Introduction: Long-term clinical evaluation of dental implants and their surrounding structures is of utmost importance to acquire knowledge about reasons for implant success and failure.However, accurate and reproducible results are difficult to obtain. The aim of the present study was to examine bone height around endosseous implants on Digital conventional radiographs (DCR) and direct Digital subtraction images (DSI) prior to loading.Materials and methods: In this experimental study, bone height around 10 implants in 6 patients was assessed by 2 observers. Standardized Digital radiographs were obtained just a week and 3 months postoperatively and subtracted by means of EMAGO software. Then the observers evaluated bone height on DCRs and DSIs. MINITAB software and paired t-test were used for statistical analysis (a=0.05).Results: Comparative evaluation of bone height indicated significantly higher values on DCR than on DSI (p value=0.002). The observers also had statistically significant variability in this assessment (p value=0.00003).Conclusion: DSI demonstrated lower values of linear measurement of bone height around endosseous implants compared with DCR. Interobserver variability should be considered when comparing values from follow-up studies.

This paper is based on a research study conducted among 361 students of various disciplines of social sciences from Al-zahra, Tehran, Tarbiat Moalem, Shahid Beheshti and Allameh Tabatabaei Universities. The purpose of this study is to evaluate the relationships and interactions of students with one another in different domains including social and educational fields. The theoretical framework of this research study is based upon the view points of theorists of sociology of science, according to which the role of students' interactions as well as group activities are examined with respect to their formation of motivation, emotional energy and social and disciplinary Activism. The findings of this study will help proving some of the theories developed in the field, according to which one can conclude that the greater the students' social integration, the greater their interactive learning. Such students have stronger motivation and emotional energy and are more satisfied with their major and professors. The more integrated the students, the greater progress they will make in their studies and the more self-efficacy they will develop. The main achievement of this study, taking account of effective variables, is thus to draw the attention of researchers and policy makers to the important role that social variables and factors, especially the space of student relationships play in educational progress and the creation and promotion of a sense of satisfaction among students, not to mention their degree of self-efficacy.      

Following the fall of Saddam Hussein in 2003 and the establishment of governments based on the people's votes, due to the long-standing religious and cultural ties between the peoples of Iran and Iraq, the ground for Iran's Activism in the geopolitics of this country was provided. Iran's regional policy, while observing the principles of good neighborliness and non-interference, has taken a special and strategic view of these developments and has acted in an effort to secure national interests. In this regard, three patterns regarding Iran's Activism in Iraq's geopolitics are proposed, which include the pattern of passive Activism or non-participation, interactive Activism, and Activism based on soft power and economic links. Examining these three patterns and the advantages and disadvantages associated with each one, and analysis regarding which pattern will be more likely to provide Iran's national interests are the main topics of this article. Based on the results of this research, Iran can have a unique position in Iraq's geopolitics due to its relative advantages compared to other actors. Based on this, an effective regional policy to deepen the relations between Iran and Iraq, on the one hand, is focused on social relations that are rooted in culture, religion, language and common race, and on the other hand, it is focused on deepening economic relations and establishing mutual dependence.  .

Background & Aim: The majority of carious lesions are not well-defined radiolucencies. Approximately 40% demineralization is required for radiographic detection of a lesion. The actual depth of penetration of carious lesion is deeper than may be detected radiographically. However, Digital subtraction images permit to detect 1-5% decrease of mineral mass per unit volume. The goal of the present study was to evaluate the accuracy of Digital subtraction radiography in the detection of dental demineralization in vitro.Methods & Materials: This study was based on observational-diagnostic method which was done on 30 extracted human teeth, categorized in two groups A and B, each having 15 members. In each of teeth, one approximal enamel demineralization lesion was induced using an acidified system (PH=4.8). Direct Digital radiography were obtained under standardized condition of teeth before demineralization. After 7 days, the teeth of group B and after 42 days, group A removed from acid and new radiographs were taken. The images of the 7th and 42nd days were subtracted from the baseline radiograph (before creation of the lesion). Then teeth were histologically evaluated. Direct Digital and subtraction images were interpreted by three observers to detect presence or absence of the lesion, then the diagnostic accuracy of both methods was determined.Results: After 7 days, the sensitivity, specificity, accuracy, positive predictive value and negative predictive value for incipient lesions in direct Digital radiography were 0%, 80%, 40%, 0% and 44% respectively and in Digital subtraction radiography were 66.7%, 86.7%, 76.7%, 83.4% and 72.3% respectively. However after 42 days the sensitivity, specificity and accuracy of both methods were 100%.Conclusion: Digital subtraction radiography has a fairly acceptable accuracy in detection ofthe incipient proximal lesions in comparison with DDR. For moderate proximal lesions DSR has the same accuracy as DDR.