Micro-CT evaluation of sonically and ultrasonically activated irrigation on the removal of hard-tissue debris from isthmus-containing mesial root canal systems of mandibular molars.

AIM: To evaluate the efficacy of sonically and ultrasonically activated irrigation on removal of accumulated hard-tissue debris (AHTD) in mesial root canal systems of mandibular molars using micro-computed tomographic (micro-CT) analysis. METHODOLOGY: Forty mesial roots of mandibular molars with two independent canals joined apically by an isthmus (Vertucci type II) were selected. The root canals were instrumented using Reciproc R25 instruments, and specimens were scanned at a resolution of 10.5 µm. Subsequently, n = 10 roots were assigned to each of the four final irrigation groups such that the group means and variances were almost identical: sonically activated irrigation with EndoActivator (EA) or EDDY (ED), ultrasonically activated irrigation (UAI) and manual irrigation without activation (MI). The final irrigation procedures were performed using a total of 5 mL 1% NaOCl and 5 mL 15% EDTA per canal over 5 min with activation time of 4 × 20 s. Reconstructed data sets were coregistered, and the mean percentage reduction of AHTD after final irrigation was compared statistically between groups using analysis of variance at a significance level set at 5%. RESULTS: A significant reduction of AHTD was achieved after final irrigation in all groups (P < 0.05), ranging from 44.1% to 66.8%. The vol% of debris after irrigation was 3.7 ± 1.9% for EA, 3.3 ± 2.3% for ED, 2.1 ± 1.6% for UAI and 4.4 ± 2.3% for MI, with no significant difference between groups (P > 0.05). CONCLUSIONS: None of the final irrigation protocols completely removed AHTD from mesial root canal systems in extracted human mandibular molars. Sonically and ultrasonically activated irrigation performed no better compared to manual irrigation.

The psychology of the withdrawal process: a cross-validational test of Mobley's intermediate linkages model of turnover in two samples.

A study investigating the validity of Mobley's (1977) model of the intermediate linkages in the turnover decision process among employees working in two diverse settings yielded a pattern of results generally consistent with the model. However, except for commitment to the organization, regression analyses failed to double cross-validate either within or between samples.

Relationship between self-confidence and sex role identity among managerial women and men.

The self-confidence and sex role identities of 437 American female and male managers were examined by using three subscales of the Adjective Check List. Results showed that, contrary to stereotypes and older research, female and male managers were strikingly similar. Women and men with cross-sex role identities showed lower levels of self-confidence than those did with androgynous orientations; high self-confidence was linked with masculine and androgynous orientations. The managers were not significantly different in self-confidence when demographic variables and sex role identity were held constant. Sex role identity (but not gender) was a major factor in the level of self-confidence.

Development and validation of the sex role conflict scale.

Because the authors found previous attempts at measuring sex role conflict to lack rigor in measurement and interpretation, they sought to develop an instrument for objectively measuring this condition. From a study of an initial group of 102 persons and a follow-up group of 556 persons from Western U.S. urban areas, the authors developed a new, 17-item, Likert-type scale, which they call the Sex Role Conflict Scale (SRCS). They employed factor analysis to arrive at the final 17 items used, and conducted studies of the scale's reliability and validity, correlating its results with previously validated measures of role conflict, job satisfaction, job involvement, and propensity to leave. The authors found correlations between their variables and sex role conflict, and recommend the SRCS for measuring the degree of such conflict experienced by both men and women.