Cone Beam Computed Tomography Scans Research Articles

The Application of Mask Region-Based Convolutional Neural Networks in the Detection of Nasal Septal Deviation Using Cone Beam Computed Tomography Images: Proof-of-Concept Study.

Artificial intelligence (AI) models are being increasingly studied for the detection of variations and pathologies in different imaging modalities. Nasal septal deviation (NSD) is an important anatomical structure with clinical implications. However, AI-based radiographic detection of NSD has not yet been studied. This research aimed to develop and evaluate a real-time model that can detect probable NSD using cone beam computed tomography (CBCT) images. Coronal section images were obtained from 204 full-volume CBCT scans. The scans were classified as normal and deviated by 2 maxillofacial radiologists. The images were then used to train and test the AI model. Mask region-based convolutional neural networks (Mask R-CNNs) comprising 3 different backbones-ResNet50, ResNet101, and MobileNet-were used to detect deviated nasal septum in 204 CBCT images. To further improve the detection, an image preprocessing technique (contrast enhancement [CEH]) was added. The best-performing model-CEH-ResNet101-achieved a mean average precision of 0.911, with an area under the curve of 0.921. The performance of the model shows that the model is capable of detecting nasal septal deviation. Future research in this field should focus on additional preprocessing of images and detection of NSD based on multiple planes using 3D images.

Evaluation of imaging dose for the cone beam computed tomography system of the ring-shaped radiotherapy unit using the different International Electrotechnical Commission approaches

PurposeDaily imaging is mandatory for the Halcyon and Ethos, which are the new ring-shaped radiotherapy units. This study quantified the imaging dose of the cone beam computed tomography (CBCT) system of the new ring-shaped radiotherapy units using the latest International Electrotechnical Commission (IEC) measurement approach. Furthermore, we investigated the influence of collimation width on the imaging dose and compared the imaging dose values obtained using three IEC measurement approaches. MethodsThe IEC has proposed three approaches for measuring CTDI100: traditional, transition, and the latest measurement approach. In addition to the dose measured on the CTDI phantom, the latest IEC approach uses correction factors measured in free air for CTDI100 measurement. The imaging dose was measured for all scanning protocols using the latest IEC approach. To investigate the influence of the collimation width on the imaging dose, the associated dose metric values were evaluated and compared using different IEC approaches to increase the collimation width (2–28 cm). Furthermore, the imaging system output stability was evaluated by repeated measurements. ResultsIn the repeated measurements, the standard deviation of CTDIw value for the pelvis and head protocol was 0.05 mGy and 0.01 mGy, respectively. And the coefficient of variation was 0.21% and 0.23%, respectively. The measured CTDIw values of the clinical protocols were higher than the vendor-provided value, except for the pelvis protocol. The value of CTDIw changes little with increasing collimation width using the latest IEC approach. The traditional and transition approaches either underestimated or overestimated the value of CTDIw, as measured by the latest IEC approach, with increasing collimation width. ConclusionsThe new ring-shaped radiotherapy units imaging system has good output stability. The CTDIw values measured for clinical scanning protocols generally exceeded the vendor-provided values. Compared with the latest IEC CTDI100 measurement approach, the traditional and transition measurement approaches were more influenced by beam width. For wide CBCT scans, rationalizing the choice of imaging dose measurement approach is important.

A study on the precision of voxel- and surface-based mandibular superimposition.

To apply the more accurate technique for mandibular superimposition and provide a valuable reference for the assessment of mandibular tooth movement and condylar remodeling before and after orthodontic treatment. This retrospective study involved 38 adult patients who underwent two cone beam computer tomography (CBCT) scans at different stages of treatment at Fujian Provincial People's Hospital between September, 2020 and December, 2022. The software Dolphin was used for mandible segmentation, enabling voxel-based mandibular superimposition with the mandibular ramus as the reference region. The Geomagic Wrap software was employed to process surface-based mandibular superimposition with the mandibular ramus as a reference. Additionally, the voxel and surface-based methods were compared for precision, with the mandibular ramus being the reference. After voxel-based mandibular superimposition using the mandibular ramus as a reference, with all measurement errors (< 0.20 mm). In contrast, the results of surface-based mandibular superimposition with the same reference, and the measurement errors were all less than 0.10 mm. The Wilcoxon signed-rank test revealed statistically significant differences between AS1 and BS1, AS2 and BS2, AS3 and BS3, and AS4 and BS4 (all r< 0.05). Moreover, the absolute mean distances of AS1-AS4 were all greater than those of BS1-BS4. All mandibular superimposition procedures, including the voxel- and surface-based ones using the mandibular ramus as a reference, have acceptable surface errors (< 0.20 mm), indicating the good reliability of these techniques. Under the specified conditions, surface-based mandibular superimposition appears to yield a higher degree of precision compared with the voxel-based technique.

Association between maxillary incisor width and craniofacial measurements: A cone beam computed tomography study

Accurate prediction of maxillary central incisor width (CIW) is essential in prosthodontics for selecting appropriately sized denture teeth. While traditional methods exist, the digital era may offer more reliable techniques for anterior tooth selection. The purpose of this study was to investigate the correlation between CIW and craniofacial measurements derived from cone beam computed tomography (CBCT) scans to identify predictors for CIW and examine possible sexual dimorphism. A retrospective analysis was conducted on 80 three-dimensional skull models (40 men, 40 women; age range: 20 to 48 years) generated from segmented CBCT scans. Measurements included CIW, interpterygoid hamulus distance, bi-orbital width, interorbital distance, and piriform aperture width. Statistical analyses comprised independent t tests, bivariate correlations, and multiple linear regression (α=.05). Significant sexual dimorphism was observed in CIW, interpterygoid hamulus distance, and bi-orbital width (P<.05). CIW positively correlated with bi-orbital width (r=.75, P<.001) and piriform aperture width (r=.49, P<.001). Multiple regression analysis revealed bi-orbital width, and interorbital distance, along with sex, as significant predictors of CIW (R²=.59, P<.001). Bony bi-orbital width, interorbital distance, and sex can be used to estimate the maxillary CIW.

Middle mesial canal incidence and morphology in mandibular first molars: A cone-beam computed tomography and micro-computed tomography evaluation.

Mandibular first molar (MFM) being the first permanent posterior tooth to erupt, quite often gets involved in dental caries, which subsequently requires endodontic treatment in many cases. Thus, it is essential that the clinicians be aware of the root canal and the morphology of these teeth in detail. Over a period of years, the cases reporting with middle mesial canals (MMCs) in the MFMs have been seen on the rise; thus, it is imperative to know its incidence so that the data can be passed on to the clinicians for better management. The aim of the current research was to evaluate the incidence of MMC in the MFMs using cone-beam computed tomography (CBCT) and further evaluating its morphology with micro-computed tomography (micro-CT). Five hundred and fifty extracted permanent MFMs were collected and subjected to CBCT scan. The teeth in which MMC was found, were further subjected to micro-CT to evaluate the detailed morphology. The data exhibited the presence of MMC in 29 teeth out of 550 (5.27%). The most frequent morphological pattern observed in the MMC as per micro-CT was the confluent type (86.2%), followed by independent type (6.8%) and fin type (3.4%). Double MMC was observed in 1 tooth (3.4%). The incidence of MMC was observed to be 5.27% and the confluent type of morphological configuration was the most common type noticed.

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

ObjectivesThis 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 methodsThe 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. ResultsSG 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. ConclusionIndividuals 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.

Application of Cone-Beam Computed Tomography-Generated Cephalograms in Children and Adolescents

This study investigates the potential of cone-beam computed tomography (CBCT)-generated cephalograms as a replacement for conventional lateral cephalograms (LCs) in children and adolescents. This retrospective study included 60 individuals, equally divided into permanent and mixed dentition groups. Both groups underwent conventional LCs and CBCT scans on the same day. LCs were then derived from CBCT scans. The same examiner performed digital measurements twice, with a week’s interval, identifying landmarks and obtaining 7 angular and 5 linear measurements. In the permanent dentition group, significant differences were observed between the two imaging modalities for 6 angular and 2 linear measurements. In the mixed dentition group, significant differences were observed for 3 angular and 2 linear measurements. However, none of these differences exceeded the clinically acceptable limit of 2.0º or 2.0 mm. No significant differences in any measurement were found between the two groups (&lt;i&gt;p&lt;/i&gt; &lt; 0.05). CBCT-generated LCs demonstrated comparable results with good reliability in both dentition groups, suggesting their potential as suitable alternatives for children and adolescents who require CBCT for clinical purposes.

Evaluation of Anatomical Landmark Consistency in the Auditory Meatus Using Cone-Beam Computed Tomography (CBCT) Imaging

IntroductionThe present study evaluated the consistency and reliability of five anatomical landmarks in the external auditory meatus using CBCT (cone beam computed tomography) scans. The goal was to determine if these landmarks could reliably replace the commonly used point Porion for superimposing CBCT scans in clinical practice. Consistent anatomical features in the external auditory meatus are essential for accurate cranial assessments in dentistry and medicine. Despite their importance, these features have been underexplored, making this study a valuable contribution to improving clinical evaluation accuracy. Materials and methods22 CBCT scans were analyzed using ITK-Snap software. The shape of the External Auditory Meatus had been rendered by segmentation. These segmentations were used as a basis to locate the landmarks. The spread in location of the suggested landmarks concerning a reference coordinate system was treated as a measure for consistency. For that purpose, the absolute mean distance from all registered landmarks to the center of the location cloud was calculated for each dataset. ResultsThe smallest spread in locations was measured for the so-called Epitympanic Notch, with 4.3 mm on average (SD 1.7). However, recognizing this landmark in the segmented images appeared to be relatively difficult. The landmark with the second smallest spread in locations (4.4 mm (SD 2.2)) and an easier recognition in the segmented image was the most superior point of the external auditory meatus. The most inferior point appeared to be the least reliable of all five landmarks. ConclusionBased on the present study, a consistently reliable landmark in the External Auditory Meatus to replace point Porion could not be identified. The hypothesis that any landmark could suffice for superimposing CBCT scans was not confirmed.

Sex determination through maxillary dental arch and skeletal base measurements using machine learning

BackgroundCranial, facial, nasal, and maxillary widths have been shown to be significantly affected by the individual’s sex. The present study aims to use measurements of dental arch and maxillary skeletal base to determine sex, employing supervised machine learning.Materials and methodsMaxillary and mandibular tomographic examinations from 100 patients were analyzed to investigate the inter-premolar width, inter-molar width, maxillary width, inter-pterygoid width, nasal cavity width, nostril width, and maxillary length, obtained through Cone Beam Computed Tomography scans. The following machine learning algorithms were used to build the predictive models: Logistic Regression, Gradient Boosting Classifier, K-Nearest Neighbors (KNN), Support Vector Machine (SVM), Multi-Layer Perceptron Classifier (MLP), Decision Tree, and Random Forest Classifier. A 10-fold cross-validation approach was adopted to validate each model. Metrics such as area under the curve (AUC), accuracy, recall, precision, and F1 Score were calculated for each model, and Receiver Operating Characteristic (ROC) curves were constructed.ResultsUnivariate analysis showed statistical significance (p < 0.10) for all skeletal and dental variables. Nostril width showed greater importance in two models, while Inter-molar width stood out among dental measurements. The models achieved accuracy values ranging from 0.75 to 0.85 on the test data. Logistic Regression, Random Forest, Decision Tree, and SVM models had the highest AUC values, with SVM showing the smallest disparity between cross-validation and test data for accuracy metrics.ConclusionTransverse dental arch and maxillary skeletal base measurements exhibited strong predictive capability, achieving high accuracy with machine learning methods. Among the evaluated models, the SVM algorithm exhibited the best performance. This indicates potential usefulness in forensic sex determination.

Comprehensive sinus contour classification and its characteristics from radiographic examination: a cross-sectional study

ObjectiveThe aim of this study was to propose a comprehensive maxillary sinus (MS) contour classification system based on the evaluation of anatomical characteristics from cone beam computed tomography (CBCT) examination and investigate the relationship between sinus contours and sinus floor elevation (SFE).MethodsA total of 283 CBCT scans from patients who had single tooth loss in the posterior maxilla and underwent SFE were analyzed. The MS was classified at each tooth position. For buccal-palatal evaluation, the classification from Type A to E was narrow-taper, taper, ovoid, square, and irregular, respectively. For mesial-distal evaluation, the classification from Type 1 to 4 was flat, slope, concave, and septa, respectively. The major anatomical parameters evaluated were (1) residual bone height (RBH), (2) sinus width (SW), (3) maxillary sinus angle (MSA), (4) buccal dip angle (BDA), (5) palatonasal recess (PNR), and (6) sinus depth.ResultsEleven groups of MS contour were classified after detailed calculation. Differences in the RBH, MSA, BDA, and SW among different groups were statistically significant. The narrow-taper and slope MS (A2) group had the highest RBH (8.66 ± 0.77 mm), largest BDA (79.9° ± 3.18°), smallest MSA (19.8° ± 2.01°), and narrowest SW (6.30 ± 1.23 mm). The lowest RBH was in the square and concave sinus (D3) group (5.11 ± 2.70 mm). The ovoid and concave sinus (C3) group had the smallest BDA (50.64 ± 8.73 mm) and largest MSA (74.11° ± 11.52°). The square and flat MS (D1) group had the widest SW (19.13 ± 3.69 mm). A strongly significant positive correlation was observed between the SW and MSA (r = 0.67) and a strongly negative correlation between the SW and BDA (r = − 0.65). The prevalence of PNR (mean angle: 104.06° ± 16.83°, mean height: 14.72 ± 11.78 mm) was 38% and frequently observed in the ovoid and slope MS (C2) group.ConclusionDespite certain characteristics at different tooth sites, the same tooth position was categorized differently using different classification systems, indicating large anatomical variations in the MS. The classification system proposed herein allows for classification based on general characteristics at a single tooth site, aiming to help surgeons in improving presurgical evaluation.

Incidental Findings Following Dental Implant Procedures in the Mandible: A New Post-Processing CBCT Software Analysis.

Background/Objectives: The aim of this study was to evaluate incidental findings in the mandible after the placement of dental implants using a new cone-beam computed tomography (CBCT) software. Methods: The initial sample consisted of 2872 CBCT scans of patients of both sexes. The parameters evaluated in this study were the location of the implants in the mandible, implant length, anatomical relationship of the implant with the mandibular canal, presence or absence of damage to the adjacent teeth, presence or absence of implant fractures, and presence or absence of bone support. Fisher's exact test was performed to compare the variables. The significance level was set at p = 0.05. Results: Out of 2872 CBCT scans, 214 images of patients with an average age of 44.5 years were included. The most frequent location of the implants was the posterior region (93.5%), with 54% of the implants having a length between 9 and 14 mm. It was found that 92% of the implants were positioned above the mandibular canal. Damage to adjacent teeth was observed, with no correlation with the implant positioning (p = 1.000). In 100% of cases of implants in the anterior region, there was bone support. Fracture was observed in 1.7% of implants with a length between 9 and 14 mm. Conclusions: The installation of implants in the mandible occurs more frequently in the posterior region, with a high presence of bone support and a low incidence of damage to adjacent teeth, anatomical structures, and fractures.

Novel 3-dimensional classification of cervical abrasion using CBCT: A comprehensive analysis

IntroductionTooth cervical abrasion (CA) is a prevalent non-carious cervical lesion that poses challenges for accurate diagnosis from periapical radiographs due to difficulties in assessing the lesion's extent, associated bone loss, and pulpal involvement. The presence of overlying bone structures on the palatal side when lesions are located on the buccal side, or vice versa, further complicates radiographic interpretation. So it is important to define the lesions in all three dimensions. ObjectiveTo provide a three-dimensional descriptive classification for cervical abrasion lesions using Cone Beam Computed Tomography (CBCT). MethodA total of 50 patients with cervical abrasion were selected for the study. From these patients, teeth (n = 10) from each of the four different quadrants were chosen. A CBCT scan with a 6 × 6 cm field of view (FOV) was performed, and the DICOM files of the cervical lesions were transferred to 3-D imaging software. The CBCT images of the cervical abrasion lesions were assessed at the level of the deepest point of the lesion along the long axis of the tooth in both axial and sagittal planes. The height (A), buccolingual dimension (B), circumferential spread (C), and remaining dentine thickness (D) were evaluated and classified using new scoring criteria for each dimension. The reliability and reproducibility of the classification were assessed to ensure its clinical applicability. ConclusionCBCT can be utilized to classify tooth cervical abrasion in endodontics, enhancing diagnosis, analysis, and treatment outcomes. This three-dimensional view facilitates easier communication among clinicians, allows for tailored treatment approaches, and opens new avenues for research.

Cone-Beam Computed Tomography (CBCT) Analysis of Mandibular Condyles' Diameters in Patient with Juvenile Idiopathic Arthritis and Temporomandibular Joint Affection: A Cross-Sectional Investigation.

Objectives: The aim of this study was to evaluate through analysis using CBCT the transverse and axial diameters of the mandibular condyles in subjects affected by juvenile idiopathic arthritis (JIA) and compare them with those of healthy subjects. Methods: The study was conducted on CBCT scans from the digital archive of the Department of Biomedical Surgical and Dental Sciences, University of Milan, including patients with JIA and using healthy subjects as controls. Inclusion criteria: aged between 7 and 25 years old at the time of the CBCT examination; Caucasian ethnicity; diagnosis of JIA according to the International League of Associations for Rheumatology (ILAR) criteria documented in patients' records; TMJ involvement; good quality CBCTs covering our region of interest (ROI), from the glabella to the mandibular inferior border; no previous orthodontic/orthopedic treatment; no history of craniofacial trauma or congenital birth defects involving the craniofacial area. Each CBCT scan underwent examination using 3Diagnosys® software. Since data were normally distributed, parametric tests were used for analysis. The sample was divided into three groups: (1) bilateral JIA subjects, (2) unilateral JIA subjects, and (3) healthy controls. Results: We found a statistically significant reduction (p < 0.0001) in the transverse diameter (TR-Diam) of the affected condyles by an average of 1.7 mm, while the axial diameter (AX-Diam) again showed a slight reduction, on average by 0.1 mm, with a non-statistically significant value. Another comparison was made between the unaffected condyles of patients with unilateral JIA and the healthy condyles of the control group. The unilateral unaffected condyles were found to be slightly smaller than those of healthy patients, but without statistically significant differences. We found that in both JIA males and females, the condylar growth tends to stop earlier than the healthy ones. Conclusions: The transverse diameter was found to be more affected than the axial one, causing typical bone resorption and condylar shape. Moreover, we showed that the pathology, in the case of unilateral JIA, does not compromise only the affected condyles; the corresponding condyle that seems to be healthy is actually partially compromised. In addition, we observed that the growth of affected condyles of JIA subjects tends to stop earlier than the condyles of the healthy controls.

Anatomical Variations of the Jugular Bulb: A Critical and Comprehensive Review.

Background and Objectives: The jugular bulb (JB) is the uppermost part of the internal jugular vein receiving the sigmoid sinus. The aim of the present research is to aid the comprehension of the JB, its abnormalities, and surrounding structures for improving both academic and surgical awareness. Materials and Methods: Various studies on this topic were critically reviewed. Cone-beam CT scans and CT and MR angiograms were used to demonstrate each type of the discussed variations. Results: Variations in the JB anatomy were thoroughly documented: high JB, dehiscent JB, hypoplasia and hyperplasia, and diverticula of the JB, as they have significant clinical implications, particularly in the context of otological and neuro-otological surgery, skull base pathology, and diagnostic imaging. Definitions and critical arguments were also specified to clarify existing literature. Additionally, we present a case report illustrating a high and dehiscent JB, an anatomical variation of clinical interest due to its potential for misdiagnosis as a glomus tumor. Another case describes a dehiscent JB with a hypotympanic air cell protruding into it, further highlighting the variability of this condition. Conclusions: It is necessary to proceed with caution when observing abnormal morphological characteristics of the JB. Preoperative assessment of each case is essential for optimal outcomes.

A skeletal Class III young adult with severe maxillary transverse deficiency treated with maxillary skeletal expander.

This case report describes correction of maxillary constriction using a maxillary skeletal expander (MSE) in a 15-year-old female with a skeletal Class III pattern and asymmetry. The maxillary expansion device with four mini-implants was used to correct the constricted maxilla, bilateral crossbite of the posterior teeth, and crowding of the dentition. Comparison of cone-beam computed tomography scans before and after treatment showed that the majority of maxillary expansion was orthopedic, with minimal alveolar bone bending and tooth tipping. Fixed appliances were used to correct the crowding and malocclusion. Stable and satisfactory maxillary expansion was obtained by using MSE non-urgically.

Evaluation of Digitally Customized Titanium Mesh-Guided Alveolar Ridge Augmentation

Background: Different bone augmentation methods are used to increase the alveolar crest following the loss of one or more teeth. Guided bone regeneration is an alternative to increasing the amount of hard tissue for subsequent implant placement in the best three-dimensional position. Objectives: To evaluate the effects of bone regeneration utilizing a customized titanium mesh scaffold covered with a combination of autologous bone transplant and xenograft for the restoration of complex jaw deformities. Methods: This prospective clinical interventional study included ten patients receiving ridge augmentation of the partly edentulous mandible or maxilla after the alveolar ridge had resorbed (horizontally). A pre-surgical cone beam computed tomography (CBCT) scan was performed to assess the pre-surgical ridge size and fabricate the customized titanium mesh (CTM). A CBCT scan will be performed immediately after surgery, followed by a second CBCT scan 6 months later to measure width and volumetric analysis. Results: Both arches had a rise in volumetric gain from preoperative to postoperative, with no significant difference. Females gained more than males, although the difference was not statistically significant (males lost density after surgery). They also discovered that age, gender, and arch were not substantially associated with mesh size exposure. Conclusions: Using tailored titanium mesh scaffolds in conjunction with autogenous bone and xenografts for alveolar ridge augmentation can efficiently increase bone mass, but future research must address many limitations.

Deep Learning-Based Workflow for Bone Segmentation and 3D Modeling in Cone-Beam CT Orthopedic Imaging

In this study, a deep learning-based workflow designed for the segmentation and 3D modeling of bones in cone beam computed tomography (CBCT) orthopedic imaging is presented. This workflow uses a convolutional neural network (CNN), specifically a U-Net architecture, to perform precise bone segmentation even in challenging anatomical regions such as limbs, joints, and extremities, where bone boundaries are less distinct and densities are highly variable. The effectiveness of the proposed workflow was evaluated by comparing the generated 3D models against those obtained through other segmentation methods, including SegNet, binary thresholding, and graph cut algorithms. The accuracy of these models was quantitatively assessed using the Jaccard index, the Dice coefficient, and the Hausdorff distance metrics. The results indicate that the U-Net-based segmentation consistently outperforms other techniques, producing more accurate and reliable 3D bone models. The user interface developed for this workflow facilitates intuitive visualization and manipulation of the 3D models, enhancing the usability and effectiveness of the segmentation process in both clinical and research settings. The findings suggest that the proposed deep learning-based workflow holds significant potential for improving the accuracy of bone segmentation and the quality of 3D models derived from CBCT scans, contributing to better diagnostic and pre-surgical planning outcomes in orthopedic practice.

Shaping ability of HyFlex EDM and ProTaper Gold files with or without using glide path files: An in vitro study

Abstract Introduction: The necessity of using a glide path before the canal preparation is inconclusive. Therefore, this study aimed to assess the shaping ability of two rotary systems in the maxillary first molars’ first mesiobuccal canal (MB1), with or without employing the glide path files. Materials and Methods: The MB1 canals of 100 extracted molars were randomly prepared using either HyFlex EDM (HEDM) or ProTaper Gold (PTG) systems (n = 50 each). Half of the samples in each group were prepared using ProGlider (PG) or HyFlex EDM Glide (HEG). The cone-beam computed tomography scanning was conducted before and after the instrumentation. The canal transportation, centering ability, and remaining dentin thickness were evaluated and compared between the groups using the independent sample t-test and Mann–Whitney U-test (α =0.05). Results: Using HEDM compared to PTG led to greater centering ability at the sub-furcation area (P &lt; 0.05), lower canal transportation at 2 mm below furcation (P = 0.025), and more dentin removed at the middle area (P = 0.011). The systems’ centering ability and canal transportation were comparable when path files were used. Utilizing HEG with HEDM decreased dentin removal at 2 mm below furcation (P = 0.045) and middle area (P = 0.008). Canal preparation with HEDM-HEG caused less dentin removal at 2 mm below furcation than PTG-PG (P = 0.007). Conclusions: The HEDM system outperformed PTG regarding centering ability in the sub-furcation areas and canal transportation 2 mm below the furcation. However, HEDM showed more dentin removal in the middle region than PTG, which was resolved when HEG was used. Therefore, using PathFile with the HEDM system might be suggested.

Maxillary sinus membrane perforation rate utilizing osseodensification-mediated transcrestal sinus floor elevation: A multicenter clinical study.

This multicenter cross-sectional clinical study aimed to evaluate the membrane perforation rate during transcrestal sinus floor elevation (TSFE) using osseodensification (OD) burs and assess risk factors associated with the procedure. This study was conducted in six centers, following ethical standards and approved by local committees. It included patients over 18 years old missing maxillary posterior teeth with crestal residual bone height (RBH) ≥2 and ≤6 mm. Preoperative evaluations were done, including CBCT scans, to assess bone dimensions and sinus health. All centers and surgeons followed a standardized surgical protocol for TSFE using OD burs. Surgical complications, particularly sinus membrane perforations, were recorded and analyzed. Factors such as implant site, premolars or molars, as well as, healed or fresh socket, along with initial RBH were evaluated for their impact on membrane perforation rate. Descriptive statistics, χ2, and logistic regression analysis were used to analyze the data. A total of 621 subjects with an average age of 57.9 years were included. Sinus lifting was performed at 670 sites, with 621 implants placed in the maxilla. The majority of sinus lifts were done in the molar region (76.87%) and in healed bone sites (74.33%). The average RBH was 5.1 mm (ranging from 2 to 7 mm). Sinus membrane perforation occurred in 49 cases (7.31%). RBH ≤3 mm posed a risk factor for sinus membrane perforations followed by RBH >3 and ≤5 mm. Tooth region and implant site were not associated as risk factors for sinus membrane perforation. OD drilling used for TSFE resulted in low membrane perforation rate. Challenging scenarios of severe posterior maxillary atrophy presented as risk factors for increased perforation rate.

Anatomical Position of the Mentonian Foramen in Relation to the Alveolar Ridge and Mandibular Base using Cone Beam Computed Tomography in Dentate Patients

Introduction: The mentonian foramen is an important structure of the anterior part of the mandible, referent in surgical procedures of the mandible, mainly of the interforaminal area. Therefore, for a more precise analysis of this anatomical structure we use Cone Beam CT scans, since it provides us with a three-dimensional image of higher quality of the maxillofacial massif as it does not present overlapping images, geometric distortion and false negatives that could increase the risk of iatrogenic lesions. Objective: To determine the distance of the mentonian foramen in relation to the alveolar ridge and the mandibular base by means of Cone Beam Computed Tomography of dentate patients. Methodology: The study was descriptive, cross-sectional and retrospective; 109 Cone Beam Computed Tomography scans of dentate patients were evaluated from March to October 2020, taken from the Maxillofacial Diagnostic Institute (IDM) Lima, Peru; between 18 and 50 years old, distributed in three age groups: 18 to 28 years old, 29 to 39 years old and 40 to 50 years old. The distances from the upper edge of the mentonian foramen to the alveolar ridge and from the lower edge of the mentonian foramen to the mandibular base were analyzed, taking into account sex and age group. For the statistical analysis, SPSS Statistics version 26.0 was used and the T student test for related tests was applied to evaluate the differences between the right and left sides, T student for independent tests to analyze the measures with the male and female sexes and ANOVA of one factor for the analysis with the age groups. All tests were performed at a significance level of 5%. Results: The mentonian foramen is closer to the mandibular base than to the alveolar ridge, whose means are 13.81mm and 14mm, respectively. The average distance was shorter in the 40 to 50 years age group and the female sex presented shorter distances. Conclusion: The mentonian foramen is 13.81mm above the mandibular base, the greatest distances were found in the male sex and the shortest distances in the 40 to 50 years age group.