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Shahmirzadi, Solaleh,Sharaf, Rana A.,Saadat, Sarang,Moore, William S.,Geha, Hassem,Tamimi, Dania,Kocasarac, Husniye Demirturk Korean Academy of Oral and Maxillofacial Radiology 2021 Imaging Science in Dentistry Vol.51 No.1
Purpose: The aim of this study was to assess artifacts generated in cone-beam computed tomography (CBCT) of 3 types of dental implants using 3 metal artifact reduction (MAR) algorithm conditions (pre-acquisition MAR, post-acquisition MAR, and no MAR), and 2 peak kilovoltage (kVp) settings. Materials and Methods: Titanium-zirconium, titanium, and zirconium alloy implants were placed in a dry mandible. CBCT images were acquired using 84 and 90 kVp and at normal resolution for all 3 MAR conditions. The images were analyzed using ImageJ software (National Institutes of Health, Bethesda, MD) to calculate the intensity of artifacts for each combination of material and settings. A 3-factor analysis of variance model with up to 3-way interactions was used to determine whether there was a statistically significant difference in the mean intensity of artifacts associated with each factor. Results: The analysis of all 3 MAR conditions showed that using no MAR resulted in substantially more severe artifacts than either of the 2 MAR algorithms for the 3 implant materials; however, there were no significant differences between pre- and post-acquisition MAR. The 90 kVp setting generated less intense artifacts on average than the 84 kVp setting. The titanium-zirconium alloy generated significantly less intense artifacts than zirconium. Titanium generated artifacts at an intermediate level relative to the other 2 implant materials, but was not statistically significantly different from either. Conclusion: This in vitro study suggests that artifacts can be minimized by using a titanium-zirconium alloy at the 90 kVp setting, with either MAR setting.
Shahmirzadi Solaleh,Maghsoodi-Zahedi Taraneh,Saadat Sarang,Demirturk Kocasarac Husniye,Rezvan Mehrnoosh,Katkar Rujuta A.,Nair Madhu K. 대한영상치의학회 2023 Imaging Science in Dentistry Vol.53 No.1
Purpose: The aim of this study was to evaluate 3-dimensional cone-beam computed tomography (CBCT) images of alveolar bone changes in patients who underwent minimally invasive periodontal surgery-namely, the pinhole surgical technique (PST). Materials and Methods: Alveolar bone height was measured and compared on CBCT images of 254 teeth from 23 consecutive patients with Miller class I, II, or III recession who had undergone PST. No patient with active periodontal disease was selected for surgery. Two different methods were used to assess the alveolar bone changes postoperatively. In both methods, the distance between the apex of the tooth and the mid-buccal alveolar crestal bone on pre- and post-surgical CBCT studies was measured. Results: An average alveolar bone gain >0.5 mm following PST was identified using CBCT (P = 0.05). None of the demographic variables, including sex, age, and time since surgery, had any significant effect on bone gain during follow-up, which ranged from 8 months to 3 years. Conclusion: PST appears to be a promising treatment modality for recession that results in stable clinical outcomes and may lead to some level of resolution on the bone level. More long-term studies must be done to evaluate the impact of this novel technique on bone remodeling and to assess sustained bone levels within a larger study population.
Seyed Saeid Hosseini,Mohammad Amin Alaei Shahmirzadi,Nicolas Raymond Tan 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.12
Natural and modified zeolite and bentonite are investigated and characterized for extraction of magnesium from aqueous solutions. Magnesium removals as high as 85.21% and 81.73% were achieved by calcined bentonite and microwave radiated zeolite, respectively. The effects of various operational parameters were studied and optimized using selected isotherms. Maximum Mg (II) adsorption capacities of 26.24 and 35.67mg·g−1 were obtained on pristine and calcined bentonites, respectively. Thermodynamic studies suggest that magnesium adsorption on natural bentonite is spontaneous and endothermic (9.13 kj·mol−1). Also, desorption study of natural bentonite demonstrates that HNO3 is more effective by offering 89.11% desorption than other desorptive counterparts.
Park, Sang Kil,Dodaran, Asgar Ahadpour,Han, Chong Soo,Shahmirzadi, Mohammad Ebrahim Meshkati The Society of Naval Architects of Korea 2014 International Journal of Naval Architecture and Oc Vol.6 No.4
Rubble mound breakwaters protect the coastal line against severe erosion caused by wave action. This study examined the performance of different sizes and properties (i.e. height of vertical wall and tetrapod size) of rubble mound breakwaters on reducing the overtopping discharge. The physical model used in this study was derived based on an actual rubble mound in Busan Yacht Harbor. This research attempts to fill the gap in practical knowledge on the combined effect of the armor roughness and vertical wall on wave overtopping in rubble mound breakwaters. The main governing parameters used in this study were the vertical wall height, variation of the tetrapod weights, initial water level elevation, and the volume of overtopping under constant wave properties. The experimental results showed that the roughness factor differed according to the tetrapod size. Furthermore, the overtopping discharge with no vertical wall was similar to that with relatively short vertical walls (${\gamma}_v=1$). Therefore, the experimental results highlight the importance of the height of the vertical wall in reducing overtopping discharge. Moreover, a large tetrapod size may allow coastal engineers to choose a shorter vertical wall to save cost, while obtaining better performance.
박상길,Asgar Ahadpour Dodaran,한종수,Mohammad Ebrahim Meshkati Shahmirzadi 대한조선학회 2014 International Journal of Naval Architecture and Oc Vol.6 No.4
Rubble mound breakwaters protect the coastal line against severe erosion caused by wave action. Thisstudy examined the performance of different sizes and properties (i.e. height of vertical wall and tetrapod size) of rubblemound breakwaters on reducing the overtopping discharge. The physical model used in this study was derived based onan actual rubble mound in Busan Yacht Harbor. This research attempts to fill the gap in practical knowledge on thecombined effect of the armor roughness and vertical wall on wave overtopping in rubble mound breakwaters. The maingoverning parameters used in this study were the vertical wall height, variation of the tetrapod weights, initial waterlevel elevation, and the volume of overtopping under constant wave properties. The experimental results showed thatthe roughness factor differed according to the tetrapod size. Furthermore, the overtopping discharge with no verticalwall was similar to that with relatively short vertical walls ( 1 v γ = ). Therefore, the experimental results highlight theimportance of the height of the vertical wall in reducing overtopping discharge. Moreover, a large tetrapod size mayallow coastal engineers to choose a shorter vertical wall to save cost, while obtaining better performance.