Job shadowing for early undergraduate dental students: Evaluation and validation of educational effectiveness using structural equation modelling.

INTRODUCTION: This study aimed to evaluate and validate the educational effectiveness of a job shadowing class as a dental teaching programme for preclinical dental students through a questionnaire that assessed related student perceptions. MATERIALS AND METHODS: A total of 124 preclinical (second year) dental students at Tokushima University participated in job shadowing placements from 2017 to 2019. Each student observed dental practice or surgery for 1 day in the university hospital. After shadowing, the students were requested to fill out a nine-item questionnaire based on a five-point scale. The first analysis was performed to calculate the correlation for each item. Furthermore, regression analysis for the categorical data was performed to show the relationship between eight questions (Items 1-8) and one question (Item 9: comprehensive evaluation). Next, factor analysis was performed to determine students' perceptions regarding the shadowing class. RESULTS: Ninety-eight students (response rate: 79%) completed the questionnaire. There was a strong relationship amongst Items 1, 8 and 9 ("interested in dentistry as a job," "learning motivation" and "comprehensive evaluation" respectively) based on the results of the correlation and regression analysis. The factor analysis led to three student perceptions as latent factors, namely, "Interesting," "Self-awareness" and "Future Goal," which had a relatively close inter-factor correlation (0.465-0.772). CONCLUSION: The finding suggests that job shadowing may increase a students' interest in a dentistry career at an early stage of their education and learning motivation, along with generating self-awareness. This programme may present possible educational effectiveness in dental education.

Transgenic overexpression of gremlin results in developmental defects in enamel and dentin in mice.

Bone morphogenetic proteins (BMPs) and BMP antagonists play a crucial role in the regulation of tooth development. One of the BMP extracellular antagonists, gremlin, is a highly conserved 20.7-kDa glycoprotein. Previously, researchers reported that transgenic mice overexpressing gremlin under the control of the osteocalcin promoter (gremlin OE) exhibit a skeletal phenotype and tooth fragility. To further define the tooth phenotype, teeth and surrounding supporting tissues, obtained from gremlin OE at ages of 4 weeks, 2 months, and 4 months, were examined. The histological results demonstrate that gremlin OE exhibit an enlarged pulp chamber with ectopic calcification and thinner dentin and enamel compared with wild-type control. In vitro studies using murine pulp cells revealed that gremlin inhibited BMP-4 mediated induction of Dspp. These data provide evidence that balanced interactions between BMP agonists/antagonists are required for proper development of teeth and surrounding tissues. It is clear that these interactions require further investigation to better define the mechanisms controlling tooth root formation (pulp, dentin, cementum, and surrounding tissue) to provide the information needed to successfully regenerate these tissues.