[Comparison of skin absorbed dose in thyroid gland area of Planmeca and Cranex Tome panoramic machines]

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 machines and 0.14 mSV in Carnex 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

[Evaluation of the impaction pattern of the third molar teeth in an Iranian population]

Statement of Problem: Impaction of the third molar teeth is common. Due to the probable complications resulting from tooth impaction and the effects of the impaction pattern on treatment plan, the evaluation of this pattern is important

Purpose: This study aims at evaluation of the impaction pattern of the third molar teeth and its relation with the depth of impaction

Methods and Material: In this descriptive study, panoramic radiographs of 409 patients aged 20-40 years old who referred to Dental Clinic of Guilan University in a two-year period were chosen. The depth of impaction was evaluated according to the relationship between the Cementoenamel Junction [CEJ] of the third molar tooth with the alveolar crest. Winter classification was used for detection of the angulations of the impacted teeth. Pearson Chi square test was applied for data analysis

Results: There were 44.7% males and 55.3% females in this study. Evaluation of the impaction depth showed that the most frequent impaction level was level C in the maxilla, and it was level B in the mandible. In the maxilla, 47.5% and in the mandible, 41.2% of the impacted teeth were found in the male patients. The maximum and minimum frequency of different kinds of impaction angulations was vertical [67%] and horizontal [0%] in the maxilla. In the mandible, it was mesioangular [57.3%], distoangular [1.1%], respectively. In the evaluation of different impaction angulations based on the impaction depth, most of the vertical and mesoangular patterns of the impacted teeth were accompanied with level C and level B, respectively

Conclusion: There was no difference between female and male patients for frequency of the impacted teeth in the maxilla and mandible. Distribution of the angular pattern of impaction was different in the maxilla and mandible. There was no significant difference between the frequency of impaction angulations in different impaction levels

[Comparison of radiographic findings between mandibular asymmetric and symmetric patients]

By considering the extensive dimensions of asymmetry, it seems that the evaluation in a single radiographic view is not adequate and it is better to evaluate it through different aspects. To compare the radiographic findings of patients with mandibular asymmetry and normal subjects, and to define the asymmetry index in this group of patients. In this descriptive case-control study, Posterior- Anterior PA cephalometric, panoramic and condylar tomographic views of twenty patients, including 10 asymmetric patients with the mean age of 17.8 years [6 female, 4 male] and 10 symmetric subjects with the mean age of 17.6 years [6 female, 4 male] were evaluated. The control and experimental groups were matched by Cervical Vertebra Maturation Stage index and nearly chronological age. In PA cephalometry radiographs, 8 indices were evaluated in two categories of horizontal indices and vertical indices. After measuring condylar and ramal heighs in panoramic views, condylar and ramal indices were determined. In tomograms three images comprising of posterior, middle and Anterior were obtained from right and left sides. The average of maximum medio lateral dimension of condyle was calculated as tomographic index. Paired sample test analysis using SPSS V[10] with%95 confidence interval is applied for analysis. Mean tomographic indices in control and cases groups were reported 2.91 and 4.98 respectively. Condylar and ramus indices in control group were 0.07 and 0.01, and in case group, were 0.04 and 0.01. There is no significant difference between experimental and control groups on all of the mentioned radiographic indices. Tomography, PA cephalometry, panoramic and tomography views are helpful in the diagnosis of asymmetry. But they don't introduce a definitive borderline in the form of asymmetry indices

[Agreement of panoramic radiography and doppler sonography in detection of carotid artery calcification]

According to some studies, diagnosis of carotid artery calcification in panoramic radiography could be a good marker and an aid for the prediction and prevention of cerebrovascular and cardiovascular accidents. Doppler sonography is an important diagnostic method for the recognition of calcified atheroma and carotid artery stenosis, With respect to the importance of the recognition of calcified atheroma and vast usage of panoramic radiography in dental treatments, the purpose of this study was to evaluate the degree of agreement between panoramic radiography and Doppler sonography in the diagnosis of calcified carotid artery. In this descriptive-analytic study, panoramic radiographs were taken from 35 nephrologic and neurologic patients with carotid Doppler sonography, in order to evaluate calcified carotid atheroma. Panoramic radiographs were designed in a form that, the most of cervical vertebrae height to the level of the 4[th] and 5[th] intervertebral spaces, could be seen. The data related to the presence or absence of calcified atheroma in Doppler sonography and panoramic radiography were collected by SPSS software. The degree of agreement between the two methods was evaluated by Kappa analysis. Panoramic radiograph and Doppler sonography in both male and female patients in right side showed an average to good agreement rate. Overall, this agreement in patients with cerebrovascular complications without paying any attention to the affected side was from good to average degree. The presence of linear and nodular opacities in the level of 3[rd]-4[th] or 4[th]-5[th] intervertebral spaces in panoramic radiography especially at the right side could be considered serious. If positive risk factors are also present, the patients could be referred, with great confidence and economical justification, for precise medical examinations, [Doppler Sonography]

[In vitro survey of the role of spiral tomography in measurement of distance from crest to mandibular canal]

Introduction: Following the teeth loss, the changes in the shape and angulations of alveolar ridge happens Tomographic images can be helpful for providing the sufficient details about vertical and horizontal dimension of alveolar bone, situation of vital and anatomic structures, and deduction of surgical injuries

Objective: Considering the importance of spiral tomography in determination of mandibular canal and vertical height of alveolar ridge, we decided to use this advanced method in evaluation of the alveolar bone height from crest to mandibular canal

Materials and Methods: Three dry human mandibles were selected in this analytical study for comparison of tomography and real measurements. Cross-sectional tomographic slices with 2 mm thickness ware taken at three or four different locations distal to the mental foramen by means of Cronex Tome unit [Sordex, Helsinki Finland] in each side. These sites marked by gutta-percha filled pits. On tomographic image, a line was drawn from crest to the inferior border of mandible [MC] and the distance from crest to mandibular canal was measured on MC line. Meanwhile the distance from the crest to mandibular canal was measured. Subsequently, vertical sections were provided at the sites marked by gutta- percha, perpendicular to the lower border of the mandible by special disk .The real anatomical bone height, after estimation of magnification factor 1.5 were compared. SPSS software [version No 11.5] and sign test analysis were used in order to evaluate the statistical details

Results: In measurement of the distance between crest to mandibular canal, showed no significant difference between tomographic measurements and real dimensions. Measuring height in tomography indicated an underestimation ranging 3.7 to 0.07

Conclusion: This point that there is an underestimation in measurement of height justifies the safety of spiral tomography in estimation of distance from crest to mandibular canal. Which itself prevents serious injuries to neurovascular bundle

[Frequency of retention cyst of maxillary sinus in panoramic radiography]

Introduction: Diagnosis of sinus retention cysts indicates inflammatory reaction in sinuses and in attention to its reports in different geographic sites; we decided to survey its frequency in panoramic radiography. Because it doesn't have the limitation of waters' view in detection of small lesion in antral floor due to superimposition of molar roots and petrous bone in this area and it can be used as a routine radiography in dentistry

Objective: This study was designed to determine the frequency of retention cyst in panoramic view in Rasht-Iran from the beginning of winter of 2003 to 2004

Materials and Methods: Two maxillofacial radiologists assessed 1422 panoramic radiographs, which were taken by Planmeca EC Proline machine together during one year. Absence or presence of this lesion, number of these cysts and location of antral wall involvement were defined. Data collections were organized on sex, age and months of radiography taking. SPSS analysis software, chi-square test and t-test were used for statistical analysis

Results: Frequency of retention cyst was 4% and it was more in males than females. Ninety percent of this antral lesion was single and 10% had multiple forms. The most common location involved was antral floor. June and January were the most common months of retention cyst presentation in Rasht in panoramic views

Conclusion: In our study, frequency of antral cyst was higher than previous studies. Temperature fluctuations, inflammatory and allergic factors in different months are effective factors in higher presentation of retention cyst in this geographic region. Antral floor involvement in single form and retention cyst presentation in male more than female are the most important notes of this study

[Rate of agreement of panoramic and water's view in diagnosis of zygomatic complex and inferior orbital rim fractures]

Evaluation of facial skeletal trauma is based on clinical and radiographic examinations. For many years, conventional radiographs have been used in diagnosis of fractures. Today, advanced techniques such as CT and 3D-CT gradually are used as complementary techniques for conventional methods. Panoramic radiography is one of these conventional radiographs which cover maxilla, mandible, zygoma and sometimes inferior orbital rims. "Water's views" is the specialized radiographic technique of zygomatic bone and orbital rims in diagnosis of facial fracture. To determine the agreement of panoramic radiographs with water's views in detection of zygomatic complex and inferior orbital rim fractures In this descriptive-analytical study, 58 panoramics and water's views of patients with maxillofacial trauma were selected. These radiographs were coded and an experienced maxillofacial radiologist expressed about the presence or absence of fracture in maxillary process of zygomatic bone, inferior orbital rims, temporal process of zygoma, lateral wall of maxillary sinuses and zygomatic arch. The patients' demographic information was gathered by SPSS version 11.5. Kappa analysis test was used for calculation of the agreement rate between two radiographs Pvalues < 0/05 was regarded as significant. Water's and panoramic views had the most agreement rate of very good to ideal level in diagnosis of fracture of maxillary process of zygoma [p<0.001, K=0.76]. The agreement rate in diagnosis of fracture of temporal process of zygoma, inferior orbital rim and lateral wall of maxillary sinuses was in medium to good level but the agreement rate in diagnosis of zygomatic arch fracture was the least. According to the results of this study, the panoramic findings must be taken seriously in diagnosis of the fracture of maxillary process of zygoma and inferior orbital rim. The importance of this view must be considered in diagnosis of mid facial fracture especially in traumatic patients due to widespread coverage of facial bones

Evaluation of the relation between adenoids hypertrophy and cranial base angles

Adenoids are normally large in children and their size starts to reduce during adolescence. Hypertrophic adenoids could be associated with allergic reactions. Enlarged adenoids result in nasal breathing difficulties and the child is forced to switch to mouth breathing. Airway obstruction causes postural alterations of jaw, tongue and head, and due to persistent obstruction, patient's appearance changes to adenoid face. Evaluation of nasopharyngeal space in lateral cephalometic view is a simple and repeatable method for determination of the size and shape of adenoids and nasopharyngeal space which can provide a simple measurement of nasopharyngeal obstruction. The roof of nasopharyngeal space is covered by the sphenoid bone. Thus changes of nasorespiratory resistance by hypertrophic adenoids may affect the cranial base angles. In this study, the relationship between adenoid hypertrophy and cranial base angles was investigated. In this descriptive-analytic study, lateral cephalometric views of 7 to 14 y/o patients from the files of orthodontic centers in Rasht city were selected. The radiographs with proper resolution were separated for this research. Adenoid to nasorespiratory ratio [A/N Ratio] was determined by Fujioka method and categorized in three groups: A [A/N< 0.8], B [0.5