Cone Beam CT Study Research Articles

The Frequency of Occipital Spurs in Relation to the Cephalic Index: An Anatomorphometric Cone Beam CT Study.

The occipital spur (OS) can be described as an abnormal elongation of the external occipital protuberance (EOP). The cephalic index (CI) refers to the ratio of width to length in any skull. The aim of the present study was to evaluate the frequency and types of OS. It also aimed to determine the mean CI and the distribution of skull types using cone beam computed tomography (CBCT). And to determine if there was a relationship between the cephalic index and the presence and types of OS. CBCT scans from 523 patients were included in the study. OSs were classified as type 1 (flat), type 2 (crest), and type 3 (spine). Skull length and width were measured on axial sections and the CI was calculated. Based on the cephalic index (CI), skull types were classified as dolichocephalic (CI < 75), mesocephalic (75 < CI < 80), brachycephalic (80 < CI < 85), and hyperbrachycephalic (CI > 85). The most common cranial types in the study group were brachycephalic (44.7%), mesocephalic (28.3%), hyperbrachycephalic (21.2%), and dolichocephalic (5.7%). Regarding the presence of OS, 54.3% of the participants had no OS, 23.1% had flat type, 15.3% had crest type, and 7.2% had spin type OS. There was a statistically significant difference (P < 0.05) in the frequency of OS according to skull type. This study, the first to evaluate CI and OS using CBCT, concludes that brachycephaly is the most common cranial type. OS is more common in mesocephalic and dolichocephalic skulls, at older ages, and in males.

Artificial intelligence vs. semi-automated segmentation for assessment of dental periapical lesion volume index score: A cone-beam CT study

IntroductionCone beam computed tomography periapical volume index (CBCTPAVI) is a categorisation tool to assess periapical lesion size in three-dimensions and predict treatment outcomes. This index was determined using a time-consuming semi-automatic segmentation technique. This study compared artificial intelligence (AI) with semi-automated segmentation to determine AI's ability to accurately determine CBCTPAVI score. MethodsCBCTPAVI scores for 500 tooth roots were determined using both the semi-automatic segmentation technique in three-dimensional imaging analysis software (Mimics Research™) and AI (Diagnocat™). A confusion matrix was created to compare the CBCTPAVI score by the AI with the semi-automatic segmentation technique. Evaluation metrics, precision, recall, F1-score (2×precision×recallprecision+recall), and overall accuracy were determined. ResultsIn 84.4 % (n = 422) of cases the AI classified CBCTPAVI score the same as the semi-automated technique. AI was unable to classify any lesion as index 1 or 2, due to its limitation in small volume measurement. When lesions classified as index 1 and 2 by the semi-automatic segmentation technique were excluded, the AI demonstrated levels of precision, recall and F1-score, all above 0.85, for indices 0, 3–6; and accuracy over 90 %. ConclusionsDiagnocat™ with its ability to determine CBCTPAVI score in approximately 2 min following upload of the CBCT could be an excellent and efficient tool to facilitate better monitoring and assessment of periapical lesions in everyday clinical practice and/or radiographic reporting. However, to assess three-dimensional healing of smaller lesions (with scores 1 and 2), further advancements in AI technologies are needed.

0720 A Cone Beam CT Study of Upper Airway Morphology in Perimenopausal and Postmenopausal Women

0720 A Cone Beam CT Study of Upper Airway Morphology in Perimenopausal and Postmenopausal Women

Comparative analysis of temporomandibular joint morphology in degenerative joint disease: A cone-beam CT study in patients with and without arthralgia

ObjectivesThis cross-sectional study aimed to compare, by using Cone-Beam Computed Tomography (CBCT), temporomandibular joint (TMJ) morphology among patients with degenerative joint disease (DJD) with or without arthralgia, as well as a control group. Methods: Thirty-one patients and their respective CBCT TMJ exams were assessed. These individuals were selected from an Orofacial Pain Service and classified into three groups based on the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD): group 1 (10 patients with TMJ DJD and arthralgia), group 2 (11 patients with TMJ DJD without pain), and group 3 (the control group, consisting of 10 healthy individuals without any signs or symptoms of TMD). A second examiner, who was calibrated and blinded for the patient's diagnosis, evaluated the CBCT images. Results: Group 1 showed a statistically significant association with the variables of erosion (p = 0.003) and osteophyte (p = 0.04) on the condyle surface, as well as concentric condyle position with reduced joint space (p = 0.01). The Kappa concordance index between the clinical diagnosis of DC/TMD and CBCT images was k = 0.134 (p ≤ 0.001). Conclusion: The presence of erosion, osteophyte, and concentric condyle position with reduced joint space was statistically associated with DJD and ongoing TMJ joint pain.

Comparative Analysis of the Efficacy of Various Retreatment File Systems in the Removal of Gutta-Percha in Retreatment Cases and Time Taken During the Procedure: An In Vitro Cone Beam CT Study.

Background Removing gutta-percha manually can be a challenging task, especially when addressing densely packed root-filling material, particularly in cases where resin-based sealers are employed for obturation. The use of nickel-titanium (NiTi) rotary instruments not only effectively shapes the root canal but also efficiently removes the endodontic filling from the curved canal during retreatment. Hence, incorporating rotary NiTi instruments in retreatment cases can alleviate fatigue for both patients and operators. Objectives This study aims to compare the efficacy of Neo-Endo retreatment files, R-Endo retreatment files, and K and H files in the removal of endodontic filling material. Additionally, the remnants of gutta-percha in root canals are evaluated using cone beam computed tomography (CBCT). Materials and methods A total of 60 extracted first maxillary molar teeth were selected for this study. Canal preparation was conducted using the step-back method up to an apical size of 40 K-file. The obturation process involved the use of gutta-percha points and AH Plus sealer in a lateral compaction technique. Post-operative CBCT scans were taken. The samples were randomly divided according to the retreatment files used: group I included Neo-Endo retreatment files, group II included R-Endo retreatment files, and group III included conventional K-files and Hedstroem files (H-Files). The retreatment procedure was considered complete when the last instrument easily reached the working-length range and was physically clean. A stopwatch was used to record the time taken by each file to remove the obturating material. T1 represented the total time (including irrigation and change of file) required to reach the apex, while T2 indicated the complete removal of materials from the canal with the last instrument. The overall time recorded (TT) was calculated as T1 + T2. The removal process was analyzed with CBCT scans. Results The Neo-Endo retreatment files removed the filling materials better and more quickly than the other files. Conclusions Despite the presence of residual filling material in all samples, the Neo-Endo retreatment files left the least amount of residual filling material and achieved the shortest completion time.

Mandibular Posterior Anatomic Limit for Distalization in Patients With Various Patterns of Third Molar Impactions: A Three-Dimensional Cone Beam CT (CBCT) Study.

The aim was to compare and evaluate the variation in the mandible's posterior anatomic limits (MPAL) stratified by different third molar impaction patterns utilizing cone-beam CT (CBCT) in individuals with skeletal Class III malocclusion. The sample consisted of CBCT records of 80 samples of Class III patients categorized based on the pattern of their third molar impaction. The shortest linear distances from the distal root of the second mandibular molar to the inner cortex of the mandibular body were measured at the crown level, at the cementoenamel junction (CEJ), and at the depths of 4, 6, and 8mm from the CEJ, all parallel to the posterior occlusal line. The MPAL of the four groups were compared. The Shapiro-Wilk test for normality was performed. The Kruskal-Wallis test was performed to compare the MPAL distances between the groups. Significant differences were noted between the four groups at every level. MPAL distances decreased towards apex in all the groups and was least at the 8mm root level. The greatest MPAL distances were noted in the no-impaction group followed by the horizontal. At 8mm, the MPAL were 4.2+/-1.3 in Group 3 (Control), 3.3+/-0.9 in Group 1 and 2.7+/-0.05 mm in Group 2. Though the amount of space available for distalization was greatest for the mesioangular group at the crown level, it was least at the 8mm level compared to other groups. MPAL distances were shortest at the root level in Class III patients who had mesioangularly impacted third molars and care should be taken before attempting distalization in them.

Morphometric analysis of odontoid process among Arab population: a retrospective cone beam CT study.

This study aims to evaluate the feasibility of using cone beam computed tomography (CBCT) scans to assess the odontoid process diameter in the Arab population and to determine whether one or two cortical screws can be used for treating odontoid fractures. The odontoid process of 142 individuals aged 12-75 years, including 72 males (mean age: 35.5) and 70 females (mean age: 36.2), were analyzed using CBCT scans. The sagittal and coronal CBCT views were used to evaluate the antero-posterior (AP) and transverse diameters of the odontoid process. Males had substantially bigger transverse and AP diameters of the odontoid process than females (p<0.05 & P<0.01 respectively). Among the sample, 97 individuals (67.4%) had external transverse diameter (METD) of less than 9 mm which is slightly bigger than that of Indians and 48 individuals (31.83%) had enough room for two 3.5 mm or two 2.7 mm screws as their METD was more than 9 mm like that of Greek and Turkish. Age had no significant impact on the morphometric measurements of the odontoid process. More than sixty percent of the sample had METDs of less than 9 millimeters, indicating that a single 4.5-mm Herbert screw may be suggested for fixing fractured odontoid processes in the Arab population.

A Cone Beam CT Study on the Correlation between Crestal Bone Loss and Periapical Disease

The aim of this study was to determine whether the degree of bone loss around teeth can be linked to the loss of vitality of adjacent teeth and periapical disease, which necessitates root canal treatments. Three hundred and twenty-one full maxilla cone-beam computed tomography scans were examined. The parameters investigated included the degree of crestal bone loss in relation to the cementoenamel junction, the presence/absence of apical periodontitis, and the presence/absence of root canal treatments. Out of the 2001 teeth examined, 696 (34.8%) showed evidence of crestal bone loss. The degree of crestal bone loss was classified as mild, moderate, or severe. A significant association (p < 0.001) was found between the presence of crestal bone loss around a tooth and root canal treatment of that tooth. It was found that it is more likely for teeth with crestal bone loss to be root canal treated compared to teeth with existing root canal treatment and healthy crestal bone levels. Furthermore, teeth with buccal or lingual crestal bone loss were significantly associated with a higher rate of periapical disease than teeth without crestal bone loss (p < 0.001). CBCT identified the severity of bone loss on all surfaces of the teeth, and the most common presentation was bone loss to the mid-root level. Teeth with crestal bone loss were significantly more likely to be associated with a higher rate of periapical disease. Teeth with crestal bone loss were more likely to be root treated than teeth with healthy crestal bone levels.

Investigation of Frequency of Heterotopic Teeth: A Cone Beam CT Study

Aim: Teeth that occur in distant places from the alveolar arch (maxillary sinus, orbit, infratemporal fossa, condylar region, etc.) because of various local or systemic factors are named heterotopic teeth. The heterotopic tooth is a rare phenomenon. Although the etiology is still unknown, it is known that it may be seen due to pathologies caused by cystic lesions, cleft lip-palate, trauma history, and infectious conditions. They are usually asymptomatic, so they are detected by chance in routine clinical and radiological examinations. This study aims to determine the frequency of heterotopic permanent teeth and their anatomical localization with the help of cone-beam computed tomography (CBCT).&#x0D; Methods: This study was retrospectively performed with CBCT slices. CBCT sections of 2590 individuals (1432 females, 1158 males) between the ages of 10-89 (mean: 44 ± 17 years) were evaluated in the study. Heterotopic teeth were investigated using coronal, axial, sagittal CBCT sections in regions distant from the maxillary-mandibular arch. SPSS V.21 software (IBM Corp., Armonk, NY, USA) was used for data analysis. &#x0D; Results: Heterotopic teeth were found in 10 of 2590 individuals (0.4%). All of the heterotopic teeth detected are molar teeth; 4 are mandibular third molar teeth, 5 are maxillary third molar teeth and 1 is maxillary second molar tooth. The frequency of heterotopic teeth according to gender did not show a statistically significant difference (4 females, 6 males) p&gt; 0.05. The average age of individuals with heterotopic teeth is 35.3 (17-65 years). 4 of the heterotopic impacted teeth are located in the ramus and 6 in the maxillary sinus.&#x0D; Conclusions: The prevalence of heterotopic teeth is very rare (0.4%). The teeth with the highest frequency of heterotopia are the third molars. Heterotopic teeth do not have an anatomical location and gender that they prefer predominantly.

Relationship between Maxillary Sinus Hypoplasia and Maxillary Occlusal Cant: A Cone Beam CT Study

Introduction. Maxillary sinus hypoplasia (MSH) has been reported to cause a cant in the orbital plane. No similar reports exist about the possible impact on the maxilla. The aim of this study was to assess if MSH is associated with maxillary occlusal plane (MOP) cant and if dental or mandibular factors influenced the existence of the MOP cant. Methods. 80 cone beam CT images of subjects with MSH were analyzed for the type of MSH, degree of MOP cant, open or cross bite, mandibular asymmetry, and degenerative joint disease of the temporomandibular joints. The subjects were compared with a control group matched by age and gender. Results. The degree of MOP cant (range 0–5.1°) was not statistically significantly different in unilateral vs. bilateral MSH or between the different types of MSH. The frequency of open bite, crossbite, mandibular asymmetry, or degenerative joint disease in unilateral vs. bilateral MSH or between the different types of MSH was not statistically significantly different. Between the case and control, there was no statistically significant difference in the degree of MOP cant ( 1.3 ± 1.1 ° vs. 1.1 ± 0.9 ° , respectively) or frequency of dental and mandibular factors. There was low positive linear correlation between MOP cant and mandibular symmetry in MSH subjects (Spearman’s rho = 0.23 ) and controls (Spearman’s rho = 0.18 7). Conclusions. The data suggests a view of the alveolar bone as the adaptable skeletal unit to ensure and bridge the functionality between the nasomaxillary complex and TMJ system–two systems with very different function, and therefore largely independent “matrix units.”

Frequency and anatomic variability of the mandibular lingual foramina: a cone-beam CT study

BackgroundTo evaluate the distribution of lingual foramina (LF) and their correlation with demographic characteristics and mandible width, shape, and bone thickness in Caucasian Italian patients subjected to cone-beam CT (CBCT).MethodsCBCTs were reviewed to assess the number of all LF, midline and lateral LF. We also assessed the relationship of the number of lateral LF with gender and mandibular width, shape, and bone thickness using the Chi Square test. A p value < 0.05 was considered statistically significant.Results Three-hundred patients (180 males; age range: 21–87 years) were included. The highest frequency per patient was of 2 LF (97/300, 32.3%), followed by 3 (81/300, 27%) and 4 (53/300, 17.7%). No LF were observed in 2/300 patients (0.7%), while the highest number was of 8 LF in one patient. The highest frequency of midline LF per person was of 2 LF (57.3%, 172/300), while the highest number per person was 5 LF in one patient (0.3%). The highest frequency of midline LF located above and below the genial tubercle was of 1 in 197/300 patients (65.7%) and in 169/300 patients (56.3%), respectively. Concerning lateral LF, the highest frequencies were of 0 (113/300, 37.7%) and of 1 (112/300, 37.3%). We did not observe any significant difference of the number of midline and lateral LF based on gender (P = .438 and P = .195, respectively) or mandible width (P = .069 and P = .114, respectively). The mandible shape was normal in 188 cases, with facial constriction in 42, lingual constriction in 54, and hour glass constriction in 16. The mean bone thickness was 10.76 mm in the symphysis, 10.92 mm in the right hemiarches, and 10.68 in the left hemiarches. No significant differences in the distribution of LF were observed also based on mandibular shape and bone thickness (both with P > .05).ConclusionsWe have shown the high variability of number and anatomic distribution of LF in an Italian group of patients subjected to CBCT without reporting any association with gender and mandible width, shape, and bone thickness.

A Cone Beam CT Study of Upper Airway Morphology in Perimenopausal and Postmenopausal Women.

PurposeMenopause is accompanied by a decline in estrogen and progesterone. Several studies have demonstrated that upper airway patency decreases in women after menopause, while morphology changes are still a lack of evidence. This study aimed to explore upper airway morphology changes in perimenopausal and postmenopausal women.MethodsThis retrospective cross-sectional study included 367 consecutive Chinese female patients over 25 years old who had routinely taken large-field cone beam computed tomography in the imaging library of Peking University School and Hospital of Stomatology from October 2016 to September 2020. A total of 283 males were screened as sex controls according to the same age group. Upper airway morphology, hyoid position and facial pattern were measured. The association between perimenopausal and postmenopausal years and upper airway morphology in both sexes was analyzed.ResultsPerimenopausal women (aged 45–54 years) showed a significant decrease in the volume (3172.91mm3, 95% CI = 653.86–5691.96) and minimum cross-sectional area (37.08 mm2, 95% CI = 5.36–68.80), and a significant increase in the length (−1.96mm, 95% CI = −3.62 to −0.29) of upper airway compared to adjacent reproductive years (aged 35–44), while this difference was neither seen in other adjacent two reproductive age groups of females nor in the same age groups of males. In postmenopausal women (55 years and older), hyoid position was significantly lower (−2.74mm, 95% CI = −4.42 to −1.07) than either age group, while no similar changes were seen in men.ConclusionWomen had smaller airway volume, reduced upper airway cross-sectional area and longer airway length in perimenopausal years, and a significantly lower hyoid position in postmenopausal years. These changes may be related to menopause itself and independent of the changes associated with aging.

Intelligent quantitative assessment of skeletal maturation based on multi-stage model: a retrospective cone-beam CT study of cervical vertebrae.

To develop new logistic regression estimative models of the cervical vertebral maturation index (CVMI) based on cone-beam CT (CBCT)-derived parameters for intelligent evaluating skeletal maturation. From 231 CBCT volumes (age range 7-17, mean age 11.09years), 154 were randomly selected to produce 2D sagittal projections of the second to fourth cervical vertebrae (C2-C4). From 19 quantitative parameters, significant predictors were deduced to formulate logistic models. Using the CVMI and significant predictors of 77 other subjects, performance of the models was externally examined by direct comparison and the area under the receiver operating characteristic curve (AUC). Models were modified if required, to improve their accuracy. Chronological age, C3 height ([Formula: see text], and ratio of posterior height to lower width of C4 [Formula: see text] were entered as significant predictors. Accuracy of the models was acceptable (total AUC = 0.91) except for 4th and 5th stage (AUC of 0.82 and 0.83, respectively), which were mis-predicted inversely. Adjusted models were generated by bivariate logistic regression analysis and adding significant parameters ([Formula: see text] and [Formula: see text], with odds ratios of 3.308 and 3.38, respectively) from 58 subjects in 4th and 5th stages of CVMI in the model establishment group. The total AUC increased to 0.94, along with an increase in the accuracy of the latter optimized models to 77.9 and 87%, respectively. The new intelligent models reliably estimated skeletal maturation and can be utilized in the clinical field or machine learning-based skeletal maturation assessment.

Distortion or magnification? An in vitro cone-beam CT study of dimensional changes of objects with different compositions.

To assess whether dimensional changes occur as shape distortion (unevenly), contraction or magnification (evenly) in cone beam computed tomography (CBCT) considering materials, anatomical regions and metal artefact reduction algorithms. Four cylinders of amalgam (Am), cobalt-chromium (Co-Cr), gutta-percha (Gu), titanium (Ti) and zirconium (Zi) were inserted inside a polymethylmethacrylate phantom in anterior and posterior regions for acquisitions in Picasso Trio and OP300 with MAR enabled and disabled. Two observers measured the dimensions of each cylinder in three axes: Y (height), Z (antero posterior diameter) and X (latero-lateral diameter). Repeated measures ANOVA with Tukey post-hoc test compared the data (α = 5%). Shape distortion occurred for all materials in anterior region of Picasso Trio without MAR (p < 0.05). With MAR enabled, Gu and Ti contracted (p ≥ 0.05), while the others showed distortion (p < 0.05). In posterior region, all materials distorted in both MAR conditions (p < 0.05), except Gu, which magnified without MAR (p ≥ 0.05) and contracted unevenly with MAR (p < 0.05). In anterior region of OP300, all materials magnified without MAR, (p ≥ 0.05) and had shape distortion with MAR (p < 0.05). In posterior region, only Am showed magnification without MAR (p ≥ 0.05), while all materials presented shape distortion with MAR (p < 0.05). Dimensional changes of high-density materials in CBCT can be either a magnification, a contraction or a distortion; the last condition is the most prevalent. Furthermore, changes differ considering material, anatomical region and MAR condition.

Prevalence of maxillary sinus hypoplasia and association with variations in the sinonasal complex: a cone beam CT study.

Understanding of maxillary sinus hypoplasia (MSH) and associated sinonasal variants is paramount to the diagnostic and therapeutic success of maxillary sinus and maxillary dental implant surgery. The purpose of this work was to explore the prevalence of MSH, frequency of mucosal thickening, and anatomical variations in the sinonasal complex. Retrospective case-control design based on cone beam CT images of dental patients with MSH and matched for age and gender. MSH type and sinonasal variables were recorded. One thousand three hundred seventy cone beam CT scans were analyzed for MSH. MSH prevalence was 6% (n=82), matched with 82 controls= 100 females and 64 males, mean age 37.1±14.1 years. Most MSH were type I, 69.5%, 80.5% unilateral, 65.9% associated with no or mild mucosal thickening. Associated sinonasal anatomical variations were <27% except for deviated/hyperplastic (DH) meatus, 48.8%. Within the MSH group, significant associations were presented between MSH type, mucosal thickening, and DH nasal meatus. MSH group vs controls showed a significant difference in mucosal thickening (OR 5.2, 95% CI 2.0-17.3) and DH meatus (OR 1.6, 95% CI 1.4-2.1). A hypoplastic maxillary sinus with abnormal or absent uncinate process is associated with advanced mucosal thickening and may present with altered anatomy of the lateral wall of the nasal cavity causing its approximation to the orbital floor. Pre-surgical knowledge of altered anatomy in the sinonasal complex is crucial in dental implant or sinus surgery.

Prevalence and morphological characteristics of disto-lingual roots in mandibular first molars: a cone beam CT study with diagnostic and therapeutic implications.

High prevalence of disto-lingual roots (DLR) at the mandibular molar in Chinese can complicate the management of periodontitis. This study assessed the prevalence and morphological features of mandibular first molar DLR and furcation entrances in a Hong Kong population by analysis of cone beam computed tomography (CBCT). CBCT including the mandibular 1st molar region were identified from the Prince Philip Dental Hospital archive and analyzed by a single investigator. Morphologic features and location of DLR were studied and presented as 95% confidence intervals. A total of 398 CBCTs with 716 mandibular first molars were analyzed. The prevalence of DLRs in mandibular first molars on subject based was 20.1% (95% C.I. 16.2-24%). DLR was located 44.5° ± 8.9° (95% C.I. 42.8-46.1°) to the mid-lingual of the mandibular first molar, with a bucco-lingual width 3.3 mm ± 0.5 mm (95% C.I. 3.2-3.4 mm). The mesial furcation entrance was located 4.0 mm ± 0.9 mm (95% C.I. 3.8-4.2 mm) apical to the cemento-enamel junction (CEJ) while the distal was 5.2 mm ± 1.3 mm (95% C.I. 5.0-5.4 mm) from the CEJ. The surface area of the DLR was 106.9 mm2 ± 41.2 mm2 (95% C.I. 98.9-114.8 mm2). Chinese population has a high prevalence of DLRs. The present information is critical for understanding the morphological features of DLR and guide diagnosis and treatment of stage III periodontitis as well as for secondary prevention and supportive care of stage II periodontitis. Little is known about the location and morphology of disto-lingual roots of mandibular 1st molars, yet they are frequently present in patients with Chinese ethnic background, thus complicating diagnosis and treatment. The present study utilized CBCT to analyze the prevalence and morphological features of the mandibular first molar DLR and furcation entrance. It is the first study reporting on the position of the DLR, degree of separation of the furcation, and the surface area of the DLR.

The mandibular incisive foramen, a false mental foramen

The mandibular incisive foramen (MIF) is an opening on the external surface of the dentate mandibular body, medial to, and facing the mental foramen (MF). There is actually scarce evidence of such MIF. A retrospective Cone Beam CT (CBCT) study of the archived files of a 56 y.o. male patient was documented anatomically for dental medical purposes. In the 2nd premolar region of the left hemimandible were found two adjacent foramina facing one each other: the distal one was opened medially, while the medial one was oriented distally. On axial CBCT slices the mandibular canal was detected to open at the distal foramen in the outer cortical plate of the mandible. The medial foramen in that cortical plate served as entrance to the mandibular incisive canal, thus being a MIF. CBCT accurately distinguishes the canals opening on the outer cortical plate of the mandible thus is of use to differentiate a MIF from a MF. Such adjacent foramina expose at risk not just the mental nerve, as in cases with true multiple MF, but also the IAN and the mandibular incisive nerve.

Influence of windowing and metal artefact reduction algorithms on the volumetric dimensions of five different high-density materials: a cone-beam CT study.

To assess the influence of windowing and metal artefact reduction (MAR) algorithms on the volumetric dimensions of high-density materials using two CBCT systems. Four cylinders of amalgam, cobalt-chromium, gutta-percha, titanium and zirconium, were manufactured and their physical volumes (PV) were measured. A polymethyl methacrylate phantom containing the cylinders was submitted to CBCT acquisitions with Picasso Trio and OP300 units with their MAR enabled and disabled. The tomographic volume (TV) of all the cylinders was obtained by semi-automatic segmentation using two windowing adjustments: W1-large window width and upper window level; W2-narrow window width and low window level. Volumetric distortion was expressed as the difference between TV and PV. Statistics comprised intraclass correlation coefficient (ICC) and analysis of variance (ANOVA) for repeated measures with Tukey post hoc test (α = 5%). The ICC values ​​indicated excellent reproducibility of TV. Gutta-percha and titanium resulted in the smallest volumetric distortion. Using W1 provided less volumetric distortion for almost all experimental conditions (p < 0.05). Activating MAR algorithm of Picasso Trio underestimated gutta-percha and titanium TV (p < 0.05) and was inefficient in significantly reducing the volumetric distortion of the other materials (p > 0.05). Disabling MAR algorithm of OP300 resulted in smaller volumetric distortion for almost all experimental conditions (p < 0.05). The TV of gutta-percha and titanium were closer to the PV. In general, the MAR algorithms of both systems were inefficient in significantly reducing the volumetric distortion of high-density materials. We encourage the use of large window width and upper window level to evaluate high-density materials.

Do upper third molars provide more accurate age estimation in the adult based on the pulp-to-tooth ratio than lower third molars? A cone-beam CT study

IntroductionAge-at-death estimation is an essential part of the identification process of individuals in many forensic dentistry cases where identity of the individual cannot be resolved by visual recognition or other means. Dental age estimation in adults is more of a challenge as most teeth complete their development by the age of 18 years. AimThis study aims at using the mesio-distal (MD) pulp-to-tooth ratio taken at the cervix of upper third molars (UM3) to estimate age at the time of radiographic imaging. Materials and MethodsA set of 135 Cone-beam computed tomography (CBCT) radiographs of UM3s for a random sample of 135 Jordanian adults (65 females, 70 males; age range = 18–63 years, mean age = 34.4 years, SD = 11.2 years) were used. Both pulp and tooth MD diameters were measured at the cervix. MD pulp-to-tooth ratios for UM3s were correlated with age. ResultsStatistically significant negative moderate correlation was found between the age of the individual and the cervix MD pulp/tooth ratio (r = −0.516). This indicates that only 26.6% of the variation in age can be explained by the cervix MD pulp-to-tooth ratio. ConclusionsThis study concludes that cervix MD pulp-to-tooth ratio of UM3s, although apparently stronger than that of lower M3s (r = −0.361), is not a sufficiently reliable estimator of age in adults, and this is perhaps attributed to the greater variability in the time line of third molars development.

Effect of calibration of a medical review monitor on the visibility of mandibular canal at dental implant sites: A cone beam CT study.

The aim of this study was to assess the visibility of mandibular canal (MC) on cone beam CT (CBCT) images using a medical review monitor under two different calibration modes. The effect of age, gender, and location of the dental implant site was also assessed. CBCT images of 428 dental implant sites were selected for the study. Images were displayed twice on a medical review monitor using two different calibration modes: standard and DICOM, and two observers evaluated the visibility of the MC using four-point scoring scale (1-4, poor to excellent). Cohen Kappa was used to assess intra and inter-rater reliability. Chi-square test was used to compare proportions of MC visibility by gender and location and one-way ANOVA was used to compare mean age and MC visibility. Each observer classified the visibility of MC with a total agreement of 100% between DICOM mode and standard mode (Kappa = 1, P < 0.001 for each observer). In each mode, a strong agreement (inter-rater reliability) was detected between the observers (Cohen's kappa = 0.88 for both modes, P < 0.001) with a percent agreement of 95.3% for each mode. Gender and location were not statistically associated with MC visibility (P > 0.05). Age, however, was a significant predictor of MC visibility (P < 0.05). DICOM calibration had no added value over standard calibration for assessing the visibility of MC at dental implant sites on a medical review monitor. Only the age had significant effect on the visibility.