Assessing the predictive validity of pre-admission criteria on dental students' academic performance: a cross-sectional study.

BACKGROUND: This study examines the multifaceted factors influencing academic performance among dental students in Saudi Arabia, exploring the complex relationships between demographic, educational, and psychological variables and students' Grade Point Averages (GPAs) to enhance global dental education admission strategies. METHODS: Data on demographics, academic performance indicators (including GPA, high school grades, test scores), accommodation type, parental education, suspension history, and English proficiency were collected through an English-language electronic questionnaire from 900 dental students across multiple institutions in Riyadh. The study employed Pearson's correlation analysis to examine relationships between GPA and various academic and demographic factors. A detailed regression analysis, using a stepwise selection based on Akaike's information criteria (AIC), identified significant GPA predictors and evaluated the average marginal effects of pre-admission variables on GPA, alongside rigorous diagnostic checks to validate the model's robustness. RESULTS: The study revealed a complex interplay of factors impacting GPA among dental students. High school grades, achievement, and aptitude test scores showed moderate positive correlations with GPA, while negative correlations were observed with age and number of times suspended. Regression analysis highlighted age, marital status, high school grades, and test scores as key predictors, with complex interaction effects demonstrating the layered influences of these factors. For instance, the negative impact of age on GPA was moderated by high school grade and aptitude test score. The analysis also highlighted the significant marginal effects of various pre-admission variables on GPA, such as the negative average impact of age and the positive impact of high school grades. CONCLUSIONS: This study provides valuable insights into the multifaceted determinants of academic success in dental education. Our findings underscore the significant roles of high school grades, achievement, and aptitude test scores, as well as the nuanced influence of age and marital status on GPA. These results advocate for a holistic approach in evaluating candidates for dental programs and have broader implications for global dental education, emphasizing the need for comprehensive admission strategies.

Evaluation of 2% Chlorhexidine and 2% Sodium Fluoride as Endodontic Irrigating Solutions on Root Dentine Microhardness: An In Vitro Study.

OBJECTIVES: The aim of this study was to evaluate the effects of 2% chlorhexidine gluconate (CHG) and 2% sodium fluoride (NaF) as endodontic irrigants on microhardness of root dentin. MATERIALS AND METHODS: In this in vitro study, access cavity and root canal preparations were done on 24 freshly extracted anterior teeth. After sectioning into 24 dentin discs using hard tissue microtome in 2 mm thickness, all samples were immersed in solutions of 17% ethylenediamine tetra-acetic acid (EDTA) (2 minutes) followed by 2.5% of sodium hypochlorite (NaOCl) (10 minutes). Then samples were randomly divided into three groups based on the irrigant used: Group I: saline (control group); Group II: 2% NaF; Group III: 2% CHG for two minutes each. Dentin microhardness was measured before (pretreatment), during (after treatment with 17% EDTA and 2.5% NaOCl), and after the experimental period (after treatment with saline, 2% NaF, and 2% CHG) using a Vickers indenter. Statistical evaluation of the data was done using one-way analysis of variance (ANOVA) and the Student's t-test, and the values are tabulated. RESULTS: Specimens rinsed in 2% CHG showed a significant increase in Vickers hardness number (VHN) values (p < 0.05), as compared with EDTA and NaOCl groups, whereas saline and 2% NaF groups showed no significant difference. CONCLUSIONS: NaF did not show any significant effect on microhardness of the root dentin. CHG as an irrigant was seen to have a strengthening effect on dentin microhardness in comparison to NaOCl and EDTA, which has decreased the strength of root dentin.