Root canal contamination or exposure to lipopolysaccharide differentially modulate prostaglandin E 2 and leukotriene B 4 signaling in apical periodontitis

Abstract Purpose To evaluate the kinetics of apical periodontitis development in vivo , induced either by contamination of the root canals by microorganisms from the oral cavity or by inoculation of bacterial lipopolysaccharide (LPS) and the regulation of major enzymes and receptors involved in the arachidonic acid metabolism. Methodology Apical periodontitis was induced in C57BL6 mice (n=96), by root canal exposure to oral cavity (n=48 teeth) or inoculation of LPS (10 µL of a suspension of 0.1 µg/µL) from E. coli into the root canals (n= 48 teeth). Healthy teeth were used as control (n=48 teeth). After 7, 14, 21 and 28 days the animals were euthanized and tissues removed for histopathological and qRT-PCR analyses. Histological analysis data were analyzed using two-way ANOVA followed by Sidak's test, and qRT-PCR data using two-way ANOVA followed by Tukey's test (α=0.05). Results Contamination by microorganisms led to the development of apical periodontitis, characterized by the recruitment of inflammatory cells and bone tissue resorption, whereas inoculation of LPS induced inflammatory cells recruitment without bone resorption. Both stimuli induced mRNA expression for cyclooxygenase-2 and 5-lipoxygenase enzymes. Expression of prostaglandin E 2 and leukotriene B 4 cell surface receptors were more stimulated by LPS. Regarding nuclear peroxisome proliferator-activated receptors (PPAR), oral contamination induced the synthesis of mRNA for PPARδ, differently from inoculation of LPS, that induced PPARα and PPARγ expression. Conclusions Contamination of the root canals by microorganisms from oral cavity induced the development of apical periodontitis differently than by inoculation with LPS, characterized by less bone loss than the first model. Regardless of the model used, it was found a local increase in the synthesis of mRNA for the enzymes 5-lipoxygenase and cyclooxygenase-2 of the arachidonic acid metabolism, as well as in the surface and nuclear receptors for the lipid mediators prostaglandin E2 and leukotriene B4.

Influence of photobiomodulation therapy on root development of rat molars with open apex and pulp necrosis

Abstract This study aimed to evaluate the role of photobiomodulation (PBM) in apexification and apexogenesis of necrotic rat molars with an open apex. Rat molars were exposed to the oral environment for 3 weeks. Canals were rinsed with 2.5% NaOCl and 17% EDTA, filled with antibiotic paste and sealed. After 7 days, canals were rinsed and divided into six groups (n=6): mineral trioxide aggregate (MTA); blood clot (BC); human dental pulp stem cells (hDPSC); MTA+PBM; BC+PBM; and hDPSC+PBM. In hDPSC groups, a 1% agarose gel scaffold was used. Two groups were not exposed: healthy tooth+PBM (n = 6), healthy tooth (n = 3); and one was exposed throughout the experiment: necrotic tooth (n = 3). In PBM groups, irradiation was performed with aluminum gallium indium phosphide (InGaAlP) diode laser for 30 days within 24-h intervals. After that, the specimens were processed for histological and immunohistochemical analyses. Necrotic tooth showed greater neutrophil infiltrate (p < 0.05). Necrotic tooth, healthy tooth, and healthy tooth+PBM groups showed absence of a thin layer of fibrous condensation in the periapical area. All the other groups stimulated the formation of a thicker layer of fibers (p < 0.05). All groups formed more mineralized tissue than necrotic tooth (p < 0.05). PBM associated with MTA, BC, or hDPSC formed more mineralized tissue (p < 0.05). MTA+PBM induced apexification (p < 0.05). Rabbit polyclonal anti-bone sialoprotein (BSP) antibody confirmed the histological findings of mineralized tissue formation, and hDPSC groups exhibited higher percentage of BSP-positive cells. It can be concluded that PBM improved apexification and favored apexogenesis in necrotic rat molars with an open apex.

Pulp canal obliteration after traumatic injuries in permanent teeth - scientific fact or fiction?

Abstract: Pulp canal obliteration (PCO) is a frequent finding associated with pulpal revascularization after luxation injuries of young permanent teeth. The underlying mechanisms of PCO are still unclear, and no experimental scientific evidence is available, except the results of a single histopathological study. The lack of sound knowledge concerning this process gives rise to controversies, including the most suitable denomination. More than a mere semantic question, the denomination is an important issue, because it reflects the nature of this process, and directly impacts the treatment plan decision. The hypothesis that accelerated dentin deposition is related to the loss of neural control over odontoblastic secretory activity is well accepted, but demands further supportive studies. PCO is seen radiographically as a rapid narrowing of pulp canal space, whereas common clinical features are yellow crown discoloration and a lower or non-response to sensibility tests. Late development of pulp necrosis and periapical disease are rare complications after PCO, rendering prophylactic endodontic intervention useless. Indeed, yellowish or gray crown discoloration may pose a challenge to clinicians, and may demand endodontic intervention to help restore aesthetics. This literature review was conducted to discuss currently available information concerning PCO after traumatic dental injuries (TDI), and was gathered according to three topics: I) physiopathology of PCO after TDI; II) frequency and predictors of pulpal healing induced by PCO; and III) clinical findings related to PCO. Review articles, original studies and case reports were included aiming to support clinical decisions during the follow-up of teeth with PCO, and highlight future research strategies.

Etiologic role of root canal infection in apical periodontitis and its relationship with clinical symptomatology

Abstract: Evidence shows the polymicrobial etiology of endodontic infections, in which bacteria and their products are the main agents for the development, progression, and dissemination of apical periodontitis. Microbial factors in necrotic root canals (e.g., endotoxin) may spread into apical tissue, evoking and supporting a chronic inflammatory load. Thus, apical periodontitis is the result of the complex interplay between microbial factors and host defense against invasion of periradicular tissues. This review of the literature aims to discuss the complex network between endodontic infectious content and host immune response in apical periodontitis. A better understanding of the relationship of microbial factors with clinical symptomatology is important to establish appropriate therapeutic procedures for a more predictable outcome of endodontic treatment.

Murine Experimental Root Canal Infection: Cytokine Expression in Response to F. nucleatum and E. faecalis

Abstract The aim of this study was to evaluate the gene expression of proinflammatory (RANKL, TNF-a and IFN-g) and regulatory (TGF-b and IL-10) cytokines as reaction to experimental infection by mono or bi-association of Fusobacterium nucleatum (ATCC 10953) and Enterococcus faecalis (ATCC 19433). F. nucleatum and E. faecalis, either in mono- or bi-association were inoculated into the root canal system (RCS) of Balb/c mice. Animals were sacrificed at 10 and 20 days after infection and periapical tissues surrounding the root were collected. The mRNA expression of the cytokines RANKL, TNF-a, IFN- g, TGF-b and IL-10 was assessed using real-time PCR. The Kruskal-Wallis test was used for statistical analysis. F. nucleatum mono-infection induced high expression of RANKL and TNF-a, while its modulation was due to IL-10. High expression of IFN-g at day 20 was up-regulated by E. faecalis and RANKL; TNF-a was up-regulated by an independent mechanism via IL-10 and TGF-b. Bi-association (F. nucleatum and E. faecalis) stimulated high expression of RANKL, TNF-a and IFN-g, which seemed to be modulated by TGF-b 20 days later. The gene expression of proinflammatory cytokines was more prominent in the earlier periods of the experimental periapical infection, which concomitantly decreased in the later period. This expression may be regulated by IL-10 and TGF-b in an infection-specific condition

Resumo O objetivo deste trabalho foi avaliar a expressão gênica de citocinas pró-inflamatórias (RANKL, TNF-a e IFN-g) e regulatórias (TGF-b e IL-10) em resposta à infecção experimental por Fusobacterium nucleatum (ATCC 10953) e Enterococcus faecalis (ATCC 19433) como mono-infecção ou em bi-associação. F. nucleatum e E. faecalis foram inoculados no sistema de canais radiculares de camundongos Balb/c, tanto isoladas como em bi-associação. Os animais foram sacrificados em 10 e 20 dias após a infecção, e os tecidos periapicais foram coletados. As expressões do mRNA das citocinas RANKL, TNF-a, IFN-g, TGF-b e IL-10 foram analisadas por meio do real-time PCR. O teste de Kruskal-Wallis foi utilizado para análise estatística. A mono-infecção com F. nucleatum induziu alta expressão de RANKL e TNF-a, enquanto sua modulação ocorreu devido à IL-10. A alta expressão de IFN-g no dia 20 foi regulada positivamente por E. faecalis e RANKL; TNF-a foi regulada positivamente por um mecanismo independente via IL-10 e TGF-b. A bi-associação (F. nucleatum e E. faecalis) estimulou uma alta expressão de RANKL, TNF-a e IFN-g, que parece ser modulada por TGF-b após 20 dias. A expressão gênica de citocinas pró-inflamatórias foi mais proeminente nos estágios iniciais da infecção periapical experimental, com concomitante redução no período tardio. Este fenômeno pode ser regulado por IL-10 e TGF-b em uma condição de infecção específica.

Obliteração pulpar cronica após traumatismo dentário e tratamento ortodôntico: relato de caso / Chronic pulp canal obliteration after dental trauma and orthodontic treatment: a case report

Introdução: descrever o tratamento endodôntico de incisivos inferiores com obliteração pulpar crônica (OPC) e periodontite apical após trauma dentário e tratamento ortodôntico prolongado. Relato de caso: paciente do sexo feminino, 22 anos de idade, procurou atendimento em uma clínica de Pós-graduação em Endodontia, relatando ter sofrido trauma dentário na região anteroinferior, seguido por tratamento ortodôntico por cinco anos. Dois nos após o nal do tratamento ortodôntico, lesões radiolúcidas associadas aos incisivos centrais inferiores foram observadas e o tratamento endodôntico foi iniciado por um clínico geral, sem sucesso na localização dos canais, devido à OPC. O tratamento endodôntico foi proposto e, com o auxílio de magni cação por microscopia óptica (25X), a localização dos canais foi feita. Movimentos de inserção, retração e rotação de 1/4 de volta nos sentidos horário e anti-horário com uma lima K #10 pré-curvada foram feitos até a patência apical. A intrumentação dos canais foi feita com a técnica do pré-alargamento e a medicação intracanal foi à base de pasta de hidróxido de cálcio, paramonoclorofenol e glicerina, por 15 dias, seguida pela obturação termoplasti cada e restauração com resina fotopolimerizável. Resultados: após 12 meses, a paciente não apresentou sinais e sintomas, e ocorreu o completo reparo das lesões perirradiculares dos incisivos centrais inferiores. Conclusão: a OPC causada pela associação do trauma dentário ao tratamento ortodôntico prolongado pode ter evoluído para a necrose pulpar e, consequentemente, para a periodontite apical. O protocolo de localização, exploração, limpeza, modelagem, medicação intracanal e preenchimento dos canais radiculares evitou as complicações por iatrogenia e permitiu o sucesso do caso.

Resolução de complicações clínicas em casos de obliteração cálcica da polpa: relato de dois casos / Management of clinical complications fol- lowing pulp canal obliteration: a report of two cases

Introdução: a obliteração cálcica da polpa (PCO), é de nida como a deposição de tecido mineralizado no espaço do canal radicular. Tal alteração pode ocorrer de forma idiopática ou após capeamento direto ou trauma. Nessas situações, o clínico pode se deparar com um canal de negociação difícil ou impossível, com alto risco de insucesso. Nesse complexo cenário, o clínico deverá estar preparado para empregar diferentes condutas para resolução do caso. Quando uma região estética se encontra envolvida, os esforços clínicos devem ser ainda mais judiciosos. O presente trabalho tem por objetivo apresentar e discutir os métodos empregados na resolução clínica de dois casos clínicos de incisivos centrais superiores com PCO que apresentavam complicações iatrogênicas prévias.

Complicaciones derivadas del absceso dentoalveolar agudo en pacientes pertenecientes al área VII, Cienfuegos (2013) / Complications caused by acute dentoalveolar abscess in patients from Health Area VII in Cienfuegos, 2013

Introducción: las complicaciones derivadas del absceso dentoalveolar agudo constituyen un tema de preocupación para el estomatólogo, debido al riesgo que generan para el estado de salud en general, a pesar de esto existen pocos estudios específicos sobre el tema. Objetivo: describir las complicaciones derivadas del absceso dentoalveolar agudo en pacientes pertenecientes al área VII, Cienfuegos. Métodos: se realizó investigación observacional, descriptiva, transversal en el periodo comprendido de enero a diciembre de 2013. El universo fue de 374 pacientes que acudieron con absceso alveolar agudo, y la muestra 87 que derivaron en alguna complicación. La fuente para obtener información fue la observación. El registro primario de datos y recolección de la información se obtuvo mediante la historia clínica individual, luego de obtener el consentimiento informado de los pacientes. Principales variables: edad, sexo, dientes afectados con mayor frecuencia, comportamiento de las complicaciones ante tratamiento de elección y automedicación, factores sistémicos asociados y complicaciones derivadas del absceso dentoalveolar agudo. Los resultados se expresaron en total y porcentajes. Resultados: el sexo femenino estuvo afectado con las complicaciones derivadas del absceso dentoalveolar agudo (72,41 por ciento), y el grupo de edad de 35-59 años en 34,48 por ciento. El segundo premolar superior se afectó en 28,74. El 71,26 por ciento respondió de manera positiva ante tratamiento de elección. La diabetes mellitus tipo I y II como factor sistémico se mostró en 53,33 por ciento; la celulitis facial odontógena leve apareció como complicación en 64,36 por ciento. Conclusión: Las complicaciones derivadas del absceso dentoalveolar agudo fueron la celulitis facial odontógena leve y moderada; las mujeres fueron las más afectadas. El padecimiento de enfermedades sistémicas agravó más el cuadro clínico; pero el rápido tratamiento indicado por el facultativo para impedir casos, fatales(AU)

Introduction: complications caused by acute dentoalveolar abscess are a reason for concern among dentists, due to the risk they pose for the patients' overall health status. However, few specific studies have been published on the subject. Objective: describe the complications caused by acute dentoalveolar abscess in patients from Health Area VII in Cienfuegos. Methods: a cross-sectional observational descriptive study was conducted from January to December 2013. The study universe was 374 patients attending the dental service with acute alveolar abscess, and the sample was 87 who had some sort of complication. Data were obtained by observation. Primary data and information were collected from the patients' medical records after obtaining their informed consent. The main variables analyzed were age, sex, teeth most commonly affected, behavior of complications vs. treatment of choice and self-medication, associated systemic factors and complications caused by acute dentoalveolar abscess. Results were expressed as total and percentages. Results: 72.41 percent of the female patients and 34.48 percent of the 35-59 age group were affected by complications caused by acute dentoalveolar abscess. The upper second premolar was affected in 28.74 percent of the cases. 71.26 percent of the patients responded positively to the treatment of choice. Diabetes mellitus types I and II as a systemic factor was found in 53.33 percent of the cases, whereas mild odontogenic facial cellulitis appeared in 64.36 percent. Conclusion: mild and moderate odontogenic facial cellulitis were the complications caused by acute dentoalveolar abscess. Women were more affected than men. Systemic diseases aggravated the clinical status of patients, but the swift action of dentists prevented the occurrence of fatal cases(AU)

Prevalencia de enfermedades pulpares y periapicales en pacientes geriátricos: Mérida, Yucatán, México / Prevalence of pulpal and periapical disease among geriatric patients in Mérida, Yucatán, Mexico

Introducción: las consideraciones médicas, psicológicas y biológicas en la población de personas mayores es una responsabilidad social que todo profesional deberá atender con sumo cuidado, ya que este grupo etario es más susceptible a presentar diversas enfermedades, entre las que se encuentran las pulpares y las periapicales. Objetivo: determinar la prevalencia de enfermedades pulpares y periapicales en pacientes de 60 y más años de edad en pacientes geriátricos de la Facultad de Odontología de la Universidad Autónoma de Yucatán, México. Métodos: estudio descriptivo, prospectivo, transversal y observacional. El universo estuvo constituido por los pacientes que acudieron a la Clínica de Admisión de la Facultad de Odontología de la Universidad Autónoma de Yucatán, México durante el periodo comprendido de agosto a diciembre de 2012. La muestra fue de 74 paciente de 60 y más años de edad, con alguna afección pulpar o periapical, que aceptaron participar en el estudio. Se les realizó: entrevista por medio de un formulario de historia odontológica que permitió al paciente describir su experiencia de dolor de un modo organizado, breve y descriptivo; examen clínico y pruebas pulpares: térmicas, percusión y palpación; estudio radiográfico. Se utilizó estadística descriptiva y pruebas chi cuadrado. Resultados: se revisaron 108 órganos dentarios. El 41,67 pr ciento (n= 45) presentó patologías pulpares: 22,22 por ciento (n= 10) pulpitis reversible, 57,78 por ciento (n= 26) pulpitis irreversible y 20 por ciento (n= 9) necrosis pulpar. El 58,33 por ciento (n= 63) patologías periapicales: 42,85 por ciento (n= 27) periodontitis apical aguda, 15,87 por ciento (n= 10) periodontitis apical crónica, 1,58 por ciento (n= 1) quiste apical, 27 por ciento (n= 17) absceso apical agudo y 12,70 por ciento (n= 8) absceso apical crónico. Conclusión: no se obtuvo diferencias significativas entre el número de dientes que presentaron enfermedades pulpares y el número de dientes que presentaron enfermedades periapicales en este grupo etario(AU)

Introduction: medical, psychological and biological factors should be carefully considered by health professionals when dealing with elderly patients, for this age group is more prone to a number of conditions, among them pulpal and periapical disease. Objective: determine the prevalence of pulpal and periapical disease among patients aged 60 and over attending the School of Dentistry of the Autonomous University of Yucatán, Mexico. Methods: a descriptive cross-sectional observational prospective study was conducted. The study universe was composed of the patients attending the Outpatient Clinic at the School of Dentistry of the Autonomous University of Yucatán, Mexico, from August to December 2012. The sample was 74 patients aged 60 and over with some pulpal or periapical condition who accepted to participate in the study. An interview was conducted based on a dental history form allowing patients to describe their pain experience in a brief, descriptive, organized manner. Clinical examination was performed, as well as pulpal tests: thermal, percussion and palpation, and a radiographic study. Analysis was based on descriptive statistics and chi square tests. Results: 108 dental organs were examined. 41.67 percent (n= 45) presented the following pulpal pathologies: reversible pulpitis 22.22 percent (n= 10), irreversible pulpitis 57.78 percent (n= 26) and pulp necrosis 20 percent (n= 9). 58.33 percent (n= 63) presented the following periapical pathologies: acute apical periodontitis 42.85 percent (n= 27), chronic apical periodontitis 15.87 percent (n= 10), apical cyst 1.58 percent (n= 1), acute apical abscess 27 percent (n= 17) and chronic apical abscess 12.70 percent (n= 8). Conclusion: no significant differences were found between the number of teeth with pulpal disease and the number of teeth with periapical disease in this age group(AU)

Management of an internal root resorption on a permanent tooth: a case report / Manejo de una reabsorción radicular interna en una pieza permanente: reporte de caso

Internal root resorption (IRR) is a rare pulp disease. Its etiology involves late pulpal inflammations and trauma, among others. IRR may also show some symptoms, and is usually detected by X-rays. However, its diagnosis is significantly improved by the use of cone beam computed tomography (CBCT). The objective of this case report was to account for the diagnosis and management of an internal root resorption without perforation. The patient, a 26-year-old male, went to the School of Dentistry at Universidad Andres Bello, Concepción, without having symptoms in the tooth 1.1. Anamnesis revealed the presence of previous symptoms. CBCT examination showed absence of bowl-shaped calcified dentin tissue on the inner walls of the root canal with apical lesion but without perforation of surrounding tissues. Endodontic treatment was performed using the following methods: irrigation of the root canal with 2 percent chlorhexidine (CHX) using a Max-i-probe cannula and simultaneous cavitation of the irrigant Then calcium hydroxide (CH) was applied as intracanal medication for a week and Schilder’s technique for vertical compaction was used. The patient was checked after one week and then after six months. He did not have any symptoms. Early diagnosis using modern imaging equipment, appropriate use of ultrasound for chemomechanical debridement and thermoplastic filling techniques contribute to a more favorable prognosis of patients with internal root resorption...

La reabsorción radicular interna (RRI) es una condición pulpar poco común, cuyo origen etiológico incluye procesos inflamatorios tardíos de la pulpa, traumatismos, entre otros; por otra parte ésta podría presentar sintomatología. Generalmente es detectada por hallazgo radiográfico, sin embargo, requiere de un mejor método de diagnóstico por imagen como es la tomografía computarizada cone beam (TCCB). El objetivo de este reporte de caso fue detallar el diagnóstico y manejo de una reabsorción radicular interna sin perforación. El paciente de sexo masculino, 26 años de edad acudió a la Facultad de Odontología de la Universidad Andrés Bello sede Concepción, sin presentar síntomas en el diente 1.1. La anamnesis refirió presencia de sintomatología con anterioridad. La evaluación mediante la TCCB demostró ausencia de tejido dentinario calcificado en forma de cuenco en las paredes internas del conducto radicular con presencia de lesión apical sin evidenciar perforación hacia tejidos circundantes. Se realizó el tratamiento endodóntico, usando los siguientes métodos: el conducto radicular se irrigó con Clorhexidina (CHX) al 2 por ciento usando cánula Max-i-probe y simultáneamente fue realizada la cavitación del irrigante, luego se colocó Hidróxido de Calcio (HC) como medicación intraconducto por una semana. Se usó la técnica de compactación vertical de Schilder más un control del paciente a la semana y a los 6 meses. El paciente no presentó sintomatología. El diagnóstico temprano mediante herramientas imaginológicas contemporáneas, la utilización del ultrasonido para el desbridamiento químico-mecánico y las técnicas de obturación termoplásticas usadas acorde al caso hacen que las piezas con reabsorción radicular interna tengan un pronóstico más favorable...

Comparison of the ability to preserve the central axis of a canal after instrumentation using the ProTaper Universal© and EndoWave systems / Comparação da habilidade em preservar o eixo central do canal após instrumentação utilizando os sistemas ProTaper Universal© e EndoWave

O objetivo deste estudo foi comparar ex vivo a capacidade de manutenção do eixo central do canal após a instrumentação com dois sistemas rotatórios de n¡quel titânio: sistema ProTaper Universal© e sistema EndoWave©. Para tanto, foram utilizados para o estudo 20 raízes mesiais de molares inferiores que possuíam canais mesiais separados em todo o eixo longitudinal que foi avaliado antes e depois da instrumentação, usando-se a metodologia de avaliação de imagens transversais das raízes pré e pós-instrumentação proposta por Bramante4 (1987) e modificada por Kuttler14 (2001). Foram realizados os acessos, e os comprimentos de trabalho (CT) foram padronizados em 18.00 mm. As amostras foram incluídas em resina acrílica dentro da mufla. Os dentes foram seccionados a 3, 6 e 9 milímetros do  pice radicular e imagens pré-instrumentação foram obtidas dos cortes transversais através de método fotográfico. As amostras foram remontadas no cubo endodôntico e posteriormente 20 canais foram preparados com o sistema ProTaper Universal© e 20 canais foram preparados com o sistema EndoWave©. Foram realizadas novas imagens pós-instrumentação, que foram sobrepostas e avaliadas por meio do programa AutoCad© para determinar o desvio do eixo central do canal após o preparo endodêntico. Os dados obtidos foram submetidos … análise estatística, através do teste Two-Way ANOVA. O nível de significância foi de 5%. Os canais vestibulares e linguais das seções a 3, 6 e 9 mm do  pice mostraram um leve desvio do eixo central do canal após a instrumentação (0.109 mm para o sistema Protaper Universal© e 0.112 mm para o sistema EndoWave©), porém não houve diferenças estatisticamente significativas no desvio entre os dois sistemas em nenhum nível da raiz. Desta forma, a instrumentação com qualquer um dos dois sistemas pesquisados propiciou a manutenção do eixo central dos canais sem alterações significativas.

The aim of this study was to compare ex vivo the ability to preserve the central axis of a canal after instrumentation with two nickel-titanium rotary systems: ProTaper Universal© and EndoWave©. Twenty mesial roots of mandibular molars with separated mesial roots all along the longitudinal axis were assessed before and after instrumentation using a cross-sectional image assessment methodology for pre and post-instrumentation roots, as proposed by Bramante4 (1987) and modified by Kuttler14 (2001). Accesses were performed, the working length (WL) was standardized to 18.00 mm, and samples were embedded in acrylic resin inside a muffle. The teeth were cut at 3, 6, and 9 mm from the apex and pre-instrumentation images were obtained from cross sections through a photographic method. Samples were reassembled in the endodontic cube and subsequently prepared; 20 canals were prepared with the ProTaper Universal© system, and 20 canals were prepared with the EndoWave© system. New images were taken after instrumentation, which were overlapped and evaluated with AutoCad©, a computer graphics program to determine the deviation from the central axis of the canal after endodontic preparation. Data gathered underwent statistical analysis through the Two-Way ANOVA test. The significance level was 5%. Buccal and lingual canals for those sections at 3, 6, and 9 mm from the apex showed a slight deviation from the central axis of the canal after instrumentation (0.109 mm for the ProTaper Universal© and 0.112 mm for the EndoWave©), but there was no statistically significant differences in deviation between the two systems at any level of the root. Thus, instrumentation with any of the two systems under investigation provided for preservation of the central axis of the canals with no significant changes

Avaliação da expressão de integrina alfa2, proteína de choque térmico 47, e mediadores pro-inflamatórios e imunorregulatórios em resposta à infecção endodôntica / To examine alpha 2 integrin, molecular mediators, cytokines, and chemokines from cells in periapical interstitial fluid from root canal infections

Objetivo: analisar a expressão de integrina alfa2, mediadores moleculares, citocinas e quiocinas, a partir de células presentes no líquido interstical periapical adjacente e dentes portadores de infecção dos canais radiculares. Metodologia: os 13 pacientes incluídos no estudo foram encaminhados à Faculdade de Odontologia da Universidade Federal de Minas Gerais (Belo Horizonte, MG, Brasil). As amostras foram retiradas de dentes com necrose pulpar e nenhum paciente apresentou sintomas periapicais agudos no momento das coletas (...) Resultados: Observaram-se níveis significativamente mais baixos de TNF-α, CCL5, CCL2 / MCP-1 e IL8 em dentes com cargas bacterianas redusidas...

Frequency of second canal in mandibular lateral incisors [in-vitro]

Objective of the study was to determine the frequency of second canal in extracted mandibular lateral incisors. It was observational study and was conducted in the Dental Outpatient's Department of Liaquat University of Medical and Health Sciences Hospital, Hyderabad / Jamshoro from 1st January 2010 to 31th March 2010. This study included 100 extracted permanent mandibular lateral incisors. These extracted teeth were stored in 10% formalin until access preparation was made. Pulp chamber was accessed using round bur and then irrigated with sodium hypochlorite till it is clearly visible. Then DG16 endodontic explorer was used for the location and negotiation of second canal after location of main canal. Teeth in which second canal was located, No. 10 K-files were inserted into main canal and second canal. Then two periapical radiographs from the buccolingual and proximal sides were taken for confirmation. Results were then recorded in proforma. Single canal was found in 61% of permanent mandibular lateral incisors. 39% of permanent mandibular lateral incisors had second canal. The frequency of second canal in the present study was 39% of permanent mandibular lateral incisors

A finite element thermal analysis of various dowel and core materials.

Aim: Thermal analysis of the temperature and stress distribution of parallel sided, threaded and non-threaded dowels and core materials under thermal loading within a maxillary central incisor using a three dimensional finite element study. Materials and Methods: 3D models of endodontically treated maxillary central incisor with parallel sided, threaded and non- threaded post and core materials were simulated using the ANSYS software. Materials simulated were parallel sided cast gold post and core, parallel sided fibre reinforced composite (FRC) post and core, and parallel sided, threaded, prefabricated stainless steel post and amalgam core. Thermal loads simulating hot (60 degree C/ 333K) and cold (15 degree C/288K) liquid were applied for 15 seconds at the incisal edge. The temperature changes at the selected nodes were obtained on the various post and core materials, interface between post and dentin, interface between core and dentin, within the dentin and within the cement layer. Results: Temperature and stress distribution pattern were represented in numerical and color coding and results interpreted. Thermal stresses arises as a result of temperature changes. A decreased temperature gradient of the metallic dowels and core (T1 hot - 0.002K, T3 hot - 1.071K, T1 cold -0.99K, T3 cold - 0K) were obtained than that of the FRC dowel and core of 1.982K(hot) and1.55K(cold) respectively due to the higher thermal conductivity of the metals. Higher thermal stress values of 3.567 Mpa(hot) and 3.092 Mpa(cold) respectively were obtained for the FRC dowels and higher stress values of 39.679 Mpa(hot) and 57.855 Mpa(cold) respectively were also obtained for the FRC cores. These values indicated that thermal stresses of the FRC dowel and core were greater than that of cast gold dowel and core and prefabricated stainless steel dowel and amalgam core due to its high coefficient of thermal expansion. Maximum stress values of the FRC dowel and core of 1.87 Mpa(hot) and 2.57 Mpa(cold) respectively were also generated in the cement layer, core and metal ceramic crown. The junction of the metal ceramic crown and dentin demonstrated the maximum stress. Higher thermal stress values of 59.162 ± 10 Mpa were obtained in the restoration and the coronal portion of the dentin than the stress levels of .0039 ± 10Mpa in the supporting bone due to an increased thermal expansion. Conclusion: Non-metallic dowel and core materials such as fibre reinforced composite dowels (FRC) generate greater stress than metallic dowel and core materials. This emphasized the preferable use of the metallic dowel and core materials in the oral environment.

A biochemical and histopathological evaluation of generalized pulp calcification in young permanent teeth.

Pulp calcifications are a frequent finding on bitewing and periapical radiographs in older age-groups but their occurrence in the entire dentition in young subjects is unusual. We report such an unusual occurrence of generalized pulp calcification in a 13-year-old Indian female. Radiographic examination of the dentition revealed pulp calcifications in all permanent teeth, located mostly in the pulp chamber but with some in the root canals. The patient's dental, medical, and family history was noncontributory. Biochemical analysis of the removed pulp calcification from one of the teeth during endodontic treatment showed large amounts of calcium, phosphorus, and carbonate. However, metabolic evaluation of patient through liver and kidney function tests and other blood investigations did not reveal any metabolic disorder. The patient was also evaluated for any systemic, syndromic, or genetic involvement but this was also noncontributory. Therefore, we propose that this unusual case of generalized pulp calcification is of idiopathic origin. In this work, histopathological and biochemical evaluations of the pulp calcification was done to try and understand the initiation and progress of calcifications in pulpal tissue.

Tissue reaction to Endométhasone sealer in root canal fillings short of or beyond the apical foramen

OBJECTIVE: This study evaluated the response of periapical tissues to the endodontic sealer Endométhasone in root canal fillings short of or beyond the apical foramen. MATERIAL AND METHODS: Twenty root canals of premolars and incisors of 2 mongrel dogs were used. After coronal access and pulp extirpation, the canals were instrumented up to a size 55 K-file and the apical cemental barrier was penetrated with a size 15 K-file to obtain a main apical foramen, which was widened to a size 25 K-file. The canals were irrigated with saline at each change of file. The root canals were obturated either short of or beyond the apical foramen by the lateral condensation of gutta-percha and Endométhasone, originating 2 experimental groups: G1: Endométhasone/short of the apical foramen; G2: Endométhasone/beyond the apical foramen. The animals were killed by anesthetic overdose 90 days after endodontic treatment. The individual roots were obtained and serial histological sections were prepared for histomorphological analysis (H&E and Brown & Brenn techniques) under light microscopy. The following parameters were examined: closure of the apical foramen of the main root canal and apical opening of accessory canals, apical cementum resorption, intensity of the inflammatory infiltrate, presence of giant cells and thickness and organization of the apical periodontal ligament. Each parameter was scored 1 to 4, 1 being the best result and 4 the worst. Data were analyzed statistically by the Wilcoxon nonparametric tests (p=0.05). RESULTS: Comparing the 2 groups, the best result (p<0.05) was obtained with root canal filling with Endométhasone short of the apical foramen but a chronic inflammatory infiltrate was present in all specimens. CONCLUSIONS: Limiting the filling material to the root canal space apically is important to determine the best treatment outcome when Endométhasone is used as sealer.

Obliteração do canal pulpar do incisivo central superior esquerdo de uma paciente jovem após trauma - Acompanhamento clínico-radiográfico / Pulp canal obliteration of upper left central incisor of a young patient after trauma - Monitoring clinical-radiographic

Uma das complicações tardias que podem ocorrer em dentes que sofreram trauma é aobliteração do canal pulpar (OCP). Essa condição torna o dente mais susceptível ao desenvolvimentode necrose pulpar. A conduta clínica após o diagnóstico de OCP não estábem definida. Enquanto alguns cirurgiões-dentistas optam pelo tratamento endodônticoradical, outros elegem o acompanhamento clinicoradiográfico. Esse trabalho teve comoobjetivo apresentar um caso clínico do elemento dentário incisivo central superior esquerdopermanente de uma paciente jovem de 7 anos de idade com OCP após intrusão.O tratamento de escolha foi o acompanhamento clinicoradiográfico e, 18 meses após odiagnóstico, o dente continua apresentando vitalidade pulpar. Embora, os dentes que apresentemobliteração do canal pulpar tenham maior risco de desenvolverem necrose pulpar,o tratamento endodôntico profilático, nesses casos, não deve ser uma conduta de rotina.

One of the late complications that can occur on teeth that have suffered trauma is thepulp canal obliteration (PCO). This condition makes the tooth more susceptible to thedevelopment of pulp necrosis. The clinical management after the diagnosis of OCP isnot well defined. While some dentists opt for radical endodontic treatment, others preferthe monitoring clinical-radiographic. This study aimed to present a clinical case of toothupper left central incisor of a young patient of 7 years of age with OCP after intrusion.The treatment of choice was the monitoring clinical-radiographic and, 18 months afterdiagnosis, the tooth continues to show vitality’signs. Although, teeth showing pulp canalobliteration are at greatest risk of developing pulp necrosis, endodontic prophylactictreatment in such cases should not be a routine practice.

Rotary Mtwo system versus manual K-file instruments: Efficacy in preparing primary and permanent molar root canals.

Aim: To compare the cleaning ability and preparation time of rotary instruments (Mtwo) and conventional manual instruments (K-file) in preparing primary and permanent molar root canals. Materials and Methods: Access cavities were prepared in 70 primary and 70 permanent teeth and India ink was injected into 120 canals of selected molars. The teeth were randomly divided into two main subgroups (n=20) and three control groups (n=10). In each of these main subgroups, either the manual instrument (K-file) or the rotary system (Mtwo) was used to prepare root canals. After cleaning the canals and clearing the teeth, dye removal was evaluated with the help of a stereomicroscope. In addition, the time needed for root canal preparation was recorded by a chronometer. Statistical Analysis: Statistical analyses were done using the Kruskal-Wallis, Mann-Whitney and t tests. Results: With regard to the cleaning ability of root canals, there were no significant differences between the K-file and Mtwo rotary system in primary and permanent teeth in the apical, middle or coronal third of the canals. Moreover, there were no significant differences between primary and permanent teeth prepared with K-files and rotary instruments. In all the groups, shorter times were recorded with the rotary technique. The working time was shorter in primary than in permanent teeth. Conclusion: The Mtwo rotary system showed acceptable cleaning ability in both primary and permanent teeth, and achieved results similar to those of K-files in less time.

Effect of post type and restorative techniques on the strain and fracture resistance of flared incisor roots

Restoring flared endodontically treated teeth continues to be a challenge for clinicians. This study evaluated the effect of post types and restorative techniques on the strain, fracture resistance, and fracture mode of incisors with weakened roots. One hundred five endodontically treated bovine incisors roots (15 mm) were divided into 7 groups (n=15). The two control groups were (C) intact roots restored with Cpc (cast posts and core) or Gfp (glass fiber posts). The five experimental groups were (F) flared roots restored with GfpAp (Gfp associated with accessory glass fiber posts), GfpRc (anatomic Gfp, relined with composite resin), and GfpRcAp (anatomized Gfp with resin and accessory glass fiber posts). All teeth were restored with metal crowns. Mechanical fatigue was performed with 3x10(5)/50 N. Specimens were loaded at 45º, and the strain values (μS) were obtained on root buccal and proximal surfaces. Following that, the fracture resistance (N) was measured. One-way ANOVA and Tukey's HSD tests (α=0.05) were applied, and failure mode was checked. No significant difference in strain values among the groups was found. Cpc presented lower fracture resistance and more catastrophic failures in flared roots. Gfp associated with composite resin or accessory glass fiber posts seems to be an effective method to improve the biomechanical behavior of flared roots.

Restaurar dentes tratados endodonticamente continua sendo desafio para clínicos. Este estudo avaliou o efeito de pinos e técnicas na deformação, resistência à fratura e padrão de fratura de incisivos com canal radicular alargado. Cento e cinco raízes bovinas, tratadas endodonticamente (15 mm) foram divididas em 7 grupos (n=15). Os grupos controle (C), constituídos de raízes não alargadas, foram restauradas com Cpc (núcleo metálico fundido) ou Gfp (pino de fibra de vidro). Nos grupos experimentais os canais foram alargados (F) e restaurados com: GfpAp (Gfp associado com pinos de fibra de vidro acessórios); GfpRc (pino anatômico, reembasado com resina composta) e GfpRcAp (pino anatomizado com resina composta e pinos acessórios). Os dentes foram restaurados com coroas metálicas. Fadiga mecânica foi simulada com 3x10(5)/50 N ciclos. O teste foi realizado a 45º e a deformação (μS) obtida nas superfícies vestibular e proximal. Em seguida, a resistência à fratura (N) e o padrão de fratura foram verificados. Aplicou-se ANOVA e Teste de Tukey (α=0,05). Não houve diferença na deformação. Cpc resultou em menor resistência à fratura e com mais fraturas catastróficas em raízes fragilizadas. As técnicas de reembasamento do pino com resina composta ou o uso de pinos acessórios parecem ser efetivos para melhorar o comportamento biomecânico de raízes fragilizadas.

Efficacy of five rotary systems versus manual instrumentation during endodontic retreatment

The purpose of this study was to evaluate the efficiency of ProFile, GT, ProTaper, Race and K3 rotary instruments compared with hand K-files for removal of gutta-percha during retreatment. Sixty mandibular premolars were instrumented with GT rotary files and filled by thermomechanical compaction of gutta-percha and AH Plus sealer. The teeth are randomly divided into 6 groups of 10 specimens each. The roots were split longitudinally, digital images were created using a flatbed scanner, and the areas with remaining filling material were demarcated using Image Tool 1.21 software. The results indicate that GT left significantly less (p<0.05) remaining filling material (1.18 ± 1.47) than hand (3.70 ± 3.16) and Hero instruments (2.99 ± 2.58). There was no statistically significant difference (p<0.05) among the others techniques: ProFile (1.99 ± 2.66), ProTaper (2.00 ± 1.99) and K3 (2.71 ± 2.87) when compared with GT. In conclusion, GT, ProFile, ProTaper and K3 were more effective in removing gutta-percha than manual and Hero instruments.

O propósito deste estudo foi avaliar a eficiência dos instrumentos rotatórios ProFile, GT, ProTaper, Race e K3 comparados com limas K para a remoção do material obturador durante o retratamento. Sessenta pré-molares inferiores foram instrumentados com o sistema rotatório GT e obturados usando a técnica de compactação termomecânica de guta-percha com cimento AH Plus. Os dentes foram divididos aleatoriamente em seis grupos de dez espécimes cada. As raízes foram seccionadas longitudinalmente, imagens digitais foram criadas através de um scanner, e as áreas de remanescentes de material foram medidas usando o programa Image Tool 1.21. Os resultados indicaram que o GT deixou significantemente menos material remanescente (1,18 ± 1,47) do que os instrumentos manuais (3,70 ± 3,16) e os instrumentos Hero (2,99 ± 2,58) (p<0,05). Não houve diferença estatisticamente significante entre as outras técnicas ProFile (1,99 ± 2,66), ProTaper (2,00 ± 1,99) e K3 (2,71 ± 2,87) quando comparadas com o GT. Como conclusão, GT, ProFile, ProTaper e K3 foram revelados como mais efetivos em remover a guta-percha do que os instrumentos manuais e os instrumentos Hero.