Effects of the exposure site on histological pulpal responses after direct capping with 2 calcium-silicate based cements in a rat model

OBJECTIVES: Direct pulp capping is a treatment for mechanically exposed pulp in which a biocompatible capping material is used to preserve pulpal vitality. Biocompatibility tests in animal studies have used a variety of experimental protocols, particularly with regard to the exposure site. In this study, pulp exposure on the occlusal and mesial surfaces of molar teeth was investigated in a rat model. MATERIALS AND METHODS: A total of 58 maxillary first molars of Wistar rats were used. Forty molars were mechanically exposed and randomly assigned according to 3 factors: 1) the exposure site (occlusal or mesial), 2) the pulp-capping material (ProRoot White MTA or Bio-MA), and 3) 2 follow-up periods (1 day or 7 days) (n = 5 each). The pulp of 6 intact molars served as negative controls. The pulp of 12 molars was exposed without a capping material (n = 3 per exposure site for each period) and served as positive controls. Inflammatory cell infiltration and reparative dentin formation were histologically evaluated at 1 and 7 days using grading scores. RESULTS: At 1 day, localized mild inflammation was detected in most teeth in all experimental groups. At 7 days, continuous/discontinuous calcified bridges were formed at exposure sites with no or few inflammatory cells. No significant differences in pulpal response according to the exposure site or calcium-silicate cement were observed. CONCLUSIONS: The location of the exposure site had no effect on rat pulpal healing. However, mesial exposures could be performed easily, with more consistent results. The pulpal responses were not significantly different between the 2 capping materials.

Interdisciplinary and inter-institutional differences in learning preferences among Malaysian medical and health sciences students

Introduction: The learner-centered approach in medical and health sciences education makes the study of learning preferences relevant and important. This study aimed to investigate the interdisciplinary, interinstitutional, gender and racial differences in the preferred learning styles among Malaysian medical and health sciences students in three Malaysian universities, namely SEGi University [SEGi], University of Malaya [UM] and Universiti Tunku Abdul Rahman [UTAR]. It also investigated the differences in the preferred learning styles of these students between high achievers and non-high achievers

Methods: This cross-sectional study was carried out on medical and health sciences students from three Malaysian universities following the approval of the Research and Ethics Committee, SEGi University. Purposive sampling was used and the preferred learning styles were assessed using the VARK questionnaire. The questionnaire was validated prior to its use. Three disciplines [medicine, pharmacy and dentistry] were chosen based on their entry criteria and some similarities in their course structure. The three participating universities were Malaysian universities with a home-grown undergraduate entry medical program and students from a diverse cultural and socioeconomic background. The data were analysed using the Statistical Package for the Social Sciences [SPSS] software, version 22. VARK subscale scores were expressed as mean +/- standard deviation. Comparisons of the means were carried out using t-test or ANOVA. A p value of

Results: Both statistically significant interdisciplinary and inter-institutional differences in learning preferences were observed. Out of the 337 students, a majority of the participants were unimodal learners [n=263, 78.04%]. The most common type of learners was the reading/writing type [n=92, 27.30%] while the kinesthetic subscale [M=6.98, SD=2.85] had the highest mean score. Female students [M=6.86, SD=2.86] scored significantly higher than male students [M=6.08, SD=2.41; t[249], p=0.014] in the auditory subscale, whereas Chinese students [M=5.87, SD=2.65] scored significantly higher than Malay students [M=4.70, SD=2.87; p=0.04] in the visual subscale. However, the mean VARK subscale scores did not differ significantly between high achievers and non-high achievers [p>0.05]

Conclusion: This study gives an insight into the learner characteristics of more than one medical school in Malaysia. Such multi-institutional studies are lacking in the published literature and this study gives a better representation of the current situation in the learning preferences among medical students in Malaysia

Bacillus Thuringiensis Parasporal Proteins And Their Effect On Human Cancer Cells : An Overview

Bacillus thuringiensis is an anaerobic, spore forming bacterium that produces various toxic proteins both during its vegetative stage and sporulative stage. During its sporulative stage, it produces parasporal proteins that have long been used in the agriculture fields as insecticides. Although anticancer effect of Bacillus thuringiensis parasporal proteins can be dated back to the 1970s, research in this area went through a giant leap in the late 1990s, with much of the work being done in Japan. It has been found that some strains of non-insecticidal Bacillus thuringiensis produce parasporal proteins that exhibit anticancer activity. Due to their selectivity against human cancer cells but not normal cells, some of these proteins have been extensively studied for their anticancer effect and the mechanism of action by which these proteins kill cancer cells have also been widely explored in Japan and Malaysia with sporadic reports from other parts of the world. The abundance of these bacilli in nature and their selectivity have made them potential candidates for cancer treatment. However, literature on the in vivo effect of these proteins is scarce. Since different Bacillus thuringiensis strains produce different cytotoxic proteins with wide variations in their anticancer effect and mechanism of action, further investigations are necessary and their effect in vivo must be well established before they can be used in human subjects.