Evaluation of apical foramen distance in relation to the anatomical apex of mandibular molars by cone-beam computed tomography (CBCT) in a selected Iranian population

Introduction: Knowledge of the internal anatomy and apical foramen of a tooth has always been a fundamental prerequisite for root canal therapy. Aim of the present study was to evaluate the distance of apical foramen in relation to the anatomical apex of mandibular molars by cone beam computed tomography (CBCT) in a selected Iranian population. Material & Methods: In this cross- sectional study, 97 CBCT images of 25-50 years old patients were evaluated .the teeth were assessed in coronal plan. Results: Average (±SD) distance from apical foramen to the anatomical apex in the mesio-buccal and mesio-lingual, distal canal were [0.938 (±0.294)mm], [0.964 (±0.315)mm] and [0.982 (±0.322)mm] respectively. No statistical difference was found between right and left quadrant. Conclusion: This study demonstrated that 1mm distance from radiographic apex in mandibular molars could be appropriate for root canal therapy

Root Canal Morphology of Mandibular Canine in an Iranian Population: A CBCT Assessment

Introduction: The present study was conducted to assess the morphology of mandibular canines using cone-beam computed tomography (CBCT) in a north Iranian population. Methods and Materials: For the morphological assessment of mandibular canines, 150 CBCT images taken from patients for different reasons were used. The mandibular canines were examined in sagittal, coronal and axial dimensions. The canal pattern, number of roots/canals, the tooth length, the orientation of the roots and the position of the apical foramina were evaluated and the effect of gender on each variable was assessed. The obtained data were analyzed using the Chi-square and student’s t-tests. Results: According to the Vertucci’s criteria, the most common pattern was type I morphology (89.7%), followed by types III (5.7%), II (3.7%) and V (1%). No significant differences were observed between the male and female patients in terms of canal type (P>0.05). Gender difference is a factor which affected the root length and the number of mandibular canine root and root canal. There were 296 single-root and four double-root canines. The double-root canines and mandibular canine with two canals were significantly more common among men than women (P=0.00). The apical foramen was laterally positioned in 68.3% and centrally in 31.7% of the cases, and the root curvatures were mostly oriented toward the buccal region. No significant statistical difference was observed for mentioned parameters in right and left half of the jaw. Conclusion: Due the diverse morphology and the potential presence of a second mandibular canine among Iranians, dentists should perform endodontic treatments with greater care. CBCT is an accurate tool for the morphological assessment of root canals.Keywords: Canine; Cone-Beam Computed Tomography; Root Canal

Diagnostic Accuracy of Cone-Beam Computed Tomography and Periapical Radiography in Internal Root Resorption

Introduction: The aim of this study was to compare the diagnostic value of cone-beam computed tomography (CBCT) and periapical (PA) radiography in detecting internal root resorption. Methods and Materials: Eighty single rooted human teeth with visible pulps in PA radiography were split mesiodistally along the coronal plane. Internal resorption like lesions were created in three areas (cervical, middle and apical) in labial wall of the canals in different diameters. PA radiography and CBCT images were taken from each tooth. Two observers examined the radiographs and CBCT images to evaluate the presence of resorption cavities. The data were statistically analyzed and degree of agreement was calculated using Cohen’s kappa (k) values. Results: The mean±SD of agreement coefficient of kappa between the two observers of the CBCT images was calculated to be 0.681±0.047. The coefficients for the direct, mesial and distal PA radiography were 0.405±0.059, 0.421±0.060 and 0.432±0.056, respectively (P=0.001). The differences in the diagnostic accuracy of resorption of different sizes were statistically significant (P<0.05); however, the PA radiography and CBCT, had no statistically significant differences in detection of internal resorption lesions in the cervical, middle and apical regions. Conclusion: Though, CBCT has a higher sensitivity, specificity, positive predictive value and negative predictive value in comparison with conventional radiography, this difference was not significant.Keywords: Cone-Beam Computed Tomography; Periapical Radiography; Root Resorptio

Root and Canal Morphology of Mandibular Molars in a Selected Iranian Population Using Cone-Beam Computed Tomography

Introduction: The aim of this study was to evaluate the root canal morphology of mandibular first and second molars using cone-beam computed tomography (CBCT) in northern Iranian population and also to indicate the thinnest area around root canals. Methods and Materials: We evaluated CBCT images of 154 first molars and 147 second molars. By evaluating three axial, sagittal and coronal planes of each tooth we determined the number of root canals, prevalence of C-shaped Melton types, and prevalence of Vertucci configuration and inter orifice distance. Also the minimum wall thickness of root canals was determined by measuring buccal, lingual, distal and mesial wall thicknesses of each canal in levels with 2 mm intervals from apex to orifice. Results: Amongst 154 first mandibular molars, 149 (96.7%) had two roots, 3 (1.9%) had three roots and 2 (1.2%) had C-shaped root configuration. Of 147 second mandibular molars, 120 (81.6%) had two roots, 1 (0.6%) had three roots and 26 (17.6%) had C-shaped roots. There was no significant difference in the prevalence of Vertucci’s type between two genders. The most common configuration in mesial roots of first and second molars were type IV (57%-42.9%) and type II (31.5%-28%). Mesial and distal walls had the most frequency as the thinnest wall in all levels of root canals with mostly less than 1 mm thickness. In second molars the DB-DL inter orifice distance and in first molars the MB-ML distance were the minimum. MB-D in first molars had the maximum distance while ML-DL, MB-DB and ML-D had the same and maximum distance in second molars. Conclusion: Vertucci’s type IV and type I were the most prevalent configurations in mesial and distal roots of first and second mandibular molars and the thickness of thinnest area around the canals should be considered during endodontic treatments.Keywords: Cone-Beam Computed Tomography; C-Shaped Root Canals; Mandibular First Molar; Mandibular Second Molar; Root Canal Anatomy; Root Canal Morpholog

Cone-beam computed tomography performance and endodontic filling material influence in the diagnosis of horizontal root fracture

Introduction: The aim of this study was to investigate the accuracy of Cone-beam computed tomography(CBCT) in detecting the horizontal root fractures (HRFs) in teeth with and without gutta-percha. Materials & Methods: This in vitro study was performed on 100 mandibular and maxillary single-rooted teeth. In 55 samples, the canals were prepared. Then, the horizontal fracture was induced randomly in 56 (29 with gutta-percha, 27 without gutta-percha) samples. The samples were mounted on a wax rim, and the CBCT scan was provided. The scans were examined by two endodontists twice with two-week interval. Data were analyzed using IBM SPSS 20.0 software (IBM Corp., Armonk, IL, USA). Sensitivity, specificity, accuracy, positive predictive value (PPV), negative predictive value (NPV), likelihood ratio (LR +, LR -) with 95% confidence interval were calculated. Results: The sensitivity and specificity were 72% and 100% for the group with gutta-percha as well as 89% and 100% for the group without gutta-percha, respectively. The coefficient of agreement for each observer within two observations was 0.940±0.034 and 0.960±0.028 (P<0.001). The inter observer agreement was 0.092±0.039 (P<0.001). Conclusion: The CBCT scans have high accuracy in diagnosis of horizontal root fracture and gutta-percha although they reduce the diagnostic accuracy with no significant effect

CBCT Evaluation of the Root Canal Filling Removal Using D-RaCe, ProTaper Retreatment Kit and Hand Files in curved canals

Introduction: The aim of the present in vitro study was to evaluate the efficacy of D-RaCe, ProTaper retreatment kit and hand H-files in removal of obturating materials (OM) from the curved root canals using cone-beam computed tomography (CBCT). Materials and methods: Sixty extracted molars were prepared and obturated. The samples were divided into three groups (n=20). In each group the OM was removed using hand H-files, D-RaCe and ProTaper retreatment kit. All the samples underwent CBCT imaging. The amount of OM was evaluated in CBCT sagittal cross-sections and scored. The maximum concentration of residual OM was recorded. The duration of the procedure (including the required time for reaching working length=T1 and total working time=TT) and procedural errors were also recorded. Data were analyzed using one-way ANOVA, Tukey’s post hoc test, Fisher’s exact test and Kruskal-Wallis test. The level f significance was set at 0.05. Results: No significant differences were observed in the residual OM among the three groups. T1 and TT were not significantly different in all the groups. There were no significant differences in concentration of OM between the groups (P&lt;0.05). In relation to procedural errors, 4 and 5 cases of file fracture were recorded in the ProTaper and D-RaCe groups, respectively, with no significant differences. Conclusion: Rotary and hand files had similar efficacy in removing root canal filling materials but instrument fracture occurred more frequently in rotary files

Image quality enhancement in digital panoramic radiograph

One of the most common positioning errors in panoramic radiography is palatoglossal air space above the apices of the root of maxillary teeth. It causes a radiolucency obscuring the apices of maxillary teeth. In the case of this positioning error, the imaging should be repeated. This causes the patient be exposed to radiation again. To avoid the repetition of exposing harmful X-rays to the patient, it is necessary to improve the panoramic images. This paper presents a new automatic panoramic image enhancement method to reduce the effect of this positioning error. Experimental results indicate that the enhanced panoramic images provide with adequate diagnostic information specially in maxilla sinusoid region. Hence, this technique dispenses the need for repetition of X-ray imaging

Evaluation of the Prevalence of Complete Isthmii in Permanent Teeth Using Cone-Beam Computed Tomography

Introduction: The current study aimed at determining the prevalence of complete isthmii in permanent teeth, using cone-beam computed tomography (CBCT) in a selected Iranian community. Methods and Materials: In this cross sectional study, 100 CBCT images (from 58 female and 42 male patients) including 1654 teeth (809 maxillary and 845 mandibular teeth) were evaluated. Each tooth root was evaluated in axial plane (interval, 0.1 mm; thickness, 0.1 mm) from the orifice to the apex and from the apex to the orifice to detect the presence of complete isthmus. Scans of teeth with complete isthmii were reevaluated in axial, sagittal, and coronal planes with the thickness, 0.1 mm. Presence and absence of complete isthmii in each tooth was reported. The root canal was divided into 3 equal parts (cervical, middle and apical thirds), and isthmii were classified with respect to the start and end points. Findings were classified into 6 categories with respect to the start and end points of the isthmii: 1) the beginning and end in the cervical third; 2) the beginning in the cervical third and end in the middle third ; 3) the beginning in the cervical third and end in the apical third ; 4) the beginning and end in the middle third ; 5) the beginning in the middle third and end in the apical third and 5) the beginning and end in the apical third. Results: The prevalence of complete isthmus in permanent teeth was 8.6%, and the highest prevalence was reported in mesial roots of the mandibular first molars. In maxilla, the highest prevalence of complete isthmus was found in mesiobuccal roots of the maxillary first molars, whereas in canines and central incisors, no isthmii were detected. In the mandible, the lowest prevalence of isthmus was found in second premolars. In maxillary molars, isthmii starting and ending in the middle third of the root had the highest prevalence. On the other hand, isthmii in mandibular molars, from apical or middle third of the root beginning to the end of the apical third, had the highest prevalence. Conclusion: As the prevalence of complete isthmii was the highest in molars, endodontists should pay particular attention to accomplish a successful surgical or nonsurgical root canal therapy.Keywords: Cone-Beam Computed Tomography; Root Canal Anatomy; Root Canal Isthmu

CBCT Assessment of Root Dentine Removal by Gates-Glidden Drills and Two Engine-Driven Root Preparation Systems

Introduction: The aim of this study was to compare the dentine removing efficacy of Gates-Glidden drills with hand files, ProTaper and OneShape single-instrument system using cone-beam computed tomography (CBCT). Methods and Materials: A total of 39 extracted bifurcated maxillary first premolars were divided into 3 groups (n=13) and were prepared using either Gates-Glidden drills and hand instruments, ProTaper and OneShape systems. Pre- and post-instrumentation CBCT images were obtained. The dentin thickness of canals was measured at furcation, and 1 and 2 mm from the furcation area in buccal, palatal, mesial and distal walls. Data were analyzed using one-way ANOVA test. Tukey’s post hoc tests were used for two-by-two comparisons. Results: Gates-Glidden drills with hand files removed significantly more (P&lt;0.001) dentine than the engine-driven systems in all canal walls (buccal, palatal, mesial and distal). There were no significant differences between OneShape and ProTaper rotary systems (P&gt;0.05). Conclusion: The total cervical dentine removal during canal instrumentation was significantly less with engine-driven file systems compared to Gates-Glidden drills. There were no significant differences between residual dentine thicknesses left between the various canal walls.Keywords: Cone-Beam Computed Tomography; Maxillary First Premolar; Root Canal Preparation; Root Thicknes

Prevalence and anatomical variations of maxillary sinus septa : a cone-beam computed tomography analysis

Detailed understanding the anatomy and variations of maxillary sinus septa is necessary. We aimed to investigate prevalence and various anatomical variations of maxillary sinus septa using cone-beam computed tomography (CBCT) images. In this retrospecti