RESUMEN
STATEMENT OF THE PROBLEM: Examinations have an important role in evaluating students' learning outcomes and their mastery of a subject. Passing or failing an examination can have far-reaching consequences for the students. Therefore, it is not surprising that international studies consistently show that dental students report examinations and grades among the highest ranking stressors in dental schools. PURPOSE: The aim of this research was to measure the levels of anxiety, self-perception of preparation and expectations for success using an objective structured clinical examination (OSCE), a written examination and a preclinical preparation test, and to examine the effects of the three predictive variables on the outcomes of assessments. MATERIALS AND METHODS: The present research is a cross-sectional study. The population under consideration was students of Kerman Dental School in 2013. Examination anxiety was measured with Spielberger's state anxiety inventory. Preparation for the assessment (I am fully prepared = 4, I am prepared = 3, I'm not prepared = 2, I'm not fully prepared = 1) and expectation to succeed (I am quite successful = 4, I am successful = 3, I'm not successful = 2, I'm not quite successful = 1) were quantified with Likert scale. The questionnaire was completed during an OSCE, a written examination, a preclinical crown and bridge preparation test and a nonexamination situation. RESULTS: The study population consisted of 138 4th, 5th, and 6th year Kerman dental students (65 males and 73 females). The results showed that all the assessment methods induced a significant increase in state anxiety compared to baseline levels with the highest anxiety levels reported during an OSCE (62.4 ± 8.1, P = 0.04) and a written examination (48.8 ± 9.2, P = 0.04). The preparation levels in females were significantly higher than those in males in OSCE (P = 0.03) and written (P = 0.04). CONCLUSION: State anxiety was high in all the three assessment methods. OSCE induced more anxiety than other assessment formats. However, anxiety was not predictive of performance outcomes in contrast to preparation and expectation to succeed, which were good predictors of the outcome scores. Also, this study showed that despite a better answer to the assessment of (I prepared myself well for the test), the students showed high levels of state anxiety.
RESUMEN
BACKGROUND: It is known that dental unit waterline can be a source of infection. The aim of this study was to evaluate the efficacy of a mouthwash, chlorhexidine, in controlling microbial and fungal contamination of dental unit waterlines. MATERIALS AND METHODS: In the present experimental study, the water in high-speed handpieces and air/water syringes of 35 dental units in a dental school was investigated microbiologically. Five of the units and one tap water served as controls; 100-200-mL water samples were collected aseptically in sterile containers in the morning after a 2-min purge. Water reservoir bottles were emptied and 50 mL of 0.2% chlorhexidine mouthwash was introduced into the tank. Then the water syringe was used to flush the waterline until the pink-colored chlorhexidine was observed to flow from the water syringe. Before the next day's session and before the students used the unit, two water samples from the water syringe and water turbine was collected. The samples were transferred to the laboratory. After 48 h at 37°C, the microbial colonies were counted. The number of these colonies was evaluated using colony forming unit CFU. Data were analyzed with Mann - Whitney U test and SPSS 13.5 statistical program. The statistical significance was defined at P ≤ 0.05. RESULTS: All 35 units were contaminated before chlorhexidine use; no contamination was detected after adding chlorhexidine to the waterlines of the units. After week 1, 28 of the 30 treated dental unit waterlines (DUWLs) had values of CFU/mL less than 200. CONCLUSION: The present study showed that the use of chlorhexidine could reduce microbial counts in dental unit waterlines.