ABSTRACT
Low Level Laser Therapy is used in many aspects in medicine and dentistry, such as treatment of bone lesions. The purpose of this study was to evaluate the effect of low level laser [GaAlAs] combined with the application of DFDBA in bone healing of rabbit tibia. The experimental study was done on 12 male albino rabbits with an approximate weight of 1.5 kg and about 6 months of age. In order to perform the surgery, animals were anesthetized with intravenous injection of Ketamin 10% and Xylazine 2%. An artificial lesion was created using implant drills [height of 4 mm and diameter of 2.8 mm] in tibia bone and was filled with DFDBA. Then, the lesions were irradiated using laser with distinct protocol [10 days irradiation, 14 days rest, 10 days irradiation, 14 days rest]. Type of the laser was GaAlAr with wavelength of 808 nm, energy of 6 J/cm[2] and in continuous mode. No irradiation was done in the control group. After 48 days, the animals were sacrificed and sections from tibia was made and the specimens were underwent histological assessments. Wilcoxon signed rank test was performed for evaluating the data. In histological assessment, laser group showed significantly more osteogenesis and angiogenesis [P<0.05]. The findings of the present study show that GaAlAs irradiation together with the application of DFDBA led to improved healing, more angiogenesis, and osteogenesis in bone lesions of rabbit
ABSTRACT
Ni-Ti alloys are widely used in orthodontics. The aim of this study was to evaluate and compare the load- deflection properties of Ni-Ti wires. In this experimental study, 65 Ni-Ti round wire [0.014 inch] from 13 different brands were subjected to a 3-bracket bending test at 37°C using an upper central bracket attached to rod in a manner the distance between the midpoint of brackets was 15.5mm. For each wire, the average force was determined at 1, 1.5, 2 and 2.5 deflections in unloading area. Then, SEM equipped with EDX system was used to asses element composition of each brand of wire. The drawing graphs had the overall shape of superelastic graphs;however, the amount of force applied by different wires at different deflections were significantly different, so 13 wires was divided to 4 categories according to their force delivary: high force [orthoforce], moderate force [Proflex, ORG, Ortho technology IMD, GAC and Force I], Low force [Smart' Nitanium' Nitinol SE, SE NITI, Rematitan Lite] and very low force [Imagination]. Additionally it was revealed that wires belong to one manufactory doesn't act similarly. The maximum and minimum Coefficient of Vriation belonged to Ortho Force and ORG, respectively. In element analysis, the ratio of Ni/Ti was not similar in different wire brands. It seemed likely that wires with higher Ti atomic percentage show lower load-deflection rate. It is revealed by this study that although studied wires almost showed superelastic graphs, the slope of the graph showed significant difference among the wires. So in this regard, the manufacturers' propagations are not reliable completely. The general recommendation is application of caution and precision in wire selection and attention to study results, element analysis and amount of crowding
Subject(s)
Nickel , TitaniumABSTRACT
Compared to the information about educational responsibilities, there is not much information about the research skills and activities of the academics in dental schools. The aim of this study was to evaluate the research performance of the academic staff of the dental schools and their educational needs to promote their research skills. This cross-sectional study was done by mailing a questionnaire to all of the members of Iran dental faculties. The questionnaires contained personal information like age, sex, place of employment, educational records, and additional questions like the workshops previously attended, and interests to attend certain workshops. To evaluate the research performance of the academic staff, the number of accomplished researches, the articles published in known national and international journals, their skills in using internet, and the number of attended workshops about research methodology were included in the questionnaire. The completed questionnaires were gathered and evaluated by descriptive statistics. From the questionnaires gathered, 436 were eligible to be included in the study, which formed 58% of the academic staff of dental schools. The results showed that 7.4% of the staff had more than 10 researches conducted, 15% had 5-10, 49.9% had less than 5, and 27.7 had no researches done. Considering the articles published in known national journals, 28.2% had no papers, 51.8% had 1-5 papers, and 20% had more than 5 papers. Regarding the number of articles published in known international journals, 77.5% had no papers, and 20.2% had 1-3, and 2.3% and more than 3 papers. The "preliminary research methods" workshop had the highest percent of participation [71.6%], and "Stata acquaintance" workshop had the least [0.7%]. The participants were mainly interested to participate in three workshops, "English scientific writing" [26.3%], "principles of scientific writing" [17.5%], and preparing research proposals" [16.2%], respectively. We concluded that the research skills and performance of the academic staff, though improved in the recent years, is still unsatisfying. In order to promote it, it is recommended to organize workshops about "research methodology", "scientific writing" and "preparing of proposals"