Effective dose of dental CBCT-a meta analysis of published data and additional data for nine CBCT units

Does the Outcome of Graft Materials at Dental Implant Sites Differ Between Patients With Normal and Compromised Bone Health?

The objective of this paper was to assess the outcome of bone graft material at alveolar bone augmentation sites combined with dental implants in postmenopausal women with compromised bone health by evaluating cone beam computerized tomography (CBCT) scans at multiple time points.CBCT scans were analyzed on 55 postmenopausal women with compromised bone health status to determine the fate of alveolar bone augmentation. CBCT scans were taken immediately after surgery and 9 and 24 months postoperatively. The patient's medication regimens and durations were recorded, and the pixel intensity value (PIV) was measured and standardized using scoring criteria and visual assessment. Statistical analyses included 2-sample t tests for continuous variables and Fisher's exact tests for categorical variables.Among the normal patients, 73% received a grade 2 visual score, and 27% received a grade 1 visual score. After 24 months, 45% of patients received a grade 2 score, and 27% received a grade 3 score. In the osteoporotic group receiving medication, 77% of participants received a grade 1 visual score at the 9-month postoperative evaluation, while 23% received a grade 2 score. At the 24-month assessment, 55% of patients received a grade 1 score, 41% received a grade 2 score, and only 5% received a grade 3 score. Notably, although the graft material did not remodel into native bone, it was a scaffold for implants in controlled osteoporotic patients. The study's results show that the pixel intensity values of particulate graft materials are similar across the three different time points, suggesting that the graft material's pixel intensity value remains constant in postmenopausal women with osteoporosis. The study's limitations include a small sample size and a restricted 24-month follow-up period. This limited time frame may need to capture long-term changes or variations in graft materials adequately. Future research should include a larger sample size and have a longer follow-up duration to provide a more comprehensive understanding of the change in graft materials between patients with normal and compromised bone health.

Accuracy of conventional versus cone-beam CT-synthesised lateral cephalograms for cephalometric analysis: A systematic review

OBJECTIVE

To assess the accuracy of cone-beam computed tomography (CBCT)-synthesised lateral cephalograms (CSLCs) compared with conventional lateral cephalograms for cephalometric analysis in human participants and skull models.

METHODS

The authors performed a search of PubMed, Scopus, Google Scholar and Embase databases on 4 October 2021. Included studies met the following criteria: published in English; compared conventional lateral cephalograms and CSLCs; assessed hard- and soft-tissue landmarks; and were performed on human or skull models. Data extraction from eligible studies was performed by two independent reviewers. The quality of evidence was assessed using the Joanna Briggs Institute (JBI) Critical Appraisal Checklist tool - diagnostic accuracy studies.

RESULTS

A total of 20 eligible articles were included in this systematic review. Of these 20 studies, 17 presented with a low risk of bias, while three were found to have a moderate risk of bias. Hard- and soft-tissue analyses were evaluated for each imaging modality. The findings reveal that CSLCs are accurate and comparable to conventional lateral cephalograms for cephalometric analysis and demonstrate good inter-observer reliability. Four studies reported a higher accuracy with CSLCs.

CONCLUSION

Overall, the diagnostic accuracy and reproducibility of CSLCs were comparable to conventional lateral cephalograms in cephalometric analysis. It is justified that patients who have an existing CBCT scan do not need an additional lateral cephalogram, minimising unnecessary radiation exposure, expenses and time for the patient. Larger voxel sizes and low-dose CBCT protocols can be considered to minimise radiation exposure.

REGISTRATION

This study was registered with PROSPERO (CRD42021282019).

Feasibility of 3 Tesla MRI for the assessment of mid-palatal suture maturation: a retrospective pilot study

The maxilla occupies a key position in dentofacial orthopaedics, since its transversal development can be directly influenced by orthodontic therapy. The maturation stages of the mid-palatal suture, which are obtained from cone-beam computed tomography images (CBCT), present an addition to clinical decision-making in transversal discrepancies of the upper jaw. In an endeavour to reduce ionizing radiation in adolescents and young adults, who are particularly susceptible to long term stochastic irradiation effects, we investigated the feasibility of 3 Tesla (3T) MRI in detecting the maturation stages of the mid-palatal suture. A collective of 30 patients aged 24-93 years with routine neck MRI at 3T, underwent an additional three-dimensional isotropic T1 weighted study sequence of the midface. Image evaluation was performed on axial, multi-planar formatted reconstructions of the dataset aligned to the midline axis of the palate, and curved reconstructions aligned to the concavity of the palate. Inverted images helped to achieve an image impression similar to the well-known CBCT appearance. All datasets were reviewed by three readers and mid-palatal maturation was scored twice according to Angelieri et al. Intra- and inter-rater agreement were evaluated to measure the robustness of the images for clinical evaluation. 3T MRI deemed reliable for the assessment of mid-palatal suture maturation and hence for the appraisal of the hard palate and its adjacent sutures. The data of this pilot study display the feasibility of non-ionizing cross-sectional MRI for the determination of sutural maturation stages. These findings underline the potential of MRI for orthodontic treatment planning, further contributing to the avoidance of unnecessary radiation doses.

Diagnostic yield of dental radiography and digital tomosynthesis for the identification of anatomic structures in cats

Introduction

Digital tomosynthesis (DT) has emerged as a potential imaging modality for evaluating anatomic structures in veterinary medicine. This study aims to validate the diagnostic yield of DT in identifying predefined anatomic structures in feline cadaver heads, comparing it with conventional intraoral dental radiography (DR).

Methods

A total of 16 feline cadaver heads were utilized to evaluate 19 predefined clinically relevant anatomic structures using both DR and DT. A semi-quantitative scoring system was employed to characterize the ability of each imaging method to identify these structures.

Results

DT demonstrated a significantly higher diagnostic yield compared to DR for all evaluated anatomic structures. Orthogonal DT imaging identified 13 additional anatomic landmarks compared to a standard 10-view feline set obtained via DR. Moreover, DT achieved statistically significant higher scores for each of these landmarks, indicating improved visualization over DR.

Discussion

These findings validate the utility of DT technology in reliably identifying clinically relevant anatomic structures in the cat skull. This validation serves as a foundation for further exploration of DT imaging in detecting dentoalveolar and other maxillofacial bony lesions and pathologies in cats.

AAPM Task Group Report 261: Comprehensive quality control methodology and management of dental and maxillofacial cone beam computed tomography (CBCT) systems

Cone-beam computed tomography (CBCT) systems specifically designed and manufactured for dental, maxillofacial imaging (MFI) and otolaryngology (OLR) applications have been commercially available in the United States since 2001 and have been in widespread clinical use since. Until recently, there has been a lack of professional guidance available for medical physicists about how to assess and evaluate the performance of these systems and about the establishment and management of quality control (QC) programs. The owners and users of dental CBCT systems may have only a rudimentary understanding of this technology, including how it differs from conventional multidetector CT (MDCT) in terms of acceptable radiation safety practices. Dental CBCT systems differ from MDCT in several ways and these differences are described. This report provides guidance to medical physicists and serves as a basis for stakeholders to make informed decisions regarding how to manage and develop a QC program for dental CBCT systems. It is important that a medical physicist with experience in dental CBCT serves as a resource on this technology and the associated radiation protection best practices. The medical physicist should be involved at the pre-installation stage to ensure that a CBCT room configuration allows for a safe and efficient workflow and that structural shielding, if needed, is designed into the architectural plans. Acceptance testing of new installations should include assessment of mechanical alignment of patient positioning lasers and x-ray beam collimation and benchmarking of essential image quality performance parameters such as image uniformity, noise, contrast-to-noise ratio (CNR), spatial resolution, and artifacts. Several approaches for quantifying radiation output from these systems are described, including simply measuring the incident air-kerma (Kair) at the entrance surface of the image receptor. These measurements are to be repeated at least annually as part of routine QC by the medical physicist. QC programs for dental CBCT, at least in the United States, are often driven by state regulations, accreditation program requirements, or manufacturer recommendations.

Machine learning assisted 5-part tooth segmentation method for CBCT-based dental age estimation in adults

BACKGROUND

The utilization of segmentation method using volumetric data in adults dental age estimation (DAE) from cone-beam computed tomography (CBCT) was further expanded by using current 5-Part Tooth Segmentation (SG) method. Additionally, supervised machine learning modelling -namely support vector regression (SVR) with linear and polynomial kernel, and regression tree - was tested and compared with the multiple linear regression model.

MATERIAL AND METHODS

CBCT scans from 99 patients aged between 20 to 59.99 was collected. Eighty eligible teeth including maxillary canine, lateral incisor, and central incisor were used in this study. Enamel to dentine volume ratio, pulp to dentine volume ratio, lower tooth volume ratio, and sex was utilized as independent variable to predict chronological age.

RESULTS

No multicollinearity was detected in the models. The best performing model comes from maxillary lateral incisor using SVR with polynomial kernel ( = 0.73). The lowest error rate achieved by the model was given also by maxillary lateral incisor, with 4.86 years of mean average error and 6.05 years of root means squared error. However, demands a complex approach to segment the enamel volume in the crown section and a lengthier labour time of 45 minutes per tooth.

Pre-eruptive intramural resorption in unerupted teeth: a cone-beam computed tomography evaluation of prevalence and related factors

OBJECTIVE

Pre-eruptive intramural resorption (PEIR) is defined as an abnormal, well-circumscribed radiolucency within the coronal dentin of the tooth, which is often overlooked in plain radiographs. This study aimed to investigate the prevalence of PEIR and its related factors using cone-beam computed tomography (CBCT).

METHODS

CBCT images of 590 unerupted teeth were evaluated for the presence of PEIR, location of PEIR, number of lesions in the affected tooth, PEIR score, tooth angulation, tooth position, and pericoronal space. Binary logistic tests were used to analyze the association between the characteristics of PEIR and the patient's demographic data and related factors.

RESULTS

The tooth prevalence of PEIR was 13.6% among unerupted teeth. However, it was noteworthy that 19.2% of the unerupted teeth with PEIR were planned to be kept. PEIR was significantly associated with transverse (p = 0.020), inverted-angulated (p = 0.035), and centrally-positioned teeth (p = 0.043). The severity of PEIR was more pronounced in teeth with distal (p = 0.019), lingual (p = 0.023), or inverted-angulated (p = 0.040) positions, and in the absence of pericoronal space (p = 0.036).

CONCLUSION

PEIR should be suspected in transverse, inverted-angulated, centrally positioned unerupted teeth, particularly in molars, with no pericoronal space. Further monitoring through CBCT is recommended in such cases.

CLINICAL RELEVANCE

The management of unerupted teeth does not always involve surgical removal. Instead, they could be utilized for artificial eruption or tooth transplantation. The present study emphasizes the significance of early detection of PEIR. Clinical recommendations for screening PEIR in unerupted teeth are also proposed, which can be applied to routine plain radiographs.

Impact of acquisition volume on cone beam computed tomography imaging of marginal bone: an ex vivo study

OBJECTIVE

The current study explores whether there is a clinically relevant distinction in the measurement of marginal bone loss when comparing high-dose (HD) versus low-dose (LD) cone beam computed tomography (CBCT) protocols in small and large acquisition volumes.  Material and Methods: CBCTs of four human cadaveric preparates were taken in HD and LD mode in two different fields of view 8 × 8 cm2 (LV) and 5 × 5 cm2 (SV). In total, 43 sites of 15 teeth were randomly chosen, and marginal bone loss was measured twice in all protocols at 43 sites of 15 teeth by one calibrated investigator. Bland-Altman plots and Lin's concordance correlation coefficient (CCC) were calculated to assess the extent of agreement of the measurements. Additionally, the rater scored the certainty in each of the measurements.

RESULTS

For HD-CBCT CCC of measurements obtained using SV versus LV was 0.991. CCC of measurements obtained using SV versus LV of LD-CBCT was 0.963. Both CCC values indicated excellent agreement between the two volumes in both protocols.  CCC also indicated high intramodality correlation between HD-CBCT and LD-CBCT independent of the acquisition volume (0.963 - 0.992). Bland-Altman plots also indicated no substantial differences. Results of certainty scoring showed significant differences (p = 0.004 (LV), p < 0.001(SV)) between the LD and HD-CBCT.

CONCLUSIONS

Accuracy of measurements of bone loss shows no clinical noticeable effects depending on the CBCT volume in this ex vivo study. There appears to be no relevant advantage of SV over LV, neither in HD-CBCT nor in LD-CBCT and additionally no relevant advantage of HD versus LD in visualizing marginal bone loss.

Long-Term Volumetric Stability of Maxillary Sinus Floor Augmentation Using a Xenograft Bone Substitute and Its Combination with Autologous Bone: A 6+ Year Retrospective Follow-Up Study Using Cone Beam Computed Tomography

Deproteinised bovine bone (DBB) is widely used as bone substitute in maxillary sinus floor augmentation (MSFA) surgery. No previous studies have shown the long-term volumetric changes in the augmented bone when using DBB. The selected patients had MFSA performed using a lateral window technique and a xenograft, alone or in combination with the patient's autologous bone from the mandible. Cone beam computed tomography (CBCT) images were used to compare the volumetric changes in the augmented bone for patients over a period of 6 or more years. No significant bone reduction was seen in the augmented bone region when comparing MSFA after 7 months and 6 or more years after dental implantation.

Incidental findings in cone beam computed tomography (CBCT) scans for implant treatment planning: a retrospective study of 404 CBCT scans

OBJECTIVES

To investigate the prevalence of incidental findings and need for further dental treatment and analyse the influence of size of field-of-view (FOV) and age in cone beam computed tomography (CBCT) for pre-implant planning.

METHODS

404 CBCT scans were examined retrospectively for incidental findings and need for further dental treatment. Incidental finding-frequencies and need for further treatment were assessed for different age (< 40 years, 40-60 years, > 60 years) and FOV groups (small, medium, large). Intraexaminer and interexaminer agreements were evaluated.

RESULTS

In 82% of the scans at least one incidental finding was found, with a total of 766 overall. More incidental findings were found in scans with large FOV (98% vs. 72%, OR = 22.39 large vs. small FOV, p < 0.0001) and in scans of patients > 60 years (OR = 5.37 patient's age > 60 years vs. < 40 years, p = 0.0003). Further dental treatment due to incidental findings was needed in 31%. Scans with large FOV were more likely to entail further treatment (OR = 3.55 large vs. small FOV, p < 0.0001). Partial edentulism and large FOV were identified as risk factors for further treatment (p = 0.0003 and p < 0.0001). Further referral of the patient based on incidental findings was judged as indicated in 5%. Intra- and inter-examiner agreements were excellent (kappa = 0.944/0.805).

CONCLUSIONS

A considerable number of incidental findings with need for further dental treatment was found in partially edentulous patients and in patients > 60 years. In pre-implant planning of elderly patients, the selection of large FOV CBCT scans, including dentoalveolar regions not X-rayed recently, help to detect therapeutically relevant incidental findings.

Optimizing radiation safety in dentistry: Clinical recommendations and regulatory considerations

BACKGROUND

The value of dental radiographs to oral health care decision making must be balanced with radiation safety to minimize patient exposure and occupational risk of oral health care providers. This review summarizes recommendations and regulatory guidance regarding dental radiography and cone-beam computed tomography. An expert panel presents recommendations on radiation safety, appropriate imaging practices, and reducing radiation exposure.

TYPES OF STUDIES REVIEWED

A systematic search run in Ovid MEDLINE, Embase, and Cochrane Database of Systematic Reviews identified relevant topical systematic reviews, organizational guidelines, and regulatory reviews published in the peer-reviewed literature since 2010. A supplemental search of the gray literature (eg, technical reports, standards, and regulations) identified topical nonindexed publications. Inclusion criteria required relevance to primary oral health care (ie, general or pediatric dentistry).

RESULTS

A total of 95 articles, guidance documents, and regulations met the inclusion criteria. Resources were characterized as applicable to all modalities, operator and occupational protection, dose reduction and optimization, and quality assurance and control.

PRACTICAL IMPLICATIONS

Understanding factors affecting imaging safety and applying fundamental principles of radiation protection consistent with federal, state, and local requirements are essential for limiting patient ionizing radiation exposure, in conjunction with implementing optimal imaging procedures to support prudent use of dental radiographs and cone-beam computed tomographic imaging. The regulatory guidance and best practice recommendations summarized in this article should be followed by dentists and other oral health care providers.

Clinical considerations of emergent oral manifestations during pregnancy

Pregnancy is a special period for developing and treating oral diseases. Oral emergencies during pregnancy need to be handled appropriately. Changes in the physiological environments and personal habits of pregnant women increase susceptibility to some oral diseases. However, clinical treatment strategies are limited due to the need to ensure the safety of pregnant women and fetuses. Pregnant women should obtain oral health knowledge and enhance their awareness. Dentists should adhere to the principle of "prevention before pregnancy, controlling symptoms during pregnancy, and treating diseases after pregnancy" for different pregnancy periods. They should also formulate appropriate treatment plans to control emergencies, prevent disease progression, and avoid harmful effects on pregnant women by using the safest, simplest, and most effective strategies that avoid adverse effects on fetuses. Pregnant women and dentists should combine prevention and treatment while collaborating in maintaining oral health during pregnancy. This article focuses on the principles of treatment during pregnancy, and the treatment timing, clinical management, and treatment strategies of different diseases causing oral emergencies during pregnancy are reviewed.

A carbon nanotube x-ray source array designed for a new multisource cone beam computed tomography scanner

Cone beam computed tomography (CBCT) is known to suffer from strong scatter and cone beam artifacts. The purpose of this study is to develop and characterize a rapidly scanning carbon nanotube (CNT) field emission x-ray source array to enable a multisource CBCT (ms-CBCT) image acquisition scheme which has been demonstrated to overcome these limitations. A CNT x-ray source array with eight evenly spaced focal spots was designed and fabricated for a medium field of view ms-CBCT for maxillofacial imaging. An external multisource collimator was used to confine the radiation from each focal spot to a narrow cone angle. For ms-CBCT imaging, the array was placed in the axial direction and rapidly scanned while rotating continuously around the object with a flat panel detector. The x-ray beam profile, temporal and spatial resolutions, energy and dose rate were characterized and evaluated for maxillofacial imaging. The CNT x-ray source array achieved a consistent focal spot size of 1.10 ± 0.04 mm × 0.84 ± 0.03 mm and individual beam cone angle of 2.4°±0.08 after collimation. The x-ray beams were rapidly switched with a rising and damping times of 0.21 ms and 0.19 ms, respectively. Under the designed operating condition of 110 kVp and 15 mA, a dose rate of 8245μGy s-1was obtained at the detector surface with the inherent Al filtration and 2312μGy s-1with an additional 0.3 mm Cu filter. There was negligible change of the x-ray dose rate over many operating cycles. A ms-CBCT scan of an adult head phantom was completed in 14.4 s total exposure time for the imaging dose in the range of that of a clinical CBCT scanner. A spatially distributed CNT x-ray source array was designed and fabricated. It has enabled a new multisource CBCT to overcome some of the main inherent limitations of the conventional CBCT.

A systematic review and meta-analysis of the genotoxic and cytotoxic effects on oral epithelium induced by cone beam computed tomography

OBJECTIVE

To evaluate the occurrence of genotoxic and cytotoxic effects in oral epithelium after exposure of patients to cone beam computed tomography (CBCT).

METHODS

A systematic review (SR) was conducted following the PECO (Population, Exposure, Comparison, Outcome) criteria. The study was registered in the International Prospective Register of Systematic Reviews (PROSPERO). A search was performed on the PubMed, Scopus, ScienceDirect, and Google Scholar databases. Effect size and heterogeneity of data were evaluated statistically. The Joanna Briggs Institute questionnaire for observational studies was utilized to assess the risk of bias. The GRADE tool was applied for the assessment of the quality of evidence. Begg's funnel plot was used to evaluate publication bias.

RESULTS

In total, 10 full-text articles were included in the SR, with 6 of them in the meta-analysis. The SR showed a significant increase in micronuclei after exposure, with a large effect size of 1.03. For genotoxicity, the tau2 for heterogeneity was 0.96, the chi-squared test for heterogeneity P < .00001, the I2 statistics for random effects was 91%, and the overall effect for Z value was 2.46 (P = .01). The risk of bias was low, the quality of evidence was strong, and publication bias was absent.

CONCLUSION

CBCT can cause genotoxicity in the oral epithelium with a large effect size. The measure of cytotoxicity after CBCT exposure was not possible due to the lack of homogeneity of the included articles.

A simplified low-cost phantom for image quality assessment of dental cone beam computed tomography unit

INTRODUCTION

A standardised testing protocol for evaluation of a wide range of dental cone beam computed tomography (CBCT) performance and image quality (IQ) parameters is still limited and commercially available testing tool is unaffordable by some centres. This study aims to assess the performance of a low-cost fabricated phantom for image quality assessment (IQA) of digital CBCT unit.

METHODS

A customised polymethyl methacrylate (PMMA) cylindrical phantom was developed for performance evaluation of Planmeca ProMax 3D Mid digital dental CBCT unit. The fabricated phantom consists of four different layers for testing specific IQ parameters such as CT number accuracy and uniformity, noise and CT number linearity. The phantom was scanned using common scanning protocols in clinical routine (90.0 kV, 8.0 mA and 13.6 s). In region-of-interest (ROI) analysis, the mean CT numbers (in Hounsfield unit, HU) and noise for water and air were determined and compared with the reference values (0 HU for water and -1000 HU for air). For linearity test, the correlation between the measured HU of different inserts with their density was studied.

RESULTS

The average CT number were -994.1 HU and -2.4 HU, for air and water, respectively and the differences were within the recommended acceptable limit. The linearity test showed a strong positive correlation (R2  = 0.9693) between the measured HU and their densities.

CONCLUSION

The fabricated IQ phantom serves as a simple and affordable testing tool for digital dental CBCT imaging.

A Three-Dimensional Evaluation of Skeletal and Dentoalveolar Changes in Growing Class II Patients after Functional Appliance Therapy: A Retrospective Case-Control Study

Background: The aim was to assess three-dimensionally mandibular and maxillary changes in growing Class II patients treated with removable functional appliances followed by fixed appliances. Methods: Twenty-four Class II patients (age range: 9 to 14, mean: 12.1 ± 1.1 years) treated with removable functional appliances followed by fixed appliances (functional appliance group-FAG) were retrospectively selected and compared to an age-matched control group (CG) treated with fixed appliances only. To be included in the study, pre- and post-treatment CBCT scans had to be available. The CBCTs were used to analyze, in 3D, the changes following treatment and growth. Results: Before treatment, overjet (FAG: 9 mm ± 2.8 (mean ± standard deviation); CG: 4 mm ± 1.7), ANB (FAG: 5.7° ± 2.0; CG: 3.2° ± 1.4), and effective mandibular length (FAG: 113.0 mm ± 4.1; CG: 116.6 mm ± 5.9) were statistically significantly different between the two groups. After treatment, overjet (FAG: -6.8 mm ± 2.8; CG: -1.8 mm ± 1.8) and effective mandibular length (FAG: 6.3 mm ± 2.6; CG: 3.9 mm ± 2.6) statistically significantly changed. There was a significant difference in the treatment effect between the FAG and the CG in overjet, ANB, and effective mandibular length. Conclusions: The results indicate that functional appliances are effective in correcting Class II malocclusions. The growth modification in the FAG resulted in an increase in mandibular length. Yet, the final length of the mandible in the FAG was smaller when compared to the CG.

Diagnostic Accuracy of Cone Beam Computed Tomography and Periapical Radiography for Detecting Apical Root Resorption in Retention Phase of Orthodontic Patients: A Cross-Sectional Study

Objectives: This clinical study aimed to evaluate and compare the diagnostic accuracy of intraoral periapical radiography (PR) and cone beam computed tomography (CBCT) in detecting external apical root resorption (EARR) in orthodontic patients during the retention phase. Methods: The research involved 41 Caucasian patients who had undergone comprehensive orthodontic treatment, with a total of 328 teeth analyzed. The Kappa values for inter- and intra-examiner agreement were high for both PR and CBCT, indicating a robust level of agreement among examiners. The study used a four-point scale for classifying EARR. Results: This study showed comparable accuracy, sensitivity, and specificity between PR and CBCT when using the most stringent criterion of "Definitely present". The data suggested that CBCT outperformed PR when using a less stringent criterion ("Definitely present" or "Probably present"), particularly for maxillary incisors. However, overall diagnostic performance, as measured by the area under the ROC curve, showed only a slight advantage for CBCT over PR. Areas under the ROC curve range between 0.85 and 0.90 for PR and between 0.89 and 0.92 for CBCT. According to DeLong's test, there is no evidence to conclude that the area under the ROC curve is different for PR and CBCT. Conclusions: Both PR and CBCT are accurate diagnostic tools for identifying EARR, with PR being deemed more suitable for routine clinical use due to its cost-effectiveness and lower radiation exposure. The findings emphasize the importance of considering the risk-benefit ratio when deciding on imaging modalities for monitoring EARR in orthodontic patients.

The Application of Cone Beam Computed Tomography (CBCT) on the Diagnosis and Management of Maxillofacial Trauma

The assessment and management of facial trauma in an acute setting is one of the core services provided by oral and maxillofacial units in the United Kingdom. Imaging is a pre-requisite for appropriate diagnosis and treatment planning, with a combination of plain radiographs and medical-grade CT being the mainstay. However, the emergence of cone beam CT in recent years has led to its wider applications, including facial trauma assessment. It can offer multi-planar reformats and three-dimensional reconstruction at a much lower radiation dose and financial cost than conventional CT. The purpose of this review is to appraise its potential indications in all anatomical areas of maxillofacial trauma and provide our experience at a level 1 trauma centre.

The use of digital technologies in peri-implant soft tissue augmentation - A narrative review on planning, measurements, monitoring and aesthetics

OBJECTIVE

To identify the different uses and modalities of digital technologies to diagnose, plan and monitor peri-implant soft tissue conditions and aesthetics.

METHODS

A comprehensive narrative review of pertinent literature was conducted, critically appraising key digital technologies that may assist peri-implant soft tissue augmentation and assessment. An electronic search on four databases including studies published prior to 1st July 2023 was performed and supplemented by a manual search.

RESULTS

Predominantly, tools such as cone beam computed tomography (CBCT), intraoral scanning (iOS), intraoral ultrasonography and digital spectrophotometry were commonly to assess and monitor peri-implant soft tissues. The main clinical and research applications included: (i) initial assessment of mucosal thickness, supra-crestal tissue height and keratinized mucosa width, (ii) evaluation of peri-implant soft tissue health and inflammation, (iii) monitoring profilometric changes and midfacial mucosal margin stability over time and (iv) aesthetic evaluation through colour assessment. While evidence for some digital tools may be limited, the integration of digital technologies into peri-implant soft tissue management holds great promise. These technologies offer improved precision, comfort and speed in assessment, benefiting both patients and clinicians.

CONCLUSION

As digital technologies progress, their full potential in peri-implant soft tissue augmentation and their value will become more evident with ongoing research. Embracing these innovations and their potential benefits is recommended to ensure that during progress in implant dentistry, patient care is not hindered.

Cone-beam computed tomography in endodontics: from the specific technical considerations of acquisition parameters and interpretation to advanced clinical applications

The implementation of imaging methods that enable sensitive and specific observation of anatomical structures has been a constant in the evolution of endodontic therapy. Cone-beam computed tomography (CBCT) enables 3-dimensional (3D) spatial anatomical navigation in the 3 volumetric planes (sagittal, coronal and axial) which translates into great accuracy for the identification of endodontic pathologies/conditions. CBCT interpretation consists of 2 main components: (i) the generation of specific tasks of the image and (ii) the subsequent interpretation report. A systematic and reproducible method to review CBCT scans can improve the accuracy of the interpretation process, translating into greater precision in terms of diagnosis and planning of endodontic clinical procedures. MEDLINE (PubMed), Web of Science, Google Scholar, Embase and Scopus were searched from inception to March 2023. This narrative review addresses the theoretical concepts, elements of interpretation and applications of the CBCT scan in endodontics. In addition, the contents and rationale for reporting 3D endodontic imaging are discussed.

Global cone-beam computed tomography adoption, usage and scan interpretation preferences of dentists and endodontists

AIM

This study investigated the adoption of cone-beam computed tomography (CBCT) by dentists and endodontists around the world, including their preferences in endodontic CBCT usage.

METHODOLOGY

An online questionnaire surveyed dental association members in Australia and New Zealand, and endodontic association members in Australia, Britain, Canada, Italy, New Zealand and the USA, about their CBCT training history, considerations in acquisition/interpretation, access to and usage of CBCT, preferred scan interpreter, and preferred endodontic scan settings. Data were analysed with Chi-squared, independent sample t-tests, Cochran's Q and McNemar's tests.

RESULTS

Responses from 578 endodontic specialists or postgraduates (Group E) and 185 non-endodontic dentists (Group NE) were included. Continuing professional education (CPE) was the most common source of CBCT training (69.2%). Factors considered in CBCT acquisition/interpretation included beam hardening (75.4%), radiation exposure (61.1%) and patient movement (58.3%). Group E reported higher CBCT usage (90.8%) than Group NE (45.4%, p < .001) and greater workplace access to CBCT (81.1% vs. 25.9%, p < .001). Scans were interpreted by the respondent in most workplace scans (83.3%) and externally taken scans (60.5%); Group E were significantly more likely to interpret themselves than Group NE. Small field of view (83.6%) and high resolution (86.6%) were most preferred as settings for endodontic CBCTs; Group NE were less likely to choose these settings. There were some geographic variations within Group E.

CONCLUSIONS

CBCT training was most commonly acquired via CPE. Endodontic respondents reported very high CBCT usage and access in the workplace. There are educational implications regarding CBCT limitations, appropriate applications and interpretation.

Comparing Radiation Doses in CBCT and Medical CT Imaging for Dental Applications

Background

We are always concerned about radiation exposure during dental imaging procedures. We explore the crucial differences in radiation doses between Cone Beam Computed Tomography (CBCT) and Medical computed tomography (CT) imaging, aiming to shed light on the safety and efficiency of these techniques.

Materials and Methods

In this study, we conducted a comprehensive analysis using state-of-the-art dental imaging equipment. We employed phantoms that simulated real dental scenarios, ensuring accuracy in our measurements. The radiation doses were measured with precision dosimeters, and various exposure settings were tested to obtain a comprehensive dataset.

Results

Our findings reveal substantial differences in radiation doses between CBCT and Medical CT for dental applications. In the case of CBCT, the average effective dose was found to be approximately 100 microsieverts (μSv), making it a preferable choice for routine dental imaging. Medical CT, on the other hand, yielded significantly higher radiation exposure, with an average effective dose exceeding 500 μSv, emphasizing its need for specific clinical scenarios.

Conclusion

In conclusion, the choice between CBCT and Medical CT for dental applications should be made with careful consideration of radiation dose implications. CBCT emerges as the safer and more efficient option for routine dental imaging, offering a lower radiation burden to patients while still delivering high-quality diagnostic images. However, Medical CT may be necessary for specialized cases where the additional radiation risk is justified by diagnostic requirements.

Analysis of implant precision in guided surgery: comparison of two methods

BACKGROUND

Implantology represents the therapy of choice for the rehabilitation of a partially or totally edentulous jaw in a healthy patient. Nowadays, it is possible to exploit of modern preoperative planning software, increasingly precise radiographic examinations (CBCT) and CAD/CAM technologies that allow designing devices directly on the computer to be sent to a milling center which produces the desired product, such as stereolithographic templates.

METHODS

The prospective clinical study in question aims to evaluate the accuracy between two different surgical guides using peek and metal guide bushings. Twenty-nine implants were placed: for the control group, 17 3i, T3 implants were used, while for the test group, 12 Xive S plus implants were used.

RESULTS

The result obtained shows that the deviations in the distribution of the control group and the test group are the same in the apical-coronal, vestibulo-palatal and mesio-distal direction. For the control group, the mean deviation was 1.394±0.644923 at the entry point of the implants and 1.85655±1.0765 at the most apical point of the implants. For the test group the mean deviation was 1.10157±0.312721 at the entry point of the implants and 1.54514±0.572100 at the most apical point of the implants.

CONCLUSIONS

The peek guide bushings have the same deviation as the metal ones. There is no difference in the method used, but precision must be sought in other elements, such as the patient's anatomy and maximum precision in the guide production phase.

Is cone-beam computed tomography (CBCT) an alternative to plain radiography in assessments of dental disease? A study of method agreement in a medically compromised patient population

OBJECTIVES

Poor oral health and dental infections can jeopardize medical treatment and be life-threatening. Due to this, patients with head and neck malignancies, generalized tumor spread, organ transplant, or severe infection are referred for a clinical oral and radiographic examination. The aim of this study was to compare the diagnostic agreement of three radiographic modalities: intraoral radiographs (IO), panoramic radiographs (PX), and cone beam computed tomography (CBCT) for diagnosis of dental diseases.

MATERIALS AND METHODS

Three hundred patients were examined with IO, PX, and CBCT. Periapical lesions, marginal bone level, and caries lesions were diagnosed separately by four oral radiologists. All observers also assessed six teeth in 30 randomly selected patients at two different occasions. Kappa values and percent agreement were calculated.

RESULTS

The highest Kappa value and percent agreement were for diagnosing periapical lesions (0.76, 97.7%), and for the assessment of marginal bone level, it varied between 0.58 and 0.60 (87.8-89.3%). In CBCT, only 44.4% of all teeth were assessable for caries (Kappa 0.68, 93.4%). The intra-observer agreement, for all modalities and diagnoses, showed Kappa values between 0.5 and 0.93 and inter-observer agreement varied from 0.51 to 0.87.

CONCLUSIONS

CBCT was an alternative to IO in diagnosing periapical lesions. Both modalities found the same healthy teeth in 93.8%. All modalities were performed equally regarding marginal bone level. In caries diagnosis, artifacts were the major cause of fallout for CBCT.

CLINICAL RELEVANCE

Intraoral radiography is the first-hand choice for diagnosing dental disease. For some rare cases where intraoral imaging is not possible, a dedicated panoramic image and/or CBCT examination is an alternative.

Monte Carlo simulations of organ and effective doses and dose-length product for dental cone-beam CT

OBJECTIVES

The use of dental cone-beam CT (CBCT) has increased in recent years. We aimed to calculate the organ and effective doses in dental CBCT using Monte Carlo simulation (MCS) and to correlate the effective dose with the dose-length product (DLP), which is a radiation dose index.

METHODS

Organ and effective doses were calculated by MCS using the adult male and female reference phantoms of the International Commission on Radiological Protection publication 110 in a half-rotation scan of the CBCT scanner Veraviewepocs 3Df. The simulations were performed by setting nine protocols in combination with the field-of-view (FOV) and imaging region. In addition, DLPs were calculated by MCS using the virtual CT Dose Index (CTDI) and CBCT phantoms, with the same protocol.

RESULTS

The effective doses were 55 and 195 μSv at the minimum FOV of Φ40 × H40 mm and maximum FOV of Φ 80 × H80 mm, respectively. The organs with the major contribution to the effective dose were the red bone marrow (11.0‒12.8%), thyroid gland (4.0‒12.7%), salivary gland (21.8‒33.2%), and remaining tissues (35.1‒45.7%). Positive correlations were obtained between the effective dose and calculated DLP using the CTDI and CBCT phantoms.

CONCLUSIONS

Organ and effective doses for each protocol of dental CBCT could be estimated using MCS. There was a positive correlation between the effective dose and DLP, suggesting that DLP can be used to estimate the effective dose of CBCT.

Imaging in Third Molar Surgery: A Clinical Update

Third molar surgery is one of the most common surgical procedures performed in oral and maxillofacial surgery. Considering the patient's young age and the often-elective nature of the procedure, a comprehensive preoperative evaluation of the surgical site, relying heavily on preoperative imaging, is key to providing accurate diagnostic work-up, evidence-based clinical decision making, and, when appropriate, indication-specific surgical planning. Given the rapid developments of dental imaging in the field, the aim of this article is to provide a comprehensive, up-to-date clinical overview of various imaging techniques related to perioperative imaging in third molar surgery, ranging from panoramic radiography to emerging technologies, such as photon-counting computed tomography and magnetic resonance imaging. Each modality's advantages, limitations, and recent improvements are evaluated, highlighting their role in treatment planning, complication prevention, and postoperative follow-ups. The integration of recent technological advances, including artificial intelligence and machine learning in biomedical imaging, coupled with a thorough preoperative clinical evaluation, marks another step towards personalized dentistry in high-risk third molar surgery. This approach enables minimally invasive surgical approaches while reducing inefficiencies and risks by incorporating additional imaging modality- and patient-specific parameters, potentially facilitating and improving patient management.

Convex triangular vs. cylindrical field of view: how does the shape of the FOV affect radiation dose?

OBJECTIVE

To compare the dosimetry between convex triangular fields of view (FOV) and similar dimension cylindrical FOVs of two cone-beam computed tomography (CBCT) models.

METHODS

Optically stimulated luminescence dosimeters (OSLDs) were placed in fiducial anatomical locations in an anthropomorphic phantom representing an adult head male for dosimetry scans. Convex triangular FOVs (100 × 80 mm/maxilla-mandible; 100 × 50 mm mandible; 100 × 50 mm/maxilla) from Veraviewepocs 3D R100 (J. Morita, Kyoto, Japan) (R100) and Veraview® X800 (J. Morita, Kyoto, Japan) (X800) and cylindrical FOVs from R100 and X800 (80 × 80 mm/maxilla-mandible; 80 × 50 mm/mandible; 80 × 50 mm/maxilla) were obtained, resulting in 12 different scan protocols. Equivalent doses for each relevant organ/tissue and the effective dose for each protocol were calculated. Mean effective doses were compared by the two-way analysis of variance (ANOVA) with Tukey's post hoc test to evaluate the effect of the FOV and device (α = 0.05).

RESULTS

The effective doses ranged between 69 and 324 μSv for the convex triangular FOVs and 76 and 332 μSv for the cylindrical FOVs. Convex triangular FOVs from the R100 device had effective doses 2.3 to 15.3% lower than their corresponding cylindrical FOVs with similar height (p < 0.05), and that difference ranged between 8.8 and 11.8% for the X800 device (p < 0.05).

CONCLUSION

Convex triangular fields of view delivered slightly lower effective doses than the cylindrical fields of view of similar dimensions in the R100 and X800 CBCT devices.

CLINICAL RELEVANCE

Understanding the influence of the image geometry formation in effective dose allows optimization to reduce patient dose.

Comparison of absorbed doses and organ doses measured with thermoluminescent dosimeters and Gafchromic film for cone beam computed tomography examination of the posterior mandibular region in a head phantom

OBJECTIVES

We aimed to map the correlation between thermoluminescent dosimeters (TLDs) and Gafchromic film for measuring absorbed doses and to compare minimum, maximum, and mean absorbed doses over larger regions of interest and at various craniofacial organs and tissues during cone beam computed tomography (CBCT) exposure of the mandibular third molar region.

STUDY DESIGN

We positioned TLDs at 75 measurement points in a head phantom. Gafchromic film was cut to the same shape as the 5 levels of the phantom and was placed on top of the TLDs. Both dosimetry methods thus included the surface of each level simultaneously. CBCT scans were made using a 5 × 5 cm field of view and a rotation angle of 200°. Measurements included absorbed dose distributions, doses at all 75 points, and minimum, maximum, and mean doses within organs and tissues.

RESULTS

The correlation of point-dose measurements at all TLD sites with doses measured on film was strong (R2 = 0.9687), with greatest correlation at lower doses (<2 mGy). Large deviations between TLD and film measurements of minimum and maximum doses and absorbed doses to the organs occurred at all 5 levels. TLD positioning failed to cover several organ sites; for these, only absorbed dose measurements from the film were available.

CONCLUSIONS

TLDs were unable to sample dose distributions and gradients accurately. The characteristics of Gafchromic LD-V1 film make it a favorable alternative in dental CBCT dosimetry.

A Survey on Cone-beam Computed Tomography Usage Among Endodontists in the United States

INTRODUCTION

The aim of the study was to investigate the accessibility and frequency of cone-beam computed tomography (CBCT) usage and to assess the economic and logistical factors involved with its usage among active American Association of Endodontists (AAE) members, utilizing a web-based survey.

METHODS

A survey of 19 questions was sent to 3,071 AAE members addressing participant access to, along with financial and logistical aspects of CBCT imaging. Descriptive analysis was performed and Fisher exact test utilized to test associations between groups (P < .05).

RESULTS

The overall response rate was 14.7% (n = 544). Ninety-five percent of respondents (n = 486) had an in-office CBCT unit, with those graduating after the year 2000 statistically more likely to have one (P < .05). Utilization of CBCT imaging for every case was reported by 40% of providers. Eighty-nine percent reported taking the scan at the consultation visit and 20% included this charge with the consultation fee. For those who charged for the scan separately, 85% charged more than $100. Providers who paid off their unit did so within 1-2 years (41%), 3-4 years (36%), 4-5 years (12%), and 5+ years (11%). Limited field of view was utilized by 95% of respondents. Fifty-eight percent reported interpreting the scans themselves, 38% send only if pathology is expected, and 3% always send their scans to a radiologist.

CONCLUSIONS

In conclusion, accessibility and utilization of CBCT imaging among United States endodontists has increased and acquisition of this equipment has not made a long lasting financial burden on providers.

The in-vitro accuracy of fiducial marker-based versus markerless registration of an intraoral scan with a cone-beam computed tomography scan in the presence of restoration artifact

OBJECTIVES

To determine the effect of restoration artifact ('metal artifact') on registration accuracy of an intraoral scan and cone-beam computed tomography (CBCT) scan, comparing fiducial marker-based registration with markerless registration.

MATERIALS AND METHODS

A maxillary model was fitted with multiple configurations of zirconia crowns to simulate various states of oral rehabilitation. Intraoral scans and CBCT scans (half and full rotation) were acquired. Registration was performed using markerless (point-based registration with surface-based refinement) and fiducial marker-based registration. Each experimental condition was repeated 10 times (n = 320). The absolute deviation was measured at the canines and first molars, and the average and maximum values were analysed using multiple linear regression.

RESULTS

R2 was 0.874 for average error and 0.858 for maximum error. For markerless registration, there were 0.041 mm (p < .001) and 0.045 mm (p < .001) increases in average and maximum error per crown, respectively. For fiducial marker-based registration, the effect of additional crowns was not statistically significant for average (p = .067) or maximum (p = .438) error. For a full arch of crowns, the regression model predicted average and maximum errors of 0.581 and 0.697 mm for the markerless technique, and 0.185 and 0.210 mm for the fiducial marker-based technique. Overall, the fiducial marker-based technique was more accurate for four or more crowns. The half rotation scan increased average error by 0.021 mm (p = .001) and maximum error by 0.029 mm (p < .001).

CONCLUSIONS

Under the present study's experimental conditions, the fiducial marker-based technique should be considered if four or more full-coverage highly radiopaque restorations are present.

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

INTRODUCTION

This study aimed to assess the influence of the e-vol DX BAR filter on the diagnostic accuracy of complete and incomplete vertical root fractures (VRFs).

METHODS

Twenty single-rooted teeth were selected. The tooth crowns were removed, and the root canals were prepared up to a 40/.06 instrument (ProTaper Next). Each specimen was scanned in a Prexion 3D cone-beam computed tomography (CBCT) device, in a dry human skull, in 4 different situations: no root canal filling, gutta-percha, fiberglass post, and metal post. The specimens were fractured in a universal testing machine by using a customized wedge. Each specimen was reinspected to confirm the presence of incomplete VRFs. Another set of CBCT scans was performed. Then, the fractures were completed in the universal testing machine, the teeth were reinspected, and the CBCT images were acquired again. Images were assessed by using the e-Vol DX software system, with the BAR filter and with the original images, for the diagnosis of VRFs. Statistical analysis was performed by using the DeLong and McNemar tests for the comparison of the area under the receiver operating characteristic curves (AUC), accuracy, sensitivity, and specificity values.

RESULTS

The use of the BAR filter did not improve the diagnostic values of AUC, accuracy, sensitivity, and specificity in both fracture patterns (P > .05). Incomplete VRFs presented significantly lower AUC, accuracy, and sensitivity compared with complete VRFs (P < .0001).

CONCLUSIONS

The BAR filter did not improve the diagnostic accuracy of VRFs. The intracanal materials also did not influence the diagnosis. Incomplete VRFs were highly associated with a decrease in sensitivity.

Evaluation of radiation dose and image quality for dental cone-beam computed tomography in pediatric patients

Children are sensitive to radiation; therefore, it is necessary to reduce radiation dose as much as possible in pediatric patients. In addition, it is crucial to investigate the optimal imaging conditions as they considerably affect the radiation dose. In this study, we investigated the effect of different imaging conditions on image quality and optimized the imaging conditions for dental cone-beam computed tomography (CBCT) examinations to diagnose ectopic eruptions and impacted teeth in children. To achieve our aims, we evaluated radiation doses and subjective and objective image quality. The CBCT scans were performed using 3D Accuitomo F17. All combinations of a tube voltage (90 kV), tube currents (1, 2, 3 mA), fields of view (FOVs) (4 × 4, 6 × 6 cm), and rotation angles (360°, 180°) were used. Dose-area product values were measured. SedentexCT IQ cylindrical phantom was used to physically evaluate the image quality. We used the modulation transfer function as an index of resolution, the noise power spectrum as an index of noise characteristics, and the system performance function as an overall evaluation index of the image. Five dentists visually evaluated the images from the head-neck phantom. The results showed that the image quality tended to worsen, and scores for visual evaluation decreased as tube currents, FOVs and rotation angles decreased. In particular, image noise negatively affected the delineation of the periodontal ligament space. The optimal imaging conditions were 90 kV, 2 mA, 4 × 4 cm FOV and 180° rotation. These results suggest that CBCT radiation doses can be significantly reduced by optimizing the imaging conditions.

Measuring the alveolar bone level in adolescents: A comparison between ultrasound and cone beam computed tomography

BACKGROUND

Cone beam computed tomography (CBCT) is an imaging modality, which is used routinely in orthodontic diagnosis and treatment planning but delivers much higher radiation than conventional dental radiographs. Ultrasound is a noninvasive imaging method that creates an image without ionizing radiation.

AIM

To investigate the reliability of ultrasound and the agreement between ultrasound and CBCT in measuring the alveolar bone level (ABL) on the buccal/labial side of the incisors in adolescent orthodontic patients.

DESIGN

One hundred and eighteen incisors from 30 orthodontic adolescent patients were scanned by CBCT with 0.3-mm voxel size and ultrasound at 20 MHz frequency. The ABL, distance from the cementoenamel junction (CEJ) to the alveolar bone crest (ABC), was measured twice to evaluate the agreement between ultrasound and CBCT. In addition, the intra- and inter-rater reliabilities in measuring the ABL by four raters were compared.

RESULTS

The mean difference (MD) in the ABL between ultrasound and CBCT was -0.07 mm with 95% limit of agreement (LoA) from -0.47 to 0.32 mm for all teeth. For each jaw, the MDs between the ultrasound and CBCT were -0.18 mm (for mandible with 95% LoA from -0.53 to 0.18 mm) and 0.03 mm (for maxilla with 95% LoA from -0.28 to 0.35 mm). In comparison, ultrasound had higher intra-rater (ICC = 0.83-0.90) and inter-rater reliabilities (ICC = 0.97) in ABL measurement than CBCT (ICC = 0.56-0.78 for intra-rater and ICC = 0.69 for inter-rater reliabilities).

CONCLUSION

CBCT parameters used in orthodontic diagnosis and treatment planning in adolescents may not be a reliable tool to assess the ABL for the mandibular incisors. On the contrary, ultrasound imaging, an ionizing radiation-free, inexpensive, and portable diagnostic tool, has potential to be a reliable diagnostic tool in assessing the ABL in adolescent patients.

CBCTs in a Swiss university dental clinic: a retrospective evaluation over 5 years with emphasis on radiation protection criteria

OBJECTIVES

To retrospectively evaluate all cone-beam computed tomography (CBCT) scans acquired from 2017 to 2022 in a Swiss university dental clinic with particular emphasis on radiation protection aspects.

MATERIAL AND METHODS

Radiological databases at the dental clinic of the University of Bern, Switzerland, were explored using a self-developed search algorithm. Data of all acquired CBCT from 01.01.2017 to 27.06.2022 were screened. Exposure parameters (exposure time, exposure angle, milliampere (mA), kilovoltage (kV), field of view (FOV) size), dose area product (DAP), age, and sex of the patient were recorded anonymously. The collected data were analyzed mainly descriptively. Correlations measured the statistical relationships between the variables.

RESULTS

A total of 10,348 CBCT datasets were analyzed. Patient age ranged from 5 to 96 years (mean: 49.4 years, SD: 21.6 years). The number of CBCTs in patients under 25 years was around 20% each year. In total, 10,313 (99.7%) CBCTs were acquired in small to medium FOV (FOV up to 10 cm of height), and 35 (0.3%) in large FOV (height > 10 cm). DAPs of small FOVs were 518.3 ± 233.2 mGycm2 (mean ± SD), of medium FOV 1233 ± 502.2 mGycm2, and of large FOV 2189 ± 368.7 mGycm2. DAP (ρ = 0.4048, p < 0.0001) and kV (ρ = 0.0210, p = 0.0327) correlated positively with age. Reduced scan angle correlated with young age (rpb 0.2729, p < 0.001). mA did not correlate with age (p = 0.3685).

CONCLUSIONS

This study demonstrates that certain well-known radiation protection aspects as the reduction of FOV, mA, kV, and scan angle were only partly considered.

CLINICAL RELEVANCE

Known radiation protection aspects, especially in young patients, should be fully applied in regular clinical practice.

Patient shielding during dentomaxillofacial radiography: Recommendations from the American Academy of Oral and Maxillofacial Radiology

BACKGROUND

The American Academy of Oral and Maxillofacial Radiology established an ad hoc committee to draft evidence-based recommendations and clinical guidance for the application of patient contact shielding during dentomaxillofacial imaging.

TYPES OF STUDIES REVIEWED

The committee reviewed monographs and reports from radiation protection organizations and studies that reported radiation dose to gonads, breasts, and thyroid gland from dentomaxillofacial imaging.

RESULTS

Considering the absence of radiation-induced heritable effects in humans and the negligible dose to the gonads and fetus from dentomaxillofacial imaging, the committee recommends discontinuing shielding of the gonads, pelvic structures, and fetuses during all dentomaxillofacial radiographic imaging procedures. On the basis of radiation doses from contemporaneous maxillofacial imaging, the committee considered that the risks from thyroid cancer are negligible and recommends that thyroid shielding not be used during intraoral, panoramic, cephalometric, and cone-beam computed tomographic imaging.

PRACTICAL IMPLICATIONS

This position statement informs and educates the reader on evolving radiation protection practices and provides simple, unequivocal guidance to dental personnel to implement these guidelines. State and local authorities should be contacted to update regulations to reflect these recommendations.

Evaluation of the feasibility of a multisource CBCT for maxillofacial imaging

Objective. The aim of this study was to investigate the feasibility of improving the image quality and accuracy of cone beam computed tomography (CBCT) by replacing the conventional wide cone angle x-ray tube with a distributed x-ray source array positioned in the axial direction.Approach. The multisource CBCT (ms-CBCT) design was experimentally simulated using a benchtop scanner with a carbon nanotube x-ray tube and a flat-panel detector. The source was collimated and translated in the axial direction to simulate a source array with a reduced cone angle for each beam. An adjacent scatter ratio subtraction (ASRS) method was implemented for residual scatter reduction. Several phantoms were imaged using the ms-CBCT and conventional CBCT configurations under otherwise similar conditions. The Requirements of the ms-CBCT design on the x-ray source and detector were evaluated.Main results. Compared to the conventional CBCT, the ms-CBCT design with 8 sources and ASRS significantly improved the image quality and accuracy, including: (1) reducing the cupping artifact from 15% to 3.5%; (2) reducing the spatial nonuniformity of the CT Hounsfield unit values from 38.0 to 9.2; (3) improving the contrast-to-noise ratio of the low contrast objects (acrylic and low density polyethylene inserts) against the water-equivalent background by ∼20% and (4) reducing the root-mean-square error of the HU values by 70%, from 420.1 to 124.4. The imaging dose and scanning time used by the current clinical CBCT for maxillofacial imaging can be achieved by current source and detector technologies.Significance. The ms-CBCT design significantly reduces the scatter and improves the image quality and accuracy compared to the conventional CBCT.

Assessment of Scattered Dose to the Eye in Dentistry: A Systematic Review

Cone-beam computed tomography (CBCT) is a tool for dental imaging of impactions, maxillofacial discrepancies, facial trauma, and tumors. In addition, It is used in treatment planning for dental implants, orthognathic surgery, and general maxillofacial surgery. There are no standardized methods for utilizing CBCT dosimetry, and there is no consensus among dental and medical physics health professionals regarding dental CBCT imaging procedures. The eyes and thyroid glands are radiosensitive organs that lie outside the primary beam but receive a significant amount of radiation due to scattered radiation. This study aimed to assess the dose to eye lens in patients imaged using CBCT. This review aims to evaluate the scattered doses to the eye from CBCT among adult patients seeking dental treatment. The search included published articles in the Web of Science, PubMed (MeSH and Web PubMed), Medline, and Google Scholar databases using the appropriate keywords from January 2010 to July 2022. The inclusion criteria were based on the method of dose measurement (phantom studies using Optically stimulated luminescence (OSL) and Thermoluminescent dosimeter (TLD), language, and type of protocol used. A literature search was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist and flow chart. Out of 653 articles identified, 5 met the inclusion criteria. The results show that the scattered radiation dose ranged between 0.103 mSv and 8.3 mSv. This variation exists due to the difference in the field of vision (FOV), phantom exposure, dosimeters used, degree of rotation in the protocol, and finally, the scanner used. The scattered dose to the eye from CBCT is higher than the background radiation, with huge variability in the range of the dose measured. Clear guidelines for utilizing CBCT should be implemented, and dose reference levels should be established for benchmarking and optimization in practice.

Exploring the Validity of an Optoelectronic Integrated Cone Beam Computed Tomography Jaw Tracking System

Jaw motion tracking functionalities of cone beam computed tomography (CBCT)-scanners can visualize, record, and analyze movements of the mandible. In this explorative study, the validity of the 4D-Jaw Motion module (4D-JM) of the ProMax 3D Mid CBCT scanner (Planmeca, Helsinki, Finland) was tested in vitro. The validity of the 4D-JM was accepted if values differed less than 0.6 mm (three voxels sizes) from the gold standard. Three dry human skulls were used. CBCT scans, the gold standard, were taken in eight jaw positions and exported as three-dimensional (3D) models. Individualized 3D-printed dental wafers ensured the correct positioning of the mandible. Jaw positions were recorded with the 4D-JM tracking device and exported as 3D models. The coordinates of six reference points for both superimposed 3D models were obtained. The differences in the x, y and z-axis and the corresponding vector differences between gold standard 3D models and 4D-JM models were calculated. For the mandible 10% and for the maxilla 90% of the vector differences fell within 0.6 mm of the gold standard. With an increasing vertical jaw opening, larger differences between the gold standard and the 4D-JM 3D models were found. The smallest differences of the mandible were observed on the x axis. In this study, the 4D-JM validity was not acceptable by the authors' predefined standards.

Evaluation of Third Molar Maturity Index by Cone Beam Computed Tomography in Legal Age Estimation: A Preliminary Study

ABSTRACT

This retrospective study aimed to evaluate the accuracy and applicability of the third molar maturity index (I 3M ) for discriminating Turkish minors from adults, and its relationship with chronological age using cone beam computed tomography (CBCT). A total of 122 CBCT scans of Turkish individuals (55 boys and 67 girls) aged 13 to 23 years were evaluated using the I 3M cutoff value. Chronological age gradually decreased as the I 3M value increased. The overall accuracy was 95.9%. The sensitivity and specificity of this test were 93.5% and 97.4%, respectively. Positive predictive value was 95.6%. The intraclass correlation coefficient values of the I 3M for the intraobserver and interobserver agreements were 0.998 and 0.996, respectively. This study showed relatively higher reproducibility of measurements on CBCT scans than on panoramic radiographs in the literature. Cone beam computed tomography may be advantageous and preferred over panoramic radiographs in distinguishing the legal age threshold of 18 years according to Cameriere's method when a more extensive investigation is needed to support the solution of challenging and uncertain cases in forensic medicine.

Morphological Studies to Identify the Nasopalatine and Inferior Alveolar Nerve Using a Special Head and Neck MRI Coil

OBJECTIVES

Procedures in oral and maxillofacial surgery bear a high risk of nerve damage. Three-dimensional imaging techniques can optimize surgical planning and help to spare nerves. The aim of this study was to investigate the diagnostic value of a 1.5 T magnetic resonance imaging (MRI) scanner with a dedicated dental signal amplification coil for the assessment of nerves in the oral cavity as compared with cone beam computed tomography (CBCT).

METHODS

Based on 6 predefined criteria, the assessability of the inferior alveolar and nasopalatine nerves in CBCT and MRI with a dedicated 4-channel dental coil were compared in 24 patients.

RESULTS

Compared with CBCT, MRI with the dental coil showed significantly better evaluability of the inferior alveolar nerve in the sagittal and axial plane and the nasopalatine nerve in the axial plane. In the sagittal plane; however, the assessability of the nasopalatine nerve was significantly better in CBCT as compared with MRI. Yet, pertaining to overall assessability, no significant differences between modalities were found.

CONCLUSIONS

In this pilot study, it can be reported that 1.5- T MRI with a dedicated dental coil is at least equivalent, if not superior, to CBCT in imaging nerve structures of the stomatognathic system.

CLINICAL RELEVANCE

Preoperative, 3-dimensional images are known to simplify and refine the planning and execution of operations in maxillofacial surgery. In contrast to computed tomography and CBCT, MRI does not cause radiation exposure while enabling visualization of all relevant hard and soft tissues and, therefore, holds an advantage over well-established techniques.

Effect of field of view and voxel size on CBCT-based accuracy of dynamic navigation in endodontic microsurgery: an in vitro study

INTRODUCTION

This study aimed to evaluate the influence of field of view (FOV) and voxel size on the accuracy of dynamic navigation (DN)-assisted endodontic microsurgery (EMS).

METHODS

Nine sets of maxillary and mandibular three-dimensional-printed jaw models composed of 180 teeth were divided into nine groups with different FOVs (80 × 80 mm, 60 × 60 mm, and 40 × 40 mm) and voxel sizes (0.3, 0.16, and 0.08 mm). The endodontic DN system was used to plan and execute the EMS. The accuracy of the DN-EMS was represented by the platform deviation, end deviation, angular deviation, resection angle, and resection length deviation. Statistical analyses were performed using SPSS 24.0, and the significance level was set at p < 0.05.

RESULTS

The average platform, end, angular, resection angle, and resection length deviation were 0.69 ± 0.31 mm, 0.93 ± 0.44 mm, 3.47 ± 1.80°, 2.35 ± 1.76°, and 0.41 ± 0.29 mm, respectively. No statistically significant differences in accuracy were observed between the nine FOV and voxel size groups.

CONCLUSION

FOV and voxel size did not appear to play an important role in the accuracy of DN-EMS. Considering the image quality and radiation dose, it is reasonable to select a limited FOV (such as 40 × 40 mm and 60 × 60 mm) to cover only the registration device, involved teeth, and periapical lesion. The voxel size should be selected according to the required resolution and CBCT units.

Panoramic dental tomosynthesis imaging by use of CBCT projection data

Dental CBCT and panoramic images are important imaging modalities used in dental diagnosis and treatment planning. In order to acquire a panoramic image without an additional panoramic scan, in this study, we proposed a method of reconstructing a panoramic image by extracting panoramic projection data from dental CBCT projection data. After specifying the patient's dental arch from the patient's CBCT image, panoramic projection data are extracted from the CBCT projection data along the appropriate panoramic scan trajectory that fits the dental arch. A total of 40 clinical human datasets and one head phantom dataset were used to test the proposed method. The clinical human dataset used in this study includes cases in which it is difficult to reconstruct panoramic images from CBCT images, such as data with severe metal artifacts or data without teeth. As a result of applying the panoramic image reconstruction method proposed in this study, we were able to successfully acquire panoramic images from the CBCT projection data of various patients. The proposed method acquires a universally applicable panoramic image that is less affected by CBCT image quality and metal artifacts by extracting panoramic projection data from dental CBCT data and reconstructing a panoramic image.

Computerized three-dimensional cephalometric template for Thai adults

Cephalometry is essential in several fields of study. These include health science, anthropology, and forensic studies. Furthermore, cephalometric norms are essential for numerous disciplines in the health sciences, such as clinical anatomy, plastic surgery, pediatrics, pediatric dentistry, orthodontics, oral and maxillofacial surgery, and forensic medicine. Three-dimensional (3D) cephalometric templates offer an advanced but simple method for these specialties. This study aimed to establish cephalometric norms by developing 3D templates for Thai adults, based on cephalometric landmark coordinates obtained from skull cone-beam computed tomography (CBCT) scans of individuals with normal skeletal patterns. Full-head CBCT scans of 45 individuals (20 men and 25 women) were obtained from the archive. All had a Class I molar relationship with minor crowded teeth. The scans were captured in a normal head position, and the coordinates of 21 important cephalometric landmarks were identified using Slicer 4.10.2 software. Manual affine transformation of all landmarks was used to transfer medical image coordinates (Digital Imaging and Communications in Medicine [DICOM] or Right-Anterior-Superior [RAS] systems) to Cartesian universal coordinates. Intraclass correlation coefficients (ICC) and Bland-Altman (BA) plots were used to assess inter- and intra-examiner reliability (ICC = 0.961-1.000, BA mean errors = -0.1 mm). Important cephalometric measurements were compared to the most relevant and recent study with a sample size of 200. Most measurements showed no statistical difference (one-sample t-test, p > 0.05). Independent samples t-tests revealed that there was no statistically significant difference in the X and Y axes; however, most mean coordinates between men and women in the Z-axis coordinates were statistically significant. Consequently, 3D cephalometric templates were generated separately for adult Thai men and women using landmark coordinates. Although they are available for all disciplines at no cost through QR codes, these templates should be used with care, especially for the upper and lower incisor angulation. The application and future development of each specialty are also described here.

CBCT Evaluation of Periapical Pathologies in Maxillary Posterior Teeth and Their Relationship with Maxillary Sinus Mucosal Thickening

In modern dentistry, radiographic imaging is crucial for examining the connection between the maxillary sinus floor and the root apices of the maxillary posterior teeth, particularly when the periapical region is affected by pathology that could result in infectious, inflammatory, or traumatic changes in the maxillary sinus. This study aimed to investigate the prevalence of periapical pathologies in the maxillary posterior teeth and their relationship with maxillary sinus mucosal thickening by using cone-beam computed tomography scans. This retrospective study was conducted on 420 digitized CBCT images which were scanned in sagittal, axial, and coronal views. Out of 420 total images, 223 (53.1%) were of males and 197 (44.9%) were of females. The data were analyzed using SPSS version 28. A total of 2936 posterior maxillary teeth were tested for periapical pathology (PP), 1477 on the right side and 1459 on the left side. In terms of gender, there was no significant relationship between PP in maxillary posterior teeth on both sides and mucosal thickness of the maxillary sinus (p > 0.05). A significant relationship was found between PP in maxillary posterior teeth on both sides and maxillary sinus mucosal thickening (p < 0.05). This study concluded that the prevalence of periapical pathology in the maxillary posterior teeth was significantly associated with a rise in the incidence of maxillary sinus mucosal thickening. Moreover, the primary causative factor for the pathophysiology of the odontogenic maxillary sinus was the periapical pathology in both maxillary first molars.

DIAGNOSTIC PERFORMANCE OF CONE-BEAM COMPUTED TOMOGRAPHY TO DIAGNOSE IN VIVO/IN VITRO ROOT RESORPTION: A SYSTEMATIC REVIEW AND META-ANALYSIS

BACKGROUND

This review analyses the diagnostic performance of cone-beam computed tomography (CBCT) for the in vivo/in vitro detection of external root resorption (ERR) and critically analyses current and past methods of measuring or classifying ERR in vivo/in vitro in terms of radiation doses and cumulative radiation risks.

METHODS

A diagnostic test accuracy (DTA) protocol was used for a systematic review of diagnostic methods following PRISMA guidelines. The protocol was registered with PROSPERO (ID: CRD42019120513). A thorough and exhaustive electronic search of 6 core electronic databases was performed, applying the ISSG Search Filter Resource. The eligibility criteria were designed [problem-intervention-comparison-outcomes (PICO) statement: Population, Index test, Comparator, Outcome] and methodological quality was assessed by QUADAS-2.

RESULTS

Seventeen papers were selected from a total of 7841 articles. Six in vivo studies were assessed as having a low risk of bias. The overall sensitivity and specificity of CBCT for diagnosis of ERR was 78.12% and 79.25%, respectively. The highest and lowest sensitivity and specificity of CBCT for diagnosis of external root resorption are 42%-98% and 49.3%-96.3%.

DISCUSSION

Most of the selected studies reported quantitative diagnoses with single linear measurements of ERR even though multislice radiographs were available. The cumulative radiation dose (μS) to radiation-sensitive structures, such as the bone marrow, brain and thyroid, was observed to increase using the 3-dimensional (3D) radiography methods reported.

CONCLUSIONS

The highest and lowest sensitivity and specificity of CBCT for diagnosis of external root resorption are 42%-98% and 49.3%-96.3%. The minimum and maximum effective doses of dental CBCT for external root resorption diagnosis are 34 μSv and 1073 μSv.

Does cone-beam computed tomography examination increase the micronuclei frequency in the oral mucosa exfoliated cells? A systematic review and meta-analysis

OBJECTIVE

This systematic review (SR) with meta-analysis aimed to evaluate the frequency of micronuclei in the oral mucosa exfoliated cells after cone-beam computed tomography (CBCT) examination.

METHODS

We performed language-independent computer-assisted data searches using PubMed databases, Cochrane, Embase, Web of Science all databases, and Google Scholar. The literature on micronucleus (MN) frequency of clinical trials before and after CBCT examination was included. The frequency of MN in exfoliated cells of the human oral mucosa was the primary outcome of the study. All statistical analyses were performed with R (version 4.1.0), RStudio (version 2022.02.2 + 485) software, and Meta packages (version 5.2-0). Two reviewers independently assessed the quality of the included studies by the EPHPP (Effective Public Health Practice Project) Modified scale with minor modifications. The heterogeneity of the data was analyzed using I² statistics, in which I² > 50% was considered substantial heterogeneity.

RESULTS

A total of 559 articles were selected through the search strategy. After screening titles and abstracts, nine full-text manuscripts were assessed for eligibility, and six observational studies were included in the meta-analysis. The present study showed a significant increase in MN frequency of human oral mucosal exfoliated cells 10 days after CBCT examination compared to baseline (SMD = - 0.56, 95%-CI = - 0.99 ~ - 0.13, p = 0.01). Because of the high heterogeneity among the studies (I² = 72%), after removing one study that was the main source of heterogeneity, excluding the study (I² = 47%), the common-effect model was chosen, and the meta-analysis also showed that the frequency of MN in human oral mucosa exfoliated cells increased significantly 10 days after CBCT examination (SMD =  - 0.35, 95%-CI =  - 0.59 ~  - 0.11, p = 0.004).

CONCLUSION

This review suggested that CBCT examination increases the frequency of micronuclei in oral mucosal exfoliated cells.

[Radiological methods for age diagnostics : Clinical and forensic aspects]

Age diagnostics play an increasing role in radiology. Medical and forensic questions are indications for the application of age diagnostics. In addition to X‑rays of the hand in childhood, panoramic tomography and computed tomography are currently the standard procedures. Alternative modalities without ionizing radiation (sonography, magnetic resonance imaging) have not (yet) been established. The purpose of this article is to present the indications and methods of age diagnostics in the clinical and forensic contexts and to familiarize you with their advantages and disadvantages as well as the possibility of determining the final length.

As low as diagnostically acceptable dose imaging in maxillofacial trauma: a reference quality approach

OBJECTIVES

As-low-as-diagnostically-acceptable (ALADA) doses are substantially lower than current diagnostic reference levels. To improve dose management, a reference quality approach was tested in which phantom quality metrics of a clinical ALADA dose reference protocol were used to benchmark potential ALADA dose protocols for various scanner models.

METHODS

Spatial resolution, contrast resolution, contrast-to-noise ratio (CNR) and subjective noise and sharpness were evaluated for a clinical ALADA dose reference protocol at 80 kV and 40 mA (CTDIvol 2.66 mGy) and compared with test protocols of two CT scanners at 100 kV and 35 mA (3.08-3.44 mGy), 80 kV and 54-61 mA (2.65 mGy), 80 kV and 40 mA (1.73-1.92 mGy), and 80 kV and 21-23 mA (1.00-1.03 mGy) using different kernels, filtered backprojection and iterative reconstructions. The test protocols with the lowest dose showing quality metrics non-inferior to the reference protocol were verified in a cadaver study by determining the diagnostic accuracy of detection of maxillofacial fractures and CNR of the optical nerve and rectus inferior muscle.

RESULTS

36 different image series were analysed in the phantom study. Based on the phantom quality metrics, potential ALADA dose protocols at 1.73-1.92 mGy were selected. Compared with the reference images, the selected protocols showed non-inferiority in the detection and classification of maxillofacial fractures and non-inferior CNR of orbital soft tissues in the cadaver study.

CONCLUSIONS

Reference quality metrics from clinical ALADA dose protocols may be used to guide selection of potential ALADA dose protocols of different CT scanners.

Cone beam computed tomography: What's left to know?

The use of cone beam computed tomography (CBCT) in dentistry has grown exponentially since its inception and that trend continues. Though CBCT has become routine to some, its popularity in dentistry only demonstrates that education in CBCT is needed now more than ever. This presentation covers key components to consider when purchasing a CBCT unit and describes concepts in interpretation and radiation safety.