The aim of this prospective quantitative study was to compare the effect of different instructional formats on dental students' skills and knowledge acquisition for access cavity preparation. All first-year dental students were invited to participate in this study conducted during the four consecutive two-week endodontic rotation courses at the University of the Pacific Arthur A. Dugoni School of Dentistry in spring semester 2015. Four alphabetically distributed intact groups of students were randomly allocated to two groups (n=70 each) that participated in either small-group discussion or a traditional lecture on access preparation. The first outcome measure was skill acquisition, measured by the quality of access cavities prepared in extracted teeth at the conclusion of the session. Two blinded raters scored direct observations on a continuous scale. Knowledge, the second outcome measure, was scored with a multiple-choice and open-ended question test at the end of each two-week session. Data were obtained for 134 of the 140 students, for a 96% response rate. The results showed that students in the small-group discussion groups scored significantly higher than those in the lecture groups when skill performance was tested (p=8.9 x 10 -7 ). However, no significant differences were found in the acquisition of knowledge between the two groups on the written test. Active student participation was significantly related to improved manual skill acquisition, but the format of the session does not seem to have had a direct influence on acquired knowledge.Dr. Arias is Professor,

No abstract

No abstract

No abstract

The purpose of this study was to compare cyclic fatigue (CF) resistance of reciprocating instruments at body temperature and relate the findings to their martensitic transformation temperatures. Contemporary nickel-titanium (NiTi) reciprocating instruments WaveOne Primary, WaveOne Gold Primary and EdgeFile X1 (n = 20 each and #25 tip diameter) were tested for CF resistance at body temperature (37 AE 1°C). Instruments were actioned according to manufacturer guidelines until fracture occurred in a simulated canal (angle of curvature = 60°, radius of curvature = 3 mm and centre of curvature = 5 mm from the tip). Time to fracture was recorded, and data analysed using Weibull analysis. Two instruments of each were tested using differential scanning calorimetry (DSC) to assess phase transformation temperatures. Reciprocating instruments manufactured with new alloys seem to be safer to CF than those manufactured with traditional M-Wire at body temperature. Martensitic transformation temperatures seem not to relate with fatigue behaviour for reciprocating motions.