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Showing 3 results for Saraf

Mohamad Saieed Sheykhrezaie, Pegah Saraf, Mohamad Hosein Nekofar, Alireza Mohamadi,
Volume 25, Issue 4 (9 2013)

Background and Aims: The purpose of this study was to evaluate the sealing ability of different thicknesses of orthograde MTA plugs in comparison with 5 mm gutta-percha.

Materials and Methods: Fifty extracted single rooted human teeth were collected. After root canal preparation, the samples were randomly divided into 4 experimental (n=10) and two control groups (n=5). In group 1, the apical 5 mm of the canals were obturated using laterally condensed gutta-percha and sealer AH26. Groups 2, 3 and 4 received 2, 3 and 4-mm thick orthograde MTA plug, respectively. Thereafter, the coronal portion of specimens was exposed to the microbial solution containing streptococcus sanguis and the root tips were placed in phenol red lactose broth. The color changes were observed within 60 days. The data were analyzed with Fisher exact test.

Results: The leakage was found in all samples (100%) in group 1 and 72.7%, 30.8% and 50% of the samples in groups 2, 3 and 4, respectively. Significant difference was found between 3 mm thickness of MTA plug and gutta percha and sealer (P=0.02).

Conclusion: According to the findings, it seems that 3 mm thickness of orthograde MTA plug had better sealing ability than the other thicknesses of MTA plug as well as the 5 mm of gutta-percha.

Adel Pirjamali Neisiani, Nima Jamshidi, Mohsen Saraf Bidabad, Navid Soltani,
Volume 28, Issue 4 (1-2016)

Background and Aims: Optimization drilling parameters in order to temperature decrease during creation of hole in the bone is an interested issue. The aim of this study was to achieve optimum values of drilling parameters based on the creation of minimum temperature during jawbone drilling.

Materials and Methods: In this study two models of mandible and maxilla was created and teeth 2, 5 and 8 from maxilla and teeth 25, 28 and 31 from mandible were removed. The drilling operation was performed under different conditions on jawbone models using finite element analysis and the maximum temperatures were measured in adjacent of holes.

Results: Drill bit head angle of 70 degrees was created the lowest maximum temperature during drilling operation. The lowest maximum temperatures were observed in the drill bit rotational speed, drill bit feed rate and the force exerted on the drill bit equal to 200 rpm, 120 mm/min and 60 N, respectively. The use of irrigation can decrease the maximum bone temperature about 7ºC. The maximum temperature differences in various regions of mandible and maxilla were approximately about 1ºC.

Conclusion: Sharpness of drill bit head angle, reduction of drill bit rotational speed, increasing drill bit feed rate and exerted force on drill bit and also the use of irrigation played effective roles in temperature decrease during jawbone drilling. Drilling site did not have important effect on the temperature changes during jawbone drilling.

Adel Pirjamalineisiani, Mohsen Sarafbidabad, Nima Jamshidi,
Volume 29, Issue 3 (10-2016)

Background and Aims: Improving dental implantation conditions in order to reduce the failure is always desirable for researchers. The aim of this study was to compare two different materials of dental implants from the viewpoint of biomechanical effect after placement and loading in the mandible.

Materials and Methods: A 3D model of mandible was designed in the MIMICS 10.01 software. Then, by using the obtained model, the end part of the mandible was designed in CATIA V5 software and a drilling operation was performed on the cortical bone of mandible by finite element analysis simulation method in DEFORM-3D V6.1 software. Thereafter, the 3D model of created hole was extract from the drilled site and an ITI dental implant model designed in the CATIA V5 software, was placed in the hole. The space remained between the implant and cavity was considered as a newly-formed cortical bone in drilled site after 6 weeks of dental implant placement and the mechanical properties of newly-formed bone were entered to DEFORM-3D V6.1 software. Then, a load was applied on the top surfaces of two dental implant models with the materials titanium and zirconium-2.5% niobium.

Results: The emerged volume changes in newly formed cortical bone around Ti and Zr-2.5 Nb dental implants were measured 0.238 and 0.242 percent, respectively. Furthermore, micro-motion of Ti and Zr-2.5 Nb dental implants were measured 0.00514 and 0.00538 mm, respectively.

Conclusion: The results of this study showed that Ti dental implant created better conditions than Zr-2.5 Nb dental implant in the mandible.

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