فهرست مطالب fatemeh ezoddiniardakani

Age estimation is an important issue in forensic medicine.Teeth are more resistant to changes than bones, so they are one of the main indicators for age estimation in forensic medicine. To determine the relationship between age and dental changes, the ratio of dental pulp/Tooth volume (PV/ TV) is one of the most appropriate indicators. The aim of this study was to determine  the correlation between PV/TV ratio and chronological age in canine teeth using CBCT images.

In this descriptive-analytical study, a total of 183 CBCT images were selected randomly from archive of images in an oral and maxillofacial radiology center. The images were imported into the 3D Slicer software as DICOM data. Pulp volume, tooth volume and their ratio were calculated. Data were introduced into SPSS 17. We used T-test, ANOVA, Pearson correlation coefficient and linear regression for data analysis.

The mean value of PV/TV ratio was not different significantly in relation to gender, teeth location (mandible and maxilla, right and left sides), but there was a significant difference in terms of age. Pearson correlation showed a significant negative relation between the age of the subjects and PV/TV ratio (R = -0.714). The results of regression analysis for all data and also for all of 6 age groups showed significant correlation only in the age groups of 15-19 and 50- 59 years old.  

The results of this study showed that there was an inverse and significant relationship between PV/TV ratio and chronological age.  Also, in the age groups of 15-19 and 50-59 years, it seems that regression model can be considered a reliable method to estimate age in Iranian population.

Ionizing radiation-absorbed doses is a crucial concern in Cone-Beam Computed Tomography (CBCT) and panoramic radiography. This study aimed to evaluate and compare the Entrance Skin Doses (ESD) of thyroid and parotid gland regions in CBCT and panoramic radiography in Yazd province, Iran.

In this cross-sectional study, 332 patients were included, who were then divided into two age groups (adult and pediatric) and underwent dental CBCT and panoramic radiography. Twelve Thermoluminescence Dosimeters (TLD- GR200) were used for each patient to measure the ESD of thyroid and parotid glands. The differences between the ESD values in CBCT and panoramic examinations as well as between the adults and children groups were evaluated by one-way ANOVA and Man-Whitney tests.

The mean and Standard Deviation (SD) values of ESD in panoramic imaging were equal to 61 ± 4 and 290 ± 12 µGy for the thyroid and parotid glands of the adult groups, respectively. Notably, these values for CBCT were significantly higher (P<0.01), as 377 ± 139 and 1554 ± 177 µGy, respectively. Moreover, the mean ESD values in the panoramic examination were 41 ± 3 and 190 ± 16 µGy for thyroid and parotid glands for the children group, while they were 350 ± 120 and 990 ± 107 µGy in CBCT (P<0.01), respectively. The ESD values in the parotid gland were approximately 3.4 (2.8-4.1) and 4.7 (4.6-4.8) times greater than those for CBCT and panoramic examinations, respectively.

Although CBCT provides supplementary diagnostic advantages, the thyroid and parotid glands’ doses are higher than panoramic radiography. Therefore, the risks and benefits of each method should be considered before their prescription.

This study aimed to determine the Entrance Surface Dose (ESD) of sensitive organs in Cone-Beam Computed Tomography (CBCT) imaging of the maxillofacial region in the two age groups of adult and pediatric.

In this work, the measurements were performed using Thermo Luminescent Dosimeters (TLD-GR200). The imaging was performed using a PROMAX 3D CBCT scanner for 30 adults and 20 pediatric patients. The ESD value for each patient in the region of eyes, thyroid, and parotid glands was measured by 15 TLDs during CBCT of maxillofacial.

The highest and lowest mean values of ESDs were related to the parotid and thyroid gland regions in adults, 4.77 ± 0.61 mGy and 0.37 ± 0.16 mGy, respectively. In addition, these values were obtained 2.97 ± 0.36 mGy and 0.35 ± 0.12 mGy in pediatric groups as the highest and lowest values in that order. The results showed that the ESD values of the parotid gland regions in maxilla and mandible examinations had a significant difference (P <0.05). In addition, there was a significant difference between the ESD values of the parotid gland regions among the adults and pediatric groups (P <0.05).

According to the results, the ESD values in both age groups were higher in the parotid gland region during maxillofacial CBCT examinations. Therefore, it is recommended to set radiation parameters like mAs as low as possible for reducing the patient dose, especially pediatric patients due to the more sensitive organs.

One of the fractal analysis methods to examine the structure of a texture is fractal dimension (F.D.) measurement. F.D is a quantitative method to show the complexity of a structure using a number. The aim of this study was to determine the effect of different exposure conditions, voltages and angle of x-ray tube on F.D. values of mandibular bone.

This lab-trial analytical research was conducted on ten healthy, non-fracturing human mandibles. Periapical digital images were obtained by the Peri-Apical Focus (Planmeca, Finland) with a constant time of 0.2 seconds and changes in exposure conditions and angle of the tube. Periapical radiographs were obtained with 2 kV voltages of 60, 70, with2 mA of 400, 500, and 3 tube angles of -5, 0, +5 degrees. Data was analyzed by SPSS version 16 software  and Kolmogorov–Smirnov test, mann whitney testand ANOVA test.

No significant difference was observed in fractal mean values between 60 and 70 kVp and among 5-, 0, 5+ degrees in all 10 mandibles.There was a significant difference between the 400 and 500 mA just in one case (p≤0.05).

Considering the incompatibility of the amount of calculated fractal dimension from kVp, mA and tube angle, this method can be used as a useful tool in dentistry to examine the structure of spongy bone and its changes in various pathological conditions. Then, standardize the periapical imaging technique to compare it is not necessary.

Health of periapical tissues has been considered as an index for the evaluation of endodontic outcomes. The present study sought to assess the pattern of periapical lesion extension in anterior teeth using cone-beam computed tomography (CBCT). Methods and Materials: In this descriptive study‚ 199 CBCT images belonged to patients aging from 15 to 79 were assessed according to periapical lesion extension in the regions of maxillary and mandibular anterior teeth. Maximum periapical lesion extensions in three orthogonal planes were measured and recorded in millimeters and were assessed according to age‚ gender‚ dental arch and tooth type. Statistical analysis was performed using percentages‚ repeated measure ANOVA and Bonferroni tests. The significant level was set at 0.05.

The highest average of lesion extension, in both maxilla and mandible, was in vertical dimension‚ followed by horizontal buccolingual and horizontal mesiodistal dimensions‚ respectively. There were significant differences between the vertical and mesiodistal (P=0.004) and also mesiodistal and buccolingual (P=0.010) periapical lesion extension dimensions. In addition, there were significant differences in maxilla and mandible (P=0.012). In maxilla, there were no significant differences between the three tooth types (P=0.346) but in the mandibular arch, there were significant differences between central-canine (P=0.004) and lateral-canine (P=0.026). According to independent variables, only gender had a significant effect on the lesion extension in anterior regions of maxilla and mandible (P=0.001). The periapical lesion extensions were significantly higher in men compared with women.

The bone destruction_as a consequence of periapical inflammatory process_ was greatest in the vertical, and lowest in the horizontal mesiodistal dimensions. That way, the extension in buccolingual dimension, which could not be detected in the 2-D imaging techniques, was rather high in the present study. Thus CBCT, as a 3-D imaging technique, could be recommended for the precise evaluation of lesion extension in the periapical area.

The retromolar canal is an anatomical variant that needs consideration in local anesthesia and surgical procedures involving the retromolar area. Complications such as local anesthetic insufficiency, a sensory deficit, hemorrhage and traumatic neuroma may arise in the absence of recognition of these variants. The aim of this study is to determine the prevalence and course of retromolar canal in the Iranian population.

This study is a descriptive cross sectional study. The cross sectional sagittal and three dimensional images from volumetric CBCT. data of 270 patients were reconstructed using on demand imaging analysis software. Retromolar canals were classified into two types according to the courses. The width and location (distance from the third molar) of retromolar canals were evaluated. Results were analyzed with SPSS 20 software and were assessed using the t_test and chi_square test.

Retromolar canal was observed in 9/25 % of patients. The mean width of the retromolar foramen was 1/43 mm, and the mean distance from anterior border of retromolar foramen to the distal CEJ of the second molar was 13/33 mm.

The prevalence of retromolar canals in the Iranian population was lower than that was reported in previous studies. It can be observed in 9/25 % of Iranian patients. Damage to the retromolar canal may be unavoidable during surgical procedures may result in paresthesia, excessive bleeding, postoperative hematoma, or traumatic neuroma. Therefore, the clinician must pay particular attention to the identification of a retromolar canal by preoperative radiographic examination and additional CBCT scanning is recommended.

The identification of people with carotid calcified atheroma is an important measure to reduce the incidence of brain stroke. The aim of this study was to evaluate the frequency of carotid artery atheroma in post-menopausal women in panoramic radiographs.
In this descriptive cross-sectional study, 151 panoramic radiographs from women aged 45 years and above that referred to the Radiology Department of Yazd Dental School during 2016-17, were selected by convenience sampling method. Radiographs were examined by PlanMeca 2002 EC proline panoramic digital machine. In radiographs, the presence or absence of carotid calcified atheroma was investigated and cases with differential diagnosis of atheroma were excluded. Patient's tomography data were recorded in a questionnaire and the collected data were analyzed by SPSS20 software and Chi-square test.
Resultus: In this study, 151 panoramic radiographs evaluated, 69 samples (45.7%) had carotid artery atheroma in radiography, and the largest view 40 samples (26.5%) were bilaterally.
The more time passes from the menopause of patients,the more they become involved with carotid artery calcification. That means carotid atheroma has a significant relationship with the number of years pass from menopause.

Presence of external root resorption in second molars associated with impacted mandibular third molars was not rare. The neglect of this issue may leads to penetration of the pulp and loss of the second molars. The aim of this study was to investigate the incidence and risk factors affecting the external root resorption in second molars associated with mandibular impacted third molars were inclined mesially and horizontally by Cone Beam Computer Tomography (CBCT) images.
In this cross sectional study the samples consisted of 231 scans with mesially and horizontally impacted mandibular third molars. Incidence of external root resorption of second molars and the effects of age, gender and clinical parameters such as location and intensity of external root resorption were considered. Moreover, depth and inclination of impacted mandibular third molar were evaluated by CBCT. The data were analyzed by Chi-square test.
The overall incidence of external root resorption in the second molars was 22.08%. Incidence of external root resorption in second molars was significantly related to gender and inclination of third molar. The relations between external root resorption and impaction depth of third molar or the patient's age was not statistically significant. However, the relationship between external root resorption and the intensity or depth of impacted third molar and location of root resorption was statistically meaningful.
Patient’s gender and horizontal inclination of third molars are the most important factors affecting the presence of external root resorption in the second molars associated with mesially and horizontally impacted mandibular third molars.

This study sought to assess the relation of mandibular cortical index (MCI) with age, gender and gonial angle size in an Iranian adult population using digital panoramic radiography.
We evaluated 370 digital panoramic radiographs of patients and divided them into five 10-year age groups. Each radiograph was assigned to low (≤120°) or high (≥125°) angle groups in terms of the gonial angle size. The MCI class was also determined for each individual. The multinomial logistic regression was used to assess statistical differences.
The MCI class was significantly different between males and females and MCI class 3 had higher prevalence among older individuals. There was no statistically significant difference in distribution of MCI classes between individuals with high and low gonial angles.
Age-related changes in MCI support its potential use for detection of skeletal osteopenia.

The aims of this study were to test whether lightening of the overexposed radiographs improve determination of endodontic files length and whether lightened radiographs are comparable with ideally exposed radiographs. Four dried human skull coated with soft tissue-equivalent wax used for exposing radiographs of the upper molars. First, the endodontic file was placed in full length of the root and four series of radiographs obtained. The time to expose the first series was unchanged (standard group) but increased for the other three series. Two series of overexposed radiographs set as test groups (one lightened with copper sulfate reducer and the other lightened with sodium hypochlorite) and one series set as control group. Then the endodontic file placed 2mm short in the root and four series of radiographs obtained like the former. A viewer evaluated radiographs. ROC curves were obtained and areas under the curves were calculated. Sensitivity, specificity and Cohen’s kappa was calculated. The average area under ROC curves was 1, 0.995,1 and 0.643 for the standard, Copper sulfate, sodium hypochlorite and the control group, respectively. Sodium hypochlorite show a better performance in terms of sensitivity and specificity compared to Copper sulfate. Differences between the test radiographs and standard and control radiographs were significant (p<0.05), but not between Copper sulfate lightened radiographs and control radiographs (p=0.784). Lightening with NaOCl is a cheaper and less cumbersome method which need only one minute to correct the radiograph.

Introdouction:The styloid process(SP) has the potential for calcification and ossification. The aim of this study was to investigate the prevalence of different patterns of elongation and calcification of the SP. In this cross-sectional study, 400 digital panoramic radiographs taken for routine dental examination in the dental school of Shiraz University were evaluated for the radiographic features of an elongated styloid process (ESP). The apparent length of SP was measured with Scanora software on panoramic of 350 patient who met the study criteria, (204 females and 146 males). Lengths greater than 30mm were consider as ESP. ESP were also classified into three types based on Langlais classification (elongated, pseudo articulated; and segmented). Data were analyzed by the Chi squared tests and Student’s t-tests. ESP was confirmed in 153 patients including 78 males and 75 females (43.7%). The prevalence of ESP was significantly higher in males. 53.8% of males and 36.8% of female patients has ESP (P value < 0.05). ESP was also significantly more common in the older age group (p < 0.05). There was no statistically significant difference between the occurrence of unilateral and bilateral ESP (p > 0.05).Type I and Type II ossification pattern had almost equal frequency (42.5% and 43.8% respectively) ESP and calcification of stylohyoid ligament can be easily detected in panoramic radiograghs and is more common in older patients.

This study was aimed to investigate the use of panoramic radiography in patients with low bone mineral density (BMD) in order to diagnose and prevent osteoporotic fractures. Panoramic radiographs of 60 patients (20 men and 40 women) aged from 40 to 70 years with cortical thicknesses of less than 3 mm in the mandibular angle were selected from patients referred to a dentomaxillofacial radiology clinic and were then examined for mandibular cortical angles. These were measured using Computed Radiography (CR) software. The bone densitometry was carried out using Dual Energy X-ray Absorptiometry (DEXA). Cortical thicknesses at the lower border of the mandibles were also measured by panoramic radiographs. Statistics analyses were then undertaken using Fisher’s exact test، Chi-square، t-test، ANOVA and receiver operating characteristic (ROC) curve. In most cases، no significant difference in mandibular angle cortical thickness was found between those patients with a normal BMD and those patients with a lowered BMD (P=0. 621). There was a relationship between the cortical thicknesses of the mandibular lower border، and vertebral and femoral BMD (P<0. 0001)، and there was a significant difference between the thickness of the mandibular lower border and BMD. The results of this study also revealed a new marker of osteoporosis on the mandibular lower border under the third molar. A thickness of 2. 80 mm of the mandibular lower border was detected as a threshold for the measurement of bone densitometry in the chosen Iranian population. Panoramic radiography is effective for screening patients who are at risk of having decreased bone mineral density. Patients with a threshold of 2. 80 mm thickness of the mandibular lower border should be considered as individuals likely to have osteoporosis associated low bone density.

Scaphoid fractures are the most common type of carpal fractures.. The aim of the study was to compare the diagnostic value of panoramic and conventional radiographs of the wrist in scaphoid fractures..Patients and The panoramic and conventional radiographs of 122 patients with acute and chronic wrist trauma were studied. The radiographs were analyzed and examined by two independent radiologist observers; one physician radiologist and one maxillofacial radiologist. The final diagnosis was made by an orthopedic specialist. Kappa test was used for statistical calculations, inter- and intra-observer agreement and correlation between the two techniques.. Wrist panoramic radiography was more accurate than conventional radiography for ruling out scaphoid fractures. There was an agreement in 85% or more of the cases. Agreement values were higher with better inter and intra observer agreement for panoramic examinations than conventional radiographic examinations.. The panoramic examination of the wrist is a useful technique for the diagnosis and follow-up of scaphoid fractures. Its use is recommended as a complement to conventional radiography in cases with inconclusive findings..

Elongation and calcification of the stylohyoid apparatus is probably related to Eagle's syndrome and may cause such symptoms as facial pain and dysphagia in patients. In the present study, the relationship between serum calcium level and stylohyoid apparatus length was studied in adults referring to the dental college of Yazd. This was a cross-sectional descriptive study on 50 adult patients above 20 years old (28 men, and 22 women) referring to the radiology ward of the dental college. The stylohyoid ligaments were measured from the base of the skull to the bony tip of each appendix by panoramic radiograph. Mineralization of the ligaments more than 30 mm on the panoramic radiographs was considered abnormal. The serum calcium level of all patients was then measured. Data were analyzed by t-test and Pearson's correlation analysis. Mean length of the stylohyoid apparatus was 27.36 ± 9.10 mm and was not related to age and sex. An elongation rate of 26% was obtained. The mean serum calcium level was 9.39 ± 0.57 mg/dl and there was not a statistically significant difference in serum calcium level between various age groups and genders. There was no relationship between the length of the stylohyoid apparatus of each side and serum calcium concentrations in different age groups. It appears that the length of the stylohyoid apparatus is not related to serum calcium level within our patient population.

Background and aims. The aim of the present study was to compare the effect of application of an image processing mode of a colorizer on the efficacy of the detection of interproximal carious lesions viewed in direct digital radiography.Materials and methods. A total of 102 proximal surfaces of extracted human premolars on direct digital images were evaluated by three observers with and without the application of pseudocolor filter. The teeth were sectioned and viewed microscopically to determine the gold standard. The kappa value agreement ratios were calculated.Results. Sensitivity and specificity values for normal digital and colorized images were 66.7%, 60%, 80.5%, and 50%, respectively. However, there were no statistically significant differences between the two types of images (P = 0.12).Conclusion. In this study application of pseudocolor filter on digital radiographic images failed to result in significantly improved caries detection.

Background and aims. Inferior alveolar nerve block injection is one of the common intra oral anesthetic techniques, with a failure rate of 15-20%. The aim of this study was to evaluate the position of the lingula as an index for this injection.Materials and methods. Thirty eight panoramic radiographs of 7–11 year old patients were analyzed and the distance between the lingula index and occlusal plane was measured. Then, lower alveolar nerve block injection was performed on 88 children. Finally, a visual analogue scale was used to measure the rate of pain in the patients.Results. This distance increased with age and in children younger than nine years is −0.45 mm on the right side and −0.95 mm on the left side. This distance in children older than 9 years is −0.23 mm on the right side and 0.47 mm on the left side.The success rates of inferior alveolar nerve block injection based on lingual index were 49% on the right side and 53.8% on the left side. Conclusion. As the lingual index has various positions and its distance from the occlusal plane increases with age, it is not an appropriate landmark for inferior alveolar nerve block injection.

Background and aims. While the use of X-ray is increasing, professional responsibility of dentists entitles them to have sufficient and correct knowledge of using radiographs. The aim of this study was to assess the level of knowledge of correct prescription of radiographs among dentists in Yazd, Iran. Materials and methods. This was a descriptive cross-sectional study including 134 general dentists and dental specialists. A self-administered questionnaire was used to assess their level of knowledge in various sections pertaining to prescription of radiographs. Their level of knowledge was compared in each section on the basis of gender and educational status. Results. Participants showed a high level of awareness in prescription of panoramic, periapical radiographs, and computerized tomography, whereas it was moderate in the field of occlusal radiographs, susceptible patients to caries, patients with periodontal diseases, evaluation of growth condition and dental crypts and weak in the fields of bitewing radiographs and insusceptible patients to caries. There was no difference in level of knowledge between genders. The level of knowledge in specialists was higher than general dentists except for using X-ray for susceptible patients to caries where no significant difference was observed.Conclusion. Specialist dentists were more knowledgeable than general dentists in prescribing radiological examinations.

Despite quite a lot of risks resulting from repetitious radiographies, supervision on dental radiographie's repetition may serve as custody against radius. The aim of this study was to investigate the causes for repeating periapical radiography in radiology department of school of dentistry and the effect of education on repeatition reduction in Yazd University of Medical Sciences. This descriptive analytical study performed as quasi-experimental (before and after) trial. After patient's referral to department of oral and maxillofacial radiology, radiographies taken by students having faults were gathered in a place and once again the films were given to students. Among the erroneous graphs in the middle of the semester, 300 graphs were randomly selected and investigated. 15 cases for technical errors and 13 cases for developmental faults were recorded separately in tables. In midterm, the causes for faults taken place were discussed and students were fully educated on methods for avoiding these failures attending in radiography room and darkroom. After this educational period the process was repeated and at the end of the semester, 160 defected films were investigated and recorded in previous tables. Data was analyzed using t-test, Z, chi², Fisher exact test, and McNamara. All observed errors before intervention were 577 types and the failure mean was1.92 in each film. Only 350 films were repeated after intervention that among 160 selected samples, 169 faults were recorded and failure mean turned to be 1.05 in each film and the difference is significant. Performing this educational intervention reduced the rate of erroneous graphs by more than 60 percent. The frequency of failure repetition also showed a significant difference before and after intervention. Error reduction in radiography repetition resulting from education is evident but it seems despite complete education in theoretical courses, the causes for repeating radiography films should be investigated suspiciously and continual education should be given to students in radiography room and darkrooms. It may reduce superfluous and unnecessary radiographies, decrease radiation process and observing rules on safekeeping against it, lessen the time spent and patient's dissatisfaction, and decline the heavy costs of film and developmental processing material in educational centers.

Candida Albicans (CA) is by far the most common yeast of oral infections, including endodontic infections. The aim of this study was to evaluate and compare the antifungal effect of white-colored mineral trioxide aggregate (WMTA) and Portland Cement (PC) using a tube-dilution test. WMTA and PC were tested freshly mixed and after 24 h. The experiment was performed in 24-well culture plates. Fifty wells were used and divided into four experimental groups (freshly-mixed WMTA freshly-mixed PC, 24 h-set WMTA, and 24 h-set PC) of 10 wells each and control groups of five wells each. Plates of Sabouraud dextrose agar mixed with CA served as positive control and Sabouraud dextrose agar without CA served as negative control. Fresh inoculate of CA was prepared by growing an overnight culture from a stock culture. Aliquots of CA were then taken from the stock culture and plated on the agar compound of the experimental and control groups. All plates were incubated at 37°C for1h, 24 h, and 72 h. Growth of fungi was monitored daily by the presence of turbidity. Kruskal-Wallis test was used for data analysis. Findings showed that in the freshly mixed as well as 24 h-set WMTA and PC, fungal growth was observed during 1 h incubation; whereas by increasing the incubation time, no fungal growth was observed in 24 h and 72 h. It was concluded that WMTA and PC (freshly mixed and 24-h set) were effective against CA.

In dental radiography, there are specific potentials to transmit infection. The goal of this research was to investigate radiographic films and tubes microbiologically in private and pudic dental radiographic centres in the city of Yazed. In this cross-sectional descriptive study (2001), all 13 public and private centres with totally 21 dental radiography machines were investigated. First, sample was collected from different areas of radiography tubes and film's covers by a sterile wetswap. All samples were kept in Tayoglycolate culture media and then put in 37˚C incubator in microbiology laboratory. The cloudiness was checked every 24 hours. Data were analyzed using Extended Fisher test. In samples collected from public radiography centres, microbial infections with pseudomonas aeruginosa, Staphylococcus epidermidis, Aspergillus niger and alkagenous were detected probably resulted from hospital infections and healthy carries among hospital personnel. In private centres infections with microbes such as Neisseria sicca, Staphylococcus epidermidis and Bacillus subtilis were detected, a probable consequence of normal flora in the environment. Film's covers in public centres were infected with Staphylococcus aureus, staphylococcus hemolyticus, Neisseria sicca nd Staphylococcus epidermidis probably due to contact with healthy carriers.. The methods applied in Yazed radiographic centres, especially the public ones, are completely different from the standards recommended by ADA and CDC. Therefore, our society is definitely exposed to cross-sectional infections along radiographic clinics.