Positioning errors and quality assessment in panoramic radiography

Factors influencing submandibular fossa visibility on panoramic images: a comparative CBCT study

OBJECTIVE

This study aimed to investigate the variables affecting the visibility of the submandibular fossa (SF) on panoramic images, including SF depth and types, age, gender, presence or absence of tooth, location of mandibular canal, and alveolar bone thicknesses.

METHODS

Cone beam computed tomography (CBCT) images and conventional panoramic images of 150 patients were analyzed retrospectively. The visibility of the SF on panoramic images was compared with its depth and adjacent alveolar bone thicknesses on CBCT. Predictive variables affecting the SF visibility were identified, and binary logistic regression analysis was performed.

RESULTS

Based on CBCT measurements, the SF depth was ≥ 2 mm in 65% of the hemi-mandibles with radiolucent area (26.7%). A significant difference was observed between the SF visibility on panoramic images and its depth, and the lingual cortical bone thickness as measured on CBCT. When the SF was visible and not, the mean SF depth was 2.24 ± 0.97 mm and 1.6 ± 0.8 mm, and lingual cortical bone thickness was 1.27 ± 0.47 mm and 1.53 ± 0.49, respectively. Regression analysis revealed significant associations between SF visibility and gender (Odds ratio (OR) = 3.28, 95% confidence interval (CI): 1.77-6.09), age (OR = 0.96, 95% CI: 0.94-0.98), SF depth (OR = 2.01, 95% CI: 1.43-2.81), and lingual cortical bone thickness (OR = 2.02, 95% CI: 1.30-3.16).

CONCLUSIONS

A prominent radiolucent SF on panoramic images indicates a deeper fossa and thinner lingual cortical bone, necessitating caution by clinicians during surgical planning.

How does the direction of region of interest selection affect the fractal dimension?

OBJECTIVES

Introduction Fractal analysis (FA) is a computational method used to quantify the complex trabecular structure of bone. While FA has been widely applied in dentistry, there are challenges in standardizing the technique due to factors such as image resolution, region of interest (ROI) selection, and image processing. This study aimed to investigate the impact of the direction of ROI selection (DROIS) on fractal dimension (FD) calculations.

METHODS

Panoramic radiographs of 226 individuals aged 20-35 years were analyzed. ROIs were selected on the mandibular condyle, angular region, and mental region, and oriented at 0°, 22.5°, 45°, and 67.5° angles. FD was calculated using the box-counting method in ImageJ. The Friedman test and Wilcoxon signed-rank test were used for statistical analysis.

RESULTS

The FD values differed significantly between the angled ROI groups in all three regions (Friedman test, p < 0.0001). Pairwise comparisons showed significant differences in FD between most ROI orientations, except between 22.5° and 67.5° in the angular region.

CONCLUSIONS

DROIS is an important factor that should be considered in FA studies to ensure reliable and reproducible FD values. Appropriate methodological choices can help account for the influence of DROIS on FD calculations..

Diagnostic accuracy of periapical radiography and panoramic radiography in the detection of apical periodontitis: a systematic review and meta-analysis

OBJECTIVE

Apical periodontitis (AP) is one of the most common pathologies of the oral cavity. An early and accurate diagnosis of AP lesions is crucial for proper management and planning of endodontic treatments. This study investigated the diagnostic accuracy of periapical radiography (PR) and panoramic radiography (PAN) in the detection of clinically/surgically/histopathologically confirmed AP lesions.

METHOD

A systematic literature review was conducted in accordance with the PRISMA guidelines. The search strategy was limited to English language articles via PubMed, Embase and Web of Science databases up to June 30, 2023. Such articles provided diagnostic accuracy values of PR and/or PAN in the detection of AP lesions or alternatively data needed to calculate them.

RESULTS

Twelve studies met inclusion criteria and were considered for the analysis. The average value of diagnostic accuracy in assessing AP lesions was 71% for PR and 66% for PAN. According to different accuracy for specific anatomical areas, it is recommended to use PR in the analysis of AP lesions located in the upper arch and lower incisor area, whereas lower premolar and molar areas may be investigated with the same accuracy with PR or PAN.

CONCLUSIONS

Two-dimensional imaging must be considered the first-level examination for the diagnosis of AP lesions. PR had an overall slightly higher diagnostic accuracy than PAN. Evidence from this review provided a useful tool to support radiologists and dentists in their decision-making when inflammatory periapical bone lesions are suspected to achieve the best clinical outcome for patients, improving the quality of clinical practice.

Deep learning to assess bone quality from panoramic radiographs: the feasibility of clinical application through comparison with an implant surgeon and cone-beam computed tomography

PURPOSE

Bone quality is one of the most important clinical factors for the primary stability and successful osseointegration of dental implants. This preliminary pilot study aimed to evaluate the clinical applicability of deep learning (DL) for assessing bone quality using panoramic (PA) radiographs compared with an implant surgeon's subjective tactile sense and cone-beam computed tomography (CBCT) values.

METHODS

In total, PA images of 2,270 edentulous sites for implant placement were selected, and the corresponding CBCT relative gray value measurements and bone quality classification were performed using 3-dimensional dental image analysis software. Based on the pre-trained and fine-tuned ResNet-50 architecture, the bone quality classification of PA images was classified into 4 levels, from D1 to D4, and Spearman correlation analyses were performed with the implant surgeon's tactile sense and CBCT values.

RESULTS

The classification accuracy of DL was evaluated using a test dataset comprising 454 cropped PA images, and it achieved an area under the receiving characteristic curve of 0.762 (95% confidence interval [CI], 0.714-0.810). Spearman correlation analysis of bone quality showed significant positive correlations with the CBCT classification (r=0.702; 95% CI, 0.651-0.747; P<0.001) and the surgeon's tactile sense (r=0.658; 95% CI, 0.600-0.708, P<0.001) versus the DL classification.

CONCLUSIONS

DL classification using PA images showed a significant and consistent correlation with CBCT classification and the surgeon's tactile sense in classifying the bone quality at the implant placement site. Further research based on high-quality quantitative datasets is essential to increase the reliability and validity of this method for actual clinical applications.

Radiation safety of dentomaxillofacial radiology in Finland: Reported abnormal irradiation-related incidents during 2012-2022

INTRODUCTION

This study evaluates adverse events (AEs) in dentomaxillofacial radiology (DMFR) in Finland, including their quantity, nature, and outcomes. It also compares reporting activity between public and private healthcare organizations, as they share same legal obligations to report AEs. Two-thirds of dental images are taken in public, the rest in private healthcare.

METHODS

In Finland, radiation-related AEs are reported to the Radiation and Nuclear Safety Authority (STUK). We categorized DMFR-related AEs by nature, outcome, and imaging modality. We also submitted a questionnaire to STUK to gather information on their observations and remarks made during inspections of establishments providing dental imaging services.

RESULTS

During 2012-2022, STUK received reports of 1343 DMFR-related AEs, mostly causing patient harm (92.9%) leading almost always to excessive radiation doses (99.7%). Private healthcare reported most AEs (65.2%), with municipal institutions reporting the remainder (34.8%). Intraoral-related AEs (20.0%) slightly outnumbered panoramic-related ones (18.7%), but the majority (56.7%) didn't specify the imaging modality. CBCT-related incidents were least reported (4.5%). During STUK's inspections, remarks mostly concerned deficiencies in practical quality assurance (31.3%) or technical quality assurance (32.9%).

CONCLUSION

DMFR-related AEs may be underreported despite legal obligations, with most stemming from human error, highlighting the need to enhance patient safety culture. There's a notable reporting gap between private and public healthcare providers relative to the number of dental radiographs conducted. Organizational deficiencies in practical and technical quality assurance underscore the importance of ongoing education, as well as monitoring by STUK.

IMPLICATIONS FOR PRACTICE

Enhancing patient safety culture in dentistry, including dentomaxillofacial radiology, demands customized multiprofessional development, as unaltered patient safety procedures from medicine and secondary care may not align with dentistry's requirements.

Effect of using different strips on reducing the most common error in panoramic imaging: A randomised controlled trial on palatoglossal air space shadow

INTRODUCTION

Panoramic radiography quality can be impaired by some errors such as positioning errors. Palatoglossal air space shadow error is one of the most common positioning errors and it is due to the tongue not sticking to the roof of the palate. Techniques used to deal with this error might help prevent unnecessary radiation to patients and save them time and money. The study aimed to investigate the effects of using celluloid matrix and edible tapes (fruit leather and chewing gum) on reducing the palatoglossal air space shadow error in panoramic imaging.

METHODS

In our study, 270 patients referred to the Department of Radiology were randomised into three groups: a control group, a celluloid matrix group and an edible tapes group. Before panoramic imaging, all patients were instructed to adhere their tongues to the roof of their mouths, with the distinction that for the celluloid matrix and edible tapes groups, patients were asked to place celluloid tapes, fruit leathers, or chewing gums on their tongues before doing so. The routine imaging process was then performed, and the results were compared across groups to evaluate the incidence of palatoglossal air space shadow error.

RESULTS

The number of error-free images in each fruit leather, chewing gum and celluloid tape group were significantly higher than the control group (all cases P < 0.05). The chances of error-free images in the fruit leather groups were the highest (9.57 times). The age (P = 0.136) and gender (P = 0.272) of patients had no significant effect on the results of interventions.

CONCLUSION

The application of fruit leathers, chewing gums and celluloid tapes reduced the palatoglossal air space shadow error of panoramic imaging.

Panoramic imaging errors in machine learning model development: a systematic review

OBJECTIVES

To investigate the management of imaging errors from panoramic radiography (PAN) datasets used in the development of machine learning (ML) models.

METHODS

This systematic literature followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and used three databases. Keywords were selected from relevant literature.

ELIGIBILITY CRITERIA

PAN studies that used ML models and mentioned image quality concerns.

RESULTS

Out of 400 articles, 41 papers satisfied the inclusion criteria. All the studies used ML models, with 35 papers using deep learning (DL) models. PAN quality assessment was approached in 3 ways: acknowledgement and acceptance of imaging errors in the ML model, removal of low-quality radiographs from the dataset before building the model, and application of image enhancement methods prior to model development. The criteria for determining PAN image quality varied widely across studies and were prone to bias.

CONCLUSIONS

This study revealed significant inconsistencies in the management of PAN imaging errors in ML research. However, most studies agree that such errors are detrimental when building ML models. More research is needed to understand the impact of low-quality inputs on model performance. Prospective studies may streamline image quality assessment by leveraging DL models, which excel at pattern recognition tasks.

The intra- and inter-rater reproducibility of bone level measurements at strategic mini-implants using dental panoramic radiography

OBJECTIVES

This experimental study focused on the intra- and inter-rater reproducibility of vertical bone level (VBL) measurements at strategic mini-implants (MI) using digital panoramic radiographs (PR).

STUDY DESIGN

VBLs of 152 MIs for removable partial denture stabilization at 50 randomly chosen PRs from a clinical trial were digitally evaluated by three ratters. Rater deviations exceeding 0.5 mm were re-examined. The intra-class correlation coefficient (ICC) was applied to estimate reliability. The smallest detectable change (SDC) was interrelated to the minimal clinically important change of 0.2 mm.

RESULTS

The first measurement round revealed intra- and inter-rater ICCs of > 0.8. However, 28 sites (9 %) were unreadable, and 97 sites (32 %) revealed differences between observers of ≥ 0.5 mm. Following a consensus session and re-training, an additional 8 sites were excluded and all remaining VBL differences were ≤ 0.5 mm. Thus, the SDCs with 95 % credibility were improved from 0.73 to 0.31 mm in the intra-rater and from 1.52 to 0.34 mm in the inter-rater statistics. Given a 50 % credibility for this special setting, both the intra- and inter-rater SDCs were 0.11 mm.

CONCLUSIONS

Digital PR can be reliably utilized to determine VBLs around MIs under conditions of at least two trained observers, mutual calibration sessions, and exclusion of unquantifiable radiographs.

GERMAN CLINICAL TRIALS REGISTER ID

DRKS00007589, www.germanctr.de.

Panoramic errors in pediatric patients with special needs

This study aimed to analyze the types and frequencies of panoramic technical errors in pediatric patients with special needs, as compared to matching images of patients with normal developmental patterns. Panoramic images of 100 pediatric patients, with equal numbers of either special needs or healthy controls, referred to our Oral Maxillofacial Imaging unit, were retrospectively examined by four blinded observers for the presence of four common technical errors: palatoglossal air space, movement, positioning errors, and foreign bodies appearance. In addition, they subjectively determined the image quality on an ordinal scale. The statistical examination included inter-observer correlation and correlations between demographic factors (age, gender, developmental status) and the number and types of errors. The frequencies of demonstrated errors were, in descending order: movement, positioning, palatoglossal air space, and foreign bodies' appearance. The special needs group images showed significantly more errors and were rated as low-quality radiographs. Younger patients in both groups showed more movement and positioning errors. Technical errors in panoramic images of patients with special needs were more frequently found. Therefore, increased awareness of the staff and appropriate pre-imaging instructions to the patients, are required when imaging pediatric patients, especially those with special needs.

Apical periodontitis and autoimmune diseases-should we be screening patients prior to therapy?

DESIGN

A single-centre retrospective case-control study from 2012-2020 comparing the prevalence of apical periodontitis (AP) in patients with autoimmune disorders (AD) against a control group of those without. The different medication groups commonly used for treatment of AD were included for comparison.

CASE/CONTROL SELECTION

This study utilised patients' electronic records. These were anonymous. Patient sociodemographic variables were collected and compared. Two cases were removed from selection as they were being treated with dual biologic therapy.

DATA ANALYSIS

Both the control group and AP group contained 89 patients. Various additional variables were considered, such as DMFT and a logistical regression analysis was used to correlate between AD and AP.

RESULTS

For the autoimmune disease conditions within this study, the authors found a higher prevalence of apical periodontitis than in the control group, 89.9% versus 74.2%, respectively (p = 0.015). Furthermore, those taking conventional disease-modifying drugs such as methotrexate had a lower prevalence than those on biologics. These results were of statistical significance.

CONCLUSIONS

Individuals with autoimmune disorders may have increased prevalence of apical periodontitis irrespective of their treatment with biologics or not. A DMFT score can be used to predict the occurrence of AP.

Fusion extracted features from deep learning for identification of multiple positioning errors in dental panoramic imaging

BACKGROUND

Dental panoramic imaging plays a pivotal role in dentistry for diagnosis and treatment planning. However, correctly positioning patients can be challenging for technicians due to the complexity of the imaging equipment and variations in patient anatomy, leading to positioning errors. These errors can compromise image quality and potentially result in misdiagnoses.

OBJECTIVE

This research aims to develop and validate a deep learning model capable of accurately and efficiently identifying multiple positioning errors in dental panoramic imaging.

METHODS AND MATERIALS

This retrospective study used 552 panoramic images selected from a hospital Picture Archiving and Communication System (PACS). We defined six types of errors (E1-E6) namely, (1) slumped position, (2) chin tipped low, (3) open lip, (4) head turned to one side, (5) head tilted to one side, and (6) tongue against the palate. First, six Convolutional Neural Network (CNN) models were employed to extract image features, which were then fused using transfer learning. Next, a Support Vector Machine (SVM) was applied to create a classifier for multiple positioning errors, using the fused image features. Finally, the classifier performance was evaluated using 3 indices of precision, recall rate, and accuracy.

RESULTS

Experimental results show that the fusion of image features with six binary SVM classifiers yielded high accuracy, recall rates, and precision. Specifically, the classifier achieved an accuracy of 0.832 for identifying multiple positioning errors.

CONCLUSIONS

This study demonstrates that six SVM classifiers effectively identify multiple positioning errors in dental panoramic imaging. The fusion of extracted image features and the employment of SVM classifiers improve diagnostic precision, suggesting potential enhancements in dental imaging efficiency and diagnostic accuracy. Future research should consider larger datasets and explore real-time clinical application.

Post-Traumatic-Related Technical Errors in Orthopantomographic Imaging

Background: This study aimed at identifying errors encountered in orthopantomography (OPG) in post-traumatic patients caused by limitations in performing a correct technique. Methods: A retrospective observational study was performed. Diagnosis, exposure/processing mistakes, positioning-related errors, and bimaxillary immobilization were evaluated. Results: Thirty panoramic radiographs with mandible fractures were examined. Twelve error types were encountered: errors in exposure or processing, air radiolucency in the palatoglossal space, errors in the alignment of the Frankfort horizontal plane: head in flexion, with a joyful expression or head extended, with a somber appearance, errors towards the mid-sagittal plane (lateral head inclination, deviation, or rotation), errors caused by the non-use of the bite-block or inappropriate position on the device, errors caused by positioning outside the focal plane, artifacts/shadow images produced by post-operative metal plates, and bimaxillary immobilization errors. The number of errors per radiograph ranged from two to a maximum of five. The most dominant ones were inappropriate alignment in the focal plane and lateral rotation of the head in over 70% of cases. Lateral deviation and palatoglossal air were present in more than 50% of images. Conclusions: In trauma cases, technical difficulties in obtaining a proper OPG image are common and often insurmountable, limiting the diagnosis.

Panoramic radiography and patients with disability: a new simple breathing technique to reduce common airspace error

Patients with intellectual disabilities often fail to follow traditional tongue position instructions for panoramic radiographs resulting in missed pathology or unnecessary further radiation. This simple breathing technique is a new clinical instruction method for panoramic radiography developed to reduce the most common patient position error: patient failure to hold the tongue to the roof of the mouth. The technique is suitable for all patients including young patients and those with intellectual disabilities. The simple breathing technique uses 'tell-show-do' communication methods and does not mention the tongue but utilises the known tongue positions that occur during breathing and swallowing. This simple breathing technique instruction for panoramic radiography uses a demonstration of 'breathe-in, breathe-out, swallow, lips closed and hold still' to reduce the intensity of both the palatoglossal and pharyngeal airspaces on panoramic radiographs. This method, referred in this article as the simple breathing technique, can improve the diagnostic potential of panoramic radiographs and can be used with young children and patients with intellectual disabilities, and this slow breathing technique can help them further relax.

Tooth detection for each tooth type by application of faster R-CNNs to divided analysis areas of dental panoramic X-ray images

This study aimed to propose a computerized method for detecting the tooth region for each tooth type as the initial stage in the development of a computer-aided diagnosis (CAD) scheme for dental panoramic X-ray images. Our database consists of 160 panoramic dental X-ray images obtained from 160 adult patients. To reduce false positives (FPs), the proposed method first extracts a rectangular area including all teeth from a dental panoramic X-ray image with a faster region using a convolutional neural network (Faster R-CNN). From the rectangular area including all teeth, six divided areas are then extracted with Faster R-CNN: top left, top center, top right, bottom left, bottom center, and bottom right. Faster R-CNNs for detecting tooth regions for each tooth type were trained individually for each of the divided areas that narrowed down the target tooth types. By applying these Faster R-CNNs to each divided area, the bounding boxes of each tooth were detected and classified into 32 tooth types. A k-fold cross-validation method with k = 4 was used for training and testing the proposed method. The detection rate for each tooth, number of FPs per image, mean intersection over union for each tooth, and classification accuracy for the 32 tooth types were 98.9%, 0.415, 0.748, and 91.7%, respectively, showing an improvement compared to the application of the Faster R-CNN once to the entire image (98.0%, 1.194, 0.736, and 88.8%).

Improper patient positioning incidence for panoramic radiographic imaging of pediatric patients: Retrospective study

Background/Aim: Improper positioning of the patient reduces the diagnostic quality of panoramic radiographs. It is important to perfect the panoramic patient positioning technique to avoid unnecessary repeat exposures especially in pediatric patients. In this study, pediatric patient sample of records collected from an oral and dental health center were analyzed to determine the relative incidence of positioning errors of panoramic radiographs. Material and Methods: 3788 (1928 girls, 1860 boys) digital panoramic radiographs obtained from the stored data in the system were selected randomly. The radiographs were evaluated by two radiology specialists, by recording separately. The positioning errors of the images were categorized into ten groups: the chin tipped high, chin tipped low, a slumped position, the patient positioned forward, the patient positioned backward, failure to position the tongue against the palate, patient movement during exposure, the head tilted, and the head turned to one side. The results were statistically analyzed for positioning errors according to age and gender. Results: In 3788 radiographs, 2138 (56.4%) were error-free and 1650 (43.6%) were present with positioning errors. In the improper images, a single positional error was present in 1379 (83.6%); two positional errors were present in 248 (15%) and three or more positional errors in 23 (1.4%). The most common error observed was the tongue not being in contact with the hard palate (32.1%). On the other hand, the least common experienced error was patient movement during exposure (2.0%). Conclusions: The positioning errors of panoramic radiographs were common in the sample group of this study. Careful patient positioning can play a significant role in improving the radiographic quality and reducing the number of retakes.

Basic Knowledge and New Advances in Panoramic Radiography Imaging Techniques: A Narrative Review on What Dentists and Radiologists Should Know

Objectives: A panoramic radiograph (PAN) is the most frequently diagnostic imaging technique carried out in dentistry and oral surgery. The correct performance of image acquisition is crucial to obtain adequate image quality. The aim of the present study is to (i) review the principles of PAN image acquisition and (ii) describe positioning errors and artefacts that may affect PAN image quality. Methods: Articles regarding PAN acquisition principles, patient’s positioning errors, artefacts, and image quality were retrieved from the literature. Results: Head orientation is of the utmost importance in guaranteeing correct image acquisition. Symmetry, occlusal plane inclination, mandibular condyles localization, cervical spine position, aspect of upper teeth root apexes, exposure parameters, and metal and motion artefacts are factors that greatly affect the image quality of a successful PAN. Conclusions: Several factors are the basis for PAN performance; therefore, a systematic approach that takes into account correct patient positioning and preparation is strongly suggested to improve overall examination quality.

Does the Retromolar Area Provide Adequate Space for an Oral Endotracheal Tube Without Interfering With Intermaxillary Fixation?

PURPOSE

Traumatic maxillofacial injuries requiring intermaxillary fixation (IMF) traditionally necessitate airway management via tracheostomy or submental intubation. The aim of this study is to understand whether the retromolar space can accommodate passage of a reinforced endotracheal tube (ETT) without interfering with establishing IMF, a technique previously described as retromolar intubation.

METHODS

A retrospective cross-sectional study was created including previously treated facial trauma patients by our department as the study sample. From this group, 3D reconstructed scans were created and used to estimate that dimensions of the retromolar space. The averages of these dimensions were calculated and compared to the area occupied by different sized reinforced ETTs (6.0, 6.5, 7.0, 7.5, 8.0). A 1-sample t-test was used to compare the retromolar areas to each ETT size for all patients and by gender.

RESULTS

Forty-one patients, ages 19-69 years old, treated from July 2010 to November 2018 were included in this study. This included 24 males (21-69yo) and 17 females (19-60yo), with a total of 80 characteristics measured. The retromolar areas calculated were statistically bigger than the reinforced ETT sizes 6.0, 6.5, and 7.0 compared to the average retromolar space area, but not statistically significant for reinforced oral ETT sizes 7.5 and 8.0.

CONCLUSION

Our study results suggest the use of 6.0, 6.5 and 7.0 reinforced ETTs can be positioned in the retromolar space, allowing the surgeon to place a patient in IMF without occlusal interference. This technique could provide an alternative option to submental intubation or tracheostomy.

Evaluation of Panoramic Radiographs in Relation to the Mandibular Third Molar and to Incidental Findings in an Adult Population

OBJECTIVES

 The aim was to evaluate the characteristics of the mandibular third molars, especially in relation to the inferior alveolar nerve. Further aims were to investigate incidental findings in panoramic radiographs in an adult population, and to investigate image quality related to patient positioning.

MATERIALS AND METHODS

 From a previous study with 451 randomly selected adult participants who lived in Sweden, 442 panoramic radiographs from four dental public health clinics were used. The third molars' characteristics and relation to inferior alveolar nerve were evaluated. Incidental findings and patient positioning were recorded.

STATISTICAL ANALYSIS

 Frequency analysis was used to investigate the occurrence of all findings and their possible interconnections. Whether the patients' age or gender had an impact or not was also analyzed.

RESULTS

 The third molars were erupted in vertical position among 73% regardless of age. When retained or semi-retained, they were most commonly in mesioangular positions. The inferior alveolar nerve was located inferior to the roots in 52%, whereas an overlapped position was most common if the third molar was retained (90%), semi-retained (83%) or the age was less than 30 years (66%). Common incidental findings were apical radiolucencies, idiopathic osteosclerosis, and tooth fragments. Suboptimal patient positioning was found in one-third of the radiographs.

CONCLUSIONS

 Panoramic radiography is a useful method to evaluate third molar prior to surgical removal and may be the only image required. Most incidental findings on panoramic radiographs does not seem to require any further odontological management.

Effects of scanning parameters reduction in dental radiographs on image quality and diagnostic performance: A randomised controlled trial

OBJECTIVES

To investigate the effect of reducing scanning parameters of digital dental panoramic tomogram (DPT) and lateral cephalometric (LC) radiographs on quality and diagnostic performance of the images.

DESIGN

Single-centre prospective two-arm parallel randomised controlled trial.

SETTING

Orthodontic Clinic, Faculty of Dentistry, Universiti Teknologi MARA, Selangor, Malaysia.

PARTICIPANTS

Adult orthodontic patients aged 18-35 years, indicated for DPT and LC, who were fit and healthy with a body mass index of 18.5-25.0, not contraindicated to radiographic examination, not pregnant, and did not have a history of facial or skeletal abnormalities or bone diseases were included.

METHODS

Thirty-eight adult orthodontic patients were randomised into control and intervention groups. DPT and LC radiographs in the control group were obtained using standard scanning parameters as prescribed by the manufacturer using Orthopantomograph® OP300 by Instrumentarium. Scanning parameters in the intervention group were reduced by 60% for DPT (60 kV, 3.2 mA) and 30% for LC (85 kV, 8 mA). A five-point rating scale was used for the assessment of image quality. Images were evaluated for diagnostic performance by detection of anatomical landmarks. Mann-Whitney test was performed to compare the quality and diagnostic performance of the images and the observer agreement was assessed using the intraclass correlation coefficient (ICC).

RESULTS

For image quality, the control group produced slightly lower median scores (DPT 2.0, LC 2.0) compared to the intervention group (DPT 2.0, LC 3.0). For diagnostic performance, both groups showed similar median scores (DPT 21.0, LC 32.0). The differences between control and intervention groups for both modalities were not statistically significant. The average scores for intra-observer agreement were excellent (ICC 0.917) and inter-observer agreement was good (ICC 0.822).

CONCLUSION

Minimising radiation exposure by reducing scanning parameters on digital DPT by 60% and LC by 30% on Intsrumentarium 300 OP did not affect the quality and diagnostic performance of the images. Thus, scanning parameters on digital DPT and LC should be reduced when taking radiographs.

Custom Focal Trough in Cone-Beam Computed Tomography Reformatted Panoramic Versus Digital Panoramic for Mental Foramen Position to Aid Implant Planning

Objectives:

To compare the linear measurements from digital panoramic (DP) radiographs and cone-beam computed tomography (CBCT) volumes for the localization of the mental foramen (MF).

Material and Methods:

Thirty-one patients with panoramic and CBCT radiographs depicted on the same machine were analyzed. The vertical and horizontal positions of the MF were compared by the differences in distances measured from reference points to the boundaries (tangents) of the MF in digital panoramic (DP) and CBCT reformatted panoramic (CRP) views. The vertical position of MF was also analyzed on CBCT oblique coronal views (CORO) and compared with its corresponding distances on DP and CRP views.

Results:

Statistically significant differences (P < 0.05) were found in all compared measurements between CRP and DP views. In addition, the vertical distance (Y1) compared between DP, CRP, and CORO views also showed a statistically significant measurement discrepancy in the mean distance (P < 0.000) with the highest mean difference of 1.59 mm (P < 0.05) was attained from Y1 (DP-CORO). Inter- and intra-examiner analysis indicated a high level of agreement for all measurements.

Conclusion:

The mean values of discrepancies in measurements between DP and CRP views for horizontal and vertical linear measurements were clinically tolerable. Nevertheless, significant differences in the vertical MF position were detected between the panoramic views (DP, CRP) and the coronal views (CORO). This implies that the use of coronal view measurements during implant planning might reduce the risk of neurovascular injuries.

Prediction of maxillary canine impaction based on panoramic radiographs

OBJECTIVES

The objective of this article is to establish a large sample-based prediction model for maxillary canine impaction based on linear and angular measurements on panoramic radiographs and to validate this model.

MATERIALS AND METHODS

All patients with at least two panoramic radiographs taken between the ages of 7 and 14 years with an interval of minimum 1 year and maximum 3 years (T1 and T2) were selected from the Department of Oral Health Sciences, University Hospital Leuven database. Linear and angular measurements were performed at T1. From 2361 records, 572 patients with unilateral or bilateral canine impaction were selected at T1. Of those, 306 patients were still untreated at T2 and were used as study sample. To construct the prediction model, logistic regression analysis was used.

RESULTS

The parameters analyzed through backward selection procedure were canine to midline angle, canine to first premolar angle, canine cusp to midline distance, canine cusp to maxillary plane distance, sector, quadratic trends for continuous predictors, and all pairwise interactions. The final model was applied to calculate the likelihood of impaction and yielded an area under the curve equal to 0.783 (95% CI [0.742-0.823]). The cut-off point was fixed on 0.342 with a sensitivity of 0.800 and a specificity of 0.598. The cross-validated area under the curve was equal to 0.750 (95% CI [0.700, 0.799]).

CONCLUSION

The prediction model based on the above mentioned parameters measured on panoramic radiographs is a valuable tool to decide between early intervention and regular follow-up of impacted canines.

Dentists' use of digital radiographic techniques: Part II - extraoral radiography: a questionnaire study of Swedish dentists

OBJECTIVE

The present study aims to gain knowledge about the dentist's use and choice of digital extraoral imaging methods, panoramic radiography and cone beam computed tomography (CBCT).

MATERIALS AND METHODS

A questionnaire sent to 2481 dentists within the Swedish Dental Society contained questions about the panoramic technique and CBCT technique used, education, clinic size and type of service. The response rate was 53%.

RESULTS

The study showed that 61% of the Swedish dentists had access to panoramic techniques and that 84% used a direct digital sensor, while 6% used storage phosphor plate techniques. Around 8% of the Swedish dentists had access to CBCT. It was also observed that group practices had two times higher odds of having panoramic equipment compared with solo practices. Approximately 40% of the dentists had undergone postgraduate education in oral radiology during the last 5 years. Dental nurses and dental hygienists exposed 92% of the panoramic radiographs and 75% of the CBCTs. Thirty per cent of those clinics with access to a panoramic unit exposed >30 panoramic radiographs per month and 56% of the clinics having access to CBCT did more than 75 examinations per year.

CONCLUSIONS

Today 61% of Swedish dentists have access to panoramic radiography and 8% have access to CBCT. There is a greater likelihood of having access if the dentist works in the public dental health service or in a group practice and if the dentist has undergone any postgraduate course in oral radiology.

Dental Students' Interpretations of Digital Panoramic Radiographs on Completely Edentate Patients

The ability of dental students to interpret digital panoramic radiographs (PANs) of edentulous patients has not been documented. The aim of this retrospective study was to compare the ability of second-year (D2) dental students with that of third- and fourth-year (D3-D4) dental students to interpret and identify positional errors in digital PANs obtained from patients with complete edentulism. A total of 169 digital PANs from edentulous patients were assessed by D2 (n=84) and D3-D4 (n=85) dental students at one Canadian dental school. The correctness of the students' interpretations was determined by comparison to a gold standard established by assessments of the same PANs by two experts (a graduate student in prosthodontics and an oral and maxillofacial radiologist). Data collected were from September 1, 2006, when digital radiography was implemented at the university, to December 31, 2012. Nearly all (95%) of the PANs were acceptable diagnostically despite a high proportion (92%) of positional errors detected. A total of 301 positional errors were identified in the sample. The D2 students identified significantly more (p=0.002) positional errors than the D3-D4 students. There was no significant difference (p=0.059) in the distribution of radiographic interpretation errors between the two student groups when compared to the gold standard. Overall, the category of extragnathic findings had the highest number of false negatives (43) reported. In this study, dental students interpreted digital PANs of edentulous patients satisfactorily, but they were more adept at identifying radiographic findings compared to positional errors. Students should be reminded to examine the entire radiograph thoroughly to ensure extragnathic findings are not missed and to recognize and report patient positional errors.

Mandibular Canal Enlargement: Clinical and Radiological Characteristics

Enlargement of the mandibular canal is a rare radiological finding. Clinically, it may or may not be associated with sensory deficits. We report four cases of widening of the mandibular canal observed with various methods of imaging with different clinical characteristics. We describe this unique radiological finding and elaborate the importance of quality assessment of the imaging that is vital for accurate diagnosis and treatment planning. Clinicians should be mindful when assessing the imaging whenever the size of the mandibular canal is implicated. The case ranged from a benign tumor to malignancy, radiological errors, and artifacts. A more superior imaging or treatment modality was necessary to ascertain the diagnosis.

Panoramic radiographs made before complete removable dental prostheses fabrication: A retrospective study of clinical significance

STATEMENT OF PROBLEM

The value of digital panoramic radiographs to screen for problems before fabricating conventional complete dentures is unclear.

PURPOSE

The purpose of this retrospective study was to examine the influence of pretreatment digital panoramic radiographs on the clinical management of patients receiving complete removable dental prostheses.

MATERIAL AND METHODS

The clinical records, including panoramic radiographs, of 169 patients seeking new complete removable dental prostheses over a 6-year period were interpreted independently by both a prosthodontist and an oral and maxillofacial radiologist to identify radiographic findings that influenced clinical patient management. A 95% confidence interval and an observed proportion of agreement were used to interpret the results.

RESULTS

Sixty percent of the 169 radiographs examined had 1 or more abnormal or positive radiographic findings; however, only 6 (<4%) of 165 abnormalities detected influenced patient management, and 3 of them were identified during the clinical examination.

CONCLUSIONS

Pretreatment digital panoramic radiographs revealed very few abnormalities that influenced the treatment of patients requiring complete removable dental prostheses. Furthermore, the digital images in this study revealed positive findings at a rate similar to those found in studies assessing analog radiographs, reinforcing current guidelines that recommend against radiographic screening of patients who seek new complete removable dental prostheses.

Assessment of panoral radiograph quality in a dental treatment center

Purpose

The quality of orthopantogram (OPG) images is primarily a function of patient positioning during image capture. The purpose of the investigation was to evaluate the quality of digital panoral radiographic images obtained by using the same imaging device in a large dental treatment center on the basis of the radiography technician operator securing the image.

Materials and Methods

Three hundred OPGs radiographs taken on a Kodak 8000C Digital Panoramic and Cephalometric System device in a large dental treatment center comprised the sample. The most recent OPGs beginning at May 2010 through 2007 were selected for three radiography technicians until subgroups of 100 OPGs per technician were obtained. Each panoral was evaluated by two investigators for 21 OPG image errors.

Results

Mean panoral total score was 14.71 and mean grade was 2.41 for the entire sample indicating a “good” quality. Significant differences were found among technicians for 3 of 21 panoral fault variables. The relative contribution to inferior OPG quality was greatest for the following positioning faults in rank order: Gazebo effect (11.3%), condyles pushed out (11.0%), unclear nasal structures (10.0%), airspace over U6s (9.5%), and condyles image top (9.0%).

Conclusions

There were no significant differences among technicians for overall quality indicators (total score and grade). However, statistically significant differences among the three technicians were found for image error wide anterior teeth, Gazebo effect, and unclear nasal structures.

A new bite block for panoramic radiographs of anterior edentulous patients: A technical report

Purpose

Panoramic radiographs taken using conventional chin-support devices have often presented problems with positioning accuracy and reproducibility. The aim of this report was to propose a new bite block for panoramic radiographs of anterior edentulous patients that better addresses these two issues.

Materials and Methods

A new panoramic radiography bite block similar to the bite block for dentulous patients was developed to enable proper positioning stability for edentulous patients. The new bite block was designed and implemented in light of previous studies. The height of the new bite block was 18 mm and to compensate for the horizontal edentulous space, its horizontal width was 7 mm. The panoramic radiographs using the new bite block were compared with those using the conventional chin-support device.

Results

Panoramic radiographs taken with the new bite block showed better stability and bilateral symmetry than those taken with the conventional chin-support device. Patients also showed less movement and more stable positioning during panoramic radiography with the new bite block.

Conclusion

Conventional errors in panoramic radiographs of edentulous patients could be caused by unreliability of the chin-support device. The newly proposed bite block for panoramic radiographs of edentulous patients showed better reliability. Further study is required to evaluate the image quality and reproducibility of images with the new bite block.

Common positioning errors in panoramic radiography: A review

Professionals performing radiographic examinations are responsible for maintaining optimal image quality for accurate diagnoses. These professionals must competently execute techniques such as film manipulation and processing to minimize patient exposure to radiation. Improper performance by the professional and/or patient may result in a radiographic image of unsatisfactory quality that can also lead to a misdiagnosis and the development of an inadequate treatment plan. Currently, the most commonly performed extraoral examination is panoramic radiography. The invention of panoramic radiography has resulted in improvements in image quality with decreased exposure to radiation and at a low cost. However, this technique requires careful, accurate positioning of the patient's teeth and surrounding maxillofacial bone structure within the focal trough. Therefore, we reviewed the literature for the most common types of positioning errors in panoramic radiography to suggest the correct techniques. We would also discuss how to determine if the most common positioning errors occurred in panoramic radiography, such as in the positioning of the patient's head, tongue, chin, or body.