Psychological stress: neuroimmune roles in periodontal disease.

Periodontitis is a chronic inflammatory disease that starts with pathogenic bacteria and is mediated by a combination of multiple factors. Psychosomatic factors are considered to be one of the most critical risk factors for periodontal disease. Psychological stress may threaten periodontal immune homeostasis in multiple ways by affecting the hypothalamic-pituitary-adrenal cortex system, the locus ceruleus-sympathetic-adrenal medulla system, and the peptidergic nervous system. In this review, we outline the complex role of psychological stress in promoting the development of periodontal disease, focusing on the effects of stress on flora metabolism, tissue inflammation, and alveolar bone homeostasis. At the same time, we broadly and deeply summarize the potential mechanisms of psychological stress-induced periodontal disease, emphasize the importance of neuroimmune modulation for periodontal health, and expect to provide a new perspective for periodontal science based on psychoneuroimmunology.

Preparative Purification of Bioactive Compounds from Flos Chrysanthemi Indici and Evaluation of Its Antiosteoporosis Effect.

To understand the material basis and underlying molecular machinery of antiosteoporosis activity of the Flos Chrysanthemi Indici (FCI), the consequences of ethanol extract on the bone loss in mice induced due to ovariectomy (OVX) was evaluated. Also, the antiosteoporosis fraction obtained from the FCI ethanol extract was isolated and purified using a preparative high-speed countercurrent chromatography (HSCCC). The in vitro impact of the compounds was investigated on osteoblast proliferation and differentiation. The results revealed that ethyl acetate fraction with robust in vivo antiosteoporosis activity was obtained. The important compounds purified by HSCCC using gradient elution system included acacetin, apigenin, luteolin, and linarin. The four compounds enhanced the differentiation and proliferation of osteoblasts in MC3T3-E1 cells. They also augmented the mRNA levels of runt-related transcription factor 2 (Runx2), osteocalcin (OCN), osteopontin (OPN), and type I collagen (COL I). The AKT signaling pathway was also activated in MC3T3-E1 cells by the four compounds. The present study demonstrated that the antiosteoporosis effects of FCI did not depend on a single component, and HSCCC efficiently isolated and purified the antiosteoporosis bioactive compounds from FCI.

[The influence of thickness ratios on the fatigue behaviors of two kinds of dental ceramic].

OBJECTIVE: To investigate the intensity changes of different thickness ratios of Empress II glass ceramic and GI- II glass-infiltrated alumina ceramic before and after Hertzian contact cyclic fatigue. METHODS: Disk-shaped specimens of different thickness ratios of Empress II glass ceramic and GI-II glass-infiltrated alumina ceramic were respectively fabricated. Hertzian contact technique was imposed on the specimens. Critical loads of the specimens before and after 10(5) cycles loading were recorded. RESULTS: The average values of critical loads of all specimens reduced significantly after cycles loading (P < 0.05), and critical loads declined with diminishing thickness of the core ceramic. The critical load of GI-II glass-infiltrated alumina ceramic was significantly higher than Empress II glass ceramic before and after cycle loading(P < 0.05). CONCLUSION: Cycle loading can reduce the strengths of the two kinds of dental ceramic, and the latter is better than the former in the resistance to fracture and cyclic fatigue. Critical loads of the two kinds of dental ceramic are mainly influenced by the core ceramic's strength and thickness.

[Compared study of cyclic fatigue behaviors in two kinds of dental ceramic layers structures].

OBJECTIVE: To compare the difference in strength degradation and morphology damage of two dental ceramic materials after Hertzian contact cyclic fatigue. METHODS: Hertzian contact technique was used to investigate the response of Empress II glass ceramic and GI- II glass-infiltrated alumina ceramic to cyclic fatigue. Critical loads of specimens after different fatigue cycles were recorded. RESULTS: For Empress II glass ceramic, critical load had significantly difference between specimens after 10(5) cycles loading. No significant difference of critical load was found in GI- II glass-infiltrated alumina ceramic after cycles loading. CONCLUSION: GI- II glass-infiltrated alumina ceramic has better capability in resistance to cyclic loading. It may attribute to microstructure of material. Empress II glass ceramic shows a brittle damage model.