3D Cone Beam Research Articles

Cranio-cervical abnormalities in moderate-to-severe osteogenesis imperfecta - Genotypic and phenotypic determinants.

Cranio-cervical anomalies are significant complications of osteogenesis imperfecta (OI), a rare bone fragility disorder that is usually caused by mutations in collagen type I encoding genes. To assess cranio-cervical anomalies and associated clinical findings in patients with moderate-to-severe OI using 3D cone beam computed tomography (CBCT) scans. Cross-sectional analysis of CBCT scans in 52 individuals with OI (age 10-37 years; 32 females) and 40 healthy controls (age 10-32 years; 26 females). Individuals with a diagnosis of OI type III (severe, n = 11), type IV (moderate, n = 33) and non-collagen OI (n = 8) were recruited through the Brittle Bone Disorders Consortium. Controls were recruited through the orthodontic clinic of the University of Missouri-Kansas City (UMKC). OI and control groups were similar in mean age (OI: 18.4 [SD: 7.2] years, controls: 18.1 [SD: 6.3] years). The cranial base angle was increased in the OI group (OI: mean 148.6° [SD: 19.3], controls: mean 130.4° [SD: 5.7], P = .001), indicating a flatter cranial base. Protrusion of the odontoid process into the foramen magnum (n = 7, 14%) and abnormally located odontoid process (n = 19, 37%) were observed in the OI group but not in controls. Low stature, expressed as height z-score (P = .01), presence of DI (P = .04) and being male (P = .04) were strong predictors of platybasia, whereas height z-score (P = .049) alone was found as positive predictor for basilar impression as per the Chamberlain measurement. The severity of the phenotype in OI, as expressed by the height z-score, correlates with the severity of cranial base anomalies such as platybasia and basilar impression in moderate-to-severe OI. Screening for cranial base anomalies is advisable in individuals with moderate-to-severe OI, with special regards to the individuals with a shorter stature and DI.

Influence of a Metal Artifact Reduction Filter on the Diagnostic Accuracy of Complete and Incomplete Vertical Root Fractures

IntroductionThis study aimed to assess the influence of the e-vol DX BAR filter on the diagnostic accuracy of complete and incomplete vertical root fractures (VRFs). MethodsTwenty single-rooted teeth were selected. The tooth crowns were removed, and the root canals were prepared up to a 40/.06 instrument (ProTaper Next). Each specimen was scanned in a Prexion 3D cone-beam computed tomography (CBCT) device, in a dry human skull, in 4 different situations: no root canal filling, gutta-percha, fiberglass post, and metal post. The specimens were fractured in a universal testing machine by using a customized wedge. Each specimen was reinspected to confirm the presence of incomplete VRFs. Another set of CBCT scans was performed. Then, the fractures were completed in the universal testing machine, the teeth were reinspected, and the CBCT images were acquired again. Images were assessed by using the e-Vol DX software system, with the BAR filter and with the original images, for the diagnosis of VRFs. Statistical analysis was performed by using the DeLong and McNemar tests for the comparison of the area under the receiver operating characteristic curves (AUC), accuracy, sensitivity, and specificity values. ResultsThe use of the BAR filter did not improve the diagnostic values of AUC, accuracy, sensitivity, and specificity in both fracture patterns (P > .05). Incomplete VRFs presented significantly lower AUC, accuracy, and sensitivity compared with complete VRFs (P < .0001). ConclusionsThe BAR filter did not improve the diagnostic accuracy of VRFs. The intracanal materials also did not influence the diagnosis. Incomplete VRFs were highly associated with a decrease in sensitivity.

X-ray source arrays for volumetric imaging during radiotherapy treatment

This work presents a novel hardware configuration for radiotherapy systems to enable fast 3D X-ray imaging before and during treatment delivery. Standard external beam radiotherapy linear accelerators (linacs) have a single X-ray source and detector located at ± 90° from the treatment beam respectively. The entire system can be rotated around the patient acquiring multiple 2D X-ray images to create a 3D cone-beam Computed Tomography (CBCT) image before treatment delivery to ensure the tumour and surrounding organs align with the treatment plan. Scanning with a single source is slow relative to patient respiration or breath holds and cannot be performed during treatment delivery, limiting treatment delivery accuracy in the presence of patient motion and excluding some patients from concentrated treatment plans that would be otherwise expected to have improved outcomes. This simulation study investigated whether recent advances in carbon nanotube (CNT) field emission source arrays, high frame rate (60 Hz) flat panel detectors and compressed sensing reconstruction algorithms could circumvent imaging limitations of current linacs. We investigated a novel hardware configuration incorporating source arrays and high frame rate detectors into an otherwise standard linac. We investigated four potential pre-treatment scan protocols that could be achieved in a 17 s breath hold or 2–10 1 s breath holds. Finally, we demonstrated for the first time volumetric X-ray imaging during treatment delivery by using source arrays, high frame rate detectors and compressed sensing. Image quality was assessed quantitatively over the CBCT geometric field of view as well as across each axis through the tumour centroid. Our results demonstrate that source array imaging enables larger volumes to be imaged with acquisitions as short as 1 s albeit with reduced image quality arising from lower photon flux and shorter imaging arcs.

The Accuracy and Stability of Intentional Change of Frontal-Ramal Inclination in Orthognathic Surgery for Facial Asymmetry Patients.

Facial asymmetry can be defined as differences in the left and right sides of the face, and most of the patients with facial asymmetry have different left and right frontal-ramal inclinations (FRIs). Restoring the symmetry of both FRIs is important in the surgery of facial asymmetry patients, but it is very difficult to achieve perfect symmetry through conventional orthognathic surgery. However, by using 3-dimensional (3D) virtual planning and CAD/CAM technolo gies, intentional change of FRIs can be possible so the symmetry can be improved. The purpose of this study is to evaluate the surgical accuracy and long-term stability of intentional change of FRIs by 3D virtual surgery, CAD/CAM-assisted orthognathic surgery for patients with facial asymmetry. The study included 20 patients who had undergone orthognathic surgery for skeletal class III malocclusion from January 2019 to December 2021. To evaluate the accuracy of surgery, 3D facial cone beam computed tomography (CBCT) taken immediately after surgery (T1) and virtual surgery data (Tv) were measured and the difference values were calculated. The evaluation of the long-term stability of intentional change of FRI was performed by measuring T1 and T2 (3D facial cone beam computed tomography images taken 6mo after surgery) and the difference values were calculated. The difference values of FRIs in the left and right proximal segments of each patient were calculated. And then, for comparison depending on the direction of rotation, increased FRI groups (n=20, medial rotation) and decreased FRI groups (n=20, lateral rotation) were analyzed separately. As a result, all difference values at both (ΔT1-Tv) and (ΔT2-T1) were <1 degree. As a result of analyzing the entire FRI by dividing it into decreasing and increasing groups, the mean value of (ΔT1-Tv) was 0.225 degrees for the decreasing group and 0.275 degrees for the increasing group. It means that the proximal segment moved less than the movement implemented by the virtual surgery through actual surgery but it shows a very small error, which means that the overall operation almost accurately implements the virtual surgical planning. Compared with (ΔT1-Tv), the mean value of (ΔT2-T1) showed a much smaller error value, and no specific tendency was observed. This indicates that the stability after surgery is very good. Based on this study, using 3D virtual surgery planning and CAD/CAM technologies for treating patients with facial asymmetry was very useful, and surgery could be performed accurately and predictably. In particular, left-right symmetry was almost perfectly achieved through virtual simulation and could be implemented through actual surgery. Therefore, it can be said that the use of these 3D technologies is recommended for the surgical approach of facial asymmetry.

Clinical aspects and cytomorphological and functional features of the nasal mucosa in chronic pathology of the intranasal structures and their verification from CT data

Background. Approximately 30% of the general human population suffers from chronic pathology of intranasal structures, the main manifestations of which are impaired nasal breathing and sense of smell. The main instrumental diagnostic methods for this pathology are X-ray computed tomography (CT), which allows obtaining data on the architecture of the anatomical structures of the upper respiratory tract, and rhinomanometry, based on the results of which it is possible to assess the functional capacity of the nasal cavity during breathing. Also, a thorough study of the cytological material of the mucous membrane of the upper respiratory tract is an important component in determining the functional state of the nasal cavity, clarifying the diagnosis and choosing a treatment method. This allows the doctor to determine the composition and number of cellular elements in the material, assess their condition (destruction, proliferation, dystrophy, necrosis, etc.), ascertain the intensity of the body’s reactive abilities, monitor the dynamics of tissue recovery or the healing process in them, and encourages researchers to study in more detail and comparing the materials of clinical, radiological and cytological studies with the aim of developing a pathogenetically directed complex treatment of patients with nasal breathing disorders. Therefore it is necessary to know aspects of correlation between the results of rhinocytography and CT data in typical pathological conditions with nasal congestion are considered. Purpose – is to study the clinical aspects and cytomorphological and functional features of the nasal mucosa in patients with pathology of intranasal structures with respiratory and olfactory disorders and research their independent verification based on the CT data. Materials and Methods. Clinical examination of patients included the study of complaints, anamnesis of the disease, examination of the ENT organs, rhinomanometry, endoscopic examination of the nasal cavity and nasopharynx, The CT of the paranasal sinuses using 3D cone beam tomography on the Vatech PaX-i3D device, as well as cytological examination of the nasal mucosa. The criteria for participation in the study were the absence of chronic diseases of the cardiovascular, respiratory, digestive, urinary systems, as well as heredity burdened by these diseases. Results. Formation of a different nature of the course and severity of disorders is associated with inflammatory, dyscirculatory and trophic disorders in the nasal mucosa, which weaken both mucociliary clearance and local immunity. This applies mainly to the I group of observations. The consequence of a decrease in local immunity factors in the nasal mucosa is microbial contamination, which is associated with a long-term nasal breathing disorder in the I and II groups of observations, up to five years and six months, respectively. The results of rhinocytography mostly correspond with the aerodynamic models data of nasal сavity from the CT datasets. Conclusions. Despite the reliability of the examinations carried out by us, the cytological examination of the nasal mucosa is only an additional analysis, the interpretation of which should be based on the clinical picture of a particular patient. Proposed aerodynamic model from CT-datasets actually provides an independent verification of the aerodynamic characteristics of the nasal cavity, obtained from rhinomanometry data, and may indicate a violation of nasal breathing according to changes in the internal anatomical configuration of the nasal chanel.

Assessing the Efficacy of Planmeca ProMax® 3D Cone-Beam CT Machine in the Detection of Root Fractures With Varied Metal Artifact Reduction Settings and Three Kilovoltage Peak Levels

This study aims to examine the accuracy of cone-beam computed tomography (CBCT) machines in detecting root fracture when using different metal artifact reduction (MAR) settings at different kilovoltage peak (kVp) levels. Sixty-six tooth roots were treated endodontically using a standardized technique. Of these, 33 roots were randomly selected to be fractured; the other 33 roots were intact and used as controls. The roots were placed randomly in prepared beef ribs to mimic the alveolar bone. Imaging was performed by Planmeca ProMax® 3D (Planmeca, Helsinki, Finland) using different MAR settings (no, low, mid, and high) at three different levels of kVp: 70, 80, and 90. Sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) were calculated. There was a significant difference in accuracy when using different MAR settings within the group of 70 kVp. Likewise, within the group of 90 kVp. There was no significant difference between different MAR settings at 80 kVp. Using low MAR/90 kVp had significantly higher accuracy relative to other MAR settings at 90 kVp; it also had the highest values of sensitivity, specificity, and AUC in the study. Using mid and high MAR at 70 kVp or 90 kVp decreased accuracy significantly. Mid MAR/90 kVp was the least effective setting in this study. Using low MAR at 90 kVp significantly increased the accuracy within the group of 90 kVp. In contrast, mid MAR and high MAR in70 and 90 kVp, respectively, decreased accuracy significantly.

In vivo Comparison of Volume of Interest Determination on Maxillary Bone Regeneration in Orthodontic Treatment: Cone-Beam Computed Tomography Versus Micro-Computed Tomography

Orthodontic treatment can result in relapse, side effects associated with Orthodontic Tooth Movement (OTM) are root resorption, bone loss, and gingival inflammation which impairs long-term stability during orthodontic treatment. OTM creates a gap causing relapse after orthodontic treatment. Regenerate bone to prevent relapse after orthodontic treatment. Volume of interest (VOI) measurement by (3 Dimension) 3D imaging Cone-beam computed tomography (CBCT) or Micro-computed tomography (Micro-CT) in vivo. In vivo tests were carried out on 6 Wistar rats aged 5 months and performed 10gf maxillary Molar 1 (M1) withdrawal with 0.010 inch Nickel-Titanium (NiTi) and 8 mm close coil spring, maxillary separation was carried out by CBCT and Micro-CT tests. The tensile force of the orthodontic appliance in the compressed and tense area is a characteristic of OTM causing changes in remodeling. Alveolar bone displacement can occur when tooth roots move through the alveolar cortical bone occurring during OTM. Measurements on samples from CBCT and Micro-CT to investigate the accuracy and reproducibility of landmarks. CBCT resolution 0.0131 µm / pixel and Micro-CT 5.7 µm/pixel, Micro-CT can determine VOI boundaries. Comparison of VOI from CBCT and Micro-CT showed VOI CBCT 9.99% and VOI Micro-CT 22.22%. 3D Micro-CT visualization is more detailed than CBCT, so VOI can be determined easily and more accurately. Detailed, clear, and accurate 3D Micro-CT visualization in the determination of VOI versus CBCT.

COMPARATIVE CEPHALOMETRIC AND 3D CONE BEAM COMPUTED TOMOGRAPHY ANALISIS OF ALVEOLAR BONE DESTRUCTION FOR TEETH IN ANTERIOR CROSSBITE

Purpose: To assess the degree of bone destruction for teeth in anterior crossbite by means of 3D cone beam computed tomography and lateral cephalometry. Material/methods: 20 patients with anterior crossbite underwent 3D cone beam computed tomography and lateral cephalometry of the anterior segments of the maxilla and mandible. The destruction of the bone in the anterior segments of the maxilla and mandible was measured (vestibularly and lingually)– the distance from the cemento-enamel junction to the top of the alveolar bone. The parameters of bone resorption for teeth 21 and 31 on cephalogramsand 3D computed tomography images were compared. For both incisors, the mean value registered by means of cephalometry was slightly higher than that registered with 3D. Results: The total mean value of bone destruction for anterior teeth was significantly higher vestibularly compared to lingually, both for the maxilla (p = 0.030) and mandible (p = 0.030). Significantly higher mean values ​​of bone destruction were found in the mandible compared to the maxilla. For both incisors (21 and 31), the mean value of resorption recorded by cephalometry was slightly higher than that recorded by 3D cone beam computed tomography, but without statistical significance. Conclusion: We found significantly higher values ​​of vestibular bone destruction compared to lingual bone destruction. Bone destruction in the mandible reached a significantly higher level than that in the maxilla. No statistically significant difference was found between the mean values ​​of bone destruction measured by means of cephalometry and 3D cone beam computed tomography.

A mixed reality-based navigation method for dental implant navigation method: A pilot study

This in vitro study aimed to put forward the development and investigation of a novel Mixed Reality (MR)-based dental implant navigation method and evaluate implant accuracy. Data were collected using 3D-cone beam computed tomography. The MR-based navigation system included a Hololens headset, an NDI (Northern Digital Inc.) Polaris optical tracking system, and a computer. A software system was developed. Resin models of dentition defects were created for a randomized comparison study with the MR-based navigation implantation system (MR group, n = 25) and the conventional free-hand approach (FH group, n = 25). Implant surgery on the models was completed by an oral surgeon. The precision and feasibility of the MR-based navigation method in dental implant surgery were assessed and evaluated by calculating the entry deviation, middle deviation, apex deviation, and angular deviation values of the implant. The system, including both the hardware and software, for the MR-based dental implant navigation method were successfully developed and a workflow of the method was established. Three-Dimensional (3D) reconstruction and visualization of the surgical instruments, dentition, and jawbone were achieved. Real-time tracking of implant tools and jaw model, holographic display via the MR headset, surgical guidance, and visualization of the intraoperative implant trajectory deviation from the planned trajectory were captured by our system. The MR-based navigation system was with better precise than the free-hand approach for entry deviation (MR: 0.6914 ± 0.2507 mm, FH: 1.571 ± 0.5004 mm, P = 0.000), middle deviation (MR: 0.7156 ± 0.2127 mm, FH: 1.170 ± 0.3448 mm, P = 0.000), apex deviation (MR: 0.7869 ± 0.2298 mm, FH: 0.9190 ± 0.3319 mm, P = 0.1082), and angular deviation (MR: 1.849 ± 0.6120°, FH: 4.933 ± 1.650°, P = 0.000).

Evaluation of Clinical Efficacy Between Forsus and Advansync Fixed Functional Appliance for the Treatment of Skeletal Class II Malocclusion Using 3D Cone Beam Computed Tomography (CBCT): A Prospective Randomized Clinical Trial.

The objective is to assess and compare whether AdvanSync gives better skeletal, dental, and soft tissue outcomes than Forsus fixed functional appliance in post-pubertal skeletal Class II malocclusion patients. A prospective study was conducted using 3D-CBCT of patients taken before and after fixed functional appliance therapy. The sample consisted of 16 patientsdivided into two groups: Group 1 was treated with Forsus and group 2 with AdvanSync appliance. All subjects were in their post-pubertal growth phase. Treatment changes were evaluated between the study groups using 12 angular and 14 linear parameters. The data were subjected to statistical analysis. Statistically significant changes in SNB(P:0.04) and ANB (P:0.01) in Forsus appliance andAdvanSync (SNB, P:008), (ANB, P: <0.001)were found between the pre and post-fixed functional appliance protocol. The effective mandibular length increased in both groups Forsus(P-value: 0.01) and AdvanSync (P-value: 0.01). Group 1 resulted in lower incisor proclination and intrusion, a reduction in an overbite, whereas group 2 resulted in lower incisor proclination, upper incisor extrusion, and retroclination. Both groups showed significant improvement in the molar relation and overjet. An increase in the total facial convexity was shown in group 1; group 2 showed an increase in the facial convexity and total facial convexity. There was no statistically significant differencebetween the effects of the Forsus and Advansync appliance groups in the post-fixed functional period. Both groups presented similar results. Forsus and Advansync appliances are effective with similar results in normalizing skeletal Class II malocclusion in post-pubertal patients. There was no statistically significant difference between the groups using Forsus or AdvanSync. Thechanges were minimal - mandibular skeletal effects, majorly dentoalveolar effects, and mild soft tissue effects.

Komparativna analiza dve metode prezervacije postekstrakcione alveole - pilot-studija

Objective. Volumetric changes of the residual alveolar ridge begin after tooth extraction. They are more pronounced in the vestibule-oral aspect than in the coronary-apical aspect. In order to preserve the volume of hard and soft tissues, several types of bone grafts, bone substitutes and biomaterials have been used. PRF (Platelet Rich Fibrin) as an autologous blood derivative has been used in recent years as a solo graft material or in combination with other graft materials. The aim of this study was clinical and radiological evaluation of two different methods of socket preservation. Methods. Two study groups of 10 subjects each, one with socket preservation with solo PRF and the other with PRF+xenograft. Dimensional changes after 4 and 6 months, density of the newly formed bone after 4 months with CBCT 3D (cone beam computed tomography) imaging technique, postoperative morbidity during the first 7 days after intervention were evaluated. Results. Statistical analysis confirmed lower bone resorption in the PRF+GRAFT test group compared to the PRF group. Better density of the newly formed bone was found in the PRF+GRAFT group and better ratio between the density in the socket and the density in the periapical region. Postoperative morbidity decreased in both groups. Conclusion. Recommendation for the use of PRF as an adjuvant with other grafts and substitutes, as well as a solo graft material.

Comparative Cone Beam Computed Tomographic Evaluation of Conventional and Conservative Endodontic Access Cavity Designs on Pericervical Dentin Thickness and Fracture Resistance of Teeth: An In-vitro Study

Introduction: The concept of ‘extension for prevention’ accelerates treatment processes but eliminates precious dentin at the pericervical area, resulting in biomechanically weakened tooth structure after endodontic treatment. Pericervical Dentin (PCD) is a new paradigm for endodontic success supports the idea that the amount of residual tooth structure is closely associated with long-term retention of the tooth and resistance to fracturing. Aim: To determine the impact of two endodontic access cavity designs and biomechanical preparation on the pericervical dentin thickness using 3D Cone Beam Computed Tomographic (CBCT) visualisation technique and fracture resistance of the maxillary anterior teeth under compressive load using universal testing machine. Materials and Methods: The in-vitro study was conducted in the Department of Conservative Dentistry and Endodontics at Karnavati School of Dentistry, Gandhinagar, Gujarat, India, from October 2020 to March 2021. Study was carried out on the 30 single rooted freshly extracted maxillary central incisors and were randomly divided into two groups of conventional and conservative access preparation groups (n=15). Group 1 was conventional group, samples were accessed using endo access bur #1. Group 2 was conservative group, samples were accessed using CK micro-endodontic bur under a dental operating microscope. Cleaning and shaping was done using 17% Ethylenediamine Tetraacetic Acid (EDTA) as lubricant and 4% Hyflex CM rotary file system. The CBCT scans were taken preoperatively, following access cavity preparation and postobturation to evaluate the amount of pericervical dentin loss in mesial, lingual, facial and distal surfaces of the teeth at the levels of 1 mm to 4 mm above and below Cementoenamel Junction (CEJ). The samples were then loaded to fracture in the Universal Testing Machine, and the data were analysed using Independent sample t-test using Statistical Package for Social Sciences (SPSS) software version 20.0. Results: In comparison to the group 2, group 1 led to an increase in substantial tooth structure loss in the pericervical region. Among all surfaces, pericervical dentin loss was more pronounced on the lingual surface in the group 1 than in the group 2 (p-value &lt;0.001). Higher fracture resistance was observed in group 2 (1136.75 N) compared to group 1 (687.22 N) under compressive load (p-value &lt;0.001). Conclusion: Incisal cavity design is a less invasive method of accessing maxillary central incisors that preserves pericervical dentin. Under compressive load, pericervical dentin conservation provided greater fracture resistance in the conservative group than in the conventional group.

Automated Orientation and Registration of Cone-Beam Computed Tomography Scans.

Automated clinical decision support systems rely on accurate analysis of three-dimensional (3D) medical and dental images to assist clinicians in diagnosis, treatment planning, intervention, and assessment of growth and treatment effects. However, analyzing longitudinal 3D images requires standardized orientation and registration, which can be laborious and error-prone tasks dependent on structures of reference for registration. This paper proposes two novel tools to automatically perform the orientation and registration of 3D Cone-Beam Computed Tomography (CBCT) scans with high accuracy (<3° and <2mm of angular and linear errors when compared to expert clinicians). These tools have undergone rigorous testing, and are currently being evaluated by clinicians who utilize the 3D Slicer open-source platform. Our work aims to reduce the sources of error in the 3D medical image analysis workflow by automating these operations. These methods combine conventional image processing approaches and Artificial Intelligence (AI) based models trained and tested on de-identified CBCT volumetric images. Our results showed robust performance for standardized and reproducible image orientation and registration that provide a more complete understanding of individual patient facial growth and response to orthopedic treatment in less than 5 min.

Morphological variation of nasopalatine canal: A cone-beam computed tomography study

Aim: 1) to assess the morphological variation of the nasopalatine canal (NPC) concerning age and gender. 2). to assess the correlation between the gender and morphology of the canal. 3). to assess the correlation between age and length of the canal.Materials and Methods: This is a retrospective, randomized observational study. The study comprised of 60 CBCT scans of maxilla showing NPC completely. The patients were in the age range of 15-75 years. Scan of 25 females and 35 males were included in the study. Patient below 15 years of age and NPC pathology or impacted teeth in same region were excluded in the study. The scans were obtained using ICAT17 19 machine and analyzed Vision software. Cone Beam 3D Imaging Machine operating at 120 kvp, 37.07 mAs with 0.25 mm voxel size, and a field of view of 16 × 6 cm maxilla.Results: Nasopalatine canal has 4 different morphological shapes. The most common shape was the cylindrical shape amongst both males and females. The least common shape was found to be hourglass shape with increasing age the length of NPC was found to decrease. The length of the canal was found to be longer in males when compared to femalesConclusion: This study highlights the importance of NPC morphology before or during surgical procedures involving the maxilla.

Value of Maxillary Sinus Morphology in Identification of Gender by Using Digital Radiography

Background: Human being recognition is significant for a variety of purposes, including for the humanitarian and sentimental needs for others, for relatives as well as for the court before rendering a decision. In forensic radiology, the radiographic tests and procedures that are relevant to the law or the courts are performed, interpreted, and then reported. Comparing radiography to three-dimensional (3D) cone beam computed tomography, radiography has the benefits of being more widely available, having a lower radiation dose, and having a lower cast. The systemic change in size or shape between individuals of varying sexes belonging to the same species is known as sexual dimorphism. Sexual dimorphism is reflected by different species' maxillary sinuses. The first paranasal sinus to develop in utero at the age of 10 weeks are the maxillary sinuses, which are two air-filled cavities found in the maxillary bone. They are the largest of the paranasal sinuses. Bones like the pelvis, skull, and femur are used in radiology to identify gender. Maxillary sinuses can be utilized for identification in mass tragedies like aero plane accidents, war, explosions, burnt, decomposing remains, and other calamities. In these situations, all the bones suffer severe damage, but the sinuses are left undamaged. Aim and objective: This research used digital radiography to identify gender based on the morphology of the maxillary sinus. Materials and Methods: From the radiographs (A.P view) of 128 subjects ( 64 males and 64 females), the morphometric characteristics of the maxillary sinus were assessed using microdicom software. Results: The right maxillary sinus average height and width in males was 28.15mm and 25.04mm whereas, in females it 22.39mm and 22.54mm respectively and was found statistically highly significant. Likewise, the left maxillary sinus average height and width in males was 28.91mm and 25.33mm and in females it was 22.39mm and 20.81mm respectively and was statistically highly significant. Conclusion: It was concluded from my study that the anteroposterior (AP) view of digital radiographs can be used to detect the gender based on the height and width of the maxillary sinuses. Keywords: Forensic radiography, maxillary sinus, sexual dimorphism, gender determination mass disaster.

Optimized workflow to minimise intra-fractional motion during stereotactic body radiotherapy of spinal metastases.

This study evaluated translational and rotational intra-fractional patient movement during spinal stereotactic body radiotherapy (SBRT) using 6D positioning based on 3D cone beam computerized tomography (CBCT) and stereoscopic kilovoltage imaging (ExacTrac). The aim was to determine whether additional intra-fractional image verification reduced intra-fractional motion without significantly prolonging treatment time, whilst maintaining acceptable imaging related dose. A retrospective analysis of 38 patients with 41 primary tumour volumes treated with SBRT between September 2018 and May 2021 was performed. Three different image-guided radiotherapy (IGRT) workflows were assessed. The translational and rotational positioning errors for the different imaging workflows, 3D translational vectors and estimates of imaging dose delivered for the different imaging workflows were evaluated. As the frequency of intra-fractional imaging increased from workflow 1 to 3, the mean intra-fraction 3D translational vector improved from 0.91mm (±0.52mm), to 0.64 (±0.34mm). 85%, 83% and 97% of images were within a tolerance of 1mm/1° for workflows 1, 2 and 3 respectively, based on post treatment CBCT images. The average treatment time for workflow 3 was 13min, as compared to 12min for workflows 1 and 2. The effective dose per treatment for IGRT workflows 1, 2 and 3 measured 0.6mSv, 0.95mSv and 1.8mSv respectively. The study demonstrated that the use of additional intra-fractional stereoscopic kilovoltage image-guidance during spinal SBRT, reduced the number of measurements deemed "out of tolerance" and treatment delivery could be optimized within a standard treatment timeslot without applying substantial additional radiation dose.

Evaluation of angulation between labial &amp; lingual surfaces of crown of anterior teeth &amp; 3D mapping lingual surface for development of concept of new preadjusted lingual bracket

Introduction: Lingual orthodontics grew slowly in North America in the 1980s as orthodontists grappled with the lingual technique, which needed distinct treatment planning and a different approach to biomechanics, as well as ergonomics and treatment efficacy difficulties. The early excitement of lingual orthodontic treatment faded with the discovery of "tooth-colored" labial brackets manufactured from single-crystal sapphire and later from ceramics, and much of the improvement of lingual orthodontics occurred outside the United States. Removable orthodontic aligners, rather than lingual braces, have become the treatment option for patients seeking invisible orthodontics with the introduction. The present work focuses of digital analysis and evaluation of angulation between labial &amp; lingual surface of crown of each anterior tooth and lingual curvature for the development of pre adjusted lingual bracket system. Material &amp; Methods: Sample consists of 100 dental cast (maxillary &amp; mandible) and 100 CBCT scans made at Santosh Dental College, Ghaziabad which were selected on the basis of Angle’s Class I molar relationship without any crowding, rotation, attrition, abrasion, erosion, abfraction &amp; anomaly on any tooth with the patient age group between 16 years to 20 years. CBCT scans were taken by KODAK 9500 Cone Beam 3D System (Carestream Health, Inc. &#x0D;

P120. Augmented reality navigation for percutaneous thoracolumbar pedicle screws: a prospective clinical study

<h3>BACKGROUND CONTEXT</h3> Conventional navigation systems depend on a separate imaging system and use of passive infra-red cameras with a bulky dynamic reference frame (DRF) attached to the spine and to the instruments for live tracking. This often leads to 1) issues with line of sight 2) need for an invasive procedure to attach the DRF 3) lowered accuracy due to inadvertent bumping of the DRF and when point of interest is further from the location of the DRF and 4) a need for repeated re-registrations that can affect the surgical workflow and impact the procedure time. These common issues that impede the adoption of navigation can be bypassed using an Augmented Reality Surgical Navigation system (ARSN), that combines the use of superior quality 3D intra-operative imaging and optical camera based Augmented Reality Navigation (ARN), noninvasive dynamic patient monitoring and on-shaft optical trackers on the Jamshidi needles to provide real time visual feedback of instrument location, without relying on fluoroscopy. <h3>PURPOSE</h3> To determine the accuracy of percutaneous pedicle screw placement when using ARSN. <h3>STUDY DESIGN/SETTING</h3> A single-arm, prospective multicenter clinical study. <h3>PATIENT SAMPLE</h3> A total of 211 pedicle screws were placed percutaneously in 39 patients between levels T2 and S1. The predominant indication was trauma (42%). However, patients with instability of the spine due to degenerative and neoplastic diseases were also included. <h3>OUTCOME MEASURES</h3> Accuracy of pedicle screw placement according to Gertzbein grading (Grade 0: no breach; Grade 1: 4mm breach) determined by three independent reviewers. The median time required to insert the pedicle screw in the right location when using the system was also noted. <h3>METHODS</h3> Navigation was performed in a hybrid OR including surgical table, motorized flat detector C-arm with intraoperative 2D/3D imaging capabilities, optical video cameras integrated in the detector for ARN, and patient motion tracking using skin markers. The C-arm rotated 180 degrees in 10 seconds during acquisition, creating a 3D Cone-Beam CT (CBCT) of the area of interest of 4-8 levels. A disposable Jamshidi needle with optical markers etched on the shaft was used to guide the needle to the desired location in the vertebral body using ARN. <h3>RESULTS</h3> Overall accuracy (Gertzbein 0-1) was 98.1% (95% CI 95.2-99.5). For thoracic screws (n=69), accuracy was 95.7%, for lumbar screws (n=126) 99.2%. Grade 0 screws (no breach) were 93% overall (86% in thoracic and 96% in lumbar levels). Four screws were graded as 2 (2-4 mm breach), with a medial positioning. Three of them were in the upper thoracic spine. None was associated with a neurological consequence. No screw was highly misplaced (> 4mm error). Six screws (2.7%) were intraoperatively revised. Median time per screw was 6 minutes and 25 sec (± 3.3 min). <h3>CONCLUSIONS</h3> Use of ARN leads to a high rate of accurate pedicle screw placement. The use of ARSN favorably compares to screw placement times reported in literature. <h3>FDA DEVICE/DRUG STATUS</h3> ClarifEye surgical navigation system (Philips Healthcare) (Approved for this indication)

First Clinical Experience with a Novel 3D C-Arm-Based System for Navigated Percutaneous Thoracolumbar Pedicle Screw Placement

Background and Objectives: Navigated pedicle screw placement is becoming increasingly popular, as it has been shown to reduce the rate of screw misplacement. We present our intraoperative workflow and initial experience in terms of safety, efficiency, and clinical feasibility with a novel system for a 3D C-arm cone beam computed-tomography-based navigation of thoracolumbar pedicle screws. Materials and Methods: The first 20 consecutive cases of C-arm cone beam computed-tomography-based percutaneous pedicle screw placement using a novel navigation system were included in this study. Procedural data including screw placement time and patient radiation dose were prospectively collected. Final pedicle screw accuracy was assessed using the Gertzbein–Robbins grading system. Results: In total, 156 screws were placed. The screw accuracy was 94.9%. All the pedicle breaches occurred on the lateral pedicle wall, and none caused clinical complications. On average, a time of 2:42 min was required to place a screw. The mean intraoperative patient radiation exposure was 7.46 mSv. Conclusions: In summary, the investigated combination of C-arm CBCT-based navigation proved to be easy to implement and highly reliable. It facilitates the accurate and efficient percutaneous placement of pedicle screws in the thoracolumbar spine. The careful use of intraoperative imaging maintains the intraoperative radiation exposure to the patient at a moderate level.

Frameless Co-Registration of Biplane 2D Digital Subtraction Angiography Whole Frames and 3D Rotational Angiography-Based Cone-Beam Computed Tomography Angiogram on Dedicated Software for Stereotactic Radiosurgery of Cranial Vascular Malformations.

Purpose: Given its high spatial resolution and vasculature selectivity, the cone-beam computed tomography (CT) angiography (CBCTA) image acquired by selective 3D rotational angiography (3DRA) is the most suitable 3D image for the target definition of stereotactic radiosurgery (SRS) for intracranial arteriovenous malformations (AVMs) and dural arteriovenous fistulas (DAVFs). Furthermore, the relatively low temporal resolution of 3DRA-based CBCTA can be complemented by the stereotactic co-registration of orthogonally paired 2D dynamic digital subtraction angiography (2D-DSA). The integration of 2D-DSA, which is usually limited to one or a few frames for each projection, into CBCTA and/or planning CT can be achieved only by catheter-directed angiography on the day of SRS via a dedicated image localizer under rigid frame fixation to the skull, which imposes substantial burdens on patients. This study aimed to demonstrate a novel, convenient, and significantly less invasive method for the frameless co-registration of biplane 2D-DSA whole frames and CBCTA on commercially available dedicated software, namely, Brainlab® Elements (Brainlab AG, Munich, Germany), and present its prerequisite for successful image fusion.Technical Report: Elements have afforded the following functionality: A 3D vasculature image is automatically extracted as a floating image from any 3D image series containing vascular details and then subsequently co-registered manually and automatically to a selected frame pair of 2D-DSA with a six-degree-of-freedom rigid registration. As a preclinical feasibility study, two anonymous image datasets from patients harboring cerebral AVM and transverse-sigmoid (TS) DAVF were used to verify the accuracy and practicality of Elements for the frameless co-registration of 2D/3D vascular images, particularly on the assumption of clinical workflow for the target delineation of SRS planning. The use of ordinary unsubtracted CBCTA resulted in the insufficient extraction of abutting vessels or vessels that are in close proximity to bony structures, particularly in the case of TS-DAVF, where the fistulous pouch and the affected venous sinuses were adjacent to the cranial bone. By contrast, the amount and selectivity of vasculatures and the accuracy of subsequent image fusion were significantly improved from the subtracted CBCTA. The integration of CBCTA into dynamic 2D-DSA allowed the simultaneous review of both image information by sharing any concerning point and 2D or 3D structures under a common 3D coordinate.Conclusions: Elements enable the clinically useful frameless co-registration of biplane 2D-DSA whole frames into CBCTA, for which the routine acquisition of both subtracted and unsubtracted CBCTA axial images for ordinary diagnostic purposes is an indispensable prerequisite for successful image fusion and further widespread application. This frameless integration of the 2D/3D angiogram would dramatically enhance both the frame-based and frameless SRS workflow and circumstances by allowing users to forward SRS planning well in advance before SRS, along with the omission of invasive angiography on the day of SRS, and would broaden the implementation of frameless SRS. Furthermore, the comprehensive alternating interactive review of the 2D/3D integrated angiogram leads to a more in-depth quasi-4D understanding of the affected angioarchitectures compared with the separate viewing of each image.