Journal of Dental Medicine

The Guided Bone Regeneration (GBR) treatment concept advocates that regeneration of osseous defects is predictably attainable via the application of occlusive membranes, which mechanically exclude non-osteogenic cell populations from the surrounding soft tissues, thereby allowing osteogenic cell populations originating from the parent bone to inhabit the osseous wound. The use of membrane to exclude non-osteogenic cells, is a key principle of guided bone regeneration. A large number of membranes have been evaluated in clinical and experimental studies. The object of this study was to review the literature regarding guided bone regeneration and all types of membranes that were used in this technique. 72 articles between the years 1968 through the 2016 from PubMed, Medline and Google Scholar using the related keywords, were selected. Finally, we concluded that the modification of mechanical and physico-chemical properties of membranes could improve the process of new bone growth. However, determination of the exact role of membrane porosity in this process, still needs to be clarified. Optimization the chemical composition of membrane with the focus and attention to obstructive property and bioactivity, is an important point in this research field. Various factors such as flexibility, mechanical strength and degradation rate determine the type of membrane used for bone tissue regeneration.

Background and Aims: The aim of the present study was to evaluate the effect of applying hydrophobic resin after use of different generation of the bonding systems on nanoleakage.
Materials and Methods: 20 third molar teeth were selected. The teeth were randomly divided into 4 groups of 5, each was treated using the fourth, fifth, sixth, and seven generation of dentin bonding. Then, the crown of teeth was sectioned from the CEJ region and each specimen was divided into two halves with mesiodistal cut, one half for the application of dentin bonding without the addition of a hydrophobic resin, and the other for the same dentin bonding by the addition of a hydrophobic resin. Afterwards, the specimens were restotred by composites. After placement of specimens in silver nitrate, the amount of nanoleakage was evaluated by SEM. Data were analyzed using a repeated measurement statistical analysis (α=0.05).
Results: The use of hydrophobic resins decreased nanoleakage and range of variations in all groups (P<0.05). This reduction was greater for total-etch dentin bonding. Higher degree of nanoleakage occurred in total-etch dentin bonding in most evaluated areas. In general, Clearfil S³ bond showed the least percent of the nanoleakage.
Conclusion: All dentin bonding systems showed some degree of reduction in nanoleakage after hydrophobic layer application and the reduction was greater in Total-etch adhesives systems.

Background and Aims: Methicillin-resistant Staphylococcus Aureus (MRSA) is an important infection source in dentistry for different disinfectants to be used to prevent its transmission. Furthermore, a variety of chemical disinfectants are developed to remove bacterial infections from the dental care workers' hands and claims are made regarding their superiority in infection control, although all requires scientific investigations. The aim of present study was to compare the effects of chemical hand-disinfectants Micro Zed HD, Aseptoman and Decosept on MRSA (methicillin resistant staphylococcus aureus) in different periods of time.
Materials and Methods: In this experimental study, the antibacterial efficacy of three hand-disinfectants on standard strain of MRSA (USA300: ATCC® BAA-1717™) was evaluated according to European standard of evaluating antiseptics (EN 1040:2005 CSN EN). First we prepared a 0.5 Mc Farland (108 CFU/ml) suspension of MRSA, and exposed to three disinfectants for 15, 30, 60 and 90 seconds. Then, they were transferred to separate plates of Mueller-Hinton medium and incubated in 37^◦C for 24 hours. The plates were compared then with control plate to evaluate the efficacy of materials on bacteria by calculating the CFU/ml of plates.
Results: Three hand-disinfectants evaluated in this study had the maximum anticabterial effect on MRSA in the minimum time of exposure (15 seconds), and we found no trace of growth in any plates.
Conclusion: The three hand-disinfectans (MicroZed HD, Aseptoman and Decosept) in the concentration suggested by their companies, showed no difference in efficacy to remove MRSA from hands.

Background and Aims: Regarding the high prevalence of caries and oral dental diseases, especially in the elderly, and the increasing attention of people to using the concept of quality of life, this study was conducted to determine the relation between oral and dental health and the quality of life in elderly people in Yazd.
Materials and Methods: This cross-sectional study was performed using data from the Yazd Public Health Survey (YAHS) with a sample of 9293 people, in 1393-94. All information was collected from 1907 elderly people aged between 60 to 70 years, including quality of life and oral and dental indexes from the comprehensive questionnaire of YAHS. Data were analyzed by independent t-test and Spearman correlation coefficient using SPSS16 software.
Results: There was a significant relationship between the quality of life and oral hygiene (P<0.01). Also, the score of quality of life and oral health was significantly related to education (P<0.01).
Conclusion: This study showed the positive relation between the oral health the quality of life. In addition, there was a quality of life level in the elderly people with poor oral hygiene.

Background and Aims: One of the most important challenges for dentists is providing a crown with appropriate marginal fit and gap. The 135-degree tooth preparation found to have some advantages such as technical ease and appropriate finish line record. Despite the advantages of 135-degree tooth preparation, scant research has been done in this area. Therefore, the aim of this study was to compare 135-degree and deep chamfer tooth preparation on the marginal fit and marginal gap of posterior metal-ceramic crowns.
Materials and Methods: Deep chamfer and 135-degree tooth preparation were performed on the two first mandibular molars with healthy coronal tissue and similar size. Impression was taken from each tooth and 30 crowns were made on each die. The sample plastered with fit checkers were pressed under the force of 40 N for 3 min in a universal testing machine. They were measured and recorded under a loop with 40x power in three points on each aspect. Data were analyzed by Wilcoxon and Kolmogorov-Smirnov tests using SPSS version 24.
Results: The mean marginal fit values in deep chamfer and 135-degree were 48.5417µm and 55.3333 µm, respectively with no statistically significant difference (P>0.05). While the mean marginal gap in deep chamfer (2.4833 µm) was significantly higher (P<0.05) than 135-degree (1.0083).
Conclusion: It can be concluded that the marginal gap by 135-degree’s tooth preparation was lower than that of deep chamfer in metal-ceramic crowns. However, no significant difference in the marginal fit between the deep chamfer and 135-degree tooth preparation was found.

Background and Aims: Immediate implant placement following tooth extraction is a treatment with many advantages. Alveolar bone preservation after immediate implant, need minimum of 2 mm thickness in buccal bone plate. The aim of this study was to evaluate the thickness of buccal cortical bone of maxillary premolars by Cone Beam Computational Tomography (CBCT) technique.
Materials and Methods: In this descriptive epidemiological study, Cone Beam Computed Tomography image was obtained from 29 patients (male and female) referred to the radiology department of Jundi Shapoor dental school of Ahvaz from 1393 (Mehr) to 1394 (Shahrivar) for implant insertion insertion. The thickness of buccal cortical bone was measured in 3 and 5 mm apical to the CEJ and root apex, perpendicular to the longitudinal axis. All the measurements were done by two oral and maxillofacial radiologists, separately. Data were analyzed by SPSS22 software, using descriptive statistics, and T-test.
Results: The thickness of buccal cortical bone in second premolar was significantly more than 1 mm (P=0.001), but in first premolar, the thickness was close to 1 mm with a non-significant difference (P=0.29).
Conclusion: The results of this study showed that immediate implant insertion could be done in the maxillary second premolar area with more predictability compared to the first premolar area.

Background and Aims: Enoxolon is a natural licorice and its formula is similar to cortisone. The aim of this double blind randomized match control clinical trial, was to analyze the effect of Arthrodont toothpaste containing 1% Enoxolone on dental plaque, gingival inflammation, and bleeding indices.
Materials and Methods: 40 patients who had gingivitis were selected. They were instructed to brush their teeth twice daily for three minutes then massage the gums with pastes for one minute and then wash their mouths. The patients were divided into two groups: The Arthrodont toothpaste containing Enoxolon, was given to the study group and the Crest toothpaste free of Enoxolon, was given to the control group. At the beginning of the study and after 21 days, plaque, gingival, and bleeding indices were measured. The statistical analyses were done by Paird T test, T test and nonparametrical analysis of Wilcoxon and Mann-Whitney.
Results: In both groups, the three indices decreased significantly. Comparing between the two groups, the gingival and bleeding indices had significantly decreased in the study group (Arthrodont toothpaste) compared to the control group (Crest toothpaste). However, no significance difference in the plaque index between the two groups was found (P=0.143).
Conclusion: The results of this clinical study showed that Enoxolon had anti-inflammatory effect on gingivitis.

Background and Aims: Removable partial denture (RPD) is a common treatment to restore partially edentulous areas; however, a limited number of studies have been made on oral hygiene habits among patients with RPD. The aim of this study was to evaluate the patients’ knowledge about various cleaning methods of RPD to consciously improve hygienic habits of the patients.
Materials and Methods: This study was a cross-sectional study performed on 96 RPD patients referred to Jundishapur faculty of dentistry from 1395 to 1396. Demographic data namely age, sex, level of education, and other information about general health status, duration of dentures usage, and denture cleaning frequency were taken by the census through questionnaires. The descriptive statistics, chi-square, and T-test were used for statistical analysisof data (P<0.05).
Results: The patient age, sex, and smoking habits had significant effects on the prosthesis maintenance habits (P<0.05). The patients over 50 years of age, females, and nonsmokers significantly preferred dipping method over other RPD storage methods (P<0.05). The frequency of denture cleaning was significantly greater in males (53.3%) compared to females (23.9%) (P<0.05).
Conclusion: According to the results of this study, most RPD patients did not clean their dentures appropriately and have little knowledge on how to maintain and clean them. Regular and periodic recall and written instructions might be helpful to improve patients' awareness on proper cleaning and maintenance of partial dentures.

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: Due to the review of general dental courses, it was necessary to assess the students' satisfaction with this curriculum. The aim of this study was the assessment level of students’satisfaction with the new educational curriculum of the Ministry of Health at the department of restorative dentistry of Tehran university of medical sciences in 2019-2020.
Materials and Methods: In this descriptive cross-sectional trial,72 sixth year dental students of Tehran University who passed the restorative dentistry courses based on the new curriculum were studied. A questionnaire was developed and for validity content assessment, it was presented to 5 professors and then revised. For reliability approval of the questionnaire, test-retest approach was used. The questionnaire was given to the 30 students of the main pilot group in one session and two-week later and agreement percentage and Kappa index were calculated.  After conducting the "test" process and re-testing, the "questions" were statistically analyzed using STATA software.
Results: The most level of satisfaction regarding to practicality of subjects was found for fundamental of restorative dentistry including principles of amalgam class I cavity preparations and restorations on the dentic (81.94% and 76.39% acceptable respectively) and the principles of amalgam classII cavity restorations on the dentic (72.22%). The least satisfaction levels were obsereved in the first and second theoretical restorative courses including tooth-colored restorations (47.22%), onlays and inlays (47.22%) and tooth-colored classII cavity preparations and restorations (48.61%). The amount (P-value or error of the first type) was reported in all questions>0.001.
Conclusion: Despite the limitation of this study, final-year dental students’ satisfaction of theoretical restorative dentistry courses was medium, while it was high for the fundamental and practical restorative courses of 2017 educational curriculum.

Background and Aims: 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.
Materials and Methods: 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.
Results: 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.
Conclusion: 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.

Background and Aims: Dentists faced the highest risk of infection during the COVID-19 pandemic. Educating competent students is the first task of the dental school to overcome the created problems and thus, it is necessary to recognize the created educational deficiencies. This study aimed to assess the students' perspectives from the Dental School at Tehran University of Medical Sciences during the academic year 2019-2020, concerning the competencies expected to be developed during the clinical phase of the general dentistry curriculum during the COVID-19 pandemic. The findings are intended to inform the formulation of educational strategies in the post-pandemic period to address identified gaps in training.
Materials and Methods: During the academic year 2019-2020, a cross-sectional descriptive study was conducted at the School of Dentistry, Tehran University of Medical Sciences, Iran. The study consisted of three phases: checklist design, psychometrics, and a survey of general dentistry students in their third to sixth year. The checklist design phase involved a team of four individuals, including educational officials from the faculty, academic staff members, and medical education experts. Experts confirmed the content validity of the checklist, while reliability was assessed using the Intraclass Correlation Coefficient (ICC), which indicated favorable validity and reliability. Subsequently, questionnaires formatted as Google Forms and a census approach were distributed to all students enrolled in the general dental course within the clinical section of the School of Dentistry at Tehran University of Medical Sciences. Ultimately, following the data collection process, statistical analysis was conducted utilizing descriptive statistics, including the mean and standard deviation, and the findings were communicated to the group managers.
Results: The assessment of content validity was established at a minimum of 71%, based on the evaluations provided by five experts. Additionally, reliability was measured using an intra-cluster correlation coefficient (ICC) exceeding 0.79, signifying a strong level of both validity and reliability. 122 students (53%) in the clinical stage completed the forms related to the pre-clinical/clinical units passed during the Covid era. Despite having enough training, basics Removable Partial Prosthodontics, Surgery 1, and Restorative 3 courses needed more training. In addition, Basics Removable Partial Prosthodontics, Surgery 1, and Surgery 4 needed the most practical training to acquire the necessary competencies.
Conclusion: The findings of this research indicated that the dental students expressed a desire for increased practice across various levels of pre-clinical and clinical courses. This would suggest that the challenges associated with patient interactions during the COVID-19 pandemic may not be the sole contributing factor. Consequently, alongside the need for educational planning to address the requirements of enrolled students, it appears essential to conduct similar studies in the post-pandemic context. Furthermore, this approach may also prove beneficial in evaluating educational needs for ongoing professional development courses.