Frecuencia y tipología del segundo conducto mesiovestibular en primeros molares superiores / Frequency and typology of the second mesiobuccal canal in maxillary first molars

Objetivos: Evaluar mediante microscopia quirúrgica la presencia del segundo conducto mesiovestibular (MV2) en el piso de la cámara pulpar de los primeros molares superiores, determinar su abordabilidad, establecer el calibre de lima que llegó al tercio apical y tipificar radiovisiográficamente su morfología se-gún la clasificación de Weine. Materiales y métodos: Se utilizaron 48 primeros molares superiores huma-nos extraídos. Sé tomaron radiovisografías preope-ratorias (Carestream 5200) en sentido orto radial y mesio-distal. Se realizó apertura y se localizó entra-da del MV2 con microscopio quirúrgico (Newton MEC XXI, Argentina) a 16 x. Se cateterizó MV1 y MV2 con limas tipo K #10 y #15 (Dentsply Maillefer). Se cortó raíz distovestibular para mejorar visualización ra-diovisográfica. Se tomó conductometria en sentido mesio-distal para establecer la tipología. Se compa-raron frecuencias y porcentajes mediante test de Chi-cuadrado con corrección de Yates, prueba exac-ta de Fisher y test z para diferencia de proporcio-nes. Se calcularon intervalos de confianza 95% para porcentajes mediante método score de Wilson. Re-sultados: El 54% (26 casos) presentó MV2. De los 26 MV2, el 77% (20 casos) fueron abordables, porcen-taje significativamente mayor al 23% no abordable (z=3,62; P<0,05). Al hacer cateterismo, hubo asocia-ción significativa entre tipo de conducto (MV1 y MV2) y calibre de lima que llegó al tercio apical (Chi-cua-drado=29,12; gl=1; P<0,05). La tipología I (58%) fue significativamente mayor que las tipologías II (21%) y III (21%) (P<0,05 para ambas comparaciones). Con-clusión: El alto porcentaje de piezas que presentó MV2 evidencia la importancia clínica de detectarlo y tratarlo correctamente. Dado el alto porcentaje de piezas donde fue abordable, se concluye que el clíni-co debe tener conocimiento, destreza y la tecnología necesaria para poder abordarlo. Si bien la tipología I (58%) fue la más encontrada, cuando el MV2 termina en foramen independiente (tipo III), su omisión puede conducir al fracaso del tratamiento (AU))

Objectives: To evaluate by surgical microscopy the presence of second mesiobuccal canal (MB2) in the pulp chamber floor of the maxillary first molars, determine its approachability, establish the caliber of the file that reached the apical third, and radiographically typify its morphology according to Weine ́s classification. Materials and methods: 48 extracted human maxillary first molars were used. Preoperative radiovisographies (Carestream 5200) were taken in ortho-radial and mesio-distal direction. Coronal access was made and the entrance of MB2 was located with a surgical microscope (Newton MEC XXI, Argentina) at 16x. MB1 and MB2 were catheterized with K files #10 and #15 (Dentsply Maillefer). Distobuccal root was cut to improve radiovisographic visualization. Conductometry was taken in mesio-distal direction to establish the typology. Frequencies and percentages were compared using Chi-square test with Yates correction, Fisher's exact test and z test for difference in proportions. 95% confidence intervals were calculated for percentages using Wilson score method. Results: 54% (26 cases) presented MB2. Of the 26 MB2, 77% (20 cases) were approachable, a significantly higher percentage than those not approachable (z=3.62; P<0.05). When performing catheterization, there was a significant association between type of canal (MB1 and MB2) and file caliber that reached the apical third (Chi-square=29.12; df=1; P<0.05). Typology I (58%) was significantly higher than typologies II (21%) and III (21%) (P<0.05 for both comparisons). Conclusion: The high percentage of specimens that showed MB2 evidence the clinical importance of detecting and treating it correctly. Given the percentage of pieces where it was approachable (77%), it is concluded that the clinician must have the knowledge, skill and necessary technology to be able to approach it. Although typology I (58%) was the most found, when MB2 ends an independent foramen (type III), its omission can lead to treatment failure (AU)

Influence of age and experience with magnification on locating the second mesiobuccal canal in maxillary first molars: A preliminary study.

The aim was to evaluate the effectiveness of clinical methods in identifying the presence of second mesiobuccal canal in maxillary first molars. The influence of age and experience with microscopy was also assessed. Sixty six teeth were selected and the mesiobuccal canal was confirmed in all of the samples by Cone-Beam Computed Tomography. After endodontic cavity access, teeth were evaluated through direct visual; dental loupe and operating microscope. None of the methods was successful in finding the mesiobuccal canal in all samples. Professionals <40, the magnification did not influence the location. Professionals >40, the magnification significantly influenced the location. In the direct vision, professionals >40 years located fewer canals than those <40 years of age with experience. In conclusion, these preliminary findings showed that when the microscope was used, the professionals with experience, regardless of age, found a higher number of canals. The use of the microscope was significant for professionals >40 years.

Morphological characteristics of the mesiobuccal root in the presence of a second mesiobuccal canal: a micro-CT study.

Objectives: This study investigated the internal morphology of mesiobuccal (MB) roots of maxillary molars with a second mesiobuccal (MB2) canal. Materials and Methods: Forty-seven maxillary first or second molars from Brazilians were scanned using micro-computed tomography. The following measurements were obtained from the MB roots: root thickness, root width, and dentin thickness of the buccal aspect of the first mesiobuccal (MB1) canal, between the MB1 and MB2 canals, and the palatal aspect of the MB2 and MB1 canals at 3 mm from the root apex and in the furcation region. For statistical analysis, the Student's t-test and analysis of variance with the post-hoc Tukey test were used (α = 0.05). Results: In maxillary molars with an MB2 canal, MB roots were significantly thicker (p = 0.0014) and narrower (p = 0.0016) than in maxillary molars without an MB2 canal. The dentin thickness of the palatal aspect of the MB1 canal was also significantly greater than that of MB roots without an MB2 canal at 3 mm from the root apex (p = 0.0007) and in the furcation region (p < 0.0001). In the furcation region of maxillary molars with an MB2 canal, the dentin thickness between the MB1 and MB2 canals was significantly smaller than that in the buccal and palatal aspects (p < 0.0001). Conclusions: The internal morphology of MB roots of maxillary molars with an MB2 canal revealed differences in dentin thickness, root diameter, and distance between the canals when compared with maxillary molars without an MB2 canal.

The MB3 canal in maxillary molars: a micro-CT study.

OBJECTIVES: To assess the internal and external morphologies of the mesiobuccal (MB) root of maxillary molars presenting a third root canal (MB3), using micro-computed tomography (micro-CT). MATERIAL AND METHODS: Two-hundred and sixty-five extracted maxillary first and second molars with different root configurations were imaged in a micro-CT scanner at 19.6-µm pixel size. Sixteen teeth presenting MB3 canal were selected and evaluated regarding root configuration, minimal dentine thickness 2 mm under the furcation area, canal configuration of the MB root, MB3 canal morphology (location, independent or confluent orifice, and anatomy types), and the apical anatomy (aspect ratio, number of accessory canals and foramina, presence of isthmus, and independent MB3 foramen). RESULTS: Overall, a high variability in canal configuration was detected in the MB root. MB3 canal was observed in 10 maxillary first molars and 6 maxillary second molars (n = 16). Minimal dentine thickness related to the MB3 canal at the coronal third was smaller than that of the MB1 canal. A complex internal anatomy comprising 13 different root canal configurations was observed. A high number of independent MB3 orifices at the pulp chamber floor was observed in the first molars (7 out of 10 teeth), while most of the specimens (n = 14) showed a confluent anatomy of the MB3 canal. A varied number of accessory canals and foramina were observed. At the apical third, isthmus could be observed in 6 specimens, while an independent MB3 foramen was present in 37.5% of the MB roots. CONCLUSIONS: MB3 canal is a rare anatomical variation present in maxillary first and second molars. Its presence can be associated to a complex internal anatomy of the MB root which includes the presence of isthmuses and multiple accessory canals and foramina at the apical third, but also a thin dentine thickness at the coronal third and a confluent anatomy of the MB3 with the other main canals.

Second Mesiobuccal Root Canal of Maxillary First Molars in a Brazilian Population in High-Resolution Cone-Beam Computed Tomography.

INTRODUCTION: The second canal of the mesiobuccal root (MB2) of the maxillary first molars (MFM) is difficult to detect in conventional radiographs and can be a major cause of failure in endodontic treatments. The aim of this study was to investigate the prevalence and anatomy of the MB2 by using high-resolution cone-beam computed tomography (CBCT). METHODS AND MATERIALS: Three radiologists examined 414 high-resolution CBCTs. Of these, the CBCTs of 287 patients (mean age 49.43±16.76) who had at least one MFM were selected, making a total of 362 teeth. Prevalence and its relation with gender and age of the patients, side of the tooth, and Vertucci's classification were analyzed. Data were statistically analyzed (P<0.05). RESULTS: A total of 68.23% of the teeth exhibited the MB2. The presence of the MB2 was equivalent in both genders and significantly higher in younger patients. There was no correlation between the presence of the MB2 in relation to both the sides of the MFM and the FOV size. Smaller FOV recognized higher Vertucci's grades. CONCLUSIONS: It was concluded that the prevalence of the MB2 canal in maxillary first molars in this Brazilian population examined with high-resolution CBTCs is 68.23%, being more prevalent in young patients. Gender and the side examined are no factors for determining the presence of MB2. Although the both FOVs of the high-resolution CBTCs (FOV 8 and 5) detect the MB2 canal, smaller FOV (FOV 5) is more accurate in the analysis of the internal anatomy of such root canals, according to the Vertucci´s classification.

Multidimensional Analysis of Curved Root Canal Preparation Using Continuous or Reciprocating Nickel-titanium Instruments.

Objective: To evaluate transportation (T) and centering ability (CA) of root canal preparations using continuous or reciprocating nickel-titanium endodontic files. Materials and Methods: Ninety-six mesiobuccal root canals of mandibular first and second molars were randomly divided into 6 groups (n=16) according to the rotary file used: 1. ProTaper Next; 2. ProTaper Gold; 3. Mtwo; 4. BioRaCe; 5. WaveOne Gold; 6. Reciproc. Root canals were prepared according to manufacturer's instructions. Cone beam computed tomography scans were obtained before and after root canal preparation. Measurements were made at six different reference points: 2, 3 and 4 mm from the apex and 2, 3 and 4 mm below furcation in different directions. Results: The greatest Mesiodistal (MD) Transportation (T) was found for Reciproc files (p<0.05), and the greatest buccolingual (BL) T, for Reciproc, ProTaper Gold and ProTaper Next files (p<0.05). The greatest Mesiodistal (MD) Centering Ability (CA) was found for BioRaCe files (p<0.05), and the greatest Buccolingual (BL) CA, for BioRaCe and Mtwo files (p<0.05). Conclusion: All systems produced root canal transportation. No file system achieved perfect CA of root preparation. Reciproc files had the greatest MD T and BL T. BioRaCe files had the greatest MD CA, whereas BL CA was similar for BioRaCe and Mtwo files.

Evaluación de la frecuencia, ubicación y tipos de itsmos en raíces mesiobucales de primeros molares maxilares: un estudio ex vivo / Evaluation of Isthmus frequency, location, and types in mesiobuccal roots of first maxillary molars: an ex vivo study

El objetivo fue describir la configuración interna del sistema canalicular de la raíz mesiobucal (MB) del primer molar maxilar, identificando el número de canales junto a la frecuencia, ubicación y tipos de itsmo a 1, 3 y 5 mm del ápice. Esta investigación fue aprobado por el comité de ética. Se realizó un estudio descriptivo ex vivo de corte transversal. Molares extraídos fueron limpiados, desinfectados y fijados en formalina al 10 %. Se identificó la raíz MB y se obtuvieron cortes transversales (3) a 1, 3 y 5 mm desde apical a coronal, identificadas como secciones A, B y C. Ciento cincuenta secciones fueron teñidas con azul de metileno y observadas bajo microscopio óptico, tanto en la superficie apical como coronal, y analizadas mediante el programa ImageJ. Se obtuvieron estadísticas descriptivas (media ± DE), y mediante las prueba ANOVA y chi-cuadrado de Pearson se compararon las secciones a diferentes niveles. Se observaron un total de 445 canales radiculares, 289 correspondieron a canales accesorios. El 41,6 % fueron canales mesiobucales secundarios (MB2) y 5,1 % un tercer canal accesorio. Se observaron con mayor frecuencia istmos Tipo I (48), seguidos de Tipo IV (26); los Tipos II, III y V no superaron el 15 %. De acuerdo con la prueba de chi-cuadrado de Pearson, existen diferencias significativas entre los tipos istmos y distancia del ápice (p> 0,001). La incidencia del Tipo I fue mayor cerca del ápice, con un descenso hacia los 3,0 mm. Se observó una compleja morfología del sistema canalicular apical en la raíz MB, que explica su baja tasa de éxito cuando son tratados con endodoncia. Las variaciones anatómicas, tales como MB2 o más canales accesorios e istmos deben ser considerados en la planificación y realización del tratamiento de endodoncia convencional o cirugía apical, con el fin de lograr procedimientos más exitosos. Se recomienda que las apicectomías se extiendan por lo menos a 3,3 mm del ápice.

The aim was to describe the internal configuration of the canalicular system of the mesiobuccal root (MB) of the maxillary first permanent molar, identifying the number of canals and isthmus frequency, location, and types at 1, 3 and 5 mm from the apex. This research was approved by the ethics committee. A descriptive ex vivo cross-sectional study was conducted. Extracted molars were cleaned, disinfected and fixed in 10% buffered formalin. The non-instrumented MB root was identified and 3 cross sections at 1, 3 and 5 mm from apical to coronal identified as A, B and C were obtained. 150 sections were stained with methylene blue and observed under microscope, in both apical and coronal surface using the ImageJ program. Descriptive statistics (Mean±SD) was obtained, and ANOVA and Pearson chi-square tests were used to compare the sections at different levels. A total of 445 root canals were observed, 289 corresponded to accessory canals. 41.6% were secondary mesiobuccal canal (MB2) and 5.1% a third accessory canal. The isthmus observed were Type I (48), followed by Type IV (26); Types II, III and V did not exceed 15%. According to the Pearson chi-square test, there are significant differences between the isthmus types and distance of the apex (p> 0.001). The incidence of Type I was greater near the apex, with a decline towards 3.0 mm. A complex morphology of the apical maxillary MB root system was found, and explains their low success rate when treated endodontically. Anatomical variations such as MB2, accessory canals and isthmus should be considered when planning and conducting endodontic treatment or apical surgery, in order to achieve more successful procedures. It is recommended that apicectomies extend at least 3.3 mm from the apex.

Cone-beam computed tomography study of prevalence and location of MB2 canal in the mesiobuccal root of the maxillary second molar.

The maxillary second molar (2 MM) has the most complex root canal system, and a high percentage of treatment failures is due to the impossibility of locating, instrumenting and obturating the second mesiobuccal canal (MB2). The aim of this study was to describe in vivo the prevalence and location of the MB2 canal in the mesiobuccal root of the permanent maxillary second molar through CBCT image analysis. Two hundred twenty five CBCT images of 2 MM were studied. In the presence of the MB2 canal, the floor of the coronal cavity was located and advanced every 1 mm apically to standardize observation. The geometric location in relation to the primary mesiobuccal (MB1) and palatal (P) canals was done by locating the central points of the canal and projecting a line between them, together with a perpendicular line between MB1-P (point T). The data were analyzed using descriptive statistics, with a value of P < 0.05 being statistically significant. The MB2 canal was identified in 48% of the cases. It was located 2.2 ± 0.54 mm palatally and 0.98 ± 0.35 mesially to the MB1 canal. The average age of the subjects where it was found was 26.36 ± 10.85 years. Its location was more frequent in men (63%), and no differences were observed in its appearance in the hemi-arch. It is necessary to know the high probability of finding the MB2 canal in the maxillary second molar, and the CBCT is a good diagnostic tool for its detection and exploration.

Anatomia interna da raiz mésio-vestibular dos primeiros e segundos molares permanentes superiores / Internal anatomy of the mesiobuccal root of the first and second permanent upper molars

Objetivo: Esta pesquisa refere-se ao estudo da anatomia interna da raiz mésio-vestibular dos primeiros e segundos molares superiores permanentes. Material e método: Duzentos e vinte cinco molares tiveram a sua raiz mésio-vestibular seccionada ao nível amelo-cementário e, visualmente, com auxílio de sonda exploradora, foram selecionadas aquelas que apresentaram na região cervical, dois orifícos correspondentes às entradas dos condutos mésio-vestibular e mésio-palatino, perfazendo um total de cem raízes (44,44 %). Todas elas foram submetidas ao processo de diafanização, associada à injeção de hematoxilina, que confere transparência às raízes e coloração aos condutos, permitindo, assim, a avaliação tridimensional da anatomia dental interna. Resultados: A presença de dois condutos percorrendo toda a raiz e terminando separados em dois forames foi observada em 46% da amostra, sendo que 68% em altura apical distinta e, a percentagem de condutos que se fusionaram nos terços cervical, médio ou apical e terminaram em um forame foi de 53%. Encontrou-se, também, uma raiz com três condutos e oito dentes com uma raiz extra, correspondente ao canal mésio-palatino. Conclusão: Os resultados mostraram que a incidência expressiva de mais de um conduto na raiz mésio-vestibular e o complexo sistema de canais que ela apresenta, pode ter grande influência no sucesso dos tratamentos endodônticos dos molares superiores, exigindo, por isso, atenção especial do endodontista.

Aim: This research concerns the study of the internal anatomy of the mesiobuccal root of the first and second permanent maxillary molars. Material and methods: Two hundred and twenty five molars had their mesiobuccal root sectioned at the amelo-cemental. With the aid of the exploratory probe it was conducted a visual selection of the roots that presented at the cervical region two orifices corresponding to the entries of the mesiobuccal and mesiopalatal conduits. The total amount was of one hundred roots (44,44%). All of them underwent the process of diafanization associated with the injection of hematoxylin, what brings transparency to the roots and coloration to the ducts, thus enabling three-dimensional evaluation of the internal dental anatomy. Results: The presence of two conduits running through the entire root and ending in two separate foramina was observed in 46% of the sample, 68% in distinct apical height. The percentage of the conduits that merged at cervical, middle or apical thirds and ended in a foramen was of 53%. It was also found a root with three conduits and eight teeth with an extra root, corresponding to the mesio-palatal canal. Conclusions: The results showed that the expressive incidence of more than one conduit at the mesiobuccal root and the complex system of canals that it presents can have a great influence on the success of treatments of the upper molars, therefore requiring special attention from the endodontist.