فهرست مطالب samira shahsiah

Cryogenic methods have been used to increase the wear, abrasion, corrosion resistance and to improve the strength of metals. The aim of this study was to evaluate the effect of cryogenic treatment on the cyclic fatigue resistance of rotary nickel‑titanium (NiTi) instruments.

In this in vitro study, 20 Hyflex (Coltene, Altstätten, Switzerland) nickel‑titanium instruments, size 25, 0.06 taper, were randomly divided into two groups as follows: untreated NiTi rotary files (Group A) and cryotreated NiTi rotary files (Group B). The instruments of Group A were completely immersed in a cryocan containing liquid nitrogen (–196°C) for 24 h. After 24 h, the instruments were removed from the bath and were allowed to return to room temperature gradually. All files were used (at a speed of 500 rpm and a torque of 2.5 Ncm) in an artificial canal with a 60° curvature until fracture. Time to failure was recorded with a stopwatch in seconds and subsequently converted to number of cycles to fracture (NCF). Groups were compared using the independent‑samples t‑test. The level of statistical significance was set at 0.05.

Mean NFCs in Group A and B were 1576 and 1395, respectively. However, statistical analysis showed that there was no significant difference between the groups (P = 0.2).

Deep cryotherapy of NiTi endodontic files cannot improve the cyclic fatigue resistance of HyFlex files, but further studies are required to evaluate these cryogenically treated NiTi files clinically.

Chemotherapy is one of the most common treatment modalities for blood malignancies such as leukemia, with several potential complications. Mucositis is one of the complications of chemotherapy, manifested with different severities. The aim of this study was to evaluate the prophylactic effect of vitamin E on reducing the severity of chemotherapy-induced mucositis.
This randomized clinical trial was performed in Ahvaz’s Shafa Hospital on 56 leukemic patients, undergoing chemotherapy. The patients were divided into 3 groups: 1) systemic treatment group, case group 1; 2) topical treatment group, the case group 2; and 3) control group. The oral mucosa of the patients was evaluated for the severity of mucositis and the patient’s response to pain. Data were analyzed with Mann-Whitney test and t-test (α = 0.05).
In relation to the severity of mucositis, based on the results of Mann-Whitney test, there was a significant difference between the case group 2 and control group (p value ≤ 0.01). There was no significant difference between the two case groups (p value = 0.2). In relation to the patient’s response to pain, there was a significant difference between the case group 2 and control group (p value ≤ 0.01). There was no significant difference between the two case groups (p value = 0.4). Therefore, vitamin E decreased the incidence of thermotherapy-induced mucositis.
Within the limitations of this study, vitamin E in its topical form is an effective medicament for reducing the severity and pain of chemotherapy-induced mucositis.

Mineral Trioxide Aggregate (MTA) has a high clinical success rate when used as the apical plug. The conventional method of using MTA as an apical plug is doneduring two treatment sessions. This study aimed to evaluate the possibility of complete filling of root canal with gutta percha and AH26 sealer immediately after the placement of MTA plug. A total of 88 single-rooted teeth were selected for this experimental study. The teeth were prepared and randomly divided into two groups of 40 each. Four teeth were considered as the positive control group and the remaining 4 as the negative controls. In group 1، MTA apical plug was placed، specimens were stored in saline solution for 24h and then filled with gutta percha and AH26 sealer. In the 2nd group، the roots were filled immediately after the placement of MTA. In the positive control group، the root canals were left unfilled and in the negative control group، root canals were filled with gutta percha and sealer. The specimens were then immersed in 1% methylene blue، demineralized in 5% nitric acid and cleared in methyl salicylate. Dye penetration was measured by a stereomicroscope in micrometer. T-test was used for statistical analysis. The mean dye penetration was 7813 μ m in the first and 9152 μ m in the second group. According to t-test، the 2nd group had significantly greater microleakage than the first group (P<0. 05). MTA needs to be exposed to moisture for final setting and root canal obturation must be delayed until complete setting of MTA.

Internal root resorption (IRR) in early stages، may have no radiographic facing. For evaluating of these lesions، intraoral periapical radiography is ususally used. One of the most limitations for this method is its low diagnostic detective information power. The aim of this study was to compare the diagnostic accuracy of cone beam computed tomography (CBCT) with periapical radiograghy in early internal root resorption. Subjects and Sixty single root premolar teeth were cut mesiodistal and devided randomly into two groups (30 teeth in each). The test group was subjects to artificial IRR in coronal and apical region by round bur. The control group was left untreated. The samples were manted on self cure acrylic resin. CBCT and periapical radiography captured from all teeth. Two blinded radiologists assessed the presence or absence of IRR in each tooth. Complete agreement in diagnois and prescence of IPR was made by CBCT. However، with periapical radiography only 1/3 of apical lesions were diagnosed. The finidengs of this study demosmntrated that CBCT has a higher accurcy in detecting internal root resorption lesions particularly in apical sites than periapical radiography.

White MTA، and Portland cement have similar chemical structures. The aim of this study was to evaluate the inflammatory reaction of rabbit bone tissues to implanted white MTA، and Portland cement. Subjects and In this in vivo study، twenty 1-year old male Iranian rabbits (experiment white Specie)، were divided into 5 groups (4 in each group). After preparation of 3 holes (distance 2 cm- depth and diameter 2 mm) in tibia، the allocated groups received an intra-bony implant of the test materials (White MTA، or Portland cement) and the third hole، with no implant، was created to evaluate inflammatory reaction related to surgical trauma. Samples were processed for histological study after 7، 15، 30، 60، and 90 days. Furthermore، blood samples were taken for evaluation of systemic inflammation for ESR test. The results were analyzed using Kruskal-Wallis and Mann–Whitney tests. At similar time points، statistical analysis revealed significant difference between implanted material (white MTA، Portland cement) in the first and second holes with control hole due to bone tissue reaction but pair-wise evaluation Between all of implanted material found no significant differences. In different times bone tissue reaction showed significant differences. The finding of this study demonstrated a similar tissue compatibility between both implantable materials and improvement of tissue healing occur with similar time profile after material implanting.

Recurrent aphthous stomatitis (RAS) is the most common oral mucosal inflammatory disease، with unknown etiology. Antioxidants are able to preserve molecules from damage and also can delay the start of RAS. The aim of this study was to determine serum level of vitamin A as an antioxidant in RAS patients compared with normal subjects. The total 38 subjects were divided into two groups of 19. One group consisted of aphthous patients and the other comprised of healthy subjects. The groups were matched by sex and age. Serum levels of vitamin A were measured in both groups. Finally data were analyzed with T tests. The mean and standard deviation of serum vitamin A was 13. 63±2. 3 µg/ml in RAS group and 23. 9±4. 5 µg/ml in control group. There was a significant difference between the two groups (p<0. 05). It was shown that serum levels of vitamin A in RAS patients were lower than that of normal individuals.

Recurrent aphthous stomatitis (RAS) is the most common oral mucosal inflammatory disease. The frequency of RAS is as much as 20% in the general population. The cause of RAS is not yet fully understood. Antioxidant is a material which has ability to preserve molecules from damage and also can delay the start of it. The aim of this study was to compare saliva level of total antioxidant status (TAS) in RAS patients with that of normal subjects. In this case-control study, 25 patients with aphthous stomatitis were considered as the case group and 25 healthy subjects as control group. The case and control groups were matched by sex and age. Total antioxidant status (TAS) saliva levels were measured in two groups by spectrophotometer. The data were analyzed with independent sample t-test. The mean and standard deviation of TAS in case group was 1.64±0.64 µmol/L and in control group was 1.49±0.3 µmol/L. There was not significant difference between case and control groups (P=0.464). Results of this study showed that there was no statistically significant difference between RAS patients and healthy subjects in saliva antioxidant status levels.

Mineral trioxide aggregate is being widely used for root end filling, pulp capping, perforation repair, and other endodontic procedures. Recently, a material similar to ProRoot mineral trioxide aggregate (PMTA) was developed in Iran named Root mineral trioxide aggregate (RMTA) with the claim of having the exact result of original MTA. The purpose of this study was to compare the amount of cell cytotoxicity of RMTA with PMTA at three different time periods using scanning electron microscopy (SEM) as well as the amount of cell viability at the above mentioned period. Three culture plates in each group were packed with a homogenous layer of PMTA and RMTA prepared according to manufacturers instruction. A plate of media without any material was used as control in each group. The material set for 72 h in CO2 incubator and 2x10 of fibroblast L929 was added to each plate. SEM evaluation with x800-3000 magnification and cell viability counting using trepan blue counting method were done after 48, 72, and 168 hours. There was no significant difference between cell viability of PMTA and RMTA, although the amount of cells remained viable in PMTA group was higher at 48 and 168 hours while for RMTA, it was higher after 72 hours. The SEM evaluation showed that PMTA compared with RMTA has less porosity, but relatively similar amount of cell coverage was detected for both materials after 168 hours. ProRoot and Root MTAs showed comparative biocompatibility while evaluated in vitro. The results suggest that RMTA can be used as an alternative for PMTA in clinical trials.