Dry Human Mandibles Research Articles

Morphometric Study on the Mandibular Foramen.

Aims and objectives This study aimed to analyze the mandibular foramen (MF) by identifying its average vertical and horizontal diameters, determining its localization, and assessing the prevalence of accessory mandibular foramina. Methodology The study was conducted at the Institute of Anatomy, Madras Medical College, Chennai, India over one month in August 2024. A total of 77 human dry mandibles were examined, excluding those that were damaged to the extent that measurements could not be taken. The dimensions of the MF were measured in two directions: superoinferior and anteroposterior. Localization measurements were taken from the MF to key anatomical landmarks, including the coronoid notch, the inferior border of the ramus, the pterygomandibular raphe (third molar tooth), and the posterior border of the ramus. Measurements were recorded using digital vernier calipers and documented in Google Sheets (Google Inc., Mountain View, CA). The study also recorded the presence or absence of accessory MF. Results The superoinferior diameter of the MF was found to be 4.20 ± 0.94 mm (right (R)) and 4.28 ± 1.21 mm (left (L)). The anteroposterior diameter was found to be 3.55 ± 0.90 mm (R) and 3.60 ± 0.80 mm (L). The distance between the MF and the coronoid notch was found to be 17.60 ± 2.95 mm (R) and 17.93 ± 3.16 mm (L). The distance between the MF and the inferior border was found to be 24.61 ± 4.32 mm (R) and 24.20 ± 4.28 mm (L). The distance between the MF and the pterygomandibular raphe was found to be 20.93 ± 1.98 mm (R) and 20.63 ± 2.00 mm (L). The distance between the MF and the posterior border was found to be 11.31 ± 1.67 mm (R) and 11.70 ± 2.28 mm (L). This present study identified 20 instances of an accessory MF, with 10 occurring on each side. Additionally, 10 mandibles displayed accessory mandibular foramina on both sides. Conclusions The comprehensive analysis of the MF and its anatomical landmarks in this study offers valuable insights that enhance our understanding of mandibular anatomy, with direct implications for clinical practice. The identification of the pterygomandibular raphe as a measurable landmark from within the buccal cavity introduces a practical guide for dental practitioners and maxillofacial surgeons, potentially improving the accuracy of surgical and anesthetic procedures. Furthermore, the detailed measurements of MF width provide a foundation for refining anesthetic techniques, thereby enhancing patient outcomes. The observed prevalence of accessory MF underscores the importance of considering anatomical variability in clinical practice, highlighting the need for continuous anatomical research to advance clinical methodologies and ultimately improve patient care and surgical success.

Assessment of Diagnosis of Apical Root Fractures During Tooth Extraction Using Different Radiographic Techniques: An Ex-vivo Study

Objective: This study aimed to examine the diagnostic ability of different imaging techniques for apical root fractures that occur during tooth extraction by specialist dentists in different branches. Methods: Dry human mandibles used for education at Faculty of Dentistry and teeth extracted for routine treatment were used. After the root lengths were measured using a periodontal probe, the samples were adjusted to different lengths. These specimens were placed on a dry human mandible, and images were obtained and recorded using a periapical device, panoramic device, and computed tomography. Radiographs and recordings were performed by an oral and maxillofacial radiologist. The evaluation process was performed by an oral and maxillofacial radiologist, periodontologist, and oral and maxillofacial surgeon. Results: The diagnosis of 1 mm root presence and absence on periapical radiographs showed significant agreement among all observers. In the presence of 2 mm and 3 mm roots, all observers stated that the roots were present. On the panoramic radiographs, moderate agreement was observed in teeth with a 1 mm root. However, poor agreement between observers was observed for teeth with 2 mm and 3 mm roots. Cone-beam computed tomography (CBCT) was effective for the diagnosis of all observers. Conclusion: Consistent with the literature, the present study showed a higher interobserver agreement in CBCT. However, considering the patient's anxiety during the procedure, the duration of local anesthesia, and the surgeon's fatigue, two-dimensional radiographs are generally preferred over CBCT, which has a longer image processing time. Diagnosis using periapical radiographs was more effective than that using panoramic radiographs.

Analysis of Shape of Lingula in Dry Adult Human Mandible in a Bangladeshi Population

The lingula is an important anatomical landmark used in oral and dental surgeries and to block the inferior alveolar nerve. Our study aims to analyze different types of lingula found in mandibles of Bangladeshi individuals. This cross-sectional, descriptive study was done on 150 fully ossified dry human mandibles in the Department of Anatomy, Mymensingh Medical College, Mymensingh, Bangladesh between July 2019 and June 2020. A non-random purposive sampling technique was adopted. The lingula was classified into four types: triangular, truncated, nodular and assimilated. The triangular shape was most commonly found (67%), followed by truncated (19.33%), nodular (9.66%) and assimilated (4%). On right side of the mandible, the triangular shape was present in 61.33% samples and on left side, in 59.33% samples. Truncated shape was found 25.33% on right side and 26.66% on left. Nodular shape was present in 10% on right side and 9.33% on left. Assimilated shape was observed in 3.33% on right side and 4.66% on left. Knowledge of various morphological shapes helps dental and maxillofacial surgeons to preserve important structures like inferior alveolar nerve and vessels during surgical interventions of mandible. Our data is expected to increase the information pool, which will be useful for further anthropological studies. CBMJ 2024 July: vol. 13 no. 02 P: 223-226

A Morphometric Study of the Retromolar Fossa and the Incidence of the Retromolar Foramen in Dry Human Mandibles.

The mandible is the largest and strongest facial bone which plays a crucial role for various surgeries and diagnostic imaging. The retromolar fossa, located behind the third molar socket on each side, was observed for morphometry of anterior, medial, and posterior borders. The present study aimed to assess the retromolar fossa and the presence of retromolar foramen. This cross-sectional study was conducted on 30 dry mandibles of adult humans of unknown sex; morphometry of retromolar foramen was done using three parameters: anteriorly, laterally, and posteroinferiorly. Dimensions of the retromolar trigone were seen with notable differences between the right and left sides. Dimensions of the anterior border had a mean of 12.34±1.175 mm on the right side and 12.56±1.46 mm on the left side. The mean of the medial border of the trigone on the right side was 20.23±2.84 mm and on the left side was 21.48±2.57 mm. The lateral border had the mean value of 18.33±3.56 mm and 19.21±3.93 mm on the right and left sides respectively. The P-value of the medial border was found to be statistically significant (P=0.02). Retromolar foramen was observed in 60% of mandibles; six were unilateral and 12 were bilateral. These foramina were closer to the anterior border of the retromolar trigone as compared to the anterior border of the ramus and lingula of the mandibles. The awareness of these findings is crucial for the prevention of complications, such as neurovascular damage, during surgeries in this region. This knowledge is particularly relevant in addressing oral pathologies and extracting third molars, contributing to improved surgical outcomes and patient safety.

Unilateral Large Mylohyoid Bridging the Dry Human Mandible

Unilateral Large Mylohyoid Bridging the Dry Human Mandible

Do the number of zirconia implants and the thickness of CBCT image reconstruction affect the detection of peri-implant bone defect? A diagnostic accuracy exvivo study.

To evaluate the influence of multiplanar reconstruction thickness on the detection of peri-implant bone defects with a standalone zirconia implant and compare it to when another implant is in the vicinity using cone-beam computed tomography (CBCT). Five dry human mandibles were used to create twenty implant sites in the second premolar and first molar regions. The OP300 Maxio was used to acquire CBCT images (90 kVp, 6.3 mA, 5 × 5 cm FOV, and 0.125 mm3 voxel size) before and after creating 3 mm peri-implant bone defects in the buccal aspect of the premolar region. Half of the scans featured a single zirconia implant in the premolar region, while the others had two implants in the premolar and molar regions. Three reconstruction thicknesses (0.125 mm, 1 mm, and 2 mm) were considered for the multiplanar reconstruction analyses. Five oral and maxillofacial radiologists assessed the detection of peri-implant bone defects using a 5-point scale. Diagnostic parameters were calculated and compared using Two-way ANOVA (α = .05). The studied factors showed no significant influence on the diagnosis of peri-implant bone defects (p > .05). Diagnostic performance was notably higher with a single implant, especially with a 2-mm reconstruction thickness (AUC = 0.88, sensitivity = 0.68, specificity = 0.94). Although the differences were not statistically significant, the results were more modest when two implants were present (AUC = 0.80, sensitivity = 0.58, specificity = 0.82). The presence of an adjacent zirconia implant and variations in reconstruction thickness did not influence the detection of 3 mm buccal peri-implant bone defects on CBCT images.

Influence of tube current and metal artifact reduction on the diagnosis of external cervical resorption in teeth adjacent to a dental implant in CBCT: an ex-vivo study.

This ex-vivo study aimed to assess the influence of tube current (mA) and metal artifact reduction (MAR) on the diagnosis of early external cervical resorption (EECR) in cone-beam computed tomography (CBCT) in the presence of an adjacent dental implant. Twenty-three single-rooted teeth were sectioned longitudinally and EECR was induced using a spherical drill and 5% nitric acid in 10 teeth. Each tooth was positioned in the socket of the lower right canine of a dry human mandible and CBCT scans were acquired using 90 kVp, voxel of 0.085 mm, field of view of 5 x 5 cm, and varying tube current (4, 8 or 12 mA), MAR (enabled or disabled) and implant conditions (with a zirconia implant in the socket of the lower right first premolar or without). Five oral radiologists evaluated the presence of EECR in a 5-point scale and the diagnostic values (area under the receiver operating characteristic curve - AUC, sensitivity, and specificity) were compared using multi-way Analysis of Variance (α = 0.05). Kappa test assessed intra-/inter-evaluator agreement. The tube current only influenced the AUC values in the presence of the implant and when MAR disabled; in this case, 8 mA showed lower values (p<0.007). MAR did not influence the diagnostic values (p>0.05). In general, the presence of an implant reduced the AUC values (p<0.0001); sensitivity values with 8 mA and MAR disabled, and specificity values with 4 mA and MAR enabled and 8 mA regardless MAR were also decreased (p<0.0001). Variations in tube current and MAR were unable to improve EECR detection, which was impaired by the presence of an adjacent implant. Increasing tube current or activating MAR tool does not improve EECR diagnosis, which is hampered by the artifacts generated by dental implants.

Effect of different cone beam computed tomography settings on artifact production in titanium and zirconia dental implants: An in vitro study.

The use of dental implants in the treatment of edentulous patients is increasing. Zirconia implants are an alternative to titanium implants, offering advantages in terms of aesthetics and biological compatibility. However, the number of artifacts observed on radiographic images with zirconia implants compared to titanium implants is yet to be determined. The purpose of this study was to evaluate the impact of different cone-beam computed tomography (CBCT) parameters on the production of artifacts in zirconia and titanium implants. A dry human mandible was coated with wax to simulate human soft tissues and examined. Subsequently, titanium and zirconia implants were placed at the same points in the posterior region of the mandible. The production of artifacts on CBCT scans was evaluated using 2 parameters. The first parameter, the standard deviation within the region of interest (SDROI), is based on a comparison of the gray levels at implant and control areas. The second parameter was the contrast-to-noise ratio (CNR), which was evaluated for different protocols created by various combinations of the field of view (FOV) area, milliampere [mA] intensity and metal artifact reduction (MAR) programs. The study found that zirconia implants produced more artifacts than titanium implants. However, the production of artifacts in zirconia implants could be significantly reduced by increasing the mA values, performing CBCT scans with smaller FOV areas, and enabling MAR programs. The production of artifacts is a disadvantage of zirconia implants, but this drawback can be mitigated by selecting appropriate protocols for the CBCT device.

Exploring the morphological and morphometric characteristics of the mandibular lingula in dry mandibles of South African population

BackgroundThe lingula of the mandible is a small tongue-shaped bony prominence that partially overlaps the mandibular foramen. It has variable shapes among different populations which impacts its significance as a bony landmark in maxillofacial and oral surgeries. This study aimed to explore the morphological and morphometric characteristics of the mandibular lingula in dry mandibles of a South African population, to provide more knowledge on its structural variations, and location for surgeons involved with maxillofacial and oral surgeries. MethodologyThe study utilized 45 (n = 90 sides) dry human mandibles. The shapes were classified into five types, as per the classification scheme proposed by Tuli et al. (2000) and Varma and Sameer (2013). Three morphometric parameters were utilized to determine the location of the lingula. A p-value of <0.05 was considered statistically significant. ResultsThe most common type of the lingula was the truncated type 36/90 (40%), followed by the triangular type 23/90 (25.56%) and, nodular type 22/90 (24.44%). The mean height (mean ± SD) of the lingula was 7.57 ± 1.56 mm. The mean distance from the lingula to the anterior border of the mandibular ramus was 20.05 ± 3.25 mm while the mean distance from the lingula tip to the posterior border of the ramus of the mandible was 16.58 ± 2.26 mm. The mean distance was 15.81 ± 2.15 mm from the lingula to the mandibular notch. ConclusionThe present study contributes to the existing body of knowledge on the structural variation of the lingula which is important for precise location of the mandibular foramen and related structures, especially when performing any maxillofacial surgical procedures within a South African population group.

The added effect of artifact reduction algorithm and ultra-low dose protocols on the accuracy of measurements obtained using Planmeca Viso G7 cone beam computed tomography

Objective The aim of this study is to evaluate the accuracy of linear and volumetric measurements using Planmeca Viso G7 cone beam computed tomography (CBCT) examinations acquired with ultra-low dose (ULD) and metal artifact reduction algorithm (ARA) protocols. Materials and methods Eight metallic spherical objects different in size with pre scanning diameter measurements using a calibrated digital caliper were fixed on a five dry human mandible. The real physical diameters and linear measurements between the metallic objects were measured. A CBCT acquisition was obtained four times with the same proper field of view, 150 μm and 100 Kv, in four scans using the Planmeca Viso G7 CBCT, machine acquisition was done with and without ARA, ULD, which is ARA, and ULD. Both acquisition protocols are inherited options in the Planmeca Viso G7 CBCT machine. All images were interpreted with the Planmeca Romexis software. Results Linear and volumetric measurements were found to have a nonstatistically significant difference with real measurements in the acquisition with ARA and ULD, but with a statistically significant difference with the other three acquisition sequences. Conclusions Using the ARA in combination with the ULD as an acquisition tool in the CBCT machine results in accurate linear and volumetric measurements, enhances image quality, and reduces metallic artifact with the lowest radiation dose.

Morphological Changes and Gender-Based Differences in Human Dry Mandible

Morphological Changes and Gender-Based Differences in Human Dry Mandible

Impact of enhancement filters of a CMOS system on halo artifact expression at the bone-to-implant interface.

To assess the impact of enhancement filters on the formation of halo artifacts in radiographs of dental implants obtained with a complementary metal oxide semiconductor (CMOS) system. Digital radiographs of dental implants placed in dry human mandibles were processed with the Noise Reduction smoothing filter, as well as the Sharpen 1, Sharpen 4, and Sharpen UM high-pass filters available in the CLINIVIEW™ software (Instrumentarium Dental, Tuusula, Finland). Subjective analysis involved evaluating the left, right, and apical surfaces of each implant for the presence of much, few, or no halo. The objective analysis involved measurement of the halo area using the Trainable Weka Segmentation plugin (ImageJ, National Institutes of Health, Bethesda, MD, USA). Data were analyzed using Friedman's test (subjective analysis) and ANOVA (objective analysis) (α = 5%). In the subjective evaluation, the Sharpen 4 filter produced more radiographs with much halo present, and in the objective evaluation, a bigger halo area when compared to the original images and the Noise Reduction filter for all surfaces (p < 0.05). When evaluating dental implants, priority should be given to original images and those enhanced with smoothing filters since they exhibit fewer halo artifacts. Post-processing tools, such as enhancement filters, may improve the image quality and assist some diagnostic tasks. However, little is known regarding the impact of enhancement filters in halo formation on CMOS systems, which have been increasingly used in dental offices.

Influence of exposure protocol, voxel size, and artifact removal algorithm on the trueness of segmentation utilizing an artificial-intelligence-based system.

To evaluate the effects of exposure protocol, voxel sizes, and artifact removal algorithms on the trueness of segmentation in various mandible regions using an artificial intelligence (AI)-based system. Eleven dry human mandibles were scanned using a cone beam computed tomography (CBCT) scanner under differing exposure protocols (standard and ultra-low), voxel sizes (0.15mm, 0.3mm, and 0.45mm), and with or without artifact removal algorithm. The resulting datasets were segmented using an AI-based system, exported as 3D models, and compared to reference files derived from a white-light laboratory scanner. Deviation measurement was performed using a computer-aided design (CAD) program and recorded as root mean square (RMS). The RMS values were used as a representation of the trueness of the AI-segmented 3D models. A 4-way ANOVA was used to assess the impact of voxel size, exposure protocol, artifact removal algorithm, and location on RMS values (α = 0.05). Significant effects were found with voxel size (p < 0.001) and location (p < 0.001), but not with exposure protocol (p = 0.259) or artifact removal algorithm (p = 0.752). Standard exposure groups had significantly lower RMS values than the ultra-low exposure groups in the mandible body with 0.3mm (p = 0.014) or 0.45mm (p < 0.001) voxel sizes, the symphysis with a 0.45mm voxel size (p = 0.011), and the whole mandible with a 0.45mm voxel size (p = 0.001). Exposure protocol did not affect RMS values at teeth and alveolar bone (p = 0.544), mandible angles (p = 0.380), condyles (p = 0.114), and coronoids (p = 0.806) locations. This study informs optimal exposure protocol and voxel size choices in CBCT imaging for true AI-based automatic segmentation with minimal radiation. The artifact removal algorithm did not influence the trueness of AI segmentation. When using an ultra-low exposure protocol to minimize patient radiation exposure in AI segmentations, a voxel size of 0.15mm is recommended, while a voxel size of 0.45mm should be avoided.

The Effect of Head Position on Buccal Cortical Bone Thickness Measurements in CBCT Scans: A Human Dry Mandible Study

Objective: The aim of this study was to compare buccal cortical bone thickness measurements on cone beam computed tomography (CBCT) scans of human dry mandibles with direct measurements and to evaluate the effect of different head positioning on measurements. Methods: In total, direct linear measurements were made at reference points on the buccal bone surfaces in toothless sockets in 26 human dry mandibles. CBCT scans were performed in the central position and with four different types of head position (to the right-left, to the anterior-posterior). Thickness measurements were performed on cross-sectional sections from relevant areas where heated gutta-percha was placed. Measurements were summarized as mean±standard deviation. Differences between measurements were analyzed by ANOVA and Friedmann test. Results: Compared to direct measurements, buccal cortical bone thickness in CBCT scans was higher in the incisor and premolar regions, while lower values were obtained in the molar region. These differences were statistically significant but less than 0.2 mm (p&lt;0.005). Different head positions had no effect on measurements on CBCT images (p&gt;0.005). Intraobserver agreement for buccal bone thickness was found to be high (ICC=0.902-0.976). Conclusion: It demonstrated a clinically acceptable difference between direct measurements and CBCT measurements of mandibular buccal cortical bone thickness. Additionally, no differences in measurements were observed between different types of head positions.

A morphometric study of Bonwill’s triangle for gender differences in dry mandibles of the Indian population

Bonwill's triangle, an imaginary equilateral triangle of the mandible, can cause mandibular alignment issues in post-dental occlusion, complete dentures, and mandibular fractures due to incorrect measurements across genders. This study aimed to analyze Bonwill's triangle size in dry mandible bones of the Indian population, focusing on gender differences to create error awareness in dental treatments and mandibular fractures. The study involved fifty-three dry human mandibles, segregated into male and female based on metric and non-metric parameters. The study measured the distances between the center of the right condyle to the midpoint of medial mandibular incisors (X-Y), the center point of the left condyle to the midpoint of medial mandibular incisors (Y-Z), and the center point of both condyles (Z-X). The mean lengths of Bonwill's triangular measurements in males were X-Y (101.08 mm), Y-Z (100.39 mm), and Z-X (97.06 mm), while females had 100.3 mm, 99.45mm, and 93.41mm respectively. Only two sides of the triangle were in accordance with Bonwill's theory. In the Indian population, Bonwill's triangle was significantly larger in male mandibles, and the intercondylar distance (Z-X) was less than 100mm in both genders, resulting in an isosceles triangle. Bonwill's triangle serves as a basis for modern technology to find geometric parameters for fractured mandibles and dental procedures, sex identification in forensic dentistry, anthropological studies, and bone grafts.

Use of Adult Dry Human Mandibles to Study of Mandibular Foramen from Various Bony Landmarks.

Precise knowledge of the mandibular foramen's location is essential for clinical and surgical procedures, especially the inferior alveolar nerve block. Variability in its position concerning different bony landmarks can significantly impact clinical outcomes. This study examined 30 Adult dry human mandibles to determine the mandibular foramen's positions in relation to specific bony landmarks: the occlusal plane, posterior border of the ramus, and lingula. Measurements were obtained using a calibrated digital caliper, and statistical analysis was performed. The study revealed significant variations in the position of the mandibular foramen. In relation to the occlusal plane, the mandibular foramen was found at an average height of approximately 15.2 mm (±2.1 mm). Regarding the posterior border of the ramus, it was situated at an average distance of about 18.5 mm (±3.4 mm). In relation to the lingula, the average distance was approximately 21.8 mm (±4.0 mm). These results underscore the considerable individual differences and anatomical variations in the mandibular foramen's location among the studied specimens. The observed variations in the position of the mandibular foramen emphasize the need for clinicians and surgeons to be cognizant of these differences when performing procedures involving the inferior alveolar nerve block. Understanding these anatomical variations is crucial for enhancing clinical precision, reducing complications, and ensuring optimal outcomes.

Accuracy of formula-based volume and image segmentation-based volume in calculation of preoperative cystic jaw lesions’ volume

ObjectiveThe aim of this study was to assess the accuracy of formula-based volume measurements and the 3D volume analysis with different software packages in the calculation of preoperative cystic jaw lesions’ volume. The secondary aim was to assess the reliability and the accuracy of 3 imaging software programs for measuring the cystic jaw lesions' volume in CBCT images.Materials and methodsThis study consisted of two parts: an in vitro part using 2 dry human mandibles that were used to create simulated osteolytic lesions to assess the accuracy of the volumetric analysis and formula-based volume. As a gold standard, the volume of each bone defect was determined by taking an impression using rapid soft silicone (Vinylight) and then quantifying the volume of the replica. Afterward, each tooth socket was scanned using a high-resolution CBCT. A retrospective part using archived CBCT radiographs that were taken from the database of the outpatient clinic of the oral and maxillofacial radiology department, Faculty of Dentistry, Minia University to assess the reliability of the 3 software packages. The volumetric data set was exported for volume quantification using the 3 software packages (MIMICS-OnDemand and InVesalius software). Also, the three greatest orthogonal diameters of the lesions were calculated, and the volume was assessed using the ellipsoid formula. Dunn’s test was used for pair-wise comparisons when Friedman’s test was significant. The inter-examiner agreement was assessed using Cronbach’s alpha reliability coefficient and intra-class correlation coefficient.ResultsRegarding the results of the retrospective part, there was a statistically significant difference between volumetric measurements by equation and different software (P value < 0.001, Effect size = 0.513). The inter-observer reliability of the measurements of the cystic lesions using the different software packages was very good. The highest inter-examiner agreement for volume measurement was found with InVesalius (Cronbach’s alpha = 0.992). On the other hand, there was a statistically significant difference between dry mandible volumetric measurements and Gold Standard. All software showed statistically significantly lower dry mandible volumetric measurements than the gold standard.ConclusionComputer-aided assessment of cystic lesion volume using InVesalius, OnDemand, and MIMICS is a readily available, easy to use, non-invasive option. It confers an advantage over formula-based volume as it gives the exact morphology of the lesion so that potential problems can be detected before surgery. Volume analysis with InVesalius software was accurate in determining the volume of simulated periapical defects in a human cadaver mandible as compared to true volume. InVesalius software proved that open-source software can be robust yet user-friendly with the advantage of minimal cost to use.

Radiographic evaluation of mandibular third molars: an ex vivo comparative study between multilayer and conventional panoramic radiography.

To compare the multilayer panoramic radiography (MPAN) and conventional panoramic radiography (CPAN) in the evaluation of mandibular third molars using cone-beam computed tomography (CBCT) as a reference. CPAN, MPAN, and CBCT scans from 33 dry human mandibles were acquired using the OP300 Maxio unit, totalizing 56 mandibular third molars to be evaluated. Three examiners evaluated each third molar according to their position, depth of impaction in the mandibular ramus, proximity between the dental root apexes and the mandibular canal, and the presence of radiographic signs of proximity to the mandibular canal. In addition, when there was a distance between the root apexes and the mandibular canal, it was measured. As a reference, these same parameters were assessed in the CBCT scans by a fourth examiner. For the statistical analysis, the weighted Kappa, Bland Altman, and Wilcoxon tests were performed (α = 0.05). The agreement between the assessments performed in the panoramic modalities with the CBCT ranged from 66.1% to 100.0% for the categorical variables. Overall, the agreement values of CPAN and MPAN with CBCT were similar. The distances between the dental root apex and the mandibular canal for both CPAN and MPAN were significantly underestimated compared to CBCT (p < 0.05). The intra- and interexaminer agreements of the examiners ranged from poor to almost perfect; in general, the agreements were higher in the evaluation performed in the MPAN than in the CPAN. The MPAN performs similarly to CPAN for evaluating mandibular third molars and their proximity relationship to the mandibular canal. Preoperative evaluation of lower mandibular third molars is usually performed using CPAN. Recently, a new tool, MPAN, was developed, which has not yet been tested for the evaluation of mandibular third molars and showed similar performance to CPAN in the present study. Future studies using MPAN are encouraged to evaluate other diagnostic tasks.

Ex vivo detection of mandibular incisors’ root canal morphology using cone-beam computed tomography with 4 different voxel sizes and micro-computed tomography

BackgroundIn recent years, cone-beam computed tomography (CBCT) has been widely used to evaluate patients’ root canal anatomy due to its high resolution and noninvasive nature. As voxel size is one of the most important parameters affecting CBCT image quality, the current study evaluated the diagnostic potential of CBCT with 4 different voxel sizes in the detection of double root canal systems and accessory canals (ACs) in permanent mandibular incisors.MethodsA total of 106 extracted mandibular permanent incisors were collected from the dental clinics, and then were scanned by using micro-CT with a voxel size of 9 μm. The teeth were then fixed in the tooth sockets of human dry mandibles and scanned by using a CBCT device with 4 different voxel sizes (300, 200, 250, and 125 μm). Four observers detected in blind the root canal morphology of the teeth according to the CBCT images, and the presence or absence of a double root canal system, and the presence or absence of ACs, were scored according to a 5-point scale, respectively. Receiver operating characteristic (ROC) analysis was performed, and DeLong test was used to compare the area under the curve (AUC) values and the micro-CT data was taken as a gold standard.ResultsAmong 106 sample teeth, 25 specimens with a double root canal system were identified by the micro-CT. ROC curve analysis of the data obtained by the four observers showed that in the detection of double root canal systems, the AUC values ranged from 0.765 to 0.889 for 300 μm voxel size, from 0.877 to 0.926 for 250 μm voxel size, from 0.893 to 0.967 for 200 μm voxel size, and from 0.914 to 0.967 for 125 μm voxel size (all p < 0.01). In general, we observed a trend that the AUC values, sensitivity, and specialty increased with the decrease in the voxel size, and significantly higher AUC values were detected in 125 μm voxel size images. In the detection of ACs, ROC curve analysis showed that among the four observers, the AUC values ranged from 0.554 to 0.639 for 300 μm voxel size, from 0.532 to 0.654 for 250 μm voxel size, from 0.567 to 0.626 for 200 μm voxel size, and from 0.638 to 0.678 for 125 μm voxel size. CBCT images at a voxel size of 125 μm had a weak diagnostic potential (AUC: 0.5–0.7, all p < 0.05) in the detection of AC, with a lower sensitivity ranging from 36.8 to 57.9% and a higher specialty ranging from 73.6 to 98.8%.ConclusionsCBCT with 300 μm voxel size could only provide moderate diagnostic accuracy in the detection of a double canal system in mandibular incisors. CBCT with a voxel size of 125 μm exhibited high diagnostic value in the detection of double canal systems, while showing low but statistically significant value in the detection of ACs.

Accuracy of linear mandibular measurements on conventional and cone beam computed tomography reconstructed panoramic radiographs

Introduction: The aim of the study was to evaluate and compare the precision of dimensional measurements in digital panoramic radiographs (PRs) and cone beam computed tomography (CBCT)-generated panoramic images. Materials and Methods: Ten dry human mandibles were subjected to direct anthropometric measurements, digital panoramic radiography, and CBCT scans. Vertical and horizontal measurements were made between predetermined points by two observers. Paired t-test was applied for the comparative analysis. p value &lt;0.05 was considered statistically significant. Analysis of variance (ANOVA) was done followed by post-hoc Bonferroni test to correlate the measurements got by the three modalities. Results: Except for two vertical measurements (V2 and V4) there was statistically significant difference in relation to all the measurements. The highest mean difference was observed in relation to H4, which was 12.60 mm lesser on digital PR in comparison to the anatomic measurements. Also, except for two vertical measurements V1 and V5, all the other measurements were underestimated by the digital PR.Conclusion: Measurement done in reconstructed PR and digital PRs in the region of posterior tooth-bearing region and condylar region are statistically similar.