Dry Human Mandibles Research Articles

A Morphometric Study of Mental Foramen of Adult Human Dry Mandibles

A Morphometric Study of Mental Foramen of Adult Human Dry Mandibles

A Morphological Study of Coronoid Process of Adult Human Dry Mandibles

A Morphological Study of Coronoid Process of Adult Human Dry Mandibles

The Performance of a Zirconium-based Root Filling Material with Artifact Reduction Properties in the Detection of Artificially Induced Root Fractures Using Cone-beam Computed Tomographic Imaging

IntroductionLimited field of view cone-beam computed tomographic (CBCT) imaging has been used to augment clinical testing of vertical root fractures (VRFs); however, the presence of gutta-percha (GP) in the canal space generates substantial imaging artifacts that make fracture detection difficult. The purpose of this study was to evaluate the influence of a zirconium (Zr)-based root filling material with radiologic properties that reduce beam hardening (BH) artifacts using CBCT imaging in the in vitro diagnosis of VRFs. MethodsOne hundred seventy-six single-rooted mandibular premolar teeth were obtained, and half of these teeth were filled with GP or Zr (CPoint; EndoTechnologies, LLC, Shrewsbury, MA). VRFs were induced in 44 decoronated teeth in each group using an Instron (Norwood, MA) Universal Testing Machine. Each root was then placed in a dry human mandible and imaged with the Carestream 9000 3D CBCT system (Carestream Dental, Atlanta, GA). The images were evaluated by 6 oral maxillofacial radiologists (OMRs) and residents. ResultsThe sensitivity was greater for detecting VRFs in the Zr group than the GP group (P = .035). However, the specificity was greater for the GP group than the Zr group (P = .028). Receiver operating characteristic area under the curve values were greater for the Zr group than the GP group, but these differences were not statistically significant. The OMRs outperformed the residents in the detection of VRFs in the Zr group with respect to specificity (P = .006) and positive predictive value (P = .012). ConclusionsThe reduced BH of the Zr group improved the sensitivity of the detection of artificially induced VRFs. The ability to detect VRFs in the Zr group was further enhanced by clinical experience.

Accuracy and reliability of tooth length measurements on conventional and CBCT images: An in vitro comparative study.

CONTEXT:The purpose of this study was to evaluate the accuracy and reliability of tooth length measurements using conventional and cone-beam computed tomography (CBCT) imaging techniques.AIM:The aim of this study was to assess the accuracy and reliability of various tooth length measurements made on CBCT scans and conventional imaging techniques [intraoral periapical radiograph (IOPA) and orthopantomogram (OPG)].SETTINGS AND DESIGN:This is an in-vitro comparative study.SUBJECTS AND METHODS:In total, 50 extracted single-rooted premolar teeth were mounted on the dry human mandible. For each extracted tooth, measurements for tooth length, crown length, and root lengths were taken with a Vernier caliper and using three imaging modalities: CBCT, OPG, and IOPA radiographs. The measurements were compared with the gold standard (Vernier caliper).STATISTICAL ANALYSIS USED:One-way analysis of variance was used to compare mean values between the groups that are Vernier caliper, CBCT, IOPA, and OPG. The multiple comparisons of means of tooth length, root length, and crown length were done by Bonferroni test.RESULTS:A significant difference in the tooth length measurements was seen between the measurements taken by CBCT and IOPA and between IOPA and OPG. But, no significant difference was seen between any other groups. The highly significant difference was seen between the root length measurements taken by IOPA and OPG and by CBCT and OPG. However, no significant difference was seen between any other groups. No significant difference was seen in between the crown length measurements taken by Vernier caliper and CBCT and between IOPA and OPG. However, a significant difference was seen between all the groups.CONCLUSIONS:Among the radiographic techniques, CBCT was found to be the most accurate in measuring the tooth, root, and crown lengths.

Morphological and morphometric analysis of accessory mental foramen in dry human mandibles of south indian population

Mental foramen (MF) is an important landmark for administration of local anesthesia in surgical procedures involving the mandible. Additional mental foramina, called accessory mental foramina (AMF) transmitting branches of mental nerve, have been reported. Detection of AMFs in presurgical imaging may reduce postoperative pain in dental surgical procedures. Aim: The aim of the study was to study the incidence and morphometric analysis of accessory MF in the dry human mandibles of South Indian population. Two hundred and sixty dry human mandibles were studied for the presence, location, shape of AMF, and its relation to MF. The horizontal diameter of AMF, and its distance from symphysis menti, the posterior border of mandible and from the base of mandible were measured and statistically analyzed. In our study, AMF were present in 8.85% mandibles (unilateral - 7.6% [4.6% - left, 2.69% - right] and bilateral 1.6%). The most common position was below the second premolar (48.1%). AMF were round in shape (74%) and was often located either superomedial or inferolateral to MF. Their transverse diameter ranged from 0.5 to 1 mm. The AMF were situated at a mean distance of 2.96 mm from MF, 23.47 mm from symphysis menti, 11.24 mm from the lower border of the body of the mandible, and 57.35 mm from the posterior border of ramus of mandible. The knowledge of the presence of AMF and its dimensions would enable the clinicians to do mandibular procedures carefully and avoid injury to the branches of mental nerve that may be passing through it.

Dimensional Error in Rapid Prototyping with Open Source Software and Low-cost 3D-printer.

Summary:Rapid prototyping models (RPMs) had been extensively used in craniofacial and maxillofacial surgery, especially in areas such as orthognathic surgery, posttraumatic or oncological reconstructions, and implantology. Economic limitations are higher in developing countries such as Mexico, where resources dedicated to health care are limited, therefore limiting the use of RPM to few selected centers. This article aims to determine the dimensional error of a low-cost fused deposition modeling 3D printer (Tronxy P802MA, Shenzhen, Tronxy Technology Co), with Open source software. An ordinary dry human mandible was scanned with a computed tomography device. The data were processed with open software to build a rapid prototype with a fused deposition machine. Linear measurements were performed to find the mean absolute and relative difference. The mean absolute and relative difference was 0.65 mm and 1.96%, respectively (P = 0.96). Low-cost FDM machines and Open Source Software are excellent options to manufacture RPM, with the benefit of low cost and a similar relative error than other more expensive technologies.

A morphometric study of the mandibular foramen in dry adult human mandibles – A study in RIMS, Imphal

A morphometric study of the mandibular foramen in dry adult human mandibles – A study in RIMS, Imphal

An anatomical study and clinical co-relations of mandibular foramen in dry adult human mandibles of north Indian origin

Background: The mandibular foramen is located on the medial surface of ramus of mandible. It transmits inferior alveolar nerve. Inferior alveolar nerve block is a common procedure done by dental practitioners while doing various surgeries on mandible. The aim of this study is to determine the position of mandibular foramen in respect to various landmarks present on mandible. Methods: 30 adult human dry mandibles of north Indian origin were studied. The position of mandibular foramen from various landmarks was measured on both sides of mandibular ramus. Results: In our study we found the mean distance from the mandibular foramen to the anterior border of the ramus was 16.06±1.99 mm and 16.13±2.10 mm on the right and left sides respectively and from the mandibular foramen to the posterior border of the ramus was 12.02±1.99 mm and 11.10±1.95 mm on the right and left sides respectively. The mandibular foramen was situated at a mean distance of 1.36±0.77 mm on the right side and 1.47±0.72 mm on the left side, posterior to the midpoint of width of the ramus and at a mean distance of 3.37±1.37 mm on the right side and 3.10±1.41 mm on the left side, superior to the midpoint of vertical height of the ramus. Conclusion: In present study localization of mandibular foramen presented great variation. However if we keep these anatomical landmarks in our mind we can accurately locate the position of mandibular foramen and this will help us to create successful anesthesia and to perform good surgeries on mandible.

An in vitro comparison of linear measurements of panoramic views acquired via 2D or 3D imaging

Introduction: Panoramic radiography and CBCT are common imaging techniques in general dental practice. Some clinicians still refer patients for additional conventional digital panoramic radiographs despite the fact that CBCT data has already been acquired. The purpose of this study was to evaluate the efficacy of Digital panoramic radiographic images derived from conventional and CBCT generated methods, regarding their linear measurements’ accuracy in different anatomical sites in dry human mandibles compared to real measurements obtained by a digital vernier caliper. Materials and Methods: Measurements from five adult human dry mandibles were made separately on the right and left sides ending up with ten evaluated samples. Several linear measurements related to mental and mandibular foramina were obtained. All were compared to real measurements.Results: Cronbach’s alpha inter- and intra- observer agreement in all modalities used ranged from “very good to perfect”. No statistically significant difference between linear measurements’ means in all modalities used when compared to real ones. Only two measurements; one was significantly underestimated in all modalities, the other was significantly overestimated in manual reformatted panoramic.Conclusion: Comparable results were shown when linear measurements’ means from Digital panoramic, CBCT derived Auto and Manual reformatted panoramic were compared to real ones. Radiation dose to patients must be concerned.

Influence of acquisition parameters on the evaluation of mandibular third molars through cone beam computed tomography

The aim of the study was to assess the influence of cone beam computed tomography (CBCT) acquisition parameters on the evaluation of mandibular third molars and their relationship to the mandibular canal. Eight dry human mandibles with 13 mandibular third molars were scanned with one CBCT unit. Voxel size (0.2and 0.3mm), field of view (FOV) size (12×8.5cm and 5×5cm), and number of basis images (450 and 720) were the variables studied. Two examiners evaluated the images, and the resulting data were compared through McNemar, McNemar-Bowker, and Student t tests. Additionally, dosimetry was determined for all protocols tested, and radiation doses were compared through analysis of variance. The variables did not influence evaluation of mandibular third molars, except for voxel size, when assessing contact between the tooth and the mandibular canal (P=.021). Although FOV and number of basis images affected radiation dose, voxel size did not. FOV size and number of basis images did not influence the evaluation of mandibular third molars and their relationship to the mandibular canal in the CBCT unit used. Conversely, smaller voxel size affected the assessment of contact between the tooth and the mandibular canal. In units in which voxel size does not influence radiation dose, the mostappropriate CBCT protocol is the one using a smaller voxel size and delivering the lowest radiation dose to the patient.

A new method to evaluate image quality of CBCT images quantitatively without observers

To develop an observer-free method for quantitatively evaluating the image quality of CBCT images by applying just-noticeable difference (JND). We used two test objects: (1) a Teflon (polytetrafluoroethylene) plate phantom attached to a dry human mandible; and (2) a block phantom consisting of a Teflon step phantom and an aluminium step phantom. These phantoms had holes with different depths. They were immersed in water and scanned with a CB MercuRay (Hitachi Medical Corporation, Tokyo, Japan) at tube voltages of 120 kV, 100 kV, 80 kV and 60 kV. Superimposed images of the phantoms with holes were used for evaluation. The number of detectable holes was used as an index of image quality. In detecting holes quantitatively, the threshold grey value (ΔG), which differentiated holes from the background, was calculated using a specific threshold (the JND), and we extracted the holes with grey values above ΔG. The indices obtained by this quantitative method (the extracted hole values) were compared with the observer evaluations (the observed hole values). In addition, the contrast-to-noise ratio (CNR) of the shallowest detectable holes and the deepest undetectable holes were measured to evaluate the contribution of CNR to detectability. The results of this evaluation method corresponded almost exactly with the evaluations made by observers. The extracted hole values reflected the influence of different tube voltages. All extracted holes had an area with a CNR of ≥1.5. This quantitative method of evaluating CBCT image quality may be more useful and less time-consuming than evaluation by observation.

Comparison of Cone Beam Computed Tomography and Multi Slice Computed Tomography Image Quality of Human Dried Mandible using 10 Anatomical Landmarks.

Cone Beam Computed Tomography (CBCT) has gained a broad acceptance in dentomaxillofacial imaging. Computed Tomography (CT) is another imaging modality for diagnosis and preoperative assessments of the head and neck region. Considering the increased radiation exposure and high cost of CT, this study sought to subjectively assess the image quality of CBCT and Multi Slice CT (MSCT). A dry human mandible was scanned by five CBCT systems (New Tom 3G, Scanora, CRANEX 3D, Promax and Galileos) and one MSCT system. Three independent oral and maxillofacial radiologists reviewed the CBCT and MSCT scans for the quality of 10 landmarks namely mental foramen, trabecular bone, Periodontal Ligament (PDL), dentin, incisive canal, mandibular canal, dental pulp, enamel, lamina dura and cortical bone using a five-point scale. Significant differences were found between MSCT and CBCT and among the five CBCT systems (p<0.05) in visualization of different anatomical structures. A fine structure such as the incisive canal was significantly less visible and more variable among the systems in comparison with other anatomical landmarks such as the mental foramen, mandibular canal, cortical bone, dental pulp, enamel and dentin (p<0.05). The Cranex 3D and Promax systems were superior to MSCT and all other CBCT systems in visualizing anatomical structures. The CBCT image quality was superior to that of MSCT even though some variability existed among different CBCT systems in visualizing fine structures. Considering the low radiation dose and high resolution, CBCT may be beneficial for dentomaxillofacial imaging.

Comparison of gray values of cone-beam computed tomography with hounsfield units of multislice computed tomography: An in vitro study.

Hounsfield unit (HU) provides a quantitative evaluation of bone density. The assessment of bone density is essential for successful treatment plan. Although, multislice computed tomography (MSCT) is considered as gold standard in evaluating bone density, cone-beam computed tomography (CBCT) is frequently used in dentomaxillofacial imaging due to lower radiation dose, less complex device, and images with satisfactory resolution. The aim of this study is to determine and compare the gray value and HU value of hypodense and hyperdense structures on CBCT and MSCT, respectively. The study also evaluated and compared the gray values in different field of views within CBCT. A total of 20 dry human mandibles were obtained. The gray values and HU values of hypodense structures (extraction socket, inferior alveolar canal, and mental foramen) and hyperdense structures (enamel, cancellous, and cortical bone) were evaluated and compared between CBCT and MSCT images, respectively. The obtained data were statistically analyzed. One-way analyses of variance, ANOVA F-test. The gray value for hypodense structures in large volume CBCT scans resembled the HU value. The study showed statistically significant difference (P < 0.001) in gray values for all the hyperdense structures in CBCT when compared to HU values of MSCT scans. The gray value for hypodense structures in large volume CBCT scan was more reliable and analogous to HU value in MSCT. The determination of grey values in CBCT may not be as accurate as HU value in CT for hyperdense structures.

The Effects of Imaging Enhancement Tools in the Detection of Horizontal Root Fractures.

Detection of root fracture is challenging both clinically and radiographically. Root fractures occur in different planes with unpredictable presentations. The aim of the study was to evaluate the diagnostic accuracy of selected digital image enhancement tools in the detection of horizontal Root Fracture (RF). Fifty three roots, of single and multi-rooted teeth, in eight dentate human cadaver mandibles were selected for this study. Following minimally traumatic extraction of the teeth, horizontal fractures were induced in 23 roots and remounted in the empty sockets of their respective human dry mandibles. The remaining teeth with no fractures were used as the control group. Twenty two periapical radiographs were obtained by using the paralleling technique and using Complementary Metal Oxide Semiconductor (CMOS). Image J software was used to enhance the original images with the Inversion (IN), Histogram-Equalization (EQ) and Polynomial (Poly) tools. A total of 88 periapical images (original and three enhanced images) were reviewed independently by three Oral and Maxillofacial Radiologists and two Endodontists. Receiver Operating Characteristic (ROC) curve analysis was used to evaluate the accuracy of fracture detection and the kappa statistic was used to assess agreement among reviewers. The diagnostic accuracy for one of the observers was significantly different in detection of RF with only EQ enhancement tool. Sensitivity and specificity were not significantly different. Interobserver agreement showed no significant difference between imaging methods. Intra-observer agreement was high to moderate. There was no significant difference between the different imaging modalities. No statistical difference for the agreement was found among or between the endodontists and radiologists in this study.

Evaluation of the accuracy of linear measurements on multi-slice and cone beam computed tomography scans to detect the mandibular canal during bilateral sagittal split osteotomy of the mandible

The aim of this study was to compare the accuracy of linear measurements of the distance between the mandibular cortical bone and the mandibular canal using 64-detector multi-slice computed tomography (MSCT) and cone beam computed tomography (CBCT). It was sought to evaluate the reliability of these examinations in detecting the mandibular canal for use in bilateral sagittal split osteotomy (BSSO) planning. Eight dry human mandibles were studied. Three sites, corresponding to the lingula, the angle, and the body of the mandible, were selected. After the CT scans had been obtained, the mandibles were sectioned and the bone segments measured to obtain the actual measurements. On analysis, no statistically significant difference was found between the measurements obtained through MSCT and CBCT, or when comparing the measurements from these scans with the actual measurements. It is concluded that the images obtained by CT scan, both 64-detector multi-slice and cone beam, can be used to obtain accurate linear measurements to locate the mandibular canal for preoperative planning of BSSO. The ability to correctly locate the mandibular canal during BSSO will reduce the occurrence of neurosensory disturbances in the postoperative period.

External Cervical Resorption: A Comparison of the Diagnostic Efficacy Using 2 Different Cone-beam Computed Tomographic Units and Periapical Radiographs

IntroductionThe aim of this study was to compare the diagnostic efficacy of 2 cone-beam computed tomographic (CBCT) units with parallax periapical (PA) radiographs for the detection and classification of simulated external cervical resorption (ECR) lesions. MethodsSimulated ECR lesions were created on 13 mandibular teeth from 3 human dry mandibles. PA and CBCT scans were taken using 2 different units, Kodak CS9300 (Carestream Health Inc, Rochester, NY) and Morita 3D Accuitomo 80 (J Morita, Kyoto, Japan), before and after the creation of the ECR lesions. The lesions were then classified according to Heithersay's classification and their position on the root surface. Sensitivity, specificity, positive predictive values, negative predictive values, and receiver operator characteristic curves as well as the reproducibility of each technique were determined for diagnostic accuracy. ResultsThe area under the receiver operating characteristic value for diagnostic accuracy for PA radiography and Kodak and Morita CBCT scanners was 0.872, 0.99, and 0.994, respectively. The sensitivity and specificity for both CBCT scanners were significantly better than PA radiography (P < .001). There was no statistical difference between the sensitivity and specificity of the 2 scanners. The percentage of correct diagnoses according to the tooth type was 87.4% for the Kodak scanner, 88.3% for the Morita scanner, and 48.5% for PA radiography.The ECR lesions were correctly identified according to the tooth surface in 87.8% Kodak, 89.1% Morita and 49.4% PA cases. The ECR lesions were correctly classified according to Heithersay classification in 70.5% of Kodak, 69.2% of Morita, and 39.7% of PA cases. ConclusionsThis study revealed that both CBCT scanners tested were equally accurate in diagnosing ECR and significantly better than PA radiography. CBCT scans were more likely to correctly categorize ECR according to the Heithersay classification compared with parallax PA radiographs.

Morphometric analysis of mental foramen in human dry mandibles of nepalese population

Background: Mental foramina are located bilaterally in the antero-lateral aspect of the body of mandible. It transmits mental nerve, and vessels. The location, shape, size, direction and number of mental foramen in human mandibles are subject of variation. Aims and Objective: To establish the location, shape, size, direction and incidence of mental foramen (MF) in dry human mandibles of Nepalese population.Materials and Methods: One hundred dry human mandibles of unknown age and sex were selected randomly. Shape, size, position of MF with respect to tooth and other anatomical landmark were determined. Student paired t-test was used for specific statistical analysis.Results: In most cases (61%), the MF was oval in shape &amp; situated below the apex of second premolar (58% on right side and 69% on left side). Various parameters investigated were, the horizontal distance between (1) base of mandible and MF was 12.24 mm on right and 12.26mm on the left, (2) alveolar margin and MF was 13.95 mm on right &amp;13.75 mm on left (3) symphysis menti of mandible and MF was 26.71 mm on right and 26.49 mm on left, (4) posterior border of mandible and MF was 65.34 mm on right and 65.68mm on left.Conclusion: By the knowledge of position, shape, size, direction and distance of the mental foramen from various landmarks and the presence of the accessory foramen may be of much use to dental surgeons.Asian Journal of Medical Sciences Vol.7(5) 2016 82-86

An Anatomical Study and Clinical Correlations of Mandibular Foramen in Dry Adult Human Mandibles of North Indian Origin

An Anatomical Study and Clinical Correlations of Mandibular Foramen in Dry Adult Human Mandibles of North Indian Origin

A study on coronoid process of the dry adult human mandibles

IntroductionThe coronoid process of mandible is of great clinical significance to maxillofacial surgeons for reconstructive purposes. Its variations can result in extremely narrow vestibular space, due to close proximity of the medial aspect of coronoid process to distal molar tooth. It is suitable for paranasal augmentation with the advantages of biocompatibility, availability and reduced operation time for harvesting. The knowledge of its variations is very helpful in anthropological and forensic practice. The present study was aimed to measure various dimensions of coronoid process and its variations in human mandible. MethodThe study was conducted on hundred dry human mandibles. Following parameters of coronoid process were studied: shape, width and height at its base and relation to the condylar process. ResultsTaking into consideration of both sides, the shape of coronoid process was hooked in 54.5%, triangular in 23.5% and rounded in 18.5% of the mandibles. Variant shapes were also observed like square (0.5%), hook & round (3%). The width of coronoid process on right side ranged from 13 to 28mm with a mean of 19.30±2.9mm and on left side ranged from 10 to 28mm with a mean of 19.1±3.08mm. The height of coronoid process on right side ranged from 11 to 27mm with a mean of 18.2±3.44mm and on left side ranged from 11 to 27mm with a mean of 18.0±3.36mm. Coronoid process was higher than condylar process bilaterally in 3 mandibles. ConclusionsThe morphologic and morphometric variations of coronoid process are clinically important for dental surgeons.

Experimental Validation of Plastic Mandible Models Produced by a "Low-Cost" 3-Dimensional Fused Deposition Modeling Printer.

BackgroundThe objective of this study was to investigate the accuracy of 3-dimensional (3D) plastic (ABS) models generated using a low-cost 3D fused deposition modelling printer.Material/MethodsTwo human dry mandibles were scanned with a cone beam computed tomography (CBCT) Accuitomo device. Preprocessing consisted of 3D reconstruction with Maxilim software and STL file repair with Netfabb software. Then, the data were used to print 2 plastic replicas with a low-cost 3D fused deposition modeling printer (Up plus 2®). Two independent observers performed the identification of 26 anatomic landmarks on the 4 mandibles (2 dry and 2 replicas) with a 3D measuring arm. Each observer repeated the identifications 20 times. The comparison between the dry and plastic mandibles was based on 13 distances: 8 distances less than 12 mm and 5 distances greater than 12 mm.ResultsThe mean absolute difference (MAD) was 0.37 mm, and the mean dimensional error (MDE) was 3.76%. The MDE decreased to 0.93% for distances greater than 12 mm.ConclusionsPlastic models generated using the low-cost 3D printer UPplus2® provide dimensional accuracies comparable to other well-established rapid prototyping technologies.Validated low-cost 3D printers could represent a step toward the better accessibility of rapid prototyping technologies in the medical field.