Relationship between Impacted Mandibular Third Molars and the Mandibular Canal on CBCT Scans.

This study aimed to assess the relationship of impacted mandibular third molars with the mandibular canal on cone beam computed tomography (CBCT) scans. This cross-sectional study was conducted on CBCT scans of 137 patients with 204 impacted mandibular third molars. The relation of age, gender, class of impaction, anatomical position of canal relative to tooth (buccal, lingual, inferior, inter-radicular), tooth angulation (mesioangular, vertical, distoangular, horizontal), relationship of tooth with the mandibular canal (no contact, in contact, relation), relationship of tooth with the mandibular cortex, anatomical site of contact of tooth with the mandibular cortex (buccal, lingual, inferior), and the impression of canal (grooving, no effect) on impacted teeth were evaluated. Data were analyzed using one-way ANOVA, Chi-square test and Fisher's exact test. Class B of impaction (78.9%), inferior position of canal relative to the impacted tooth (53.9%) and mesioangular angulation (53.4%) had the highest frequency, respectively. The relationship of tooth with the mandibular canal was "relation" in most cases (53.4%) followed by no contact (26.9%) and in contact (19.6%). Significant associations were noted between depth of impaction (P < 0.001), tooth angulation (P = 0.024), anatomical position of canal relative to tooth (P < 0.001), relationship of tooth with the mandibular cortex (P = 0.032) and anatomical site of contact of tooth with the mandibular cortex (P = 0.013) with the impacted tooth-mandibular canal relationship. CBCT provides accurate information about the relationship of impacted third molars with the mandibular canal and can decrease the risk of traumatization of inferior alveolar nerve (IAN) during their surgical extraction.

The Effect of Changes in the Angular Position of Implants on Metal Artifact Reduction in Cone-Beam Computed Tomography Images: A Scoping Review.

Objective: Dental implant artifacts can compromise the quality of cone-beam computed tomography (CBCT) scans and challenge radiographic detection in surrounding regions. This literature review was conducted to examine the impact of implant angle modification on reducing metal artifacts in CBCT scans. Materials and Methods: A scoping review of literature was carried out in PubMed, Embase, Scopus, and Cochrane databases. Results: Different spatial planes, including alpha, beta, gamma, and phi, along with 0°, 5.2°, 9.8°, 14.5°, 15°, 30°, 45°, 60°, 75°, and 90° angles were studied. Changes in the angular position of implants may reduce metal artifacts and improve the quality of CBCT scans. Conclusions: Rotating implants within the alpha plane and angling them at 90° in the alpha plane enables reducing dental implant artifacts.

Cone Beam CT Analysis of Haller Cells: Prevalence and Relationship with Orbital Floor Dehiscence.

Materials and Methods: CBCT images of 120 patients were interpreted in coronal plane for the presence of Haller cells and orbital floor dehiscence. The prevalence of Haller cell, presence of dehiscence, unilateral, or bilateral frequency were assessed. In addition, the size was categorized in three groups of small, medium, and large. Chi-square and Cochran-Mantel-Haenszel tests were used for statistical analysis of the data, and p < 0.05 was considered to be significant. Results: A total of 51 male and 69 female with mean ± SD age of 38.84 ± 68.14 were assessed. The overall prevalence of Haller cells was 56.7%, of which 44 (64.7%) were unilateral and 24 were bilateral (35.3%). The majority of the cells (70.7%) were seen in medium (2-4 mm) sized. There was a significant association between Haller cells and orbital floor dehiscence (p ≤ 0.001). Conclusion: The prevalence of Haller cells was remarkably high and the presence of Haller cells was strongly associated with ipsilateral orbital floor dehiscence. Based on the findings of this study, CBCT can be useful in delineation of the bony anatomy of sinonasal complex.

Relationship of Vitamin D Deficiency with Cervical Vertebral Maturation and Dental Age in Adolescents: A Cross-Sectional Study.

Background: Considering the high prevalence of vitamin D deficiency and its effect on growth and development, the assessment of the dental age and skeletal age with regard to vitamin D deficiency status could influence the treatment planning of growth modification treatment. This study aimed to assess the relationship between vitamin D deficiency, cervical vertebral maturation (CVM) as an indicator of skeletal age, and dental age in adolescent patients. Methods: In this cross-sectional study, the chronological age of 52 orthodontic patients aged between 10 and 14 years was recorded, and their serum level of vitamin D was determined using a radioimmunoassay test. The patients were then divided into three groups based on their serum vitamin D level: severe deficiency, moderate deficiency, and the control group with normal vitamin D. The panoramic radiographs of patients were assessed to determine their dental age using Demirjian's method. CVM was determined on lateral cephalograms using Baccetti's classification to specify the skeletal age. Data were analyzed using a t-test, linear regression, ordinal logistic regression, and Pearson's correlation coefficient (at P < 0.05, confidence interval = 95%). Results: Skeletal age showed a significant difference between the group with severe vitamin D deficiency and the control group (P=0.01); however, such difference was not observed between the group with moderate vitamin D deficiency and the control group (P=0.12). Dental age was not significantly different between the groups with vitamin D deficiency and the control group (P=0.26 for severe, and P=0.39 for moderate deficiency). Conclusions: A less advanced skeletal maturation was observed in adolescents with severe vitamin D deficiency; however, dental development was not affected by this deficiency. Vitamin D status is better to be considered in decision-making for the initiation of growth modification orthodontic treatments.

Does the size of an object containing dental implant affect the expression of artifacts in cone beam computed tomography imaging?

BACKGROUND: Artifacts fault image quality but handling several factors can affect it. This study was conducted to investigate the effect of object size on artifacts in cone-beam computed tomography systems. METHODS: Five phantoms, each containing a titanium implant in a sheep bone block, were fabricated of various sizes ranging from XS to XL: The M phantom was the same size as the device's field of view (FOV). The L and XL phantoms were 20 and 40% larger than the FOV while the S and XS phantoms were 20 and 40% smaller than FOV, respectively. Ballistic gelatin was used to fill the phantoms. Phantoms were scanned by NewTom VGI and HDXWill Q-FACE. The mean and standard deviation (SD) of gray values in each 120 ROI was obtained by OnDemand software. The contrast to noise ratio (CNR) was also calculated. RESULTS: The gray value in S and M phantoms were more homogenous. The lowest SD value (10.20) was found in S phantom. The highest value for SD (125.16) was observed in XL phantom. The lowest (4.47) and highest (9.92) CNR were obtained in XL and S phantoms, respectively. HDXWill Q-FACE recorded a higher SD and a lower CNR than NewTom VGI (P < 0.05). CONCLUSION: Object dimensions of the FOV size or up to 20% smaller provided better image quality. Since the dimensions of soft tissue in most patients are larger than the selective FOV, it is recommended that in CBCT artifacts studies, an object with dimensions closer to the patient's dimensions be used to better relate the results with the clinical condition, because the sample dimensions affect the amount of artifacts.

ASSESSMENT OF OCCUPATIONAL RADIATION DOSE FROM CAMERA MODEL INTRAORAL HANDHELD X-RAY DEVICE WITHOUT STRAY RADIATION PROTECTION SHIELD.

The aim of this study was to assess the occupational exposure from portable X-ray device without stray radiation protection shield measured using thermoluminescent dosemeters (TLDs). A total of 108 intraoral periapical radiographies of six sextants were performed. The TLDs were located on right index finger and left palm, between the pupils of the eyes at the edges of the Nasion point, Manubrium of Sternum bone and genital area. The detected mean doses per procedure were 70, 99, 60, 51, 51 and 58 µSv in the right finger, left palm, level of the Nasion point, under left clavicle, above the sternum manubrium and at the gonad area, respectively. Maximum number of radiographic images that the operator is allowed to perform depends on eye exposure and in accordance with International Commission on Radiological Protection is 0.16 (0.12-0.23) per hour or 1.28 (0.96-1.84) per day.

Prevalence of pulp stones in an Iranian subpopulation: an assessment using cone beam computed tomography.

Undetected pulp stones can complicate root canal treatment. Knowledge about the prevalence of this anomaly in specific populations can improve endodontic treatment outcomes. The objective of this study was to use cone beam computed tomography (CBCT) to assess the prevalence of pulp stones in an Iranian subpopulation. In this descriptive, analytical, cross-sectional study, the CBCT scans of 150 (75 female and 75 male) patients aged 15 to 70 years were retrieved from the 2017 to 2018 archives of an Iranian university. A total of 4200 teeth were evaluated for the presence of pulp stones by a senior dental student under the supervision of an experienced oral and maxillofacial radiologist. The panoramic radiographic views were evaluated first, and then each tooth was evaluated on sagittal, coronal, axial, cross-sectional, and multiplanar views with 0.5-mm slice thickness. Data regarding the presence of pulp stones as well as the effects of age, sex, tooth type, and jaw on the presence of pulp stones were analyzed using independent t and chi-square tests. Of 4200 teeth, 571 had pulp stones, yielding prevalence rates of 13.6% in the studied teeth and 76.0% in the study population. The prevalence of pulp stones was higher in female patients, the mandible, anterior teeth, and the mandibular left quadrant. The mandibular left central incisor (tooth 24) had the highest (38.7%) and the maxillary left second premolar (tooth 13) had the lowest (1.3%) prevalence of pulp stones. The high prevalence of pulp stones in this study population suggests that dentists should consider the possible presence of pulp stones when planning endodontic treatment for Iranian patients.

Lingual Foramen of the Mandible on Cone-Beam Computed Tomography Scans: A Study of Anatomical Variations in an Iranian Population.

Objectives: Lingual foramen (LF) is an important landmark of the mandible, which should be considered in presurgical assessment. The purpose of this study was to assess the anatomical variations of the LF using cone-beam computed tomography (CBCT). Materials and Methods: The study was conducted on 200 CBCT scans of Iranian adults. The lingual foramina (LFs) were classified into two groups by their location in the mandible namely the medial LFs (MLFs) and the lateral LFs (LLFs). The frequency of both the MLFs and the LLFs and their distance from the inferior border of the mandible were evaluated. Additionally, the diameter of the MLFs and the location of the LLFs were assessed. Data were analyzed separately for males and females. Results: All 200 participants had at least one LF. Totally, 257 LFs were detected on 200 CBCT scans, including 223 MLFs (86.6%) and 34 LLFs (13.3%). The LLF was detected in 23 patients (11.5%). The prevalence of the LLF was higher in males and in the second premolar region. The diameter of the MLFs was less than 1mm in 81% of the cases, and males had a larger MLF. Conclusion: There was a significant variability in the anatomy and location of the mandibular LF in Iranian adults. CBCT is recommended for preoperative imaging to determine the exact location and size of the LFs in the mandible to prevent possible surgical complications.

Prevalence of Nasal Septum Deviation Using Cone-Beam Computed Tomography: A Cross-Sectional Study.

BACKGROUND AND AIM: Nasal septum deviation (NSD) increases the chance of nasal obstruction, sinusitis, and upper airway and middle ear infections and can affect vocal cord activity, beauty, and breathing. The present study investigated the prevalence of NSD and its relation to gender, age, and history of trauma using cone-beam computed tomography (CBCT). SUBJECTS AND METHODS: This cross-sectional study was performed on the data from CBCT examinations of 386 patients referred to two oral and maxillofacial radiology centers in Tehran, Iran, from January 2016 to January 2017. The presence of NSD and its type according to the Mladina's classification were evaluated. The effect of age, gender, and history of trauma on the prevalence of NSD was considered using a logistic regression. RESULTS: 86.6% (confidence interval = 0.81, 0.91) of the patients showed NSD. The prevalence was 19.4% type 1, 6.2% type 2, 20.7% type 3, 5.4% type 4, 4.4% type 5, 0.3% type 6, and 30.3% with type 7. The logistic regression indicated that the chance of deviation of nasal septum increased with age and every 10-year increase in age increased the odds of septal deviation by 0.32 (P < 0.001 and odds ratio = 1.032). Gender (P = 0.094) and history of trauma (P = 0.79) had no effects on the chance of deviation of nasal septum. CONCLUSION: This study showed that the frequency of NSD was 86.6%, with type 7 being the most common type, followed by type 3 and 1. NSD showed no association with trauma and gender, and the increase in age increases the chance of NSD.

Morphological patterns of lip prints in an Iranian population.

BACKGROUND: Lip prints are verified to be unique to an individual and stable over time; hence they have potential for human identification purposes. The aim of this study was to assess the individuality and variability of lip prints in an Iranian population for the first time. We also sought to assess the possibility of sex determination via lip printing. MATERIAL AND METHODS: Lip prints of 96 individuals including 22 males and 74 females were recorded on a plain white paper using a dark-colored lipstick and 50 mm of Scotch tape. Each lip print was divided into six sextants and studied independently by two observers using a magnifying lens to examine the lip grooves. The Suzuki and Tsuchihashi's classification was used to define the lip patterns and the data were statistically analyzed. RESULTS: In the present study, no identically similar lip prints were observed. Type V was the most predominant pattern recorded in the study sample (33.16%), followed by type I (24.13%), type II (18.75%), type IV (11.63%), type I' (9.72%) and type III (2.60%). In addition, no statistically significant difference was observed in the lip print patterns of males and females. CONCLUSIONS: It can be concluded that lip prints are unique and their analysis may enable human identification. Key words:Forensic anthropology, forensic dentistry, forensic medicine, iran, lip.

Effects of Different Viewing Conditions on Radiographic Interpretation.

OBJECTIVES: Optimum viewing conditions facilitate identification of radiographic details and decrease the need for retakes, patients' costs and radiation dose. This study sought to evaluate the effects of different viewing conditions on radiographic interpretation. MATERIALS AND METHODS: This diagnostic study was performed by evaluating radiograph of a 7mm-thick aluminum block, in which 10 holes with 2mm diameters were randomly drilled with depths ranging from 0.05 mm to 0.50mm. The radiograph was viewed by four oral radiologists independently under four viewing conditions, including a white light viewing light box in a lit room, yellow light viewing light box in a lit room, white light viewing light box in a dark room and yellow light viewing light box in a dark room. Number of circular shadows observed on the film was recorded. The data were analyzed by two-way ANOVA. RESULTS: The mean number of detected circular shadows was 6.75, 7.5, 7.25 and 7.75 in white light viewing light box in a lit room, white light viewing light box in a dark room, yellow light viewing light box in a lit room and yellow light viewing light box in a dark room, respectively. Although the surrounding illumination had statistically significant effect on the radiographic details (P≤0.03), the light color of the viewing light box had no significant effect on visibility of the radiographic details. CONCLUSION: White and yellow light of the viewing light box had no significant effect on visibility of the radiographic details but more information was obtained in a dark room.

Correlation between symphyseal morphology and mandibular growth.

BACKGROUND: This study sought to assess symphyseal morphology in adolescents with different mandibular growth patterns (MGPs) in order to see if a relation exists. MATERIALS AND METHODS: In this study the symphyseal parameters (height, depth, and ratio) of normal subjects were compared with four groups with malocclusion (cl III vertical, cl II vertical, cl III horizontal, and cl II horizontal). These groups (15 samples each) were matched (for sex and cervical maturation stage [CVMS]) based on their cephalograms and patient charts. Growth patterns were differentiated by seven vertical parameters and the Wylie analysis. After confirmation of normality of the groups and similarity of their variances the two-way analysis of variance (ANOVA) was used for analysis of data assessed by adjusted chi-square (P < 0.001). The comparison of cases with the normal group was performed by the Dunnett method. Intraclass Correlation Coefficient (ICC) was used for evaluation of intraobserver reliability. RESULTS: We found the symphyseal ratio to have a significant correlation with the MGP (P < 0.001). The symphyseal ratio (Height/Depth) was small in a mandible with vertical growth pattern Cl II or Cl III. Conversely, a horizontal growth pattern of a Cl II or Cl III mandible was associated with a larger ratio of the symphysis in comparison with the normal group. The symphyseal ratio was also found to be greater in females. CONCLUSION: The symphyseal ratio was found to be strongly associated with the MGP.

Relationship between carotid artery calcification detected in dental panoramic images and hypertension and myocardial infarction.

BACKGROUND: Carotid artery calcification may be related to cerebrovascular accident, which may result in death or physical and mental disabilities in survivors. OBJECTIVES: Our purpose is to study the association of carotid artery calcification (CAC) on dental panoramic radiographs and two risk factors of cerebrovascular accident (CVA) including hypertension and myocardial infarction (MI). PATIENTS AND METHODS: Panoramic images of 200 patients that were all women above 50 years of age (a population suffering from vascular diseases) were investigated. All panoramic images were provided under similar conditions in terms of the type of panoramic radiograph equipment, type of applied films and the automatic film processor. Then, the patients answered questions about MI history and taking antihypertensive drugs. We also measured the blood pressure of patients in two separate surveys. Data analysis was performed by SPSS statistical program. We used Exact Fisher test and Chi-Square test at a significant level of less than 0.05 to study the effect of these variables on the occurrence of carotid artery calcification. RESULTS: Among 200 studied samples, 22 of the patients (11%) had carotid artery calcification on the dental panoramic radiograph. In total, 52 patients (26%) had hypertension and four people (2%) had a history of MI. Eleven individuals among patients suffering from hypertension (21.2%) and three individuals among patients with a history of MI (75%) demonstrated CAC on dental panoramic images . CONCLUSIONS: The relationship between CAC found on dental panoramic radiographs and two CVA risk factors--hypertension and MI-- was significant. Therefore, it seems that detection of CAC on panoramic images of dental patients must be considered by dentists.

Radiologic assessment and frequency of idiopathic osteosclerosis of jawbones: an interpopulation comparison.

BACKGROUND: Idiopathic osteosclerosis is a localized growth of compact bone with an unknown cause. This asymptomatic lesion is an insignificant finding and as such requires no treatment. It should be distinguished from other types of osteosclerosis created by inflammatory processes and systemic diseases. PURPOSE: To determine the prevalence and distribution of idiopathic osteosclerosis in the jawbones in Iran and to compare this prevalence and distribution with other populations. MATERIAL AND METHODS: This cross-sectional descriptive study was performed in the Dental School of Shahid Beheshti University of Medical Sciences, Tehran, between 2010 and 2011. Data were collected from the files of patients who underwent panoramic radiography for dental treatment. Location, shape, and relation between idiopathic osteosclerosis and the tooth as well as the resorption of the tooth involved were evaluated. Lesion distribution regarding age, gender, localization, shape, dental relationship, and root resorption was assessed using the chi-squared test. RESULTS: In total, 787 panoramic radiographs of 456 women and 331 men were assessed. Idiopathic osteosclerosis was detected in 75 (9.5%) patients. The prevalence of idiopathic osteosclerosis was significantly higher in the women (11.8% vs. 6.3%; P < 0.01). The mean age of the patients with idiopathic osteosclerosis was 31.9 ± 17.9 years and 30.8 ± 13.3 years in the patients without idiopathic osteosclerosis. The distribution of idiopathic osteosclerosis in the mandible (97.3%), mostly in the premolar region, was significantly higher than that in the maxilla (2.7%). CONCLUSION: Our results showed high frequencies of idiopathic osteosclerosis in Iran in comparison to some other countries.

Predicting mandibular growth increment on the basis of cervical vertebral dimensions in Iranian girls.

BACKGROUND: The purpose of this longitudinal study was to establish an equation to predict incremental mandibular length on the basis of the analysis of the cervical vertebrae on a single cephalometric radiograph and to compare the predictive accuracy with the method by Mito et al. METHODS: Data consist of a group of 33 Iranian girls, 9 to 11 years old with two lateral cephalometric radiographs taken at a 24-month interval. For each individual, on the lateral cephalometric radiographs, points and lines for the description of the morphologic characteristics of the third and fourth cervical vertebral bodies were traced and measured. The real mandibular length increment (MLI) in this period was determined by the difference between the second (24 months) and first (baseline) radiographs: MLI=Ar-Pog (second)-Ar-Pog (first). An equation was determined to calculate mandibular length increments on the basis of the measurements in the third and fourth cervical vertebral bodies. The predictive accuracy was assessed using multiple regression analysis. RESULTS: The adjusted R2 for this equation was 54.9% which is a reliable value for evaluating prediction accuracy .The average error between the predicted increment and the actual increment was 0.149 mm for our method and 5.87 mm for the method by Mito et al. DISCUSSION: There are two items that contributed to easier and better prediction accuracy in our equation: (1) higher R2 and (2) fewer independent variables. In our subjects, the prediction accuracy was lower when using Mito et al.'s method, which could be due to genetic and environmental factors and selected age range. CONCLUSION: These results indicate that cervical vertebral measurements, obtained in lateral cephalograms, are able to predict properly the mandibular growth potential.

Conventional versus digital radiography in detecting root canal type in maxillary premolars: an in vitro study.

OBJECTIVE: Successful endodontic therapy depends on adequate mechanical and chemical debridement of the canal which requires knowledge of the canal morphology. Conventional radiography has been used to evaluate the canal type; however, direct digital radiography has recently been practiced for this purpose due to the shortcomings of conventional radiography. The aim of the present study was to compare the accuracy of digital and conventional radiography taken at 0° and 30° angles in the diagnosis of the canal type of extracted maxillary premolars. MATERIALS AND METHODS: This diagnostic study was performed on 90 extracted maxillary premolars. Conventional and digital radiographies were taken of all teeth at 0° and 30° horizontal angles. The images were assessed by an oral and maxillofacial radiologist. The clearing technique was used as the gold standard. The canal type was determined using Weine classification. The agreement between each one of the 4 radiographic modalities and gold standard was determined by kappa statistics. RESULTS: The kappa values for the agreement of parallel conventional, 30° conventional, parallel digital and 30° digital modalities with the clearing technique were 0.059, 0.215, 0.043 and 0.391, respectively. Parallel modalities were unable to determine the tooth canal type. Radiographic images taken at 30° significantly determined the canal type, although only a poor level of agreement was noted between the two modalities and the clearing technique. CONCLUSION: All modalities had limited value to determine the root canal type in maxillary premolars. However, direct digital imaging taken at 30° angle showed the highest accuracy for canal type assessment.

Oro-facial manifestations of 100 leprosy patients

Objectives: To verify the frequency of oral and facial involvement in diagnosed leprosy patients. Study design: This study was performed on 100 leprosy patients (62 male, 38 female, mean ages 51.86±6.1). After explaining the study design, we studied descriptive information including: patient’s sex, age, job, place of birth, familial history of leprosy, types of disease (lepromatous, borderline and tuberculoid leprosy), ocular and oral lesions, facial involvement and neuropathy. The statistical signification was measured by chi-square test. Results: A total of 46 (23 lepromatous, 15 borderline, and 8 tuberculoid leproy) out of 100 patients with leprosy had oral lesions. Statistical analysis did not show any significant difference in frequency of oral lesions between different types of disease. Facial lesions were presented in 57 (39 lepromatous, 10 borderline, and 8 tuberculoid leprosy) patients. There was a statistical significant difference in frequency of facial manifestations between different types of leprosy. It has to be mentioned that, atrophy of nasal spine, facial nerve involvement, ocular lesions and facial deformity were seen in 15%, 17%, 22% and 44% of leprosy patients, respectively. Conclusion: Examination of leprosy patients should be extended to the oral mucosa because oral mucosa may be a secondary source of M.Leprae transmission and infection (AU)

Oro-facial manifestations of 100 leprosy patients.

OBJECTIVES: To verify the frequency of oral and facial involvement in diagnosed leprosy patients. STUDY DESIGN: This study was performed on 100 leprosy patients (62 male, 38 female, mean ages 51.86±6.1). After explaining the study design, we studied descriptive information including: patient' s sex, age, job, place of birth, familial history of leprosy, types of disease (lepromatous, borderline and tuberculoid leprosy), ocular and oral lesions, facial involvement and neuropathy. The statistical signification was measured by chi-square test. RESULTS: A total of 46 (23 lepromatous, 15 borderline, and 8 tuberculoid leprosy) out of 100 patients with leprosy had oral lesions. Statistical analysis did not show any significant difference in frequency of oral lesions between different types of disease. Facial lesions were presented in 57 (39 lepromatous, 10 borderline, and 8 tuberculoid leprosy) patients. There was a statistical significant difference in frequency of facial manifestations between different types of leprosy. It has to be mentioned that, atrophy of nasal spine, facial nerve involvement, ocular lesions and facial deformity were seen in 15%, 17%, 22% and 44% of leprosy patients, respectively. CONCLUSION: Examination of leprosy patients should be extended to the oral mucosa because oral mucosa may be a secondary source of M.Leprae transmission and infection.

Analysis of linear measurement accuracy obtained by cone beam computed tomography (CBCT-NewTom VG).

BACKGROUND: One of the major uses of cone beam computed tomography (CBCT) is presurgical implant planning. Linear measurement is used for the determination of the quantity of alveolar bone (height and width). Linear measurements are used in orthodontic analysis and definition of jaw tumor size. The objective of this study is to evaluate the accuracy of the linear measurement of CBCT (Newtom VG) in the axial and coronal planes, with two different voxel sizes. MATERIALS AND METHODS: In this accuracy diagnostic study, 22 anatomic landmarks in four dry human skulls were marked by gutta-percha. Fifteen linear measurements were obtained using a digital caliper. These were considered to be the gold standard (real measurement). The skulls were scanned by CBCT (Newtom VG) at two settings: (a) Voxel size 0.3 mm (b) voxel size 0.15 mm High Resolution (HR). The radiographic distance measurements were made in the axial and coronal sections by three observers. The radiographic measurements were repeated two weeks later for evaluation of intraobserver reliability. SPSS software version 17 was used for data analysis. The level of significance was considered to be 5% (P ≤ 0.05). RESULTS: The mean differences of real and radiographic measurements were -0.10±0.99 mm in the axial sections, -0.27±1.07 mm in the coronal sections, +0.14±1.44 mm in the axial (HR) sections, and 0.02±1.4 mm in the coronal (HR) sections. The intraclass correlation (ICC) for CBCT measurements in the axial sections was 0.9944, coronal sections 0.9941, axial (HR) sections 0.9935, and coronal (HR) sections 0.9937. The statistical analysis showed high interobserver and intraobserver reliability (P ≤ 0.05). CONCLUSION: CBCT (Newtom VG) is highly accurate and reproducible in linear measurements in the axial and coronal image planes and in different areas of the maxillofacial region. According to the findings of the present study, a CBCT scan with a larger voxel size (0.3 mm in comparison to 0.15 mm) is recommended when the purpose of the CBCT scan is to measure linear distances. This will result in lower patient radiation dose and faster scan time.

Prevalence of calcified carotid artery on panoramic radiographs in postmenopausal women.

BACKGROUND AND AIMS: This study was designed to evaluate the prevalence of calcified carotid artery in 50 year-old and older postmenopausal dental outpatients for early diagnosis of individuals at risk of stroke. MATERIALS AND METHODS: This is a descriptive study of 200 panoramic radiographs. These radiographs included post-menopausal women referring to the Department of Oral Medicine at Shahid Beheshti Faculty of Dentistry during 2006-2007. The x-ray machine, developer and film type were the same for all the radiographs. Statistical analysis included chi-square test and Fisher's exact test. RESULTS: We found 22 calcified carotid arteries. The left and right carotid arteries were involved in 7 and 9 cases, respec-tively. In 6 cases both carotid arteries were calcified. Four individuals had no vascular risk factor excluding age and others had at least one risk factor. We found significant statistical correlation between hypertension, past history of myocardial infarction, and hypercholesterolemia with calcified carotid artery on panoramic radiographs. CONCLUSION: Under the limitations of the present study, prevalence of calcified carotid arteries is 11.0 % in 50 year-old and older postmenopausal dental outpatients.