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More than 30 years have passed since the first successful application of regenerative therapy for treatment of periodontal diseases. Despite being feasible, periodontal regeneration still faces numerous challenges, and complete restoration of structure and function of the diseased periodontium is often considered an unpredictable task. This review highlights developing basic science and technologies for potential application to achieve reconstruction of the periodontium. A comprehensive search of the electronic bibliographic database PubMed was conducted to identify different emerging therapeutic approaches reported to influence either biologic pathways and/or tissues involved in periodontal regeneration. Each citation was assessed based on its abstract, and the full text of potentially eligible reports was retrieved. Based on the review of the full papers, their suitability for inclusion in this report was determined. In principle, only reports from scientifically well-designed studies that presented preclinical in vivo (animal studies) or clinical (human studies) evidence for successful periodontal regeneration were included. Hence, in vitro studies, namely those conducted in laboratories without any live animals, were excluded. In case of especially recent and relevant reviews with a narrow focus on specific regenerative approaches, they were identified as such, and thereby the option of referring to them to summarize the status of a specific approach, in addition to or instead of listing each separately, was preserved. Admittedly, the presence of subjectivity in the selection of studies to include in this overview cannot be excluded. However, it is believed that the contemporary approaches described in this review collectively represent the current efforts that have reported preclinical or clinical methods to successfully enhance regeneration of the periodontium. Today's challenges facing periodontal regenerative therapy continue to stimulate important research and clinical development, which, in turn, shapes the current concept of periodontal tissue engineering. Emerging technologies--such as stem cell therapy, bone anabolic agents, genetic approaches, and nanomaterials--also offer unique opportunities to enhance the predictability of current regenerative surgical approaches and inspire development of novel treatment strategies. [ABSTRACT FROM AUTHOR]

Background: Periostin is a matricellular protein essential for tissue integrity and maturation and is believed to have a key function asa modulator of periodontal ligament (PDL) homeostasis. The aim of this study is to evaluate whether periodontal disease-associated pathogen-related virulence factors (endotoxins/lipopolysaccharides [LPS]) and proinflammatory cytokines alter the expression of periostin in PDL cells. Methods: Human PDL cultures were exposed to inflammatory mediators (tumor necrosis factor-α [TNF-α]), bacterial virulence factors (Porphyromonas gingivalis LPS) ora combination in a biomechanically challenged environment. Culture conditions were applied for 24 hours, 4 days, and 7 days. Periostin and TGF-β inducible gene clone H3 (β1GH3) mRNA expression from cell lysates were analyzed. Periostin and βIGH3 proteins were also detected and semiquantified in both cell lysates and cell culture supernatants by Western blot. In addition, periostin localization by immunofluorescence was performed. Analysis of variance and Fisher tests were used to define the statistical differences among groups (P<0.05). Results: In a mechanically challenged environment, periostin protein was more efficiently incorporated into the matrix compared to the non-loaded controls (higher levels of periostin in the supernatant in the non-loaded group). Interestingly, chronic exposure to proinflammatory cytokines and/or microbial virulence factors significantly decreased periostin protein levels in the loaded cultures. There was greater variability on β1GH3 levels, and no particular pattern was clearly evident. Conclusions: lnflammatory mediators (TNF-α and bacterial virulence factors (P. gingivalis LPS) decrease periostin expression in human PDL fibroblasts. These results support a potential mechanism by which periostin alterations could actas a contributing factor during periodontal disease progression. [ABSTRACT FROM AUTHOR]

The article discusses research on the mechanical properties of bone. It references the study "Peri-Implant Bone Organization Under Immediate Loading Conditions: Collagen Fiber Orientation and Mineral Density Analyses in the Minipig Model," by T. Traini et al, published in "Clinical Implant Dentistry and Related Research" on July 23, 2008. In this study, the quality of osseointegration was evaluated by characterizing the degree of mineralization and the collagen fiber organization of the bone matrix in loaded and unloaded dental implants.