مجله دندانپزشکی دانشگاه علوم پزشکی تهران
سال سی و پنجم شماره 1 (پیاپی 107، بهار 1401)

The aim of this study was to investigate the tooth discoloration caused by cold ceramic compared to MTA Angelus in contact with the washing solutions such as sodium hypochlorite (NaOCl) and normal saline.

50 samples of extracted human maxillary anterior teeth were selected. After preparing the access cavity, they were divided into 4 experimental groups and 1 control group (10 in each group). The access cavities of teeth in groups 2 and 4 were rinsed with 5.25% sodium hypochlorite and those in groups 1 and 3 were rinsed with normal saline. Then, after drying, 3 mm thickness of cold ceramic (groups 1 and 2) and MTA Angelus (groups 3 and 4) were placed in the access cavities of the teeth. After setting of the materials, all specimens were restored with a resin modified glass ionomer. Based on the CIE Lab system, each sample’s total color change (∆E) was obtained before, one, and 90 days after application. Data were statistically analyzed using the Wilcoxon test.

According to the results, there was no statistically significant difference in the average tooth discoloration between the groups filled with cold ceramic and in different time periods (P>0.05). While, in the groups filled with MTA Angelus, the difference in the average tooth discoloration in 90 days after application was significantly higher than one day (P<0.05).

The results of this study showed that compared to MTA Angelus, cold ceramic causes less tooth discoloration over time and therefore, it can be suggested as a more suitable alternative endodontic cement than MTA Angelus.

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.

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.

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

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.

According to the importance of primary stability on dental implant success and osseointegration, we intend to check and compare the stability and crestal bone loss rate between osteotomy technique and conventional implant insertion techniques.

In this study, 26 implants in anterior segment of maxilla in 13 patients were evaluated. The implants were TBR system (Toulouse, France) with 3.5 diameter and 10.5-12 mm length. The implant stability level was recorded immediately after surgery and 3 months later with Ostell mentor. The periapical radiography was taken immediately after surgery, 3 and 6 months to assess crestal bone resorption. Paired t-test and Wilcoxon signed Rank test used for data analysis.

There were no statistically differences between the two treatments techniques in terms of stability (P>0.05). The mean crestal resorption was higher for the osteotomy technique 3 months after implant insertion (P<0.001) but there were no significant differences after 6 months (P=0.678).

Within the limitations of the current study, it can be concluded that the osteotomy it can be considered as a treatment technique in insufficient bone width.

There is a traditional belief that the primary teeth can be replaced by permanent teeth and preserving them is not important. The aim of this study was to evaluate the knowledge and attitude of parents of preschool and elementary school children referring to the Specialty Clinic of Isfahan University of Medical Sciences and Imam Hossein pediatric hospital about the importance of preserving deciduous teeth and related factors.

This descriptive cross-sectional study was performed on 323 parents of preschool and elementary school children referred to the special clinic of Isfahan University of Medical Sciences and Imam Hossein Pediatric hospital. The data collection method was a questionnaire and face-to-face interview. The questionnaire was made, it consisted of 21 multiple-choice questions and descriptive questions. Data were analyzed using descriptive statistics tests and analytical tests such as t-test and Pearson correlation coefficient.

The mean score of knowledge of parents was 37.5 with a standard deviation of 16.9, the mean score of attitude was 55.8 with a standard deviation of 11.1 and the mean score of performance was 41.8 with a standard deviation of 15.6 out of 100. Pearson correlation coefficient showed that there was a direct relationship between knowledge, attitude, and performance scores (P<0.001). Parents' knowledge score was directly related to the mothers' and fathers' ages (P<0.001).

According to the results, parents' awareness of the importance of the preservation of deciduous teeth and related factors is poor, their attitudes are neutral and their performance is poor to moderate. It is suggested to improve treatment facilities available for children in the family and to educate parents about the preservation of deciduous teeth.

The most effective way to maintain and improve oral health is tooth brushing to physically remove dental plaque. In this regard, this study was conducted to compare the efficiency of the usual method of each person in comparison with different methods of brushing to remove dental plaque.

This study was conducted in 2020, as a randomized and open clinical trial with 72 non-dental male and female students of Tehran University of Medical Sciences. In this study, the usual method of tooth brushing with Modified Bass and Scrub Horizontal methods after training was evaluated in two random groups with plaque and gingival indices. Plaque index as a percentage and gingival index as a number (numbers between 0-1 mild inflammation, 1.1-2 moderate inflammation, 2-3 severe inflammation) were reported. The results were analyzed using SPSS25 software and paired t-test and variance equality test.

The efficiency of the usual tooth brushing method in comparison with the two Modified Bass and Scrub Horizontal methods using two indicators of dental plaque and gingival indices was not statistically significant (P>0.05). Each method alone after tooth brushing significantly removed dental plaque (P<0.05).

The results of this study showed that the efficiency of the usual method of tooth brushing compared to trained methods in removing dental plaque and reducing gingivitis in short-term evaluation was not statistically significant.

 Dental caries affects the quality of life of children and parents, oral health and overall health which can interfere with the childrens’ daily activities and growth. The purpose of this study was to investigate the relationship between the severity of dental caries and quality of life in pre-school children.

 This cross-sectional descriptive study was conducted on 145 parents and preschool children aged 2-5 years old referring to Ahvaz dental school and a pediatric dentistry office in Ahvaz city. The convenient sampling method was used and participants were patients referred to the faculty of dentistry and one pediatric dentistry office in Ahvaz. Early Childhood Oral Health Impact Scale (ECOHIS) questionnaire was used to evaluate the oral health related quality of life. The demographic information and dmft index (decayed, missing, and filled teeth) was assessed for children. Statistical analyzes included descriptive statistics, Spearman and Pearson tests.

 The mean age of children was 4.12 ± 1.2 years. 72 children (49.65%) were boys and 73 of children (50.34%) were girls. Based on our results the mean ECOHIS score was 39.69 ± 18.95. There was a significant correlation between decreased quality of life and the lower age of the children (P=0.047), less parental education (P=0.018), more dmft score (P=0.000).

 It can be concluded that severity of dental caries is effective on children's quality of life. The quality of life of children decreases with the increase in the dmft, lower socio-economic status of parents, and higher age of parents.

 Atypical facial pain (AFP) is a chronic disease associated with local pain in the craniofacial area. A wide range of treatments including drug therapy, psychiatric methods and open surgery are used for its treatment. Opiorphin is a pentapeptide that can block pain and also has proven antidepressant effects. The aim of this study was conducted to investigate the opiorphin concentration in AFP patients and to compare it with healthy people.

 This study was performed on 30 AFP patients and 40 healthy individuals. Unstimulated saliva was collected from both groups by spitting method. HAD-A (Hamilton Anxiety Test) and HAD-D (Hamilton Depression Test) questionnaires were completed for all patients and controls. Psychological interview with the patients and psychological analysis were performed to determine anxiety and depression scores. Data analysis was done using SPSS (ver.24) statistical software

 The subjects of two groups were homogeneous in terms of age and sex. The mean salivary opiorphin concentrations in the case and control groups were 1.8050±0.2923 and 1.8032±0.3682 ng/ml, respectively. According to the results of t-Test, no significant difference was observed in the mean opiorphin concentration between the AFP group and control group (P=1.000). According to the Pearson's test, no significant relationship was found between the opiorphin levels and the age, sex, and anxiety or depression score in the patient and control groups (P>0.05). Also, there was no remarkable correlation between initial VAS, duration of pain and previous treatments with opiorphin levels in the AFP patients (P>0.05). No significant correlation was found between the opiorphin concentration and menopausal period in the case and control women (P>0.05).

 The results showed that most AFP patients had some degree of anxiety and depression. However, salivary opiorphin concentration did not significantly increase in the AFP patients.

 By using the image processing capability in Cone-Beam Computed Tomography (CBCT), obtained information can be improved. The aim of the present study was to investigate the effect of sharpen image processing filter in determining the external resorption of the root apical region in single-rooted teeth due to the proximity of the impacted tooth using CBCT.

 In this laboratory study, the lateral surfaces of the apical region of the root of 40 healthy extracted teeth were artificially cut by bur and the teeth were randomly divided into four groups: control, low, moderate, and high resorption. After preparing CBCT of the teeth, the samples were then processed with and without an image sharpening processing filter and examined by two observers. The results of this study were analyzed by SPSS22 and Medcalc Statistical Software version 14. The significance level was considered P≤0.05 for all the statistical tests.

 Specificity (100%) and sensitivity (66%>) were either complete or very high for both modes without and with the sharpen filter. The overall accuracy (0.83>) was high in both cases and no significant difference was observed between the two overall accuracies (P>0.05). Statistical analysis of both image observations by two observers showed that the overall sensitivity and accuracy in the medium and high resorption groups was much higher than the low resorption group, but the specificity in all groups was 100%.

 The results showed that the images with a sharpening filter did not increase the detection power compared to the unfiltered images. However, as no loss of accuracy was observed with this filter, it could be used as a processing filter.

 With the growth of elderly population, attention to their oral health status has become increasingly important. Most of the available studies have been conducted among dependent elders who usually have different oral health statuses and needs. Therefore, the aim of this study was to determine the oral health status of independent elderly attending municipal public centers and parks in Isfahan in 2020.

 This is a descriptive-analytical cross-sectional study conducted among 195 elderly people attending Isfahan municipal centers in 2020. The oral health status and the oral health related quality of life (QOL) of elderly were evaluated using Geriatric Oral Health Assessment Index (GOHAI) and clinical examinations. The obtained data were analyzed using descriptive statistics (mean and standard deviation), correlation, independent T-test, Chi-squared and ANOVA using SPSS22 (α=0.05).

 69% of the participants (n=133) were male and the mean age was 68.9± 3.5. Almost 20% of elderly (n=39) did not have any of their natural teeth. 63% (n=123) suffered from at least two chronic diseases and 38.5% (n=75) had a functional occlusion. The mean score of quality of life (QOL) of elderly and their DMFT was 51.7±6.4 and 20.5±6.3, respectively. A significant and negative relationship was found between the DMFT and GOHAI (P<0.001, r=-0.36). QOL scores were significantly higher in participants with dentures than those without dentures (P<0.001). There was a significant relationship between the frequency of brushing and the mean of DMFT (P<0.001). In people who did not brush, the DMFT score was higher than those who brushed at least once a day or even sometimes a week.

 The results indicated that the oral health status of elderly was weak and it would reflect the need for more attention to taking more measures to both prevent the oral problems and to promote oral health.

 The aim of this study was development and validation of a questionnaire measuring the pseudo-scientific unsupported of Iranians’ belief regarding oral health.

 A list of 169 pseudo-scientific and invalid Iranian beliefs about oral health that was collected in the previous phase of the study were sent to a purposive sample of 13 professors at Mashhad dental school which resulted in extracting 34 beliefs being considered more common among Iranians. A list of 21 pseudo-scientific beliefs was obtained for preparing the questionnaire after receiving the sample opinions of 21 professors of Mashhad dental school about the invalidity and pseudoscientific propositions and their written revision. Finally, the questionnaire was completed by 44 participants to analyze the ease and clarity and to calculate Cronbach's alpha and Kuder Richardson measure as a homogeneity reliability index. It was completed in a group of 15 participants with a time interval of one month for test-retest analysis and consistency reliability evaluation.

 A questionnaire consisting of 21 beliefs was developed using four-point, three-point, or two-point Likert scales. The standardized Cronbach's alpha score and Kuder Richardson's measure score were 0.641 and 0.514, respectively, which indicated the moderate to good reliability of the homogeneity. The Interclass Correlation Coefficient (ICC) was calculated as 0.863, representing very good reliability of consistency of the questionnaire. Furthermore, the kappa coefficient of each of the 21 statements had a significant difference with zero (P<0.05) ranging between 0.605 and 1.

 The result of the present study is a questionnaire measuring the level of Iranians’ belief in unsupported and invalid statements about oral health. Using this questionnaire would be helpful for dentists and oral health professionals to promote knowledge of Iranians about oral health.

 Activity-based costing enumerate every input consumed in treatment. The Covid-19 pandemic changed the dental treatment protocols and the ordinary circumstances of patients. The aim of this study was to calculate and compare the costs of three common dental services in Iran from the viewpoint of the providers and recipients of the services before the Covid-19 pandemic (2019) and during the pandemic (2021).

 Direct medical and non-medical costs were considered from the service provider's perspective. Direct medical costs, indirect costs, direct non-medical costs, and intangible costs were considered from the recipient's perspective. To calculate the equivalent costs, the base year was considered 2021, and the costs of 2019 were calculated with a discount rate of 16%.

 From the service provider's perspective before the pandemic, the cost of dental amalgam restoration was 2,851,235 Rials, root canal treatment was 6,351,580 Rials, and tooth extraction was 1,887,295 Rials. The cost of these services in 2021 was 5,562,150 Rials, 8,070,591 Rials, and 4,865,563 Rials, respectively. From the recipient's perspective, before the pandemic, the cost of tooth restoration was 715,466 Rials, root canal treatment was 2,883,001 Rials, and tooth extraction was 3,267,359 Rials. The cost of the mentioned services in the year 2021 was 1,212,528 Rials, 3,971,640, and 3,680,880 Rials, respectively.

 The Covid-19 pandemic has had an effect on increasing the cost of dental services from both the service provider and recipient perspective, but economic volatility has a vital role in increasing the estimated costs in the country. Probably, a part of the increase in costs was due to the role of brokers in providing dental materials and equipment.

Cathepsin-D is a well-known protease that promotes invasion in tumoral lesions. Considering the cystic neoplasm nature of odontogenic keratocyst (OKC), the aim of this study was to compare the expression of cathepsin-D in this lesion with the unicystic ameloblastoma (UA) and orthokeratinized odontogenic cyst (OOC) for better understanding of its behavior.

In this descriptive-analytical study, we used paraffin blocks available in the archives of oral and maxillofacial pathology department of dental school (8 unicystic ameloblastoma (UA), 8 odontogenic keratocyst (OKC) and 8 orthokeratinized odontogenic cysts (OOC)) which they were stained immunohistochemically with cathepsin-D. Then, the samples were observed simultaneously by two oral pathologists for detection the intensity and pattern of epithelial and stromal cells staining. Data were analyzed by SPSS20 and Kruskal-Wallis, Mann-Whitney and Chi-square test (P<0.05).

The staining intensity of the epithelial cells of UA group was significantly more than OOC and OKC (P=0.02). The staining intensity of the stromal cells of UA was more than the other two groups, although this difference was not statistically significant (P=0.32). The pattern of cell staining in epithelium and stroma did not show any significant difference between the three groups in this study (P=0.15, 0.22).

The results of this study regarding the intensity expression of cathepsin-D in these three odontogenic lesions could be considered as a probable evidence for the new odontogenic lesions classification (WHO2017) in terms of reintroducing OKC as an odontogenic cyst. If this idea is rejected, it seems that cathepsin-D expression is not associated with the invasive behavior of this cyst, and further investigation of other markers in the epithelium and stroma simultaneously is suggested for a better understanding of its biological nature.

Selecting the appropriate education evaluation method and the effects of this choice according to different fields of medical sciences, is one of the current priorities of medical education. Therefore, the aim of this study was to design a checklist for evaluating the practical skills of dental students and to get compared with the global ranking method.

A checklist was developed for the assessment of clinical skills of the practical pediatric course according to an action research method. 32 students were evaluated by the checklist method and 32 students were evaluated by the conventional global rating method (sampling was based on available sample).  Faculty staff and students’ satisfaction regarding the two methods were reported by a 6-scaled measure and statistically analyzed by Wilcoxon Signed Ranks test. The students' scores by the two methods were subjected to paired t test for comparison.

The students were more satisfied with the checklist method (P=0.003). The faculty staff considered a greater ability of the checklist method to differentiate between the students (P=0.03). However, in terms of ease of use and suitability, most faculty staff preferred the traditional method (P=0.02). In other cases, there were no significant differences in the views of students and faculty staff towards the two methods.

In the present study, both Checklist and global rating methods were valuable for evaluation, although due to the greater satisfaction of students and faculty staff with the developed checklist method, the possibility of identifying the weak points leading to decreased scores and better assessment of capabilities, this checklist can be used for evaluation instead.

Different factors play a role in causing tooth decay. Modern dentistry is looking for a way to prevent tooth decay and suggests different ways to increase remineralization. The aim of this study was to evaluate the effect of nanohydroxyapatite toothpaste and mouthwash on remineralization of primary enamel lesions and obstruction of tubules.

In this study, 90 human extracted central teeth were used. Artificial decay was induced by placing the specimens for 72 hrs in a demineralization solution in an incubator at 37 °C. Hardness of the specimens was determined by a microhardness test before any surface treatment. The specimens were then divided randomly into 6 groups of 15. For 1-6 groups, the specimens were subjected to a pH cycling for 14 days, which included 3 hrs of demineralization and 21 hrs of remineralization. At the same time, 1-3 groups were in contact with diluted toothpaste in a ratio of 1:3 with deionized water at a rate of 5 ml twice a day for two min. Eac specimen of 4-6 groups was exposed to 5 ml of three types of mouthwashes for one min. Then, the specimens were cut in the buccolingual direction in order to simultaneously evaluate the dentinal tubules and Vickers microhardness test was performed again and the before and after microhardness values were compared. Then, the percentage of deposition on the surface and tubule obstruction were analyzed using SEM (Scanning electron microscope) (P=0.006). Data were analyzed using SPSS24 software bu the descriptive statistics, ANOVA analysis of variance, and multiple Tukey comparisons.

The results of analysis of variance test showed that there was a statistically significant difference in the microhardness changes between study groups (P=0.006). Also, in-group analysis of microhardness changes, there was a significant difference (P<0.0001). Besides, only in the group containing 0.5% nanohydroxyapatite toothpaste, more than 50% tubule deposition and obstraction was observed (P<0.05).

According to the present study, nanohydroxyapatite can be one of the treatment strategies to repair incipient lesions of teeth and the addition of nanohydroxyapatite, preferably to toothpaste, increases the dental microhardness.

Achieving non-invasive methods for the proper detection of secondary caries adjacent to dental restorations has a great importance. As alterations in horizontal and vertical angles of X-ray beam would affect the detection of dental caries on radiographs, this study was designed to evaluate the effect of changing the horizontal angle of X- ray on detection of dental caries adjacent to class II amalgam restorations in posterior teeth on periapical radiographs.

In this in vitro study, artificial carious lesions were prepared in axial walls of the amalgam restoration cavities in interproximal surfaces of 27 human extracted premolar teeth. Periapical radiographies with different horizontal X- ray angles were obtained, observed, and rated by 5 maxillofacial radiologists for detection of carious lesions. For each observer, the sensitivity, specificity, accuracy, PPV, and NPV of radiographs in the individual horizontal angles were calculated and compared by nonparametric Kruskal Wallis test. Interobserver agreement was assessed by fleiss’ kappa coefficient.

The highest accuracy of periapical radiographs for the detection of secondary caries of mesial dental surfaces was in 5-degree of mesial and distal X- ray angle (86.66%) and for the distal dental surfaces was allocated to 10-degree of distal X- ray angle (85.90%). Also, there was a significant difference in the accuracy between different horizontal angles (mesial and distal 0, 5, 10, 15-degree) (P=0.01). The higher agreement between observers in detecting mesial surface caries was in 10-degree of distal angle (0.86) and in detecting distal caries was in 5-degree of distal angle (0.89).

In the case of doubt in the existence of recurrent caries in the interproximal tooth surface, if the carious lesion is not visible on standard radiographic image with direct angle of X- ray, A 5- 10 degree of x- ray horizontal angle can improve the detection of secondary caries under amalgam restorations in interproximal dental surfaces.

For dental students, communication skills are essential to effectively transfer the necessary information to the patient and meet the patient’s needs and expectations. Therefore, this study was conducted to determine the patient communication skills of dental students at Islamic Azad university of Isfahan in 2021.

In the present cross-sectional analytical study, an online standardized questionnaire DCCC (Dental consultation communication checklist) was provided to all clinical dental students applying a census sampling method. In total, from 248 clinical dental students, 230 students participated in the study (response rate=92.7%). The questionnaire included five dimensions of introduction, medical history, clinical examination, closure and patient. In order to determine the patient communication skills, its dimensions, and the association between patient communication skills and students’ demographic characteristics, friedman test, analysis of variance, independent t-test and a linear regression model were used for statistical analysis.

The mean score of total communication skills of the students (117.16±15.6) was above average which was obtained from the maximum score of 155. There was a significant difference between the dimensions of communication skills (P<0.001). The highest scores were assigned to the clinical examination, patient, medical history, introduction and closure, respectively. No significant relationship existed between the score of students' communication skills with gender (P=0.08), age (P=0.17), marital status (P=0.19), and educational background in psychology (P=0.07). No significant relationship revealed between the total score of communication skills (P=0.92) and its dimensions (introduction P=0.79, medical history P=0.90, clinical examination P=0.77, closure P=0.35, and patient P=0.85) with the students’ academic year.

The total score of dental students’ communication skills and all its dimensions was above average. However, students reported poorer performance in dimensions of introduction and closure than the other dimensions. Therefore, it is recommended to design and implement educational interventions specially to improve the dimensions of introduction and closure.

The 2019 coronavirus pandemic has resulted in a lot of pressure on health systems around the world. The risk of transmission of infection in dentistry is significantly high. The aim of this study was to evaluate Covid-19 protection knowledge and practice of dentists in Isfahan in clinical environment.

In this study which was performed in April 2021 by available sampling method, an online questionnaire was used as a data collection tool. Questions included demographic characteristics, knowledge of proper protective protocols, protection protocols taken against Covid-19, and the prevalence of Covid-19 infection. Descriptive and analytical analyzes were performed using SPSS26 software including frequency distribution tables, graphs, independent t-test, and Pearson and Spearman correlation coefficients.

310 questionnaires were collected with complete answers. 87.4% of dentists had moderate and high knowledge of proper protective protocols against Covid-19. The mean knowledge score had no significant relationship with the demographic characteristics of age (P=0.59), gender (P=0.31 and r=0.05), work experience (P=0.16 and r=0.07) and degree (0.33=P). In the pandemic period, 87% of dentists treated dental emergencies and 40% delayed the dental treatment for patients with high risk of Covid-19. Dentists used personal protective equipment correctly. Among all the included dentists, 75% used high protection masks, 75% used face shields, 67% used hats, and 60% used sterile gowns in all of their treatment activities. The clinical environment was equipped well to prevent spreading of Covid-19. The results showed that 55.8% of the participants had one or more similar signs/symptoms of Covid-19 and 9% had a positive SARS-CoV-2 test during the last months.

The majorities of dentists had enough knowledge of proper protective protocols against Covid-19 and efficiently used all protections while performing dental procedures.

Recently, the addition of nanoparticles into the restorative materials and tooth preparation by laser for improving the bond strength have been concidered by researchers. The aim of this study was to investigate the shear bond strength of the bioactive glass ionomer containing titanium particles and a conventional glass ionomer with two surface treatments by Er-YAG laser and conventional methods.

In this in-vitro study, 64 sound extracted premolars were collected. For conventional method, the specimens were prepared in such a way that dentin surfaces with a depth of 0.5 millimeter created at distance of 2 mm from the joint of CEJ at the root or crown.  In the laser group, after preparing the teeth, the surface area was prepared by Er-YAG laser. Then, in the middle part of the buccal surface, a cylindrical mold with dimensions of 3.5 mm in diameter and 4 mm in height was placed and for each group was filled with its own glass ionomers. The  specimens  were divided into 8 groups by simple random sampling (n=8): A (laser, conventional glass ionomer, coronal dentin)/ B (laser, glass ionomer containing titanium nanoparticle, coronal dentin)/C (conventional, conventional glass ionomer, coronal dentin)/ D (conventional, glass ionomer containing titanium nanoparticle, coronal dentin)/ E (laser, conventional glass ionomer, root dentin)/ F (laser, glass ionomer containing titanium nanoparticle, root dentin)/ G (conventional, conventional glass ionomer, root dentin)/ H (conventional, glass ionomer containing titanium nanoparticle, coronal dentin). Finally, the shear bong strength by a universal testing machine was measured at a cross-head speed of 1 mm/min. For data analysis, Two-way ANOVA test was used to evaluate the effect of each variable and their interaction on the shear bond strength and Tukey test was used to compare the two groups.

There was significant difference only between groups B with C (P=0.002), E (P=0.007), G (P=0.001) and H (P=0.01). The highest bond strength was found for group B (laser, glass ionomer containing titanium nanoparticle, coronal dentin) and the lowest bond strength for group G (conventional, conventional glass ionomer, root dentin).

All three factors of Er-YAG laser, glass ionomer containing titanium nanoparticle and coronal dentin had a positive effect on the improvement of the bond strength.

Oral health is a necessity and part of general health and its importance in childhood is more than ever. The aim of this study was to investigate the knowledge, attitude, and practice of parents in Delfan city-Iran about oral health of their 6-12-year-old children in 2021.

The present study was a descriptive-analytical study that was performed on 365 parents of 6-12-year-old children in Delfan city. Convenience sampling was used. The questionnaires included four sections: demographic information, knowledge, attitude and practice about oral health. Data were entered in SPSS23. Independent t-test, analysis of variance and Pearson correlation were used to analyze the data. Significance level was considered 0.05.

The mean age of the subjects was 36.5±7.1. 201 of parents were mothers. Parents' knowledge and attitude were good and their performance was fair. There was a statistically significant relationship between all three variables of knowledge, attitude, and practice (P<0.00). Also, there was a statistically significant relationship between the knowledge and education (P<0.00), mother job (P<0.04), father job (P<0.00), and economic status (P<0.00). There was a statistically significant relationship between the attitude with education (P<0.00), mother job (P<0.04), father job (P<0.01), and economic status (P<0.01), There was a statistically significant relationship between practice and education (P<0.00), mother job (P<0.01), father job (P<0.00), and economic status (P<0.00) of parents.

The results of this study showed that there was a significant relationship between the knowledge, attitude, and practice with education level, job and economic status. Therefore, oral health education for parents with low educational and economic level should be highly considered.

The objective of this study was to evaluate the knowledge, attitude, and practice of ergonomics during dental treatment among students of Urmia university of medical sciences in 2020.

In this descriptive-analytical study, self-administered questionnaires were given to 78 dental students of Urmia University in 2020 and the knowledge, attitude, and practice of every participant were evaluated. Demographic data including sex, age, and University grade were recorded as well. Data were analyzed by SPSS software24 with One Way ANOVA and t-test and the significance level of P<0.05.

78 students (44 males and 34 female) by Mean Age 23.9±2.12 were included in the study. The difference between the attitudes of different age groups was significant (P=0.006). The age group of 20 to 24 years had a more positive attitude than other age groups. However, the results of this study did not show a significant r elationship between the participants' knowledge and practice with their age (P>0.05).

According to this study, the knowledge, attitude and practice of Urmia dental students were in the desired range. 20-24 year students had significantly higher attitude in comparison to others. Therefore, more endeavors should be taken to improve these parameters in ergonomics.

Considering the preventive and therapeutic effects of resin infiltration (RI) and the unknown effect of bleaching on the enamel treated with this method, this in-vitro study aimed to assess the effect of bleaching on color stability of enamel lesions treated with RI.

In this in-vitro, experimental study, enamel-dentin samples measuring 5×5×3 mm were prepared on the buccal and lingual surfaces of 30 extracted humans third molars with no caries, cracks or enamel defects by a microtome. The specimens were divided into three groups of 10 specimens: 1) sound enamel (control), 2) demineralized enamel, 3) demineralized enamel plus RI. White spot lesions were artificially created by immersing the samples in hydroxyethyl cellulose demineralizing gel with a pH of 4.5 for 4 days. Next, Icon RI was applied on the samples in group 3. The baseline color of the specimens was measured using a spectrophotometer. Then, 35% hydrogen peroxide was applied on the specimens in three cycles and time interval of 10 min. After the end of the last cycle, the samples were completely washed for 1 min and then, underwent colorimetry again. Data were analyzed using one-way ANOVA.

The results of this study showed that the highest level of color change (ΔE) in the demineralized group was 6.3±2.003, while the least amount of ΔE in the enamel lesion group treated with resin infiltration was 3.54±0.98 and in the control group ΔE was 4.13±1.14. Therefore, there was a significant difference between demineralized and treated by infiltratant groups (P=0.005). However, there was no significant difference between control group and treated with resin infiltration group (P=0.54).

Bleaching induced a less change in the color of the enamel lesions treated by resin infiltration compared with that of the demineralized teeth.

Finishing and polishing of composites is a critical step influencing the clinical service of restorations. The aim of this article was to evaluate and compare the effect of two liquid polishes on the polish retention of two nanocomposites.

Eighty standardized disk-shaped specimens (4×2 mm) were prepared from two nanocomposites (n=40), including one nano-filled composite (Filtek Z350 XT-3M ESPE, USA) and one nano-hybrid composite (Aelite Aesthetic Enamel-Bisco, Inc. Schaumburg, USA). The specimens were randomly divided into 4 subgroups (n=10) based on the method of finishing (F) and polishing (P) procedures: M: as control, polymerized under Mylar strip; S: finish and polish with a sequence of Sof-Lex discs (3M ESPE, USA); SP: finish and polish with Sof-Lex discs and use of Permaseal liquid polish (Ultradent products, Inc. USA); SB: finish and polish with Sof-Lex discs and use of Biscover liquid polish (Bisco, Inc. Schaumburg, USA). The specimens were undergone pH cycling and brushing machine and then, the average surface roughness (Ra) and average profile changes along the desired area (Rz) of the specimens were determined with profilometer instrument. Two-way and one-way analysis of variance (ANOVA) was used to compare the mean of surface roughness. Then, Tukey test was used to identify the groups responsible for the difference and t-test was used to compare the mean of surface roughness.

The type of composite and the method of polishing procedure had no effect on the mean Ra (P=0.733) but it had significant effect on Rz1 factor (P=0.025).

Using liquid polish after polishing discs had no effect on the polish retention of nanocomposites.

 Malocclusion in orthodontics is one of the dental and jaw abnormalities that can cause psychosocial and social problems. Personality traits, body image, and self-concept are different in orthodontic applicants due to the different effects of malocclusions on appearance and psychological well-being. The aim of this study was to investigate the personality traits, body image, and self-concept in patients seeking orthodontic treatment in Tabriz-Iran in 1400.

 The statistical population of the study included all patients requesting orthodontic treatment whom were referred to one of the orthodontic clinics in Tabriz during 1399-1400. This study was performed on 149 patients seeking orthodontic treatment (127 females and 22 males) by Convenience Sampling method. Neo personality traits, the Body Image Concern, and Marsh body self-concept questionnaires were used. SPSS software was used for data analysis.

 According to the results, neuroticism, agreement, conscience, extraversion and openness to experience were high in orthodontic patients (P<0.05). The average dissatisfaction with body image was high (P<0.05). Also, the body outside self-concept was low and the self-esteem was high (P<0.05).

 Personality factors, body image, and self-concept are three effective psychological characteristics in patients seeking orthodontic treatment. Therefore, the request for orthodontic treatment is largely due to psychological factors such as differences in personality traits, body image, and self-concept.