Students' Perspective on Undergraduate Research Experiences in Indonesian Dental Schools.

Undergraduate (UG) research is considered as an essential part of dental education. Numerous dental schools have included required course-based undergraduate research in their curricula. However, the implementation of UG research courses in the curriculum may vary between dental schools. In the present study, we aimed to evaluate student perspectives on UG research in the curriculum of Indonesian dental schools. A total of 203 participants from 10 dental schools returned the questionnaire. The participants were clinical students of the dentistry profession program who completed their undergraduate dentistry program from 2017 to 2022. The majority of study participants favored UG research in the curriculum of the undergraduate dentistry study program. Less than 20% participants perceived UG research experiments were not important in dental education. Factors that influenced these perceptions included the availability of adequate time to complete the course and sufficient support from research supervisors. Recommendations for improvement included providing an adequate time to complete UG research and adequate supervision to guide students to understand the conceptual background information of the research topics, designs, and scientific communication of data interpretation. Regular monitoring of students' performance and progress would ensure completion of UG research courses in a timely manner. In conclusion, although UG research as a compulsory course in the Indonesian dental curriculum was well received by the students, overcoming the challenges is essential for the improvement of the research environment for undergraduate dental students.

Local anesthetics inhibit muscarinic acetylcholine receptor-mediated calcium responses and the recruitment of ß-arrestin in HSY human parotid cells.

OBJECTIVES: Local anesthetics act on G protein-coupled receptors (GPCRs); thus, their potential as allosteric modulators of GPCRs has attracted attention. Intracellular signaling via GPCRs involves both G-protein- and ß-arrestin-mediated pathways. To determine the effects of local anesthetics on muscarinic acetylcholine receptors (mAChR), a family of GPCRs, we analyzed the effects of local anesthetics on mAChR-mediated Ca2+ responses and formation of receptor-ß-arrestin complexes in the HSY human parotid cell line. METHODS: Ca2+ responses were monitored by fura-2 spectrofluorimetry. Ligand-induced interactions between mAChR and ß-arrestin were examined using a ß-arrestin GPCR assay kit. RESULTS: Lidocaine reduced mAChR-mediated Ca2+ responses but did not change the intracellular Ca2+ concentration in non-stimulated cells. The membrane-impermeant lidocaine analog QX314 and procaine inhibited mAChR-mediated Ca2+ responses, with EC50 values of 48.0 and 20.4 µM, respectively, for 50 µM carbachol-stimulated Ca2+ responses. In the absence of extracellular Ca2+, the pretreatment of cells with QX314 reduced carbachol-induced Ca2+ release, indicating that QX314 reduced Ca2+ release from intracellular stores. Lidocaine and QX314 did not affect store-operated Ca2+ entry as they did not alter the thapsigargin-induced Ca2+ response. QX314 and procaine reduced the carbachol-mediated recruitment of ß-arrestin, and administration of procaine suppressed pilocarpine-induced salivary secretion in mice. CONCLUSION: Local anesthetics, including QX314, act on mAChR to reduce carbachol-induced Ca2+ release from intracellular stores and the recruitment of ß-arrestin. These findings support the notion that local anesthetics and their derivatives are starting points for the development of functional allosteric modulators of mAChR.

Muscarinic acetylcholine receptor-mediated phosphorylation of extracellular signal-regulated kinase in HSY salivary ductal cells involves distinct signaling pathways.

OBJECTIVES: Typical agonists of G protein-coupled receptors (GPCRs), including muscarinic acetylcholine receptors (mAChRs), activate both G-protein and ß-arrestin signaling systems, and are termed balanced agonists. In contrast, biased agonists selectively activate a single pathway, thereby offering therapeutic potential for the specific activation of that pathway. The mAChR agonists carbachol and pilocarpine are known to induce phosphorylation of extracellular signal-regulated kinase-1/2 (ERK1/2) via G-protein-dependent and -independent pathways, respectively. We investigated the involvement of ß-arrestin and its downstream mechanisms in the ERK1/2 phosphorylation induced by carbachol and pilocarpine in the human salivary ductal cell line, HSY cells. METHODS: HSY cells were stimulated with pilocarpine or carbachol, with or without various inhibitors. The cell lysates were analyzed by western blotting using the antibodies p44/p42MAPK and phosphor-p44/p42MAPK. RESULTS: Western blot analysis revealed that carbachol elicited greater stimulation of ERK1/2 phosphorylation compared to pilocarpine. ERK1/2 phosphorylation was inhibited by atropine and gefitinib, suggesting that mAChR activation induces transactivation of epidermal growth factor receptors (EGFR). Moreover, inhibition of carbachol-mediated ERK1/2 phosphorylation was achieved by GF-109203X (a PKC inhibitor), a ßARK1/GRK2 inhibitor, barbadin (a ß-arrestin inhibitor), pitstop 2 (a clathrin inhibitor), and dynole 34-2 (a dynamin inhibitor). In contrast, pilocarpine-mediated ERK1/2 phosphorylation was only inhibited by barbadin (a ß-arrestin inhibitor) and PP2 (a Src inhibitor). CONCLUSION: Carbachol activates both G-protein and ß-arrestin pathways, whereas pilocarpine exclusively activates the ß-arrestin pathway. Additionally, downstream of ß-arrestin, carbachol activates clathrin-dependent internalization, while pilocarpine activates Src.

Serious game as oral histology learning strategy for undergraduate dental students; crossover randomized controlled trial.

BACKGROUND: Oral histology is perceived by dental students as a challenging subject and often struggle to recognize the long-term relevance of understanding the cells and tissues at the microscopic level. Serious games have been reported to have a positive effect on student cognitive skills and learning motivation. However, there is still a limited amount of research supporting the effectiveness of serious games as a learning method in dentistry. The present study aimed to evaluate the impact of serious game of HistoRM as a complementary learning strategy for oral histology. METHODS: The study design was a crossover randomized controlled trial. A total of 74 first year dental students of Universitas Indonesia participated in the study and divided into 2 groups. Study intervention included HistoRM game for 3 days followed by a combination of HistoRM and script-based handouts for another 4 days. The groups represented different intervention sequences. Evaluation was performed using pre-test, post-test on day 3 and 7 and a questionnaire. RESULTS: The data showed significant improvement of student cognitive skills (p < 0.001) and it was influenced by the number of game missions completed. Students who completed the whole 15 missions have a higher day-7 post-tests scores (p = 0.03). Perception of dental students on HistoRM was positive in all domains tested, the learning content, games and learning experience domains. Immediate feedback given after each gameplay helped the students understand the subject matters. CONCLUSION: Serious game of HistoRM effectively improved students' understanding of oral histology learning outcome and provided more interesting learning experiences. This innovative learning can be recommended as a complementary learning strategy of oral histology for dental students.