Journal of Dental Medicine

Background and Aims: Opinion of students regarding the content, structure and quality of their training is a fundamental part of holistic evaluation of curriculum, and serves as an important information resource in policy making. In the present study, we aimed to contribute to the development, assessment and evaluation of the new national dental curriculum through evaluation of last-year dental students’ opinions regarding undergraduate dental curriculum.

Materials and Methods: This cross sectional questionnaire survey was done in 2010-2011 academic year. The target population was last-year dental students in 15 Iranian state dental schools. In these schools, all last-year dental students were invited to participate in the study. The chi-square test served for statistical analyses.

Results: In total, 432 students (68.4% female) participated in the study. Of the respondents, 72.4% (60.7% of male and 77.6% of female, P=0.001) believed that their undergraduate dental training had been completely inadequate or inadequate. Only about one third of students believed that educational methods during their undergraduate dental training had been appropriate or completely appropriate.

Conclusion: In general, it seems that undergraduate dental training from students’ view point has not been appropriate in terms of both content and method. The results show the necessity of revision of national undergraduate dental curriculum.

Background and Aims: Trauma to the permanent and deciduous incisors is an undesirable common event in childhood. Proper immediate management of injured teeth is depended on the knowledge of unprofessional people, including teachers, who are usually present at the scene prior to dental treatment. The aim of this study was to assess the knowledge and self-reported practice of primary school teachers on the emergency management of traumatic dental injuries (TDIs) in Arak.

Materials and Methods: In this cross-sectional study, 624 primary school teachers were enrolled in census in Arak. An anonymous questionnaire containing demographic data, the history of previous exposure to traumatic dental injuries, teachers’ knowledge regarding emergency management of TDIs and their practice towards TDIs was used. Questionnaires were distributed among all participants and then were collected on the same day. Descriptive statistics and linear regression were performed to analyze the data.

Results: A total of 292 completed questionnaires (response rate 46.8%) were collected. The mean score of knowledge was 2.65±1.69 out of 10. The mean score of self-reported practice was 3.46±2.04 out of 8. Regarding the demographic variables, knowledge had a significant relationship with the education (P<0.001). No significant relationships were observed between the self-reported practice and demographic variables. The correlation coefficients between the knowledge scores and the practice scores of teachers was 0.2.

Conclusion: This study revealed that insufficient knowledge exists among primary school teachers on emergency management of TDIs. Furthermore, a high percentage of respondents enjoy a significant deficiency regarding favorable practice encountering TDIs.

Background and Aims: Dental caries is an infectious disease transmitted by multiple factors in the mouth and one of the most common chronic diseases in the world that requires a lot of treatment expenses. The aim of this study was to evaluate the effect of fluoride 0.2% and Fuchs mouthwash (a combination of xylitol and fluoride 920 ppm) against two bacterial growths (Streptococcus mutans and Lactobacillus acidophilus).

Materials and Methods: In this in vitro study, first the well diffusion method and then MIC method (minimum inhibitory concentration) were used. Data were analyzed with Excell (2016).

Results: The results of the MIC method showed inhibitory effect of both mouthwashes in pure concentration (128 μg/ml). However, fluoride was effective in concentration higher than 32 μg/ml for Streptococcus mutans and higher than 2 μg/ml for lactobacillus acidophilus. Fuchs was effective for both bacteria at concentration higher than 64 μg/ml and in lower concentration it was ineffective. The results of the well diffusion test showed the inhibition of fluoride mouthwash in pure concentration on the Streptococcus mutans was (17 mm) and on the lactobacillus acidophilus 24 mm was obtained. In Fuchs mouthwash was zero and it represented effectiveness of fluoride on bacteria and ineffectiveness of Fuchs.

Conclusion: The fluoride mouthrinse in different concentrations, because of having a good inhibitory effect in both methods on Streptococcus mutans and Lactobacillus acidophilus was more effective compared with that of Fuchs mouthrinse.

Background and Aims: Delay in light irradiance can improve the polymeric structure and mechanical properties of resin cement and uniform stress distribution. The aim of this study was to evaluate the effect of light activation modes (immediate, 5 and 10-minute delay) on the push-out bond strength of cemented fiber posts with two types of resin cements in different of root canal regions.
Materials and Methods: In sixty extractedsingle canal and endodontic therapied roots, FRC Postec Plus were cemented with two resin cements, Nexus3 and Panavia F2.0, in three curing methods, immediate, 5, and 10 minute delay. After 24 hours storing in a dark place, they were cut into three sections: coronal, middle and apical. The push-out bond strength test was performed using the universal testing machine. Failure modes were evaluated using stereomicroscope. Data were analyzed by ANOVA and Tukey post hoc test with P<0.05 as the level of significance.
Results: In Nexus3, the immediate light curing had significantly higher bond strength (11.18±4.32) than delay methods (P=0.001). In Panavia F2.0, the 5-minute delay had significantly the highest bond strength (13.34±4.62) (P<0.05). There was no correlation between the different light curing methods and root canal regions. In Nexus3, the coronal region had higher bond strength (11.83±3.7) than that of middle (9.12±3.1) (P=0.015), and middle than of apical (5.65±2.77) (P=0.00), and coronal than that of apical (P=0.002). In Panavia F2.0, there were not significant differences among regions (P>0.05).
Conclusion: Delay in light curing of dual-cure resin cement's had different effects on the push-out bond strength.
 

Background and Aims: Increase of esthetic demands among dental patients has led to development and wide spread use of tooth colored ceramic systems for fabricating fixed restorations. However, they do not have same capability of matching the target color. The aim of this study was to compare the color coordinates of three widely used systems with A2 tab from a Vita Lumin Classic shade guide.
Materials and Methods: In this study, three ceramic systems were tested. The metal-ceramic(MCR) with 0.5 mm core and 1 mm Ceramco lll veneering layer; the all ceramic (CE) with 0.5 mm Cercon core and 1 mm Cercon Ceram veneering layer, and the all porcelain (VM7) with 1.5 mm Vita VM7. For each system, 15 disks (1.5mm×10mm) were made in Vita A2 shade. L*a*b* coordinates of the samples were measured by spectrophotometer and the color difference with Vita A2 shade was calculated. The data were analyzed using one way ANOVA and multiple Tukey tests.
Results: The color coordinates of the target shade was L*=72.45, a=1.59 and b*=14.11. The mean L*a*b* values for MCR were 72.61±0.38, 2.88±0.24, 15.51±0.64, for CE were 76.42±0.46, 2.77±0.14, 17.51±0.61, and for VM7 were 75.13±0.6, 2.15±0.19, 17.9±0.61, respectively. The difference between coordinates of each system with target shade was significant. Only for MCR group, ΔE was in acceptable range (1.98). For CE (Δ=5.38) and VM7 (Δ=4.72) groups, the difference was unacceptable.
Conclusion: Under the condition of this study, the metal-ceramic system had the best and acceptable match to the target shade.
 

Background and Aims: In recent years, dental implants have received special attention in dentistry. Due to the remarkable success of predictable dental implants, there is growing interests in the scientific community from descriptions of implant success toward identify factors associated with implant failure. The purpose of this study was to identify the risk factors associated with implant failure in an objective and statistically valid manner.
Materials and Methods: To address the research purposes, we used a cohort study in which a total of 2368 implants were placed on 1011 patient in the Clinic of Tehran University of Medical Sciences. The predictor variables included demographic variables, the health status and variables are related to implants. The outcome variable of interest was implant failure. The overall implant survival was estimated using the Kaplan-Meier analysis. First, risk factors were identified using Chi-square test and Fisher's exact test and then the Cox proportional hazard regression models were used for more analysis.
Results: The overall 39 month implant survival using the Kaplan-Meier function was 0.99±0.002. The implant location (jaws) (P=0.049) and type of teeth (P=0.011) were found to have significant relation with failure times in Cox proportional hazard model.
Conclusion: According to result of this study, both implant location and type of teeth had effection the failure times so that, the survival in mandible was higher than maxilla. The failure rate was higher in anterior teeth than that of others (molar, premolar, canine and primary).
 

Background and Aims: Cancer is the second most common cause of death in developed countries. The goal of this study was to determine the important epidemiologic factors affecting diagnosis and survival rate of patients with laryngeal SCC, for prevention, control and increase longevity.
Materials and Methods: In this study, all the cases recorded at the Center of Cancer Office of the Iran Ministry of Health in Tehran between 2005-2009 were examined. From 513 cases, 279 that their follow-up was possible by phone or postal address were included in the study. Data collection were performed from questionnaire. The data were analyzed by SPSS version 20. The Kaplan Meier survival curves were utilized and, moreover, the corresponding influential factors were examined by using the Cox regression test.
Results: The mean age of patients were 61.1 years (SD=10.54). The gender of 92.1% of patients were male. The most widely used method for the treatment was a combination of three methods of surgery, radiation therapy, and chemotherapy. The overall five-year survival rate was 75.7% (SD=0.03). The gender, histological differentiation, and professional delay did not exhibit a statistical correlation with the survival rate (P=0.38, 0.14, 0.52), whereas the age and patient delay had a statistically significant relation with the survival rate (P=0.03, 0.07).
Conclusion: The survival rate was lower in older patients. Patient and professional delays were high, which need more attention for improving the quality of life.
 

Background and Aims: First molar has an important role at individual’s dental health. Among the known risk factors, the experience of previous caries is of the best predictors for future caries. The aim of this study was to examine the association of primary teeth caries and other risk factors with the incidence of permanent teeth caries by considering the caries extent and severity.
Materials and Methods: This case-control study was done on 150 students from second and third grade with 9 years old. Cases included children with at least one carious permanent molar. Caries-free students who were matched based on the gender and mother education was considered as control group. Examination was done on dental unit under the unit light with blunt explorer and mirror for visual assessment. DMFT, dmft and caries severity (D1-D3) were recorded based on WHO standards. Data were calculated using SPSS18, Correlation, Chi Square Analysis, Odds ratio and Logistic regression.
Results: Linear correlation between dmft in primary teeth and DMFT in permanent molars was obtained with r:0.34 (P<0.001). Decay in permanent molars in students with active caries in primary molars was 3.3 times more probable than others. In regression model, the other risk factors such as cariogenic diet, mother`s education, brushing with toothpaste, flossing, using flouride, and regular dental visiting were not significant (P>0.05).
Conclusion: Caries-free primary teeth predicts permanent teeth without decay with a high possibility. It could be helpful in caries risk assessments.
 

Background and Aims: In modern societies, the incidence of oral cancer is increasing. It may be due to the increased population, life expectancy, and exposure to risk factors. This increase can particularly be seen in women and in our own country, Iran. The aim of the present study was to explore the status of care and treatment of patients with oral cancer referring to Shariati educational hospital in Tehran, during the years 2003-2013.
Materials and Methods: The present study was a cross-sectional descriptive survey on oral cancer patients attending the Shariati hospital in Tehran during a ten-year period. Data were collected through patient records and statistically analyzed by SPSS21 software.
Results: Regression analysis was performed in 5 models, where variables such as age, gender, location of the tumor, stage and grade was entered as independent variables and delay in treatment (time interval from diagnosis to treatment) entered as the dependent variable. The analysis showed that the elapsed time from diagnosis to treatment had a positive association with age of the patients. It means that the higher the age, the more delay in treatment (P<0.05). No relationship was found between the treatment delay and gender, tumor location, grade, and stage.
Conclusion: Considering the consequences of oral cancer for patients, there was necessity to formulate plans for preventing, early detection and improving quality of life in oral cancer patients.
 

Background and Aims: By measure of scientific publications, it is possible to present a real picture of scientific activities of a country. In this regard, based on joint work to achieve specific objectives that typically produce knowledge and scientific information, scientific and research cooperations are defined. Therefore, the purpose of this study was to analyze the scientific collaborations in Iranian dentistry articles in Scopus during 2010‐2014.
Materials and Methods: The population was Iranian dental articles which were indexed in Scopus during 2010‐2014. Finally, the results were presented in the format of tables and diagrams.
Results: The findings showed that scientific cooperations were increased in the field of dentistry during 2014-2010 in the Scopus. Tehran University of Medical Sciences had the most publications. The rate of index, degree and coefficient of collaboration during 2010-2014, were 4.23, 0.97 and 0.71, respectively with relatively high values. Most of the articles during the 2010-2014 were four, three, and five authored articles were the first, second and finally the third position of occurrence rate. Our data suggested that the lowest number of articles were related to articles with 9 authors or more.
Conclusion: According to the results of this study, it can be concluded that the Iranian prosperity of scientific publication in the field of Dentistry is growing. Furthermore, the results showed that the Iranian authors and researchers have tendency to scientific collaboration with other researchers in groups.
 

Background and Aims: Disabled individuals are involved with several oral health problems. The aim of this study was to assess the knowledge and perspective of dentists towards oral health promotion in disabled individuals.
Materials and Methods: Dentists participating in the fifty-fourth International Congress of Iranian Dental Association in 1392 in Tehran were invited. A valid and reliable questionnaire including the information about age, gender, city of practice, the working experience with the disabled was distributed. There were also 13 questions on knowledge and one question about the importance of training in the field of “oral health promotion of the disabled” in this questionnaire. The data were analyzed by linear regression model by SPSS 18 software.
Results: 117 questionnaires were collected and evaluated. The mean age was 35.5 (10.1) years. Among the participants, 53.8% were male and 46.2% were female. Average score of knowledge was 6.5 of the maximum attainable 13. Among the dentists, 60% believed that receiving education on oral health promotion for the disabled is important. Liner regression model which evaluated the effect of confounding factors showed that aging led to reduction in dentists' knowledge of oral health of the disabled. Furthermore, working experience with the disabled led to the increase in knowledge. Dentists who had previously treated a disable individual were more interested in receiving related training.
Conclusion: Knowledge of dentists in the field of oral health promotion of the disabled is not desirable while most dentists recognize the need for training. This issue emphasizes on the need for a broader educational effort.
 

Background and Aims: The aim of this study was to assess the microhardness of BioMTA (OrthoMTA, RetroMTA) in distances of 0.5, 2 and 3.5 mm from the exposed surface to blood, phosphate buffer saline (PBS) or distilled water and to compare to that of ProRoot MTA.
Materials and Methods: One hundred and thirty five semicylindrical polymethyl methacrylate were filled with either ProRoot MTA, OrthoMTA, or RetroMTA. Fifteen molds in each group were exposed to blood, 15 molds to PBS and the other 15 to distilled water. The microhardness of the materials at 0.5, 2 and 3.5 mm distance from the exposed surface to phosphate-buffered saline (PBS) as a synthetic tissue fluid, blood, and distilled water was assessed. The data were analyzed using one-way ANOVA and Tukey post hoc tests.
Results: Exposure to blood significantly decreased the microhardness of all materials at all three points of 0.5, 2 and 3.5 mm (P<0.001). At level of 0.5 and 2 mm distant from blood, OrthoMTA showed significantly the least microhardness value; however, at the point of 3.5 mm, the microhardness of RetroMTA was higher than the two other materials (P<0.001). After exposure of samples to distilled water or PBS, no significant difference was found between the materials at any levels of 0.5, 2, and 3.5 mm (P<0.01).

Conclusion: Blood exposure resulted in the decrease of microhardness of internal part of the materials.

Background and Aims: Poor adhesion between porcelain and some of the dental alloys is one of the most challenges to select the desirable alloy in dental restorations. Therefore, the aim of this study was to evaluate the bond strength of porcelain to some of the commercial alloys. This can help in selection of desirable alloy.
Materials and Methods: The shear bond strength of porcelain to the three of the most widely used nickel-base dental alloys commercially named as: Verabond, Damcast and Noritake were evaluated according to standard ASTM E4. The results were analyzed based on the statistical method of independent t with the meaningful level of P<0.05. Then, the bonding interface of the fired samples was evaluated using SEM equipped with EDX analyzer and X-ray diffractometry.
Results: The average bonding strength of porcelain to each of the above mentioned alloys were determined as: 27.54±5.48, 22.46±4.99 and 26.18±4.27 MPa, respectively. Due to the existence of Be and Al in the chemical composition of Verabond and Damcast and their higher appetencies to form the different surface oxides in preference to Cr₂O_3, not only the bond strength of porcelain to two these alloys was increased about 20 percent (compared with the Noritake), but also the color of their porcelain was not changed.
Conclusion: To replace the replacing of deleterious elements from the chemical composition of dental alloys. The added new elements should control through the oxide layer and the formation of Cr₂O₃ in porcelain-alloy interfaces for adequate bond strength.

Background and Aims: The aim of this study was to evaluate the effects of two fluoride containing mouth rinses on the color stability of two different resin composites.
Materials and Methods: 27 specimens (2×4×5 mm) were prepared from each of the following materials: a micro filled composite (Gradia, GC) and nanohybrid (Grandio). The specimens were polished by Soflex fine and superfine disks and then incubated in artificial saliva at 37°C for 24 h. The baseline color values (L, a, b) of each specimen were measured using an Easyshade spectrophotometer according to the CIELab color scale. The specimens were immersed in 20 mL of each mouth rinse and stored in an incubator at 37°C for 12 h. After incubation, the color values of all specimens were measured again, and the color change value (ΔE) was calculated. Data were analyzed by a 2-way analysis of variance at a significance level of 0.05.
Results: None of the mouth rinses created clinical significant color changes in the samples. There was no statistically significant difference among color susceptibility between resin composites (P=0.330). The interaction between the effect of mouth rinses and type of restorative materials was not statistically significant (P>0.05).
Conclusion: Accordance to the results of this study, the fluoride containing mouth rinses does not create color change in resin composites.

Background and Aims: One of the main disadvantages of light cured composite resin materials is polymerization shrinkage upon curing. This leads to the microleakage of restoration and finally failure of the restoration. The purpose of this study was to investigate the effect of two types of light curing devices with different modes on the microleakage of posterior composite filling in Cl II restorations.
Materials and Methods: In this experimental study, 30 extracted sound molar human teeth were collected. All specimens were randomly divided into 3 groups of ten: Standard LED irradiation, pulse curing LED irradiation and QTH irradiation. All samples were prepared with mesial and distal boxes and composite fillings were done with three different light curing patterns for 20 s. After thermocycling, the specimens were kept in 2% methylene Blue solution for 24 h for microleakage test. After sectioning, the samples were evaluated by a stereomicroscope. For data analysis one-way ANOVA and Kolmogorov-Smirnov were used. P<0.05 was considered statistically significant.
Results: The quantitative tests showed that there were no statistical difference between study groups (P>0.05).
Conclusion: The results showed that both light curing devices were effective and no significant difference between different modes of LED light curing device on microleakage of class II composite restorations was found.

Background and Aims: To create a good adhesion between porcelain veneers and zirconia restorations has been important issues is the prosthesis. The aim of this study was to identify an effective way to prepare the zirconia surface infrastructure to increase its shear bond strength to the porcelain veneer.
Materials and Methods: 75 samples of zirconia (Y-TZP) cylinders (diameter of 7 mm and a thickness of 3 mm) were fabricated. Based on the surface treatment, specimens were randomly divided into 3 groups: control, air abrasion and
Er-YAG laser. After surface treatment, the specimen surfaces were examined by SEM. Using a metal mold, the porcelain was veneered on the zirconia surface and then fired. After thermocycling, the shear bond strength of porcelain to zirconia was measured and then the failure mode of each specimen was analyzed using a stereo-microscope. Data were analyzed by one-way ANOVA and Tukey test.
Results: Significant differences were observed between the mean shear bond strength of different groups (P=0.001). The greatest amount of shear bond strength was observed in the group (S) and the lowest bond strength in the control group. Analysis of failure modes showed no statistically significant difference in the type of failure among study groups. The adhesive failure was predominating failure at the intersection of porcelain veneers.
Conclusion: The highest shear bond strength between zirconia and porcelain was achieved by sandblasting the zirconia surfaces compare with that of Er_YAG application.

Background and Aims: The purpose of this study was to evaluate the sealing ability of MTA and cold ceramic by using bacterial leakage method.
Materials and Methods: In this experimental study, fifty human single root extracted teeth were chosen. In group A, 20 teeth were filled with MTA and in group B, 20 teeth were filled with cold ceramic. Five teeth were used as a positive control (obturated using gutta-percha without sealer), and five teeth were used as negative control (obturated using gutta-percha with AH26 sealer and coated with two layers of nail varnish). A bacterial leakage model utilizing Enterococcus faecalis was used for evaluation of the sealing ability. The teeth were placed in test tubes, so that they formed two upper and lower compartments. The cultured bacteria in the upper chamber were in contact with the coronal area of the tooth. The root end was placed in the lower chamber containing sterile culture media. In this case, the filling of the root canal was only the communication path between the upper and lower chambers. In this method, the presence of turbidity in the lower chamber indicated that bacteria had penetrated through barrier and reached the medium. The leakage was measured. The acquired data was analyzed using Chi-square test.
Results: In group A (MTA), 7 samples and in group B (Cold ceramic), 4 samples should the leakage. In regarding the leakage, there was no statistically significant difference between MTA and cold ceramic. (P=0.288)
Conclusion: The results showed that the sealing ability of MTA and cold ceramic was similar as root filling materials.

Background and Aims: Headache is among the most common complaints in patients suffering from temporomandibular joint disorders (TMD). Thus, it seems that evaluation of patients with headache in terms of temporomandibular joint (TMJ) disorders is necessary. In people with TMD, parafunctional activities play an important etiologic role. Considering the high prevalence of bruxism and TMDs in patients with headache, assessment the accuracy and severity of this association can play a key role in diagnosis and treatment of these two phenomena. The purpose of this study was to investigate the relationship between bruxism, TMD and headache, also assessment the efficacy of TMD conservative therapy with a special approach to self-management in treating patients with headache.
Materials and Methods: Motor searches of Cochrane, Medline and EMbase databases, PubMed, Google Scholar, Uptodate, BMJ clinical Evidence, MD consult and science direct by using of relevant key words were searched for article published between 2000 and 2015. A total of English language abstracts were reviewed, 80 full articles were obtained and among them, 30 relevant articles were reviewed in this study. Because of the high number of studies in this field, we divided the data into four group, bruxism and TMD, TMD and headache, bruxism, TMD and headache, treatment.
Conclusion: Bruxism and temporomandibular disorders are the two main contributing factors in initiation and perpetuation of headache. Treatment of these two phenomena would be effective in the treatment of headache.

Background and Aims: Radiopacity is an essential requirement for all restorative materials. Radiopaque materials allow the dentist to diagnose and assess radiographically the restoration, primary caries, assessment of contours, overhang and secondary caries. The aim of this study was to evaluate the radiopacity of two types of dental bases and liners in comparison whit dental structure using a digital radiography system.
Materials and Methods: Two classes of materials were prepared: 1 mm and 2 mm thickness disks for glass inomer and 1 mm and 0.5 mm thicknesses for dycal. Specimens of enamel and dentine with the same thicknesses were obtained. As a control, an aluminum step wedge was used. Samples were positioned over a phosphor-ray, plate of min ray soredex system, exposed, and the images were analyzed using the contour dent software. ANOVA analysis was used to investigate the significance of differences among the groups. For pairwise comparisons, the Bonferroni test was applied (P<0.005).
Results: 0.5 mm diameter of self-cure and light cure dycal and enamel, presented radio-opacity higher than that of dentine, except for the light cure dycal that had radiopacity lowers than enamel. 1 mm diameter of all the groups presented higher radiopacity than dentin. Light cure and self-cure glass inomer and self-cure dycal presented radiopacity higher than enamel. Enamel showed radipacity higher than light cure dycal in 2 mm diameter self-cure. Light cure glass inomer presented radiopacity higher than that of enamel and dentin.
Conclusion: The increased thickness of the materials evaluated increased their radio-opacity. It was concluded that all the materials had lower radiopaaty than dentin. Only enamel showed higher radiopacity than light-cured dycal.