Interradicular Canals in 213 Mandibular and 235 Maxillary Molars by Means of Micro-computed Tomographic Analysis: An Ex Vivo Study.

INTRODUCTION: Bacteria and/or toxin residuals in the furcation areas of mandibular and maxillary molars can be the cause of persistent periapical tissue inflammation before or after an endodontic treatment. METHODS: The objective of this ex vivo study was to investigate the frequency of interradicular canals and diverticula in first and second mandibular and first and second maxillary molars by means of micro-computed tomographic imaging. Five hundred thirteen extracted molars, 211 mandibular molars and 302 maxillary molars, were included in this investigation. The area between the pulp chamber floor (PCF) and the furcation area was examined, and the data obtained were evaluated with imaging software that generated the corresponding 3-dimensional images. The results were analyzed by means of descriptive statistics. RESULTS: Interradicular canals were observed in 2.8% and 0.3% of the mandibular and maxillary molars, respectively. The diverticula (blind-ended interradicular canals) originated either at the furcation area or at the PCF. The diverticula frequency observed in mandibular molars was 3.3% (PCF) and 4.3% (bifurcation). The maxillary molar diverticula frequency observed was 2.0% (trifurcation), with none of them originating at the PCF. Altogether (n = 513) diverticula originated more frequently from the PCF (59.1%) than from the furcation area (40.9%). CONCLUSIONS: Although interradicular canals as well as diverticula were observed in a relatively small number of the investigated molars, practitioners should always be aware of their existence because without an adequate chemical debridement/disinfection of the pulp chamber root canal system, successful endodontic treatment could be compromised in up to 10% of the cases.

Root Canal Morphology and Configuration of the Mandibular Canine: A Systematic Review.

The aim of this study was to systematically review the root canal morphology and configuration (RCC) of mandibular canines (MaCa). The review was registered in the PROSPERO database (ID-272297) and it was carried out following the PRISMA guidelines. Three electronic databases (MEDLINE via PubMed, Embase, Scopus) were searched. Randomized controlled trials, cross-sectional, cohort, comparative, evaluation and validation studies have been included. The anatomical quality assessment (AQUA) tool was used for a quality assessment of the anatomical studies. Of 910 studies retrieved from the systematic search, 28 studies investigating RCCs were included. Most MaCa were single-rooted (87.9-100%), while two-rooted MaCa were present up to 12.1%. The 1-1-1/1 (35.8-96.4%) was the most commonly reported RCC, followed by 2-2-1/1 (0.2-22.0%) and 1-2-1/1 (0.9-20.0%). A high frequency of 1-1-1/1 RCC in MaCa has been described. Most systematic review reports confirm that two-rooted MaCa are found considerably less frequently than single-rooted ones.

Internal morphology of 101 mandibular canines of a Swiss-German population by means of micro-CT: An ex vivo study.

The aim of this study was to investigate the root canal system morphology by means of a root canal configuration (RCC) classification described with a four-digit system, the physiological foramen geometry and accessory canal frequency and morphology, of 101 mandibular canines (MaCa) of a Swiss-German population by means of micro-computed tomography. Micro-CT examination of the MaCa was performed and the obtained images analyzed with a 3D imaging software. In single-rooted MaCas, the most frequently observed RCCs were 1-1-1/1 (74.5%) and 1-1-1/2 (14.3%). Seven other RCCs were less frequently observed with a frequency from 4.1 to 1.0%. One physiological foramen was observed in 80.6% of the MaCas, two in 16.3%, three in 1.0% and four in 2.0%. Accessory and connecting canals were apparent only in the middle and apical root thirds. Two-rooted MaCas occurred less frequently (n = 3). When one physiological foramen was present, the mean size of the narrow and wide diameters were 0.28 mm (± 0.07) and 0.40 mm (± 0.11), while the distance between physiological and anatomical foramen was 0.45 mm (± 0.17). MaCas are predominantly single-rooted teeth with a 1-1-1/1 or 1-1-1/2 RCC. Most MaCas had one physiological foramen with an oval shape.