The aim of this pilot study was to evaluate the shear bond strength of superficial bovine incisor dentin in different crown regions. Bonding was performed to the incisal, middle and cervical thirds of superficial bovine coronal dentin (n = 20) with a two-step etch-and-rinse adhesive (Optibond Solo Plus) and resin composite (Z100). Shear bond strength was evaluated at 24 h and failure modes of representative specimens wereobserved with FE-SEM. Non-parametric Kruskal-Wallis test with a significance level of 0.05 was used for data analysis. Mean shear bond strength values for the incisal, middle, and cervical thirds were 36.9 (3.1), 42.6 (2.6), and 37.1 (2.1) respectively with no significant differences evidenced between the crown thirds (p = 0.19). Observation of the failure mode of representative specimens demonstrated that specimens with high bond strength values exhibited predominantly mixed-type failures whereas low strength specimens exhibited adhesive failures between the dentin and adhesive. The absence of significant differences in shear bond strength between crown thirds indicate that, regardless of tubule orientation, any crown region can be used when superficial bovine incisor dentin is used for shear bond strength testing.
The effect of different types of surface preparation
with SiC abrasive paper on the shear bond strength (SBS) of superficial
bovine dentin obtained from the incisal, middle and cervical thirds were
evaluated. Dentin substrates were obtained with twenty specimens for each
locationgrit combination. Superficial dentin was exposed and prepared to 120-, 320-, or 600-grit SiC; the
dentin surfaces were treated with Optibond Solo Plus (Kerr) and polymerized
for 20 s. The specimens were
placed in a jig, filled with resin composite Z100 (3M-ESPE), polymerized for 40
s according to manufacturer’s
instructions, and stored for 24 h at 37℃ and 100% humidity. After 24 h, SBS was measured using a
loading testing machine (Ul-tradent) and expressed in megapascals. A two-way
ANOVA and Tukey test were used for data analysis. No statistically significant effect of the location (P = 0.254) or interaction
grit-location (P = 0.629) were observed on SBS. Statistically
significant effect of the grit on the SBS was detected (P < 0.001) with
320-grit being statistically different from 600-grit (P = 0.011) and 120-grit
(P < 0.001). No significant differences were observed between 600-grit and
120-grit (P = 0.413). Regardless of the location, 320-grit consistently
showed the lowest SBS indicating that different surface grit preparations have
an effect on dentin SBS values.
Objective: The aim of this study was to evaluate the efficacy of a new Professionalism curriculum in an Obstetrics and Gynecology (OB/GYN) residency after introducing Narrative Medicine and Professional Development/Support Group (PDSG) programs. Methods: 32 OB/GYN residents participated in this IRB approved pilot study. Twenty residents were assessed with the Barry Challenges to Professionalism Questionnaire (Barry), the Jefferson Scale of Empathy-Physician Version (JSE), and the Jefferson Scale of Attitudes Toward Physician-Nurse Collaboration (JSAT) in August 2010, as controls. Five Narrative Medicine sessions and four PDSG sessions were then used from August 2010-May 2011, for resident physician professionalism education. Seventeen residents then underwent post-testing with the Barry, JSE, and JSAT in May 2011. Results: The pre-test/post-test Barry comparison showed an improvement in scores after introduction of the new Narrative Medicine and PDSG curriculum (7.6 +/- 2.1 versus 8.4 +/- 1.6; p = 0.10) though this was not statistically significant. Pre-test/post-test comparison of JSAT scores showed a statistically significant decline in collaboration (52.3 +/- 4.1 versus 49.7 +/- 3.7; p = 0.028) while JSE scores showed a downward trend in empathy (109.3 +/- 10.0 versus 104.8 +/- 9.2; p = 0.086). Conclusion: Narrative Medicine and PDSG small group sessions could be an effective component of OB/GYN resident physician Professionalism curriculum. This pilot project was underpowered, due to limited resources.