[Experts consensus on diagnostic and therapeutic strategies for malocclusions at early developing stage].

Early orthodontic intervention remains a controversial notion in current dental care regime. Whilst early orthodontic treatment for children is the province for orthodontic specialists, a growing number of general practitioners, who may not possess sufficient specialty knowledge, are also involved, raising the concerns about the propriety and quality of their treatment modalities. However, orofacial development of children and adolescents is in a very complicated environment. Comprehensive theoretical knowledge and a great wealth of practical experience are required to ensure the final treatment effect. The possible complications should be kept under control and fully informed to patients and their parents. In order to unify and standardize early orthodontic treatment protocol and help to promote healthy and orderly development of early orthodontic treatment, this consensus summarized the practical experience of orthodontic experts from many famous colleges and affiliated hospitals for clinical reference.

[Application of Vectra 3D facial imaging technology in orthodontic teaching program].

PURPOSE: To evaluate the effectiveness of Vectra 3D facial imaging technology in enhancing orthodontic teaching and training efficiency. METHODS: Thirty-two dental students, enrolled in 2014 as five-year and eight-year curriculum in School of Somatology, Air Force Military Medical University were selected as the subjects of this research. As an important teaching facility for training the students to practice orthodontic clinical examinations, 2D and 3D facial imaging systems were selected in this study for the students to collect and analyze the data relating to the facial complexion and appearance. The students were at first instructed to use the traditional 2D facial imaging system for 20 minutes, and then Vectra 3D facial imaging system for another 20 minutes. The students were required to deliberate on the specifically designed questionnaires to input their own assessment on these two modalities. The outcomes were quantitatively analyzed using SPSS 24.0 software package. RESULTS: As to the items 2, 5, 6 and 7 in the questionnaire, which indicated the following queries respectively: whether the use of imaging systems could inspire students' learning interest, whether the results drawn from these two imaging facial systems were accurate and reliable, whether the subjective bias were trivial , and whether these two imaging systems were feasible for orthodontic treatment appraisals. The results showed that there were significant differences in these four items between the two groups（P<0.05). As to the Items 1, 3 and 4 , namely, whether the acquisition of the teaching materials was an easy access, whether these two facial analytical regimes were beneficial for the students to obtain the new knowledge, and whether this specific teaching facility was easy for the students to manage, there was no significant difference between the two groups (P>0.05). CONCLUSIONS: Served as a new teaching syllabus facilitation, Vectra three-dimensional facial imaging system demonstrates a more satisfactory impetus for the students to learn than the traditional two-dimensional imaging system. Pragmatically, the analytical data resulted from the former remains more accountable than that of the latter.

Involvement of astrocytes activation in orofacial hyperalgesia induced by experimental tooth movement.

OBJECTIVE: The study aimed to investigate the involvement of astrocytes in the medullary dorsal horn (MDH) in the orofacial hyperalgesia induced by experimental tooth movement (ETM) and related mechanism. MATERIALS AND METHODS: Experimental tooth movement was produced with nickel-titanium alloy closed-coil spring fixed between the left maxillary first molar and the left upper incisor. Fluorocitrate was administrated through medullary subarachnoid at 3 days after ETM. Pressure pain threshold (PPT) in masseter cutaneous area was measured. The expression of glial fibrillary acidic protein (GFAP) and c-Fos in MDH was measured using immunofluoroscence staining. The expression of interleukin-1ß (IL-1ß) and phosphorylated N-methyl-D-aspartic acid (NMDA) receptor subunit NR1 (p-NR1) was measured with Western blotting. RESULTS: Experimental tooth movement-induced orofacial hyperalgesia from 1 to 9 days as the PPT was significantly reduced (P < .05). Immunofluoroscence staining showed that the expression of c-Fos in MDH was dramatically upregulated at 1 day and 3 days after ETM, while GFAP expression with both immunofluoroscence staining and Western blotting was significantly enhanced at 3 days and 7 days after ETM. Western blotting analysis indicated that the expression of IL-1ß and p-NR1 in MDH was significantly enhanced at 3 days after ETM. Furthermore, we found that fluorocitrate administration at 3 days after ETM could markedly suppress the expression of c-Fos, GFAP, IL-1ß and p-NR1 and attenuate the reduction of PPT induced by ETM. CONCLUSION: Astrocyte activation in MDH is involved in the mechanical hyperalgesia, and the subsequent upregulated IL-1ß and overexpression of p-NR1 may participate in this process.

A four-year prospective study of self-assembling nano-modified dental implants in patients with type 2 diabetes mellitus.

BACKGROUND/PURPOSE: Dental implantation has become an efficient and important method of replacing lost teeth. However, the success rate of dental-implant treatment in diabetics is higher than patients without diabetes. The aim of this study was to prospectively evaluate long-term marginal bone loss (MBL) and the stability of a self-assembling nano-modified implant in patients with type 2 diabetes mellitus compared with a conventional implant. MATERIALS AND METHODS: Twenty-five patients with type 2 diabetes were recruited for this study. Through a random selection process, one site in each patient received a conventional implant and the other site received a nano-modified implant. The implant stability quotient was measured using resonance frequency analysis (RFA), and MBL was measured using panoramic radiography from uncovering to four-year follow-up. RESULTS: No significant difference in implant stability quotient was found between the two groups (P > 0.05), except for the time at implant insertion (P < 0.05). MBL in the nano-modified implant group exhibited a decreasing change compared with the conventional implant group, between the uncovering and the loading stage (P < 0.05), while there was no significant difference in other stages (P > 0.05). CONCLUSION: There was potentially increased implant stability and diminished MBL around the self-assembling nano-modified implant in the uncovering-loading stage of early osseointegration in patients with type 2 diabetes.

MiR-106a* inhibits oral squamous cell carcinoma progression by directly targeting MeCP2 and suppressing the Wnt/ß-Catenin signaling pathway.

MicroRNAs (miRNAs) play critical roles in the tumorigenesis and progression of oral squamous cell carcinoma (OSCC). MiR-106a* functions as a tumor suppressor miRNA in several cancers; however, its role in OSCC has not been elucidated. We investigated the role of miR-106a* in human OSCC and explored its relevant mechanisms. The expression of miR-106a* was significantly downregulated in OSCC tissues and cell lines. The overexpression of miR-106a* inhibited OSCC cell proliferation and the cell cycle G1-S transition, and induced apoptosis. In contrast, inhibition of miR-106a* promoted cell proliferation and G1-S transition and suppressed apoptosis. The expression of miR-106a* inversely correlated with methyl-CpG binding protein 2 (MeCP2) expression in OSCC tissues. Using a luciferase reporter assay, MeCP2 was determined to be a direct target of miR-106a*. Overexpression of miR-106a* decreased MeCP2 expression at both the mRNA and protein levels, while inhibition of miR-106a* increased MeCP2 expression. Importantly, overexpression of MeCP2 eliminated the effects of miR-106a* overexpression in OSCC cells and silencing of MeCP2 recapitulated the cellular and molecular effects observed with miR-106a* overexpression. MeCP2 may promote OSCC cell proliferation by activating the Wnt/ß-Catenin signaling pathway. Taken together, our study demonstrated that miR-106a* inhibited OSCC cell proliferation by suppression of the Wnt/ß-Catenin signaling pathway and induced apoptosis through regulation of Caspase 3/9 expression via targeting MeCP2. These findings suggest that miR-106a* acted as a tumor suppressor in the progression of OSCC and may be a potential new target for OSCC diagnosis and therapy.

Effects of occlusion on mandibular morphology and architecture in rats.

BACKGROUND: A rodent occlusal hypofunction model has been widely established in jawbone-related studies. However, the effects of occlusal stimuli, with total elimination of molar contacts, and its rehabilitation on mandibular remodeling remain unclear. MATERIALS AND METHODS: Forty-eight 5-wk-old Sprague-Dawley male rats were used. Twenty-four experimental rats underwent occlusal hypofunction by insertion of a bite-raising appliance. Twenty-four rats received no treatment (control group). Two weeks later, half the experimental rats (occlusal hypofunction group) were killed; the appliance was removed from the remaining experimental rats (recovery group) for two additional weeks before killing. Control animals were killed biweekly. Body weight and masseter muscle weight were measured, and the mandibles were subjected to micro-computed tomography to evaluate the mandibular morphology and cortical bone characteristics. The expressions of osteoblast- and osteoclast-related genes were evaluated with quantitative polymerase chain reaction. RESULTS: No significant body weight differences were observed between the experimental and control rats. However, lighter masseter muscle, shorter mandibular incisor crown, mandibular body and ramus, and higher mandibular alveolar process and first molar fossae were observed in the occlusal hypofunction group. Moreover, the cortical bone characteristics associated with the expression of osteoblast- and osteoclast-related genes were remarkably different in the central and posterior mandible in the occlusal hypofunction group. At the 2-wk recovery time point after occlusal stimuli, the altered parameters in the masseter and mandible returned to normal levels. CONCLUSIONS: Mandibular remodeling via bone turnover is region specific for altered occlusal stimuli. Normal occlusion is an important determinant of the mandibular morphology and architecture.

Effect of occlusal hypofunction and its recovery on the three-dimensional architecture of mandibular alveolar bone in growing rats.

BACKGROUD: Normal occlusion is very important for physiological structure of mandible. However, the details of influences of occlusal hypofunction and its recovery on the three-dimensional architecture of mandibular alveolar bone in growing rats are still lacking. MATERIALS AND METHODS: Forty-eight growing male Sprague-Dawley rats were randomly divided into normal (n = 24), hypofunctional (n = 12), and recovery (n = 12) groups. The hypofunction group was developed by inserting a bite-raising appliance between the maxillary and mandibular incisors of the rats. Two weeks after insertion, the appliance was removed to result in the recovery group; the experiment continued for two additional weeks. The experimental animals and control animals were killed weekly. In addition to measuring the body weight and masseter muscle weight of the rats, the histomorphology and microstructure of the mandibular alveolar bone were scanned using microcomputed tomography. RESULTS: A lighter masseter muscle and a higher and narrower alveolar process were observed in the hypofunction group compared with the control animals (P < 0.05). Mandibular remodeling also occurred in the hypofunctional group, as demonstrated by a smaller trabecular cross-sectional area, looser trabecular bone, decreased bone volume fraction, trabecular thickness, trabecular number, and increased bone surface density and trabecular separation, especially at week 2 (P < 0.05). After removing the anterior bite-opening appliance, the altered masseter muscle weight and architecture of the mandibular alveolar bone were gradually reversed and reached normal levels at the end of the experiment (P > 0.05). CONCLUSIONS: A loss of occlusal stimuli can lead into mandibular alveolar bone remodeling, and the recovery of occlusion can restore the altered mandibular architecture in growing rats.

Effects of BMP-2 and dexamethasone on osteogenic differentiation of rat dental follicle progenitor cells seeded on three-dimensional beta-TCP.

The aim of this study was to investigate the effects of BMP-2 and dexamethasone (Dex) on osteogenic differentiation of rat dental follicle progenitor cells (RDFCs) seeded on three-dimensional beta-TCP. The alkaline phosphatase (ALP), the calcium and phosphonium, the osteocalcin in media of the third passage RDFCs on biomaterial beta-TCP after 1-3, 3-7, 7-14 days of culture were examined respectively. The growth of cells on the scaffolds was observed by scanning electron microscope (SEM) after 3, 7 days of culture and by implanting in the backs of severe combined immunodeficient (SCID) mice for bone regeneration. The third passage RDFCs could be seen adhered, extended and proliferated on the beta-TCP by scanning electron microscopy. The ALP activity, the calcium and phosphoniums and the osteocalcin content of dexamethasone (10(-8) M) or/and BMP-2 (100 ng ml(-1)) were significantly higher than their existence in the control group. They were the significantly highest among four groups after joint application of BMP-2 and dexamethasone. After 8 weeks of implantation, the percentage of the new bones formed area in the RDFCs+beta-TCP+BMP-2+Dex group was significantly higher than that in the RDFCs+beta-TCP+BMP-2 group. In contrast, beta-TCP, RDFCs+beta-TCP+Dex and control constructs lacked new bone formation by histological staining and histomorphometric analysis. The BMP-2+Dex could significantly promote osteogenic differentiation of RDFCs on beta-TCP. beta-TCP supported fast cellular adhesion, proliferation and differentiation of RDFCs. The feasibility of its application in periodontal tissue engineering was also proved.

Osteogenic-related gene expression profiles of human dental follicle cells induced by dexamethasone.

AIM: Human dental follicle cells (hDFC) have the ability to differentiate into mineralized tissue-forming cells during root and periodontal development or osteogenic induction in vitro. The present study aimed to validate the osteogenic induction of hDFC by dexamethasone (DEX) and to explore the changes of related genes responsible for the osteogenic differentiation process. METHODS: Passage-cultured hDFC were induced by DEX and analyzed for mineralization activity by morphological observation, alkaline phosphatase (ALP) activity, and alizarin red S staining. GEArray Q series human osteogenesis gene array was used to describe large-scale gene expression in treated hDFC compared to the control group. Quantitative real-time RT-PCR was performed to confirm the microarray data by analyzing the expression of 7 critical transcripts. RESULTS: Osteogenic differentiation of hDFC was confirmed by morphological change, elevated ALP activity and calcified nodules. In 96 genes investigated through the microarray analysis, 20 genes were upregulated and 8 genes were downregulated more than 2-fold. The results of the real-time RT-PCR correlated with the microarray analysis. The expression of the transforming growth factor-beta superfamily showed varying degrees of increase, and fibroblast growth factors exhibited a differential changing trend of expression. The expression of most types of collagen genes representative of extracellular matrixes increased under DEX treatment while small mothers against decapentaplegic 6 and 7 expressions significantly decreased. CONCLUSION: Our results demonstrated that hDFC displayed osteoblastic features in both phenotypic and genotypic traits induced by DEX in vitro.

Expression of vascular endothelial growth factor in cultured human dental follicle cells and its biological roles.

AIM: To investigate the expression of vascular endothelial growth factor (VEGF) in cultured human dental follicle cells (HDFC), and to examine the roles of VEGF in the proliferation, differentiation, and apoptosis of HDFC in vitro. METHODS: Immunocytochemistry, ELISA, and RT-PCR were used to detect the expression and transcription of VEGF in cultured HDFC. The dose-dependent and the time-course effect of VEGF on cell proliferation and alkaline phosphatase (ALP) activity in cultured HDFC were determined by MTT assay and colorimetric ALP assay, respectively. The effect of specific mitogen-activated protein kinase (MAPK) inhibitors (PD98059 and U0126) on the VEGF-mediated HDFC proliferation was also determined by MTT assay. The effect of VEGF on HDFC apoptosis was measured by flow cytometry. RESULTS: VEGF was transcribed and expressed in cultured HDFC. VEGF at 10-300 microg/L significantly increased HDFC proliferation and ALP activity compared to the control. Following 1, 3, 5, or 7 d of stimulation, VEGF induced a significant increase in HDFC proliferation compared with the corresponding control, while VEGF was effective at increasing ALP activity at the incubation time point of 3, 5, or 7 d. PD98059 and U0126 could attenuate the VEGF-mediated HDFC proliferation. Fewer apoptotic cells were observed in the VEGF-treated groups compared to the controls, although the difference was not statistically significant. CONCLUSION: VEGF is expressed in cultured HDFC, and at a proper concentration range can stimulate HDFC proliferation, induce HDFC to differentiate in a "cementoblast/osteoblast" pathway and protect HDFC from apoptosis. The MAPK signaling pathway might be involved in the VEGF-mediated HDFC proliferation.

[Effects of programmed cell death on human dental follicle cells and changes of programmed cell death under different hydrostatic pressures].

OBJECTIVE: Tooth eruption requires the presence of the dental follicle (DF) around the unerupted tooth. This study is to investigate programmed cell death on human dental follicle cells and changes of programmed cell death under different hydrostatic pressures: 0, 50 and 100 kPa. METHODS: Human dental follicles from third mandibular molars were surgically removed from adolescents who need for orthodontics treatment after informed content, then trypsinized and cultured. Human dental follicle cells were divided into three groups according to different hydrostatic pressures: 0, 50 and 100 kPa and their programmed cell death were labeled by using TdT-medi-ated-dUTP nick and labeling (TUNEL). RESULTS: Dental follicle cells cultured were elongate shape and exhibited fibroblastic characteristics. Compared with 0 kPa, programmed cell death cells on human dental follicle cells were increased 0.23% and 31.65% under 50 kPa and 100 kPa hydrostatic pressures respectively. 100 kPa group increased significantly (P < 0.01). CONCLUSION: It suggested that programmed cell death occured in human dental follicle cells cultured in vitro and was influenced by different hydrostatic pressures. Hydrostatic pressure may improve tooth erup-tion through dental follicle.