Effects of Drynaria Total Flavonoid on the Microstructure of the Mandible in Ovariectomized Rats.

BACKGROUND The aim of this study is to investigate the effects of Drynaria total flavonoids (DTF) on mandible microarchitecture, serum estrogen (E2), osteoprotegerin (OPG), and receptor activator of nuclear factor kappa-B ligand (RANKL) levels in an ovariectomy-induced osteoporosis rat model. MATERIAL AND METHODS Thirty female Sprague-Dawley rats were divided into 5 groups (n=6 per group): sham surgery, ovariectomy (OVX), and low-dose, middle-dose, and high-dose DTF. Mandibular osteoporosis was induced by ovariectomy; an equal amount of ovary-sized fat tissue was removed from the sham group. The DTF-treated groups were given DTF gavage at different doses for 12 weeks; the sham and OVX groups were given saline. After the treatment phase, the effects of DTF on the microarchitecture of the mandible were evaluated by measuring bone density, maximum load, morphometric parameters, and histopathological alterations. Serum E2, OPG, and RANKL levels were measured. RESULTS The OVX group showed obvious osteoporosis in the mandible and decreased serum E2 levels and OPG/RANKL ratio. The low-dose group did not show significant improvement in mandibular microstructure. The middle-dose group showed significantly ameliorated osteoporosis. The high-dose group had further improvement in bone microstructures and increase of OPG/RANKL over the middle-dose group. Furthermore, ovariectomy significantly decreased serum E2, but DTF treatment failed to restore serum E2 levels. CONCLUSIONS Ovariectomy can cause significant bone loss in the rat mandible and a decrease in serum E2 and OPG/RANKL. DTF significantly improved the mandibular microstructure and restored OPG/RANKL balance, but it did not restore the decreased serum E2 concentration following ovariectomy.

Worldwide tendency and perspectives in traumatic dental injuries: A bibliometric analysis over two decades (1999-2018).

BACKGROUND/AIMS: Traumatic dental injuries (TDIs) are considered to be a public dental health problem worldwide. The aim of the current study was to provide the worldwide tendency and perspectives in TDIs in the last two decades via bibliometric analysis. METHODS: ''Tooth injuries'' was searched as the Medical Subject Headings term within PubMed with the date range from 1999 to 2018. Two investigators perused information in the articles according to the inclusion and exclusion criteria. The articles were independently categorized according to the following aspects: (a) annual scholarly output; (b) leading countries or regions; (c) leading journals; (d) productive authors; (e) citations; (f) study design; (f) distribution of topics; and (g) the type of dentition and TDIs. VOSviewer 1.6.7 and Citespace 5.2 were used for analyzing and visualizing bibliometric networks. RESULTS: A total of 2627 articles about traumatic dental injuries were published and indexed in PubMed during the two decades, and the number of publications on traumatic dental injuries was rising in general. The research outputs were mainly concentrated in developed countries and affiliated hospitals of universities. Brazil was the most productive country. The journal Dental Traumatology had the most contributions to the scientific research of traumatic dental injuries. "Case report" was the most frequent type of article (36.50%), followed by cross-sectional studies (19.57%) and case-control studies (13.67%). Most studies focused on the treatment of TDIs (38.94%), especially for avulsion (21.01%), crown fracture (9.71%), and intrusion (5.25%). Permanent teeth (66%) were the dominant dentition. CONCLUSION: There is a lack of high-quality well-designed studies such as cohort studies. The number of publications on prevention and the primary dentition is disproportionate in relation to their significance.

In vitro study on non-thermal argon plasma in improving the bonding efficacy between dentin and self-etch adhesive systems.

Self-etch adhesive systems have the advantages of simple operating steps and low technique sensitivity. However, some deficiencies of self-etch adhesive result that the immediate bonding strength between self-etch adhesive and dentine is not so high. Non-thermal atmospheric pressure plasma (NTAPP) can be used for surface modification. Previous studies of our research group have proven that NTAPP can improve bonding durability between dentine and etch-and-rinse adhesive. However, it is still unknown whether NTAPP can improve bonding strength between dentine and self-etch adhesive. The study observed the contact angle on dentine surface, the adhesive permeability and MTBS. The study proved that NTAPP can improve dentine surface wettability, clear up smear layer, and enhanced the self-etch adhesive permeability in dentine bonding interface. In conclusion, NTAPP could improve the bonding strength between dentine and self-etch adhesive systems. The most optimum treating time was 15 s.