Limited Cone-beam Computed Tomography Research Articles

A hierarchical deep learning approach for diagnosing impacted canine-induced root resorption via cone-beam computed tomography

ObjectivesCanine-induced root resorption (CIRR) is caused by impacted canines and CBCT images have shown to be more accurate in diagnosing CIRR than panoramic and periapical radiographs with the reported AUCs being 0.95, 0.49, and 0.57, respectively. The aim of this study was to use deep learning to automatically evaluate the diagnosis of CIRR in maxillary incisors using CBCT images.MethodsA total of 50 cone beam computed tomography (CBCT) images and 176 incisors were selected for the present study. The maxillary incisors were manually segmented and labeled from the CBCT images by two independent radiologists as either healthy or affected by root resorption induced by the impacted canines. We used five different strategies for training the model: (A) classification using 3D ResNet50 (Baseline), (B) classification of the segmented masks using the outcome of a 3D U-Net pretrained on the 3D MNIST, (C) training a 3D U-Net for the segmentation task and use its outputs for classification, (D) pretraining a 3D U-Net for the segmentation and transfer of the model, and (E) pretraining a 3D U-Net for the segmentation and fine-tuning the model with only the model encoder. The segmentation models were evaluated using the mean intersection over union (mIoU) and Dice coefficient (DSC). The classification models were evaluated in terms of classification accuracy, precision, recall, and F1 score.ResultsThe segmentation model achieved a mean intersection over union (mIoU) of 0.641 and a DSC of 0.901, indicating good performance in segmenting the tooth structures from the CBCT images. For the main classification task of detecting CIRR, Model C (classification of the segmented masks using 3D ResNet) and Model E (pretraining on segmentation followed by fine-tuning for classification) performed the best, both achieving 82% classification accuracy and 0.62 F1-scores on the test set. These results demonstrate the effectiveness of the proposed hierarchical, data-efficient deep learning approaches in improving the accuracy of automated CIRR diagnosis from limited CBCT data compared to the 3D ResNet baseline model.ConclusionThe proposed approaches are effective at improving the accuracy of classification tasks and are helpful when the diagnosis is based on the volume and boundaries of an object. While the study demonstrated promising results, future studies with larger sample size are required to validate the effectiveness of the proposed method in enhancing the medical image classification tasks.

A Comparison between Saudi Dental Students' Knowledge of CBCT and Intraoral Radiographs: A Cross-Sectional Study

Intraoral radiography is integral to dental diagnosis while cone beam computed tomography (CBCT) provides enhanced 3D visualization. We aimed to assess and compare knowledge regarding CBCT and intraoral radiography among 386 Saudi dental undergraduates via a cross-sectional questionnaire. Nearly all participants successfully identified bitewing (99%), periapical (97%) and CBCT (98%) images, indicating strong familiarity. However, only 6% had clinically utilized CBCT versus 80% using intraoral radiography. Just 14% received CBCT training compared to 65% trained in intraoral radiography. Most appropriately recognized children as the most radiation-sensitive group (47%) and recommended limited CBCT (62%) and intraoral (37%) radiographs monthly per ALARA principles. Root canal treatment (44%) and implant planning (29%) were the most common CBCT referral indications. Key barriers to routine CBCT implementation included high costs (67%), difficulty (16%), and insufficient training (14%). Advantages perceived were reduced radiation (17%), rapid imaging (38%), and lack of film processing (24%). Results highlight excellent conceptual understanding but limited practical experience and training in CBCT compared to intraoral radiography among Saudi dental students. Targeted education programs integrating hands-on CBCT exposure with training in radiation safety and appropriate use are warranted to support optimal future clinical adoption.

Developing a universal and reliable temporomandibular joint reference system for quantifying morphological and positional changes.

This study aimed to provide a universal and reliable reference system quantifying temporomandibular joint (TMJ) morphological and positional changes. Large field-of-view (FOV) cone-beam computed tomography (CBCT) images (20 TMJs) from 10 preorthognathic surgery patients and limited FOV CBCT images (40 TMJs) from 20 splint therapy-treated patients with temporomandibular disorders were collected. TMJ-specific reference system including a TMJ horizontal reference plane (TMJHP) and a local coordinate system (TMJCS) was constructed with landmarks on cranial base. Its application for TMJ measurements and its spatial relationship to common Frankfort horizontal plane (FHP) and maxillofacial coordinate system (MFCS) were evaluated. Five relevant landmarks were selected to optimally construct TMJ-specific reference system. General parallelism between TMJHP and FHP was demonstrated by minimal angular and constant distance deviation (1.714 ± 0.811º; 2.925 ± 0.817 mm). Additionally, tiny axial orientational deviations (0.181 ± 6.805º) suggested TMJCS rivaled MFCS. Moreover, small deviations in orientations and distances (1.232 ± 0.609º; 0.310 ± 0.202 mm) indicated considerable reliability for TMJCS construction, with intraclass correlation coefficients (ICCs) ranging from 0.999 to 1.000. Lastly, slight discrepancies in translations and rotations revealed high reliability for condylar positional and morphological measurements (ICC, 0.918-0.999). TMJ-specific reference system was merely tested in two representative FOVs. This study provides a universal and reliable reference system for TMJ assessment that is applicable to both limited and large FOV CBCT. It would improve comparability among diverse studies and enable comprehensive evaluations of TMJ positional and morphological changes during TMJ-related treatment follow-up such as splint therapy and disease progression.

Modular Neural Networks for Osteoporosis Detection in Mandibular Cone-Beam Computed Tomography Scans.

In this technical note, we examine the capabilities of deep convolutional neural networks (DCNNs) for diagnosing osteoporosis through cone-beam computed tomography (CBCT) scans of the mandible. The evaluation was conducted using 188 patients' mandibular CBCT images utilizing DCNN models built on the ResNet-101 framework. We adopted a segmented three-phase method to assess osteoporosis. Stage 1 focused on mandibular bone slice identification, Stage 2 pinpointed the coordinates for mandibular bone cross-sectional views, and Stage 3 computed the mandibular bone's thickness, highlighting osteoporotic variances. The procedure, built using ResNet-101 networks, showcased efficacy in osteoporosis detection using CBCT scans: Stage 1 achieved a remarkable 98.85% training accuracy, Stage 2 minimized L1 loss to a mere 1.02 pixels, and the last stage's bone thickness computation algorithm reported a mean squared error of 0.8377. These findings underline the significant potential of AI in osteoporosis identification and its promise for enhanced medical care. The compartmentalized method endorses a sturdier DCNN training and heightened model transparency. Moreover, the outcomes illustrate the efficacy of a modular transfer learning method for osteoporosis detection, even when relying on limited mandibular CBCT datasets. The methodology given is accompanied by the source code available on GitLab.

Assessment of condylar positional changes in severe skeletal class II malocclusion after surgical-orthodontic treatment.

This study aimed to determine the positional changes in the condyle in the temporomandibular joint (TMJ) of severe skeletal class II malocclusion patients treated with surgical-orthodontics. The measurements of TMJ space in 97 severe skeletal class II malocclusion patients (20 males, 77 females, mean age, 24.8 years, mean ANB = 7.41°) were assessed using limited cone-beam computed tomography (LCBCT) images acquired before orthodontics (T0) and 12 months after surgery (T1). 3D remodeling of the TMJ and measurements of the anterior space (AS), superior space (SS), and posterior space (PS) were performed to determine the position of the condyle for each joint. All data were analyzed by t test, correlation analysis, and Pearson correlation coefficient. The mean AS, SS, and PS values after the therapy changed from 1.684 to 1.680 mm (0.24%), 3.086 to 2.748 mm (10.968%), and 2.873 to 2.155 mm (24.985%), respectively. The decreases in SS and PS were statistically significant. Positive correlations were found in the mean AS, SS, and PS values between the right and left sides. The combination of orthodontic and surgical treatment makes the condyle move counterclockwise in the TMJ in severe skeletal class II patients. Studies of temporomandibular joint (TMJ) intervals changes in patients with severe skeletal class II after sagittal split ramus osteotomy (SSRO) are limited. The postoperative joint remodeling, resorption, and related complications remain unstudied.

English

BACKGROUND Local response of the bone surrounding the apex of the tooth as a result of pulp necrosis or destruction of the periapical tissues caused by significant periodontal disease is known as a periapical inflammatory lesion. Intraoral radiography is the most commonly used technique but has limitations in representing only 2- dimensional images. CBCT was created primarily to provide 3-dimensional maxillary skeletal images and a smaller and mid field of view (FOV) have a higher spatial resolution and improved diagnostic potential. The intention of this study was to compare and evaluate the results of limited view CBCT and DDI in the diagnosis of periapical pathology. METHODS In this study, a total of 25 patients who visited the oral medicine department with clinical and or radiographic findings were included. Periapical lesions were assessed using a cone-beam CT periapical index (CBCTPAI) scoring system in both direct digital imaging (DDI) radiographs and CBCT images. RESULTS Periapical lesions were found to be more prevalent in 30 - 39 years (40 %) with a male predilection (64 %) and maxillary anterior (36 %) more commonly affected. Wilcoxon signed-rank test performed to assess the mean difference between the two imaging modalities revealed a P < 0.001 and was statistically significant. CONCLUSIONS This study highlights the role of CBCT in diagnosing periapical lesions which can be missed or misdiagnosed on DDI. KEY WORDS Cone Beam Computed Tomography (CBCT); Direct Digital Imaging (DDI); Periapical Lesions

Comparative analysis of the accuracy of periapical radiography and cone-beam computed tomography for diagnosing complex endodontic pathoses using a gold standard reference - A prospective clinical study.

To compare the diagnostic accuracy of periapical radiography (PR) and cone-beam computed tomography (CBCT) for detecting pathoses of endodontic origin using the gold standard of direct surgical visualization. Seventy-four patients (112 teeth) underwent radiographic examination by periapical radiography and CBCT. The presence of periapical lesions, root perforations and their locations, root fractures, different types of external root resorptive defects, apicomarginal bone defects, through and through bone defects, buccal bone status and proximity of root apices and lesions to vital anatomical structures were assessed. These same parameters were assessed intraoperatively by direct surgical visualization which served as the gold standard reference for the radiographic assessments. Sensitivity, specificity, positive predictive values, negative predictive values were determined for comparison of diagnostic accuracy between two modalities. There were no significant differences between the two imaging modalities for root resorptive defects and root fractures. However, CBCT accurately detected periapical lesions, root perforations, apicomarginal bone defects and through and through bone defects. The overall accuracy of CBCT varied from 91% to 96% in detecting dehiscence and fenestration of buccal cortical plates. Overall, CBCT had a higher diagnostic accuracy in complex endodontic pathoses compared to PR. Nevertheless, CBCT failed to diagnose apicomarginal bone defects in 33% teeth. In evaluating the status of buccal cortical plate from CBCT images, observers could detect absence of bone better than its presence. Thus, limited FOV CBCT should be considered for selective cases where periapical radiography has diagnostic ambiguity.

Deep Active Learning for Automatic Segmentation of Maxillary Sinus Lesions Using a Convolutional Neural Network.

The aim of this study was to segment the maxillary sinus into the maxillary bone, air, and lesion, and to evaluate its accuracy by comparing and analyzing the results performed by the experts. We randomly selected 83 cases of deep active learning. Our active learning framework consists of three steps. This framework adds new volumes per step to improve the performance of the model with limited training datasets, while inferring automatically using the model trained in the previous step. We determined the effect of active learning on cone-beam computed tomography (CBCT) volumes of dental with our customized 3D nnU-Net in all three steps. The dice similarity coefficients (DSCs) at each stage of air were 0.920 ± 0.17, 0.925 ± 0.16, and 0.930 ± 0.16, respectively. The DSCs at each stage of the lesion were 0.770 ± 0.18, 0.750 ± 0.19, and 0.760 ± 0.18, respectively. The time consumed by the convolutional neural network (CNN) assisted and manually modified segmentation decreased by approximately 493.2 s for 30 scans in the second step, and by approximately 362.7 s for 76 scans in the last step. In conclusion, this study demonstrates that a deep active learning framework can alleviate annotation efforts and costs by efficiently training on limited CBCT datasets.

Web-based educational programme for temporomandibular joint assessment with cone-beam computed tomography.

To develop and evaluate an educational web-based programme for temporomandibular joint (TMJ) assessment using cone-beam computed tomography (CBCT). A web-based educational programme was designed for TMJ assessment using CBCT images. Fifteen CBCT cases of the TMJ (three-dimensional reconstructed volumes) and an assessment module based on image analysis criteria in the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) were added to the programme. Thirty-six undergraduate dental students were invited to test the programme by assessing all cases twice: before and after 2months of training. Participants submitted written subjective evaluations of the programme. The web-based programme can be accessed on Malmö University webpage (www.cbct-tmj.mau.se). Despite limited CBCT learning in their undergraduate training and not using the programme in the 2-month interval, the students were able to correctly diagnose 80% of the cases at the second assessment. Their diagnoses, however, did not differ significantly from the first assessment. Overall, the students were satisfied with the programme and considered it user-friendly. The web-based educational programme that was developed in the present study and tested by dental students could be a useful educational tool for TMJ assessment using CBCT.

Role of Computed Tomography Scan in Dental Trauma: A Cross-Sectional Study.

Background:Dental trauma is caused by fracture(s) in the vertical plane and the horizontal plane of roots. The objective of this study is to perform multiple diagnostic modalities for the diagnosis of horizontal root fracture(s) of the tooth.Methods:A total of 250 patients with dental complaints were subjected to intraoral radiography, multidetector helical computed tomography (MDHCT), and limited cone beam computed tomography (LCBCT). The suspected tooth was extracted, visually inspected, and subjected to microcomputed tomography (micro-CT). Images were observed in the lightbox, and a fracture was considered if it had been directly visualized as radiolucent line traversing tooth root. Wilcoxon test/Tukey post hoc test was performed at 99% of confidence level.Results:With respect to visual inspection, for LCBCT, intraoral radiography, MDHCT, and micro-CT, sensitivities were 0.988, 0.972, 0.967, and 0.979; accuracies were 0.956, 0.785, 0.905, and 0.888; false-positive values were 5, 21, 12, and 11; and false-negative values were 3, 24, 3, and 11, respectively. The area of the image visible at one time was in the order of treatment without radiography < intraoral radiography < MDHCT < micro-CT < LCBCT.Conclusion:The LCBCT had the highest sensitivity and accuracy for diagnosis of horizontal tooth root fracture(s).Level of Evidence:I.Trial Registry:researchregistry3647, dated December 31, 2016 (www.researchregistry.com).

Accuracy of Cone-beam Computed Tomographic Image Interpretation by Endodontists and Endodontic Residents

IntroductionLimited field cone-beam computed tomography (CBCT) imaging has become a modality frequently used by endodontists to evaluate the teeth and surrounding tissues of their patients. Accurate image interpretation is vital to obtain needed treatment information as well as to discern coincidental findings that could be present. The goal of this study was to determine the accuracy of CBCT volume interpretation when performed by endodontists and endodontic residents. MethodsEighteen deidentified limited field CBCT scans were obtained and evaluated by an oral and maxillofacial radiologist and an endodontist experienced in reading CBCT images. Their collective findings were combined as the “gold standard” of interpretation for this investigation. Using standard CBCT software, 4 practicing endodontists and 5 second-year endodontic residents evaluated each scan and recorded any notable findings and whether or not each scan warranted referral to a radiology specialist. Their interpretations were then compared with the gold standard to determine accuracy and any significant differences among the groups. ResultsThe overall accuracy was 58.3% for endodontists and 64.3% for residents. Paired t tests showed no statistically significant differences in accuracy between the 2 groups for findings in teeth or in bone, but residents were significantly better for maxillary sinus findings. Endodontists agreed with the gold standard 38.9% of the time and residents 49.8% of the time on necessity of referral. The Cohen kappa coefficient showed moderate agreement between the groups. ConclusionsEndodontists and residents had similar accuracy in CBCT scan evaluation. More training and experience are warranted for both groups in order to maximize image assessment accuracy.

Impact of cone beam computed tomography (CBCT) on diagnostic thinking in endodontics of posterior teeth: A before- after study

ObjectivesThe aim of this study was to evaluate the impact of limited volume CBCT upon diagnosis as part of endodontic management of posterior teeth. The null hypothesis that CBCT does not make any difference in endodontic diagnosis was tested. MethodsA single-centre “before-after” study was conducted in a secondary healthcare establishment. Eligible patients were all adults aged 18 years or over who were referred to a specialist endodontic unit. Further inclusion criteria were that the cases were either re-treatment or de novo root canal treatment where the anatomy was judged to be complex. Exclusion criteria included vulnerable groups and de novo endodontic treatment with uncomplicated root canal anatomy. As well as a full history and clinical examination, a high quality colour photographic intraoral image, two paralleling technique periapical radiographs and limited volume CBCT examination were carried out for each patient. All components, except the CBCT dataset, were combined into a Powerpoint presentation and assessed by 4 observers. A questionnaire was designed for the observers as part of the study. ResultsCBCT information only changed the radiological findings and the final diagnosis in a minority of cases. There was no clear evidence that CBCT increases the confidence of observers or that CBCT was helpful in making a diagnosis. ConclusionsRoutine use of CBCT cannot not be justified on the basis of a change in diagnosis and carefully selected use is appropriate. Clinical significanceCBCT is being increasingly used in the field of endodontics. The benefits gained from the use of CBCT must be carefully balanced against the increased radiation dosage. Determination of selection criteria for the use of CBCT in endodontics is, therefore, essential.

Prevalence of Apical Periodontitis in Endodontically Treated Premolars and Molars with Untreated Canal: A Cone-beam Computed Tomography Study

IntroductionThe purpose of this retrospective cohort study was to evaluate the incidence of missed canals in endodontically treated teeth in the Greater Philadelphia area patient population and to evaluate the effect of untreated canals on endodontic outcome. MethodsA total of 1397 cone-beam computed tomography (CBCT) volumes taken from January 2013 to July 2015 were investigated. Limited view CBCT images were taken with Kodak 9000 3D System field of view at voxel size, 76 μm or Morita Veraviewpocs 3D F40 field of view at voxel size, 125 μm. All root canal–treated premolars and molars were included in the study. Unfilled canals appearing from cementoenamel junction to apex including splitting from a main canal at coronal, mid, or apical third were defined as missed-untreated canal. A periapical lesion was diagnosed when disruption of the lamina dura was detected and the low density area associated with the radiographic apex was at least twice the width of the periodontal ligament space. ResultsThe overall incidence of missed canals was 23.04%. The incidence of missed canals per tooth was highest in tooth #14 at 46.5% and tooth #3 at 41.3%. The incidence of missed canals was highest in the upper molars at 40.1% and lowest in the upper premolars at 9.5%. There was a significant difference in lesion prevalence when a canal was missed-untreated (P < .05). Teeth with a missed canal were 4.38 times more likely to be associated with a lesion. ConclusionsLimited field-of-view CBCT should be examined before any endodontic retreatment to identify missed canals. This knowledge would not only help clinicians to locate missed canals clinically but would also help in deciding the surgical approach.

Motion-compensated cone beam computed tomography using a conjugate gradient least-squares algorithm and electrical impedance tomography imaging motion data.

Cone beam computed tomography (CBCT) is an imaging modality that has been used in image-guided radiation therapy (IGRT). For applications such as lung radiation therapy, CBCT images are greatly affected by the motion artefacts. This is mainly due to low temporal resolution of CBCT. Recently, a dual modality of electrical impedance tomography (EIT) and CBCT has been proposed, in which the high temporal resolution EIT imaging system provides motion data to a motion-compensated algebraic reconstruction technique (ART)-based CBCT reconstruction software. High computational time associated with ART and indeed other variations of ART make it less practical for real applications. This paper develops a motion-compensated conjugate gradient least-squares (CGLS) algorithm for CBCT. A motion-compensated CGLS offers several advantages over ART-based methods, including possibilities for explicit regularization, rapid convergence and parallel computations. This paper for the first time demonstrates motion-compensated CBCT reconstruction using CGLS and reconstruction results are shown in limited data CBCT considering only a quarter of the full dataset. The proposed algorithm is tested using simulated motion data in generic motion-compensated CBCT as well as measured EIT data in dual EIT-CBCT imaging.

A Reference Line on Temporomandibular Joint MRI

The aim of this study was to establish a reference line and the 12 o'clock position on sagittal MRI images of the temporomandibular joint (TMJ) for close observation of early changes in disk position. The study included 106 joints of 53 consecutive male and female patients (mean age 13.3 years) with available MRI and limited cone-beam computed tomography (LCBCT) images, from a pool of postorthodontic patients who had finished phase I or phase II orthodontic treatment between March 2006 and March 2008 in a private orthodontic office. High-resolution (0.1 pixel) LCBCT images taken in natural head position in the same time period and adjusted to the same magnification were superimposed on corresponding MRI images. The true horizontal line (THL) determined by natural head position on the LCBCT image was transferred to the MRI image. A clinically easy-to-use reference line (RL) approximating THL was drawn by connecting two readily locatable anatomical landmarks, the most inferior point of the articular eminence and the center of the auditory canal, and correspondence between THL and RL was assessed. The mean angle formed by THL and RL on the MRI images of the TMJs studied was 2.2° (SD 2.8°) clockwise around the center of the auditory canal, and the angulations of THL and RL on MRI images of the TMJs studied demonstrated a high positive correlation (r = 0.84). THL can be established directly on MRI images using the THL-RL angle obtained by this study in patients without advanced disk displacement resulting in bony changes of the joint. The deepest point on the glenoid fossa that meets the THL can be used as the 12 o'clock position for evaluation of incipient disk position change.

Intraoperative Endodontic Applications of Cone-Beam Computed Tomography

IntroductionThe use of cone-beam computed tomography (CBCT) in endodontics for diagnosis, treatment planning, and follow-up has been extensively reported in the literature. Compared with the traditional spiral computed tomography, high-resolution limited CBCT results in a fraction of the effective absorbed dose of radiation. However, it should be prescribed only after weighing the cost of radiation exposure with the benefit of the diagnostic information that can be obtained from the scan. MethodsThe purpose of this article is to discuss the application and advantages of intraoperative CBCT in endodontics, while reducing radiation exposure during complex endodontic procedures. ResultsIn cases of increased difficulty or intraoperative complications such as complex anatomy, dystrophic calcifications, root resorptions, perforations, and root fractures, it is prudent to consider the use of CBCT with its inherent diagnostic value and limited radiation exposure. ConclusionsThe benefits of the added diagnostic information provided by intraoperative CBCT images in select cases justify the risk associated with the limited level of radiation exposure.

Endodontic Working Length Measurement with Preexisting Cone-Beam Computed Tomography Scanning: A Prospective, Controlled Clinical Study

IntroductionThe determination of root canal length is a significant outcome predictor for endodontic treatments. The aim of this prospective, controlled clinical study was to analyze endodontic working length measurements in preexisting cone-beam computed tomography (CBCT) scans and to compare them with clinical root canal length determination by using an electronic apex locator (EAL). MethodsAll included patients had received a CBCT scan independent of the present study and needed root canal treatment of at least 1 anterior tooth visible in the field of view. Clinically, the root canal length was measured with an EAL by an endodontist. This measurement was compared with the root canal length as measured on vestibulo-oral and mesiodistal CBCT sections by an examiner not involved in the endodontic treatment. The CBCT measurements were repeated once for analysis of intrarater reliability. ResultsForty anterior teeth in 30 patients (13 women and 17 men; average age, 44 years; range, 18–80 years) were included in this investigation. The Pearson correlation coefficient (r) comparing the root canal length measurements by using CBCT and EAL was 0.97. In addition, high intrarater reliability for the CBCT measurements was found (r = 0.99). ConclusionsThis prospective, controlled clinical study showed that limited CBCT scans can be used for endodontic working length measurements. Future studies are needed to evaluate whether preexisting CBCT scans could replace initial periapical radiographs and working length periapical radiographs.

A comparison of cone beam computed tomography and conventional periapical radiography at detecting peri‐implant bone defects

To compare the diagnostic accuracy of conventional periapical radiography and cone beam computed tomography (CBCT) at detecting peri-implant bone defects. Implants were placed in fresh bovine ribs in osteotomy sites of varying diameter (five with no peri-implant space, five with a 0.35 mm space, five with a 0.675 mm space) and imaged using (i) digital long cone periapical radiographs (LCPAs), (ii) limited volume CBCT using 3D Accuitomo 80(®) and (iii) large volume CBCT using i-CAT Next Generation(®). Images from each were randomly presented to nine examiners on two occasions. Confidence in diagnosing the presence or absence of a peri-implant radiolucency was recorded on a five-point scale. Receiver Operating Characteristic (ROC) analysis and Kappa tests were performed. Digital LCPAs were better at diagnosing a peri-implant bone defect when the peri-implant space was 0.35 mm (P < 0.02). As the peri-implant space increased to 0.675 mm, there was no significant difference in diagnostic accuracy between the three imaging methods. Sensitivity of LCPAs (100) and Accuitomo (97.8) was better than i-CAT (64.4) (P < 0.02). LCPAs and i-CAT had significantly better specificity and positive predictive value than Accuitomo. The negative predictive value of LCPA was significantly better than i-CAT. LCPAs showed better intra-examiner and inter-examiner agreement than CBCT. Within the limitations of this study, LCPAs are a reliable and valid method of detecting circumferential peri-implant bone defects and performed significantly better than CBCT.

Does a Combination of Two Radiographs Increase Accuracy in Detecting Acid-induced Periapical Lesions and Does It Approach the Accuracy of Cone-Beam Computed Tomography Scanning?

Introduction The purpose of this study was to determine whether the use of a combination of 2 images (storage phosphor plates [SPPs] and F-speed films [Eastman Kodak, Rochester, NY]) with a 10° difference in horizontal beam angulation resulted in better detectability of chemically created periapical defects than when only 1 image was used and whether a detectability as good as that achieved by limited cone-beam computed tomography (LCBCT) scanning could be achieved. Methods Lesions were created by 1, 1.5, and 2 hours of acid application apical to extracted teeth in jaw specimens. After repositioning, teeth were radiographed with Accu-I-Tomo LCBCT, Digora Optime SPP system, and F-speed films. The SPPs and films were exposed at 0° and 10° horizontal angulations. The diagnostic accuracy (Az) was compared using 2-way analysis of variance; pair-wise comparisons were performed using the post hoc t test. Kappa was used to measure interobserver agreement. Results A combination of 2 exposures with a 10° difference in horizontal angulation caused an increase, although not statistically significant, in the accuracy of both films and SPPs for all acid durations ( P > .05) compared with when only 1 exposure was used. The accuracy did not approach that of LCBCT. Conclusions Using a combination of 2 exposures instead of 1 did not significantly increase the accuracy in detecting acid-induced lesions at the apices of single-rooted premolars. The accuracy of LCBCT was superior.

Precision of Endodontic Working Length Measurements: A Pilot Investigation Comparing Cone-Beam Computed Tomography Scanning with Standard Measurement Techniques

Introduction The objective of this pilot investigation was to evaluate the utility and precision of already existing limited cone-beam computed tomography (CBCT) scans in measuring the endodontic working length, and to compare it with standard clinical procedures. Methods Three patients referred to the department received limited CBCT scans for diagnostics and preoperative treatment planning of cystic jawbone pathologies. Part of the therapy consisted of root canal treatments before surgical enucleation of the lesion. For the determination of the working length, the root canal length was measured with an electronic apex locator (EAL) by the endodontist. This measurement was compared with the root canal length as measured on the respective CBCT scans by an examiner not involved in the endodontic treatment. The interrater agreement between the two examiners was analyzed to determine the feasibility of this technique. Results In the three included patients, 9 teeth with a total of 10 root canals were treated. For these canals, a strong correlation was found between the endodontic working length as measured in the CBCT images and the EAL measurements (Pearson correlation coefficient ranging from 0.904 to 0.968). Conclusions Based on the present findings, an already existing CBCT scan of teeth to be endodontically treated can be useful to determine the endodontic working length in combination with clinical measurements such as the EAL. Future prospective studies should evaluate if and when intraoral radiography for measuring the length of root canals can be avoided when CBCT images are available.