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.

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.

Impact of Undergraduate Research as a Compulsory Course in the Dentistry Study Program Universitas Indonesia.

Undergraduate (UG) research is regarded as a fundamental component in dental education. The present study was designed to examine the perception of the clinical students and the graduates of dentistry profession programs in the past 10 years on UG research as a compulsory course at the Faculty of Dentistry Universitas Indonesia. A total of 310 respondents, consisting of clinical students (64.8%) and alumni (35.2%), participated in this study. The majority of respondents (81.3%) agreed to UG research as part of compulsory courses in the curriculum of dentistry study programs. The positive impact of UG research on their professional careers was perceived by 78.3% of participants. Only 11.6% of participants responded that UG research experiments were not important in dental education, and 18.7% preferred UG research as an elective course. UG research as a compulsory course in the dental curriculum was well received by the majority of participants. Recommendations included student autonomy to select research topics of interest, longer duration to complete UG research, and more opportunities to present the research results in scientific conferences and to publish in scientific journals. Dental schools and their faculties play essential roles in improving the research environment for undergraduate dental students.

Student perspective of classroom and distance learning during COVID-19 pandemic in the undergraduate dental study program Universitas Indonesia.

BACKGROUND: The COVID-19 pandemic has become a global health issue and has had a major impact on education. Consequently, half way through the second semester of the academic year 2019/2020, learning methods were delivered through distance learning (DL). We aimed to evaluate the student perspective of DL compared to classroom learning (CL) in the undergraduate dentistry study program at the Faculty of Dentistry Universitas Indonesia. METHODS: An online questionnaire was sent at the end of the semester. A total of 301 students participated in the study. RESULTS: Duration of study influenced student preference. Higher number of first-year students preferred DL compared to their seniors (p < 0.001). Students preferred CL for group discussion, as DL resulted in more difficult communication and gave less learning satisfaction. Only 44.2% students preferred DL over CL, although they agreed that DL gave a more efficient learning method (52.6%), it provided more time to study (87.9%) and to review study materials (87.3%). Challenges during DL included external factors such as unstable internet connection, extra financial burden for the internet quota and internal factors such as time management and difficulty to focus while learning online for a longer period of time. CONCLUSION: Despite some challenges, dental students could adapt to the new learning methods of full DL and the majorities agreed blended learning that combined classroom and distance learning can be implemented henceforth. This current COVID-19 pandemic, changes not only the utilization of technology in education but the pedagogy strategies in the future.

Periodontal Ligament Cell Sheets and RGD-Modified Chitosan Improved Regeneration in the Horizontal Periodontal Defect Model.

OBJECTIVE: The aim of this study was to examine the potential of periodontal ligament (PDL) cells sheet and arginine-glycyl-aspartic acid (RGD)-modified chitosan scaffold for periodontal tissue regeneration in horizontal periodontal defect model. MATERIALS AND METHODS: PDL cell cytotoxicity was tested with 3-[4,5- dimethylthiazol-2yl]-2,5-diphenyl-2H-tetrazolium bromide assay. Cell migration toward the chitosan-based materials was analyzed with trans-well migration assay. Horizontal periodontal defect model was created in four maxillary and mandibular lateral incisors of Macaque nemestrina. Following periodontal therapy, the sites were transplanted with various regenerative materials: (1) chitosan, (2) RGD-modified chitosan, (3) PDL cell sheet with chitosan, (4) PDL cell sheet with RGD-modified chitosan. The periodontal tissue regeneration was evaluated clinically and radiographically. Gingival crevicular fluids were collected each week to evaluate cementum protein-1 (CEMP-1) expression with enzyme-linked immunosorbent assay, while the biopsies were retrieved after 4 weeks for histological and microcomputed tomography evaluation. STATISTICAL ANALYSIS: Data was statistically analyzed using GraphPad Prism 6 for MacOS X. Normality was tested using the Shapiro-Wilk normality test. The Kruskal-Wallis test was used to compare the groups. Significance was accepted when p < 0.05. RESULTS: Clinical examination revealed more epithelial attachment was formed in the group with PDL cell sheet with RGD-modified chitosan. Similarly, digital subtraction radiography analysis showed higher gray scale, an indication of higher alveolar bone density surrounded the transplanted area, as well as higher CEMP-1 protein expression in this group. The incorporation of RGD peptide to chitosan scaffold in the group with or without PDL cells sheet reduced the distance of cement-enamel junction to the alveolar bone crest; hence, more periodontal tissue formed. CONCLUSIONS: Horizontal periodontal defect model could be successfully created in M. nemestrina model. Combination of PDL cell sheet and RGD-modified chitosan resulted in the higher potential for periodontal tissue regeneration. The results of this study highlight the PDL cell sheet and RGD-modified chitosan as a promising approach for future clinical use in periodontal regeneration.

AI-2 of Aggregatibacter actinomycetemcomitans inhibits Candida albicans biofilm formation.

Aggregatibacter actinomycetemcomitans, a Gram-negative bacterium, and Candida albicans, a polymorphic fungus, are both commensals of the oral cavity but both are opportunistic pathogens that can cause oral diseases. A. actinomycetemcomitans produces a quorum-sensing molecule called autoinducer-2 (AI-2), synthesized by LuxS, that plays an important role in expression of virulence factors, in intra- but also in interspecies communication. The aim of this study was to investigate the role of AI-2 based signaling in the interactions between C. albicans and A. actinomycetemcomitans. A. actinomycetemcomitans adhered to C. albicans and inhibited biofilm formation by means of a molecule that was secreted during growth. C. albicans biofilm formation increased significantly when co-cultured with A. actinomycetemcomitans luxS, lacking AI-2 production. Addition of wild-type-derived spent medium or synthetic AI-2 to spent medium of the luxS strain, restored inhibition of C. albicans biofilm formation to wild-type levels. Addition of synthetic AI-2 significantly inhibited hypha formation of C. albicans possibly explaining the inhibition of biofilm formation. AI-2 of A. actinomycetemcomitans is synthesized by LuxS, accumulates during growth and inhibits C. albicans hypha- and biofilm formation. Identifying the molecular mechanisms underlying the interaction between bacteria and fungi may provide important insight into the balance within complex oral microbial communities.

Chitosan as a potential osteogenic factor compared with dexamethasone in cultured macaque dental pulp stromal cells.

Chitosan, a natural biopolymer derived from chitin, is considered a promising scaffold material for bone tissue engineering. The ability of chitosan to promote the osteogenic differentiation of dental pulp stromal/stem cells (DPSCs) is unknown. We have evaluated the potential of chitosan to induce the osteogenic differentiation of macaque DPSCs in comparison with that of dexamethasone. DPSCs were cultured in mineralizing medium supplemented with 5 or 10 µg/ml chitosan or with 1 or 10 nM dexamethasone. The metabolic activity of DPSCs was measured by MTT assay. Their osteogenic differentiation was determined by the number of transcripts of RUNX2, alkaline phosphatase (ALP), and COL1A1 by using real-time polymerase chain reaction, by alizarin red staining for mineral deposition, and by the ALP activity released into the medium for their ability to support biomineralizaton. Addition of chitosan to the mineralizing medium significantly increased DPSCs metabolism after 7 and 14 days of culture (P ≤ 0.0001). Chitosan at 5 µg/ml also significantly enhanced RUNX2 and ALP mRNA but not COL1A1 mRNA; chitosan tended to increase the release of ALP hydrolytic enzyme activity into the medium during the first week. Dexamethasone upregulated the osteogenic markers tested. Mineral deposition was similar in the chitosan and dexamethasone groups and was not statistically different from that of the mineralizing control group. Thus, the potential of chitosan to stimulate DPSCs proliferation and early osteogenic differentiation is comparable with that of dexamethasone, but mineralization remains unaffected by chitosan treatment. In addition to its role as a three-dimensional scaffold for osteogenic cells in vivo, chitosan might also stimulate DPSCs proliferation and early osteogenic differentiation in vitro.

Bone regeneration during distraction osteogenesis.

Bone has the capacity to regenerate in response to injury. During distraction osteogenesis, the renewal of bone is enhanced by gradual stretching of the soft connective tissues in the gap area between two separated bone segments. This procedure has received much clinical attention as a way to correct congenital growth retardation of bone tissue or to generate bone to fill skeletal defects. The process of bone regeneration involves a complex system of biological changes whereby mechanical stress is converted into a cascade of signals that activate cellular behavior resulting in (enhanced) formation of bone. Over the last decade, significant progress has been made in understanding the bone regeneration process during distraction osteogenesis. The mechanical and biological factors that are important for the success of the distraction treatment have been partially characterized and are discussed in this review.

Effect of thrombin peptide 508 (TP508) on bone healing during distraction osteogenesis in rabbit tibia.

Thrombin-related peptide 508 (TP508) accelerates bone regeneration during distraction osteogenesis (DO). We have examined the effect of TP508 on bone regeneration during DO by immunolocalization of Runx2 protein, a marker of osteoblast differentiation, and of osteopontin (OPN) and bone sialoprotein (BSP), two late markers of the osteoblast lineage. Distraction was performed in tibiae of rabbits over a period of 6 days. TP508 (30 or 300 microg) or vehicle was injected into the distraction gap at the beginning and end of the distraction period. Two weeks after active distraction, tissue samples were harvested and processed for immunohistochemical analysis. We also tested the in vitro effect of TP508 on Runx2 mRNA expression in osteoblast-like (MC3T3-E1) cells by polymerase chain reaction analysis. Runx2 and OPN protein were observed in preosteoblasts, osteoblasts, osteocytes of newly formed bone, blood vessel cells and many fibroblast-like cells of the soft connective tissue. Immunostaining for BSP was more restricted to osteoblasts and osteocytes. Significantly more Runx2- and OPN-expressing cells were seen in the group treated with 300 microg TP508 than in the control group injected with saline or with 30 microg TP508. However, TP508 failed to increase Runx2 mRNA levels significantly in MC3T3-E1 cells after 2-3 days of exposure. Our data suggest that TP508 enhances bone regeneration during DO by increasing the proportion of cells of the osteoblastic lineage. Clinically, TP508 may shorten the healing time during DO; this might be of benefit when bone regeneration is slow.

Immunolocalization of sibling and RUNX2 proteins during vertical distraction osteogenesis in the human mandible.

We tested the hypothesis that mechanical loading of human bone increases expression of the transcription factor RUNX2 and bone matrix proteins osteopontin (OPN), bone sialoprotein (BSP), dentin matrix protein-1 (DMP1), and matrix extracellular phosphoglycoprotein (MEPE). We examined this in tissue sections of atrophic mandibular bone taken from edentulous patients who had undergone distraction osteogenesis. In undistracted bone, weak to moderate staining for OPN and BSP was found in osteoblasts and bone matrix of immature woven bone. RUNX2 was also detectable in osteoblasts and in cells of the periosteum. In woven bone, but not in lamellar bone, a small number of osteocytes stained for all proteins tested. After distraction, staining intensity had increased in the existing old bone and staining was seen in more bone cells than before distraction. We also found a high expression of DMP1 and MEPE in many osteocytes embedded in woven bone and in some osteocytes of lamellar bone not seen before distraction. New bone trabeculae were forming in the fibrous tissue of the distraction gap containing all stages of intramembranous bone formation. Moderate to strong staining was seen for all five proteins tested in osteocytes located in woven bone of these trabeculae and for RUNX2, OPN, and BSP in osteoblasts lining the trabecular surfaces. We conclude that loading of atrophic human jawbone by distraction activates matrix synthesis of bone cells in and around existing bone. Increased staining of DMP1 and MEPE in osteocytes after loading is in line with the concept that these proteins may be involved in signaling the effector cells to adapt the bone structure to its mechanical demands.

Formation of new bone during vertical distraction osteogenesis of the human mandible is related to the presence of blood vessels.

We examined the effect of distraction rate on blood vessel growth in intramembraneous ossification after vertical distraction osteogenesis in the human mandible. Six edentulous patients (aged 60+/-9 years) with a severely atrophic mandible underwent bone augmentation with distraction osteogenesis. Two distraction rates (0.5 and 1 mm/day) were compared and for each group three patients were analyzed. Vascular histomorphometry was carried out in two different areas in the distraction gap: (1) in the first and (2) in the second 1 mm area from the osteotomy line, representing the oldest and younger new-bone area, respectively. Correlation analysis was performed between blood vessel parameters and the amount of new bone formed during distraction. Histological analysis demonstrated the presence of blood vessels throughout the soft connective tissue in the distraction gap. The volume density of blood vessels between the two investigated areas was significantly lower in the 1 mm/day groups, suggesting a delay in angiogenesis in this group of patients. A positive correlation between blood vessel volume and bone volume density was found in the younger new-bone area but not in the oldest new-bone area. This correlation was due to a higher number of blood vessels rather than to a larger size of the blood vessels. Our data suggest that the lower blood vessel density found in the patients with 1 mm/day distraction rate may be related to disruption of angiogenesis in the soft connective tissue of the gap or to a less optimal mechanical stimulation of cells involved in angiogenesis. This probably results in the slower rate of osteogenesis seen at the 1 mm/day distraction rate compared with the 0.5 mm/day distraction rate. The data support the concept that a positive relationship exists between the density of blood vessels and the formation of bone. For distraction of the human mandible in elderly patients, a distraction rate of 0.5 mm/day seems beneficial.

Vertical distraction osteogenesis in the human mandible: a prospective morphometric study.

Vertical distraction osteogenesis has received considerable interest as a way to augment bone prior to implant placement. However, very little is known regarding the appropriate distraction protocols in the human mandible. In this study, we evaluate the effect of the distraction rate and the duration of neutrofixation on bone formation and closure of the gap in the human mandible. Vertical distraction was performed in the atrophic mandible of 16 edentulous patients, aged 62+/-6 years. The bone was distracted for approximately 10 mm at a rate of either 0.5 or 1 mm/day. Bone biopsies were taken after 7-20 weeks of neutrofixation. Histological analysis demonstrated newly formed bone in the distraction gap in all biopsies. The bone was predominantly of the woven type. After 10 weeks of neutrofixation, the gap was bridged by new bone in two out of three intact samples in the 0.5 mm/day group, but not in two intact samples of the 1 mm/day group. Histomorphometry revealed longer bone trabeculae (P=0.02) and a somewhat increased bone volume in the area where new bone formation started (P=0.07) in the group of patients having the 0.5 mm/day of distraction rate than in the 1 mm/day group. We conclude that in elderly patients, a distraction rate of 0.5 mm/day results in faster osteogenesis in the distraction gap than a rate of 1 mm/day. A minimum of 10 weeks of neutrofixation seems to be needed to close a 10 mm gap after cessation of distraction.