Introduction of integrated dental training jaw models and rubric criteria.

OBJECTIVE: The objective of the present study was to evaluate the effectiveness of introducing integrated jaw models, rubric criteria and homework tasks to a total clinical simulation training course to improve the clinical competence of preclinical dental students. METHODS: A total simulation training course, which involved six clinical dentistry departments, was held for 110 preclinical students in 2014 and 2015. We prepared integrated jaw models having several morbidities along with corresponding medical information and homework tasks. The students formulated diagnoses and devised treatment plans before performing dental treatment on the mannequin under the direction of instructors from the respective clinical departments. Their performance was assessed by both students and instructors using the rubric criteria. RESULTS: Based on quantitative evaluations, the introduction of integrated jaw models appeared to improve the students' ability to formulate diagnoses and devise dental treatment plans and to understand the respective clinical dentistry disciplines. The rubric criteria provided immediate feedback for the students. Based on a comparison of rubric scores, students tended to significantly underestimate their own performance compared with instructors. Moreover, the introduction of homework tasks improved student seriousness. CONCLUSION: Introducing integrated jaw models, rubric criteria and homework tasks to a total simulation training course may be a good approach for improving student performance in terms of dental diagnoses and treatment.

Quantification and identification of bacteria in acrylic resin dentures and dento-maxillary obturator-prostheses.

PURPOSE: To quantify and identify bacteria detected in acrylic resin dentures and dento-maxillary obturator-prostheses after long-term use. METHODS: The internal layer of denture bases from 13 daily-use removable acrylic resin dentures was sampled, while the inner fluid samples/no-fluid samples of obturators were collected from 11 in-use acrylic resin dento-maxillary obturator-prostheses. Samples were cultured, and isolated bacteria were counted and identified by molecular biological methods. RESULTS: Bacteria were detected in five (38.5%) acrylic resin dentures and six (54.5%) acrylic resin obturators. Four Lactobacillus species and one Propionibacterium species were isolated from three repaired denture bases, and from two non-repaired dentures, two Actinomyces species and Streptococcus mutans were isolated. On the other hand, 17 bacterial species, belonging to the family and genera of Olsenella, Bacillus, Citrobacter, Enterobacteriaceae, Lactobacillus, Pantoea, Peptoniphilus, Klebsiella and Pseudomonas, were isolated from obturators. Several species of viable bacteria were detected in acrylic resin denture bases and obturators.

Rapid quantification of bacteria in infected root canals using fluorescence reagents and a membrane filter: a pilot study on its clinical application to the evaluation of the outcomes of endodontic treatment.

Objective. The bacterial examination has been performed during the course of the root canal treatment. In the present pilot study, the new developed method, using fluorescence reagents and a membrane filter, was applied to the detection and quantification of bacteria in infected root canals, in order to evaluate the outcomes of the treatment. Methods. Six infected root canals with periapical lesions from 5 subjects were included. Informed consent was obtained from all subjects (age ranges, 23-79 years). Samples from infected root canals were collected at the beginning of the treatment (termed #25 First), the end of the first day of treatment (termed #55 First), and the next appointment day (termed #55 Second). Then, the bacterial count (CFU) was measured using fluorescence reagents (4',6'-diamidino-2-phenylindole and propidium iodide) and the polycarbonate membrane filter by Bioplorer. Results. The mean ± SD of CFU in the sample of "#25 First" was (1.0 ± 1.4) × 10(5). As the root canal treatment progressed, the CFU decreased as 7.9 × 10(3) (#55 First) and 4.3 × 10(2) (#55 Second). Conclusion. In the present pilot study, rapid detection and quantification of bacteria in infected root canals were found to be successfully performed using fluorescence reagents and a membrane filter (Bioplorer analysis).

Cultivable anaerobic microbiota of infected root canals.

Objective. Periapical periodontitis is an infectious and inflammatory disease of the periapical tissues caused by oral bacteria invading the root canal. In the present study, profiling of the microbiota in infected root canals was performed using anaerobic culture and molecular biological techniques for bacterial identification. Methods. Informed consent was obtained from all subjects (age ranges, 34-71 years). Nine infected root canals with periapical lesions from 7 subjects were included. Samples from infected root canals were collected, followed by anaerobic culture on CDC blood agar plates. After 7 days, colony forming units (CFU) were counted and isolated bacteria were identified by 16S rRNA gene sequencing. Results. The mean bacterial count (CFU) in root canals was (0.5 ± 1.1) × 10(6) (range 8.0 × 10(1)-3.1 × 10(6)), and anaerobic bacteria were predominant (89.8%). The predominant isolates were Olsenella (25.4%), Mogibacterium (17.7%), Pseudoramibacter (17.7%), Propionibacterium (11.9%) and Parvimonas (5.9%). Conclusion. The combination of anaerobic culture and molecular biological techniques makes it possible to analyze rapidly the microbiota in infected root canals. The overwhelming majority of the isolates from infected root canals were found to be anaerobic bacteria, suggesting that the environment in root canals is anaerobic and therefore support the growth of anaerobes.