مجله تحقیق در علوم دندانپزشکی
سال بیست و دوم شماره 1 (پیاپی 83، بهار 1404)

Calcium hydroxide (CH) is one of the most common intracanal medicaments. The residual calcium hydroxide along the root canal wall increases or decreases the sealing quality of the root canal filling. This study aimed to compare the leakage of different sealers in presence of calcium hydroxide.

In this in-vitro study, the 90 three-rooted and canal human mandibular molar teeth with mature apex selected with a curvature of less than 10 degrees were cleaned and shaped and divided into two groups (n=45). The first group was not medicated and the second group was medicated with calcium hydroxide. After 2 weeks, calcium hydroxide was removed from the root canal. Then the root canals were sealed using 3 different types of sealer (MTA Fillapex, AH26 and Endoseal MTA) with standard gutta percha and lateral condensation technique. The samples were immersed in India ink. After 4 weeks, the samples were demineralized and dehydrated. Apical leakage was measured by a microscope with a magnification of 0.1 mm. Data were analyzed using SPSS software and two-way ANOVA and Tukey HSD test

The lowest levels of leakage, both in the presence and absence of calcium hydroxide, were observed in the AH26, Endoseal MTA, and MTA Fillapex sealers, respectively. The leakage level in each sealer was lower in the absence of calcium hydroxide compared to its presence. Based on the two-way ANOVA test, the type of sealer (P<0.001), the use or non-use of calcium hydroxide (P<0.001), and the interaction between the type of sealer and the use or non-use of calcium hydroxide (P<0.001) had a significant impact on leakage. The mean leakage of the AH26 sealer was significantly lower than that of the Endoseal MTA and MTA Fillapex sealers (P<0.001). The mean leakage of the Endoseal MTA sealer was significantly lower than that of the MTA Fillapex sealer (P<0.001).

All sealers had apical leakage and filling with them with and without the calcium hydroxide did not completely prevent dye leakage. The leakage rate of AH26 was lower than the other two sealers and the leakage rate of MTA Endosael was lower than MTA Fillapex. In the absence of calcium hydroxide, the amount of leakage is less.

Streptococcus mutans is a key contributor to dental caries. Herbal compounds are increasingly explored as alternatives to chemical drugs with fewer side effects. This study compared the effect of ethanolic black seed extract and chlorhexidine on S. mutans under laboratory conditions.

Streptococcus mutans (PTCC1687) was obtained and the ethanolic black seed extract prepared by soaking in ethanol. The disk diffusion method on Mueller-Hinton agar was used to evaluate antibacterial activity at extract concentrations ranging from 0.09% to 50%. The diameter of inhibition zones was measured, and MIC/MBC values were determined using Microdilution and Macrodilution methods. Each experiment was repeated three times. Statistical analysis was performed using the T-test in SPSS software version 25.

The mean inhibition zone for the black seed extract was 16 mm, whereas chlorhexidine produced a 20 mm zone. For black seed extract, the MIC was 12.5 mg/ml and the MBC was 25 mg/ml. For chlorhexidine, these values were 0.6 mg/ml (MIC) and 1.2 mg/ml (MBC). The T-test showed a significant difference (P < 0.05) in inhibition zone diameters between the black seed extract and chlorhexidine.

Ethanolic black seed extract displayed a positive inhibitory effect on S. mutans but was less effective than chlorhexidine. Further research may focus on optimizing black seed extract’s antimicrobial properties to provide a viable natural alternative in oral health applications.

Assessment is an important aspect of education. This study was conducted with the aim of evaluating the educational program of department of pedodontics from the perspective of Tehran Islamic Azad University of Medical Sciences undergraduate students based on the CIPP evaluation model.

In this descriptive-analytical study, the DREEM questionnaire consists of  50 questions in 5 areas of student perception of learning, professors, educational atmosphere, academic ability, and social conditions ,and the product questionnaire includes three checklists made by the researcher based on the pediatric dentistry program according to the curriculum of the Ministry of Health, which the validity and reliability had been confirmed, were distributed by census method among 209 students who had passed 1st, 2nd and 3rd practical pediatric dentistry . Kolmogorov-Smirnov test was used to determine the normality and the data were analyzed by One-way ANOVA, Tukey HSD and Regression tests and values less than 0.05 were considered significant.

In product context, the response "I can do it alone" was 56.34%, 59.73%, and 55.62% for 1st, 2nd and 3rd practical pediatric dentistry respectively. The average score of the DREEM questionnaire was 113.79 out of 200 total scores (56.89%). The average range of students' perception of their social conditions based on academic semester had a significant difference (p=0.004). The average perception of students about their social conditions in the 10th semester students was significantly higher than the 11th semester (p=0.003). Age, gender and entrance type did not have a significant effect on the determination of students' perceptions in different areas and the overall score of the DREEM questionnaire (p>0.05), however, gender had a significant inverse relationship with students' perception of their social conditions (standardized beta = 0.136, P = 0.079) (P value > 0.1).

The findings of the present study indicate that the students' perception of the Pediatric Dentistry Department of Tehran Islamic Azad University of Medical Sciences was in a favorable condition in the context and product areas, and it seems that this group has been successful in achieving its educational goals.

Post-operative infection is one of the most common complications following mandibular fractures. This study aims to assess the prevalence of post-surgical infection between patients with and without opioid abuse.

In this prospective cohort study, the prevalence of post-operation infection was documented in patients who had a mandibular fracture and underwent open reduction with rigid fixation (ORIF). In group1, patients with no opioid abuse, and in group 2, patients with opioid abuse were placed. Age, gender, the time between trauma and operation, plaque index, and white blood cell (WBC) counts of the patients were registered. Fisher's exact test was applied to compare the prevalence of infection between groups.

A total of 150 patients were included in the study, 20 of whom had a history of opioid abuse. In the first group, eight (6.2%) out of 130 patients had signs and symptoms of infection after the operation, and in the second group, 11 people (55%) out of 20 patients experienced infection. There was a statistically significant difference between the two groups regarding the prevalence of postoperative infection (p<0.001).

It seems that opioid abuse along with smoking and poor oral hygiene can lead to postoperative infection in patients with mandibular fracture.

Examining the level of satisfaction of service recipients from any educational system can reveal the strengths and weaknesses and improve each system. The objective of this study was to investigate the satisfaction of dental students at Islamic Azad University of Medical Sciences, Tehran branch, with the clinical departments in the academic year 1401-1402.

A total of 150 fifth- and sixth-year dental students participated in this descriptive cross-sectional study. They were given a 16-question satisfaction questionnaire to assess their satisfaction with 10 clinical departments. The questionnaire focused on professors, nurses, facilities and equipment, and the students' self-confidence in their learning. The average satisfaction level of students with each department was measured. One-way ANOVA was used to compare satisfaction levels between different departments, while multiple linear regression was used to evaluate the relationship between satisfaction and factors like age, gender, academic semester, and overall grade point average.

The highest average satisfaction level was found in the oral&maxillofacial diseases department, while the removable prosthesis department had the lowest satisfaction level. However, there was no significant difference in satisfaction levels between different departments (p=0.6). Additionally, there was no significant difference in satisfaction levels across the four investigated areas. None of the investigated variables showed a significant relationship with satisfaction

Overall, the satisfaction level with the clinical departments of the Faculty of Dentistry was average. There were no significant differences in satisfaction levels between different departments or in the four investigated areas.

Dentists are one of the vulnerable groups in relation to hearing loss due to long-term contact with noise caused by high speed and low speed hand pieces and other sound generating devices in dental units. The aim of this study was to Compare the noise pollution caused by NSK, Goldent, Coxo and Bien Air highspeed and Low speed handpieces in dental work environment.

In this descriptive study Sound pressure level was measured using Benetech sound meter (sound meter level) model 1356GM in a sound isolation room using ISO 3744 standard. High and low speed hand pieces are each connected to the microunit at a distance of 1 meter from the sound meter, and after reaching the highest speed, its sound pressure was recorded for 1 minute. Two-way ANOVA and Tamhan and Tukey statistical tests were used for statistical analysis.

the average sound level of the BienAir high speed and low speed handpieces respectively was 57 -57.7dB, the Coxo was 61-66.1 dB, the Goldent was 63-64 dB, and the NSK was 62-65dB . the highest average sound level is associated with goldent highspeed hand pieces and Coxo low speed hand pieces.

The sound level created by high and low speed hand pieces is lower than the threshold of international standards and very close to the hearing loss limit (80 dB) so long-term exposure may have adverse effects on health

This study investigated the correlation between the developmental stages of the third molar and chronological age in Kashan city. Determining people's age is particularly important in forensic dentistry. The best way to estimate people's age is to use radiographs and the best radiographs are dental graphs. Meanwhile, the best method is to use the developmental stage and the most favorable tooth for this task is the third molar. Due to the fact that developmental stages are dependent on inheritance and environment, it is necessary to examine each population specifically.

It was descriptive and cross-sectional study. By referring to the radiology centers of Kashan city, the archives of the last year of panoramic radiographs that met the entry and exit criteria were taken. The chronological age of the patients was extracted from their files. The calcification of the third molar tooth was ranked based on the approach suggested by Demirjian et al. Then the linear correlation coefficient between Demirjian’s score and chronological age was calculated.

Finally, 464 panoramic radiographs were examined. The age range of the patients was from 9 to 23 years. Among them, 257 were women (51.4%) and the rest were men. In general, the average age of adolescent clients based on Demirjian’s developmental criteria for the third molar teeth was 9.33 years on average in category A and 20.83 years in category H. It was also observed that with the increase in the developmental stages of Demirjian, the developmental age has increased.

This study showed that there is a significant relationship between the calcification stage of the third molar and chronological age.

Assessing clinical capability is one of the most important tasks of professors in the health system. Clinical dental evaluation has not been done systematically yet so we decided to evaluate clinical skills of dental students in field of restorative treatments at pediatric preclinic & clinic stages in dental school of Tehran Azad University of medical science in academic year 2020-2021 By DOPS.

This cross-sectional study was performed on 52 clinical & 67 preclinical students. Necessary items for evaluation was classified in a checklist of 14 items which included 2 pre-restoration related items (diagnosis and preparation of materials and equipment), 11 restoration related items (injection, cavity preparation, cavity filling and communication with patient and parents) and 1 post-restoration item (giving necessary advice to the parents). It was set in a range of three options including good, medium and poor (score 0 to 2). Finally, a less than 14 clinical skill score was considered as inappropriate skill. Necessary items to assess clinical skills in the class II restoration of deciduous molars on denticles was classified in a checklist of 14 items which included principles of correct class II cavity preparation, good behavior and students speed of action. It was set in a range of three options including good, medium and poor (score 0 to 2). Finally, a less than 14 clinical skill score was considered as inappropriate skill. The level of skills in each of the fields was reported in the form of frequency and also the effect of related factors on skill score was measured with Pearson correlation coefficient and linear regression model.

All of students received the appropriate skill score. Students had the highest level of skill in the field of “giving necessary advice to the parents. The lowest level of skill was in the field of “complete caries removal”. The overall score had the most correlation with “practical pediatric dentistry 2 score” (p=0.682), then “practical pediatric dentistry 1 score” (p=0.561) and   finally “total average” (p=0.356). 93% of students received the appropriate skill score. Students had the highest level of skill in the field of “discipline and good behavior”.  The lowest level of skill was in the field of “convexity of the axial wall of box”. The overall score had the most correlation with “theoretical pediatric dentistry 1 score” (p=0.840) and then “total average” (p=0.240). Overall score was not correlated with age and gender with P˃0.05

Study in general showed that the level of dentistry students’ skills in restorative treatments at pediatric preclinic & clinic stages is appropriate.

In the world of dentistry, new materials and technologies are rapidly advancing. These advancements allow dentists to offer more efficient, precise, and comfortable treatment options to their patients. This study aimed to explore the experiences of general dentists in the city of Yazd with new dental materials and technologies.

This qualitative study, using a phenomenological approach, was conducted on 10 general dentists in Yazd in 2023. Participants were randomly selected, and data were collected through in-depth and semi-structured interviews. The interviews were recorded and then transcribed into text. Relevant content related to the study's objectives was extracted from the transcripts, coded, and categorized. Data analysis was performed manually using content analysis methods.

Dentists became familiar with new materials through the internet, virtual spaces, companies, and vendor websites, colleagues, various congresses, and refresher courses. They were introduced to new dental technologies through training courses, offline educational materials, refresher courses, colleague and specialist recommendations, and virtual spaces. The criteria for selecting new dental materials by participants included quality, price, handling ability, company advertisements, colleague recommendations, and the dentist's own evaluation. The criteria for selecting new dental technologies included implementation methods, article and reference approval, price, and colleague experience.

It seems that general dentists in Yazd are highly interested in using new materials and technologies in dentistry. This enthusiasm is due to the numerous advantages of new materials and technologies, including increased precision, efficiency, and comfort in providing services to patients. Additionally, given the rapid pace of advancements in dentistry, there is a need for continuous support for dentists to keep their knowledge and skills up to date. Therefore, emphasizing the importance of continuous education and updating dentists' information can significantly contribute to providing better and more efficient services to patients.