Evaluation of Microleakage at the Junction Between Combined Amalgam/Composite Resin Restorations Using Different Bonding Systems in Class II Cavities

Objective: To evaluate the microleakage at the junction between amalgam-composite resin restorations using different bonding systems. Material and Methods: In this in-vitro study, standard class II cavities were prepared on 40 human maxillary premolars. The axial and gingival floor depths of the cavities were 2 mm and 1 mm below (cementoenamel junction), respectively. The samples were divided into 4 groups (n = 10). In all groups, a layer of 1-mm thick amalgam was used as a coating for the initial part of the gingival floor. In group 1, no bonding system was used for amalgam restoration. In group 2, G-Premio Bond was applied. G-Premio bond + alloy primer and single bond + alloy primer were used in group 3 and group 4, respectively. The rest of the cavities in all groups were then repaired using FiltekZ250 composite. The samples were thermocycled at 500 rpm and immersed in 1% methylene blue solution for 24 hours to allow dye penetration. Once cut, the samples were placed under a stereomicroscope (40X) to determine the microleakage rate. Data analysis was carried out using post-hoc and Chi-square tests (p<0.05). Results: The highest and lowest microleakage rate was related to groups 1 and 3, respectively. There was a significant difference between groups (1,2) and (1,3), and (1,4), and groups (2,3) (p<0.05). Conclusion: The use of alloy primer and bonding could reduce the microleakage between the two restorations

Comparison of the Effect Of 0.2% Chlorhexidine and Xylitol Plus 920 Ppm Fluoride Mouthwashes on Count of Salivary Streptococcus Mutants, a Pilot Study

Statement of the Problem: Dental caries is a common chronic disease. Mouthwashes and other preventive approaches play an important role in caries prevention. Finding the most efficient mouthwash in the market is always a concern for dentists and patients. Purpose: This study aimed to assess the effect of chlorhexidine (Behsa, Iran) and xylitol plus 920 ppm fluoride (FX) (Fuchs, Germany) mouthwash on salivary Streptococcus mutans (S. mutans), which is the main microorganism responsible for dental caries. Materials and Method: This single-blind randomized clinical trial was conducted on 30 dental students, divided into two groups. The salivary count of S. mutans was measured at the beginning of the study. Group 1 students used chlorhexidine mouthwash while group 2 used FX mouthwash for two weeks. Saliva samples were collected again and salivary count of S. mutans was determined. Data were analyzed using Mann Whitney and Wilcoxon signed rank tests Results: Salivary count of S.mutans significantly decreased in the two groups after using the mouthwashes (p 0.05). Conclusion: Within the limitations of this study, the results showed that both mouthwashes could decrease S. mutans count

Knowledge of adults about the symptoms and risk factors of oral cancer in Zanjan city

Objectives Oral cancer includes a wide range of malignant neoplasms and is one of the ten main causes of morbidity and mortality worldwide. This study aimed to assess the level of knowledge of adults about the symptoms and risk factors of oral cancer in Zanjan city. Methods This descriptive, cross-sectional study was conducted on 345 adults presenting to a teaching hospital in Zanjan in 2014. The data were collected using a questionnaire, which comprised of four main sections regarding symptoms and risk factors of cancer. The data were analysed using independent t-test and ANOVA. Results The mean score of knowledge of adults was 4.88 about the risk factors and 2.86 about the symptoms of cancer out of 12. No significant differences were noted in this regard between males and females or different age groups (P > 0.05). Level of knowledge was significantly correlated with the level of education (P < 0.05). Conclusion The score of knowledge of adults in Zanjan about the symptoms and risk factors of cancer was lower than the average required value in the community. It is absolutely necessary to enhance the public knowledge about oral cancer via the media

Effect of Staining Solutions and Repolishing on Composite Resin Color Change

Background and Aim : Success of composite restorations mainly depends on their color stability when in service. The present study aimed at assessing the effect of staining solutions and repolishing on composite resin color change .   Materials and Methods : In this experimental study, 200 specimens were fabricated with A2 and B2 shades of Spectrum (TPH, Dentsply) and Point 4 (Kerr, USA) composite resins (100 specimens each). Specimens were divided into 5 groups of 10 samples each and immersed in coffee, tea, coke, orange juice and distilled water for 30 days. Specimens were photographed with a digital camera (Fine Pix S9600). Color analysis was done with CS Photoshop software (CIE lab color space) at baseline, after color change and after repolishing. Obtained results were analyzed using Three-way ANOVA and LSD test. Level of significance was set at P<0.05 .   Results: All specimens showed a significant color change in all solutions except for water ( D E>3.3). The greatest color change occurred in B2 Spectrum composite resin in coffee while the smallest color change was observed in A2 Point 4 specimens in water. Except for water and coke, the difference in color change between the two composite resins in all solutions was statistically significant. Color changes of B2 shade were significantly higher than those of A2. Significant improvementswere observed in color of specimens after their repolishing. However, color change of specimens in coffee and tea did not improve to the clinically acceptable level by repolishing .    Conclusion : Color change of composite restorations depends on the type and shade of composite resin as well as patient’s nutritional habits