سیده طاهره محتوی پور

Estimating the canal length is essential for reaching to a proper endodontic treatment. Any error and miscalculation in estimation of the working length, especially in curved canals, can result in complication during and after root canal therapy. The introduction of digital radiography has enabled us to measure curved canal length. The purpose of this study was to evaluate the calibration tool of Complementary Metal Oxide Semiconductor (CMOS) digital system in estimation of working length.
In this in-vitro study, 80 extracted molar teeth were selected and randomly divided into three groups based on angle and radius of canal curvature. A 5 mm orthodontic wire was placed on the lateral surface of the root. Conventional radiographs were taken after insertion of endodontic file in the apical third of root canals. Radiographic images were scanned and imported to the software of CMOS digital system. Two observers estimated the file lengths with and without using calibration tool of digital measurement software. The correlation between observers was evaluated and then data were analyzed using Paired T-test with 95% confidence.
Overall agreement between observers was good. There was no significant difference between the mean values of calibrated measurement and true file length in the basis of canal curves (P>0.001). However, there was significant difference between the mean values of uncalibrated measurement and true file length in the basis of canal curvature (P The calibrated measurement of file length was more accurate than that of the uncalibrated file length measurement.

Radiographs are essential tools for detection of caries. Panoramic, periapical and bite-wing radiographs are used alone or in various combinations to detect caries. With the introduction of digital radiography, it has been used extensively in panoramic radiography. The aim of this study was to evaluate the accuracy of digital panoramic and bite-wing radiography in the detection of proximal caries.
In this analytical study, panoramic and bite-wing radiographs of 50 patients were evaluated. The radiographs were evaluated for proximal enamel and outer third dentinal caries in molar areas by two observers. Intra- and inter-observer agreement was analyzed with Cronbach's Alpha and diagnostic accuracy was evaluated using receiver operating characteristic analysis (ROC) at a significance level of α = 0.05.
Intra- and inter-observer agreement levels were high. The mean values of area under curve (AUC) were 0.978 and 0.952 for panoramic and bite-wing radiography, respectively. There were no significant differences between AUCs of these two imaging modalities (p value = 0.001).
The accuracy of panoramic radiography in evaluation of proximal caries in molar areas was comparable to that of bite-wing radiography.

Elongation of styloid process may result in development of Eagle syndrome with associated symptoms. This study aimed to assess the frequency of elongated styloid process (ESP) and to evaluate its prevalence according to sex and age.
This study was conducted on digital panoramic radiographs of patients refered to the Oral Radiology Department of dental school, Guilan University of Medical Sciences. Styloid process length was measured and classified as elongated, pseudoarticulated, or segmented. Calcification patterns were determined as A, B, C, and D. ESP was defined as length > 30 mm. Data were analyzed by SPSS using T-test, Chi square, Pearson, and Spearman (P A total of 505 digital panoramic radiographs taken from 227 males (45%) and 278 females (55%) aged 10 to 72 (40.1±12.9) years were evaluated. Elongated styloids were present in radiographs of 230 (45.5%) individuals. There was no significant difference in the ESP frequency between males (46.09%) and females (53.91%) (P=0.63). Type I and calcification B pattern showed more frequency than that of other categories.
According to these findings, elongated styloid process was a common condition among the studied population and had a significant correlation to the age.

Panoramic radiographs taken for dental purposes provide an opportunity for dentists to identify non-symptomatic maxillary sinus abnormalities. The aim of this study was to evaluate the frequency of mucous retention cysts (MRCs) of maxillary sinus and some associated risk factors in the patients attending to the dental faculty of Guilan. In this cross-sectional study, digital panoramic radiographs of patients referred to the department of radiology, dental school of Guilan, from October 2012 to October 2013 were evaluated. A total of 800 digital panoramic radiographs (200 for each season) were evaluated by one oral and maxillofacial radiologist to detect MRC in maxillary sinus. Frequency of MRC and some associated risk factors were assessed. Statistical analysis of the data was performed by Chi-square test. Among the 800 evaluated digital panoramic radiographs, 444 subjects were females (55.5%) and 356 were males (44.5%) aged 8 to 81 (36.02±14.71) years. The frequency of the MRC was 4% (32 radiograghs). Of 32 maxillary sinus MRCs, 13 (40.625%) were right-sided, 13 (40.625%) were left-sided and 6 (18.750%) were bilateral. Although, MRC presented no statistically significant correlation to age (P=0.444), the highest frequency was seen in fifth (6.1%) and third (4.7%) decades. Frequency in males (6.2%) was significantly higher than in females (2.3%); (P=0.005). The highest frequency of MRC was detected in spring (7.5%) and autumn (5%). In this study the frequency of MRC in males was higher than in females and was seen mostly single and unilateral. Also the highest frequency of MRC in spring might emphasize the effect of allergic factors on MRC prevalence, mentioned in some previous studies.

Pulp stone is a focal calcification in dental pulp which is commonly observed in usual dental radiographs and its clinical significance is difficulties to get access to the pulp chamber and root canal in endodontic treatment. So, this study was planned with the aim of determining the prevalence of pulp stone in patients referring to Guilan dental school and to assess its association with age, gender, tooth type, jaw, tooth status and systematic disease in this descriptive cross-sectional study, panoramic and bitewing radiographs of 373 patients referred to Guilan dental school were examined for the presence of pulp stones in the coronal portion of the pulp. Variables of age, sex and systemic disease were also recorded. Statistical analysis of the data was performed by chi-square test. The presence of pulp stone was detected in 20.9% of patients (13.9 female, 7% male) and 3.2% of the teeth. Gender and systemic diseases had no significant association with pulp stone (P>0.05).As age increased, the prevalence of pulp stones increased (P=0.025). Frequency of stone in maxilla was 56% and in mandible was 9% and the difference was significant (P=0.0001). The highest prevalence of pulp stones was in first molars of maxilla. The prevalence of pulp stone was significantly higher in sound teeth (P=0.0001). The results of the present study indicate that pulp stone is a frequent finding in molars and sound teeth and increases significantly with age. There is no significant association between pulp stone and gender or systemic disease.

The use of fast films is one of the major factors contributing to dose reduction. However، the diagnostic ability of fast film must be determined before current use of the films. The purpose of this study was to compare the efficiency of D and F speed films in the diagnosis of proximal caries. Eighty proximal surfaces in 40 extracted unrestored premolars were undergone radiography in standardized conditions using D- and F-speed flowdental intraoral films. True caries diagnosis was based on histological assessment of the surfaces after sectioning the teeth. Two observers read the radiographs using a four-point scale to record their diagnosis. Observer responses were evaluated using ROC analysis and areas under the ROC Curves (Az) was microscopical assessed by pairwise comparison of ROC Curve. D and F speed films had a mean Az of 0. 934 and 0. 920 respectively. The difference was not statistically significant (P=0. 548) Difference between observers was also not statistically significant. The efficiency of the new F-Speed films was not statistically different from that D Speed films in caries detection. This film shows the ability of reducing patient’s dose while maintaining diagnostic quality.

Radiographic evaluation of mineralization stages of third molars is a valuable and important criterion for age estimation in legal medicine. The pattern of dental development is hereditary and differs from race to race. Therefore, the aim of this study was radiographic evaluation of developmental stages of third molars based on chronological age in Gilani children and young people. In this descriptive, analytical cross-sectional study, 400 panoramic radiographs from Gilani patients with an age range of 6-22 years were evaluated and developmental stages of third molars were recorded by Demirjian method. The mean age of the subjects in every developmental stage was determined. The correlation between age and developmental stage was analyzed by Spearman's correlation coefficient. The differences between right and left sides, and upper and lower jaws were analyzed by Wilcoxon test and sex differences were analyzed by Independent t-test (p value < 0.05). Regression equations was obtained for age estimation (α = 0.05). The youngest age for observation of third molar bud was 6 and the oldest age was 11 in both jaws. There was a strong correlation between age and third molar developmental stage. There were no significant differences between right and left sides, but there were significant differences between upper and lower jaws. Comparison between males and females revealed significant differences in only the C stage of left mandibular third molars and A and E stages of left maxillary third molars. Within limitations of the present study, radiographic evaluation of third molar development in Gilani children and adolescents might provide a reference for age estimation.

Root resorption is one of the most difficult diagnostic problems in endodontic treatments. Since successful treatment depends on early diagnosis of this pathology, using several diagnostic methods such as radiographic Images based on films, digital images and finally advanced diagnostic techniques are important. Therefore, in this study, we compared digital detector (CMOS) and conventional films by changing the different variables in diagnosis of simulated external root resorption (RR). In this in vitro study, in the first group, twelve intact premolar teeth extracted for orthodontic treatments, were selected. On the root surface of each tooth, we created a 2×2 mm window on buccal, lingual or proximal surface in cervical or middle levels and covered the remaining parts of the teeth with nail varnish. The root resorption was stimulated using acid in two different steps. The radiographic images were taken by two detectors, conventional film and CMOS sensor in three angulations (ortho, 15 degree mesial shift and 15 degree distal shift) before and after resorption induction. In the second group, on another 12 premolar teeth, mechanical root resorption was created by bur in two different sizes. The above mentioned steps were repeated the same as the first step. The images were observed by an expert endodontist and radiologist to find out whether there was root resorption or not. The data were analysed by Chi square test. Overall, the rate of correct diagnosis of acidic resorption in digital method (CMOS) was significantly higher than that of conventional method; however, in mechanical resorption the difference was not significant. According to our study, digital radiographs are more effective and helpful than conventional images in diagnosis of external resorption.Variables such as size, shape of cavity, location and level of root resorption are effective in observers’ ability in detection of root resorption.

Finding an accurate and inexpensive method in measurement of bone width for determination of implant size is critical. Linear tomography is a cost effective method and there is no accurate finding about accuracy of linear tomography in evaluation of mandibular wide. The purpose of this study was to determine the accuracy of linear tomography in estimation of mandibular width. In this diagnostic study (estimation of one method), 23 sites of four dry mandibles were selected and marked at the crest with a metal ball markers. After linear tomography in these sites, the width of mandible in the superior border of inferior alveolar canal was measured. The mandibles were then sectioned. The Pearson's rank order correlation coefficient between linear tomography and real values was determined. Then with estimation of mean absolute differences by magnification factor, the percentages of errors in ±1mm error limits were determined. The regression equation was written for better determination of agreement rate between radiographic and real values. The percentages of errors in ±1 mm error limits were determined. The Pearson's rank order correlation coefficient between the linear tomography and real values was 0.813(P<0.0001). The mean absolute differences between the mandibular width in tomographic sections and real values was 0.3 mm (SD=1.13) and 56.5% of width measurements were within the ±1mm error limits. By the resulting linear regression equation 51.8% of tomographic values were located within the ±1mm error limits. Linear tomography in evaluation of mandibular width should be used more cautiously.

Abstract The goal of health physics is to prevent the occurrence of deterministic effects and to reduce the likelihood of stochastic effects by minimizing the exposure of patients and radiation workers during radiographic examination. Regarding to panoramic radiography is the most common radiograph in the head and neck region and thyroid gland is the most sensitive area and also the extensive variety in panoramic machines, this comparative study was designed. Comparison of skin absorbed dose in thyroid gland area of planmeca and cranex tome panoramic machines. In this in vitro study a dry skull and a Pocket ion-chamber dosimeter were used. At first, panoramic examination was done in different exposure conditions for small, medium, large and child patients in planmeca machine. After every exposure, the charge of dosimeter was read and recorded. These stages were repeated for Cranex Tome Machine. Then statistical analysis was performed by sample paired test with %95 confidence. In both panoramic machines, the highest mean thyroid skin dose was detected in large size patient and in the highest level of exposure factors. The mean values of doses were recorded 0.11 mSV in planmeca machine and 0.14 mSV in Cranex Tome machine. There was the least mean absorbed dose in child programs and 0.03 mSV in planmeca machine and 0.02 mSV in Cranex Tome machine. There was no significant statistical difference between mean absorbed doses in patients with different size in two panoramic machines There was no difference between two panoramic machines for thyroid skin dose .Child program reduced thyroid skin dose definitely in both systems.

One of the normal landmarks in panoramic radiograph is in upper portion of mandibular ramus, which is termed medial sigmoid depression. Prevalence of this normal finding may be variable in different skeletal classification. Because this area is thin, it may also increase the potential for complications in orthognatic surgery if this area is involved.

Comparing the prevalence of medial sigmoid depression in panoramic view of orthodontic patient based on facial skeletal classification was objective point of this study.

In this study, 465 panoramic and lateral cephalometric views of patients (Including 236 cl.I, 141 cl.II and 88 cl.III patients) before orthodontic treatment were evaluated. Planmeca 2002 EC Proline Panoramic Machine provided all of radiographs. Angle classification was done by some orthodontists through study of cephalometry and consideration of their patients’ clinical status. Then panoramic radiographs were evaluated to determine present or absent of finding of medial sigmoid depression on RT and LT sides and categorized this finding to“ Marked” and “slight” criteria.

According to present study, prevalence of this depression was more common in skeletal cl.II (RT: %38.8, LT %39) and cl.III patients (RT: %23.9, LT: %38.6) in comparison with cl.I group (RT: %21.6, LT: %26.7) thus this finding has relationship with facial skeletal abnormalities. There was no correlation between this finding and side of involvement. No significant statistical difference was observed between the radiographic criteria of this depression in different skeletal classification.

High prevalence of medial sigmoid depression in patient with skeletal problem and more needs to orthodontic surgery in these groups were The most important results of consideration and attention to this area before mandibular osteotomies for prevention of any side effects.