Cone Beam Computed Tomography Scans Research Articles

A cross-temporal multimodal fusion system based on deep learning for orthodontic monitoring

IntroductionIn the treatment of malocclusion, continuous monitoring of the three-dimensional relationship between dental roots and the surrounding alveolar bone is essential for preventing complications from orthodontic procedures. Cone-beam computed tomography (CBCT) provides detailed root and bone data, but its high radiation dose limits its frequent use, consequently necessitating an alternative for ongoing monitoring. ObjectivesWe aimed to develop a deep learning-based cross-temporal multimodal image fusion system for acquiring root and jawbone information without additional radiation, enhancing the ability of orthodontists to monitor risk. MethodsUtilizing CBCT and intraoral scans (IOSs) as cross-temporal modalities, we integrated deep learning with multimodal fusion technologies to develop a system that includes a CBCT segmentation model for teeth and jawbones. This model incorporates a dynamic kernel prior model, resolution restoration, and an IOS segmentation network optimized for dense point clouds. Additionally, a coarse-to-fine registration module was developed. This system facilitates the integration of IOS and CBCT images across varying spatial and temporal dimensions, enabling the comprehensive reconstruction of root and jawbone information throughout the orthodontic treatment process. ResultsThe experimental results demonstrate that our system not only maintains the original high resolution but also delivers outstanding segmentation performance on external testing datasets for CBCT and IOSs. CBCT achieved Dice coefficients of 94.1 % and 94.4 % for teeth and jawbones, respectively, and it achieved a Dice coefficient of 91.7 % for the IOSs. Additionally, in the context of real-world registration processes, the system achieved an average distance error (ADE) of 0.43 mm for teeth and 0.52 mm for jawbones, significantly reducing the processing time. ConclusionWe developed the first deep learning-based cross-temporal multimodal fusion system, addressing the critical challenge of continuous risk monitoring in orthodontic treatments without additional radiation exposure. We hope that this study will catalyze transformative advancements in risk management strategies and treatment modalities, fundamentally reshaping the landscape of future orthodontic practice.

Morphological Analysis of the Anatomical Mandibular Lingual Concavity Using Cone Beam Computed Tomography Scans in East Asian Population-A Retrospective Study.

The rising demand for dental implants necessitates addressing anatomical challenges, particularly the shape of the mandible. Incorrectly angling implants can cause lingual perforations, risking damage to the inferior alveolar artery and nerve. This study analyzed 96 cone-beam computed tomography images from individuals aged 20 to 70 (8 males and 8 females) to evaluate mandibular anatomy in four areas: left and right sides and the first and second molars. Mandibular shapes were classified into U, C, and P types. U-shaped mandibles, with a wider crest width, pose the highest risk of lingual perforation. Measurements for U-shaped types included concavity angle, length, and depth. Statistical analyses (T-tests and ANOVA) with a 95% confidence interval showed no significant differences between the left and right sides. However, significant differences based on gender, age, and tooth type were found. The study found U-shapes in 34.6% of cases, P-shapes in 28.9%, and C-shapes in 36.5%, with U-shapes more common in second molars. Understanding these variations enhances the safety and effectiveness of implant procedures and oral surgeries.

Endodontic Microsurgery Using Dynamic Navigation and Trephine Burs

Objectives: The use of the surgical operating microscope, CBCT imagining, biocompatible filling materials and ultrasonic instruments have improved the success and predictability of apical surgery. Despite these advances, more accurate and precise techniques for creating osteotomies and root-resections (apicoectomies) have not been widely adopted. This study highlights how dynamic navigation systems (DNS) can help avoid unnecessary dentin removal and “mitigate iatrogenic errors” such as root perforation. Methods: A total of 56 root-end resections were planned and completed on two sets of identical TrueJaw Endosurg models (DE Labs, Santa Barbra, CA, USA). One set of maxillary and mandibular jaws were used for 28 preparations, performed with a DNS (X-Guide, X-Nav Technologies, Lansdale, PA, USA). A second set of maxillary and mandibular jaws were used for 28 preparations executed freehand (FH), with pre-op measurements taken from a CBCT scan (CS 9600; Carestream, Atlanta, GA, USA). A Mann-Whitney test was used to compare the accuracy of the two groups Results: The average preparation depth was 10.77 mm. For the DNS group the average angular deviation was 2.35 degrees. The average deviation at the terminal end of the preparations was 0.96 mm (global apical deviation). For the freehand group average angular deviation was 13.55 degrees and the average global apical deviation was 2.62 mm. Significant differences were identified between the DNS and FH groups for angular deviation (p<0.05), apical non-depth deviation (p<0.05) and between the Global apical deviation(p<0.05). Conclusion: Dynamic navigation demonstrated superior accuracy and precision over freehand in the context of apical microsurgery preparations. This study provides further proof of concept for the application of DNS in Endodontics. Clinical significance: Apical surgery can be a daunting task for an endodontist. Surgical guides can make the procedure easier, but they take time and money to make. DNS virtual planning can be completed rapidly and may be altered mid-procedure. This inherent flexibility makes same-day guided apical surgeries practical and predictable.

Assessment of the application of a novel three-dimension printing individualized titanium mesh in alveolar bone augmentation: A retrospective study.

To assess the clinical and radiographic outcomes of alveolar ridge augmentation using a novel three-dimensional printed individualized titanium mesh (3D-PITM) for guided bone regeneration (GBR). Preoperative cone-beam computed tomography (CBCT) was used to evaluate alveolar ridge defects, followed by augmentation with high-porosity 3D-PITM featuring circular and spindle-shaped pores. Postoperative CBCT scans were taken immediately and after 6 months of healing. These scans were compared with preoperative scans to calculate changes in bone volume, height, and width, along with the corresponding resorption rates. A statistical analysis of the results was then conducted. A total of 21 patients participated in the study, involving alveolar ridge augmentation at 38 implant sites. After 6 months of healing, the average bone augmentation volume of 21 patients remained at 489.71 ± 252.53 mm3, with a resorption rate of 16.05% ± 8.07%. For 38 implant sites, the average vertical bone increment was 3.63 ± 2.29 mm, with a resorption rate of 17.55% ± 15.10%. The horizontal bone increment at the designed implant platform was 4.43 ± 1.85 mm, with a resorption rate of 25.26% ± 15.73%. The horizontal bone increment 2 mm below the platform was 5.50 ± 2.48 mm, with a resorption rate of 16.03% ± 9.57%. The main complication was exposure to 3D-PITM, which occurred at a rate of 15.79%. The novel 3D-PITM used in GBR resulted in predictable bone augmentation. Moderate over-augmentation in the design, proper soft tissue management, and rigorous follow-ups are beneficial for reducing the graft resorption and the incidence of exposure.

Variations in head tilt during the acquisition of CBCT scans and their effects on effective radiation dose.

This study evaluated the impact of variations in anteroposterior and lateral tilts of patients' head on radiation-weighted doses to organs/tissues and effective doses using three different cone beam computed tomography machines. An anthropomorphic phantom was used to estimate radiation doses in three CBCT machines (OP300, Eagle X 3D, and Eagle Edge). Thermoluminescent dosimeters were placed in regions corresponding to pre-stablished organ/tissues. CBCT examinations from the posterior mandible and anterior maxilla regions were acquired, with three different anteroposterior angulations (0°, 30°, and 45°), and from the posterior mandible in three different lateral angulations (0°, 20° to the left, and 20° to the right side). Radiation-weighted doses for each organ/tissue and effective doses were calculated for each machine and angulation. For the posterior mandible acquisitions, anteroposterior angulations of the head at 30° and 45° yielded a reduction in effective doses in all three devices. A 20° tilt to the right side resulted in lower doses than to the left (same side as the FOV). For the anterior maxilla, increased anteroposterior angulation was associated with reduction in effective dose in two devices. Effective doses are lower when small FOV CBCT exams of the posterior mandible and anterior maxilla are acquired with increased anteroposterior head angulation at 30° and 45°. For FOV in the posterior mandible, a 20° lateral tilt towards the side opposite to the FOV also yields lower effective doses. The main contribution to these dose reductions is the decrease in dose to salivary glands.

Automatic segmentation of dental cone-beam computed tomography scans using a deep learning framework

Bevezetés: A ’cone-beam’ (kúpsugaras) számítógépes tomográfiás (CBCT) felvételek szegmentációja során a síkbeli képekből álló adatokat három dimenzióban (3D) rekonstruáljuk. A szájsebészetben és a parodontológiában a digitális adatfeldolgozás lehetővé teszi a műtéti beavatkozások 3D tervezését. A leggyakrabban alkalmazott határérték-alapú szegmentáció gyors, de pontatlan, míg a félautomatikus módszerek megfelelő pontosságúak, de rendkívül időigényesek. Az utóbbi években a mesterséges intelligencián alapuló technológiák elterjedésével azonban mostanra lehetőség van a CBCT-felvételek automatikus szegmentációjára. Célkitűzés: A klinikai gyakorlatból vett CBCT-felvételeken betanított mélytanulási szegmentációs modell bemutatása és hatékonyságának vizsgálata. Módszer: A vizsgálat három fő fázisa volt: a tanuló adatbázis felállítása, a mélytanulási modell betanítása és ezen architektúra pontosságának tesztelése. A tanuló adatbázis felállításához 70, részlegesen fogatlan páciens CBCT-felvételeit alkalmaztuk. A SegResNet hálózati architektúrára épülő szegmentációs modellt a MONAI rendszer segítségével fejlesztettük ki. A mélytanulási modell pontosságának ellenőrzéséhez 15 CBCT-felvételt használtunk. Ezeket a felvételeket a mélytanulási modell segítségével, valamint félautomatikus szegmentációval is feldolgoztuk, és összehasonlítottuk a két szegmentáció eredményét. Eredmények: A mélytanulásos szegmentáció és a félautomatikus szegmentáció közötti hasonlóság a Jaccard-index szerint átlagosan 0,91 ± 0,02, a Dice hasonlósági együttható átlagos értéke 0,95 ± 0,01, míg a két modell közötti átlagos Hausdorff- (95%) távolság 0,67 mm ± 0,22 mm volt. A mélytanulásos architektúra által szegmentált és a félautomatikus szegmentációval létrehozott 3D modellek térfogata nem mutatott statisztikailag szignifikáns különbséget (p = 0,31). Megbeszélés: A vizsgálatunkban használt mélytanulási modell az irodalomban található mesterségesintelligencia-rendszerekhez hasonló pontossággal végezte el a CBCT-felvételek szegmentációját, és mivel a CBCT-felvételek a rutin klinikai gyakorlatból származtak, a mélytanulási modell relatíve nagy megbízhatósággal szegmentálta a parodontalis csonttopográfiát és az alveolaris gerincdefektusokat. Következtetés: A mélytanulási modell nagy pontossággal szegmentálta az alsó állcsontot dentális CBCT-felvételeken. Ezek alapján megállapítható, hogy a mélytanulásos szegmentációval előállított 3D modell alkalmas lehet rekonstruktív szájsebészeti és parodontalis sebészeti beavatkozások digitális tervezésére. Orv Hetil. 2024; 165(32): 1242–1251.

Evaluation of the accuracy of cone beam computed tomography (CBCT) in the detection of peri-implant fenestration

BackgroundAccurate assessment of the bone supporting the implant is crucial. Early detection of bone defects around the implant can prevent the loss of bone support that ultimately leads to the loss of the implant. Therefore, the purpose of this study is to check the accuracy of CBCT in detecting peri-implant fenestrations around the implant.Materials & methodsIn this laboratory study, healthy beef ribs were used. The ribs were divided into three groups of 12 (control group, 1–2 mm fenestration group, and 2–3 mm fenestration group). The blocks were cut to a length of 20 mm and 36 osteotomies with dimensions of 4 × 12 mm were made by the periodontist in order to place the implant in these bone blocks. Then the titanium implant was placed in the holes and the initial scan was performed with CBCT. In the second group, fenestration-like lesions were created on the same buccal side at a distance of 10 mm from the crest with a diameter of 1–2 mm and in the third group with a diameter of 2–3 mm, and the CBCT scan was performed again with the same parameters. Two radiologists evaluated the images twice for the presence and absence of fenestration.ResultsThere was no statistically significant difference between direct measurements and CBCT in the fenestration group of 1–2 mm (p < 0.05), but there was a significant difference between direct measurements and CBCT in the fenestration group of 2–3 mm and underestimation was observed in CBCT measurements.ConclusionThe findings of this study showed that CBCT radiography has a higher accuracy in measuring the fenestration around the implant with a smaller diameter and has an acceptable diagnostic value in detecting bone loss around the implant.

Validation of a novel AI-based automated multimodal image registration of CBCT and intraoral scan aiding presurgical implant planning.

The objective of this study is to assess accuracy, time-efficiency and consistency of a novel artificial intelligence (AI)-driven automated tool for cone-beam computed tomography (CBCT) and intraoral scan (IOS) registration compared with manual and semi-automated approaches. A dataset of 31 intraoral scans (IOSs) and CBCT scans was used to validate automated IOS-CBCT registration (AR) when compared with manual (MR) and semi-automated registration (SR). CBCT scans were conducted by placing cotton rolls between the cheeks and teeth to facilitate gingival delineation. The time taken to perform multimodal registration was recorded in seconds. A qualitative analysis was carried out to assess the correspondence between hard and soft tissue anatomy on IOS and CBCT. In addition, a quantitative analysis was conducted by measuring median surface deviation (MSD) and root mean square (RMS) differences between registered IOSs. AR was the most time-efficient, taking 51.4 ± 17.2 s, compared with MR (840 ± 168.9 s) and SR approaches (274.7 ± 100.7 s). Both AR and SR resulted in significantly higher qualitative scores, favoring perfect IOS-CBCT registration, compared with MR (p = .001). Additionally, AR demonstrated significantly superior quantitative performance compared with SR, as indicated by low MSD (0.04 ± 0.07 mm) and RMS (0.19 ± 0.31 mm). In contrast, MR exhibited a significantly higher discrepancy compared with both AR (MSD = 0.13 ± 0.20 mm; RMS = 0.32 ± 0.14 mm) and SR (MSD = 0.11 ± 0.15 mm; RMS = 0.40 ± 0.30 mm). The novel AI-driven method provided an accurate, time-efficient, and consistent multimodal IOS-CBCT registration, encompassing both soft and hard tissues. This approach stands as a valuable alternative to manual and semi-automated registration approaches in the presurgical implant planning workflow.

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

To evaluate the morphology of the mastoid process and its role in sex determination with the help of cone-beam computed tomography (CBCT). 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. 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. 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%. 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.

Technical note: Phantom-based evaluation of CBCT dose calculation accuracy for use in adaptive radiotherapy.

High-quality 3D-anatomy of the day is needed for treatment plan adaptation in radiotherapy. For online x-ray-based CBCT workflows, one approach is to create a synthetic CT or to utilize a fan-beam CT with corresponding registrations. The former potentially introduces uncertainties in the dose calculation if deformable image registration is used. The latter can introduce burden and complexity to the process, the facility, and thepatient. Using the CBCT of the day, acquired on the treatment device, for direct dose calculation and plan adaptation can overcome these limitations. This study aims to assess the accuracy of the calculated dose on the CBCT scans acquired on a Halcyon linear accelerator equipped withHyperSight. HyperSight's new CBCT reconstruction algorithm includes improvements in scatter correction, HU calibration of the imager, and beam shape adaptation. Furthermore, HyperSight introduced a new x-ray detector. To show the effect of the implemented improvements, gamma comparisons of 2%/2mm, 2%/1mm, and 1%/1mm were made between the dose distribution in phantoms calculated on the CBCT reconstructions and the simulation CT scans, considering this the standard of care. The resulting gamma passing rates were compared to those obtained with the Halcyon 3.0 reconstruction and hardware without HyperSight's technologies. Various anatomical phantoms for dosimetric evaluations on brain, head and neck, lung, breast, and prostate cases have been used in thisstudy. The overall results demonstrated that HyperSight outperformed the Halcyon 3.0 version. Based on the gamma analysis, the calculated dose using HyperSight was closer to the CT scan-based doses than the calculated dose using iCBCT Halcyon 3.0 for most cases. Over all plans and gamma criteria, Halcyon 3.0 achieved an average passing rate of 92.9%, whereas HyperSight achieved 98.1%. Using HyperSight CBCT images for direct dose calculation, for example, in (online) plan adaptation, seems feasible for the investigatedcases.

Treatment Reproducibility in Brain Stereotactic Radiotherapy Using a Shim Mask Versus a Standard Mask.

Introduction This study aimed to evaluate the setup accuracy of the new shim mask with mouth bite compared to the standard full brain mask in stereotactic radiosurgery (SRS) and radiotherapy (SRT) treatments for brain metastases or tumors. Method A combined retrospective and prospective design was employed, involving 40 patients treated at our center. Patients previously treated using standard head masks formed the retrospective cohort, while those treated with the Shim mask and mouth bite formed the prospective cohort. Daily cone-beam computed tomography (CBCT) scans were obtained before each treatment session to ensure patient setup accuracy. Key metrics included absolute shifts in translational and rotational directions, the number of repeat CBCTs, and the time interval between CBCTs. Results The Shim mask significantly reduced the mean setup errors in the lateral translation (p=0.022) from 0.17 cm (SD=0.10) to 0.10 cm (SD=0.10), and in X-axis rotation (p=0.030) from 0.79° (SD=0.43) to 0.47° (SD=0.47). By considering cutoff points of 1 mm in translational and 1° in rotational directions, the Shim mask was significantly more accurate in the lateral direction (p=0.004). Moreover, while 70% of patients in the standard group required repeat CBCT scans, none in the Shim group did, resulting in an average time saving of 10.4 minutes per patient. Conclusion The Shim mask with mouth bite offers enhanced immobilization accuracy in SRT/SRS treatments, leading to time and potential cost savings by reducing the need for repeat CBCT scans. This underscores the importance of adopting innovative immobilization techniques to optimize patient outcomes.

Three-Dimensional Analysis of the Maxillary Sinuses in Ancient Crania Dated to the V-VI Centuries BCE from Opi (Italy): Volumetric Measurements in Ancient Skulls from the Necropolis of Opi, Abruzzi, Italy.

Cone beam computed tomography (CBCT) can provide precise information about complex anatomical structures as it is characterised by rapid volumetric image acquisition with high resolution. The aim of this study was to provide measurements for 20 ancient skulls of the Samnite people found in the necropolis of Opi, a small and isolated mountain village in Abruzzo, a region in central Italy. All the images (left and right) of the 20 ancient skulls from Opi were acquired. All the data are the property of the Department of Innovative Technologies in Medicine and Dentistry of G. D'Annunzio University, Chieti, and different parameters (area and volume) were measured and evaluated. The mean and standard deviation of the facial measurements were also calculated. All the data were subjected to statistical analysis. CBCT scan data of 20 fossil skulls did not show significant values regarding the MS area and the volume between the right and left sides. In the ancient skulls, no difference was found between the right and left sides.

Leveraging Pretrained Transformers for Efficient Segmentation and Lesion Detection in Cone-Beam Computed Tomography Scans

IntroductionCone-beam computed tomography (CBCT) is widely used to detect jaw lesions, although CBCT interpretation is time-consuming and challenging. Artificial intelligence for CBCT segmentation may improve lesion detection accuracy. However, consistent automated lesion detection remains difficult, especially with limited training data. This study aimed to assess the applicability of pretrained transformer-based architectures for semantic segmentation of CBCT volumes when applied to periapical lesion detection. MethodsCBCT volumes (n = 138) were collected and annotated by expert clinicians using 5 labels – "lesion," "restorative material," "bone," "tooth structure," and "background." U-Net (convolutional neural network-based) and Swin-UNETR (transformer-based) models, pretrained (Swin-UNETR-PRETRAIN), and from scratch (Swin-UNETR-SCRATCH), were trained with subsets of the annotated CBCTs. These models were then evaluated for semantic segmentation performance using the Sørensen–Dice coefficient (DICE), lesion detection performance using sensitivity and specificity, and training sample size requirements by comparing models trained with 20, 40, 60, or 103 samples. ResultsTrained with 103 samples, Swin-UNETR-PRETRAIN achieved a DICE of 0.8512 for "lesion," 0.8282 for "restorative materials," 0.9178 for "bone," 0.9029 for "tooth structure," and 0.9901 for "background." “Lesion” DICE was statistically similar between Swin-UNETR-PRETRAIN trained with 103 and 60 images (P > .05), with the latter achieving 1.00 sensitivity and 0.94 specificity in lesion detection. With small training sets, Swin-UNETR-PRETRAIN outperformed Swin-UNETR-SCRATCH in DICE over all labels (P < .001 [n = 20], P < .001 [n = 40]), and U-Net in lesion detection specificity (P = .006 [n = 20], P = .031 [n = 40]). ConclusionsTransformer-based Swin-UNETR architectures allowed for excellent semantic segmentation and periapical lesion detection. Pretrained, it may provide an alternative with smaller training datasets compared to classic U-Net architectures.

Correlation Between Radiological Changes of the Temporomandibular Joint and Upper Cervical Vertebrae in Degenerative Joint Disease: A Cone-Beam Computed Tomography-Based Analytical Study.

Objectives This study was conducted to assess the radiological changes of the temporomandibular joint (TMJ) and cervical vertebrae individually and their correlation in degenerative joint disease (DJD) using a cone-beam computed tomography (CBCT)-based approach. Methodology The study employed a cross-sectional, analytical retrospective design, analyzing one-year data. CBCT scans of 60 patients (120 TMJs) were assessed for degenerative changes using standardized imaging parameters. Eligibility criteria included full field-of-view CBCT scans, excluding those with craniofacial anomalies or prior orthodontic treatment. Radiological assessments of TMJs and cervical vertebrae were conducted by experienced radiologists using the Anjos Pontual method and novel grading system (TMJ Spine Degenerative Severity Index). Results The study included 60 CBCT scans (120 joints), with 31.7% males and 68.3% females. Participants were predominantly aged 31-60 years (58.3%). DJDfindings for the right TMJ showed grade 1 changes in 55.0% and grade 2 in 31.7%, while the left TMJ had 46.7% grade 1 and 35.0% grade 2 changes. A strong positive correlation (0.704) was found between bilateral TMJ and cervical vertebrae changes. Age correlated significantly with TMJ alterations but not with cervical vertebrae changes. Conclusion This study demonstrated that there exists a positive association between the radiological changes of TMJ and cervical vertebrae in DJD with age, which can be detected in mild stage of severity on CBCTand can be of use in clinical correlation and application of optimal interventions ensuring better prognosis.

Correction of scatter in CBCT with a new grid design

Objective. This study aims at developing a simple and rapid Compton scatter correction approach for cone-beam CT (CBCT) imaging. Approach. In this work, a new Compton scatter estimation model is established based on two distinct CBCT scans: one measures the full primary and scatter signals without anti-scatter grid (ASG), and the other measures a portion of primary and scatter signals with ASG. To accelerate the entire data acquisition speed, a half anti-scatter grid (h-ASG) that covers half of the full detector surface is proposed. As a result, the distribution of scattered x-ray photons could be estimated from a single CBCT scan. Physical phantom experiments are conducted to validate the performance of the newly proposed scatter correction approach. Main results. Results demonstrate that the proposed half grid approach can quickly and precisely estimate the distribution of scattered x-ray photons from only one single CBCT scan, resulting in a significant reduction of shading artifacts. In addition, it is found that the h-ASG approach is less sensitive to the grid transmission fractions, grid ratio and object size, indicating a robust performance of the new method. Significance. In the future, the Compton scatter artifacts can be quickly corrected using a half grid in CBCT imaging.

Anatomical characteristics of mental foramen and canal: A cone-beam computed tomography analysis.

So far, different studies have endeavored to evaluate the position and dimensions of mental foramen and canal using cone-beam computed tomography (CBCT) images with various results. This study aimed to assess the anatomical variations of the mental foramen and canal utilizing CBCT images. In this retrospective observational study, we investigated CBCT scans of 355 patients (710 terminal branches of mental canal and foramen) who were referred to a private dental and maxillofacial radiology center in Babol, during 2020-2022. We recorded different anatomical variations of mental foramina and canals on left (n=355) and right (n=355) mandibles. Most of the mental canals had a distal opening (n=334, 47.0%). The distance between the mental foramen and the lower mandibular border was greater on left mandible (13.92±3.73 mm) than on the right mandible (12.25±3.94 mm) (p<0.001). On left mandible, the vertical diameter of the mental foramen, as well as the distance between the mental foramen and the lower mandibular border, were significantly greater in men than in women. On right mandible, the distance between the mental foramen and the upper alveolar crest edge, as well as the distance between the mental foramen and the lower mandibular border, were significantly greater in men versus women. Finally, on right mandible, the vertical diameter of the mental foramen was significantly greater in subjects aged >45 years compared with those aged ≤45 (p=0.024). There were notable variations in the morphological characteristics of the mental foramen and canal, which should be considered by clinicians. Key words:Mental foramen, mental canal, cone-beam computed tomography.

Exploring the age and gender-based distribution of paranasal sinus osteomas using cone beam computed tomography: A retrospective cross-sectional study

ObjectiveThe objective of this study is to explore the prevalence, size, location and radiographic features of osteomas in the paranasal sinuses using cone beam computed tomography imaging. Study designThis study was planned as retrospective cross-sectional. 499 consecutive cone beam computed tomography scans obtained in a dentomaxillofacial radiology department for various dental indications. Statistical analysis of all data was done with SPSS version 22. Descriptive statistics and chi-square tests were used to determine the prevalence of categorical parameters. ResultsOsteoma was detected in 7 % (n = 35) of the 499 images analyzed. The age of the patients ranged from 6 to 96 years (mean 42.03 ± 18.70). No significant difference was found between the genders (p = 0.77). In terms of localization, it was significantly more common in the ethmoid sinuses (p < 0.01). Cortical type osteoma was observed the most frequently in the analyzed images (p < 0.01). The incidence of osteoma was not significant depending on age (p = 0.50). ConclusionOsteomas in the paranasal sinuses show a 7 % prevalence in CBCT images, with the ethmoid sinus being the most common site. The average size of osteomas was 3.43 ± 1.78 mm, predominantly cortical in type. These findings highlight the necessity for thorough examination of CBCT images by dentomaxillofacial radiologists to avoid overlooking osteomas.

Gender-Specific Variations in Greater Palatine Foramen Anatomy: Insights from CBCT Scans in the North Cyprus Population.

BACKGROUND The greater palatine foramen (GPF) is anatomically located distal to the third maxillary molar tooth, midway between the midline of the palate and the dental arch. The GPF contains the major palatine artery, vein, and nerve, traversing the palatine sulcus. This study aimed to evaluate the anatomical position of the GPF in 93 women and 67 men at a single center in Cyprus using cone beam computed tomography (CBCT). MATERIAL AND METHODS A retrospective analysis was conducted on 160 CBCT scans. Measurements of the GPF's horizontal and vertical diameters, distances from GPF to the incisive foramen, posterior nasal spine, anterior nasal spine, and midaxillary suture, and positional relationships to molars were recorded. Statistical analyses compared these measurements between males and females. RESULTS The study included 93 females and 67 males with an average age of 46.6 (±11.6) years. Significant sex differences were observed in most GPF measurements, with males showing larger dimensions such as the anterior nasal spine, posterior nasal spine, mid-maxillary suture, and incisive foramen to the GPF. The GPF was predominantly located in the third molar region (96.25% on the right, 96.9% on the left). The left GPF showed a significantly larger horizontal diameter than the right (P<0.05). CONCLUSIONS There was a significant difference in the average distances from the anterior nasal spine, posterior nasal spine, mid-maxillary suture, and incisive foramen to the GPF, as well as in the size of the GPF, between males and females. Recognizing these variations enhances clinical planning and reduces the risk of complications.

Alveolar ridge bone changes in patients treated with the split-crest technique with simultaneous implant placement: Aretrospective longitudinal observational study.

To investigate long-term alveolar ridge bone changes in patients treated with the split-crest technique (SCT) with simultaneous implant placement. Alveolar ridge width (ARW) was measured with a caliper immediately before (ARW1) and after SCT (ARW2) with a caliper. Existing CBCT scans taken at least 5 years postoperatively were used to assess the healed ARW (ARWF), buccal bone thickness (BBT), and lingual/palatal bone thickness (L/PBT) at 0, 3, and 5 mm apically from implant platform level (IPL). The distance between IPL and buccal bone crest (IPL-BBC) was also measured. Findings were compared with Wilcoxon and Student's t tests (p < .05). Records of thirty patients with 85 implants were included. Eleven patients (31 implants) presented CBCT scans taken in two separate occasions, resulting in 116 measurements. Tomographic follow-up ranged from 5 to 18 years (11.5 ± 4.18 years). Mean ARW increased from 3.2 ± 0.6 to 6.6 ± 0.48 mm after SCT, but significantly reduced overtime to 4.46 ± 0.83 mm (ARWF) (p < .0001). Mean BBT was 0.5 ± 0.9, 1.3 ± 0.9, and 2.0 ± 1.2 mm, while mean L/PBT was 0.9 ± 0.7, 1.6 ± 0.9, and 2.1 ± 1.0 mm at 0, 3, and 5 mm from IPL, respectively. IPL-BBC distance varied up to 8.7 mm (1.4 ± 2.0 mm), with 56/116 measurements (51/85 implants) showing IPL-BBC = 0 mm. Although SCT with simultaneous implant placement can predictably increase ARW postoperatively, ARW tended to significantly reduce over time, due to reductions in BBT and L/PBT, especially coronally. Nonetheless, 60% of the implants still presented some buccal bone at IPL.

A novel digital way to measure the vertical and horizontal dimensions of the supra-crestal peri-implant soft tissues.

To report on a novel digital superimposition workflow that enables measuring the supra-crestal peri-implant soft tissue dimensions all along implant treatment and afterwards. A preoperative CBCT and intra-oral scans (IOS) are successively taken before surgery, at the end of the healing period, at prosthesis delivery, and over time; they are digitally superposed on a dedicated software. Then, the stereolithography files (STL) of the healing abutment, of the prosthetic abutment and the crown are successively merged into the superposition set of IOSs. The workflow protocol of merging successively the STL of each item into the superposition set of IOSs enables capturing the dimensions of the height and width of the supra-crestal soft tissues, at every level of the healing abutment, the prosthetic abutment and the crown. In addition, it allows measuring the vertical distance that the crown exerts pressure on the gingiva and the thickness of the papillae at every level of the abutment. This novel digital superimposition workflow provides a straightforward method of measuring the vertical and horizontal dimensions of the supra-crestal peri-implant soft tissues, including the papillae, at each stage of the implant treatment process. It allows investigating a certain number of soft tissue variables that were previously inaccessible to clinical research. It should help enhancing our comprehension of the peri-implant soft tissue dynamics.