1 2251-9890 Babol University of Medical Sciences 358 Restorative Dentistry Effect of diode laser and light-emitting diode (LED) activated bleaching with 35% hydrogen peroxide on microleakage of class-V composite restorations: An in vitro study Abedi Pouya b Mohyadin Zahra c Hosseini Sara d Abbasi Mehdi e b ,Student Research Committee, Rafsanjan University of Medical Sciences, Rafsanjan, Iran. c ,Student Research Committee, Rafsanjan University of Medical Sciences, Rafsanjan, Iran. d ,Student Research Committee, Rafsanjan University of Medical Sciences, Rafsanjan, Iran. e ,Department of Operative Dentistry, School of Dentistry, Rafsanjan University of Medical Sciences, Rafsanjan, Iran. 1 3 2022 11 1 8 14 11 10 2021 08 12 2021 Introduction: Residual oxygen-free radicals of bleaching agents before composite restorations can increase microleakage in enamel and dentin margins, and also various bleaching techniques are being developed using light sources. The present study was conducted to compare the effect of diode laser bleaching and LED activated bleaching on the microleakage of composite restorations. Materials & Methods: This in-vitro study was conducted on 84 extracted human premolars in three groups: In group one, class-V cavities were prepared and the teeth (n=12) were restored with composite ten days after bleaching with 35% hydrogen peroxide with no activator. In groups two and three (n=36 each), the teeth were bleached with a Diode laser activator and LED, respectively. Thereafter, each group was divided into three subgroups (n=12), cavities were prepared and restored with composite three, five, and ten days after bleaching. Digital photographs were used to assess microleakage in the enamel and dentin margins. Data were analyzed using Friedman and Wilcoxon Signed Ranks tests (p<0.05). Results: The lowest amount of microleakage in the enamel margin pertained to the diode laser ten-day subgroup (0.17±0.38) and the diode laser ten-day subgroup in the dentin margin (0.50±1.03). Also, the highest amount of microleakage in the LED group was in the three-day subgroup of the dentin margin (2.78±0.42). Five-day subgroup of diode laser-activated bleaching had a lower amount of microleakage compared to the control group (P=0.042). Conclusion: It may be concluded that diode laser-activated bleaching with 35% hydrogen peroxide has a better effect on reducing microleakage with an interval of five to ten days, compared to the control and LED activated bleaching group.
346 Pedodontics The association between body mass index and gross dental caries in a population of 3- to 5- year-old children attending kindergartens in Rasht, Iran Vejdani Javaneh f Janeshin Atousa g Heidarzadeh Abtin h Mirzazadeh Khadijeh i f ,Dental Sciences Research Center, Department of Pediatric Dentistry, School of Dentistry, Guilan University of Medical Sciences, Rasht, Iran. g ,Dental Sciences Research Center, Department of Pediatric Dentistry, School of Dentistry, Guilan University of Medical Sciences, Rasht, Iran. h ,Department of Community Medicine, Guilan University of Medical Sciences‎,‎Rasht, Iran. i ----------------------- 1 3 2022 11 1 15 20 13 07 2021 27 11 2021 Introduction: Dental caries as the most common childhood disease can cause pain and difficulty eating. The aim of this study was to determine the association between gross dental caries and body mass index (BMI) among children attending kindergartens in Rasht, Iran. Materials & Methods: A descriptive-analytical cross-sectional study was carried out on 402 3- to-5-year-old children who were randomly selected from kindergartens of Rasht, Iran. All dental exams and anthropometric measurements for each child were performed by a trained examiner. The obtained data were analyzed using SPSS 19, and the Z-score index was determined. The Monte Carlo statistical method was applied to compare the relationship between dental caries and BMI. Moreover, the relationship between dental caries and other factors was evaluated using a Chi-square test and P<0.05 was considered significant. Results: In this study, 43.5% of children had dental caries. Based on the results, a significant relationship was observed between dental caries and BMI-for-age, weight-for-age and weight-for-height indices (P=0.02, P=0.004 and P=0.017). The underweight children had higher dental caries experience. Moreover, a significant relationship was found between dental caries and parents’ education level. Conclusion: According to the findings, the underweight children had higher dental caries experience so there may be an association between low BMI and caries experience in children. 353 Restorative Dentistry The effect of dentin pretreatment using silver nanoparticles on shear bond strength of one self-etch and one etch-and-rinse resin cements Mohammadi Farzaneh j Koohpeima Fatemeh k Mokhtari Mohammad Javad l j , School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran. k ,Department of Operative Dentistry, Biomaterial Research Center, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran. l ,Department of Biology, Zarghan Branch, Islamic Azad University, Zarghan, Iran. 1 3 2022 11 1 21 29 20 08 2021 13 12 2021 Introduction: Metal nanoparticles may apply to the cavity walls as acceptable antibacterial agents. The present work was conducted to assess the effect of silver nanoparticles (NPs) on the resin cements Shear Bond Strength (SBS) using one self-etch and one etch and rinse resin cement. Materials & Methods: Sixty intact noncarious extracted, human third molars were selected. All teeth were cut out in the middle of dentin thickness. Resin cement samples were randomly assigned to five groups: (A) Duolink cement without any further surface treatment; (B) Duolink cement with silver NPs (0.5%) dentin surface treatment after acid etching and before the One Step Plus (OSP) adhesive system; (C) Duolink cement with silver NPs (0.5%) dentin surface treatment before acid etching and OSP; (D) Panavia F2.0 cement without any further surface treatment; and (E) Panavia F2.0 cement with silver NPs (0.5%) dentin surface treatment. SBS was assessed by using universal testing machine. Then, human gingival fibroblasts (HGF) cells were treated with tested materials. The biocompatibility of resin cement was evaluated by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-2H-tetrazolium bromide (MTT) assay. Results: The maximum and minimum of the SBS at the presence of silver NPs were observed in group E (15.81±0.91, P-value<0.01) and group B (12.01±0.15, P-value <0.05), respectively. In comparison with the controls, the resin cements incorporated  with 0, 0.2% and 0.5% silver NPs, 20.34%, 22.00% and 22.67% for Panavia F2.0 and 36.84%, 37.34% and 38.17% for Duolink flow - decreased in total cell number, respectively (P-value<0.01). Conclusion: These findings demonstrated that Panavia F2.0 cement with silver NPs dentin surface treatment showed satisfactory result in the SBS compared to Panavia F2.0 cement without any further surface treatment. 351 Oral Medicine Frequency of tobacco use and its relationship with oral soft tissue lesions Saeidi Morteza m Mohammadbeigi Abolfazl n Salehi Fateme o Barakian Yasamin p m ,School of Dentistry, Qom University of Medical Sciences, Qom, Iran. n ,Department of Epidemiology and Biostatistics, School of Health, Qom University of Medical Sciences, Qom, Iran. o ,School of Dentistry, Qom University of Medical Sciences, Qom, Iran. p ,Department of Oral and Maxillofacial Medicine, School of Dentistry, Qom University of Medical Sciences, Qom, Iran. 1 3 2022 11 1 30 37 28 07 2021 29 01 2022 Introduction: Tobacco use plays an important role in the development of oral lesions. The aim of this study was to evaluate the relationship between tobacco use and the incidence of these lesions. Materials & Methods: This cross-sectional study was performed on 399 patients referred to Qom Dental School in four groups of non-tobacco users (n=146), cigarette smokers (n=98), water pipe smokers (hookah) (n=81), and cigarette and water pipe smokers (n=74). Oral lesions, dental caries, halitosis and xerostomia were evaluated with the help of oral examination and the use of a questionnaire. Data were analyzed using the SPSS 24, ANOVA, Chi-square test (P<0.05). Results: The highest prevalence of oral mucosal lesions (98.6%) was noted in group 4 (cigarette and water pipe smokers). Gingivitis, periodontitis, and coated tongue had the highest frequency among all oral mucosal lesions. Xerostomia, halitosis, impaired sense of taste, hairy tongue, coated tongue, nicotinic stomatitis, leukoedema, smoker’s melanosis, and non-keratotic white plaques had significant correlations with tobacco use (P<0.05). Decayed, Missing and Filled Teeth (DMFT) also had a significant correlation with tobacco use (P<0.05). Conclusion:  a wide and varied range of oral mucosal lesions was observed in smokers. Due to its harmful influence on the oral mucosa and awareness of the prevalence of lesions and increase the risk of oral cancer, periodic examinations by specialists are emphasized. 367 General Dentistry An Overview of Dental Assistants' educational Status and Performance in Iran Baghban Yasin Asgari Imaneh ,School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran. ,Dental Materials Research Center, Dental Research Institute, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran 1 3 2022 11 1 38 45 22 11 2021 07 03 2022 Introduction: Demanding qualitative dental services calls for hiring competent staff in dental offices. This study was designed to evaluate dental assistants' educational status and ability to perform tasks. Materials & Methods: In this cross-sectional study, 200 dental assistants working in the offices and clinics of Isfahan, Iran during 2020 were selected using random systematic sampling. The researcher-made evaluation tool with a content validity index of 0.77 was used. Tasks were evaluated by 13 items in 6 sub-scales including communication skills, preparation, radiography, cooperation with dentists, health promotion through prevention and infection control. Moreover, information was requested about the education and training course of the dental assistant. The score of ability was achieved at the range of 0 to 20. The relationship between gender and training course as well as between age and experience level was evaluated with Mann-Whitney test and Spearman correlation. Results: The most frequent major of the study was accounting. The mean total ability score of the dental assistants was 19.1±6.5, ranging from 17.7 to 20. The highest and lowest ability scores were related to the cooperation with dentists and health promotion through prevention, respectively. The mean ability score had a weak relationship with age but had no significant relationship with experience. The mean ability score only in the area of radiography had a significant relationship with the training course and gender (P=0.012). Conclusion: Despite the diversity in the degree and field of study, the ability and task status of the assistants was desirable. In the area of health promotion through prevention, there is a need for training and monitoring its implementation. 359 Community Oral Health Knowledge and therapeutic approach of Iranian dentists toward COVID-19 pandemic Mehrnia Nika Eghbali Zarch Reyhaneh SadeghiPour Maryam ,Depatrment of Periodontics, Dentistry Faculty, Shahed University, Tehran, Iran. ,Depatrment of Periodontics, Dentistry Faculty, Shahed University, Tehran, Iran. ,Department of Community Oral Health, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran. 1 3 2022 11 1 46 55 13 10 2021 13 03 2022 Introduction: Dental services are a hotspot for viral transmission. Dentists must have complete knowledge about the disease and quick access to information to combat this transmission. To prevent COVID-19 viral spreading through dental practices, dentists must be well-versed in disease and infection control measures. As a result, this study aimed to assess the knowledge of Iranian dentists on the Covid-19 pandemic. Materials & Methods: The present study was a questionnaire-based cross-sectional survey. A modified questionnaire of a perused one was prepared, the validity of which was confirmed, and the reliability was accepted by Cronbach’s alpha test (0.86). This questionnaire was completed by133Iranian dentists and included six components: consent to participate in research, demographic information, knowledge, infection control, vaccination, and therapeutic approach. Data were analyzed using Mann-Whitney, Kruskal-Wallis, and Spearman rank correlation coefficients, and  P<0.05 was considered the level of significance. Results: Iranian dentists are shown to have proper knowledge, but only 21.7% of participants received infection control courses; moreover, only 47% of them knew the accurate incubation period of the Virus. Dentists working in Academic clinics took more preventive measures than those working in private clinics (P value=0.023). Conclusion: It is recommended that health care authorities ensure that dentists receive organized information and guidelines. 355 Oral & Maxillofacial Radiology Relationship between maxillary sinus volume and nasal septal deviation concha bullosa and infundibulum size using cone-beam computed tomography (CBCT) Zakariaee Jubari Azadeh Torkzadeh Azadeh ,Department of Oral And Maxillofacial Radiology, School of Dentistry, Isfahan (Khorasgan) Branch, Islamic Azad University, Isfahan, Iran. ,Department of Oral And Maxillofacial Radiology, School of Dentistry, Isfahan (Khorasgan) Branch, Islamic Azad University, Isfahan, Iran. 1 3 2022 11 1 56 63 12 09 2021 29 01 2022 Introduction: The maxillary sinuses are the largest paranasal sinuses adjacent to the teeth. Due to anatomical variations in different people, knowledge of these variations is essential for rhinoplasty and sinusitis. The aim of the present study was to determine the relationship between maxillary sinus volume with nasal septal deviation, concha bullosa and infundibulum size using cone-beam computed tomography (CBCT). Materials & Methods: In this descriptive -analytical study, CBCT images of 135 patients who underwent maxillofacial imaging were evaluated. In order to measure the volume of maxillary sinuses, CBCT images of axial sections were used with a thickness of 2 mm and Digimizer image analysis software. In the coronary section of nasal septum deviation, types of concha bullosa and infundibulum size were determined. Data were analyzed using one-way ANOVA, paired t-test, Pearson correlation test and regression. A value of P<0.05 was considered significant. Results: There was a significant inverse relationship between the mean of volume of the right sinus (p=0.012, r=-0.216) and left sinus (p<0.001, r=-0.303) with the deviation of the nasal septum. A significant inverse relationship was found between the mean volume of right maxillary sinus (p<0.012, r=-0.357) and left maxillary sinus (p=0.006, r=-0.357) with infundibulum size. The mean volume of right and left sinues from coronal view was not significantly different in the presence or absence of concha bullosa.  There was no significant difference between male and female in the mean volume of the right and left sinuses. Conclusion: The present findings suggest that maxillary sinus volume is smaller the deviation in moderate and severe septal deviation cases and that the maxillary and with increasing size of infandibulum, the volume of maxillary sinus was larger. 360 Oral & Maxillofacial Radiology Knowledge and practice regarding dental radiological waste disposal among dental specialists and general dentists in Amol and Babol cities Ahmadpour Shakiba Johari Maryam Naghibi Sistani Mohammad Mehdi ,Student Research Committee, Babol University of Medical Sciences, Babol, Iran. ,Dental Materials Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran. ,Oral Health Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran. 1 3 2022 11 1 64 68 16 10 2021 09 03 2022 Introduction: The aim of this study  was to assess dentists’ knowledge and practice about dental radiological wastes that are dangerous to the environment. Materials &Methods: This was a cross-sectional study  was conducted in 2018-19. All participants completed a two sections’ (knowledge and practice) checklist. Data were analyzed using descriptive statistics, t-test and ANOVA. A value of P<0.05 was considered significant. Results: Totally, 204 (73.5% general dentists and 26.5% specialist) dentists from Amol (35.8%) and Babol (64.2%) participated. The mean age of participants was 39.2 (SD± 10.9) years, and 59.2% of them were female. The average percentage of dentists’ knowledge and practice about radiological waste disposal was 42.55 and 43.12% respectively. Gender, work experience, special or general degree, and city of clinical activity had no significant effect on dentists’ knowledge and practice (P>0.05). Conclusion: More than half of dentists had no correct knowledge and practice on how to dispose radiological wastes. It is necessary to develop specific approaches such as workshops and training classes.