In vivo real-time temperature measurement on the surface of intact and gold-restored teeth during consumption of hot and cold drinks.

This study aimed to measure real-time temperature changes in gold-restored teeth compared with intact teeth during the intake of hot and cold drinks. Sixteen molars, including eight natural intact teeth and eight restored teeth with gold inlays, were selected from the participants. Custom-made thermocouple sensors were attached to the coronal third of the buccal surface of teeth. Participants consecutively consumed hot and cold drinks according to a standardized regimen. Resting, maximum, and minimum temperatures; time to reach peak temperatures; and heating and cooling velocities were obtained. Statistical analysis was performed using independent two-sample t-test. Teeth with gold restorations showed a significantly higher maximum temperature (44.7 °C [SD 2.9]) than did natural teeth (40.5 °C [SD 1.2]) during hot water drinking and showed a lower minimum temperature (25.0 °C [SD 4.9]) than did natural teeth (31.5 °C [SD 3.1]) during cold water drinking. The heating and cooling rates for the teeth with gold restorations were two and three times higher than those of the natural teeth. Gold-restored teeth showed greater temperature change than intact teeth in terms of magnitude and velocity in response to temperature changes induced by hot and cold drinks.

Association between longitudinal tooth fractures and visual detection methods in diagnosis.

OBJECTIVES: This study investigated the distribution of longitudinal tooth fractures (LTFs) according to the patient's age and analyzed the association between visual detection methods and the types of LTFs. METHODS: Patients with symptomatic teeth with LTFs were examined at the department of conservative dentistry in a dental hospital from September 1, 2009 to March 31, 2014. Naked eye examination, staining with a dye, operating microscopy, transillunimation, and periapical radiography were used to identify the fracture lines. Diagnostic surgery was performed to visualize the fracture line in some cases with vertical root fractures. The final diagnosis was based on the American Association of Endodontists (AAE) classification: cracked tooth, fractured cusp, split tooth, and vertical root facture. The probability density function for each type of LTF was calculated to assess the risks of LTF development according to age. The association between the detection methods and types of LTFs was identified using the association plot. RESULTS: A total of 245 teeth with LTFs were enrolled. Overall, 71.8% of LTFs was observed in patients aged 40-69 years, and 65.7% of LTFs were diagnosed as cracked teeth. The mean age in patients with cracked teeth was 49.3 years, while the mean age in patients with fractured cusps was 59.1 years. A significant association was observed between the detection method and type of LTF (p < 0.001). CONCLUSIONS: Cracked tooth was the most common type of LTF. The probability of occurrence of cracked teeth peaked in patients aged approximately 50 years, while the probability of occurrence of fractured cusps peaked in patients aged approximately 60 years. Cracked teeth were detected most often using transillumination. CLINICAL SIGNIFICANCE: LTFs occurred mostly in patients aged 40 years and older. Transillumination is useful for the diagnosis of cracked teeth.

Cognitive Profiling Related to Cerebral Amyloid Beta Burden Using Machine Learning Approaches.

Background: Cerebral amyloid beta (Aß) is a hallmark of Alzheimer's disease (AD). Aß can be detected in vivo with amyloid imaging or cerebrospinal fluid assessments. However, these technologies can be both expensive and invasive, and their accessibility is limited in many clinical settings. Hence the current study aims to identify multivariate cost-efficient markers for Aß positivity among non-demented individuals using machine learning (ML) approaches. Methods: The relationship between cost-efficient candidate markers and Aß status was examined by analyzing 762 participants from the Alzheimer's Disease Neuroimaging Initiative-2 cohort at baseline visit (286 cognitively normal, 332 with mild cognitive impairment, and 144 with AD; mean age 73.2 years, range 55-90). Demographic variables (age, gender, education, and APOE status) and neuropsychological test scores were used as predictors in an ML algorithm. Cerebral Aß burden and Aß positivity were measured using 18F-florbetapir positron emission tomography images. The adaptive least absolute shrinkage and selection operator (LASSO) ML algorithm was implemented to identify cognitive performance and demographic variables and distinguish individuals from the population at high risk for cerebral Aß burden. For generalizability, results were further checked by randomly dividing the data into training sets and test sets and checking predictive performances by 10-fold cross-validation. Results: Out of neuropsychological predictors, visuospatial ability and episodic memory test results were consistently significant predictors for Aß positivity across subgroups with demographic variables and other cognitive measures considered. The adaptive LASSO model using out-of-sample classification could distinguish abnormal levels of Aß. The area under the curve of the receiver operating characteristic curve was 0.754 in the mild change group, 0.803 in the moderate change group, and 0.864 in the severe change group, respectively. Conclusion: Our results showed that the cost-efficient neuropsychological model with demographics could predict Aß positivity, suggesting a potential surrogate method for detecting Aß deposition non-invasively with clinical utility. More specifically, it could be a very brief screening tool in various settings to recruit participants with potential biomarker evidence of AD brain pathology. These identified individuals would be valuable participants in secondary prevention trials aimed at detecting an anti-amyloid drug effect in the non-demented population.

Do Dental Students' Personality Types and Group Dynamics Affect Their Performance in Problem-Based Learning?

The aim of this study was to determine whether the personality types of dental students and their group dynamics were linked to their problem-based learning (PBL) performance. The Myers-Briggs Type Indicator (MBTI) instrument was used with 263 dental students enrolled in Seoul National University School of Dentistry from 2011 to 2013; the students had participated in PBL in their first year. A four-session PBL setting was designed to analyze how individual personality types and the diversity of their small groups were associated with PBL performance. Overall, the results showed that the personality type of PBL performance that was the most prominent was Judging. As a group became more diverse with its different constituent personality characteristics, there was a tendency for the group to be higher ranked in terms of PBL performance. In particular, the overperforming group was clustered around three major profiles: Extraverted Intuitive Thinking Judging (ENTJ), Introverted Sensing Thinking Judging (ISTJ), and Extraverted Sensing Thinking Judging (ESTJ). Personality analysis would be beneficial for dental faculty members in order for them to understand the extent to which cooperative learning would work smoothly, especially when considering group personalities.

Does Reflective Learning with Feedback Improve Dental Students' Self-Perceived Competence in Clinical Preparedness?

The value of dental students' self-assessment is often debated. The aim of this study was to explore whether reflective learning with feedback enabled dental students to more accurately assess their self-perceived levels of preparedness on dental competencies. Over 16 weeks, all third- and fourth-year students at a dental school in the Republic of Korea took part in clinical rotations that incorporated reflective learning and feedback. Following this educational intervention, they were asked to assess their perceptions of their clinical competence. The results showed that the students reported feeling most confident about performing periodontal treatment (mean 7.1 on a ten-point scale) and least confident about providing orthodontic care (mean 5.6). The fourth-year students reported feeling more confident on all the competencies than the third-year students. Their self-perceived competence in periodontal treatment and oral medicine significantly predicted the instructors' clinical evaluations. This study offered insights into determining if structured reflective learning with effective feedback helps to increase dental students' self-perceived level of clinical preparedness.

Dentin wear after simulated toothbrushing with water, a liquid dentifrice or a standard toothpaste.

PURPOSE: To investigate the influence of dentifrices with and without abrasives on the wear and surface topography of human dentin following simulated toothbrushing in vitro. METHODS: 24 dentin specimens were prepared and randomly allocated to a liquid dentifrice (Garglin Gum-Guard), conventional dentifrice (333 Clinic Total Care), and control (distilled water) groups. Specimens were subjected to simulated toothbrushing of 50,000 repeated strokes under a 150 g-load. The dentin surface was profiled in each specimen using a profilometer before and after toothbrushing. The mean surface roughness (Ra) of the specimens was calculated and compared by one-way ANOVA and Tukey's post-hoc test (α = 0.05). The dentin surfaces were further examined by scanning electron microscopy (SEM). RESULTS: The Ra values were similar between the liquid dentifrice and control groups (P > 0.05), and was significantly higher in the conventional dentifrice group (P < 0.001). On SEM examination, patent dentin tubules were observed in the conventional dentifrice and liquid dentifrice groups, but were not observed in the control group.

[The relationship between dental graduate students' MBTI types and academic achievement in problem-based learning].

PURPOSE: The study aimed to determine the personality types of the graduate students in Seoul National University School of Dentistry (SNU SD) and analyze the specific personal types that were linked to their performance in problem-based learning (PBL). METHODS: A total of 263 graduate students in SNU SD from 2011 to 2013, participated in PBL and completed the Myers-Briggs Type Indicator (MBTI) GS form, which was analyzed statistically to determine whether their MBTI personality types were independent of their PBL performance. In particular, MBTI types were regressed on evaluation subcategories, including tutor evaluation and oral test. RESULTS: ESTJ (20.9%) and ISTJ (18.6%) were the most common MBTI personality types in dental graduate students. Compared with males, female students performed significantly better on the PBL. Judging was the most notable type in PBL performance, with its J-P index being statistically significant. CONCLUSION: PBL is implemented, based on the perspective of student-centered education. Accordingly, the types of personality that usually matriculate in dental school should be monitored, and a student-centered approach to dental education should be adopted.

Who succeeds at dental school? Factors predicting students' academic performance in a dental school in republic of Korea.

The purpose of this study was to examine what cognitive and non-cognitive factors were responsible for predicting the academic performance of dental students in a dental school in the Republic of Korea. This school is one of those in Korea that now require applicants to have a bachelor's degree. In terms of cognitive factors, students' undergraduate grade point average (GPA) and Dental Education Eligibility Test (DEET) scores were used, while surveys were conducted to evaluate four non-cognitive measures: locus of control, self-esteem, self-directed learning, and interpersonal skills. A total of 353 students matriculating at Seoul National University School of Dentistry in 2005, 2006, 2007, and 2008 consented to the collection of records and completed the surveys. The main finding was that applicants who scored higher on internal locus of control and self-efficacy were more likely to be academically successful dental students. Self-directed learning was significantly associated with students ranked in the top 50 percent in cumulative GPA. However, students' interpersonal skills were negatively related to their academic performance. In particular, students' lack of achievement could be predicted by monitoring their first-year GPA. Therefore, the identification of those factors to predict dental school performance has implications for the dental curriculum and effective pedagogy in dental education.

Transfer students' personality types and their academic performance in a graduate-entry dental school.

PURPOSE: The study was designed to identify how different types of transfer student personality would be constituted in Seoul National University School of Dentistry (SNU SD) and delve into what personal types were often observed more competent in academic performance. METHODS: Among 40 students who transferred to SNU SD in 2004, 15 students voluntarily participated in completing the Myers-Briggs type indicator (MBTI; GS form); then, it was tested whether or not their MBTI types would be dependent upon their final grades. In addition, another 32 out of the 50 students who were enrolled through a traditional pre-den system served as a control group. RESULTS: It was mainly found that ISTJ type was the most typical one for those transfer dental students as well as for other native dental students who excelled in their academic performance. The noticeable majority of transfer students were Introverted (67%), Sensing (80%), Thinking (86%), and Judging (80%), with S-J pattern being statistically significant. CONCLUSION: SNU SD has been in a rebuilding process in terms of student/outcome centered dental education to have it up to the global standards. For this reason, it is ultimately a crucial part of that process to understand what personality types of the dental students with different backgrounds in major are observed and thus recognize how to support their learning according to different patterns of individual personality.