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

Converting dose-area product to effective dose in dental cone-beam computed tomography using organ-specific deep learning

OBJECTIVE

To develop an accurate method for converting dose-area product (DAP) to patient dose for dental cone-beam computed tomography (CBCT) using deep learning.

METHODS

A total of 24 384 CBCT exposures of an adult phantom were simulated with PCXMC 2.0, using permutations of tube voltage, filtration, source-isocenter distance, beam width/height, and isocenter position. Equivalent organ doses as well as DAP values were recorded. Next, using the aforementioned scan parameters as inputs, neural networks (NN) were trained using Keras for estimating the equivalent dose per DAP for each organ. Two methods were explored for positional input features: (1) "Coordinate" mode, which uses the (continuous) XYZ coordinates of the isocentre, and (2) "AP/JAW" mode, which uses the (categorical) anteroposterior and craniocaudal position. Each network was trained, validated, and tested using a 3/1/1 data split. Effective dose (ED) was calculated from the combination of NN outputs using ICRP 103 tissue weighting factors. The performance of the resulting NN models for estimating ED/DAP was compared with that of a multiple linear regression (MLR) model as well as direct conversion coefficients (CC).

RESULTS

The mean absolute error (MAE) for organ dose/DAP on the test data ranged from 0.18% (bone surface) to 2.90% (oesophagus) in "Coordinate" mode and from 2.74% (red bone marrow) to 14.13% (brain) in "AP/JAW" mode. The MAE for ED was 0.23% and 4.30%, respectively, for the two modes, vs. 5.70% for the MLR model and 20.19%-32.67% for the CCs.

CONCLUSIONS

NNs allow for an accurate estimation of patient dose based on DAP in dental CBCT.

Improvement of image quality of dentomaxillofacial region in ultra-high-resolution CT: a phantom study

OBJECTIVES

The purpose of this study was to compare the image quality of ultra-high-resolution CT (U-HRCT) with that of conventional multidetector row CT (convCT) and demonstrate its usefulness in the dentomaxillofacial region.

METHODS

Phantoms were helically scanned with U-HRCT and convCT scanners using clinical protocols. In U-HRCT, phantoms were scanned in super-high-resolution (SHR) mode, and hybrid iterative reconstruction (HIR) and filtered-back projection (FBP) techniques were performed using a bone kernel (FC81). The FBP technique was performed using the same kernel as in convCT (reference). Two observers independently evaluated the 54 resulting images using a 5-point scale (5 = excellent diagnostic image quality; 4 = above average; 3 = average; 2 = subdiagnostic; and 1 = unacceptable). The system performance function (SPF) was calculated for a comprehensive evaluation of the image quality using the task transfer function and noise power spectrum. Statistical analysis using the Kruskal-Wallis test was performed to compare the image quality among the 3 protocols.

RESULTS

The observers assigned higher scores to images acquired with the SHRHIR and SHRFBP protocols than to those acquired with the reference (P < 0.0001 and P < 0.0001, respectively). The relative SPF value at 1.0 cycles/mm in SHRHIR and SHRFBP compared to the reference protocol were 151.5% and 45.6%, respectively.

CONCLUSIONS

Through phantom experiments, this study demonstrated that U-HRCT can provide superior-quality images compared to conventional CT in the dentomaxillofacial region. The development of a better image reconstruction method is required to improve image quality and optimize the radiation dose.

Suboptimal patient positioning with panoramic and CBCT imaging: effects on dose

OBJECTIVE

This study examined the effects of changes in patient positioning on radiation exposure for panoramic and cone beam computed tomography (CBCT) radiographic examinations by measuring effective dose (E) and equivalent doses.

STUDY DESIGN

Simulated radiographic examinations with optimal and suboptimal positioning-anterior shift by 1 centimeter (cm), posterior shift by 1 cm, chin lowered by 10 degrees (°), chin elevated by 10°, rotation by 10°, and lateral shift by 1 cm-were conducted using a tissue-equivalent phantom and optically-stimulated luminescent dosimeters. Exposures were made with the RAYSCAN Alpha Plus 160 X-ray unit using the following exposure parameters: panoramic, 80 kVp, 14 mA, and 13.9s; CBCT (10 x 10 cm FOV), 90 kVp, 10 mA, and 14.0s; CBCT (16 x 10 cm FOV), 90 kVp, 11 mA, and 14.0 s.

RESULTS

All suboptimal panoramic conditions except rotation demonstrated significant decreases in E. Chin elevation during CBCT imaging reduced E with the 10 × 10 cm FOV (P = .0003) and 16 × 10 cm FOV (P < .0001), as well as the equivalent dose to the thyroid gland (P < .0001 for both FOVs).

CONCLUSIONS

Suboptimal positioning did not significantly increase E for either panoramic or CBCT exposures. Chin elevation decreased E in the CBCT protocols, with notable decreases in equivalent dose to the thyroid gland.

Interdisciplinary Approach to Managing Complex Traumatic Dental Injuries in the Young Permanent Dentition

Traumatic dental injuries (TDIs) are a frequent challenge in pediatric dentistry, requiring a coordinated interdisciplinary approach for successful management. These injuries can affect various dental tissues and pose significant diagnostic and therapeutic challenges, particularly in young patients with developing dentition. This review aims to explore the complexities of managing TDIs in young permanent dentition, focusing on the role of orthodontics, endodontics, and other specialties in providing comprehensive care. We highlight the importance of interdisciplinary collaboration in achieving optimal functional and aesthetic outcomes, emphasizing the need for updated diagnostic tools and treatment protocols tailored to the growing child. Specific recommendations are provided for clinicians on integrating orthodontic and endodontic management in trauma cases, focusing on minimizing complications and ensuring long-term prognosis.

CBCT-based assessment of apical root resorption and alveolar bone height following orthodontic treatment of Class I moderate crowding with labial vs. lingual fixed appliances in young adults: A randomized controlled trial

OBJECTIVES

Apical root resorption and alveolar bone loss are potential complications associated with orthodontic treatment. This study aimed to assess apical root resorption and alveolar bone height following orthodontic treatment of moderate crowding with labial vs. lingual fixed appliances using CBCT imaging.

SUBJECTS AND METHODS

All patients meeting the eligibility criteria were included from March 2022 to June 2022 at the University of Damascus Faculty of Dentistry, Department of Orthodontics. The study involved patients diagnosed with Class I malocclusion and moderate crowding in both arches that could be treated on a non-extraction basis. Participants were randomly divided into two groups. One group was treated using lingual appliances (DTC® IN-Tendo JK-SL, DTC Medical Apparatus Co., Hangzhou, China) with a 0.018-inch slot. The sequence of archwires used included 0.012″, 0.014 0.016″ nickel-titanium, 0.016″×0.022″ TMA, 0.016″×0.022″ stainless steel, and 0.017″×0.025″ stainless steel. The other group received treatment with labial straight-wire appliances (AO Mini Master® - MBT System, metal brackets, Sheboygan, WI, USA) also featuring a 0.018-inch slot. The sequence of archwires used was 0.012″, 0.014″, 0.016″ nickel-titanium, 0.016″×0.022″ nickel-titanium, 0.016 and 0.017″×0.025″ stainless steel. The CBCT images were taken before the commencement of treatment (T0) and one day following the end of treatment (T1). The apical root resorption and alveolar bone height of the upper and lower teeth were assessed at these assessment times. Paired-sample t-test used to analyse the intergroup differences, while a two-sample t-test was employed to assess intragroup changes. The significance level was set at P<0.004 after adjustment using Bonferroni's correction.

RESULTS

Out of forty patients, nineteen patients in each group were included in the statistical analysis (16 men and 24 women; mean age: 21.3years). In both groups, there was a significant decrease in the lengths of all studied teeth at T1 (P<0.004). The apical resorption was significantly greater in the lingual appliance group for lower central and lateral incisors compared to the labial appliance group (0.64mm, 0.7, respectively). The mean lingual bone loss in the lingual appliances was statistically greater than that in the labial appliances for lower central incisors (0.53mm), while the mean buccal bone loss in the labial appliance group was statistically greater than that in the lingual appliance group for the lower lateral incisors (0.52mm).

CONCLUSIONS

The use of DTC® lingual or AO Mini Master® labial brackets with archwire sequences is associated with clinically acceptable mild to moderate root resorption and clinically insignificant alveolar bone loss when treating moderate crowding. The record resorption in both cases is less than 1.34mm. The lingual appliances cause greater resorption of lower incisors than labial appliances. Lingual bone loss is greater with lingual orthodontic appliances for lower central incisors, while vestibular bone loss is greater with labial orthodontic appliances for the lower later al incisors.

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.

Radiation dose assessment during dental cone beam computed tomography procedures in Sri Lanka towards establishing a dose reference level

This study assesses radiation doses in cone beam computed tomography (CBCT) procedures in Sri Lanka, with the goal of establishing initial diagnostic reference levels (DRLs). Data from 1162 retrospective scans across four institutions were analyzed, and the medians of the pooled dose distribution for seven clinical indication categories were presented as the DRL values. The proposed DRLs based on clinical indications are 1013 mGy·cm2 for pathological conditions including cysts, tumors, and lesions, 1307 mGy·cm2 for implant planning, 1266 mGy·cm2 for presurgery assessment, and 1585 mGy·cm2 for evaluation of sinus and nasal pathology, temporomandibular disorder, and facial trauma. Considerable variability in doses across facilities was observed, driven by differences in equipment and imaging practices. Therefore, this study recommends adopting suggested DRL values as benchmarks, standardizing protocols to reduce dose variability, and implementing a national framework for regular updates of DRL values.

Monte Carlo simulation study of the effect of thyroid shielding on radiation dose in dental cone beam CT in an adult male phantom

In this paper, the effect of thyroid collars on radiation dose during dental cone-beam computed tomography (CBCT) was evaluated using Monte Carlo simulations and to calculate the effective dose underestimated for the actual CBCT examination due to accounting only for the head and neck. Three thyroid collar models that covered the surface of the phantom were established according to the International Commission on Radiological Protection (ICRP) adult-male mesh-type reference computational phantoms, and a Particle and Heavy Ion Transport code System was used to calculate the equivalent and effective doses of ICRP phantom when different thyroid shielding protocols were used in NewTom VGi evo CBCT, considering one medium (12 × 8 cm) and one small (8 × 5 cm) fields of view (FOVs), and two centre positions were used for each FOV. In four CBCT scanning scenarios, thyroid shielding reduced the equivalent dose for many tissues. The results indicate that the portion of the thyroid collar that wraps around the neck has the main role in reducing the effective dose during dental CBCT examinations, and the higher the axial level of the top of the shielding, the better the effectiveness of the shielding. In this study, the underestimation of the effective dose due to considering only the head and neck was 3.1%-8.1%, and the underestimation was more pronounced in larger FOVs.

Clinical Efficacy of CBCT and 3D-Printed Replicas in Molar Autotransplantation: A Controlled Clinical Trial

BACKGROUND/AIM

To evaluate the efficacy of the combined cone-beam (CBCT)/3D-replicas protocol on the clinical and radiographic outcomes of autotransplanted molars.

MATERIAL AND METHODS

Controlled clinical trial registered ISRCTN13563091 from August 2019 to September 2022. Patients aged 13-22 years requiring permanent premolar extraction and having at least one non-erupted third molar were enrolled at the Institute of Stomatology, Stradins University, Riga, Latvia. Patients in the 3D-replicas (n = 30) underwent maxillary CBCT scans and had 3D-printed replicas of the third molar fabricated, while the control group (n = 28) did not. The clinical outcomes included tooth mobility, bleeding on probing, and periodontal pocket depth assessed at 3, 6, and 12 months. The radiographic outcomes included root development, obliteration, periapical status, and crown changes at 12 months.

RESULTS

Of the 55 patients assigned to interventions, 46 completed the study. No significant differences in survival and radiographic outcomes were found between the control (n = 22) and 3D-replica group (n = 24): root development (p = 0.3), root resorption (p = 0.057), periapical status (p = 0.7), and crown/root ratio change (p = 0.4). Logistic regression showed no significant associations between radiologic predictors (root resorption: p = 0.4; periapical status: p > 0.9; root development: p = 0.8). Significant clinical outcome predictors included total operative time (β = 0.0043, p = 0.049), Moorrees' stage (stage 4: β = -0.31, p < 0.001; stage 5: β = -0.39, p < 0.001), and four donor placement times (β = 0.93, p < 0.001), but group assignment was not a significant predictor.

CONCLUSIONS

The CBCT/3D-replica protocol showed no significant differences in the clinical or radiological outcomes. The high success rates in both groups suggest that the protocol is valuable primarily for optimizing surgical efficiency and as a training tool for clinicians.

Scout images acquired prior to cone beam CT acquisitions: reproducibility of findings and added diagnostic information

OBJECTIVES

The aim of the present study was to assess the reproducibility of findings in cone beam CT (CBCT) scout images. Furthermore, the study aimed to assess whether a scout image shows pathology not seen within the CBCT volume (ie, added diagnostic information) and therefore must be assessed on the same terms as the full volume.

METHODS

Using a retrospective design, 233 CBCT reports and scout images were assessed. Kappa statistics and percentage of accordance were used to evaluate intra- and inter-observer reproducibility as well as agreement between scout and CBCT report.

RESULTS

Intra- and inter-observer reproducibility was overall low (kappa ranging from -0.008 to 1.000). Agreement between findings reported in the CBCT and scout was also low. One hundred fourteen impacted teeth, one apical periodontitis, and two sinus conditions seen in the scout image were not registered in the full volume report due to the extended size of the scout image.

CONCLUSIONS

Reproducibility of findings in scout images compared to CBCT volumes was low, and the scout showed very little additional diagnostic information.

ADVANCES IN KNOWLEDGE

This study shows that although the reproducibility of viewing scout images is low, rare findings can go undetected if the scout is not assessed. Legislation regarding interpretation of scout images needs to be discussed.

Variations in head tilt during the acquisition of cone beam computed tomography scans and their effects on effective radiation dose

OBJECTIVES

This study evaluated the impact of variations in anteroposterior and lateral tilts of patients head on radiation-weighted doses to organs/tissues and effective doses using 3 different cone beam computed tomography (CBCT) machines.

METHODS

An anthropomorphic phantom was used to estimate radiation doses in 3 CBCT machines (OP300, Eagle X 3D, and Eagle Edge). Thermoluminescent dosimeters were placed in regions corresponding to pre-stablished organ/tissues. CBCT examinations from the posterior mandible and anterior maxilla regions were acquired, with 3 different anteroposterior angulations (0°, 30°, and 45°), and from the posterior mandible in 3 different lateral angulations (0°, 20° to the left, and 20° to the right side). Radiation-weighted doses for each organ/tissue and effective doses were calculated for each machine and angulation.

RESULTS

For the posterior mandible acquisitions, anteroposterior angulations of the head at 30° and 45° yielded a reduction in effective doses in all 3 devices. A 20° tilt to the right side resulted in lower doses than to the left [same side as the field of view (FOV)]. For the anterior maxilla, increased anteroposterior angulation was associated with reduction in effective dose in 2 devices.

CONCLUSIONS

Effective doses are lower when small FOV CBCT exams of the posterior mandible and anterior maxilla are acquired with increased anteroposterior head angulation at 30° and 45°. For FOV in the posterior mandible, a 20° lateral tilt towards the side opposite to the FOV also yields lower effective doses. The main contribution to these dose reductions is the decrease in dose to salivary glands.

Tooth segmentation by low-dose CBCT for orthodontic treatment planning : Explorative ex vivo validation

PURPOSE

Three-dimensional imaging has become an increasingly important component of orthodontics. Associated with this, however, is a higher radiation exposure for patients. New cone-beam computed tomography (CBCT) devices have been developed that can provide low-dose CBCT (LD-CBCT). We hypothesized that LD-CBCT is as precise and reproducible as standard high-dose CBCT (HD-CBCT) in segmenting roots and crowns as well as measuring tooth length.

METHODS

HD-CBCT and LD-CBCT scans were taken of four human cadaveric heads. Thirty single-rooted teeth were segmented twice by one investigator. The length of each tooth was also measured. Lin's concordance correlation coefficient (CCC) was calculated to assess the agreement of HD-CBCT and LD-CBCT measurements and the intraclass correlation coefficient (ICC) was calculated to assess intrarater reliability. Analyses were supported by Bland-Altman plots.

RESULTS

Volume measurements obtained using HD-CBCT were significantly higher than those obtained using LD-CBCT (p < 0.001). CCC was 0.975 (95% confidence interval [CI] = 0.956-0.986) indicating excellent agreement between the two modalities. Intrarater reliability between the two sets of LD-CBCT and HD-CBCT volume measurements was excellent (ICC = 0.998, 95%CI = 0.995-0.999 [HD-CBCT], ICC = 0.997, 95%CI = 0.992-0.998 [LD-CBCT]). CCC for tooth length measurements was 0.991 (95% CI = 0.983-0.995), indicating excellent agreement between HD-CBCT and LD-CBCT. Intrarater reliabilities between the two sets of tooth length measurements were also excellent for both methods (ICC = 0.998, 95%CI = 0.995-0.999 [HD-CBCT], ICC = 0.997, 95%CI = 0.992-0.998 [LD-CBCT]).

CONCLUSIONS

Within the limitations of this experimental setting, LD-CBCT is as valid as HD-CBCT for measuring tooth length. Regarding the volume differences, in vivo studies are required to determine their clinical relevance.

Tomographic diagnosis of alveolar bone coverage impact in orthodontic planning: cross-sectional study

INTRODUCTION

Alveolar bone coverage can be diagnosed through cone beam computed tomography (CBCT) and this information can prevent orthodontic tooth movement beyond the biological limit.

OBJECTIVE

This study evaluated the impact of the bone coverage (BC) diagnosis by CBCT in the orthodontists' planning.

METHODS

One hundred fifty-nine Brazilian orthodontists suggested treatment plans for six patients at two different times, using two sequential questionnaires. The first questionnaire consisted of extra and intra-oral photographs, one panoramic radiograph; one lateral cephalometric radiograph with Steiner and Tweed analysis, and the patient chief complaint. The second questionnaire included the same presentations of cases with tomographic images and the radiologist's report. The McNemar test assessed the difference between the first and the second treatment plans.

RESULTS

In all six cases, most participants changed the treatment plan after evaluating the CBCT images and the radiologist's report (93.7% in case 5, 78.6% in case 4, 74.2% in case 3, 69.8% in case 6, 66% in case 2 and 61% in case 1; p≤0.01).

CONCLUSION

The evaluation of bone coverage through CBCT images has a substantial impact on the orthodontic diagnosis and planning of the Brazilian orthodontists.

Effective doses of scout projections in maxillofacial cone beam computed tomography

OBJECTIVES

To assess the effective and organ/tissue equivalent radiation doses of different scout projection protocols in four CBCT units.

METHODS

Optically stimulated luminescence dosimeters (OSLD) were placed in reference anatomical locations in the head and neck segments of an anthropomorphic phantom representing an average adult male. Ten repeated exposures were obtained from each of the twelve scout projections studied, acquired from four maxillofacial cone beam computed tomography (CBCT) units (Midmark EIOS, 3D Accuitomo F170, Veraviewepocs 3D R100, and Veraview X800). The effective and organ/tissue equivalent doses were calculated for each protocol.

RESULTS

Effective doses ranged from 0.7 µSv (Accuitomo F170 60 × 60 mm-anterior maxilla) to 6.9 µSv (Midmark 50 × 50 mm-anterior maxilla). The highest organ/tissue equivalent doses were recorded for the oral mucosa and salivary glands; however, the thyroid was the highest contributor to the effective dose, followed by the salivary glands.

CONCLUSIONS

Despite some variability among CBCT machines and protocols, the acquisition of scout projections is a low-dose procedure. The use of scout projections to ensure an adequate position of the region of interest within the field of view is highly desirable as they contribute minimally to overall CBCT patient dose.

Comparison of the Accuracy and Efficiency of Two Dynamic Navigation System Workflow for Fiber-post Removal: Small versus Large Field-of-view Registration Workflows

INTRODUCTION

This study investigates the feasibility of a dynamic navigation system (DNS) small field of view workflow (DNS-SFOVw) for fiber-post removal and compares its accuracy and efficiency to the conventional large field of view workflow (DNS-LFOVw).

METHODS

Fifty-six extracted human maxillary molars were divided into DNS-SFOVw (n = 28) and DNS-LFOVw (n = 28). The palatal canal was restored with an intraradicular RelyX fiber post and luted with RelyX Unicem; a core buildup was used. Teeth were mounted in a 3D-printed surgical jaw. A preoperative cone-beam computed tomography (CBCT) scan was taken with a 40 × 40 mm FOV for the DNS-SFOVw and a single arch CBCT scan for the DNS-LFOVw. The drilling entry point, trajectory, angle, and depth were planned in the X-guide software. The DNS registration method for the DNS-SFOVw was virtual-based registration on teeth, and the marker point-based method was used for the DNS-LFOVw. The fiber posts were drilled out under DNS guidance. A postoperative CBCT scan was taken. Three-dimensional deviations, angular deflection, number of mishaps, registration, and total operation time were calculated.

RESULTS

The DNS-SFOVw was as accurate as DNS-LFOVw (P > .05). The DNS-LFOVw registration time was less than DNS-SFOVw (P < .05). There was no difference in the number of mishaps (P > .05). Both DNS-SFOVw and DNS-LFOVw were time-efficient, with DNS-LFOVw taking less total operational time (P < .05).

CONCLUSION

Within the limitations of this in-vitro study, the DNS-SFOVw was as accurate as the DNS-LFOVw for fiberpost removal. Both DNS-LFOVw and DNS-SFOVw were time-efficient in removing fiber-posts.

Metal artifact reduction tool and mA levels impact on the diagnosis of fracture extension in endodontically treated teeth using cone-beam CT

AIM

To evaluate the influence of different levels of metal artifact reduction (MAR) tool and milliamperage (mA) on the diagnosis of fracture extension in endodontically treated teeth using cone beam CT (CBCT).

MATERIALS AND METHODS

Ten maxillary premolars were endodontically treated and positioned in the empty sockets of a human maxilla covered with wax. CBCT acquisitions were performed using the Eagle Edge device (Dabi Atlante, Brazil) adjusted to 120 kVp, FOV of 4 × 6 cm, exposure time of 24 s and voxel size of 0.2 mm in 8 different conditions with different MAR (1, 2 and 3) and mA (3.2 and 6.3) levels. Crown-root fractures were simulated in the universal testing machine, and CBCT images were acquired again. Five radiologists evaluated the presence and extension of fractures with a 5-point scale. Statistical analysis was performed by analysis of variance, Tukey and Kappa test (α = 0.05).

RESULTS

Although different mA levels did not significantly (p > 0.05) affect the diagnosis values for fracture presence and extension, when evaluated the different levels of MAR, AUC and sensitivity showed significantly higher values (p < 0.05) for MAR 0 using 6.3 mA and kappa agreement showed significantly higher values (p < 0.05) for MAR 0 and 2 using 6.3 mA.

CONCLUSIONS

Although mA levels do not have a diagnostic effect when isolating the MAR level; in 6.3 mA, MAR 0 and 2 can positively influence the diagnosis of fracture extension in endodontically treated teeth using CBCT.

CLINICAL RELEVANCE

The isolate evaluation of dental fracture presence can overlook diagnostics error of its extension.

Trends in the Use of Weightbearing Computed Tomography

Background: This review aimed to critically appraise the most recent orthopedic literature around cone beam weightbearing computed tomography (WBCT), summarizing what evidence has been provided so far and identifying the main research trends in the area. Methods: This scoping review was performed on studies published between January 2013 and December 2023 on the Pubmed database. All studies (both clinical and nonclinical) in which WBCT had been used were critically analyzed to extract the aim (or aims) of the study, and the main findings related to the role of this imaging modality in the diagnostic pathway. Results: Out of 1759 studies, 129 were selected. One hundred five manuscripts (81%) dealt with elective orthopedic conditions. The majority of the analyses (88 studies; 84%) were performed on foot and ankle conditions, while 13 (12%) studies looked at knee pathologies. There was a progressive increase in the number of studies published over the years. Progressive Collapsing Foot Deformity (22 studies; 25%) and Hallux Valgus (19 studies; 21%) were frequent subjects. Twenty-four (19%) manuscripts dealt with traumatic conditions. A particular interest in syndesmotic injuries was documented (12 studies; 60%). Conclusions: In this review, we documented an increasing interest in clinical applications of weightbearing CT in the orthopedic field between 2013 and 2023. The majority of the analyses focused on conditions related to the foot and the ankle; however, we found several works investigating the value of WBCT on other joints (in particular, the knee).

Skeletal effects of posterior crossbite treatment with either quad helix or rapid maxillary expansion: a randomized controlled trial with 1-year follow-up

OBJECTIVES

To assess skeletal and dental effects and evaluate possible side effects of maxillary expansion with two different appliances, directly after expansion and 1 year postexpansion.

MATERIALS AND METHODS

Forty-two patients with unilateral posterior crossbite (mean 9.5 ± 0.9 years) were randomized to either rapid maxillary expansion (RME) banded on the deciduous second molars and bonded to the primary canines or slow expansion with quad helix (QH) on the permanent first molars. Cone-beam computed tomography records were taken at baseline, directly after correction of the posterior crossbite and at follow-up 1 year after expansion.

RESULTS

All patients were analyzed. RME opened the midpalatal suture more anteriorly and inferiorly (mean 4.1 mm) and less posteriorly and superiorly (mean 1.0 mm). No effect on midpalatal suture could be shown in the QH group after expansion, P < .001. Buccal bone width had significantly decreased (P < .001) in the QH group compared with the RME group. Buccal fenestrations and root resorption on the left first molar had a higher prevalence directly after expansion finished in the QH group (P = .0086, P = .013) but were not significant at 1-year follow-up (P = .11, P = .22).

CONCLUSIONS

Opening of the suture with RME was more anterior and inferior, and the QH did not open the midpalatal suture at all. More buccal bone loss and fenestrations were seen on the permanent first molar in patients treated with conventional QH than RME anchored to deciduous teeth.

Opportunistic investigation of vascular calcification using 3-dimensional dental imaging

Purpose

Given the growing use of cone-beam computed tomography (CBCT) scans, this study assessed radiation exposure from these scans in the context of national guidelines and recommended dose limits.

Materials and Methods

The current literature was reviewed to quantify the benefit of opportunistic diagnosis of carotid artery calcification relative to the potential risk of radiation-induced cancer.

Results

The average radiation from CBCT at its largest field of view and highest resolution possible amounts to a reasonable but still low ionizing radiation exposure. This exposure is comparable to 22 days of background radiation and is notably lower than the radiation exposure from medical CT scans. According to the risk assessment analysis, the risk of stroke events involving internal and external carotid artery calcification (CAC) was 202 and 67 per 100,000 individuals, respectively. In contrast, the estimated risk of radiation-induced cancer associated with CBCT was notably lower, at 0.6 per 100,000.

Conclusion

The present study advocates for a comprehensive assessment of CBCT scans encompassing the areas of the internal and external carotid arteries by a knowledgeable professional, given the potential advantages of early detection of vascular abnormalities. Dental professionals who take scans involving these areas need to be mindful of reporting these findings and refer patients to their primary care physician for further investigation.

Protocol for Diagnostic Test Accuracy Study: Evaluation of Cone Beam Computed Tomography (CBCT) in Prediction of Inferior Alveolar Nerve Injury as Compared to Orthopantomography (OPG) Secondary to Surgical Removal of Impacted Mandibular Third Molars

Introduction Impairment of the inferior alveolar/dental nerve (IAN) is a relatively uncommon complication after lower wisdom tooth removal. Studies report varying incidences of IAN injury, with dysesthesia being noted as particularly distressing and 0-0.9% cases extending for a long duration. Neurosensory disruptions can severely impact speech, chewing, swallowing, and social interactions, leading to chronic pain and a lower quality of life. It also poses a risk of inadvertent injuries during meals. Although orthopantomogram (OPG) is primarily used for diagnosis, but when the lower wisdom tooth and nerve are in close approximation, cone beam computed tomography (CBCT) is recommended, despite its higher cost and radiation exposure. A white paper on third molar management necessitates further research on CBCT's role, citing conflicting evidence. Further in a multicentric trial, the difference between the OPG versus CBCT group was not statistically significant due to the low incidence of IAN injuries. They have emphasized the need for more well-designed studies to reach a statistically significant conclusion by meta-analyses. Hence, this study aims to provide additional evidence. Methods It is a two-arm, parallel, diagnostic study design involving individuals between the ages of 18 and 50 years, requiring lower wisdom tooth removal that is closely approximated with the nerve. Eligible adults, based on the specified inclusion/exclusion criteria, will be recruited into the study; informed consent will be obtained; then assigned randomly to the OPG or CBCT group using a random computer-generated sequence. Extractions will be done under local anesthesia using a standard surgical protocol with odontectomy. Surgical variables will include the experience of the surgeon, amongst others. The outcome variables will be recorded using patient interviews (subjective) and objective examinations from day one up to six months after surgery. The primary outcome will comprise the number of patients reporting abnormal sensations post-surgery. Secondary outcomes will include objectively confirmed IAN injuries and permanent IAN injuries (>6 months). Results will be analyzed statistically to look for significance and possible risk factors associated with it. Results If a statistically significant result is obtained, then we can deliberately reduce CBCT referrals and reserve them only for high-risk cases, wherein the risk of IAN injury cannot be predicted by OPG alone. If the experience of the surgeon proves to be an important risk factor, then it can also help refer high-risk patients to surgeons with more experience. Conclusion If CBCT proves to be statistically superior to OPG in the prediction of nerve injury, then we will be able to avoid significant morbidity and improve the quality of life of such patients by either modifying the surgical steps or by choosing other conservative treatment modalities. Further, this may reduce unnecessary CBCT referrals, thus reducing radiation exposure, the cost to patients, and, in turn, national healthcare expenditure. Besides, CBCT is not available at all centers, so a lot of low-risk patients can be managed safely at primary health centers, thus reducing the urban patient load.

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.

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.

Influence of Examiner Experience on the Measurement of Bone-Loss by Low-Dose Cone-Beam Computed Tomography: An Ex Vivo Study

The aim of this study was to investigate the influence of examiner experience on measurements of bone-loss using high-dose (HD) and low-dose (LD) CBCT. Three diagnosticians with varying levels of CBCT interpretation experience measured bone-loss from CBCT scans of three cadaveric heads at 30 sites, conducting measurements twice. Between the first and second measurements, diagnostician 2 and diagnostician 3 received training in LD-CBCT diagnostics. The diagnosticians also classified the certainty of their measurements using a three-grade scale. The accuracy of bone-loss measurements was assessed using the absolute difference between observed and clinical measurements and compared among diagnosticians with different experience levels for both HD and LD-CBCT. At baseline, there was a significant difference in measurement accuracy between diagnostician 1 and diagnostician 2, and between diagnostician 1 and diagnostician 3, but not between diagnostician 2 and diagnostician 3. Training improved the accuracy of both HD-CBCT and LD-CBCT measurements in diagnostician 2, and of LD-CBCT measurements in diagnostician 3. Regarding measurement certainty, there was a significant difference among diagnosticians before training. Training enhanced the certainty for diagnosticians 2 and 3, with a significant improvement noted only for diagnostician 3. Examiner experience level significantly impacts the accuracy and certainty of bone-loss measurements using HD- and LD-CBCT.

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).

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 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.

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.