação dos canais foi realizada no sentido coroa-ápice, e o comprimento de trabalho estabelecido a 1 mm aquém do forame apical. Como solução irrigadora foi empregado o NaOCl a 5,25% e ao final, EDTA a 17%. Em seguida, todos os canais foram obturados com guta-percha e cimento AH Plus marcado com um corante fluorescente. Para determinar a qualidade do selamento das obturações endodônticas, as amostras foram submetidas ao modelo de infiltração de glicose sob pressão. As raízes foram montadas em um dispositivo de dupla-câmara selada para permitir a infiltração da glicose. Como controle negativo foram utilizados 4 dentes hígidos, e como controle positivo, 2 dentes instrumentados porém, não obturados. Foram utilizados 0,75 mL de solução de glicose a 1 mol/L na câmara superior e 0,75 mL de água deionizada na câmara inferior. Os dispositivos foram conectados a um sistema de distribuição de pressão desenvolvido com o objetivo de permitir a infiltração de 32 amostras em uma mesma etapa. A solução de glicose foi forçada apicalmente sob uma pressão de 15 psi durante 1 hora. Uma alíquota de 50 µL foi coletada da câmara inferior para quantificar a glicose infiltrada. A concentração de glicose foi determinada através de um método enzimático com o auxílio do Kit Glucose HK e de um espectrofotômetro em um comprimento de onda de 340 nm. Na sequência, as amostras foram desacopladas dos corpos de prova, embutidas em resina epóxi e cortadas em 3 secções transversais. Uma sequência de preparação metalográfica padrão foi realizada para permitir a observação da penetração de cimento nos túbulos dentinários ...
The purpose of the present study was to experimentally test the potential correlation between tubular dentin sealer penetration and sealability. Sixty human maxillary central incisors were selected in order to compose a single experimental group. After removing of crowns, the roots were standardized at 13 mm in length. A crown-down root canal instrumentation was performed 1mm short of the apical foramen (working length). How irrigating solution was used 5.25% NaOCl and final, 17% EDTA. Then, all root canals were filled with gutta percha and AH Plus sealer labeled with a fluorescent dye. To determine the sealability pattern, samples were submitted to glucose leakage model under pressure. Four intact teeth were used as negative control while further 2 instrumented but nonfilled teeth was used as positive control. The roots were mounted in a double-chamber apparatus where 0,75 mL of 1 mol/L glucose solution was placed into the superior chamber and 0,75 mL of deionized water was placed into the inferior chamber. The devices were connected to a pressure distribution system that was developed in order to allow testing 32 specimens at the same experimental stage. The glucose solution was forced apically under a pressure of 15 psi during 1 hour. A sample of 50 µL was taken from the inferior chamber and the glucose concentration was measured following an enzymatic reaction using a Glucose HK Kit readed under spectrophotometry (wave-length of 340 nm). After that, the samples were removed from the apparatus, embedded in epoxy resin and cut into 3 sections. Standard metallographic preparation was performed prior the observation of the sealer penetration into dentinal tubules by confocal and optical microscopy. Data provided by the evaluations were submitted to Spearman correlation test which revealed a lack of correlation between the two variables (r = 0.12). Therefore, the present study concluded that there was no correlation between tubular sealer ...
Asunto(s)
Humanos , Cementos Dentales , Materiales de Obturación del Conducto Radicular , Obturación del Conducto Radicular , Filtración Dental , Cavidad Pulpar , Glucosa , Gutapercha , Incisivo , Microscopía ConfocalRESUMEN
Permeability involves the passage of fluids, ions, molecules, particulate matter and bacteria into and through a substance or tissue under different and varying conditions. The permeability of the dentin is essential to support the physiology and reaction patterns of the pulp-dentin organ. Nutrients and impulses are transported from the pulp via the odontoblast process and the contents of its tubules maintain the dentin as a vital tissue. However, the main interest of this paper focuses on penetration from the outside towards the pulp rather than from the pulp towards the outside. The present overview centers on the dentinal tubules; how they are formed and how they change as a result of normal and abnormal function, age, and pathological processes and the effect of these processes on the permeability of dentin. Particular attention is focused on the patency of the dentinal tubules.This overview is largely based on the authors own research, clinical insights and active participation in continuing dental education over the last 50 years. It is not a review of the literature related to the permeability of dentin. Rather it presents interpretation of results related to the permeability of dentin based on experience and opinions acquired over a lifetime in dental research.
A permeabilidade envolve a passagem de fluidos, íons, moléculas, material particulado e bactérias para o interior e através de uma substância ou tecido sob diferentes e variáveis condições. A permeabilidade da dentina é essencial para a fisiologia e para os padrões de reação do órgão dentino-pulpar. Nutrientes e impulsos são transportados a partir da polpa por meio dos processos odontoblásticos e o conteúdo dos seus túbulos mantém a vitalidade da dentina. Entretanto, o principal interesse deste artigo concentra-se na penetração do exterior para a polpa e não da polpa para o exterior. O presente artigo centra-se essencialmente nos túbulos dentinários; como eles são formados e como eles mudam em razão da função normal e anormal, idade e processos patológicos, e o efeito destes processos na permeabilidade da dentina. Especial atenção é dada à patência dos túbulos dentinários. Este artigo apresenta uma visão geral do assunto e baseia-se amplamente nas pesquisas e percepções clinicas do próprio autor e em sua ativa participação na educação odontológica continuada ao longo dos últimos 50 anos. Não se trata de uma revisão da literatura relacionada à permeabilidade dentinária, mas sim da interpretação de resultados relacionados à permeabilidade dentinária com base na experiência e opiniões formadas ao longo de toda uma vida dedicada à pesquisa odontológica.