Bitewing Images Research Articles

Evaluation of the interpretation of bitewing radiographs in treating interproximal caries

Abstract Objective: Misinterpretation of bitewing radiographs may lead to the selection of surgical approach rather than medical approach in treating proximal caries lesions. We aimed to determine the sensitivity, specificity, and diagnostic accuracy of bitewing radiography interpretation by various groups of dentists for the detection of proximal caries and subsequent treatment decision-making. Materials and Methods: This in vitro study was performed using 60 extracted molar and premolar teeth. The target proximal carious surfaces were categorized and coded according to the International Caries Detection and Assessment System (ICDAS) as category 1: ICDAS = 0, category 2: ICDAS = 1 or 2, and category 3: ICDAS = 3, 4, or 5. All the teeth were randomly divided and mounted onto 15 quadrants made of two premolars and two molars, and a digital bitewing image was taken from each quadrant. A checklist was given to four groups of participants (dentistry students, dentists with a DDS degree, restorative dentistry specialists, and oral radiology specialists) to indicate for which lesion depth they would intervene restoratively. The data acquired through the checklists were compared with direct visual examination of target surfaces before mounting. Results: Sensitivity and accuracy of bitewing radiography showed no significant difference among the groups. However, specificity was significantly higher in Group D. Conclusions: According to our results, interpretation of bitewing radiographs was different among the groups. Although not significant, the radiologists had the highest diagnostic accuracy than the other groups of participants, and the students showed the weakest performance in the diagnosis of restorative treatment needed. Furthermore, the highest percentage of decision error occurred when lesions had ICDAS 1 or 2, followed by ICDAS 3, 4, or 5, and finally 0 in all the four groups.

QUANTIFYING PHOTOSTIMULABLE PHOSPHOR (PSP) PLATE ARTIFACTS TO STANDARDIZE RADIOLOGIC QUALITY ASSURANCE

Background With every use, photostimulable phosphor (PSP) plates accumulate physical artifacts (i.e., scratches, dents) that negatively affect image quality. Dental clinicians are responsible for monitoring these artifacts and discard plates they have deemed undiagnostic. Currently, at our institution, this is accomplished by direct visual inspection of plates for signs of wear. This arbitrary process has no objective validation leading to variability in radiologic image quality and may impair diagnostic value. Objective This study aimed to develop a metric to objectively quantify the severity of physical artifacts on PSP plates. This metric will be compared against the current standard of direct visual inspection to determine the validity of this approach for PSP quality assurance. Materials and Methods Sixty random PSP plates (CS 7600; Carestream Dental, Rochester, NY) were chosen for analysis: 36 were determined to be undiagnostic by using the current quality control standard, 20 were in active circulation, and 4 brand-new plates were used as controls. The selected plates were exposed to obtain the equivalent of a posterior bitewing image (Belmont PHOT-X II s Model 505 at 70 kV, 6 mA, 0.22 seconds), scanned, and raw DICOM images exported. A custom computer algorithm (MATLAB; Mathworks, Natick, MA) was developed to measure the inhomogeneity of the image to calculate the artifact metric. By using these, the selected plates were sorted and compared against the current quality assurance standard. Preliminary Results Preliminary results showed poor correlation between plates that were selected to be discarded by direct visual inspection and artifact metrics. Many plates that were chosen to be discarded with the current standard had a lower artifact metric compared with plates that were still in circulation. Future Directions Future studies aim to validate this metric by comparing the artifact score with qualitative grading of PSP plate artifacts and to determine a threshold for when radiologic diagnosis is impeded. With every use, photostimulable phosphor (PSP) plates accumulate physical artifacts (i.e., scratches, dents) that negatively affect image quality. Dental clinicians are responsible for monitoring these artifacts and discard plates they have deemed undiagnostic. Currently, at our institution, this is accomplished by direct visual inspection of plates for signs of wear. This arbitrary process has no objective validation leading to variability in radiologic image quality and may impair diagnostic value. This study aimed to develop a metric to objectively quantify the severity of physical artifacts on PSP plates. This metric will be compared against the current standard of direct visual inspection to determine the validity of this approach for PSP quality assurance. Sixty random PSP plates (CS 7600; Carestream Dental, Rochester, NY) were chosen for analysis: 36 were determined to be undiagnostic by using the current quality control standard, 20 were in active circulation, and 4 brand-new plates were used as controls. The selected plates were exposed to obtain the equivalent of a posterior bitewing image (Belmont PHOT-X II s Model 505 at 70 kV, 6 mA, 0.22 seconds), scanned, and raw DICOM images exported. A custom computer algorithm (MATLAB; Mathworks, Natick, MA) was developed to measure the inhomogeneity of the image to calculate the artifact metric. By using these, the selected plates were sorted and compared against the current quality assurance standard. Preliminary results showed poor correlation between plates that were selected to be discarded by direct visual inspection and artifact metrics. Many plates that were chosen to be discarded with the current standard had a lower artifact metric compared with plates that were still in circulation. Future studies aim to validate this metric by comparing the artifact score with qualitative grading of PSP plate artifacts and to determine a threshold for when radiologic diagnosis is impeded.

DENTAL RADIOGRAPHIC PRESCRIBING PRACTICES: SURVEY OF DENTAL HYGIENISTS IN THE U.S.

Background Potential harm from ionizing radiation has led to the development of guidelines to protect patients and practitioners from unnecessary radiation exposure; however, these guidelines may or may not be followed in practice. Objective This study surveyed U.S. dental hygienists with regard to radiology policies in the workplace. Methods The survey, consisting of 62 knowledge and practice items regarding use of dental radiography, was based on the 2012 publication by the American Dental Association (ADA) and the U.S. Food and Drug Administration (FDA): “Dental Radiographic Examinations: Recommendations for Patient Selection & Limiting Radiation Exposure.” The study was granted exempt status by the Texas AM for adolescent patients, corporate and general dental practices preferred to make bitewing images every 12 months, whereas educational institutions preferred to make bitewing images every 18 months (P Conclusions The findings of this study suggest that some dental practices are not strictly following the ADA/FDA guidelines with regard to frequency of radiographic exposures.

Accuracy of various imaging methods for detecting misfit at the tooth-restoration interface in posterior teeth.

PurposeThe present study aimed to evaluate which of the following imaging methods best assessed misfit at the tooth-restoration interface: (1) bitewing radiographs, both conventional and digital, performed using a photostimulable phosphor plate (PSP) and a charge-coupled device (CCD) system; (2) panoramic radiographs, both conventional and digital; and (3) cone-beam computed tomography (CBCT).Materials and MethodsForty healthy human molars with class I cavities were selected and divided into 4 groups according to the restoration that was applied: composite resin, composite resin with liner material to simulate misfit, dental amalgam, and dental amalgam with liner material to simulate misfit. Radiography and tomography were performed using the various imaging methods, and the resulting images were analyzed by 2 calibrated radiologists. The true presence or absence of misfit corresponding to an area of radiolucency in regions subjacent to the esthetic and metal restorations was validated with microscopy. The data were analyzed using a receiver operating characteristic (ROC) curve, and the scores were compared using the Cohen kappa coefficient.ResultsFor bitewing images, the digital systems (CCD and PSP) showed a higher area under the ROC curve (AUROC) for the evaluation of resin restorations, while the conventional images exhibited a larger AUROC for the evaluation of amalgam restorations. Conventional and digital panoramic radiographs did not yield good results for the evaluation of resin and amalgam restorations (P<.05). CBCT images exhibited good results for resin restorations (P>.05), but showed no discriminatory ability for amalgam restorations (P<.05).ConclusionBitewing radiographs (conventional or digital) should be the method of choice when assessing dental restoration misfit.

Repeat analysis of intraoral digital imaging performed by undergraduate students using a complementary metal oxide semiconductor sensor: An institutional case study.

PurposeThis study was performed to quantify the repeat rate of imaging acquisitions based on different clinical examinations, and to assess the prevalence of error types in intraoral bitewing and periapical imaging using a digital complementary metal-oxide-semiconductor (CMOS) intraoral sensor.Materials and MethodsA total of 8,030 intraoral images were retrospectively collected from 3 groups of undergraduate clinical dental students. The type of examination, stage of the procedure, and reasons for repetition were analysed and recorded. The repeat rate was calculated as the total number of repeated images divided by the total number of examinations. The weighted Cohen's kappa for inter- and intra-observer agreement was used after calibration and prior to image analysis.ResultsThe overall repeat rate on intraoral periapical images was 34.4%. A total of 1,978 repeated periapical images were from endodontic assessment, which included working length estimation (WLE), trial gutta-percha (tGP), obturation, and removal of gutta-percha (rGP). In the endodontic imaging, the highest repeat rate was from WLE (51.9%) followed by tGP (48.5%), obturation (42.2%), and rGP (35.6%). In bitewing images, the repeat rate was 15.1% and poor angulation was identified as the most common cause of error. A substantial level of intra- and interobserver agreement was achieved.ConclusionThe repeat rates in this study were relatively high, especially for certain clinical procedures, warranting training in optimization techniques and radiation protection. Repeat analysis should be performed from time to time to enhance quality assurance and hence deliver high-quality health services to patients.

Edge Detection and Features Extraction for Dental X-Ray

Recently, the dental X-Ray images have been used in different applications, particularly in the forensic field. The researchers focuses on the separation of the underlying teeth individually to obtain their features. These features can be utilized as a key solution for the identifications. In this paper, an edge detection of the involved teeth is proposed using a three stages MATLAB algorithm based on different methods such as, CLAHE, Canny, Otsu's, and 8-Connectivity. In addition, the proposed algorithm extracts the features of the investigated teeth as an exported file. These features are Standard Deviation (STD), Euler number and Area which are extracted from the bite-wing images. The stages of the proposed algorithm are image segmentation, classification and features extraction. It is important to note that the missing teeth has been considered in case of appearance. The missing teeth are assumed to be a separated objects. This is to overtake the problem of missing teeth after registering the original ones in the stored database used for identifications. The obtained results show the clear outperformance of the proposed algorithm in terms of edge detection and features’ extraction. The missing teeth in an image are tested and the achieved results presents the detection and features of such teeth dramatically. The proposed system is implemented and tested in the MATLAB software environment using a personal computer of a Core(TM) i7 processor and 6 GB RAM over a 64-Windows 10 operating system.

Ex vivo evaluation of new 2D and 3D dental radiographic technology for detecting caries.

Proximal dental caries remains a prevalent disease with only modest detection rates by current diagnostic systems. Many new systems are available without controlled validation of diagnostic efficacy. The objective of this study was to evaluate the diagnostic efficacy of three potentially promising new imaging systems. This study evaluated the caries detection efficacy of Schick 33 (Sirona Dental, Salzburg, Austria) intraoral digital detector images employing an advanced sharpening filter, Planmeca ProMax(®) (Planmeca Inc., Helsinki, Finland) extraoral "panoramic bitewing" images and Sirona Orthophos XG3D (Sirona Dental) CBCT images with advanced artefact reduction. Conventional photostimulable phosphor images served as the control modality. An ex vivo study design using extracted human teeth, ten expert observers and micro-CT ground truth was employed. Receiver operating characteristic analysis indicated similar diagnostic efficacy of all systems (ANOVA p > 0.05). The sensitivity of the Schick 33 images (0.48) was significantly lower than the other modalities (0.53-0.62). The specificity of the Planmeca images (0.86) was significantly lower than Schick 33 (0.96) and XG3D (0.97). The XG3D showed significantly better cavitation detection sensitivity (0.62) than the other modalities (0.48-0.57). The Schick 33 images demonstrated reduced caries sensitivity, whereas the Planmeca panoramic bitewing images demonstrated reduced specificity. XG3D with artefact reduction demonstrated elevated sensitivity and specificity for caries detection, improved depth accuracy and substantially improved cavitation detection. Care must be taken to recognize potential false-positive caries lesions with Planmeca panoramic bitewing images. Use of CBCT for caries detection must be carefully balanced with the presence of metal artefacts, time commitment, financial cost and radiation dose.

Identification of Hard and Soft Tissue Anatomical Landmarks on Dental Intraoral Periapical Radiographic Images

OPEN ACCESSAugust 31, 2015Identification of Hard and Soft Tissue Anatomical Landmarks on Dental Intraoral Periapical Radiographic Images Denise Mills, RDH, DDS, Vijay Parashar, MDS, BDS Denise Mills, RDH, DDS Midwestern University College of Dental Medicine Google Scholar More articles by this author , Vijay Parashar, MDS, BDS Midwestern University College of Dental Medicine Google Scholar More articles by this author https://doi.org/10.15766/mep_2374-8265.10185 SectionsAbout ToolsDownload Citations ShareFacebookTwitterEmail Abstract Introduction: Dental and dental hygiene students are faced with the challenge of identifying anatomical structures on two-dimensional radiographic images. To better prepare novice learners for this difficult task, this module was created as an overview of normal anatomic structures of the maxillofacial region that are frequently imaged on periapical and bitewing images. Prerequisites for participation in the presentation include competency in head and neck anatomy as well as proficiency in radiographic techniques necessary to create periapical and bitewing images. Methods: This module includes a PowerPoint presentation containing a series of radiographic images and corresponding overlaid photographic images providing an effective means for learning radiographic anatomy. Multiple-choice questions (answer key included for second portion of the presentation) in the presentation with identified responses make it a tool that is useful for lectures, small-group presentations, flipped-classroom activities, and student assessment utilizing audience response devices, written responses, or oral review. The session may be administered to small groups of approximately 12 students. Results: This presentation has been presented to over 500 dental and dental hygiene students. Prior to the addition of overlaid photographic images to the presentation, the average score was 80%. Following the addition of overlaid photographs to the presentation, the average score exceeded 90%. Student surveys had many positive responses and they found the presentation to be extremely helpful with identifying landmarks. One student responded that the mini-session was most beneficial for teaching and learning. Another commented that the presentation clearly taught the concepts and ideas. The most insightful student response commented that the presentation helped explain the concepts well and got the students to interact with, and critically think about, the material. Discussion: This presentation will help the learner connect prior knowledge of head and neck anatomy to structures observed in radiographic images. Concepts of radiolucency and radiopacity may be presented prior to the resource being used or in conjunction with the presentation. Ideas for future expansion of the presentation include adding panoramic images with superimposed photographs. Educational Objectives By the end of this presentation, students will be able to: Identify and name radiopaque and radiolucent anatomical landmarks representing normal anatomy.Identify the anatomic landmarks of the maxilla on intraoral periapical images.Identify the anatomic landmarks of the mandible on intraoral periapical images. ReferencesNabil I, Mayer RE, Schuller MJ, Wang E, Shapiro MB, DaRosa DA. Teaching for understanding in medical classrooms using multimedia design principles, Med Education.2013;47(4):388–396. http://dx.doi.org/10.1111/medu.12127Medline, Google ScholarRussell SS. An overview of adult-learning processes, Urologic Nurs.2006;26(5), 349–352.Medline, Google ScholarWhite SC, Pharoah MJ. Oral Radiology: Principles and Interpretation. 7th ed.St. Louis, MO: Elsevier; 2014.Google Scholar Sign up for the latest publications from MedEdPORTAL Add your email below FILES INCLUDEDReferencesRelatedDetails FILES INCLUDED Included in this publication: Identification of Hard and Soft Tissue Instructor's Guide.docx Identification of Hard and Soft Tissue Anatomical Landmarks on Intraoral Periapical Radiographic Images.pptx Answer Key Intraoral Radiographic Anatomy Presentation.doc To view all publication components, extract (i.e., unzip) them from the downloaded .zip file. Download editor’s noteThis publication may contain technology or a display format that is no longer in use. CitationMills D, Parashar V. Identification of Hard and Soft Tissue Anatomical Landmarks on Dental Intraoral Periapical Radiographic Images. MedEdPORTAL. 2015;11:10185. https://doi.org/10.15766/mep_2374-8265.10185 Copyright & Permissions© 2015 Mills and Parashar. This is an open-access publication distributed under the terms of the Creative Commons Attribution-NonCommercial-Share Alike license.KeywordsDental Hygiene StudentsDental StudentsPeriapical Radiographic ImagesOral HygieneReview of Radiographic LandmarksMaxillofacial Radiographic Anatomy Disclosures None to report. Funding/Support None to report. tabs.loading

A Proposed Feature Extraction Technique of Dental X-ray Bitewing Image for Human Identification

A Proposed Feature Extraction Technique of Dental X-ray Bitewing Image for Human Identification

The Comparison between Two Different Digital Panoramic Radiography Techniques in the Detection of Proximal Caries

Introduction: Although proximal dental caries are very common, clinical examinations cannot detect them all. Panoramic radiography has been widely used in dentistry for both diagnosis and screening. This study aimed to investigate and compare the efficacy of two digital panoramic radiography techniques in the diagnosis of proximal caries. Methods: A total number of 60 patients referred to a dental radiology center, all had complete dental system and bitewing radiographies, were included. The patients were randomly divided into two groups of 30 patients. For the first and second groups, CR and DR images were obtained respectively. Images were obtained from the distal of the third tooth to the distal of the eighth. Bitewing images were compared with CR and DR images regarding the detection of caries. Kappa index and chi-squared statistics were employed to analyze the results. Results: There was a high agreement rate between bitewing images and CR (Kappa=0.775) and DR (Kappa=o.762) images in detecting caries. Also no significant difference was shown between CR and DR techniques in the detection of caries (0.543). However, DR and CR images are not efficient enough to be prescribed as the sole imaging technique to detect proximal caries. Conclusion: DR and CR techniques could be good imaging techniques for the detection of dental caries as a companion to clinical examinations

Proximal caries detection accuracy using intraoral bitewing radiography, extraoral bitewing radiography and panoramic radiography

To compare proximal caries detection using intraoral bitewing, extraoral bitewing and panoramic radiography. 80 extracted human premolar and molar teeth with and without proximal caries were used. Intraoral radiographs were taken with Kodak Insight film (Eastman Kodak Co., Rochester, NY) using the bitewing technique. Extraoral bitewing and panoramic images were obtained using a Planmeca Promax Digital Panoramic X-ray unit (Planmeca Inc., Helsinki, Finland). Images were evaluated by three observers twice. In total, 160 proximal surfaces were assessed. Intra- and interobserver kappa coefficients were calculated. Scores obtained from the three techniques were compared with the histological gold standard using receiver operating characteristic analysis. Az values for each image type, observer and reading were compared using z-tests, with a significance level of α = 0.05. Kappa coefficients ranged from 0.883 to 0.963 for the intraoral bitewing, from 0.715 to 0.893 for the extraoral bitewing, and from 0.659 to 0.884 for the panoramic radiography. Interobserver agreements for the first and second readings for the intraoral bitewing images were between 0.717 and 0.780, the extraoral bitewing readings were between 0.569 and 0.707, and the panoramic images were between 0.477 and 0.740. The Az values for both readings of all three observers were highest for the intraoral bitewing. Az values for the extraoral bitewing images were higher than those of the panoramic images without statistical significance (p > 0.05). Intraoral bitewing radiography was superior to extraoral bitewing and panoramic radiography in diagnosing proximal caries of premolar and molar teeth ex vivo. Similar intra- and interobserver coefficients were calculated for extraoral bitewing and panoramic radiography.

Synthesizing Dental Radiographs for Human Identification

The task of identifying human remains based on dental comparisons of post mortem (PM) and ante mortem (AM) radiographs is labor-intensive, subjective, and has several drawbacks, including: inherently poor image quality, difficulty matching the viewing angles in PM radiographs to those taken AM, and the fact that the state of the dental remains may entirely preclude the possibility of obtaining certain types of radiographs PM. The aim of the present study was to investigate the feasibility of using radiograph-like images reconstructed from PM x-ray computed tomography (CT) data to overcome the shortcomings of conventional radiographic comparison. Algorithms for computer synthesis of panoramic, periapical, and bitewing images are presented. The algorithms were evaluated with data from clinical examinations of two persons. The results demonstrate the efficacy of the CT-based approach and that, in comparison with conventional radiographs, the synthesized images exhibit minimal geometric distortion, reduced blurring, and reduced superimposition of oral structures.

A content-based system for human identification based on bitewing dental X-ray images

This paper presents a system for assisting in human identification using dental radiographs. The goal of the system is to archive antemortem (AM) dental images and enable content-based retrieval of AM images that have similar teeth shapes to a given postmortem (PM) dental image. During archiving, the system classifies the dental images to bitewing, periapical, and panoramic views. It then segments the teeth and the bones in the bitewing images, separates each tooth into the crown and the root, and stores the contours of the teeth in the database. During retrieval, the proposed system retrieves from the AM database the images with the most similar teeth to the PM image based on Hausdorff distance measure between the teeth contours. Experiments on a small database show that our method is effective for dental image classification and teeth segmentation, provides good results for separating each tooth into crown and root, and provides a good tool for human identification.

Comparison of conventional and novel interproximal receptor positioning devices

Dental caries and marginal periodontitis cause the destruction of tooth and supporting socket bone structure, which left untreated may have serious systemic consequences and deteriorate quality of life. These common infections are detected early through use of periodic interproximal dental x-rays. While x-ray diagnosis has greatly benefited many people, it carries with it increased risk of oral carcinogenesis. Dental interproximal bitewing images are the most commonly exposed dental radiographs.

Classification and numbering of teeth in dental bitewing images

We present an algorithm to classify and assign numbers to teeth in bitewing dental images. The goal is to use the result of this algorithm in an automated dental identification system. We use Bayesian classification to classify the teeth in a bitewing image into molars and premolars and assign an absolute number to each tooth based on the common numbering system used in dentistry. Fourier descriptors of the teeth contours are used as features in the Bayesian classification. After the Bayesian classification, the spatial relation between the two types of teeth is considered to number each tooth and correct the misclassification of some teeth in order to obtain high precision results. Comparison between the two kinds of FDs was done to select the best method for teeth classification. Experiments with 50 bitewing images containing more than 400 teeth show that our method is capable of classifying and assigning absolute index number to the teeth with high accuracy.

Tuned Aperture Computed Tomography and Detection of Recurrent Caries

This study compared the diagnostic efficacy of four imaging modalities for the detection of artificially induced recurrent caries: intraoral film, direct digital bitewing images, tuned apertuce computed tomography (TACT^TM) slices and iteratively restored TACT^TM images using an in vitro model. Twenty-four posterior teeth were prepared for MOD inlay restorations. These were then restored with different restorative materials (amalgam, Herculite and Durafill). Lesions were simulated in half the number of surfaces studied. These lesions were created either at the intersection of the facial or lingual walls and the gingival floor or on the gingival floor midway between the facial and lingual walls in the proximal boxes of the MOD restorations. Analysis of observations from 8 observers using ROC curve reveal the superior diagnostic efficacy with TACT^TM iteratively restored images (A_z for TACT^TM iteratively restored images = 0.9171, TACT^TM slices = 0.7052, Film = 0.6608, direct digital images = 0.5979). ANOVA revealed significance with respect to the imaging modality used (p < 0.0001). The results suggest that TACT^TM images hold promise as a more effective imaging modality than film or direct digital systems for detection of recurrent caries.

Effects of focal spot size on caries diagnosis with D and E speed images

Annual measurement of the x-ray unit focal spot size has been recommended by the American Academy of Oral and Maxillofacial radiology as part of the dental radiographic quality control program. This study compares the effects of focal spot size on caries diagnosis. Three x-ray units with small, medium, and large focal spot sizes were used to produce bite-wing images on extracted teeth mounted in acrylic bases. Randomized films were scored for lesion presence and depth by two general dentists. Weighted kappa statistics were used to evaluate the agreement of reviewer caries diagnosis by film speed and focal spot size. Comparisons of caries cells with small versus medium and small versus large focal spot size produced weighted kappa statistics = 0.72 and 0.70, respectively. Differences in caries calls were greater because of film speed rather than focal spot size. The results of this study suggest that the clinical significance of varied focal spot size is negligible. The value of annual measurement of focal spot size is questionable, and its recommendation should be revisited.

Approximal cavitation related to bite-wing image and caries activity in adolescents.

Cavitation of enamel lesions probably represents a significant step regarding further progression of the caries process. The primary objective of this study was to examine in adolescents the macroscopical appearance of approximal surfaces with radiographic lesions and relate this to the caries activity of the individual. A second objective was to establish the clinical feasibility of a modified technique for inspection of approximal contact surfaces. The material consisted of 46 enamel lesions selected on the basis of routine bite-wing radiographs of 140 patients aged 17-18 years, available from the Public Dental Service of Lillehammer, a non-fluoridated town. Lesions close to or approaching the AD junction were classified as D2 lesions, whereas those demonstrating a shadow not more than 1 mm into the dentine were designated D3 lesions. Based on recorded treatment during the last 3 years, patients were dichotomised as caries-active (CA) if they had more than 6 new lesions involving the dentine. The remainder with little or no activity were designated modestly active (MA). A small orthodontic rubber ring was placed around the contact point of the approximal surface of interest 1 day before an impression was taken. A separation of 0.5 mm facilitated cleansing and injection of low viscosity impression material (Xantopren(R) L, Blue, Bayer Dental). Discontinuity in the approximal enamel surface, determined by visual inspection of stone dyes, prepared from the impressions, was classified as cavitation. The results demonstrated that in MA patients D2 lesions seldom had cavities while in CA patients cavitation was usually found both in D2 and D3 lesions. The feasibility of the impression/inspection method seems established. It is easily performed and should be considered as a diagnostic tool in borderline cases.

A computer-assisted method for making linear radiographic measurements using stored regions of interest.

Accurate detection of changes in alveolar bone height requires radiographic measuring methods with a reliability of standard deviation (SD) of 0.15 mm or better. No periodontal digital imaging system has reached this reliability, although 3 analogue methods have achieved this goal. However, existing linear methods are time-consuming, difficult to use, unsuitable for measuring all possible (unsharp) anatomical sites and do not provide a confidence estimate for sites of change observed in serial standardized films. A rapid computer-assisted method using stored image regions of interest (ROI) has been developed which allows retest measurements for all possible sites and automatically calculates a 90%, 95%, 98%, or 99% confidence threshold value, derived from duplicate measurement variation, for sites of apparent crest height change. 28 examiners, with minimal training in operating the system, measured 14 different cement-enamel junction to crest height distances from a standard bitewing image, with and without the ROI method. The measurements were repeated 4 weeks later. 13/14 sites achieved an intra-examiner SD threshold of less than or equal to 0.15 mm with the ROI method but 0/14 without. A higher inter-examiner SD threshold of less than or equal to 0.22 mm was achieved for 13/14 sites using ROI and 0/14 without (p less than 0.001). The measurement of crest height changes in a region of previous severe vertical bone loss is demonstrated using serial films. The potential for using trabecular bone patterns as reference sites in regions where traditional measurement points are absent is demonstrated.(ABSTRACT TRUNCATED AT 250 WORDS)

Spatial resolution requirements for digitizing dental radiographs

A study was performed to determine the appropriate spatial resolution for digitizing and transmitting dental radiographs with the KODAK EKTASCAN, a computer-based digital enhancement and transmission system Periapical, bitewing, and panoramic radiographs were digitized in three formats representing varying spatial resolution parameters. Eight viewers used a 5-point rating scale to evaluate the detectability of periapical pathosis on the periapical images, of proximal surface caries on the bitewing images, and of various bony abnormalities on the panoramic images. Receiver operating characteristic curves were generated, and the results of the periapical, bitewing and panoramic experiments were presented as trapezoidal and maximum likelihood receiver operating characteristic curve areas. The results of this study indicate that digital images of dental radiographs provide adequate diagnostic accuracy for evaluating the presence of periapical pathosis, proximal surface caries, and specified bony abnormalities. The digitization parameters established for the KODAK EKTASCAN provide a guide for digitizing dental radiographs on other commercially available digital image-processing system.