Morphology of the Second Mesiobuccal Canal in the Maxillary Second Molar / Morfología del Segundo Canal Mesiovestibular en el Segundo Molar Maxilar

SUMMARY: Failure to locate a complete canal system affects the prognosis of root canal treatment. A missed root canal is one of the most common reasons for failed root canal treatment. The prevalence of the second mesiobuccal canal in the maxillary second molar is relatively high and has a variety of configurations. Therefore, knowledge of its morphology is required in clinical endodontics. This review presented the canal in terms of its prevalence, classification, anatomical features, and the method for locating the second mesiobuccal canal in the maxillary second molar. Root canal treatment requires knowledge of tooth morphology, appropriate access preparation, and a thorough examination of the tooth's interior. Thus, clinicians should carefully employ various methods for assessing the anatomy of the entire root canal system to prevent failure in locating the second mesiobuccal canal. This canal can be located by modifying the access cavity design and utilizing specific instruments to improve the second mesiobuccal canal system visualization.

La falta de localización de un sistema completo de canal afecta el pronóstico del tratamiento de éste. La omisión de un tratamiento de canal es uno de los motivos más frecuentes por las que el tratamiento de canal fracasa. La prevalencia del segundo canal mesiovestibular en el segundo molar superior es relativamente alta y tiene una variedad de configuraciones. Por tanto, el conocimiento de su morfología es necesario en endodoncia clínica. Esta revisión presentó el canal en términos de su prevalencia, clasificación, características anatómicas y el método para localizar el segundo canal mesiovestibular en el segundo molar superior. El tratamiento de canal requiere conocimiento de la morfología del diente, una preparación adecuada del acceso y un examen exhaustivo del interior del diente. Por lo tanto, los dentistas deben emplear cuidadosamente varios métodos para evaluar la anatomía de todo el sistema de canales radiculares para evitar fallas en la localización del segundo canal mesiovestibular. Este canal se puede localizar modificando el diseño de la cavidad de acceso y utilizando instrumentos específicos para mejorar la visualización del sistema del segundo canal mesiovestibular.

Canal mesiovestibular 2 (MV2): como vencer as dificuldades durante seu tratamento / Second mesiobuccal canal (MB2): how to overcome the difficulties in treating it

Os canais radiculares, quando não tratados, podem ter um impacto direto na previsibilidade do tratamento endodôntico. Hoje, já se sabe que o canal mesiovestibular 2 (MV2) é o mais esquecido sem tratamento durante a terapia endodôntica e, quando isso acontece, a probabilidade de aparecimento de doença inflamatória na região periapical é de 4,5 a 6,5 vezes maior do que em dentes que tiveram todos os canais tratados. Sendo assim, o clínico deve conhecer informações importantes relacionadas às complexidades anatômicas que dificultam o acesso e exploração desse canal, bem como conhecer manobras que facilitam o seu tratamento, uma vez que localizar e negociar o MV2 sempre foi um grande desafio. O objetivo do presente estudo é mostrar os principais obstáculos enfrentados para localizar e tratar o canal MV2, e orientar como essas dificuldades podem ser superadas no dia a dia da clínica endodôntica (AU).

When not treated, root canals may affect the predictability of endodontic treatments directly. The second mesiobuccal root canal (2MB) is the canal most often missed and left untreated during endodontic treatments. The probability of inflammatory disease in the periapical region in these cases is 4.5 to 6.5 times greater than in teeth that have all canals treated. Therefore, clinical dentists should know the anatomical complexities that may complicate root canal access and exploration. As 2MB detection and negotiation are a great challenge, they should also be familiar with the procedures that facilitate treatment. This study describes the main obstacles to the location and treatment of the 2MB canal and discusses how these obstacles may be overcome in routine endodontic practice (AU).

Prevalence and location of the secondary mesiobuccal canal in 1,100 maxillary molars using cone beam computed tomography.

BACKGROUND: Several articles have used cone beam computed tomography (CBCT) to study the morphology of the maxillary molars and to ascertain its ability to visualize the second mesiobuccal canal (MB2); however, its geometric location has not been examined in depth. The aim of this study was to describe in vivo the prevalence and location of the MB2 in the mesiobuccal root of the first maxillary molar (1MM) and the second maxillary molar (2MM) through CBCT imaging. METHODS: Five hundred fifty CBCT images of the 1MM and 550 of the 2MM were analyzed. To detect the MB2 canal, the observation and measurements were done 1 mm apically to the pulpal floor to standardize the methodology. The geometric location of the central point of the MB2 canal (PMB2) was measured in relation to the central point of the mesiobuccal canal (PMB1) and in relation to the line projected between the PMB1 and the central point of the palatal canals (PP). The data were analyzed using descriptive statistics, with a value of P < 0.05 being statistically significant. RESULTS: In the 1MM, the prevalence of the MB2 canal was 69.82% and was more frequent in women (p = 0.005). The distance between PMB1 and PP was 7.64 ± 1.04 mm. The average distance between PMB1 and PMB2 was 2.68 ± 0.49 mm, and for PMB2 and the line projected between the PMB1 and PP canals was 1.25 ± 0.34 mm. In the 2MM, the MB2 canal was identified in 46.91% and was more frequent in men (p = 0.000). The distance between PMB1 and PP was 7.02 ± 1.30. The average distance between PMB1 and PMB2 was 2.41 ± 0.64 mm, and for the PMB2 and the line projected between the PMB1 and PP canals was 0.98 ± 0.33 mm. CONCLUSIONS: The MB2 canal was found in a high percentage of the sample. These results indicate that CBCT is an effective, high-precision diagnostic tool not only for detecting but also locating in vivo the MB2 canal in the mesiobuccal root of upper molars.

Negotiability of Second Mesiobuccal Canals in Maxillary Molars Using a Reciprocating System.

The aim of this prospective case series report was to assess the frequency in which the Reciproc R25 instrument (VDW, Munich, Germany) is able to scout and reach the full working length (WL) in second mesiobuccal (MB2) canals from maxillary molars. Conventional hand file negotiation was used as the reference technique for comparison. Maxillary molars (270 first molars and 71 second molars) were included in this study. After local anesthesia, the tooth was isolated with a rubber dam, and traditional straight-line access was made. After locating both first mesiobuccal and MB2 canals, patients were randomly assigned to one of the experimental groups (conventional hand filing preparation or R25 Reciproc preparation). All cases in which the hand files (G1) and R25 instrument (G2) were able to reach the fully electronically determined WL were classified as "reaching full WL" (RFWL). All cases in which the hand files (G1) and R25 instrument (G2) were unable to negotiate the full-length canal were classified as "not reaching full WL" (NRFWL). The number of root canals classified as RFWL and NRFWL from both groups were recorded and tabulated on an Excel data sheet (Microsoft, Redmond, WA). The frequency distributions (%) of root canals classified as RFWL and NRFWL were compared with overall-treated canals and for each treatment approach (hand file and R25 instrument) using a Pearson chi-square test. In group 1, the hand file approach reached the full WL in 57.48% of cases, whereas in group 2 the R25 instrument reached the full WL in 85.63% of cases. Three file separations occurred in each group while negotiating the MB2 canal. According to this study, the R25 instrument was 32% more effective when compared with hand files in scouting and negotiating MB2 canals in maxillary first and second molars. There was no difference with regard to file separation when comparing both preparation techniques.

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.

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.