Showing 8 results for Panjnoush
Ar. Talaeipour , M. Panjnoush , N. Anbiaei ,
Volume 17, Issue 1 (7 2004)
Abstract
Statement of Problem: Subtraction is a newly presented radiography technique to detect minor density changes that are not visible by conventional radiography.
Purpose: The aim of this In-vitro study was to evaluate the efficacy of photoshop subtraction software for detecting minor density changes between two dental images.
Materials and Methods: In this research, five dried human mandibles were held in fixed position while thin aluminium sheets were superimposed on each mandible on the 1th and 2nd molar teeth regions.A reference image, without aluminium sheet placement, was obtained from each mandible subsequently series consist of 20 images with aluminium sheets, ranging from 50p. to "5Q0"x were recorded by radiovisiography (RVG) system. Initial images were subtracted from subsequent ones by Photoshop subtraction software. The difference in density between the two images at the 1st and 2nd molar sites was related to the aluminium sheets. The optical density of aluminium sheets was determined by densitometer.
Results: In the present study, 6.6% of the optical density changes of the minimum aluminium thickness as 300u. could be detected by photoshop software software.
Conclusion: The findings of this study showed that the accuracy of photoshop subtraction software was equal to that of the conventional subtraction softwares. Additionally, the accuracy of this software was proved to be suitable for clinical investigations of small localized changes in alveolar bone.
M. Panjnoush , Gh. Shirani , P. Jozghanbari ,
Volume 19, Issue 3 (4 2006)
Abstract
Background and Aim: In recent years, CT scan has become available as an alternative to conventional radiography. To date, the utility of Waters view in detecting midface fractures has been rarely evaluated. The aim of this study was to compare the diagnostic accuracy and reliability of Waters radiography with CT scan in detecting midface fractures.
Materials and Methods: In this tests evaluation study, waters view and CT scan were performed for 42 patients with midface fracture admitted to maxillofacial surgery department of Shariati hospital. All images were observed and interpreted by an oral and maxillofacial radiologist and an oral and maxillofacial surgeon. Sensitivity, specificity and reliability for Waters view in detecting midface fractures were assessed by Cohen’s kappa test.
Results: Sensitivity and specificity for Waters view in detection of midface fratures by the radiologist were 31.79% and 95.35% and by the surgeon were 29.59% and 93.75% respectively. The highest reliability in CT scan and Waters view (in nasal fractures) by the radiologist was 66.67% and was 58.33% by the surgeon in buttress of zygoma. The highest agreement rate between the radiologist and the surgeon for CT scan was in zygomatic arch (78.95%) and for Waters view was in nasal fracture (62.5%).
Conclusion: Based on the results of this study, the specificity of Waters view is sufficient to diagnose fractures of lateral orbital wall, infraorbital rim, orbital floor, zygomatic arch, frontozygomatic suture, lateral wall of maxillary sinus and Lefort II fracture. The specificity is not sufficient to diagnose fractures of medial orbital wall and anterior, posterior and medial wall of maxillary sinus. Detection of these midface fractures needs other conventional radiographies or CT scan.
Ar. Talaeipour , M. Panjnoush , R. Zargarpour ,
Volume 20, Issue 3 (4 2007)
Abstract
Background and Aim: Accurate measurement of bone height and width is essential prior to dental implant placement. The method of surgery as well as, the type and size of implants are determined according to dimensions of the residual bone. The purpose of this study was to evaluate the accuracy of linear tomography in localization of the floor of nasal fossa and maxillary sinus, and to determine the width of maxillary bone at the designated site for implant placement.
Materials and Methods: In this test evaluation study, the vertical distances between the alveolar crest and the floor of nasal fossa and the floor of maxillary sinus was measured by the tomographic slices in 12 sites of three dry human skulls. In addition, the width of maxillary bone was measured at the same slices. The skulls were then sectioned through the marked places. Then the radiographic values were compared with the real values of bone sections.
Results: After correction of tomographic values by the magnification factor of the unit, the mean absolute measurement error for vertical values at nasal fossa and maxillary sinus area in tomographic slices were 0.28 mm (SD= 0.24) and 1.1 mm (SD= 0.68) respectively. The mean absolute measurement error for maxillary width at the nasal fossa and maxillary sinus area were 0.65 mm (SD= 0.50) and 0.55 mm (SD= 0.45) respectively. 100 % of vertical values at nasal fossa area and 50 % of vertical values at maxillary sinus area were within ± 1 mm error limit. In addition, 50 % of width measurements at nasal fossa area and 83.3 % at maxillary sinus area were within ± 1 mm error limit.
Conclusion: The linear tomography is more accurate in height estimation at nasal fossa area and in width estimation at maxillary sinus area. The accuracy of linear tomography in height and width estimation is within acceptable limits at both nasal fossa and maxillary sinus area.
M. Panjnoush, Z. Ghoncheh, A. Sarrafzadeh,
Volume 21, Issue 3 (8 2008)
Abstract
Background and Aim: Digital subtraction Radiography (DSR) is a method of accurate assessing condylar head changes. several studies have been carried out in applying DSR in dentistry, however there is a few number of studies in efficacy of DSR method in assesment of condylar head changes, The aim of this study was to compare panoramic radiography and DSR detecting simulated lesions of the mandibular condyl.
Materials and Methods: this was a process reaserch study, in which two dry human skulls with no obvious temporomandibular joint pathology were used. Osteophytic lesions were simulated using three sizes of bone chips that were placed on the medial portion of anterior and superolateral aspects of the condyle. Osteolytic lesions were simulated making 1 and 2 mm holes using round burr in the central portion of anterior aspect and Lateral pole of the condyle. Panoramic radiographs were prepared with and without the lesions in place. These paired radiographs were digitized and digital- subtraction images of the original panoramic images were obtained. Eight observers evaluated 155 images of each modality for the presence or absence and the type of simulated lesions of the mandibular condyle. Sensitivity, specificity, reliability and measure of agreement were analyzed using kappa test and crossed tables and qualitative variables were assess by chi-square and fisher's Exact test.
Results: Specificity of panoramic and DSR methods were 15.4% and 66.7% respectively. Sensitivity of panoramic and DSR methods were 61.1% and 80.6% for osteophytic lesions and 37.5% and 83.3% for Osteolytic lesions. The percentage of correct decisions made in DSR method was significantly more than conventional panoramic method (82.6% vs 41.9%) (p<0.0001).
Conclusion: Based on the results of this study digital subtraction technique was significantly more accurate than the panoramic radiographs in detection of simulated lesions of the mandibular condyle.
M. Panjnoush, A. Shokri, M. Hosseini Pouya, M. Deevband,
Volume 22, Issue 3 (1 2009)
Abstract
Background and Aim: The objective of this study was to measure and compare the tissue absorbed dose in thyroid gland, salivary glands, eye and skin in maxillofacial imaging with panoramic, conventional linear tomography, cone beam computed tomography (CBCT) and computed tomography (CT).
Materials and Methods: Thermoluminescent dosimeters (TLD) were implanted in 14 sites of RANDO phantom to measure average tissue absorbed dose in thyroid gland, parotid glands, submandibular glands, sublingual gland, lenses and buccal skin. The Promax (PLANMECA, Helsinki, Finland) unit was selected for Panoramic, conventional linear tomography and cone beam computed tomography examinations and spiral Hispeed/Fxi (General Electric,USA) was selected for CT examination. The average tissue absorbed doses were used for the calculation of the equivalent and effective doses in each organ.
Results: The average absorbed dose for Panoramic ranged from 0.038 mGY (Buccal skin) to 0.308 mGY (submandibular gland), linear tomography ranged from 0.048 mGY (Lens) to 0.510 mGY (submandibular gland),CBCT ranged from 0.322 mGY (thyroid glad) to 1.144 mGY (Parotid gland) and in CT ranged from 2.495 mGY (sublingual gland) to 3.424 mGY (submandibular gland). Total effective dose in CBCT is 5 times greater than Panoramic and 4 times greater than linear tomography, and in CT, 30 and 22 times greater than Panoramic and linear tomography, respectively. Total effective dose in CT is 6 times greater than CBCT.
Conclusion: For obtaining 3-dimensional (3D) information in maxillofacial region, CBCT delivers the lower dose than CT, and should be preferred over a medical CT imaging. Furthermore, during maxillofacial imaging, salivary glands receive the highest dose of radiation.
M. Panjnoush , M. Mirzaey , M. Tari ,
Volume 23, Issue 2 (23 2010)
Abstract
Background and Aims: Radiographic examination prior to implant placement is often complemented with tomography for location of vital anatomic structures and evaluation of bone volume. The aim of this study was to evaluate the accuracy of Photostimulable Phosphor Plate system with that of conventional film-screen in mandibular pre-implant linear tomography
Materials and Methods: In this test evaluation study, tomograms of 2 dry human mandibles were taken using the both film-screen and Photostimulable Phosphor Plate. 10 sites were selected in each mandible and marked with gutta-percha. Distance of superior border to the mandibular canal and the total height and width of mandible were measured on the tomograms and also on the mandibles after sectioning. The radiographic values were compared with real ones.
Results: After correction of tomographic values by the magnification factor of the unit, the mean of absolute differences with reality in linear tomography using film-screen and Photostimulable Phosphor Plate for height of mandible were 0.59mm (SD=0.54) and 0.65mm (SD=0.72), respectively. The mean of absolute differences with reality in linear tomography using film-screen and Photostimulable Phosphor Plate for width of mandible were 0.34mm (SD=0.33) and 0.31mm (SD=0.33), respectively. In localization of the mandibular canal, the mean of absolute differences with reality were 0.54mm (SD=0.30 ) and 0.52mm (SD=0.56) for linear tomography using film-screen and Photostimulable Phosphor Plate, respectively. In linear tomography using film-screen, 100% of measurements for localization of the canal, 80% of height and 95% of width were with in ± 1mm error limits. In linear tomography using Photostimulable Phosphor Plate, 75% of measurements for localization of the canal, 75% of height and 95% of width were within ± 1mm error limits. There was no significant difference between linear tomography using film-screen and Photostimulable Phosphor Plate in localizing the mandibular canal and height and width estimation (P>0.05).
Conclusion: The accuracy of linear tomography using film-screen and Photostimulable Phosphor Plate in height and width estimation and localization of the canal is within acceptable limits.
Mehrdad Panjnoush, Zahra Ghoncheh, Hoda Banihashemi, Farnosh Taghavi,
Volume 24, Issue 4 (28 2012)
Abstract
Background and Aims: Disc displacement is the most common temporomandibular joint disorder and magnetic resonance imaging (MRI) is the gold standard in its diagnosis. This disorder can lead to changes in signal intensity of magnetic resonance (MR). The purpose of this study was evaluation of correlation between relative signal intensity of MR images of retrodiscal tissue, superior and inferior head of lateral ptrygoid muscle with type of anterior disk displacement and condylar head flattening in patients with temporomandibular disorder (TMD).
Materials and Methods: In this retrospective study, 31 MR images of patients who had anterior disc displacement were evaluated. After relative signal intensity measurement for retrodiscal tissue, superior and inferior head of lateral ptrygoid muscle, the correlation between relative signal intensity and type of anterior disc displacement was evaluated with repeated measure ANOVA test. In each of these 3 areas, t-test was used to compare the groups with and without condylar head flattening.
Results: The correlation between relative signal intensity of MR images and type of anterior disc displacement in retrodiscal tissue, superior and inferior head of lateral ptrygoid muscle was not significant. There was also no statistically significant correlation between relative signal intensity of MR images and flattening of condylar head in retrodiscal tissue, superior and inferior head of lateral ptrygoid muscle (P>0.05).
Conclusion: According to findings of this study, relative signal intensity of MR images in retrodiscal tissue, superior and inferior head of ptrygoid muscle is not a good predictor for type of anterior disc displacement and flattening of condylar head. It seems that this cannot be used as a diagnostic marker for TMD progression.
Hosnie Yusefi Fakhr, Yadollah Soleimani Shayesteh, Afshin Khorsand, Mehrdad Panjnoush, Mohammad Javad Kharazi Fard, Mohadeseh Heidari,
Volume 35, Issue 0 (5-2022)
Abstract
Background and Aims: According to the importance of primary stability on dental implant success and osseointegration, we intend to check and compare the stability and crestal bone loss rate between osteotomy technique and conventional implant insertion techniques.
Materials and Methods: In this study, 26 implants in anterior segment of maxilla in 13 patients were evaluated. The implants were TBR system (Toulouse, France) with 3.5 diameter and 10.5-12 mm length. The implant stability level was recorded immediately after surgery and 3 months later with Ostell mentor. The periapical radiography was taken immediately after surgery, 3 and 6 months to assess crestal bone resorption. Paired t-test and Wilcoxon signed Rank test used for data analysis.
Results: There were no statistically differences between the two treatments techniques in terms of stability (P>0.05). The mean crestal resorption was higher for the osteotomy technique 3 months after implant insertion (P<0.001) but there were no significant differences after 6 months (P=0.678).
Conclusion: Within the limitations of the current study, it can be concluded that the osteotomy it can be considered as a treatment technique in insufficient bone width.
