[ comparative study of the previously graduated dentists' knowledge versus those recently graduated as to proper prescription of interaoral radiography and panoramic views]

Statement of Problems: The first step to decrease the patients' exposure to unnecessary radiography radiation is the proper prescription of radiography

Purpose: The purpose of this study was to evaluate the knowledge of general dental practitioners as to proper prescription of intraoral radiography and panoramic views

Materials and Method: In this study, a questionnaire on the dentists' knowledge about the proper prescription of dental radiography was used. A total of eighty one general dental practitioners filled in the questionnaire. Statistical analysis of the dentists' awareness and its relationship with graduate round off period was done carried out by Chisquare, Mann Whitney and Fishers exact tests using SPSS software

Results: The Knowledge of general dental practitioners as to panoramic radiography was moderate and that of those who graduated more than five years ago [Group 1] was 42.8%. The knowledge of the recently graduated general dental practitioners graduated less than 5 years ago [Group 2] was 50%. As to preference of application of panoramic radiography and intraoral periapical radiography in diagnosis of oral and dental diseases, group 1 gave 100% correct answers compared to 83.3% in group 2

Conclusion: The dentists' knowledge regarding the proper prescription of radiography did not have a significant difference. Adequate instruction for dentists in this regard seems to be necessary

[Accuracy of cone beam computed tomography, intraoral radiography and periodontal probing for periodontal bone defects measurement]

Cone beam computed tomography [CBCT] produces high-quality data about diagnosis and periodontal treatment. To date, there is not enough research regarding periodontal bone measurement using CBCT. The aim of this study was to compare the accuracy of CBCT in measuring periodontal defects to that of intraoral radiography and probing methods. Two-hundred and eighteen artificial osseous defects [buccal and lingual infrabony, interproximal, horizontal, crater, dehiscence and fenestration defects] were created on 13 mandibles of dry skulls. The mandibles were put into a plexiglass box full of water to simulate soft tissue. CBCT images, radiographic images taken with parallel technique and direct measurements using a WHO periodontal probe were recorded and compared to a standard reference [digital caliper]. Inter and intra observe consistencies were assessed using Intra class correlation coefficient and pearson correlation. Inter and intra observer consistencies were high for CBCT and probing methods [ICC-Intra class correlation coefficient>88%], but moderate for intraoral radiography [ICC-Intra class correlation coefficient>54%]. There were not any significant differences between observers for all techniques [P>0/05]. According to paired T-test analysis, mean difference for CBCT technique [0.01 mm] was lower than that for probing [0.04 mm] and radiography [0.62 mm]. CBCT was able to measure all kinds of lesions, but radiography could not measure defects in the buccal and lingual sites. All three modalities are useful for identifying periodontal defects. Compared to probing and radiography, the CBCT technique has the most accuracy in measuring periodontal defects

[ comparison of tomography's accuracy between spiral cranex tome and linear promax for evaluating the quantity of bone in posterior of maxilla]

An accurate imaging technique has an important role in implantology. Presence of sinus in the posterior maxilla is a limiting factor for implant insertion in this area. Therefore it is necessary to evaluate the relationship between alveolar ridge and sinus. The aim of the present in vitro study was to compare the accuracy of Cranex Tome Spiral and ProMax linear tomography to assess bone quality for the preoperative planning of implants in the posterior maxilla. Tomographs were taken from 3 dry human skulls using both units. Three sites were selected in each side of posterior maxilla and marked with orthodontic wires meaning a total of 24 sites [12 sites for each unit]. Bone height and width were measured first on the tomography and then on the skulls after sectioning. In order to compare the measurement values between both units and to compare them with the values obtained from gold the Intraclass Correlation of reliability [ICC] was used. The minimum Intraclass correlation coefficient of reliability was 0.569 in two times measurements of width for ProMax, and the maximum of this coefficient was 0.950 in two times measurements of height for Spiral. The mean difference between the real measurements and the height measurements of both units were less than 0.3 mm and for the width measurements were less than 0.5 mm of the real measurements. This study showed in both units, the height measurements were more accurate than the width measurements and all the measurements by Spiral were more valid then those of ProMax. Generally quantitative accuracy of Spiral unit was found to be higher than ProMax unit. Both units proved to be sufficient for quantity measurements. Adjustment an individual imaging plane for each site of tomography increases the accuracy. The most distal sites of Spiral unit may need separate adjustment other than manufacturer demands

template based on concepts of natural head position for Tabriz's adults

Template analysis is a method which consists of mean graphic face profile so that shows the discrepancies sites only by direct observation of superimposed template on the patient's cephalogram tracing. The aim of this study was to prepare a template based on concepts of natural head position for Tabriz's adults. Sixty - two lateral cephalograms based on natural head position which were obtained from students of Tabriz dentistry faculty with normal occlusion and proportional facial profile were studied. Assuming the N point as a coordinate origin and true horizontal and vertical lines as bases of coordinate axials, length and width of 32 landmarks on hard and soft tissues were determined. Mean and SD of all landmarks were determined using SPSS analysis method. A new template was designed by tracing average profile image for males and females separately in five different sizes. The template analysis based on NHP could have both advantages of using extracranial references and utilizing a quick analyzing method. The natural head position concept and the special design for orthognathic surgery, are two particular features of this template compared with the other templates described before