Journal of Dental Medicine
Year:2017 | Volume:30 | Issue:2|Papers Count:9

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, DE was in acceptable range (1.98). For CE (D=5.38) and VM7 (D=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.