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The aim of the present in vitro study was to evaluate the protective effect of self-assembling peptide P11-4 (Curodont™ Protect/Credentis) on enamel erosion produced by a soft-drink, by using Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). Thirty human incisors were equally and randomly assigned to 6 groups. Group 1: intact enamel, group 2: soft drink, group 3: Curodont™ Protect applied, group 4: Curodont™ Protect applied + soft drink, group 5: soft drink + Curodont™ Protect applied, group 6: soft drink + Curodont™ Protect applied + soft drink. Specimens were observed through atomic force microscopy (AFM). The root mean-square roughness (Rrms) was obtained from the AFM images and the differences in the averaged values among the groups were analyzed by Shapiro-Wilk test in order to assess the normality of the distribution. Parametric ANOVA and post hoc Tuckey test were performed to assess the differences between the different groups. After demineralization process, enamel demonstrated a high degree of surface porosity. This morphological aspect was reflected in the increase of Rrms values. No significant differences (p > 0.05) were reported between intact enamel and enamel only treated with P11-4 and between eroded enamel and enamel treated with P11-4 and then demineralized. However significant differences (p < 0.05) were recorded when comparing softened enamel with softened enamel further remineralized with biomimetic self-assembling peptides and enamel treated with the protective paste between two acid attacks. The use of P11-4 remineralizing may offer a degree of protection from enamel erosion. SCANNING 38:344-351, 2016. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of the present study was to investigate the cleaning efficacy of 2 different nickel-titanium (NiTi) rotary systems: a new single system Reciproc compared with the rotary full sequence Mtwo. The amount of debris and the morphology of smear layer were the parameters for the evaluation of the cleanliness of root canals. The null hypothesis of the study was that there would be no significant difference in debris scores and smear layer scores between the 2 systems. Methods: Forty single-rooted freshly extracted teeth were selected and divided into 2 groups. For each group, all root canals were shaped with 2 different NiTi instruments (Mtwo and Reciproc) and irrigated with 5.25% NaOCl and 17% ethylenediaminetetraacetic acid (EDTA) solutions by 3 trained operators. Specimens were fractured longitudinally and prepared for scanning electron microscopy (SEM) analysis at a standard magnification of ×5,000. The presence/absence of smear layer and the presence/absence of debris at the coronal, middle and apical third of each canal were evaluated using two 5-step scales for scores. Numeric data were analyzed using the Kruskal-Wallis and Mann-Whitney U statistical tests, and significance was set at a P value <0.05. Results: This study revealed significant differences among the various groups. The Mtwo group presented significantly lower smear layer scores than the Reciproc group (P<0.01) in the middle and apical third of the canal. Conclusions: Conventional continuous rotary NiTi instruments associated with 5.25% NaOCl and 17% EDTA solutions seem to be better for obtaining clean dentinal canal walls. Reciprocating instruments leave a higher quantity of smear layer which covers dentinal walls and dentinal tubules. [ABSTRACT FROM AUTHOR]