Showing 5 results for Alizadeh
S Mehralizadeh, S Nemati Anaraki, M Orshesh,
Volume 2, Issue 4 (10-2017)
Abstract
Background and Aim: Considering the consequences of false positive (FP) and false negative (FN) diagnoses as well as the lack of information on the diagnostic ability of photostimulable phosphor plate (PSP) and complementary metal oxide semiconductor (CMOS) sensors in the detection of secondary caries, this study aimed to compare the diagnostic ability of these two sensors in the detection of secondary caries adjacent to amalgam restorations.
Materials and Methods: This diagnostic study was performed on 40 intact permanent premolars. Class II cavities were prepared and restored with amalgam. Periapical radiography was performed by using PSP and CMOS sensors via parallel technique. A 0.5-mm round bur was used to create another cavity under amalgam restorations. To simulate secondary gingival caries at the cementoenamel junction (CEJ), the samples were placed inside 0.1M lactic acid solution and were incubated at 37°C for three weeks. The teeth were placed in gypsum blocks and were radiographed again by CMOS and PSP sensors. The presence of decay was determined by an oral and maxillofacial radiologist, and the results were recorded in datasheets and were statistically analyzed by the ratio test.
Results: The sensitivity and specificity of PSP in caries detection were 52.5% and 77.5%, respectively. The sensitivity and specificity of CMOS in caries detection were 57.5% and 82.5%, respectively. Incorrect diagnoses (FP+FN) were equal to 35% for PSP and 30% for CMOS (P=0.89).
Conclusion: The results indicated that PSP and CMOS sensors have similar abilities in the detection of secondary caries under amalgam restorations, while none of the two sensors has the adequate ability for a precise and thorough diagnosis of secondary caries.
N Nadafpour, Fb Ghaedi, Z Verdipanah, Z Alizadeh Tabari,
Volume 3, Issue 4 (10-2018)
Abstract
Background and Aim: The knowledge and performance of obstetrics and gynecology (OBG) specialists regarding the relationship between maternal periodontal disease and pregnancy complications are unclear, especially in Iran. Considering the key role of this group in evaluating pregnant women at risk, we aimed to determine the knowledge and performance of OBG specialists and residents regarding the effects of periodontal disease on pregnancy outcomes at therapeutic centers of Tehran University of Medical Sciences.
Materials and Methods: Questionnaires containing individual and exclusive questions were provided to OBG specialists and residents. Of the 92 questionnaires, 67 were returned, of which 58 were evaluable. Absolute and relative frequencies and the knowledge and performance scores of each group were determined and compared. Data were analyzed using independent t-test and Chi-square test.
Results: 71% of OBG residents and 77.8% of OBG specialists were familiar with periodontal disease via scientific texts. The mean awareness score of OBG residents and specialists was respectively 69.13±15.35 and 83.7±16.7; the difference was significant. There was no significant correlation between the awareness of gynecologists about the effect of periodontal diseases on pregnancy outcomes with their work experience. The mean performance scores of OBG specialists and residents was 51.13±31.1 and 41.9±28.8, respectively, with no significant difference. There was no significant relationship between the referral behaviors of OBG specialists and their work experience.
Conclusion: The awareness of OBG specialists and residents about the correlation between pregnancy and gingival disease was good, but their performance was moderate. Attendance of OBG specialists and residents to retraining courses will improve their awareness and performance.
E Jalalian, E Hashemi, Sh Naser Mostufi, Ar Banifatemeh, M Shariati, A Pirmoazen, S Alizadeh,
Volume 4, Issue 1 (3-2019)
Abstract
Background and Aim: Maintaining the primary torque of the abutment screw is a common problem related to implant-supported restorations; a failure in this respect often leads to screw loosening. The abutment screw plays a critical role in the long-term stability of restorations. This study aimed to assess the effect of two abutment connection types with and without cyclic loading on removal torque value (RTV).
Materials and Methods: A total of 24 abutments and fixtures were evaluated in this in-vitro experimental study. Two abutments with internal and external connections were tightened to fixtures using a digital torque-meter according to the manufacturer's instructions. Half of the samples were subjected to cyclic loading with a 100-N mechanical load at a 1-Hz frequency (500,000 cycles) applied at 23±1°C with 50±5% humidity. Next, the RTV was measured for each abutment. Two-way analysis of variance (ANOVA) was used to assess the effect of the abutment system and cyclic loading on RTV.
Results: The highest RTV belonged to the internal connection abutment without cyclic loading (22 Newton-centimeter (Ncm)), while the lowest RTV was noted with the external connection abutment subjected to cyclic loading (14 Ncm; P<0.01). There was no statistically significant interaction effect between the two variables (the abutment system and cyclic loading; P=0.839). The RTV in the internal hexagon abutments was significantly higher than that in the external hexagon abutment system (P<0.001). Cyclic loading significantly reduced the RTVs in both abutments (P<0.001).
Conclusion: According to the results, internal connection abutments experience less screw loosening.
S Mehralizadeh, Ar Talaipour, P Olyaee, M Amiri Siavoshani,
Volume 5, Issue 1 (2-2020)
Abstract
Background and Aim: Bone density is of great assistance in the selection of the proper implant site. The present study aimed to assess the correlation between tissue densities in computed tomography (CT) and three different cone-beam computed tomography (CBCT) units.
Materials and Methods: In this descriptive study, a radiographic phantom consisting of a transparent polymethyl methacrylate (PMMA) cylinder with a 50-mm height and a 50-mm diameter was used, which comprised eight materials, including air, fat, water, PMMA, muscle, cortical bone, cancellous bone, and aluminum. Each material was of 5 mm height and 5 mm in diameter. A 20-mm-thick hollow plexiglass cylinder was used to simulate the soft tissue. The phantom was scanned four times using 16-Slice Lightspeed CT, NewTom VGi, CRANEX 3D, and Rotograph Evo 3D CBCT units. The data were primarily reconstructed and transferred to the OnDemand 3D software in the Digital Imaging and Communications in Medicine (DICOM) format. All the assessments were made in the sagittal plane, and the average density of each of the mentioned eight materials was calculated with the proper grayscale value calculation of each system, which utilizes a simulation inherent density calculation for any region of interest (ROI).
Results: The results showed that tissue densities are different in CT and CBCT units. The values estimated by the CRANEX 3D unit approximated that of CT, followed by NewTom VGi and Rotograph Evo 3D CBCT units. Kruskal-Wallis test showed that the differences in the scores are statistically significant (P<0.01),
Conclusion: Considering the results, CBCT cannot accurately calculate tissue density.
S Valizadeh, L Hafezi, A Hasanzdeh Azhiri,
Volume 7, Issue 2 (3-2022)
Abstract
Abstract
Background and Aim: This study aimed to assess the bone
thickness at the interradicular spaces in the anterior mandible on cone-beam computed tomography (CBCT) scans of patients to find appropriate sites for mini-implant and miniscrew placement.
Materials and Methods: This analytical cross-sectional study was conducted on 161 CBCT scans of patients (98 females and 63 males) between 18 to 50 years old presenting to the School of Dentistry of
Islamic Azad University in 2020. Cross-sectional images with 1 mm slice thickness were evaluated to measure the bone thickness at the interradicular areas at 3, 6, 9, 12, 15, and 18 mm distance from the mandibular alveolar crest. The measurements made from the distal surface of right canine to the distal surface of left canine teeth were recorded. The CBCT scans had been taken by Rotograph Evo 3D CBCT scanner, and were analyzed by OnDemand3D software. Data were statistically analyzed by t-test.
Results: Bone thickness at 11 sites in the anterior mandible was significantly higher in males (P<0.05). By an increase in depth in both males and females, the mean thickness of bone increased (P<0.05). The maximum mean bone thickness in males and females was at 18 mm depth between the central incisors.
Conclusion: To find a correct site for mini-implant and miniscrew placement, it should be noted that bone thickness would be greater at deeper areas, and by moving from the premolar site towards the
incisors. |