Mahmoud M. Bakr

Foreign body giant cells and osteoclasts are TRAP positive, have podosome‐belts and both require OC‐STAMP for cell fusion

Macrophages have the ability to fuse and form multinucleated giant cells such as Osteoclast (OCs) and FBGCs. Osteoclast stimulatory transmembrane protein (OC‐STAMP) is an important cell surface protein involved in the formation of OCs. This study sought to determine if OC‐STAMP also regulates formation of FBGCs using expression analysis and subsequent inhibition studies. qPCR and Western blot analysis showed that OC‐STAMP expression is significantly higher in FBGCs compared to control monocytes (P < 0.05). Four days following cell culture, OCs were positive for TRAP and F‐actin ring formation, but FBGCs were not. In contrast, FBGCs were positive for TRAP and showed podosome belts comprised of F‐actin on Day 8. FBGCs were subsequently plated onto dentine, but despite presenting some morphologic features of OCs (OC‐STAMP expression, TRAP reactivity, and podosome belts) they failed to resorb bone. To evaluate a role for OC‐STAMP in FBGCs, we inhibited this cell surface protein with anti‐OC‐STAMP antibody and observed that cell fusion and podosome belt formation was inhibited in both OCs and FBGCs. Our data support the hypothesis that OC‐STAMP is a regulatory molecule for FBGCs; and that they are functionally distinct from OCs, despite similarities in gene expression profile, podosome belt formation, and TRAP expression. J. Cell. Biochem. 114: 1772–1778, 2013.

Differential Expression of Chemokines, Chemokine Receptors and Proteinases by Foreign Body Giant Cells (FBGCs) and Osteoclasts

Osteoclasts and foreign body giant cells (FBGCs) are both derived from the fusion of macropahges. These cells are seen in close proximity during foreign body reactions, therefore it was assumed that they might interact with each other. The aim was to identify important genes that are expressed by osteoclasts and FBGCs which can be used to understand peri‐implantitis and predict the relationship of these cells during foreign body reactions. Bone marrow macrophages (BMM) were treated with receptor activator of nuclear factor kappa B ligand (RANKL) to produce osteoclasts. Quantitative PCR (qPCR) was used to identify the genes that were expressed by osteoclasts and FBGCs compared to macrophage controls. TRAP staining was used to visualise the cells while gelatine zymography and western blots were used for protein expression. Tartrate‐resistant acid phosphatase (TRAP), matrix metallo proteinase 9 (MMP9), nuclear factor of activated T cells 1 (NFATc1), cathepsin K (CTSK) and RANK were significantly lower in FBGCs compared to osteoclasts. Inflammation specific chemokines such as monocyte chemotactic protein (MCP1 also called CCL2), macrophage inflammatory protein 1 alpha (MIP1α), MIP1β and MIP1γ, and their receptors CCR1, CCR3 and CCR5, were highly expressed by FBGCs. FBGCs were negative for osteoclast specific markers (RANK, NFATc1, CTSK). FBGCs expressed chemokines such as CCL2, 3, 5 and 9 while osteoclasts expressed the receptors for these chemokines i.e. CCR1, 2 and 3. Our findings show that osteoclast specific genes are not expressed by FBGCs and that FBGCs interact with osteoclasts during foreign body reaction through chemokines. J. Cell. Biochem. 115: 1290–1298, 2014.

CCL2 and CCR2 are Essential for the Formation of Osteoclasts and Foreign Body Giant Cells.

Osteoclasts are multinucleated cells responsible for bone resorption. They are derived from the fusion of cells in the monocyte/macrophage lineage. Monocytes and macrophages can also fuse to form foreign body giant cells (FBGC). Foreign body giant cells are observed at the interface between a host and a foreign body such as implants during a foreign body reaction. Macrophages are attracted to the site of bone resorption and foreign body reactions by different cytokines. Chemokine (C‐C) ligand‐2 (CCL2) is an important chemotactic factor and binds to a receptor CCR2. In this study we investigated the importance of CCL2 and the receptor CCR2 in the formation of osteoclasts and FBGC. CCL2 mRNA was more highly expressed in giant cell culture than macrophages, being 9‐fold and 16‐fold more abundant in osteoclasts and FBGC respectively. Significantly fewer osteoclasts and FBGC were cultured from the bone marrow of CCL2 and CCR2 knockout mice, when compared to wild type. Not only were the number of giant cells reduced but there was a significant reduction in the number of nuclei and the size of these cells in the cultures of CCL2 and CCR2 knockout mice. Formation of osteoclasts and FBGC were recovered in cultures by addition of exogenous CCL2 to the media containing marrow cells from CCL2‐/‐ mice. We conclude that CCL2 and its receptor CCR2 are important for the formation of osteoclasts and FBGC and absence of these genes causes inhibition of osteoclast and FBGC formation. J. Cell. Biochem. 117: 382–389, 2016.

The need for virtual reality simulators in dental education: A review

Virtual reality simulators are becoming an essential part of modern education. The benefits of Virtual reality in dentistry is constantly being assessed as a method or an adjunct to improve fine motor skills, hand-eye coordination in pre-clinical settings and overcome the monetary and intellectual challenges involved with such training. This article, while providing an overview of the virtual reality dental simulators, also looks at the link between virtual reality simulation and current pedagogical knowledge.

Digital Cadavers: Online 2D Learning Resources Enhance Student Learning in Practical Head and Neck Anatomy within Dental Programs

Head and neck anatomy provides core concepts within preclinical dental curricula. Increased student numbers, reduced curricula time, and restricted access to laboratory-based human resources have increased technology enhanced learning approaches to support student learning. Potential advantages include cost-effectiveness, off-campus access, and self-directed review or mastery opportunities for students. This study investigated successful student learning within a first-year head and neck anatomy course at the School of Dentistry and Oral Health, Griffith University, Australia, taught by the same teaching team, between 2010 and 2015. Student learning success was compared, for cohorts before and after implementation of a supplementary, purpose-designed online digital library and quiz bank. Success of these online resources was confirmed using overall students’ performance within the course assessment tasks and Student Evaluation of Course surveys and online access data. Engagement with these supplementary 2D online resources, targeted at improving laboratory study, was positively evaluated by students (mean 85%) and significantly increased their laboratory grades (mean difference 6%, ), despite being assessed using cadaveric resources. Written assessments in final exams were not significantly improved. Expanded use of supplementary online resources is planned to support student learning and success in head and neck anatomy, given the success of this intervention.

Flipping a Dental Anatomy Course: A Retrospective Study Over Four Years

Flipped classrooms have been successfully used to increase student engagement and support student learning in a range of educational fields, including health education. These advantages for student learning supported implementation of the flipped classroom in introductory sciences and preclinical courses in dental education. We report on a 4-year retrospective study which compared two methods of delivery of a first-year dental anatomy course. The first method used the traditional method, consisting of face to face contact teaching hours, which was compared to a partial flipped classroom, where lecture contact was maintained but practical classes were flipped. A series of online videos demonstrating different practical tasks such as wax carving and tooth identification. An online digital library and online quizzes for self-reflected learning were developed and trialled. Students’ Evaluations of Course (SEC) and students’ overall performance in practical and theoretical assessments were used to evaluate the impact on student engagement and success, respectively, after implementation of the modified course offerings. This study evidences the success of the transition to a partially flipped course design. Careful design and consideration of implementation of the flipped classroom method in dental education are recommended to ensure that there is reliable availability of online resources and dedicated teaching staff for construction of resources and delivery of relevant in-class activities.

Can Virtual Simulators Replace Traditional Preclinical Teaching Methods: A Students’ Perspective?

Background Haptic simulators are starting to attract a lot of dental schools to use and implement as part of their preclinical training. However, there is not much data available about the possible ways it could be used to gain the maximum benefits. Students being the end users of this new technology should have a valuable opinion about this topic. Methods Twenty four dental students enrolled in the 4th and 5th years of the dental science program at the school of dentistry and oral health – Griffith University – Queensland – Australia participated in this study. Participants were offered a trial session on the Simodont® Dental Trainer and were asked to evaluate different aspects of this virtual simulator by completing a pre-experimental and post-experimental questionnaire. Results and conclusion All students valued and appreciated the additional educational benefits the Simodont® Dental Trainer can offer. Before the trial session, fourth year students were more excited and enthusiastic about using the haptic simulator. After the trial session, fifth year students rated the simulator in some aspects higher when compared to fourth year students. All students agreed that Simodont® Dental Trainer should be used in conjunction with other traditional educational methods and to be supplemented by feedback from human educators. Further trials are required to investigate the value of using haptic simulators over a whole semester or a year.

Anatomical sciences: A foundation for a solid learning experience in dental technology and dental prosthetics.

Basic science courses are extremely important as a foundation for scaffolding knowledge and then applying it in future courses, clinical situations as well as in a professional career. Anatomical sciences, which include tooth morphology, oral histology, oral embryology, and head and neck anatomy form a core part of the preclinical courses in dental technology programs. In this article, the importance and relevance of anatomical sciences to dental personnel with no direct contact with patients (dental technicians) and limited discipline related contact with patients (dental prosthetists) is highlighted. Some light is shed on the role of anatomical sciences in the pedagogical framework and its significance in the educational process and interprofessional learning of dental technicians and prosthetists using oral biology as an example in the dental curriculum. To conclude, anatomical sciences allow dental technicians and prosthetists to a gain a better insight of how tissues function, leading to a better understanding of diagnosis, comprehensive treatment planning and referrals if needed. Patient communication and satisfaction also increases as a result of this deep understanding of oral tissues. Anatomical sciences bridge the gap between basic science, preclinical, and clinical courses, which leads to a holistic approach in patient management. Finally, treatment outcomes are positively affected due to the appreciation of the macro and micro structure of oral tissues. Anat Sci Educ 10: 395–404.

A New Multi-Ingredient Recipe for the Treatment of Localized Advanced Periodontal Disease following the Surgical Removal of Impacted Wisdom Teeth

Periodontal disease is a chronic inflammation of the tooth supporting structures. It leads to bone and attachment loss which is irreversible. Extraction of horizontally impacted lower third molar (L3M) teeth may result in localized periodontal pockets at the distal aspect of the adjacent lower second molars (L2M). We present a case of a 21-year-old male who suffered from a swelling and pain around his lower right second molar following surgical removal of a mesioangular impacted lower right third molar. We showed that oral hygiene measures, surgical access, mixture of autogenous and synthetic bone graft, and guided tissue regeneration (GTR) were enough to control the problem.

Expression of cyclin D1 correlates with p27KIP1 and regulates the degree of oral dysplasia and squamous cell carcinoma differentiation

OBJECTIVES The aim of this study was to identify an association or link between cyclin D1 and p27KIP1 protein expression and dysplastic changes or progression. STUDY DESIGN Oral mucosal biopsies with a diagnosis of non-neoplastic tissue (gingivitis) (n = 10), mild to moderate oral epithelial dysplasia (n = 12), and oral squamous cell carcinoma (n = 11) were evaluated by using immunohistochemistry. Scanning software was used to determine cyclin D1 and p27KIP1 intensity of expression, location, and pattern. RESULTS A significant increase in expression of cyclin D1 and a decrease in expression of p27KIP1 proteins were identified in oral epithelial dysplasia and less differentiated oral squamous cell carcinoma (OSCC). There was a more diffuse distribution of cyclin D1 protein expression extending from the basal cell layer into the prickle cell layers in epithelial dysplasia and extending within all epithelial layers in OSCC. Cases of oral epithelial dysplasia had moderate infrequent expression of p27KIP1. There were no p27KIP1-positive cells in OSCC. The percentage of cells with both nuclear and cytoplasmic cyclin D1 staining was higher in OSCC specimens than control groups and oral epithelial dysplasia. CONCLUSIONS The expression of both cyclin D1 and p27KIP1 correlated with the grade of oral epithelial dysplasia and degree of OSCC differentiation. The results obtained will be verified through a basic follow-up of the cases to determine the prognosis/progression of oral dysplasia.