Apical root canal microbiome associated with primary and posttreatment apical periodontitis: A systematic review.

BACKGROUND: Microorganisms colonizing the apical root canal system are conceivably the ones directly involved with the causation and maintenance of apical periodontitis. OBJECTIVES: This article systematically reviews the reports on the microbiome occurring exclusively at the apical root canal of teeth with primary and posttreatment apical periodontitis. METHODS: The electronic databases PubMed, Embase, Web of Science, Science Direct, and Proquest were searched up to August 2023. Clinical studies using culture and molecular microbiology methods to identify the microbial taxa present exclusively in the apical root canal segment of infected teeth with apical periodontitis were included. Studies were critically assessed using the Joanna Briggs Institute Critical Prevalence Assessment Checklist. RESULTS: From 2277 articles initially detected, 52 were selected for full reading and 21 were eventually included in this review. Of these, molecular methods were used in 19 and culture in 2 studies. Ten studies evaluated primary infections, 8 evaluated posttreatment infections, and 3 included both. Cryopulverization of the apical root specimens was conducted in 11 studies. All studies evaluated the prevalence and diversity of bacteria, and only one also reported on fungi. Overall, the most frequent/abundant bacterial taxa found in the apical canal of primary infections were Pseudoramibacter alactolyticus, Olsenella uli, Fusobacterium species, Streptococcus species, Porphyromonas endodontalis, Prevotella species, Actinomyces species, Parvimonas micra, Treponema denticola, Synergistetes species, and an as-yet uncharacterized taxon. In posttreatment infections, the most prevalent/abundant bacterial taxa included species of Streptococcus, Enterococcus, Fusobacterium, Actinomyces, Pseudoramibacter, Pseudomonas, and Propionibacterium. At the phylum level, Firmicutes was the most represented. The average apical bacterial load ranged from 105 to 106 in primary infections and from 103 to 104 in posttreatment infections. DISCUSSION: Microbial diversity in the apical part of the root canal system was examined encompassing data from both primary and posttreatment infections. Heterogeneity amongst the studies, especially in sample collection and microbial identification methods, is an important limitation that prevented a meta-analysis. CONCLUSIONS: There is a pronounced bacterial diversity in the infected apical canal, with a high interindividual variability. Different microbiome compositions at the species/genus level are observed according to the infection type. REGISTRATION: PROSPERO CRD42021275886.

Descripción de la Morfología del Sistema de Canales Radiculares en Premolares Maxilares Mediante Tomografía Computarizada Cone Beam en una Población Chilena

El tratamiento endodóntico requiere detallados conocimientos sobre la morfología radicular. En premolares maxilares, se ha reportado variabilidad en el número de raíces y morfología del sistema de canales radiculares (SCR). La causa más frecuente de fracaso endodóntico son los conductos no tratados. Por lo tanto, una mejor compresión de la morfología del SCR y sus variaciones es crucial para el tratamiento endodóntico. El objetivo de esta investigación fue describir la frecuencia del número de raíces y morfología del SCR en premolares maxilares, mediante exámenes de tomografía computarizada Cone Beam (CBCT) en una población chilena. Se realizó un estudio observacional descriptivo de corte transversal donde se observó la morfología del sistema de canales radiculares de primeros y segundos premolares maxilares a través de exámenes CBCT, agrupándolos de acuerdo con la Clasificación de Vertucci. Se observaron 228 exámenes CBCT, donde se incluyeron 268 primeros premolares superiores y 233 segundos premolares maxilares. Se determinó que en primeros premolares maxilares un 56,3 % presentó una raíz, un 43,3 %, siendo más frecuente una morfología del SCR tipo IV. En los segundos premolares maxilares, se determinó la presencia de una raíz en el 95,7 % de los casos, siendo más frecuente una morfología del SCR tipo I. Estos resultados pueden ser de interés para endodoncistas, ya que conocer la morfología del SCR de premolares maxilares permite mejorar la planificación de la terapia endodóntica realizada en estos dientes.

Endodontic treatment requires detailed knowledge of root morphology. In maxillary premolars, variability in root number and root canal system (RCS) morphology has been reported. The most frequent cause of endodontic failure is non treated canals. Therefore, a better understanding of RCS morphology and its variations is crucial for endodontic treatment. The aim of this research was to describe the frequency of root number and SCR morphology in maxillary premolars, by means of Cone Beam Computed Tomography (CBCT) examinations in a Chilean population. A cross-sectional descriptive observational study was carried out in which the morphology of the root canal system of maxillary first and second premolars was observed through CBCT examinations, grouping them according to the Vertucci Classification. A total of 228 CBCT examinations were observed, which included 268 upper first premolars and 233 maxillary second premolars. It was determined that in maxillary first premolars 56.3 % presented one root, 43.3 %, being more frequent a SCR type IV morphology. In maxillary second premolars, the presence of one root was determined in 95.7 % of the cases, being more frequent a SCR type I morphology. These results may be of interest to endodontists, since knowing the morphology of the RCS of maxillary premolars allows improving the planning of endodontic therapy performed on these teeth.

Anatomical complexities affecting root canal preparation: a narrative review.

A fundamental aspect of the Endodontic field is the knowledge of root canal anatomy. Using a variety of techniques, the internal and external anatomy of teeth have been extensively investigated throughout the past century. Recent improvements in three-dimensional computed tomography have enabled more detailed evaluations of root canal morphology in both clinical and laboratory settings. Essentially, researches have unveiled that the root canal constitutes a complex system, comprising not only the main root canal but also lateral components, including isthmuses, fins, accessory canals and apical ramifications. Undoubtedly, this intricate morphology poses a significant challenge when it comes to the process of shaping, cleaning and disinfecting the root canal system. This article aims to explore the anatomical aspects of the root canal system that impact the chemomechanical procedures.

Descripción de la morfología del sistema de canales radiculares del primer molar maxilar mediante tomografía computarizada cone-beam en una población chilena / Description of the morphology of the root canal system of the maxillary first molar using cone-beam computed tomography in a Chilean population

Describir la morfología del sistema de canales radiculares del primer molar maxilar en una población chilena mediante exámenes de tomografía computarizada Cone-Beam (CBCT). Se realizó un estudio observacional descriptivo en el cual se utilizaron los exámenes CBCT de pacientes que fueron atendidos en un Centro de Radiología Maxilofacial privado durante el período comprendido entre Enero y Diciembre del año 2018 en la ciudad de Temuco, Chile, los cuales fueron observados de manera independiente por dos investigadores previamente calibrados. Se observaron 199 exámenes CBCT. En la raíz mesiobucal,predominaron las morfologías tipo II, I y IV de Vertucci respectivamente, mientras que en la raíz distobucal y palatina predominó la morfología tipo I. El canal MB2 estuvo presente en el 62,3 % de los casos, con una prevalencia significativamente mayor en pacientes jóvenes. En la mayoría de los primeros molares maxilares de los habitantes de la ciudad de Temuco se observaron tres raíces separadas y la presencia de cuatro canales. Se determinó una alta frecuencia del canal MB2 en la raíz MB.

SUMMARY: The objective of this study was to describe the morphology of the root canal system of the maxillary first molar in a Chilean population through Cone-Beam computed tomography (CBCT) examinations. A descriptive observational study was carried out in which the CBCT examinations of patients who were treated in a private maxillofacial radiology center during the period between January and December 2018 in Temuco, Chile, were used which were observed independently by two previously calibrated researchers. In this analysis 199 CBCT exams were observed. In the mesiobuccal root, Type II, I and IV morphologies predominated respectively, while in the distobuccal and palatal root, Type I morphology predominated. The MB2 canal was present in 62.3 % of cases, with a higher prevalence in young patients. Three separate roots and the presence of four canals were observed in most of the maxillary first molars of the patients in Temuco. A high frequency of the MB2 canal was determined in the root MB.

Anatomical and morphological findings of the root canal of maxillary premolars and their prevalence: CBCT study in a Mexican population / Hallazgos anatómicos y morfológicos del conducto radicular de premolares maxilares y su prevalencia: estudio CBCT en una población mexicana

SUMMARY: An essential prerequisite to perform any dental procedure is a clear understanding and knowledge of dental anatomy and its possible variations. The root canal system is characterized for a complex morphology, which varies among populations, individuals in the same population and even in the same person. The aim of this study was to evaluate by CBCT the morphology, number, curvature, and length of roots of first and second maxillary premolars in a Mexican population. In this stud 1700 maxillary premolars were evaluated by CBCT scans of patients; the axial, sagittal and coronal sections were analyzed following the longitudinal axis of each tooth. As a result 51.60 % of the maxillary first premolars had a single root, 31.03 % had two roots, 16.29 % had root fusion, and 1.07 % had three roots. 22.3 % of the maxillary first premolars showed mesial curvature, 41.9 % had a distal curvature, and 35.7 % did not show any curvature; and the most prevalent configuration in maxillary first premolars was Type V. 88.9 % of the maxillary second premolars had a single root, 3.9 % had two roots, 6.9 % had root fusion, and 0.11 % had three roots; 37.59 % of the maxillary second premolars showed a mesial curvature and 62.40 % showed a distal curvature; and the most prevalent configuration in maxillary second premolars was Type I. The anatomy of the root canal system is extremely complex and has many anatomical configurations, these clinical situations must be considered previous to performing any endodontic treatment.

RESUMEN: Un requisito esencial previo a la realización de cualquier procedimiento dental es una clara comprensión y conocimiento de la anatomía dental y sus posibles variaciones. El sistema de canales radiculares se caracteriza por una morfología compleja, que varía entre poblaciones, individuos en una misma población e incluso en una misma persona. El objetivo de este estudio fue evaluar mediante CBCT la morfología, número, curvatura y longitud de raíces de primeros y segundos premolares maxilares en una población mexicana. En este estudio se evaluaron 1700 premolares maxilares mediante escaneos CBCT de pacientes; se analizaron los cortes axial, sagital y coronal siguiendo el eje longitudinal de cada diente. El 51,60 % de los primeros premolares maxilares tenían una sola raíz, el 31,03 % tenían dos raíces, el 16,29 % tenían fusión de raíces y el 1,07 % tenían tres raíces. El 22,3 % de los primeros premolares maxilares presentaban curvatura mesial, el 41,9 % presentaban curvatura distal y el 35,7 % no presentaban curvatura alguna; y la configuración más prevalente en primeros premolares maxilares fue el Tipo V. El 88,9 % de los segundos premolares maxilares tenían una sola raíz, el 3,9 % dos raíces, el 6,9 % fusión de raíces y el 0,11 % tres raíces; El 37,59 % de los segundos premolares maxilares presentaban curvatura mesial y el 62,40 % curvatura distal y la configuración más prevalente en segundos premolares maxilares fue el Tipo I. La anatomía del sistema de canales radiculares es extremadamente compleja y tiene muchas configuraciones anatómicas, estas situaciones clínicas deben ser consideradas antes de realizar cualquier tratamiento de endodoncia.

Nanosilver gel as an endodontic alternative against Enterococcus faecalis in an in vitro root canal system in Mexican dental specimens.

Nanotechnology has become a research area with promising results for technological innovation. Endodontics can benefit from this field of research by increasing the success rate of the treatment, which currently ranges between 86% and 98% and has varied very little over the years. One of the causes of endodontic treatment failure is based on the presence of Enterococcus faecalis. The objective of this investigation is to evaluate the antibacterial effect of a gel preparation containing silver nanoparticles (Ag-NP) against E. faecalis present in the walls of the root canal. 60 extracted human uniradicular teeth that were instrumented with Wave One Gold (Denstplay/USA) and subsequently contaminated with Enterococcus faecalis. For antibacterial evaluation, intra-canal conducting was placed, and several groups were formed: a) Ag-NP 300 ug/MI gel; b) Ag-NP 500 ug/MI gel; c) Ca (OH) 2 (Ultracal from Ultradent/USA) and the control group. They were incubated at 37°C and a sample was taken every 24 h for 7 days. The Ag-NP gel showed antimicrobial activity against E. faecalis with a value of minimum inhibitory concentration and minimum bactericidal concentration of 300 g/ml and 900 g/ml, respectively. When the Ag-NP gel was used as an intra-canal conducting drug in an in-vitro model, its antimicrobial effect at 300 g/ml and 500 g/ml was equivalent to the action of Ca(OH)2.

Ability of Three Endodontic Sealers to Fill the Root Canal System in Association with Gutta-Percha.

INTRODUCTION: The present study compared the ability of the endodontic sealers AH Plus, Pulp Canal Sealer and EndoREZ to fill the root canal system in association with gutta-percha. METHODS: Ninety mandibular premolars were accessed, prepared and divided into three groups of 30 teeth each, according to the sealer used to fill the canals: AH Plus, Pulp Canal Sealer and EndoREZ. All the teeth were filled using the continuous wave of condensation technique. The specimens were then decalcified, dehydrated, rendered transparent, and analyzed by three independent evaluators with 8x magnification. Chi-squared test (χ(2), p < 0.05) was used to compare the groups in relation to the totally filled, the partially filled and the non filled ramifications. The same test was used to compare the directions of filled ramifications and the number of ramifications among the three thirds of the roots. RESULTS: EndoREZ filled a significantly higher number of ramifications than AH Plus and Pulp Canal Sealer (χ(2), p < 0.05). All the groups showed higher number of totally filled ramifications than partially filled and unfilled ramifications. The ramifications were more frequently detected in the apical third, followed by medium and coronal thirds, respectively (χ(2), p < 0.05). The ramifications were more frequently detected towards lingual direction (χ(2), p < 0.05). CONCLUSION: EndoREZ presented higher ability to fill the root canal system in association with gutta-percha when compared to AH Plus and Pulp Canal Sealer. The ramifications were more frequently detected in the apical third, running in a lingual direction.

Cleaning Effectiveness of a Reciprocating Single-file and a Conventional Rotary Instrumentation System.

OBJECTIVE: To compare cleaning effectiveness by histological analysis of a reciprocating single-file system with ProTaper rotary instruments during the preparation of curved root canals in extracted teeth. METHODS: A total of 40 root canals with curvatures ranging between 20 - 40 degrees were divided into two groups of 20 canals. Canals were prepared to the following apical sizes: Reciproc size 25 (n=20); ProTaper: F2 (n=20). The normal distribution of data was tested by the Kolmogorov-Smirnov test and the values obtained for the test (Mann-Whitney U test, P < .05) were statistically analyzed using the GraphPad InStat for the Mac OS software (GraphPad Software, La Jolla, CA, USA). RESULTS: There were no significant differences in remaining debris (P > .05) between the two groups. CONCLUSION: The application of reciprocating motion during instrumentation did not result in increased debris when compared with continuous rotation motion, even in the apical part of curved canals. Both instruments resulted in debris in the canal lumen, irrespective of the movement kinematics applied.

Assessment of Mesial Root Morphology and Frequency of MB2 Canals in Maxillary Molars using Cone Beam Computed Tomography / Determinación de la Morfología de la Raíz Mesial y la Frecuencia del Canal MB2 en Molares Maxilares usando Tomografía Computadorizada de Haz Cónico

The aim of this study was to assess the morphology of the mesial root canal system of maxillary molars and the frequency of MB2 canals using cone-beam computed tomography (CBCT). A total of 1374 teeth, first maxillary (1MS, n= 802) and second maxillary molars (2SM, n= 572) of 508 Chilean patients between 8 to 77 years were evaluated through CBCT. The mesiobuccal root was evaluated in all three thirds. Root canal morphology was classified according to Vertucci's method. Data were analyzed by Pearson's Chi-square and Cuzick trend tests. MB2 canal frequency in 1MS was 73.44% and in 2MS 42.48%. The most frequent morphology in 1MS and 2MS were Vertucci type II and I, respectively. No statistically significant association was found between frequencies and side or according to gender (P>0.05). A positive association was found as the age increased in both 1MS and 2MS (P<0.001 and P= 0.023, respectively). Given the anatomical complexity of the mesiobuccal root and the frequent presence of the MB2 canal, the clinician must assume the existence of two canals in this root. CBCT scanning is a good way to initially identify this canal in the different root thirds.

Determinar la morfología del sistema de canales de la raíz mesial de molares maxilares y la frecuencia del canal MB2 usando tomografía computadorizada de haz cónico (TCHC). Un total de 1374 dientes, primeros molares maxilares (1MS, n= 802) y segundos molares maxilares (2MS, n= 572) de 508 pacientes Chilenos entre 8 y 77 años fueron evaluados a través de la TCHC. Se evaluó la raíz mesiobucal en todos sus tercio. La clasificación de Vertucci fue utilizada para determinar la morfología del sistema de canales. Los datos fueron analizados con los test Chi-Cuadrado de Pearson y la prueba de tendencia de Cuzick. La frecuencia del canal MB2 para el 1MS fue 73,44% y el 2MS 42,48%. La morfología mas frecuente en el 1MS y 2MS fueron el tipo II y I de Vertucci, respectivamente. No se encontró asociación significativa entre la frecuencia y el lado o sexo (p>0,005). Una asociación positive fue encontrada a medida que aumentaba la edad en ambos 1MS y 2MS (p<0,001 y p= 0,023, respectivamente). Dada la complejidad de la anatomía de la raíz mesiobucal y la frecuente presencia del canal MB2, el clínico debe asumir la existencia de dos canales en esta raíz. La TCHC es una buena manera de identificar tempranamente el canal en los diferentes tercio radiculares.

Morphology of Mesiobuccal Root Canals of Maxillary First Molars: a comparison of CBCT scanning and Cross-sectioning

Abstract: The aim of this study was to evaluate the mesiobuccal root of maxillary first molars, according to the root canal configuration, prevalence and location of isthmuses at 3 and 6 mm from the apex, comparing cone-beam computed tomography (CBCT) analysis and cross sectioning of roots by thirds. Images of the mesiobuccal root of 100 maxillary first molars were acquired by CBCT and then roots were cross-sectioned into two parts, starting at 3 mm from the apex. Data were recorded and analyzed according to Weine's classification for root canal configuration, and Hsu and Kim's classification for isthmuses. In the analysis of CBCT images, 8 root canals were classified as type I, 57 as type II, 35 as type III. In the cross-sectioning technique, 19 root canals were classified as type I, 60 as type II, 20 as type III and 1 as type IV. The classification of isthmuses was predominantly type I in both CBCT and cross-sectioning evaluations for sections at 3 mm from the apex, while for sections at 6 mm from the apex, the classification of isthmuses was predominantly types V and II in CBCT and cross-sectioning evaluations, respectively. The cross-sectioning technique showed better results in detection of the internal morphology of root canals than CBCT scanning.

Resumo: O objetivo do presente estudo foi avaliar a raiz mésio-vestibular de primeiros molares superiores, de acordo com a configuração do canal radicular e com a prevalência e localização de istmos a 3 e a 6 mm do ápice, comparando a análise realizada em tomografia computadorizada de feixe cônico (TCFC) com a técnica de seccionamento transversal por terços. Foram obtidas imagens tomográficas das raízes mésio-vestibulares de 100 primeiros molares superiores, e em seguida, as raízes foram seccionadas em dois segmentos, iniciando nos 3 mm a partir do ápice. Os dados foram analisados de acordo com a classificação de Weine para configuração de canais radiculares, e de acordo com a classificação de Hsu e Kim para avaliação dos istmos. Na análise das imagens das TCFCs, 8 canais radiculares foram classificados como tipo I, 57 como tipo II, e 35 como tipo III. Na técnica de seccionamento transversal, 19 canais radiculares foram classificados como tipo I, 60 como tipo II, 20 como tipo III, e 1 como tipo IV. Na avaliação dos istmos, houve predominância do tipo I tanto na TCFC quanto na técnica de seccionamento transversal a 3 mm do ápice. Entretanto, a 6 mm do ápice, a classificação dos istmos foi predominantemente tipo V e II, na avaliação em TCFC e na técnica de seccionamento transversal, respectivamente. A técnica de seccionamento transversal demonstrou melhores resultados na detecção da morfologia interna dos canais radiculares avaliados do que a TCFC.

Comparison of two different methods of average working length determination in second molars and premolars / Comparación de dos métodos para determinar la longitud de trabajo promedio en segundos molares y premolares

Within the procedures involved in a successful endodontic treatment is the working length (WL) determination. The root canal end must be detected accurately, and a precise control of the WL must be maintained. There are several methods to determine WL. Researchers have published the average teeth length (ATL) to the human permanent dentition. These measurements are used as an anatomical reference. If the WL is evaluated using a radiographic image, it is accepted as clinical success if the limit of the canal sealing is 1 mm coronal to the root apex. One method to determine WL is based in substract 1 mm to ATL. Another method widely used, assert to achieve a more precise WL determination, through the use of an electronic apex locator (AL). Nevertheless, published measures of ATL are still used as anatomical reference, and are used to determine WL in the absence of an AL. The aim of this study was to determine the average WL of second molars and premolars with endodontic treatment indication using a PropexII® AL, and compare these measurements to WL determination using ATL method. A descriptive cross-sectional study with a non-random sample of consecutive cases was executed. Results showed that there were no statistically significant differences between the WL obtained with AL and ATL method in studied teeth, except mesio-buccal canal of second maxillary molars (19.94 mm average using AL, 1.54 mm greater than ATL method 18.40 mm; p= 0.002). The ATL method to determine WL could be used to determine the WL of second molars and premolars in studied population. Further research should be performed to determine if ATL method is safe and reliable to be used in absence of an AL or in patients where this instrument cannot be used.

Entre los procedimientos involucrados en un tratamiento endodóntico exitoso está la determinación de longitud de trabajo (LT). Esta debe mantenerse durante todo el tratamiento, y el extremo del canal radicular (CR) debe detectarse con precisión. Existen varios métodos para determinar LT; los investigadores han publicado la longitud total promedio (LTP) de la dentición permanente humana. Estas mediciones se utilizan como referencia anatómica. Si LT se evalúa usando una imagen radiográfica, se acepta como éxito clínico cuando el límite de la obturación radicular queda 1 mm coronal al ápice radicular. Un método para determinar LT se basa en restar 1 mm a la LTP. Otro método, que permite una determinación de LT más precisa, se realiza utilizando un localizador apical electrónico (LA). Pese a esto último, las medidas publicadas de LTP todavía se utilizan como referencia anatómica, para determinar LT en ausencia de un LA. El objetivo fue determinar LT promedio de los CR de segundos molares y premolares con indicación de endodoncia utilizando LA PropexII®, y comparar estas mediciones con la LT determinada utilizando el método de LTP. Se realizó un estudio descriptivo de corte transversal con una muestra no probabilística de casos consecutivos. No hubo diferencias estadísticamente significativas entre la LT obtenida con LA y el método LTP en los dientes estudiados, salvo en los canales mesio-bucales de segundos molares superiores (19,94mm promedio usando LA, 1,54 mm mayor que el método LTP: 18,40 mm; p= 0,002). El método para definir LT a través de LTP podría utilizarse para determinar LT de segundos molares y premolares en la población estudiada. Se requieren investigaciones posteriores para determinar si el método que utiliza LTP es confiable para ser utilizado en ausencia de un LA o en pacientes en los que este instrumento no pueda ocuparse.

Morphologic micro-computed tomography analysis of mandibular premolars with three root canals.

INTRODUCTION: This study aimed to describe the anatomy of mandibular premolars with type IX canal configuration by using micro-computed tomography. METHODS: Mandibular premolars with radicular grooves (n = 105) were scanned, and 16 teeth with type IX configuration were selected. Number and location of canals, distances between anatomic landmarks, occurrence of apical delta, root canal fusion, and furcation canals, as well as 2-dimensional (area, perimeter, roundness, major and minor diameters) and 3-dimensional (volume, surface area, and structure model index) analysis were performed. Data were statistically compared by using analysis of variance and Kruskal-Wallis tests (α = 0.05). RESULTS: Overall, specimens had 1 root with a main canal that divided into mesiobuccal, distobuccal, and lingual canals at the furcation level. Mean length of the teeth was 22.9 ± 2.06 mm, and the configuration of the pulp chamber was mostly triangle-shaped. Mean distances from the furcation to the apex and cementoenamel junction were 9.14 ± 2.07 and 5.59 ± 2.19 mm, respectively. Apical delta, root canal fusion, and furcation canals were present in 4, 5, and 10 specimens, respectively. No statistical differences were found in the 2-dimensional and 3-dimensional analyses between root canals (P > .05). CONCLUSIONS: Type IX configuration of the root canal system was found in 16 of 105 mandibular premolars with radicular grooves. Most of the specimens had a triangle-shaped pulp chamber. Within this anatomic configuration, complexities of the root canal systems such as the presence of furcation canals, fusion of canals, oval-shaped canals in the apical third, small orifices at the pulp chamber level, and apical delta were also observed.

A case of unusual anatomy in second mandibular molar with four canals.

Success in root canal treatment is achieved after thought cleaning and shaping followed by the complete obturation of root canal system. Such treatment may be performed in root canal systems that do not comply with the normal anatomical features described in standard textbooks. This article describes the conventional root canal treatment on an unusual mandibular second molar with four root-canals.

Análise radiográfica da trajetória do quarto canal no primeiro molar superior / Radriographic analysis of the trajectory of the fourth canal in first maxillary molar

O objetivo deste trabalho foi avaliar radiograficamente a trajetória do canal mesiopalatino em primeiros molares superiores, visando verificar a importância da análise radiográfica no tratamento desse grupo de dentes, tendo em vista a grande incidência de dois canais na raiz mesiovestibular. Foram utilizados neste estudo 65 primeiros molares superiores extraídos, doados por alunos da PUC/PR. Os dentes foram radiografados com películas radiográficas periapicais, com 20 graus de angulação na incidência disto-excêntrica e com posicionamento de limas tipo K nº 10 nos canais. A análise buscou distribuir a amostra de acordo com a classificação do sistema de canais radiculares proposta por Weine [7]. O resultado obtido foi: 47,7% (31) do tipo I; 21,5% (14) do tipo II; 12,3% (8) do tipo III; 18,5% (12) calcificados. Pode-se concluir que a análise cuidadosa da raiz mesiovestibular é importante para que se possa assegurar um bom prognóstico ao tratamento

The purpose of this study was to evaluate, by radiographic exam, the trajectory of the mesiopalatal canal in maxillary first molars, aiming at assessing the importance of the radiographic analysis in the treatment of these teeth; due to great incidence of two canals in the mesiovestibular root. Sixty-five extracted maxillary first molars were donated by students of PUC/PR and used in this study. Periapical radiographs of the teeth were taken at 20 degrees in the disto-eccentric incidence and positioning #10 K-type files into the canals. The analysis aimed at distributing the sample according to the classification of root canal system proposed by Weine [7]. The obtained result was: 47.7% (31) ­ type I; 21.5% (14) ­ type II; 12.3% (08) ­ type III and 18.5% (12) ­ calcified. It can be concluded that a careful analysis of the mesiovestibular root is important to guarantee a good prognostic of the treatment

Partial characterization of antagonistic substance produced by a Clostridium butyricum strain

The production of antagonistic substance by bacterium present in the infected root canal system (RCS) probably is an important ecological factor for its successful colonization of the local. The objective of this study was to partially characterize an antagonistic substance produced by a Clostridium butyricum isolated from infected RCS.Production of inhibitory compound was evaluated by the agar double layer diffusion technique using Fusobacterium nucleatum and Bifidobacterium adolescentis as indicator bacteria. The physicochemical and biochemical factors tested for the partial characterization were influence of pH and temperature and susceptibility to the action of some proteolytic enzymes. An inhibition zone was observed against the two indicator strains and acidity and bacteriophage were rejected as responsible for this phenomenon. The inhibitory activity showed to be decreasing in a pH range from 3.5 to 6.5 and being stable at temperatures of 60º, 70º and 100ºC, but completely inactivated when exposed at 121ºC. The antagonistic activity was resistant to the proteolytic action of trypsin, a-chymotrypsin and papain. An antagonistic substance was produced by C. butyricum, which was thermo-resistant and probably of non-protein nature.

A produção de substâncias antagonistas por espécies bacterianas presentes em sistema de canais radiculares (SCR) infectados, tem um papel importante na colonização deste sítio. O objetivo deste estudo foi caracterizar parcialmente a substância antagonista produzida por amostra de Clostridium butyricum isolado de SCR infectados.A produção de substância antagonista foi avaliada pela técnica de difusão em ágar utilizando como bactérias indicadoras Fusobacterium nucleatum e Bifidobacterium adolescentis. Os parâmetros físico-químicos utilizados durante a caracterização parcial foram: pH, estabilidade térmica, susceptibilidade à ação das enzimas tripsina, a-quimiotripsina e papaína. Foi observada zona de inibição contra as duas amostras indicadoras e ainda foi demonstrado que ácidos e bacteriófagos não eram responsáveis por este fenômeno. A atividade inibitória mostrou-se diminuída em uma faixa de pH de 3.5 a 6.5 e estável em temperaturas de 60º, 70º e 100ºC, sendo completamente inativada quando exposta a 121ºC. A atividade antagonista foi resistente à ação das enzimas proteolíticas: tripsina, a-quimiotripsina e papaína. A substância antagonista produzida por C. butyricum é termoresistente e provavelmente de natureza não protéica.