An in vitro assessment of type, position and incidence of isthmus in human permanent molars

Abstract

Root canal anatomical complexities, such as isthmus, may limit the action of the endodontic instruments, irrigant solutions and intracanal medications, leading to endodontic treatment failure.ObjectivesThis in vitro study assessed the type, position and incidence of isthmus in human permanent molars.Material and MethodsOne hundred and twenty eight upper and lower first and second permanent molars were analyzed. The roots were embedded in transparent resin, and then split at different distances from the apex (1.0-2.5-4.0-5.5-7.0 mm). Following the sample examination in stereomicroscope, the data were submitted to chi-square statistical test at a 5% significance level.ResultsThe highest isthmus incidence was at 7.0 mm from the root apex in all samples, except the distal root of lower molars (at 5.5 mm). In upper and lower molars, type V (complete isthmus with a continuous opening between the two main root canals) was the most common classification of isthmus (28.8%). In the mesial root of first and second mandibular molars, type IV had the highest incidence (36% and 23.9%, respectively).ConclusionIt was concluded that isthmus was widely found in flat roots, with a low percentage in areas close to the apex. In upper and lower molars, these structures were most frequently found at 7 mm from the apex.

Internal and external morphology of mandibular molars: An original micro‐CT study and meta‐analysis with review of implications for endodontic therapy

“…The characteristics of included studies are presented in Table . A total of 65 studies ( n = 23,846 teeth), including our original study, were considered eligible and were included in the meta‐analysis (Skidmore and Bjorndal, ; Pineda and Kuttler, ; Reichart and Metah, ; Vertucci, ; Walker and Quackenbush, ; Walker, ; Weine et al, ; Fabra‐Campos, ; Yew and Chan, ; Calişkan et al, ; Prakashchandra and Reddy, ; Kartal and Cimilli, ; Zaatar et al, ; Guerisoli et al, ; Sperber and Moreau, ; al‐Nazhan, ; Sidow et al, ; Gulabivala et al, ; Wasti et al, ; Duda et al, ; Sert and Bayirli, ; Sert et al, ; Zhang et al, ; Jung et al, ; von Arx, ; Ahmed et al, ; Peiris, ; Tu et al, ; Pattanshetti et al, ; Peiris et al, ; Rahimi et al, ; Al‐Qudah and Awawdeh, ; Chen et al, ; Rwenyonyi et al, ; Schäfer et al, ; Gu et al, ; Huang et al, ; Neelakantan et al, ; Wang et al, ; Bahammam and Bahammam, ; Cosić, ; Demirbuga et al, ; Jang et al, ; Silva et al, ; Khan et al, ; Lima et al, ; Caputo et al, ; Celikten et al, ; Kim et al, ; Min et al, ; Monsarrat et al, ; Wolf et al, ; Madani et al, ; Martins et al, ; Mohammadzadeh et al, ; Pawar et al, ; Pekiner et al, ; Pérez‐Heredia et al, ). There were 32 imaging studies, 31 cadaveric studies, and two intraoperative studies.…”

Frequency of Root Canal Isthmi in Human Permanent Teeth Determined by Cone-beam Computed Tomography

“…Numerous methods have been used to evaluate RCIs: periapical radiography, vertical and transversal sectioning, clearing and staining, stereomicroscopy, surgical microscopy, dissecting microscopy, plastic casting, scanning electronic microscopy, CBCT, and MCT (4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(24)(25)(26)(27). CBCT images provide a satisfactory visualization of RCIs, and their use in association with a longitudinal map-reading strategy to identify isthmi seems to yield satisfactory results.…”

“…Several investigations used three-dimensional CBCT images to describe root canal anatomy (9,12,16,19,(23)(24)(25). Studies that used map-reading strategies showed the potential of this CBCT tool (9, 28), which evaluates sequential 0.1-mm/0.1-mm axial slices of each root from the coronal to the apical (or the apical to the coronal) region.…”

Incidencia y Tipo de Istmos en Primeros Molares Permanentes Humanos, Evaluación in vitro

“…En este trabajo, se encontró una alta cantidad de istmos en la raíz mesiovestibular del primer molar superior a una distancia de 3-7 mm desde el ápice, lo cual concuerda con Lima et al (2014) y Tam & Yu (2002). Del mismo modo la raíz mesial del molar inferior mostró una prevalencia muy alta de istmo desde los 3 hasta los 7 mm desde el ápice llegando hasta un 100 % en el segmento 4 coincidiendo con los hallazgos de Gu et al (2009).…”