Introduction: Lasers and optics have been used extensively in dental procedures in recent years, and realizing the optical properties of the tooth is also an essential in its successful applications. The aim of this study was to compare the absorption and transmission of applied wavelengths in the range of 190–, 1100 nm at different dentin thicknesses and the effect of changing the direction of radiation emission on the dentin tubules. Methods: There were fifteen dentin specimens with thicknesses of 300, 600, and 1000 mm, five specimens for each thickness, prepared through a transverse section of the coronal dentin over the pulpal roof area of human molars. Considering the coronal-apical and apical-coronal directions, we measured the absorption and transmission of parallel light rays perpendicular to the dentin samples in different thicknesses and two directions with a Cecil CE 7400 UV/Vis spectrometer. Data analysis was performed using SPSS software version 19. P value < 0. 05 was considered significant. Results: The absorption rate of the ultraviolet wavelength range was significantly higher than that of visible and infrared light irradiation from both directions at three thicknesses (P < 0. 001). The radiation shift direction had no significant differences in the absorption and transmission of wavelengths of ultraviolet, visible, and infrared light in any of the three thicknesses (P > 0. 05). Conclusion: Accordingly, attenuation or transmission losses of light in the ultraviolet to infrared range clearly depend on the wavelength of light and the optical properties of dental dentin, and the thickness of the dentin used in this study has a little effect.

The present study describes the radiation-induced effects on nutritional quality and on anti-nutritional factors of sorghum grain: effects of electron beam (ER) and gamma irradiation (GR) at doses of 10, 20 and 30 kGy and infrared irradiation (IR) at 60, 90 and 120 s on the chemical composition, mineral content and bioavailability, in vitro protein and starch digestibility, total phenolic compound, phytate and tannins contents of sorghum grain, were investigated. The results showed that chemical composition were unchanged (P>0.05) by the irradiations. GR, ER and IR resulted in an increase in the digestibility of starch by 3.8, 5.4 and 6.8%, respectively. In vitro protein digestibility was reduced by 23% in IR, where as GR and ER increased crude protein digestibility of sorghum grain by 6.6 and 5%, respectively (P>0.05). The levels of phytic acid and tannins were significantly reduced by irradiations while the total phenols were increased relative to unprocessed control samples. The results indicated no substantial change in mineral content and bioavailability amongst the sample, with exception of significant (P>0.05) increase in extractable calcium, phosphorus, zinc and iron.

Introduction: Clinical performance of light cured resin composites is related to their degree of polymerization. The purpose of this study was to compare the degree of conversion of packable and hybrid composites by FTIR (Fourier Transform Infrared Spectroscopy).Materials & Methods: In this experimental study, 40 composite disks were prepared in two groups from Z250 and P60 composites. Each group was divided into four subgroups (2mm thickness cured with QTH unit, 2mm thickness cured with LED unit, 5mm thickness cured with QTH unit, and 5mm thickness cured with LED unit). Then samples were evaluated by FTIR to determine the degree of conversion (DC). Data were analyzed by Kolmogorov-Smirnov and three way ANOVA.Results: There was not a significant difference among the DC of the materials tested. LED significantly increased the degree of conversion of materials tested (P<0.001). DC values were significantly greater in 2mm diameter samples vs 5mm ones (P<0.001).Conclusion: The use of incremental technique in deep cavities restored with these composites is suggested. Also using LED is advised for curing composites because of a better result.

The objective of this study was completed to evaluate the effects of electron beam irradiation (EBI) at doses of 20 and 40 kGy and infrared irradiation (IR) for 90 and 120 second on ruminal degradation of dry matter (DM) and crude protein (CP), and Metabolizable protein (MP) of safflower meal (SM) by nylon bags technique. Three ruminally fistulated Dashtyari cows with an average live weight of 297±10 kg were used. The result of experiment showed that chemical composition of SM was affected by radiations(P<0.01). EBI and IR increased rapidly degradable fraction (a) and slowely degradation fraction (b) of DM and CP (P<0.01). Effective degradability of DM and CP was increased by EBI and IR compared to untreated SM. IR increased rumen undegradable protein (RUP) at ruminal outflow rate 0.02, 0.05 and 0.08/h. The highest values of MP was observed by irradiation of SM with IR for 120 seconds (P<0.01). According to results of this study, irradiation of SM with IR for 120 seconds relative to other treatments had better effect on increasing of RUP and MP and improving of quality of safflower meal.

Background and Aim: Disk herniation is one of. the causes of low back pain that 90% of people experience this pain. There are many pharmacological and non-pharmacological methods to alleviate the low back pain, such as physiotherapy techniques (infra-red and hot pack, etc.). In this study we investigated the effect of infra-red and hot pack on the low back pain associated with disk herniation.Material and Methods: In this experimental study, 60 patients with disk herniation were selected and divided randomly into infra-red and hot pack groups. Severity of the pain was measured on the basis of a numerical rating scale up to 10. Intervention was performed three times a week for one month. Severity and duration of pain were measured before and after intervention. SPSS software was used for data analysis.Results: The results of this study showed that the mean scores of pain severity and duration in infra-red group was 65.67±8.33 minutes which decreased to 44.33±5.60 minutes after intervention. The respective values for the hot pack group were 81±8.6 and 50.33±5.60 minutes before and after intervention. Effect of infra-red and hot pack on pain reduction was the same after intervention but infra-red was more effective in reducing the duration of pain.Conclusion: Considering the effect of infra-red, it can be recommended for pain reduction as a safe non pharmacological method. Hot pack is also effective in reducing pain by producing humid heat and patients’ compliance with this method will be higher.

Background and Objective: The aim of this study was to evaluate the diagnostic ability of CBCT to detect external root resorption.Subjects and Methods: External root resorption defects of different sizes and in different locations were simulated in 60 human mandibular incisors. Cavities simulating root resorption defects of small size (0.3´0.6 mm), medium (1.2´0.6 mm) and large (1.8´0.9 mm) were drilled in the cervical, medial and apical thirds of buccal surfaces. The teeth were divided in random groups and mounted in the mixture of acryle and dryed skull sheep powder. CBCT scan was used to evaluate external root resorption in 180 root thirds by two blinded observer. Statistical analysis was done with Kappa test.Results: Sensitivity of CBCT to detect external root resorption was 89% and the specificity was 99 %.The most defects that was detected were on the medial root thirds and the lowest defects that were detected were on the apical root. The percentage of small defects detection was 80%.Conclusion: CBCT technique is a very good method to evaluate external root resorption with high sensitivity and excellent specificity. It can detect the defects as small as 0.3mm.

In this paper, an alternative approach in operational modal analysis is presented, utilizing image processing technique and transmissibility functions. Imaging sensors do not impose additional mass on the structure due to their non-contact nature, while transmissibility functions, independent of excitation type, can directly extract mode shapes. The innovation of this research lies in combining these two techniques to record dynamic responses and identify modal properties. To capture the temporal response history from video signals, the block-matching method with sub-pixel accuracy was employed. Validation was conducted by recording the response of the tip of a cantilevered steel beam subjected to impact excitation, using a high-speed camera and a laser vibrometer, simultaneously. The RMSE plots in the time domain and the PSD in the frequency domain indicate high accuracy of this method. Using this approach, the displacement time histories of various points on the structure were extracted from the video signals, and the modal properties, including natural frequencies, damping ratios, and mode shapes, were identified using the transmissibility matrix method. The results obtained from the proposed method were compared with the stochastic subspace identification (SSI) method and analytical solutions. The findings reveal the accuracy of the modal identification approach introduced in this article. The highest relative error in estimating the natural frequencies of the first and second modes, compared to the values from the laser method, are 0.19% and 0.13%, respectively, and in comparison to the analytical values, they are 0.34% and 1.5%, respectively.

Background & Aims: The aim of this study was to evaluate the accuracy of Cone-beam Computerized Tomography (CBCT) linear measurements in dry mandibles by comparing them with direct measurements.Methods: Two human dry mandibles were used in this study. Thirteen sites were selected on each mandible. Specimens were scanned by CBCT and linear measurements were made using Planmeca Romexis 2.3.0.R software. Mandibles were cut into sections at marked locations and the same distances were measured by a digital caliper. Differences between two methods were assessed using paired t- test.Results: The mean differences for bone height, bone width and the crest-canal distance between CBCT and digital caliper measurements were -0.47±1 mm, -0.14±0.78 mm and 0.00±0.76 mm respectively. The differences were only, significant for bone height measurements (P<0.05). There was a high carreltion between the result of CBCT and gold standard.Conclusion: The results of this in-vitro study on mandible indicate that, although there is a statistically significant difference for bone height measurements between the two methods, the difference is not significant in clinical applications. Thus, CBCT was shown to be a useful technique for preoperative dental implant planning.

Near-infrared spectroscopy (NIRS) is a spectroscopic method that uses the near-infrared region of the electromagnetic spectrum. Typical applications include medical and physiological diagnostics. NIRS can be used for non-invasive assessment of brain function through the intact skull in human subjects by detecting changes in blood hemoglobin concentrations associated with neural activity, e. g., in branches of cognitive psychology as a partial replacement for fMRI techniques. NIRS cannot fully replace fMRI because it can only be used to scan cortical tissue, where fMRI can be used to measure activation throughout the brain. In this approach we compared NIRS with different functional brain tests.