Effect of smear clear and some other commonly used irrigants on dislodgement resistance of mineral trioxide aggregate to root dentin

This study aimed to assess the push-out bond strength of mineral trioxide aggregate (MTA) to root canal dentin after irrigation with Smear Clear in comparison with 2.5% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX) and saline as commonly used root canal irrigants. The coronal and mid-root areas of maxillary anterior teeth were horizontally sectioned into one-millimeter thick slices. The root canal lumen of dentinal slices was dilated using a diamond bur with 1.3 mm diameter. After the application of MTA, the samples were incubated in 100% humidity for 10 minutes and were then randomly divided into four groups (n=20) and immersed in Smear Clear, 2.5% NaOCl, 2% CHX and saline for 30 minutes. No irrigant was used for the control group (n=20). A wet cotton pellet was placed on the samples and after 48 hours of incubation, push-out bond strength was measured using a universal testing machine. The samples were evaluated under a stereomicroscope to determine the mode of failure. One-way ANOVA was used to assess statistical differences among the groups. The control group showed the highest bond strength with significant differences with other groups (P0.05). Other pairwise comparisons showed no significant difference (P>0.05). Irrigation with Smear Clear, CHX and NaOCl did not cause a significant change in bond strength of MTA to dentin

Moral skills of Iranian general dentists

Objective This study aimed to assess the moral skills of Iranian general dentists. Methods This cross-sectional study was performed on 384 general dentists selected in national congresses, in 2016. Volunteers were asked to fill out the moral skills inventory with four domains of integrity, courage, reasoning and sensitivity. Demographic factors were also assessed and their correlation with moral skills was evaluated using the backward linear regression model. Results The mean acquired score of sensitivity, reasoning, integrity and courage score was 2.96, 5.71, 4.11 and 4.50 out of 8, respectively and the mean percentage of total moral skills of dentists was 54%. Males and females were not significantly different in terms of scores acquired in the four domains (P > 0.05). The scores obtained in the four moral domains were higher in younger graduates (by increase in the graduation year) (P = 0.02). A significant inverse correlation was found between moral integrity and reasoning with father’s level of education (P < 0.05). The correlation between moral sensitivity and mother’s level of education did not reach statistical significance (P > 0.05). Conclusion The mean percentage of moral skills of Iranian dentists was moderate. Thus, especial emphasis should be placed on moral skills particularly moral sensitivity in medical ethics educational programs

Effect of Storage Time and Temperature on Dimensional Stability of Impressions Made with Zinc Oxide Impression Paste

Objectives: This study aimed to assess the effect of storage time and temperature on dimensional stability of impressions made with Cavex Outline zinc oxide impression paste. Materials and Methods: A round stainless steel mold with five grooves (three horizontal and two vertical) was used in this in-vitro experimental study. Cavex Outline impression paste was prepared according to the manufacturer’s instructions and applied to the mold. The mold was placed on a block and stored at 35°C and 100% humidity for setting. The impressions were poured with stone immediately and also after 30, 120, 240 and 420 minutes and 24 hours. The distance between the vertical lines on the casts was measured and compared with that in the immediately poured cast. Results: Storage in a refrigerator and at room temperature for zero to seven hours had no significant effect on dimensional stability of the impressions; however, 24 hours of storage in a refrigerator or at room temperature decreased the dimensional stability of Cavex Outline (P=0.001). Also, a significant association was found between dimensional changes following 24 hours of storage in a refrigerator (4°C) and at room temperature (23°C; P<0.01). Conclusions: The optimal pouring time of Cavex Outline impressions with stone is between zero to seven hours, and 24 hours of storage significantly decreases the dimensional stability.