RESUMO
AIM: To compare the frequency of misconceptions amongst dental students resulting from assessments in different subject areas using different types of multiple-choice questions (MCQs). We wanted to know whether misconceptions, or strongly held incorrect beliefs, differed by subject area or question type. METHODS: A total of 104 students completed two assessments that included 20 MCQs on endodontics and 20 MCQs on dental implants. On each examination, 10 questions were scenario-type questions requiring interpretation or analysis and 10 questions were factual-based, knowledge questions. Incorrect responses and confidence levels by student and subject were recorded for a comparison of average misconceptions by question type and for correlations between scenario and knowledge question types for misconceptions on both assessments. RESULTS: Students were overly confident on their incorrect responses and misconceptions for both assessments. On the endodontic examination, students held a statistically significant higher number of mean misconceptions on scenario questions than for knowledge questions, but the difference was not statistically significant for the dental implant examination. There was a moderately weak relationship between scenario and knowledge questions for misconceptions on the endodontic (r=.31) and dental implant (r=.20) assessments, suggesting students who have misconceptions on knowledge questions are somewhat more likely to have misconceptions on scenario questions. CONCLUSION: Students had a consistent rate of overconfidence (75%) in their incorrect responses regardless of question type or dental subject. Questions that prompted a higher per cent of incorrect responses were more likely to detect misconceptions, as students were highly confident in their mistakes, for both assessments.
Assuntos
Educação em Odontologia , Conhecimentos, Atitudes e Prática em Saúde , Autoeficácia , Estudantes de Odontologia/psicologia , Estudos Transversais , Feminino , Humanos , Masculino , AutorrelatoRESUMO
AIM: To assess the effect of bismuth oxide (Bi2 O3 ) on the chemical characterization and physical properties of White mineral trioxide aggregate (MTA) Angelus. METHODOLOGY: Commercially available White MTA Angelus and White MTA Angelus without Bi2 O3 provided by the manufacturer especially for this study were subjected to the following tests: Rietveld X-ray diffraction analysis (XRD), energy-dispersive X-ray analysis (EDX), scanning electron microscopy (SEM), compressive strength, Vickers microhardness test and setting time. Chemical analysis data were reported descriptively, and physical properties were expressed as means and standard deviations. Data were analysed using Student's t-test and Mann-Whitney U test (P = 0.05). RESULTS: Calcium silicate peaks were reduced in the diffractograms of both hydrated materials. Bismuth particles were found on the surface of White MTA Angelus, and a greater amount of particles characterized as calcium hydroxide was observed by visual examination on White MTA without Bi2 O3 . The material without Bi2 O3 had the shortest final setting time (38.33 min, P = 0.002), the highest Vickers microhardness mean value (72.35 MPa, P = 0.000) and similar compressive strength results (P = 0.329) when compared with the commercially available White MTA Angelus containing Bi2 O3 . CONCLUSION: The lack of Bi2 O3 was associated with an increase in Vickers microhardness, a reduction in final setting time, absence of Bi2 O3 peaks in diffractograms, as well as a large amount of calcium and a morphology characteristic of calcium hydroxide in EDX/SEM analysis.