Prevalence of idiopathic osteosclerosis in an Iranian population.

AIM: Idiopathic osteosclerosis (IO) is a localized radiopacity with no associated pain, bony expansion, symptom, or known etiology. The aim of this study was to assess its frequency and distribution according to its location and patient's age and gender and internal structure using panoramic radiography. SUBJECTS AND METHODS: In this retrospective study, 3975 panoramic radiographs (PRs) were used. Radiopaque regions which had no certain relationship to any known sources of hard tissue production were accepted as IO and characteristics such as shape, location, internal structure, and personal information were investigated. STATISTICAL ANALYSIS USED: The obtained data were evaluated using SPSS software and Chi-square test. RESULTS: IO was found in 113 (2.84%) out of 3975 patients. The most frequent site was the posterior region of mandible. There was no significant difference in the incidence of IO between genders (P = 0.766). CONCLUSION: IO is an asymptomatic radiopaque mass commonly seen in PR, which was found mostly in the first molar region of mandible. Furthermore, its maximum frequency was in the second decade.

A comparative study of accuracy of linear measurements using cone beam and multi-slice computed tomographies for evaluation of mandibular canal location in dry mandibles.

BACKGROUND: Cross- sectional tomograms have been used for optimal pre-operative planning of dental implant placement. The aim of the present study was to assess the accuracy of Cone Beam Computed Tomography (CBCT) measurements of specific distances around the mandibular canal by comparing them to those obtained from Multi-Slice Computed Tomography (MSCT) images. MATERIALS AND METHODS: Ten hemi-mandible specimens were examined using CBCT and MSCT. Before imaging, wires were placed at 7 locations between the anterior margin of the third molar and the anterior margin of the second premolar as reference points. Following distances were measured by two observers on each cross-sectional CBCT and MSCT image: Mandibular Width (W), Length (L), Upper Distance (UD), Lower Distance (LD), Buccal Distance (BD), and Lingual Distance (LID). The obtained data were evaluated using SPSS software, applying paired t-test and intra-class correlation coefficient (ICC). RESULTS: There was a significant difference between the values obtained by MSCT and CBCT measurement for all areas such as H, W, UD, LD, BD, and LID, (P < 0.001), with a difference less than 1 mm. The ICC for all distances by both techniques, measured by a single observer with a one week interval and between 2 observers was 99% and 98%, respectively. Comparing the obtained data of both techniques indicates that the difference between two techniques is 2.17% relative to MSCT. CONCLUSION: The results of this study showed that there is significant difference between measurements obtained by CBCT and MSCT. However, the difference is not clinically significant.

Comparison of Conventional and Standardized Bone Densitometry around Implants in Periapical Radiographs during a Three Months Period.

BACKGROUND: Comparing continuous films taken at different timescales is a way to study the alveolar bone changes around the implant over time. One of the important concerns in quantitative analysis of the alveolar bone changes over the time is to reduce variations in the X-ray imaging geometry and image density. METHODS: Using a modified XCP film holder together with the bite recording material, parallel periapical radiographs were taken from the implants placements of 16 patients in four steps. Densities of radiographs were measured in a conventional way using the video densitometry device. The same films were also scanned; sequential radiographic density of each patient was homogenised and the density was measured. Density changes obtained in both methods were compared. The data were evaluated using ANOVA, paired t-test and Pearson correlation (α = 0.05). RESULTS: IN THE CONVENTIONAL METHOD OF DENSITOMETRY, THE AVERAGE DENSITIES WERE AS FOLLOWS: before operation 1.0044, after one week 0.9600, after one month 0.9469 and after three months 0.9398. Also, in the standard method of densitometry, the average densities were as follows: before operation 111.7013, after one week 113.4225, after one month 119.4075 and after three months 131.1162. Average density in conventional densitometry were not significantly different in various time stages (P = 0.395). But, the standard densitometry method showed a significant difference (P = 0.001). CONCLUSION: The average density obtained at different stages in the standard densitometry showed a gradual increase in the bone density in the entire process. Standardising the patient's consecutive radiographic images is essential for quantitative measurements over the time.

Comparison of accuracy of uncorrected and corrected sagittal tomography in detection of mandibular condyle erosions: an exvivo study.

BACKGROUND: Radiographic examination of TMJ is indicated when there are clinical signs of pathological conditions, mainly bone changes that may influence the diagnosis and treatment planning. The purpose of this study was to evaluate and to compare the validity and diagnostic accuracy of uncorrected and corrected sagittal tomographic images in the detection of simulated mandibular condyle erosions. METHODS: Simulated lesions were created in 10 dry mandibles using a dental round bur. Using uncorrected and corrected sagittal tomography techniques, mandibular condyles were imaged by a Cranex Tome X-ray unit before and after creating the lesions. The uncorrected and corrected tomography images were examined by two independent observers for absence or presence of a lesion. The accuracy for detecting mandibular condyle lesions was expressed as sensitivity, specificity, and validity values. Differences between the two radiographic modalities were tested by Wilcoxon for paired data tests. Inter-observer agreement was determined by Cohen's Kappa. RESULTS: The sensitivity, specificity and validity were 45%, 85% and 30% in uncorrected sagittal tomographic images, respectively, and 70%, 92.5% and 60% in corrected sagittal tomographic images, respectively. There was a significant statistical difference between the accuracy of uncorrected and corrected sagittal tomography in detection of mandibular condyle erosions (P = 0.016). The inter-observer agreement was slight for uncorrected sagittal tomography and moderate for corrected sagittal tomography. CONCLUSION: The accuracy of corrected sagittal tomography is significantly higher than that of uncorrected sagittal tomography. Therefore, corrected sagittal tomography seems to be a better modality in detection of mandibular condyle erosions.