Journal of Dental Medicine

Conclusion: According to the results of this study and the application of anaerobic conditions, forced anaerobic bacteria can be isolated from clinical specimens of oral infections and by Tetra Arms-PCR no significant relationship between TGF-1β genomic polymorphism and periodontitis was observed. In addition, therer was no significant difference in the frequency of alleles and genotypes between the control and patient groups.

Background and Aims: Today, academic stress and subsequent test anxiety is one of the most important problems for the last year of high school students. In addition to systemic effects, stress can affect the level of oral health by disrupting oral health behaviors. The aim of this study was to investigate the relationship between stress and variables related to oral health in the final year of high school students prior to University entrance exam.
Materials and Methods: In this descriptive-analytical study, the level of stress and variables related to oral health in 180 students of the final year of high school in Tehran, in three time periods during the academic year 2018-2019, were measured by a questionnaire and one clinical examination. Data were analyzed by Friedman, Bonferroni and Generalized Estimating Equations using SPSS software.
Results: As the exam approaches, some variables related to the oral health, such as toothbrush usage pattern, daily sleep, fast food frequency, and sweet snack consumption, changed (P<0.05). Daily sleep changes were significantly associated with the stress changes (P=0.022). According to the results of the Repeated Measures Analysis, significant changes were observed between the average score of the "Cognitive Error" aspect of three times (P<0.001). Also, according to the results of the Bonferroni Test, significant changes related to the difference in the average score of "cognitive error" 6 months and 3 months before the entrance exam (P<0.001), 6 months and 1 month before the entrance exam (P<0.001), and 3 months and 1 month before the entrance exam (P<0.001) were observed. In all three cases, as the time of the entrance exam approaches, the score of "cognitive error" had decreased significantly. Considering that the lower score in this index indicates a higher level of test anxiety, the closer we get to the entrance exam, the higher the level of test anxiety in the "cognitive error" dimension
Conclusion: The academic stress of the national university entrance exam can affect some oral health variables such as daily sleep, however, it is not related to other variables.

Background and Aims: Nowadays, the requirement of any policy-making at the national and regional level is to know the level of knowledge of people about oral health and ways to prevent dental caries.  This study examined the habits, actions and economic level of elementary school students in Qazvin city in 2017-2018.  Also, the effects of peer group social network on behaviors related to oral health and obesity was investigated in order to find the way for interventions making it more effective in this social group. Materials and Methods: In this descriptive-analytical study, 145 students participated. They were in the 3nd and 6th grades of elementary school in the academic year of 2017-2018. The questionnaire used in this study had 20 questions and 4 main sections. The main parts of this questionnaire included demographic characteristics, behavior and habits related to oral health, oral health knowledge of students and families, and socio-economic status. Data were collected through clinical examinations and through valid questionnaires and evaluated using SPSS and Excel software. Results: According to the results of Pearson's correlation analysis, a significant correlation was observed between the health knowledge scores of individuals and their friends between both groups of casual and close friends (P<0.01). The correlation between the knowledge of individuals and close friends was significantly stronger (P<0.01). Also, there was a significant relationship between socio-economic status and behaviors related to oral health (P<0.05). There was also a significant positive relationship between the number of times close friends brushing their teeth in a social network (P<0.001). This connection was not observed in the friends’ network. Conclusion: This study determined that close friends can be effective in determining the oral hygiene behaviors of elementary school students.

Background and Aims: The quality of sleep plays a significant role in the academic performance of dental students, especially in the clinical years. Identifying and treating students at risk of sleep disorders can reduce or limit the drop in academic performance. The purpose of this study was to determine the relationship between the sleep quality and educational performance of Rafsanjan dental Student-Iran.
Materials and Methods: The present study was a descriptive-analytical cross-sectional study that was conducted among all dental students in Rafsanjan University of Medical Sciences - Iran. This study was presented to all dental students in Rafsanjan by online questionnaire method on Pressline website. The questionnaire included demographic information and student number along with the Pittsburgh Sleep Quality Standard Questionnaire. The Pittsburgh Questionnaire examines the quality of sleep in the range of 0 to 21. The link of the questionnaire was made available to the students through Telegram, and the GPA of the total students was obtained by using the student number from the Vice-Chancellor of University Education. The data were analyzed with SPSS26 software. First, the data were analyzed with Smironov's kermograph test. The results of this test showed that the data distribution is not normal (P<0.05). Due to the non-normality of the data distribution, non-parametric tests such as K-score, Mann-Whitney, Kruskal-Wallis and Spearman were used.
Results: 151 students participated in the questionnaire of which, 73 were men (48.3%) and 78 were women (51.7%). The mean and standard deviation of the age of the subjects studied was 22.11±2.3 years. The overall average sleep quality score of dental students was equal to 8.13, which according to the questionnaire, students experience poor sleep quality. 86.1% of students had poor sleep quality. Examining the correlation between the sleep quality and academic performance showed that there was no significant relationship between them. Sleep quality had no significant relationship with gender, marital status, place of residence, and entry year (P<0.05).
Conclusion: The results of the present study showed that majority of dental students in Rafsanjan had low sleep quality. Although, there was no relationship between the quality of sleep and academic performance, it seems necessary to pay attention to the sleep status of these students in order to improve their sleep quality, which is an important factor in improving their health by administrators and Rizan health program.

Background and Aims: The development and regular use of adhesive systems has started to revolutionize many aspects of restorative and preventive dentistry. The success of adhesive restorations highly depends on correct application of them. Therefore, the present study was conducted with the aim of determining the knowledge of dentists in Rafsanjan city (Iran) in choosing correct dental adhesive systems in 2023.
Materials and Methods: In this cross-sectional descriptive study, all dentists working in Rafsanjan city were included. The data was collected by a valid and reliable electronic questionnaire, which included two parts of demographic information (gender, age, place of work and year of graduation) and the 12 multiple-choice questions aimed to assess respondents' knowledge regarding the selection of dental adhesive materials in combination with self-cure or dual-cure composites, anterior and posterior composite restorations, fiber posts, fissure sealants, primary teeth, anterior composite veneers, ceramic laminates, and non-carious cervical lesions. The scoring of this questionnaire was as follows: 0 to 3 correct answers = Low level of knowledge; 4 to 6 correct answers = Moderate level of knowledge; 7 to 9 correct answers = Good level of knowledge; 10 to 12 correct answers = Very good level of knowledge.  The four answer choices included "etch-and-rinse (three-step)", "etch-and-rinse (two-step)", "self-etch (two-step)", and "self-etch (all-in-one bottle)". Then data were analyzed by parametric tests (ANOVA, t-test, and Pearson). The significant level was considered as P<0.05.
Results: Out of 91 dentists in Rafsanjan, 79 (86.8%) participated in the study, of which 35 (46.3%) were men. The average work experience was 3.49±3.96 years for men and 2.98±3.73 years for women. The average knowledge score was 4.38±2.16 out of 12 (4.29±2.23 in men and 4.45±2.12 in women). The results showed that there was no significant relationship between the knowledge score and the gender, age, work experience, and workplace (P>0.05).
Conclusion: According to the results which indicated the insufficient knowledge of dentists in  choosing correct dental adhesive systems, it is suggested to pay more attention on teaching in this field at the dental schools. For graduate dentists, new and practical information about the choice of adhesive systems should be provided by continuous education programs.

Background and Aims: Over the past two decades, the use of mini-screws in orthodontics has become increasingly common. Various factors such as design, length, diameter, and insertion angle of the miniscrew, as well as the quality and thickness of the patient's bone, would influence the success and stability of miniscrews. This study aimed to investigate the effects of miniscrew shape, cortical and cancellous bone thickness, and insertion/removal torque on the stress distribution in the mandibular bone surrounding the miniscrew.
Materials and Methods: This study was conducted using finite element analysis (FEA). Bone thickness parameters were extracted from the literature, and the mandibular bone along with cylindrical and tapered miniscrew models were simulated using ABAQUS software. By altering the relevant variables, the resulting stress were evaluated.
Results: An increase in both insertion and removal torque led to a corresponding rise in the stress around the miniscrew. Stress variations were more pronounced in tapared miniscrews in response to the changes in bone thickness and torque. The influence of cancellous bone thickness on stress distribution was found to be minimal.
Conclusion: Although, the tapered miniscrews offer greater retention and stability compared to the cylindrical types, their heightened sensitivity to variations in parameters such as bone thickness and torque necessitates cautious application.