Esthetic is a natural necessity among all human beings, and the reconstruction of the natural features of prosthesis is considered an important aspect in dentistry. Reconstruction of the natural features in removable prosthesis by characterization of denture base is one of the most important factors. In this regard esthetic, in removable prostheses, is achieved through different techniques such as: tooth selection and arrangement, designing the denture base and acrylic base color. The final goal for all these effects is to achieve a natural appearance for denture. However, other factors such as treatment limitations, different personal needs and general health principles, should be taken into consideration. This article not only reviews the natural appearance of oral mucosa that is replaced by the denture base, but also discusses about the materials used in tinting acrylic denture base and their application techniques.

Due to the sharp reduction in budget of civil projects and road construction, the need to use local soil as the base is felt as a way to reduce the final cost of projects. Therefore, this research examines the characteristics of untreated and treated base soil with 3% lime, including uniaxial compressive strengths and indirect tension (Brazilian) test and resilient modulus with different curing times, as well as after performing tests of wet-dry cycles and freezing-thawing. Uniaxial and Brazilian samples with a diameter of 10. 1 cm and a height of 11 cm were made in 3 layers with the same thickness and dry density of 2. 2 g/cm3 and initial moisture of 6% and 8%. The results show that the addition of lime significantly increases the CBR values and shear strength of the soil. Soil treatment with lime improves its resistance against wetting-drying cycles, but it is not suitable against freezing-thawing cycles. Also, based on the tests to determine the resilience modulus, a comparison was made to determine the relationship between CBR values of untreated and treated soil with lime under hot-dry weather conditions. The results showed that the modulus values of dry untreated soil and lime treated soil are equal. The CBR value (maximum value based on penetration of 2. 5 mm or 5 mm) in untreated soil is equal to the same value for penetration of 1. 25 mm in lime treated soil. Therefore, for design purposes, it is recommended to use correlation relations of resilience modulus and CBR values for penetration of 1. 25 mm for soil treated by lime.

It is possible to use reclaimed asphalt pavement materials as a type of recycled material in the asphalt concrete layer or the base layer in the pavement. However, due to the variety of sources as well as insufficient strength, RAP materials without stabilizing additive is not suitable in granular base layers. In this paper, the unconfined compressive strength of cement treated RAP base has been investigated and evaluated in a laboratory study. Three cement contents of 4, 5, and 6 percent were added and the samples were cured for 3, 7, 28, and 90 days after compaction. Samples were prepared with standard compaction energy according to ASTM D558. The unconfined compressive test has been carried out using the strain control method. In order to investigate the effect of moisture, in addition to the optimum moisture, moisture levels below and above the optimum have also been evaluated. Based on the results of this laboratory study, with the increase of cement percentage and curing period, unconfined compressive strength and modulus of elasticity increase visibly. It was also found that according to the percentage of cement used in the mixing design, the maximum strength may occur at the optimum moisture or less than the optimum moisture content.

This study has evaluated the unconfined compressive strength (UCS) of the cement-treated base (CTB) containing 100% reclaimed asphalt pavement (RAP) aggregates using different-age samples. The samples were prepared with standard and modified compaction energy based on ASTM D558 and ASTM D1557. Three cement contents of 4, 5, and 6 percent were added and the samples were cured for 3, 7, 28, 56, and 90 days after compaction. The unconfined compressive test has been carried out using the strain control method. In order to investigate the effect of moisture, in addition to the optimum moisture, moisture levels below and above the optimum have also been evaluated. Based on the results of this laboratory study, with the increase of cement percentage and curing period, unconfined compressive strength increase visibly. Next, indirect tensile strength (ITS) test was performed on the selected samples (mentioned ages) and the results showed that the curing period and cement directly affected and increased the tensile strength. Results indicated that the curing period and the compaction method had the greatest and least effect on the UCS, respectively. Finally, the UCS and ITS results showed that it is possible to use 100% RAP aggregates in the CTB layer.

In recent decades, using recycled asphalt materials in pavements is considered by researchers due to their economical costs. The purpose of this laboratory experiment is to introduce optimum mix design including suitable grading limits of the mixture, moisture formula for estimation of the amount of water needed for compaction and finally investigating the effect of reclaimed asphalt pavement (RAP) on unconfined compressive strength (UCS) of different cement-treated base mixtures and determination of optimum RAP content and cement with lowest construction cost. For this purpose, first, grading properties of different materials and RAP were determined and proper grading was selected. For studying the compaction characteristics and determining optimum moisture content, 12 different mixture designs, as a combination of 4 RAP percentage (0, 40, 60 and 80) and 3 cement content (3, 5 and 7 percent) were constructed. Then, 15×30 cm cylindrical samples were constructed to investigate UCS properties at optimum moisture content. Results showed that grading limits in Iran's Road Bulletin No.101 could be the main reference for cement treated base (CTB) mixtures containing RAP materials. Also, modeling results of optimum moisture content indicated that by adding more recycled asphalt materials to the mixture would increase optimum moisture content and reduce maximum dry density. The UCS tests undertaken on 7-day cured samples at 25 0C indicated that by increasing the RAP materials to the treated mixture would decrease UCS of the samples. The pavement containing 68% of reclaimed asphalt and treated with 5% cement was the most economical mixture considering the 3.8 Mpa limit of UCS index. Finally, it could be expected that instead of compacting the samples with standard hammer, 60 seconds of vibration compression may be used.

The present paper investigated the dynamic and durability characteristics of silty-sand soil used in the base layer treated with cement and a mineral polymer via a series of laboratory tests.The specimen selection for the cyclic triaxial test was based on the results of the uniaxial compressive strength, Brazilian tensile, wetting-drying and freezing-thawing cycles tests. The results showed that, the compressive strength of the cemented soil can be reached in the shorter period of times and volume loss of the cement specimen may be eliminated due to the use of polymer. The compressive strength of the treated specimen with 6.3% cement and 0.7% polymer and has been selected as the optimal combination. In the durability test, the cement-polymer specimens show a better performance than cement specimens, and this trend is more noticeable in wetting-drying cycles than freezing-thawing cycles. In the next step, the cyclic triaxial test was performed on four optimal combinations with treated cement and cement-polymer. An increase in frequency raises the resileient modulus and damping ratio, while it has decreased the axial strain. For AASHTO T307 stress level, the mean values of the resilient modulus of cement-polymer specimen were higher than cement specimen in two curing modes. Meanwhile, for damping ratio parameter, the cement specimen show a better performance than cement-polymer specimen. Generally, soil treatment with the cement-polymer specimen demonstrated a relative advantage over the cement-only specimen in the medium stress range for the base layer in wetting-drying mode (as defined by stress levels in AASHTO T307 standard).

Introduction: Correction of deep overbite and achieving a long-term stability are still major concerns for many orthodontists. There are three main ways for solving this problem: Bypass arch technique introduced by Ricketts, Segmented arch technique introduced by Burstone and using TADs. The aim of this study was to evaluate and compare the effects of Ricketts and Burstone techniques during correction of deep overbites.Materials and Methods: In this clinical trial, 18 female patients with Cl I and II occlusion and more than 4 mm of overbite were selected. The subjects were divided into two groups (n=9). The deep overbite in group A was treated with Ricketts technique and Burstone technique was used for correction of overbite in group B. Fifteen jaws were included in each group. Lateral cephalograms before and after intrusion were used to evaluate the results. Data were statistically analyzed with Student’s t-test and SPSS 18 (a=0.05).Results: There was a statistically significant difference in the means of true intrusion and extrusion between groups A and B (p value=0.014 and p value=0.47, respectively). However, overbite reduction was not significantly different between the two groups (p value=0.704). In addition, the differences in mean false intrusion (p value=0.02), changes in the axial inclination of posterior teeth (p value=0.047) and the angle between axial inclination of upper and lower anterior teeth (p value=0.002) were statistically significant between the two groups.Conclusion: Under the limitation of the present study, the results confirmed the superiority of Burstone technique in intruding incisors with less undesirable lateral movements.