Anne Møystad

Intraoral storage phosphor radiography for approximal caries detection and effect of image magnification : Comparison with conventional radiography

OBJECTIVES The aim of this study was first to test the newly developed storage phosphor (SP) system Digora for diagnostic accuracy of approximal caries detection with special emphasis on image magnification compared with conventional radiography, and second, to test whether the image surroundings could have an influence on observer performance. DESIGN SP plates and Ektaspeed films were exposed simultaneously to 50 extracted premolars/molars, and the SP image files were transported to a different platform for processing. Ten observers rated 95 approximal surfaces for caries with four imaging modalities: (1) SP images at dental film size viewed with black surroundings, (2) magnified (x4) images viewed in the same manner, (3) magnified (x4) images viewed with text and graphics framing, and (4) films viewed on a light box. The observations were validated with microscopy. Diagnostic accuracy was calculated as the area beneath the receiver operating characteristic curve (AZ). RESULTS No significant differences were found between SP images and films. Magnified SP images with text and graphics demonstrated significantly higher AZ values than nonmagnified images both for enamel and dentin, and magnified images with black surroundings demonstrated similar results for dentin. CONCLUSIONS In this in vitro material the observer performance for approximal caries detection with SP images was comparable to that with Ektaspeed films. The magnified SP images generally showed a significantly higher diagnostic accuracy than the nonmagnified SP images.

Work flow with digital intraoral radiography: A systematic review

Abstract Objective. This systematic review evaluates the six most frequently emphasized advantages of working with digital radiography: less working time, lower radiation dose to the patient, fewer retakes and errors, wider dynamic range, easier access to patient information and easier image storage and communication. Moreover, some clinical aspects and possible disadvantages of digital imaging that were not foreseen at the beginning of the digital era, such as patient discomfort, damage to the receptor, degradation of the image, cross-contamination and viewing conditions, were assessed. Material and methods. The literature search used the PubMed database with no limits and was performed during June to August 2009. Search strategies are described in the text for each of the mentioned tasks. A hand search of task-specific journals supplemented the search strategies. Results. Time seems to be saved when switching from film to digital imaging in dental practice, a dose reduction may not be obtained, retakes and errors may be increased, the dynamic range may be wider with photostimulable storage phosphor (PSP) plates but not with sensors, the effect on patient information has not been well studied and storage and communication create new challenges with regard to handling large files and image compression. In addition, patient discomfort seems to be pronounced with sensors compared with PSP plates and film, the PSP plate may be scratched in clinical use and a two-layer barrier seems to be needed to prevent contamination of the receptor. The type of monitor may not be of major concern if the image is viewed in a room with subdued light. Conclusions. Not all of the predicted advantages with digital compared to film-based radiography hold true in daily clinical work. Of particular interest is the relationship between number of images, retakes and the dose given to the patient.

Approximal Caries Depth Assessment with Storage Phosphor versus Film Radiography

Objectives: To study whether caries–specific enhancement of storage phosphor images might improve the observer performance of approximal caries depth assessments compared with film radiography. Materials and Methods: 120 exposures were made of 120 extracted human teeth. To obtain geometrically identical images, Ektaspeed Plus films and storage phosphor plates were exposed simultaneously. The imaging plates were scanned in a Digora® scanner and the files transferred to a different platform for image enhancement. Nine observers viewed films and storage phosphor images without provisions for adjustment of image intensity and contrast. For each imaging modality, 240 approximal surfaces were rated for caries on a 5–point confidence scale. Definite and probable caries lesions were also rated for lesion depth, and all ratings were compared with the histological state. Diagnostic accuracy was expressed as the area under the ROC curve (Az value). Paired t tests were used to compare the imaging modalities for diagnostic accuracy and F tests to compare observer variances. Results: Enhanced storage phosphor images demonstrated significantly higher mean Az values than film (p = 0.0066). Significantly higher mean Az values were demonstrated in the outer half of enamel (p = 0.01), but no significant differences were found between the modalities for caries lesions penetrating beyond the outer half of the enamel. The number of correctly diagnosed true–positive surfaces with caries in outer enamel was significantly higher with storage phosphor images than with film (p = 0.00014). False–positive surfaces were most frequently registered in the outer enamel with both modalities, but in this region the number of false–positive surfaces was significantly higher with storage phosphor images than with film (p = 0.0038). Pooled sensitivity and specificity values were 0.48/0.94 and 0.61/0.86 for film and storage phosphor images, respectively. The interobserver variability was significantly lower for storage phosphor images than for film. Conclusion: Enhancement of storage phosphor images with a caries–specific procedure significantly improved the accuracy of caries depth assessments in the outer half of the enamel compared with film radiography and reduced observer variability.

Injection of sodium hyaluronate compared to a corticosteroid in the treatment of patients with temporomandibular joint osteoarthritis: a CT evaluation

OBJECTIVE Osseous changes in the temporomandibular joint (TMJ) were evaluated using computed tomography (CT) examinations before and after TMJ injections of sodium hyaluronate or a corticosteroid in patients with osteoarthritis (OA). STUDY DESIGN Forty patients were randomly allocated into 2 groups for 2 intra-articular injections with either sodium hyaluronate or a corticosteroid. Bilateral TMJ examinations with high resolution CT were obtained in 36 patients before and 6 months after treatment. Treated and contralateral TMJs were evaluated for the presence of osteoarthritic osseous abnormalities by 2 reviewers independently. RESULTS Progression, regression, and no changes of osseous abnormalities were demonstrated in 13, 9, and 14 TMJs, respectively, 6 months after treatment. There was no significant difference between the groups. CONCLUSIONS Progression/regression and no changes of osteoarthritic abnormalities were observed on CT examinations in both the treated and the contralateral TMJs after treatment with intra-articular injection with sodium hyaluronate or corticosteroid.

How do dentists use CBCT in dental clinics? A Norwegian nationwide survey

Abstract Objectives. Cone beam computed tomography (CBCT) was introduced to Norwegian dental clinics in 2007. The aim of the study was to investigate how dental clinics use this imaging modality, including factors related to workflow and image quality, and to evaluate dentists’ opinions on and experiences of using it. Materials and methods. A web-based 59-item questionnaire regarding the clinical use of CBCT was sent to all 39 CBCT clinics in Norway. Results. Twenty-nine clinics (74%) responded. Most respondents (93%) were from clinics with more than one dentist and 83% had at least one specialist. All clinics had digital intraoral x-ray receptors and all but one had panoramic imaging. The most common indications for CBCT were implant treatment planning (34% of all clinics) and localization of impacted teeth (43% of specialist clinics). Seventy-two per cent of clinics reported an average of four or fewer CBCT examinations each week and 83% of respondents were subjectively satisfied with the image quality. The most commonly used enhancement functions were contrast (97%), brightness (90%) and zoom (86%). Conclusions. The Norwegian CBCT clinics surveyed were fully digitized and had multiple dentists. Periodontists and oral and maxillofacial surgeons were the most frequent specialties represented in the clinics. Clinics with only dental specialists performed more CBCT examinations/week than clinics with general practitioners or both general practitioners and specialists. The most common indications for CBCT examinations were related to treatment planning. This study found some challenges related to image quality and communication within the radiological team.

Drooling Are Botulinum Toxin Injections Into the Major Salivary Glands a Good Treatment Option

There are several treatment options available for drooling; botulinum toxin injections into the major salivary glands are one. There is no consensus as to how many and which glands should be injected. A research project on this topic was terminated because of adverse effects. Individual results and the adverse effects are described and discussed in this article. Six individuals with cerebral palsy were randomly allocated to 2 treatment groups, with five individuals receiving ultrasound-guided injections to parotid and submandibular glands and one receiving injections to the submandibular glands only. Reduction of observed drooling was registered in 3, while 4 patients reported subjective improvement (Visual Analog Scale). Two participants reported adverse effects, including dysphagia, dysarthria, and increased salivary viscosity. Injections with botulinum toxin can be a useful treatment option but there is a risk of adverse effects. Multidisciplinary evaluation and informed discussions with patients/caregivers are important factors in the decision-making process.

A phantom for simplified image quality control of dental cone beam computed tomography units

OBJECTIVE The purpose of this work was to develop an inexpensive phantom for simplified image quality assurance (IQA) together with algorithms for objective evaluation of image quality parameters and to integrate these components into an easy-to-use software package. This should help make quality control of dental cone beam computed tomography (CBCT) units accessible, easy, and affordable for any specialist or general practitioner. STUDY DESIGN Our study developed an inexpensive polymethyl methacrylate (Plexiglas) phantom containing objects and structures for objective quantification of the most important image-quality parameters in CBCT imaging. It also paired the phantom with a software package, based on open-source software, for automatic processing and analysis. RESULTS The software produces objectively measured IQA data for low- and high-contrast resolution, uniformity, noise characteristics, and geometric linearity. CONCLUSIONS The authors consider the phantom and methods presented in this article to be a step toward helping clinical dental personnel perform regular quality assurance on CBCT units.

Cephalometric analysis with digital storage phosphor images: extreme low-exposure images with and without postprocessing noise reduction.

This study evaluated extreme exposure reduction in cephalography with monitor-displayed DICOM (Digital Imaging and Communication in Medicine, Rosslyn, Va) images. The purposes were to investigate to what extent exposure can be reduced without losing diagnostic information for tracing analysis, whether postprocessing noise reduction could benefit localization of anatomic landmarks in extreme low-exposure images, and the quality of the images. Three images (optimal, extreme low exposure, and noise-reduced extreme low exposure) were obtained from 24 volunteers. Three orthodontists traced 18 landmarks and subjectively judged the quality of the images. Sixteen of the landmarks were well identified on the extreme low-exposure images when they were compared with the optimal images. Apex inferius and apex superius were not well identified. The evaluation of image quality on a visual analogue scale showed that the optimal images were given the highest scores, extreme low-exposure images with postprocessing noise reduction the second highest scores, and extreme low-exposure images the lowest scores. Monitor-based tracing analysis on storage phosphor cephalographic images with a 94% exposure reduction, compared with conventional exposure, can be performed with only 2 of 18 landmarks not well identified. The landmarks were better identified on the low-exposure images with standard postprocessing than on the images with post-processing noise reduction, although the subjective evaluation of the image quality indicated the opposite.

Comparison of the reproducibility of storage phosphor and film bitewings for assessment of alveolar bone loss

Objective. To compare bitewing storage phosphor images and a digital measuring method with bitewing films and an analog measuring method with regard to the reproducibility of measurements of alveolar bone loss. Material and methods. Nine participants randomly selected from an epidemiological study were radiographically examined using two modalities: bitewing SP images and bitewing films. A digital measuring method was used on the bitewing SP images and an analog measuring method on the bitewing films. Alveolar bone loss was measured at 12 index sites in the premolar/molar region per participant and modality. One hundred measured sites on each modality were assessed twice by three observers. Paired t-test values and intra-class correlation coefficient (ICC) were computed. Results. Comparison of the mean absolute difference of alveolar bone loss between the digital and analog measuring methods demonstrated comparable results (p=0.53). The absolute difference in millimetres between 1st and 2nd measurements was comparable for two observers and statistically different for one. Intra-observer performance between 1st and 2nd measurements was comparable for the digital (ICC=0.85) and analog (ICC=0.83) measuring methods. Inter-observer agreement for the digital measurements was higher (ICC=0.79) than for the analog measurements (ICC=0.64). Conclusions. The study demonstrates that digital and analog measuring methods are comparable with regard to absolute alveolar bone measurements and intra-observer agreement. Inter-observer comparison demonstrated significantly higher agreement for the digital measurements. Based on the overall results, the modalities with the measuring methods utilized are comparable when measuring minor alveolar bone loss.

Comparison of Swedish and Norwegian Use of Cone-Beam Computed Tomography: a Questionnaire Study.

ABSTRACT Objectives Cone-beam computed tomography in dentistry can be used in some countries by other dentists than specialists in radiology. The frequency of buying cone-beam computed tomography to examine patients is rapidly growing, thus knowledge of how to use it is very important. The aim was to compare the outcome of an investigation on the use of cone-beam computed tomography in Sweden with a previous Norwegian study, regarding specifically technical aspects. Material and Methods The questionnaire contained 45 questions, including 35 comparable questions to Norwegian clinics one year previous. Results were based on inter-comparison of the outcome from each of the two questionnaire studies. Results Responses rate was 71% in Sweden. There, most of cone-beam computed tomography (CBCT) examinations performed by dental nurses, while in Norway by specialists. More than two-thirds of the CBCT units had a scout image function, regularly used in both Sweden (79%) and Norway (75%). In Sweden 4% and in Norway 41% of the respondents did not wait for the report from the radiographic specialist before initiating treatment. Conclusions The bilateral comparison showed an overall similarity between the two countries. The survey gave explicit and important knowledge of the need for education and training of the whole team, since radiation dose to the patient could vary a lot for the same kind of radiographic examination. It is essential to establish quality assurance protocols with defined responsibilities in the team in order to maintain high diagnostic accuracy for all examinations when using cone-beam computed tomography for patient examinations.