Introduction: Mouthwashes which prevent and control caries and periodontal diseases are commonly used even without professional prescription. Long-term use of mouthwashes may cause softening of restorative composites and lowering the longevity of restoration. The aim of this study was evaluation of surface hardness value of a microhybride composite (Filtek Z250) after 12 hours immersion in three kinds of alcohol-free mouthwashes. Materials and Methods: 72 Cylinderical specimens of a microhybride composite 5mm wide were prepared, using drinking straw as a mold. Specimens were light-cured continuously for 40 seconds on each side with Elipar(3M,ESPE) curing light. The specimens were immersed in 50ml of distilled water for12 hours. After that, all of them were finished with silicone carbide papers under constant water as coolant. The specimens were divided into 4 groups, each with 18 samples, the first group immersed in Colgate plax , the second in Crest (pro-health for me) , group3 in OraCare and group4 in water as the control group for 12 hours, which is equivalent to 1 year of daily mouthwash use at 2 minutes per day. Hardness measurement was taken by Vickers hardness tester with 1 kilogram load and 10 seconds loading time. Result: Statistical analysis according to t-test and One-Way ANOVA test showed that there was no significant difference in surface hardness value of composite after 12 hours immersion between groups of mouthwashes and water(P value=0.353) Conclusion: Based on the present study, alcohol-free mouthwashes didn't affect the surface hardness of Filtek(Z250) composite.
Introduction:The exact measurement of the root canal length is of great importance in root canal therapy. Although determination of the root canal length through radiography is the most common method, recently electronic apex locators have been used to determine working length and decrease the number of radiographs. The purpose of this study was to compare the accuracy of an electronic apex locator (Root ZX) with conventional radiography to determine the working length (WL) of curved mandibular molars.
Materials and methods:Thirty-five intact mandibular first molars with curve above 10 0 were selected. The access cavity was prepared and the root canal length was measured using apex locator and conventional radiography. Data were analyzed using the paired-sample t-test.
Results:The working lengths measured by the apex locator were equal to the actual working lengths in 42.86%, 0.5-1 mm shorter in 31.43%, and 0.5 mm longer in 25.71%. The working lengths measured by radiography were equal to the actual working length in 51.14%, 0.5-1 mm shorter in 39.99%, and 0.5 mm longer in 2.86%. There was no significant difference between these two methods in the measurement of the working length (p = 0.951).
Conclusion:The apex locator and conventional radiography were equally effective in determining the working length of the curved canals.
Infection control procedures are essential for dentists. Oral and dental impressions can act as carriers of contaminants that can increase the risk of infections while being transferred from the laboratory to the dental office. Therefore, the aim of this study was to evaluate the knowledge and practice of dentists regarding disinfection of impressions sent to the laboratory. Materials and methods: In this sectional descriptive study, 166 dentists in Rasht were randomly surveyed using a questionnaire that included routine demographic questions, including 10 on knowledge and 15 on practice. Each correct answer was scored +1 in the two-choice questions, and each choice was graded as weak, moderate, or good in the multiple-choice questions. Chi-square and Wilcoxon-Mann-Whitney tests were performed using SPSS 19.0 software to analyze the data. Results: The total mean and standard deviation values for dentists' knowledge were found to be 2.11 ± 0.562, and 18 (10.8%), 112 (67.5%), and 36 (21.7%) of the 166 dentists demonstrated good, moderate, and weak knowledge, respectively. The total mean and standard deviation values for dentists' practice were 1.67 ± 0.663, and 72 (43.4%), 76 (45.8%), and 18 (10.8%) dentists demonstrated good, moderate, and weak practice, respectively. Conclusion:Most dentists demonstrated moderate knowledge and practice of disinfection of dental impressions, and in many cases, the knowledge was not commensurate with the practice. Thus, despite the moderate and upward knowledge, the practice was weak. Furthermore, the dentists' knowledge and practice were not sufficient to ensure disinfection of impressions. Better training and careful monitoring is needed in this regard.
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