Current concepts in periodontal bioengineering

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73112/1/j.1601-6343.2005.00352.x.pd

Protein kinase A enhances lipopolysaccharide-induced IL-6, IL-8, and PGE2 production by human gingival fibroblasts

<p>Abstract</p> <p>Objective</p> <p>Periodontal disease is accompanied by inflammation of the gingiva and destruction of periodontal tissues, leading to alveolar bone loss in severe clinical cases. Interleukin (IL)-6, IL-8, and the chemical mediator prostaglandin E₂(PGE₂) are known to play important roles in inflammatory responses and tissue degradation.</p> <p>Recently, we reported that the protein kinase A (PKA) inhibitor H-89 suppresses lipopolysaccharide (LPS)-induced IL-8 production by human gingival fibroblasts (HGFs). In the present study, the relevance of the PKA activity and two PKA-activating drugs, aminophylline and adrenaline, to LPS-induced inflammatory cytokines (IL-6 and IL-8) and PGE₂by HGFs were examined.</p> <p>Methods</p> <p>HGFs were treated with LPS from <it>Porphyromonas gingivalis </it>and H-89, the cAMP analog dibutyryl cyclic AMP (dbcAMP), aminophylline, or adrenaline. After 24 h, IL-6, IL-8, and PGE₂levels were evaluated by ELISA.</p> <p>Results</p> <p>H-89 did not affect LPS-induced IL-6 production, but suppressed IL-8 and PGE₂production. In contrast, dbcAMP significantly increased LPS-induced IL-6, IL-8, and PGE₂production. Up to 10 μg/ml of aminophylline did not affect LPS-induced IL-6, IL-8, or PGE₂production, but they were significantly increased at 100 μg/ml. Similarly, 0.01 μg/ml of adrenaline did not affect LPS-induced IL-6, IL-8, or PGE₂production, but they were significantly increased at concentrations of 0.1 and 1 μg/ml. In the absence of LPS, H-89, dbcAMP, aminophylline, and adrenaline had no relevance to IL-6, IL-8, or PGE₂production.</p> <p>Conclusion</p> <p>These results suggest that the PKA pathway, and also PKA-activating drugs, enhance LPS-induced IL-6, IL-8, and PGE₂production by HGFs. However, aminophylline may not have an effect on the production of these molecules at concentrations used in clinical settings (8 to 20 μg/ml in serum). These results suggest that aminophylline does not affect inflammatory responses in periodontal disease.</p

Problem-based learning in dental education: what's the evidence for and against... and is it worth the effort?

The document attached has been archived with permission from the Australian Dental Association. An external link to the publisher’s copy is included.All Australian dental schools have introduced problem-based learning (PBL) approaches to their programmes over the past decade, although the nature of the innovations has varied from school to school. Before one can ask whether PBL is better than the conventional style of education, one needs to consider three key issues. Firstly, we need to agree on what is meant by the term PBL; secondly, we need to decide what “better” means when comparing educational approaches; and thirdly, we must look carefully at how PBL is implemented in given situations. It is argued that PBL fulfils, at least in theory, some important principles relating to the development of new knowledge. It also represents a change in focus from teachers and teaching in conventional programmes to learners and learning. Generally, students enjoy PBL programmes more than conventional programmes and feel they are more nurturing. There is also some evidence of an improvement in clinical and diagnostic reasoning ability associated with PBL curricula. The main negative points raised about PBL are the costs involved and mixed reports of insufficient grounding of students in the basic sciences. Financial restraints will probably preclude the introduction of pure or fully integrated PBL programmes in Australian dental schools. However, our research and experience, as well as other published literature, indicate that well-planned hybrid PBL programmes, with matching methods of assessment, can foster development of the types of knowledge, skills and attributes that oral health professionals will need in the future.T Winning and G Townsen

Rheumatoid arthritis and the role of oral bacteria

Rheumatoid arthritis (RA) and periodontal disease (PD) have shown similar physiopathologic mechanisms such as chronic inflammation with adjacent bone resorption in an immunogenetically susceptible host; however, PD has a well-recognized bacterial etiology while the cause of RA is unclear. Some reports have indicated that an infectious agent in a susceptible host could be one possible trigger factor for RA, and it has been suggested that oral microorganisms, specialty periodontal bacteria could be the infectious agent (mainly Porphyromonas gingivalis). It has been reported that PD is more frequent and more severe in patients with RA, suggesting a positive association between both diseases. There have been reports regarding the detection of antibodies against periodontal bacteria while other studies have identified periodontal bacterial DNA in serum and synovial fluid of RA patients and have explored the possible pathways of transport of periodontal bacterial DNA. In conclusion, there is no question that RA and PD have pathologic features in common and there is strong evidence of an association between both diseases, but further studies, including experimental models, are needed to demonstrate the arthritogenicity of oral microorganisms

Oral bisphosphonate-related osteonecrosis of the jaws in rheumatoid arthritis patients: a critical discussion and two case reports

<p>Abstract</p> <p>Background</p> <p>Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is a clinical condition characterized by the presence of exposed bone in the maxillofacial region. Its pathogenesis is still undetermined, but may be associated with risk factors such as rheumatoid arthritis (RA). The aim of this paper is to report two unpublished cases of BRONJ in patients with RA and to conduct a literature review of similar clinical cases with a view to describe the main issues concerning these patients, including demographic characteristics and therapeutic approaches applied.</p> <p>Methods</p> <p>Two case reports of BRONJ involving RA patients were discussed</p> <p>Results</p> <p>Both patients were aging female taking alendronate for more than 3 years. Lesions were detected in stage II in posterior mandible with no clear trigger agent. The treatment applied consisted of antibiotics, oral rinses with chlorhexidine, drug discontinuation and surgical procedures. Complete healing of the lesions was achieved.</p> <p>Conclusions</p> <p>This paper brings to light the necessity for rheumatologists to be aware of the potential risk to their patients of developing BRONJ and to work together with dentists for the prevention and early detection of the lesions. Although some features seem to link RA with oral BRONJ and act as synergistic effects, more studies should be developed to support the scientific bases for this hypothesis.</p

Effects of Aging and Cyclosporin A on Collagen Turnover in Human Gingiva

BACKGROUND: WE AIMED AT CHARACTERIZING THE AGING GINGIVA ANALYZING: i) collagen content and turnover in human gingival tissues and fibroblasts obtained from healthy young and aging subjects. ii) the effect of cyclosporin A administration in human cultured gingival fibroblasts obtained from aging compared to young subjects. METHODS: Morphological analysis was performed on haematoxylin-eosin and Sirius red stained paraffin-embedded gingival biopsies from young and aging healthy subjects. The expression of the main genes and proteins involved in collagen turnover were determined by real time PCR, dot blot and SDS-zymography on cultured young and aging gingival fibroblasts, and after cyclosporin A administration. RESULTS: Our results suggest that in healthy aged people, gingival connective tissue is characterized by a similar collagen content and turnover. Collagen turnover pathways are similarly affected by cyclosporin A treatment in young and aging gingival fibroblasts. CONCLUSIONS: Cyclosporin A administration affects gingival collagen turnover pathways in young and aging fibroblasts at the same extent, suggesting that during aging cyclosporin A administration is not related to relevant collagen turnover modifications