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Radiography wide usage in root canal treatments and developer age important role on attaining definite diagnosis, the present study examined the developer age effects on the diagnostic accuracy of endodontic file's length using D-speed, E-speed and E/F-speed films. In this diagnostic study, radiographies were processed by developer weekly up to 6 weeks. The films were viewed by 5 postgraduate Endodontics and Radiology students who assessed file tip position, using a 3-point confidence scale. The area under the curve (Az) were calculated and used as a diagnostic accuracy scale. Film types and endodontic file size effects were analyzed by one-way analysis of variance (ANOVA), Tukey post hoc and student t tests. E-speed and D-speed film diagnostic accuracy were similar being higher than E/F speed films (p<0.0001). D, E, and E/F films. Az values in fresh, 2 week and 4 week developer were 0.5882, 0.5538, 0.3578 and 0.5782, 0.5718, 0.3498 and 0.6196, 0.6724, 0.2080 respectively. Developer age did not decrease the D and E film diagnostic accuracy but reducing E/F films on 4 weeks. The 6 weeks developer caused the radiographies not to be readable. All observers showed higher diagnostic accuracy viewing endodontic file size of 15 than 10 (p<0.0001). The mean Az values in endodontic file size of 10 and 15 using fresh, 2 weeks and 4 weeks developer age were 0.3984, and 0.6016, 0.3732, and 0.6268, 0.2774 and 0.7226. The developer age up to 4 weeks did not significantly affect the diagnostic accuracy of D-speed and E-speed films. E/F films cannot be used in developer older than 2 weeks; however, its usage was associated with lower accuracies compared to E and D-speed films.

Use of panoramic radiography in some cases is easier and more cost-effective than other radiographies. However، it has some limitations as well. Considering the importance of radiography in dentistry، the present study sought to assess the consistency of selection of panoramic radiography by general dentists in Tehranwith FDA guidelines during 2010-2011.

In this descriptive cross-sectional study، 500 general dentists were selected using randomized cluster sampling and evaluated by a questionnaire. The questionnaire asked for demographic data and had 27 questions regarding the selection criteria for panoramic radiography. Dentists had the following answer choices for each criterion: “Strongly leads to prescription”، “probably leads to prescription”، “has no effect on prescription”، “probably prevents prescription” and “strongly prevents prescription”. The answers were collected and descriptively analyzed. To evaluate the effect of different factors on dentists’ answers، binary logistic regression with enter method was used.

Of the understudy dentists، 44% were females and 56% were males with a mean age of 36. 84 yrs. Based on the results of regression analysis، panoramic radiography was prescribed by dentists in case of concerns regarding the carcinogenicity of radiation، good oral hygiene and for evaluation of growth and development before the age of 6 which are not in accord with the FDA guidelines. Also، for primary assessment of periodontal status، poor oral hygiene، disseminated pain، determination of alveolar crest height in the anterior region and pregnancy، panoramic radiography was prescribed by dentists which is completely in agreement with the FDA guidelines (P<0. 05).

Easy application of panoramic radiography and its accessibility were the reasons for its prescription in 55. 5% and 47. 6% of cases، respectively. Some reasons of prescription were in accord with the FDA guidelines while some others were in contrast to them.

Panoramic radiography is the preoperative imaging technique of choice for impacted mandibular third molar surgery. However، controversy exists regarding the ability of panoramic radiography in determining the relationship of the mandibular third molar roots with the inferior alveolar canal. This study aimed to assess the ability of panoramic radiography in determining the relationship of mandibular third molar roots with the inferior alveolar nerve (IAN) canal.

This diagnostic accuracy study was conducted on 100 panoramic radiographs that were evaluated by 5 oral and maxillofacial surgery residents. They offered their expert opinion on the relationship of third molars with the IAN canal based on panoramic radiographs. These perspectives were compared with the actual post-surgical findings. Kappa and weighted Kappa reproducibility tests were used for data analysis.

Among 100 understudy cases، physical contact between the mandibular third molar roots and the canal was not observed in 88 cases intra-operatively; while this relationship existed in 12 cases. The panoramic radiography had a diagnostic sensitivity of 83. 3%، specificity of 83%، positive predictive value of 40% and negative predictive value of 97. 3%. The overall accuracy was 85%. Kappa and weighted Kappa coefficients of reproducibility were 61% and 79%، respectively.

Panoramic radiography can be confidently used as the most reliable and commonly accessible imaging technique. Considering the obtained negative predictive value، panoramic radiography is capable of revealing the involvement of third molar roots with the IAN canal with 97. 3% accuracy. Panoramic radiography had a low diagnostic value in determining the morphology of roots.

External root resorption is not detectable clinically and radiography plays a key role in its diagnosis.The present study aimed at comparing the diagnostic efficacy of conventional anddigital radiography in detection of simulated root resorption cavities (In-vitro). This experimental observational study evaluated 39 extracted teeth. All roots, except for the palatal root of upper molars,were hypotheticallydividedinto apical and coronal sections.Half these sites were considered as the control group. Buccal cavities were randomly made in the remaining sectionsusing # 1/2,2 and 4 round burrs.Each tooth was imaged using a CCD-based digital system and E-speed film. Radiographs were taken at 0 and 20˚ mesial angulation. Six image groups were interpreted by two experienced oral and maxillofacial radiologists and one endodontist.Conventional and enhanced digital radiographs were also takenat 0 and 20˚ mesial angulation. Conventional radiographs were viewedat 2X magnification by a magnifying glass. Sensitivity, specificity,false positive and false negative percentages and accuracyof each method were compared with the gold standard. The degree of agreement among these techniques was measuredbykappa coefficient. Conventional radiography at 2X magnification had the highest sensitivity and specificity. No significant difference was found in sensitivity of digital radiography and enhanced digital radiography. Enhanced digital radiography ranked second in terms of specificity. Conventional radiography at 2X magnification followed by enhanced digital radiography had the highest diagnostic accuracy. Mesial angulation of the cone increasedsensitivity and decreased specificity in all three techniques and thus, it only improved the diagnostic accuracy of digital radiography with no significant effect on the other two techniques.The degree of agreement between the two digital techniques was higher (k=0.68). Diagnostic efficacy of conventional radiography at 2X magnification is more than digital radiographs for detection of external root resorption.

Accurate and early detection of a carious lesioncan prevent its further extension. Therefore, capability to accurately diagnose carious lesions is a must-have qualification for dental graduates. The purpose of this study was to evaluate the ability of senior dental students of a dental university in detecting the presence and diagnosing the depth of proximal caries on a bitewing radiograph.

The present study was a diagnostic assessment and a total of 100 bitewing radiographs of optimal quality were randomly selected from patients’ files. Radiographs were separately observed by 30 senior dental students and 5 university professors from Shahid Beheshti School of Dentistry (in order to determine the gold standard) under similar conditions. The observers were asked to detect presence of carious lesions and diagnose its depth according to the set criteria and mark in the questionnaire. If 3 university professors unanimously agreed on presence or absence of caries, this opinion would be chosen as the gold standard of the study. In order to obtain reliability, radiographs were once again observed and evaluated one month later by the same 5 university professors and 11 students. Data were analyzed using SPSS software and Kappa values were analyzed and compared with t-test.

The mean Kappa value for 2 times observation was 0.777±0.065 among professors and 0.664±0.131 among students. According to Fleiss, this rate was excellent for 3 professors and 3 students. Diagnostic sensitivity, specificity, positive predictive value and negative predictive value of students in caries detection were 78.22%, 82.14%, 79.68% and 80.81%, respectively.

Diagnostic capability of students in differentiating carious lesions from healthy tissue was optimal and their reliability was not significantly different from the gold standard. Students were mostly able to detect the presence of carious lesions but there was an under-estimation about the depth of caries.

Radiography is considered as conventional method for caries diagnosis along with clinical examinations nowadays. Serious attempts have been made to increase diagnostic value of radiography and decrease x-ray radiation by developing different film types. The aim of present study was to assess diagnostic accuracy on detection of interproximal caries by three film types of D, E and F in in vitro conditions. In this diagnostic-invitro study, 75 human molars and premolars meeting study criteria were selected and assign in 25 blocks each having 3 teeth. The teeth were radiographed using three films of D, E and F in similar conditions using the same unit and processed similarly. Three blind and experienced radiologists assessed the radiographies and diagnosed caries. Then, the teeth were sectioned mesio-distally and examined by stereomicroscope by the magnification of ×10. The data were analyzed by diagnostic indices and analysis of variance. The sensitivity, specificity, accuracy, positive and negative predictive value of D film was 69.65%, 100%, 73.85%, 100% and 34.72% respectively. These criteria was respectively 71.30%, 94.44%, 74.43%, 98.14% and 33.94% in E film and 64.85%, 94.44%, 68.89%, 98.67% and 29.88% respectively. Analysis of variance test showed no significant differences to be found in caries depth considering film types and observers. The caries depth as determined by histopathological assessments did not show significant differences with the values determined by each observer in any film type as shown by paired t test. It seems that diagnostic criteria of three D, E and F films to be similar in the diagnosis of interproximal caries. Due to less radiation exposure, the use of F films are suggested for interproximal caries.

The aim of this research is assessment off radiation protection in Shahid Beheshti dental offices. Method & Material: This descriptive study was performed in 200 dental offices in 7 parts of Tehran under supervision of Shahid Beheshti University which were selected randomly in 2002. From these offices, 94% didn’t use Lead shielded wall, 75.5% didn’t use Lead partition, and in all of them distance between practitioner and x-ray unit was acceptable, in 1% rectangular collimator was used. The knowledge of dentists about radiation protection rules and methods were very poor and it is essential to emphasize on the radiation effects and x - ray risk and radiation protection guidelines in continuing education lectures.