Evaluation of Maxillary Sinus Septa Using Cone Beam Computed Tomography (CBCT): A Retrospective Study.

BACKGROUND: Maxillary sinus septa, which are bony structures dividing the sinus cavity, can pose challenges during sinus lift or implant surgeries by potentially causing perforation of the Schneiderian membrane. This study aimed to estimate the prevalence, height, location, orientation, and risk of perforation of the maxillary sinus septa using cone beam computed tomography (CBCT). MATERIALS AND METHODS: This retrospective, cross-sectional study utilized CBCT (NewTom CBCT machine, of which the scan parameters were 90 KvP, 8 mAs, and 14 s exposure with a field of view (FOV) of 8×8 cm and a 0.2 mm3 voxel size) images of 300 maxillary sinuses from patients aged >18 years, obtained from Swami Devi Dyal Hospital and Dental College in Panchkula, India. Scans were analyzed for the presence, height, location, orientation, and risk of septal perforation. The data were categorized based on age, sex, and dentition status. Statistical analyses were performed to assess the prevalence, configuration, and risk factors. RESULTS: The prevalence of maxillary sinus septa was 21.33%, with the majority showing a single septum (90.63%). Septa were predominantly found in the middle region (48.44%), with bucco-palatal orientation (93.75%) being more common than anteroposterior. The mean septa height was 6.16 mm. The perforation was classified as moderate (48.4%), low (46.8%), or high (4.6%). Class III septa were associated with the highest risk of perforation. CONCLUSION: This study highlights a significant prevalence of maxillary sinus septa with variations in height, orientation, and location. The risk of perforation varies with the septa configuration and orientation. CBCT is essential for identifying these anatomical features to minimize surgical complications and to guide preoperative planning.

Weekly Image Guidance in Patients With Cervical Cancer Treated With Intensity-Modulated Radiation Therapy: Results of a Large Cohort Study.

BACKGROUND: Image guidance is recommended for patients undergoing intensity-modulated radiation therapy (IMRT) for cervical cancer. In this study, we evaluated the feasibility of a weekly image guidance pattern and analyzed the long-term outcomes in a large cohort of patients. METHODS: The study enrolled patients with Stage IB-IVA cervical cancer who received definitive radiotherapy or concurrent chemoradiotherapy. IMRT was delivered at a dose of 50.4 Gy in 28 fractions, with weekly cone-beam computed tomography (CBCT). Physicians advised patients on rectum and bladder preparation to help them prepare on nonimaging guidance days. When significant tumor regression was observed, a second computed tomography simulation and replanning were performed. RESULTS: The median follow-up periods were 63.4 months. The incidence rates of loco-regional and distant failure were 9.9% and 13.6%. The 5-year overall survival (OS), disease-free survival (DFS), loco-regional relapse-free survival (LRFS), and distant metastasis-free survival (DMFS) rates were 80.1%, 72.9%, 78.3%, and 74.8%, respectively. For patients with different stages, the 5-year OS, DFS, LRFS, and DMFS rates were statistically significant. For patients with and without positive regional lymph nodes, the 5-year OS, DFS, LRFS, and DMFS rates were 64.5% and 86.0%, 56.8% and 78.8%, 62.7% and 84.3%, and 58.8% and 81.0%, respectively. Multivariate analysis showed that age, histology, tumor size, cancer stage, pretreatment squamous cell carcinoma antigen level, and para-aortic metastatic lymph nodes were independent prognostic factors of OS. Fifty-six (4.0%) patients experienced late Grade 3/4 chronic toxicities. CONCLUSIONS: IMRT with weekly CBCT is an acceptable image guidance strategy in countries with limited medical resources.

Metric learning guided sinogram denoising for cone beam CT enhancement.

BACKGROUND: Cone beam computed tomography (CBCT) is a widely available modality, but its clinical utility has been limited by low detail conspicuity and quantitative accuracy. Convenient post-reconstruction denoising is subject to back projected patterned residual, but joint denoise-reconstruction is typically computationally expensive and complex. PURPOSE: In this study, we develop and evaluate a novel Metric-learning guided wavelet transform reconstruction (MEGATRON) approach to enhance image domain quality with projection-domain processing. METHODS: Projection domain based processing has the benefit of being simple, efficient, and compatible with various reconstruction toolkit and vendor platforms. However, they also typically show inferior performance in the final reconstructed image, because the denoising goals in projection and image domains do not necessarily align. Motivated by these observations, this work aims to translate the demand for quality enhancement from the quantitative image domain to the more easily operable projection domain. Specifically, the proposed paradigm consists of a metric learning module and a denoising network module. Via metric learning, enhancement objectives on the wavelet encoded sinogram domain data are defined to reflect post-reconstruction image discrepancy. The denoising network maps measured cone-beam projection to its enhanced version, driven by the learnt objective. In doing so, the denoiser operates in the convenient sinogram to sinogram fashion but reflects improvement in reconstructed image as the final goal. Implementation-wise, metric learning was formalized as optimizing the weighted fitting of wavelet subbands, and a res-Unet, which is a Unet structure with residual blocks, was used for denoising. To access quantitative reference, cone-beam projections were simulated using the X-ray based Cancer Imaging Simulation Toolkit (XCIST). In both learning modules, a data set of 123 human thoraxes, which was from Open-Source Imaging Consortium (OSIC) Pulmonary Fibrosis Progression challenge, was used. Reconstructed CBCT thoracic images were compared against ground truth FB and performance was assessed in root mean square error (RMSE), peak signal-to-noise ratio (PSNR), and structural similarity index (SSIM). RESULTS: MEGATRON achieved RMSE in HU value, PSNR, and SSIM were 30.97 ± 4.25, 37.45 ± 1.78, and 93.23 ± 1.62, respectively. These values are on par with reported results from sophisticated physics-driven CBCT enhancement, demonstrating promise and utility of the proposed MEGATRON method. CONCLUSION: We have demonstrated that incorporating the proposed metric learning into sinogram denoising introduces awareness of reconstruction goal and improves final quantitative performance. The proposed approach is compatible with a wide range of denoiser network structures and reconstruction modules, to suit customized need or further improve performance.

Supervised deep learning-based synthetic computed tomography from kilovoltage cone-beam computed tomography images for adaptive radiation therapy in head and neck cancer.

PURPOSE: To generate and investigate a supervised deep learning algorithm for creating synthetic computed tomography (sCT) images from kilovoltage cone-beam computed tomography (kV-CBCT) images for adaptive radiation therapy (ART) in head and neck cancer (HNC). MATERIALS AND METHODS: This study generated the supervised U-Net deep learning model using 3,491 image pairs from planning computed tomography (pCT) and kV-CBCT datasets obtained from 40 HNC patients. The dataset was split into 80% for training and 20% for testing. The evaluation of the sCT images compared to pCT images focused on three aspects: Hounsfield units accuracy, assessed using mean absolute error (MAE) and root mean square error (RMSE); image quality, evaluated using the peak signal-to-noise ratio (PSNR) and structural similarity index (SSIM) between sCT and pCT images; and dosimetric accuracy, encompassing 3D gamma passing rates for dose distribution and percentage dose difference. RESULTS: MAE, RMSE, PSNR, and SSIM showed improvements from their initial values of 53.15 ± 40.09, 153.99 ± 79.78, 47.91 ± 4.98 dB, and 0.97 ± 0.02 to 41.47 ± 30.59, 130.39 ± 78.06, 49.93 ± 6.00 dB, and 0.98 ± 0.02, respectively. Regarding dose evaluation, 3D gamma passing rates for dose distribution within sCT images under 2%/2 mm, 3%/2 mm, and 3%/3 mm criteria, yielded passing rates of 92.1% ± 3.8%, 93.8% ± 3.0%, and 96.9% ± 2.0%, respectively. The sCT images exhibited minor variations in the percentage dose distribution of the investigated target and structure volumes. However, it is worth noting that the sCT images exhibited anatomical variations when compared to the pCT images. CONCLUSION: These findings highlight the potential of the supervised U-Net deep learningmodel in generating kV-CBCT-based sCT images for ART in patients with HNC.

Accuracy of Different Dental Age Estimation Methods Using Cone Beam Computed Tomography: A Comparative Study.

Background: Age assessment is useful in various fields of dentistry due to its ability to influence the planning of dental treatments. Dental age estimation methods are specifically based on age-related variables observed in two-dimensional (2D) radiographs in the dentition in terms of the time of emergence and are considered reliable in determining the chronological age; however, the inevitable problems of orientation errors found in 2D can be eliminated using cone beam computed tomography (CBCT). Objective: This study aimed to compare the accuracy of different radiological dental age estimation methods using CBCT in relation to the chronological age of children. Materials and methods: A total of 100 CBCT images of patients in the age-group of 8-15 years requiring orthodontic treatment were obtained from December 2019 to August 2022. The exact chronological age was determined through valid proof, that is, aadhar card or birth certificate. The dental age of the children was assessed using all four methods-Nolla's method (NM), Demirjian method (DM), Schour and Massler (S&M), and Cameriere method (CM). Results: The results found that NM underestimated the mean age by 0.24 years, while DM overestimated the mean age by 0.82 years. Both showed statistically significant differences based on the standard deviation (SD) (p < 0.05). S&M and CM also overestimated the mean age by 1.16 years and 2.75 years respectively, but with statistically nonsignificant differences (p > 0.05). Conclusion: Among the four tested radiographic methods, the best accuracy was found with NM, which tended to underestimate but was closest to the chronological age. CBCT provided better age estimation values without image distortion. How to cite this article: Tyagi A, Srivastava N, Rana V, et al. Accuracy of Different Dental Age Estimation Methods Using Cone Beam Computed Tomography: A Comparative Study. Int J Clin Pediatr Dent 2024;17(5):558-564.

Comparison of three approaches for treating the bony access window in lateral sinus floor elevation: a retrospective analysis.

The aim of this study was to retrospectively determine the effects of applying different treatment methods to the bony access window on the healing outcomes in lateral sinus floor elevation (SFE). Lateral SFE with implant placement was performed in 131 sinuses of 105 patients. The following three treatment methods were applied to the bony access window: application of a collagen barrier (group CB), repositioning the bone fragment (group RW) and untreated (group UT). Radiographic healing in the window area, augmented bone height changes and marginal bone level changes were examined. Mixed logistic and mixed linear models were analyzed. Over 4.3 ± 1.4 years of follow-up, the implant survival rate was 100% in groups CB and UT, and 96.9% in group RW. The treatment applied to the window did not significantly influence the radiographic healing in the window area, augmented bone height changes or marginal bone level changes (p > 0.05). The healed window areas had generally flat morphologies and were fully corticalized. The mean changes in the augmented bone were less than 1.5 mm in all groups. Marginal bone level changes were minimal. In conclusion, Healing outcomes were not different among three different methods to treat the bony access window in lateral SFE.

Fractal Dimension and Lacunarity Analysis in the Dentulous and Edentulous Mandibular Posterior Region Using Cone-beam Computed Tomography: A Cross-sectional Retrospective Study.

AIMS: This cross-sectional retrospective study was conducted to assess the differences in the microarchitecture of the trabecular bone of the posterior mandibular region at dentulous and edentulous sites with the help of fractal dimension (FD) and lacunarity using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: Ninety CBCT scans were analyzed for the purpose of the present study. Inclusion criteria included subjects with unilaterally missing mandibular molars or premolars and an with intact contralateral opposing tooth. The coronal view of the dentulous and edentulous sites was used, and the region of interest (ROI) was selected 2.6 mm below the apex of the tooth present. These images were then transferred to ImageJ Software, and fractal analysis was done using the box-counting method of the FracLac plug-in. A paired samples t-test was performed to compare the means of FD and lacunarity, and a Kendall correlation was performed to check correlations. A p-value less than 0.05 was considered to indicate statistical significance. RESULTS: Statistical analysis revealed that the mean FD of the edentulous side was significantly greater than that of the dentulous side (p-value = 0.011). Additionally, the mean lacunarity of the edentulous side was marginally significantly greater than that of the dentulous side (p-value = 0.089). A significant negative correlation was detected between the FD and lacunarity of the edentulous region (p-value = 0.017), and a marginally significant negative correlation was detected between edentulous lacunarity and dentulous lacunarity (p-value = 0.081). CONCLUSION: The differences in occlusal forces exerted in dentulous and edentulous regions can lead to a change in the trabecular pattern of the bone in these regions. This change in the microarchitecture of bones can be detected by FD and lacunarity, which can further help us assess changes pre- and post-implant. CLINICAL SIGNIFICANCE: The advanced technology, the assessment of microarchitecture of the bone has been made easy, using FD and lacunarity, as done in the present study. This analysis can further aid us in both pre- and post-implant analysis to prevent failure of the implant. How to cite this article: Bhoraskar M, Denny C, Srikant N, et al. Fractal Dimension and Lacunarity Analysis in the Dentulous and Edentulous Mandibular Posterior Region Using Cone-beam Computed Tomography: A Cross-sectional Retrospective Study. J Contemp Dent Pract 2024;25(6):581-587.

Efficacy of Mastoid Morphometry in Sex Determination Using Cone-beam Computed Tomography: A Retrospective Analysis in Dakshina Kannada Population.

AIM: To evaluate the morphology of the mastoid process and its role in sex determination with the help of cone-beam computed tomography (CBCT). MATERIALS AND METHODS: A retrospective study was conducted on 200 adults who were subjected to full FOV CBCT scans (100 males and 100 females). Eight parameters of the mastoid process were assessed for sex determination. The study measured eight parameters of the mastoid process, including mastoid length (ML), mastoid width, mastoid height (MH), intermastoidale distance (IMD), intermastoidale lateral surface distance (IMLSD), mastoid medial convergence angle, mastoid size (MS), and mastoid surface area (MSA). Data were recorded and statistically analyzed. RESULTS: Statistics revealed a significant value for MH (p < 0.001), IMD (p < 0.001), IMLSD (p < 0.001), MSA (p < 0.001), MS (p < 0.001), and ML (p = 0.032). A highly significant value was noted for MH (p < 0.001), IMD (p < 0.001), IMLSD (p < 0.001), MSA (p < 0.001), MS (p < 0.001), followed by ML, all of which were found to be greater in males. Out of the eight parameters, IMD was found to be the best sex determinant among all the eight parameters, with an accuracy of 70%. The study showed a significant difference between the mastoid process morphometric measurements for males and females. CONCLUSION: It can be concluded from the present study that IMD can be used as a good index for sex determination. The combined parameters that were found to be the most accurate were right MH, left ML, and IMLSD, with an accuracy of 75%. CLINICAL SIGNIFICANCE: The three-dimensional imaging techniques can contribute significantly towards disaster victim identification and sex determination in the fields of forensic odontology and anthropology. For the recognition of victims, sex determination becomes one of the most difficult parameters to assess. In such events, the mastoid process can become an important anatomical landmark for the estimation of sex. This is due to the condensed nature of the petrous bone and its protected position in the skull. How to cite this article: Ahmed J, Saha A, Muralidharan A, et al. Efficacy of Mastoid Morphometry in Sex Determination Using Cone-beam Computed Tomography: A Retrospective Analysis in Dakshina Kannada Population. J Contemp Dent Pract 2024;25(5):453-458.

Finite element analysis of non-ultraviolet and ultraviolet-irradiated titanium implants.

AIM: The purpose of this study is to calculate von Mises stresses, von Mises strains, deformation, principal stresses and principal elastic strains of non-UV and UV-irradiated hybrid SLA (sandblasted, large-grit, acid-etched)-coated titanium implants. MATERIALS AND METHODS: A cross-sectional analytical study was conducted at the Institute of Dentistry, CMH Lahore Medical College. Cone beam computed tomography (CBCT) data of One Hundred and Thirty Eight Dio Hybrid sandblasted and acid-etched implants of identical dimensions (10 mm in length and 4.5 mm in diameter) were allocated in the three groups. Control group A samples were not given UV irradiation, while groups B and C were given UVA (382 nm, 25 mWcm-2) and UVC (260 nm, 15 mWcm-2) irradiation, respectively. The CBCT data were analyzed using FEA (ANSYS software). CBCT images were taken before functional loading (8th week) and after functional loading (26th week). A 3-way ANOVA test was employed to see the difference between the three groups. Tukey test was utilized for multiple comparisons. p ≤ 0.05 was considered significant. RESULTS: The control group exhibited the highest average values for maximum von Mises stress, von Mises strain, deformation, principal stress, and principal elastic strain in both the maxilla and mandible compared to the UV-irradiated groups. Additionally, these measures consistently displayed higher averages in the maxilla across all groups compared to the mandible. Particularly, the UVC-irradiated group demonstrated the lowest von Mises stresses around the implants compared to the UVA group. CONCLUSION: Insignificant differences were observed between UVA- and UVC-irradiated implants in terms of principal stress, deformation, von Mises strain, and principal elastic strain. The only notable distinction was in von Mises stress, where the UVC-irradiated group exhibited lower von Mises stress around SLA-coated titanium implants.

Procedural times with robotic-assisted bronchoscopy: a high volume single-center study.

BACKGROUND: Incidental and screen-detected pulmonary nodules are common. The increasing capabilities of advanced diagnostic bronchoscopy will increase bronchoscopists' procedural volume necessitating optimization of procedural scheduling and workflow. OBJECTIVES: The objectives of this study were to determine total time in the procedure room, total bronchoscopy procedure time, and robotic-assisted bronchoscopy procedure time longitudinally and per specific procedure performed. DESIGN: A single-center observational study of all consecutive patients undergoing shape-sensing robotic-assisted bronchoscopy (RAB) biopsy procedures for the evaluation of pulmonary lesions with variable probability for malignancy. METHODS: Chart review to collect patient demographics, lesion characteristics, and procedural specifics. Descriptive and comparative statistics are reported. RESULTS: Actual bronchoscopy procedure time may decrease with increased institutional experience over time, however, there is limited ability to reduce non-bronchoscopy related time within the procedure room. The use of cone beam computed tomography (CBCT), rapid on-site evaluation (ROSE), and performance of staging endobronchial ultrasound transbronchial needle aspiration (EBUS-TBNA) in a single procedure are each associated with additional time requirements. CONCLUSION: Institutional procedural block times should adapt to the nature of advanced diagnostic bronchoscopy procedures to allow for the accommodation of new modalities such as RAB combined with other technologies including radial endobronchial ultrasound, CBCT, ROSE, and staging linear EBUS. Identifying institutional median procedural times may assist in scheduling and ideal block time utilization.

Times necessary to perform robotic assisted bronchoscopy biopsy procedures at a single hospitalBackground: Lung lesions and nodules are commonly seen on computed tomography (CT) scans. With advances in technology, more of these lesions are being biopsied with robotic assisted bronchoscopy (RAB) procedures, leading to increased demand. Health care providers who perform these procedures have finite available time in which they must accommodate all their procedures. Understanding procedure times is necessary to fully utilize schedules. Methods and aims overview: We describe our experience of 5 pulmonologists performing 700 robotic assisted bronchoscopies at a single hospital. Our aim is to describe the time needed for the robotic bronchoscopies over time and with specific procedures. Results and conclusion: We find that as more robotic assisted bronchoscopies are performed, the overall procedure time may decrease. Using cone beam computed tomography during the procedure, having on- site pathology review of biopsies, and obtaining biopsies of lymph nodes may lengthen the procedure time. The time spent preparing the patient for the procedure excluding the bronchoscopy remained stable. Understanding the time necessary based on what is performed during the procedure will allow it to be scheduled for the appropriate amount of time. As a result, procedure days can be fully optimized, minimizing scheduling impacts on patients and health care workers.

Pulp calcification identification on cone beam computed tomography: an artificial intelligence pilot study.

BACKGROUND: This study aims to verify the effectiveness of a deep neural network (DNN) in automatically identifying pulp calcification on cone beam computed tomography (CBCT) images. METHODS: This study retrospectively analysed 150 CBCT images. Pulp calcification was identified and manually annotated by three endodontists with 10 years of experience. A DNN model based on the U-Net architecture was constructed to identify pulp calcification, and ten rounds of fourfold cross-validation were conducted. The model performance was evaluated using sensitivity, specificity, accuracy, and the area under the receiver operating characteristic curve (AUC). RESULTS: The model achieved a sensitivity of 75.91 ± 2.84% in automatically identifying pulp calcification, with a specificity of 68.88 ± 2.35%, an accuracy of 72.78 ± 2.13%, and an AUC of 73.68 ± 3.09%. According to the ranking for diagnostic tests, the proposed method achieved a "good" grade for sensitivity, accuracy, and AUC and a "fair" grade for specificity. CONCLUSIONS: The results indicate that the proposed method shows promise for identifying pulp calcification on CBCT images. Future research aims to expand the dataset and refine the model, thereby enhancing its clinical applicability. The integration of artificial intelligence into diagnostic and treatment systems is anticipated to increase the efficiency of diagnosing pulp calcification and assist dentists in assessing the difficulty of root canal treatment cases preoperatively. CLINICAL REGISTRATION: Registration was performed on the Chinese Clinical Trial Registry ( https://www.chictr.org.cn/ ) (Registration number: ChiCTR2300077078, 27/10/2023) and National Medical Research Registry Information System ( https://www.medicalresearch.org.cn/ , 30/10/2023) (Number: MR-44-23-039664).

State of the art: peripheral diagnostic bronchoscopy.

Lung cancer is the leading cause of cancer related death worldwide and in the United States according to the World Health Organization and National Cancer Institute. Improvements in the diagnosis and treatment of lung cancer are of the utmost importance. A prompt diagnosis is a crucial factor to improve outcomes in the treatment of lung cancer. Although the implementation of lung cancer screening guidelines and the overall steady growth in the use of computed tomography have improved the likelihood of detecting lung cancer at an earlier stage, the diagnosis of peripheral pulmonary lesions (PPLs) has remained a challenge. The bronchoscopic techniques for PPL sampling have historically offered modest diagnostic yields at best in comparison to computed tomography guided transthoracic needle aspiration (TTNA). Fortunately, recent advances in technology have ushered in a new era of diagnostic peripheral bronchoscopy. In this review, we discuss the introduction of advanced intraprocedural imaging included digital tomosynthesis (DT), augmented fluoroscopy (AF), and cone beam computed tomography. We discuss robotic assisted bronchoscopy with a review of the currently available platforms, and we discuss the implementation of novel biopsy tools. These technologic advances in the bronchoscopic approach to PPLs offer greater diagnostic certainty and pave the way toward peripheral therapeutics in bronchoscopy.

Cone-Beam Computed Tomography-Guided Adaptive Radiotherapy: A Case Report on Dynamic Tumor Response in Lung Adenocarcinoma.

Cone-beam computed tomography (CBCT) is an essential tool in radiotherapy, enhancing patient positioning accuracy and enabling precise treatment delivery by monitoring anatomical changes throughout the treatment process. This case report highlights the significant role of CBCT in managing a patient with lung adenocarcinoma treated with concurrent chemoradiation. The lung mass and lower paratracheal lymph nodes were irradiated with 60 Gy in 30 fractions. During the course of treatment, CBCT allowed us to observe substantial tumor shrinkage, prompting a treatment replanning to ensure optimal targeting of the tumor while minimizing radiation exposure to healthy tissues. This adaptive approach resulted in excellent treatment outcomes with no complications, demonstrating the efficacy of CBCT in modern radiotherapy.

Correlations of temporomandibular joint morphology and position using cone-beam computed tomography and dynamic functional analysis in orthodontic patients: A cross-sectional study.

Objective: To correlate temporomandibular joint (TMJ) morphology and position with cone-beam computed tomography (CBCT) images, Joint Vibration Analysis (JVA), and Jaw Tracker (JT) to develop a radiation-free, dynamic method for screening and monitoring the TMJ in orthodontic patients. Methods: A total of 236 orthodontic patients without symptoms of TMJ disorders who had undergone CBCT were selected for the JVA and JT tests in this cross-sectional study. TMJ position and morphology were measured using a three-dimensional analysis software. JT measurements involved six opening-closing cycles, and JVA measurements were performed using a metronome to guide the mouth opening-closing movements of the patients. The correlations among the three measuring devices were evaluated. Results: Abnormalities in condylar surface morphology affected the mandibular range of motion. The cut-off value results show that when various measurement groups are within a certain range, abnormalities may be observed in morphology (area under the curve, 0.81; P < 0.001). A 300/< 300 Hz ratio ≥ 0.09 suggested abnormal morphology (P < 0.05). Correlations were observed among the maximum opening velocity, maximum vertical opening position, and joint spaces in the JT measurements. Correlations were also observed between the > 300/< 300 Hz ratio, median frequency, total integral, integral < 300 Hz, and peak frequency with joint spaces in the JVA measurements. Conclusions: JT and JVA may serve as rapid, non-invasive, and radiation-free dynamic diagnostic tools for monitoring and screening TMJ abnormalities before and during orthodontic treatment.

Efficacy of Online Adaptive Radiotherapy Using Surface Guidance in Treatment of Tracheal Adenoid Cystic Carcinoma.

Primary tracheal tumors are rare, with adenoid cystic carcinoma (ACC) of the trachea being the second most common malignancy of the trachea. Radical surgical resection is found to have better survival outcomes in tracheal ACC. However, with higher submucosal spread rates in tracheal ACC and the inability to achieve clear margins, complete resection is not usually achievable. In these cases, the use of a 60-70 Gy radiation dose is deemed to be sufficient for definitive treatment with or without concurrent chemotherapy. We report a case of an unresectable ACC treated with online daily adaptive cone beam computed tomography (CBCT) radiotherapy on Ethos™ (Varian Medical Systems, Palo Alto, CA). She was planned to receive 59.4 Gy in 33 fractions in two phases. For daily treatment delivery, the patient was set up on the couch using the surface-guided radiotherapy (SGRT) system of AlignRT™ (Vision RT Ltd., London, UK) and translated to the treatment isocenter. A CBCT scan was acquired, followed by rigid registration with the planning scan and PET CT. Organs at risk (OAR) and primary targets were auto-generated by the AI in a two-step process, reviewed, and edited by the radiation oncologist. Adapted and scheduled plans were compared regarding planning target volume (PTV) coverage and dose to OAR. Better PTV coverage was seen in 26 of 33 fractions with the adapted plan. On the days with lesser coverage, adapted plans demonstrated improvement in the hotspot reduction and reduction in hard dose constraints of the esophagus and lungs. Hence, adapted plans were selected for all treatment days. Our results highlight the superior target coverage and improved OAR-sparing plans in daily online adaptive radiotherapy (o-ART) compared to image-guided radiotherapy (IGRT) plans. The system's ability to adapt to daily anatomical changes, improved target coverage, and better sparing of OARs make it an encouraging option for malignancies requiring motion management.

Variations of the Lingula and Mandibular Ramus in the Context of Sagittal Split Ramus Osteotomy: A Cone Beam Computed Tomography Study Supporting an Ethnic-Centric Approach to Orthognathic Surgery.

OBJECTIVES: To investigate the ethnic variations concerning the lingula and ramus of the mandible, with particular emphasis on sagittal split ramus osteotomy (SSRO) in orthognathic surgery. MATERIALS AND METHODS: This study examined Cone beam computed tomography (CBCT) scans from the Kenyan and Malay populations. Lingula morphology was classified into four categories. Morphometric measurements included lingula size, height above the occlusal plane, distance to the second mandibular molar, and distance from its apex to all four mandible borders. Regarding the ramus of the mandible, the thickness of each cortical plate, trabecular bone, and overall thickness were determined at two points. Furthermore, points of fusion of cortical plates were determined in both the vertical and horizontal planes. RESULTS: Among Kenyans, the triangular shape was most common (46.5%, n = 80 sides), while truncated was most common among Malays (34.4%, n = 57 sides). The overall mean size of lingula differed significantly between Kenyan (7.37 ± 2.19 mm) and Malay (4.14 ± 2.50 mm) populations (p<0.001). The lingula was more located postero-superiorly in Kenyans compared to Malays (p < 0.001). The mean distance from the distal aspect of the second mandibular molar to the lingula was 38.37 ± 4.98 mm among Kenyans, in contrast to 31.95 ± 0.03 mm among Malays (p < 0.001). The Malays exhibited a thicker mandible with a larger trabecular distance (5.99 ± 1.41 mm and 3.41 ± 1.29 mm, respectively) than Kenyans (5.28 ± 1.39 mm and 1.98 ± 0.98 mm, respectively) (p < 0.001). The points of fusion of the cortical plates differed significantly between Kenyans and Malays. CONCLUSION: This study focuses on two ethnic groups, Kenyans and Malays, and brings to light the ethnic-based differences in the position of the lingula and the dimensions of the mandibular ramus, both of which are essential considerations in orthognathic surgery. Preoperative consideration of such variations is warranted, potentially mitigating iatrogenic injuries and enhancing successful patient outcomes.

The Impact of Minimum Invasive Access Cavity Design on the Quality of Instrumentation of Root Canals of Maxillary Molars Using Cone-Beam Computed Tomography: An in Vitro Study.

Aim Minimally invasive dentistry has been facilitated by advances in instruments and restorative materials. This study aims to compare the change in the shaping ability of the RECIPROC blue rotary system in both traditional and conservative access cavities, using cone beam computed tomography (CBCT). Material and methods Sixty root canals of 20 artificial maxillary molars were assigned into two groups (n=30 root canals) according to the access cavity design used: Group I: traditional access cavity (TAC) and Group II: conservative access cavity (CAC). CBCT scans of samples were made before and after root canal preparation using the RECIPROC blue rotary system. The shaping parameters are evaluated in root canal transportation and the centering ability. Three CBCT sections per tooth were analyzed at 3, 6, and 9 mm from the apex to assess the canal transportation and centering ability at three levels, apical, middle, and coronal thirds. Data were analyzed using the GraphPad Prism (GraphPad Software, San Diego, CA). Results The results of this study showed a significant difference in transportation within the coronal and middle thirds. However, in apical thirds, there were no significant differences. Both groups observed a significant difference in the centering ability in the coronal third. Conclusion Within the limitations of this study, CAC can be recommended with caution as an alternative access to TAC.

The impact of CBCT on outcomes associated with endodontic access cavity preparation: a controlled human analogue study using 3D printed first maxillary molars.

OBJECTIVES: To identify if supplemental preoperative CBCT imaging could improve outcomes related to endodontic access cavity preparation, using 3D-printed maxillary first molars (M1Ms) in a rigorously simulated, controlled human analogue study. METHODS: 18 operators with three experience-levels took part in two simulated clinical sessions, one with and one without the availability of CBCT imaging, in a randomised order and with an intervening 8-week washout period. Operators attempted location of all four root canals in each of three custom-made M1Ms (two non-complex and one complex mesiobuccal canal anatomy). Primary outcome was tooth volume removed. Secondary outcomes were linear cavity dimensions, canals located, and procedural time. Operator confidence and 'helpfulness' of available imaging were recorded. Statistical analysis of data included: paired t-tests, Fishers Exact test, linear mixed effect modelling and Mann-Whitney U test, with an alpha level of .05 for all. RESULTS: When supplemental preoperative CBCT was available, there were significant reductions in volume of the access cavity and procedural times, with significantly increased mesiobuccal-2 (MB2) canal location, but only for teeth with non-complex anatomies and for more experienced operators. Linear mixed-effect modelling identified image type and operator experience as significant predictors of tooth volume removed and procedural time. There was significantly lower confidence in canal location and perceived 'helpfulness" (all experience groups) when conventional imaging only was used compared with when CBCT was available. CONCLUSIONS: Supplemental preoperative CBCT had several beneficial impacts on access cavity preparation, although this only applied to teeth with non-complex anatomy and for more experienced operators.

Investigation of nasal cavity alterations in individuals with neurofibromatosis type 1 using CBCT.

OBJECTIVES: This study aimed to investigate nasal septum deviation (NSD), nasal bone length (NBL), and the morphology of the middle nasal conchae (MNC) and inferior nasal conchae (INC), as well as their correlations. MATERIALS AND METHODS: The sample included 56 cone-beam computed tomography scans divided into two groups: a study group (SG; individuals with NF1; n = 28) and a control group (CG; individuals without NF1; n = 28). NSD, NBL, MNC, and INC classifications were assessed. MNC images were classified as normal, bullous, paradoxical, secondary, and accessory. INC images were classified as normal, lamellar, compact, combined, and bullous. Intra- and interobserver reliability were evaluated. RESULTS: SG had a mean NSD of 11.6° (±4.5°) compared with 9.6° (±3.2°) for the CG, showing moderate deviations with no significant difference between groups. SG had a mean NBL of 22.4 mm (±3.4 mm) compared with 22.1 mm (±3.2 mm) for the CG, with a statistically significant difference. Both groups exhibited normal, bullosa, and accessory MNC classifications. SG INC were normal, lamellar, and combined, whereas CG INC were normal and lamellar. There was a weak correlation between NSD and NBL across groups. CONCLUSION: Individuals with NF1 showed longer NBL. The weak correlation between NSD and NBL suggested multifactorial influences on these variations. These findings advance our understanding of craniofacial development in NF1 and highlight the need for further research into nasal cavity involvement in this complex genetic disorder.

Comparative Analysis of Two Different Techniques for Ridge Preservation Following Tooth Extraction: A Clinical and Radiographic Study.

Background: Ridge preservation following tooth extraction is essential for maintaining the alveolar bone structure and facilitating successful dental implant placement. Various techniques have been proposed for this purpose, but there remains a need for comparative analysis to determine their efficacy. Materials and Methods: This clinical and radiographic study compared two different techniques for ridge preservation: Technique A and Technique B. Fifty patients requiring tooth extraction were randomly assigned to either Technique A or Technique B group. Clinical parameters including pain, swelling, and soft tissue healing were evaluated postoperatively. Radiographic assessments were conducted to measure the dimensional changes in the alveolar ridge at baseline and after 3 months using cone-beam computed tomography (CBCT). Results: In the Technique A group, postoperative pain scores averaged 2.3 (±0.5) on a visual analog scale (VAS), while in the Technique B group, the average pain score was 2.5 (±0.6). The swelling was minimal in both groups with no significant difference. Soft tissue healing was satisfactory in both groups. Radiographically, the mean vertical bone loss was 1.2 mm (±0.3) in the Technique A group and 0.9 mm (±0.4) in the Technique B group, with a statistically significant difference (P < 0.05). Conclusion: Both Technique A and Technique B demonstrated favorable outcomes in terms of postoperative discomfort and soft tissue healing. However, Technique B showed superior preservation of vertical ridge dimensions compared to Technique A. Therefore, Technique B may be considered more effective for ridge preservation following tooth extraction.