Knowledge of Infection Prevention and Attitudes Towards HIV/AIDS Among Chinese Dental Bachelor Interns: An Appeal for Educational Intervention.

PURPOSE: The present study aimed to assess the current situation of Chinese dental bachelor interns on HIV/AIDS-related knowledge and their attitudes towards HIV/AIDS patients. MATERIALS AND METHODS: A cross-sectional, paper-based survey involving 147 dental students from three Chinese dental schools was conducted. Students were recruited to complete the questionnaire regarding their knowledge, awareness and attitudes concerning HIV/AIDS anonymously and voluntarily. RESULTS: A total of 144 students responded to the study, generating a response rate of 98.0%. Although 97.0% of the dental students believed dentists were at high risk of HIV infection, 97.2% of students expressed no prejudice towards HIV/AIDS patients and stated their willingness to provide oral healthcare service for such patients. No statistically significant differences in the responses on attitudes and some basic knowledge were found between students who had received the relevant education about infection control and the students who had not. However, regarding most questions about oral manifestations in adult and paediatric patients living with AIDS, the students who received relevant education showed more knowledge than the students who did not (p <0.05). The cognitive level about respecting HIV/AIDS patients' autonomy and privacy was generally low in all the students. CONCLUSIONS: Most of the dental students in this survey held positive attitudes towards HIV/AIDS patients and good grasp of some basic knowledge about HIV/AIDS. On the other hand, the questionnaire results reflected gaps in education, such as respecting HIV/AIDS patients' privacy.

Influence of epigallocatechin-3-gallate in promoting proliferation and osteogenic differentiation of human periodontal ligament cells.

BACKGROUND: Epigallocatechin-3-gallate (EGCG) was recently proposed to have the potential to regulate bone metabolism, however, its influence on osteogenesis remains controversial. The present study aimed to investigate the effects of EGCG on the proliferation and osteogenesis of human periodontal ligament cells (hPDLCs). METHODS: Cells were cultured in osteogenic medium and treated with EGCG at various concentrations. Cell proliferation was analyzed using a CCK-8 assay and acridine orange (AO)/ethidium bromide (EB) staining. Flow cytometry was used to measure the intracellular reactive oxygen species (ROS) potential of hPDLCs. The expression levels of osteogenic marker genes and proteins in hPDLCs, including type I collagen (COL1), runt-related transcription factor 2 (RUNX2), osteopontin (OPN), and osterix (OSX), were determined by quantitative real-time polymerase chain reaction (qRT-PCR) and western blot analysis. In addition, alkaline phosphatase (ALP) activity was monitored both quantitatively and qualitatively. Extracellular matrix mineralization was further analyzed by alizarin red S staining. RESULTS: The results showed that EGCG concentrations from 6 to 10 µM increased the ROS level and inhibited the cell proliferation of hPDLCs. EGCG concentrations from 2 to 8 µM effectively increased extracellular matrix mineralization, in which 4 and 6 µM EGCG generated the most mineralizing nodules. The ALP activity and the mRNA and protein expression levels of the tested osteogenic markers were most strongly up-regulated by treatment with 4 and 6 µM EGCG. CONCLUSIONS: The present study demonstrated that EGCG might promote the osteogenesis of hPDLCs in a dose-dependent manner, with concentrations of 4 and 6 µM EGCG showing the strongest osteogenic enhancement without cytotoxicity, indicating a promising role for EGCG in periodontal regeneration in patients with deficient alveolar bone in the future.

Contribution of Mitophagy to Cell-Mediated Mineralization: Revisiting a 50-Year-Old Conundrum.

Biomineralization in vertebrates is initiated via amorphous calcium phosphate (ACP) precursors. These precursors infiltrate the extracellular collagen matrix where they undergo phase transformation into intrafibrillar carbonated apatite. Although it is well established that ACP precursors are released from intracellular vesicles through exocytosis, an unsolved enigma in this cell-mediated mineralization process is how ACP precursors, initially produced in the mitochondria, are translocated to the intracellular vesicles. The present study proposes that mitophagy provides the mechanism for transfer of ACP precursors from the dysfunctioned mitochondria to autophagosomes, which, upon fusion with lysosomes, become autolysosomes where the mitochondrial ACP precursors coalesce to form larger intravesicular granules, prior to their release into the extracellular matrix. Apart from endowing the mitochondria with the function of ACP delivery through mitophagy, the present results indicate that mitophagy, triggered upon intramitochondrial ACP accumulation in osteogenic lineage-committed mesenchymal stem cells, participates in the biomineralization process through the BMP/Smad signaling pathway.

Energy Storage and Dissipation of Human Periodontal Ligament during Mastication Movement.

As a layer of soft fibrous tissue, the periodontal ligament (PDL) protects against mechanical shock when transmitting mastication force from tooth to its surrounding alveolar bone. Currently, no quantitative method is available to estimate the shock resistance ability of the PDL. To solve this problem, in the present study we developed a finite element (FE) model of the tooth-PDL-bone complex and analyzed the energy storage and dissipation during the mastication movements. Displacement and Mises stress of tooth-PDL-bone complex show that the PDL is able to protect the alveolar bone from mechanical shock by shielding the transfer of deformation and stress. During mastication, the energy of the PDL is stored up to ∼161.5 J/mm3 at the period of loading and dissipated about one-tenth of the stored energy when unloading. The energy storage is displacement-dependent but time-independent because of the hyperelasticity of PDL. However, the energy dissipation is time- and displacement-dependent because of the viscoelasticity of PDL. The present study helps to understand the periodontal potential and the origin of dental diseases such as tooth concussion and occlusal trauma from the view of energy conversion.

PTENp1, a natural sponge of miR-21, mediates PTEN expression to inhibit the proliferation of oral squamous cell carcinoma.

PTENp1, non-coding RNA (ncRNA) pseudogene, is involved in oral squamous cell carcinoma (OSCC). The precise effects mediated by PTENp1 transcripts within intricate regulatory networks involving molecular interactions with ancestral gene PTEN and tumorigenicity in OSCC remain unclear. Here, we found that PTENp1 was aberrantly expressed in OSCC. There was a positive correlation between the expression levels of PTENp1 and PTEN. Further, we showed that PTENp1 acted as a competing endogenous RNA that protects PTEN transcripts from being inhibited by miR-21, and consequently inhibited proliferation and colony formation and triggered S-G2/M cell cycle arrest through the AKT pathway. Also, the homogeneous relationship between expression of PTENp1 and PTEN was confirmed in OSCC tumor xenografts. Finally, low expression of PTENp1 and PTEN was negatively associated with histological differentiation and OSCC prognosis. The present work provided the first evidence for the extraordinary crosstalk among PTENp1, PTEN, and miR-21, and rendered a new light on the treatment of OSCC. © 2016 Wiley Periodicals, Inc.