Xianrui Yang

Ultrasonography for detection of disc displacement of temporomandibular joint: a systematic review and meta-analysis

PURPOSE To assess the diagnostic efficacy of ultrasonography in detecting disc displacement of the temporomandibular joint. MATERIALS AND METHODS MEDLINE (using OVID, 1950 to April 2011), EMBASE (1980 to April 2011), and the Chinese Biomedical Literature Database (1978 to April 2011) were searched electronically. In addition, relevant journals and reference lists of the included studies were manually searched for any eligible studies on diagnostic accuracy. Two authors performed the study inclusion, data extraction, and risk of bias assessment in duplicate. Meta-analysis was performed with MetaDisc 1.4. RESULTS Fifteen studies were included in this meta-analysis; 6 studies had a low risk of bias, 6 studies an unclear risk, and 3 studies a high risk. Meta-regression indicated that the detected results were not influenced by the types of ultrasonography, image dimensions, types of transducer, and ultrasonic image of the disc (P > .05). The Q* values of ultrasonography for the closed- and open-mouth positions were 0.79 and 0.91, respectively. The diagnostic efficacy of disc displacement with reduction had a sensitivity of 0.76, a specificity of 0.82, a positive likelihood ratio of 3.80, a negative likelihood ratio of 0.36, a diagnostic odds ratio of 10.95, an area under the curve of 0.83, and a Q* of 0.76. The diagnostic efficacy of disc displacement without reduction had a sensitivity of 0.79, a specificity of 0.91, a positive likelihood ratio of 80.5, a negative likelihood ratio of 0.25, diagnostic odds ratio of 36.80, an area under the curve of 0.97, and a Q* of 0.92. CONCLUSIONS The diagnostic efficacy of ultrasonography is acceptable and can be used as a rapid preliminary diagnostic method to exclude some clinical suspicions. However, positive ultrasonographic findings should be confirmed by magnetic resonance imaging. Also, the ability of ultrasonography to detect lateral and posterior displacements is still unclear. More high-quality studies are needed to assess the diagnostic efficacies of some specific ultrasonographic methods. Standards and criteria for ultrasonographic techniques in the diagnosis of disc displacement should be established in the future.

Graft for prevention of Frey syndrome after parotidectomy: a systematic review and meta-analysis of randomized controlled trials.

PURPOSE To detect the effect and safety of different types of grafts for the prevention of Frey syndrome after parotidectomy. MATERIALS AND METHODS The following data bases were searched electronically: MEDLINE (using OVID, from 1948 to July 2011), Cochrane Central Register of Controlled Trials (CENTRAL, issue 2, 2011), EMBASE (available from: http://embase.com, 1984 to July 2011), World Health Organization International Clinical Trials Registry Platform (July 2011), Chinese BioMedical Literature Database (1978 to July 2011), and the China National Knowledge Infrastructure (1994 to July 2011). The relevant journals and reference lists of the included studies were manually searched for randomized controlled trials studying the effect and safety of different types of grafts for preventing Frey syndrome after parotidectomy. The risk of bias assessment using Cochrane Collaborations tool and data extraction was independently performed by 2 reviewers. The meta-analysis was performed using Review Manager, version 5.1. RESULTS A total of 14 randomized clinical trials and 1,098 participants were included. All had an unclear risk of bias. The meta-analysis results showed that the use of an acellular dermis matrix can reduce by 82% the risk of Frey syndrome compared with the no-graft group using an objective assessment (relative risk [RR] 0.18, 95% confidence interval [CI] 0.12 to 0.26; P < .00001; Grading of Recommendations, Assessment, Development, and Evaluation [GRADE] quality of evidence: high). The acellular dermis matrix can also reduce by 90% the risk of Frey syndrome compared with the no-graft group using a subjective assessment (RR 0.10, 95% CI 0.05 to 0.22; P < .00001; GRADE quality of evidence: high). The muscle flaps can reduce by 81% the risk of Frey syndrome compared with the no-graft group (RR 0.19, 95% CI 0.13 to 0.27; P < .00001; GRADE quality of evidence: high). No statistically significant difference was found between the acellular dermal matrix and muscle flap groups (RR 0.73, 95% CI 0.15 to 3.53, P = .70; GRADE quality of evidence: low). No serious adverse events were reported. CONCLUSIONS The present clinical evidence suggests that grafts are effective in preventing Frey syndrome after parotidectomy. More randomized clinical trials are needed to confirm our conclusions and prove the safety of the grafts.

Sclerostin Promotes Bone Remodeling in the Process of Tooth Movement

Tooth movement is a biological process of bone remodeling induced by mechanical force. Sclerostin secreted by osteocytes is mechanosensory and important in bone remodeling. However, little is known regarding the role of sclerostin in tooth movement. In this study, models of experimental tooth movement were established in rats and mice. Sclerostin expression was investigated with immunohistochemistry staining, and osteoclastic activity was analyzed with tartrate-resistant acid phosphatase (TRAP) staining. MLO-Y4 osteocyte-like cells underwent uniaxial compression and tension stress or were cultured in hypoxia conditions. Expression of sclerostin was assessed by RT-qPCR and ELISA. MLO-Y4 cells were cultured with recombinant human sclerostin (rhSCL) interference and then co-cultured with RAW264.7 osteoclast precursor cells. Expressions of RANKL and OPG were analyzed by RT-qPCR, and osteoclastic activity was assessed by TRAP staining. During tooth movement, sclerostin was expressed differently in compression and tension sites. In SOST knock-out mice, there were significantly fewer TRAP-positive cells than in WT mice during tooth movement in compression sites. In-vitro studies showed that the expression of sclerostin in MLO-Y4 osteocyte-like cells was not different under a uniaxial compression and tension force, whereas hypoxia conditions significantly increased sclerostin expression in MLO-Y4 cells. rhSCL interference increased the expression of RANKL and the RANKL/OPG ratio in MLO-Y4 cells and the osteoclastic induction ability of MLO-Y4 cells in experimental osteocyte-osteoclast co-culture. These data suggest that sclerostin plays an important role in the bone remodeling of tooth movement.

Effects of self-ligating brackets on oral hygiene and discomfort: a systematic review and meta-analysis of randomized controlled clinical trials.

Background: Self‐ligating brackets (SLBs) are widely adopted in clinic owing to their claimed superiorities. Here, we collected and analysed all randomized controlled clinical trials (RCTs) comparing SLBs with conventional brackets (CBs) and thereby investigated whether SLBs can relieve discomfort or promote oral hygiene. Methods: Electronic databases including MEDLINE, Cochrane Central Register of Controlled Trials, EMBASE, World Health Organization International Clinical Trials Registry Platform, Chinese BioMedical Literature Database and the China National Knowledge Infrastructure were searched to find out RCTs comparing active or passive SLBs with CBs. Two reviewers extracted the data and assessed risks of bias independently. Any disagreement between them was resolved through discussion with a third reviewer. Meta‐analysis was conducted on Review Manager 5.3. Results: A total of 12 RCTs with 575 participants were included, and eight of the trials were synthesized quantitatively. Two trials were assessed as low risk of bias, whereas others as unclear risk of bias. Passive SLBs and CBs are not significantly different in plaque control. SLBs and CBs are not significantly different in discomfort reduction at any of four time points (4 h, 24 h, 3 days and 7 days). Conclusions: Clinical evidences from existing RCTs suggest that SLBs do not outperform CBs in reliving discomfort or promoting oral health in clinic.

Effect of sclerostin removal in vivo on experimental periodontitis in mice

We explored the effects of sclerostin removal in vivo on experimental periodontitis in mice. A ligature of Porphyromonas gingivalis-saturated collagen silk was applied to the cervical region of the first molar tooth in 10 wild-type (WT) mice and 10 sclerostin-knockout (SOST-KO) mice, and the animals were fed 10% sucrose for 2 months. Another 10 WT mice and 10 SOST-KO mice were similarly treated, but then fed a normal diet for 2 months. The maxillae were then harvested for morphological and molecular examinations. The mice with periodontitis showed significantly more severe alveolar bone loss than control mice, the most significant absorption being observed in WT mice. Immunohistochemical staining demonstrated upregulation of RANKL and ERK1/2-MAPK expression and downregulation of OPG expression in mice with periodontitis, especially WT mice. Therefore, removal of sclerostin appears to modestly protect the alveolar bone from resorption in this experimental setting. (J Oral Sci 58, 271-276, 2016).

Inhibition of Ape1 Redox Activity Promotes Odonto/osteogenic Differentiation of Dental Papilla Cells.

Dentinogenesis is the formation of dentin, a substance that forms the majority of teeth, and this process is performed by odontoblasts. Dental papilla cells (DPCs), as the progenitor cells of odontoblasts, undergo the odontogenic differentiation regulated by multiple cytokines and paracrine signal molecules. Ape1 is a perfect paradigm of the function complexity of a biological macromolecule with two major functional regions for DNA repair and redox regulation, respectively. To date, it remains unclear whether Ape1 can regulate the dentinogenesis in DPCs. In the present study, we firstly examed the spatio-temporal expression of Ape1 during tooth germ developmental process, and found the Ape1 expression was initially high and then gradually reduced along with the tooth development. Secondly, the osteo/odontogenic differentiation capacity of DPCs was up-regulated when treated with either Ape1-shRNA or E3330 (a specific inhibitor of the Ape1 redox function), respectively. Moreover, we found that the canonical Wnt signaling pathway was activated in this process, and E3330 reinforced-osteo/odontogenic differentiation capacity was suppressed by Dickkopf1 (DKK1), a potent antagonist of canonical Wnt signaling pathway. Taken together, we for the first time showed that inhibition of Ape1 redox regulation could promote the osteo/odontogenic differentiation capacity of DPCs via canonical Wnt signaling pathway.

Effects of TGF-β1 on OPG/RANKL Expression of Cementoblasts and Osteoblasts Are Similar without Stress but Different with Mechanical Compressive Stress

Introduction. This study aimed to explore the effects of TGF-β1 on regulating activities of cementoblasts and osteoblasts with or without stress. Material and Methods. Human recombinant TGF-β1 was added with different doses. Immunohistochemical test of osteoprotegerin (OPG)/receptor activator of nuclear factor-kappaB ligand (RANKL) and Alizarin Red-S staining were conducted. Mechanical compressive stress was obtained by increasing the pressure of gaseous phase. OPG/RANKL expression was detected in both cells through quantitative real-time PCR. Results. Similar significant differences (P < 0.05) existed in OPG/RANKL change with increasing concentration of TGF-β1 without mechanical stress for cementoblasts and osteoblasts. However, under 3 h stress, OPG increased and RANKL decreased significantly (P < 0.01) but with similar OPG/RANKL change. Moreover, under 24 h stress, OPG change exhibited no difference (P > 0.05), but RANKL decreased significantly (P < 0.01) at 10 and 100 ng/mL TGF-β1 in cementoblasts. In osteoblasts, OPG increased significantly (P < 0.01) at 10 and 100 ng/mL, whereas RANKL decreased with statistical difference (P < 0.05) at 1 and 10 ng/mL. Conclusions. The effects of TGF-β1 on OPG/RANKL expression of cementoblasts and osteoblasts are similar even without mechanical stress. However, these effects are different under mechanical compressive stress.

Role of sagittal and oblique smiling profiles in evaluating facial esthetics.

IntroductionSurgeons and orthodontists used to use a conventional set of facial photographs, composed of front, front smiling, and profile images to evaluate facial esthetics, whereas sagittal and oblique smiling profile images have been largely neglected in practice. The aim of this study was to explore the importance of sagittal and oblique smiling profiles in evaluating facial esthetics. MethodsPhotographs from 80 patients, of whom 40 underwent orthognathic surgery and 40 underwent orthodontic treatment, including front, front smiling, profile, sagittal profile smiling, and oblique profile smiling images before and after treatment, were collected and synthesized into 6 categories. Thirty judges gave scores to these photographs based on their own esthetic conception with a 1-week interval for each category. ResultsThe results demonstrated that the mean score change of evaluating facial attractiveness of patients who underwent orthognathic surgery was lower when adding sagittal or oblique smiling profiles before the treatment, whereas it was higher after the treatment, which were opposite to the orthodontic treatment group with a higher score before the treatment and a lower score after the treatment when sagittal or oblique smiling profiles were added. The changes have a significant difference in adding both sagittal smiling profiles (P < 0.05) and oblique smiling profiles (P < 0.05) before and after treatment. ConclusionsAlong with oblique smiling profile, sagittal smiling profile is crucial in evaluating facial esthetics for orthodontic treatment and orthognathic surgery. Both of them suggested to be integrated in routine photographic assessment of facial attractiveness evaluation before and after treatment, especially in orthognathic surgery for facial esthetic evaluation.

Transversal changes, space closure, and efficiency of conventional and self-ligating appliances

ObjectiveSelf-ligating brackets (SLBs) were compared to conventional brackets (CBs) regarding their effectiveness on transversal changes and space closure, as well as the efficiency of alignment and treatment time.MethodsAll previously published randomized controlled clinical trials (RCTs) dealing with SLBs and CBs were searched via electronic databases, e.g., MEDLINE, Cochrane Central Register of Controlled Trials, EMBASE, World Health Organization International Clinical Trials Registry Platform, Chinese Biomedical Literature Database, and China National Knowledge Infrastructure. In addition, relevant journals were searched manually. Data extraction was performed independently by two reviewers and assessment of the risk of bias was executed using Cochrane Collaboration’s tool. Discrepancies were resolved by discussion with a third reviewer. Meta-analyses were conducted using Review Manager (version 5.3).ResultsA total of 976 patients in 17 RCTs were included in the study, of which 11 could be produced quantitatively and 2 showed a low risk of bias. Meta-analyses were found to favor CB for mandibular intercanine width expansion, while passive SLBs were more effective in posterior expansion. Moreover, CBs had an apparent advantage during short treatment periods. However, SLBs and CBs did not differ in closing spaces.ConclusionsBased on current clinical evidence obtained from RCTs, SLBs do not show clinical superiority compared to CBs in expanding transversal dimensions, space closure, or orthodontic efficiency. Further high-level studies involving randomized, controlled, clinical trials are warranted to confirm these results.ZusammenfassungZielSelbstligierende Brackets (SLBs) und konventionelle Brackets (CBs) wurden hinsichtlich transversaler Expansion Lückenschluss, Nivellierungseffizienz und Behandlungszeit verglichen.MethodenIn klinischen Datenbanken (MEDLINE, Cochrane Central Register of Controlled Trials, EMBASE, World Health Organization International Clinical Trials Registry Platform, Chinese Biomedical Literature Database, China National Knowledge Infrastructure) wurde nach sämtlichen bisher publizierten randomisierten, kontrollierten klinischen Studien (RCTs) zu SLBSs und CBs gesucht. Zudem wurden relevante Periodika händisch durchgesehen. Die Daten wurden von 2 Reviewern unabhängig extrahiert, das Bias-Risiko wurde mit dem entsprechenden Cochrane-Collaboration-Tool ermittelt und Diskrepanzen wurden mit einem dritten Reviewer bis zur Konsensfindung diskutiert. Die Metaanalysen wurden mit der Software RevMan (Version 5.3) durchgeführt.ErgebnisseInsgesamt 976 Patienten aus 17 RCTs wurden in die Studie aufgenommen, 11 RCTs eigneten sich für die quantitative Synthese, wobei bei zwei Studien ein geringes Bias-Risiko bestand. Metaanalysen zeigten, dass CBs hinsichtlich der Erweiterung der intercaninen Distanz im Unterkiefer überlegen waren. Passive SLBs dagegen waren effektiver bei der Expansion im Molarenbereich. Zudem zeigten sich CBs offensichtlich / scheinbar vorteilhaft bei kurzen Behandlungszeiten. Beim Lückenschluss unterschieden sich SLBs und CBs nicht.SchlussfolgerungenAuf der Basis der aktuell verfügbaren klinischen Evidenz aus RCTs zeigten SLBs im Vergleich zu CBs keine klinische Überlegenheit hinsichtlich transversaler Expansion, Lückenschluss bzw. kieferorthopädischer Effizienz. Zur Bestätigung dieser Ergebnisse bedarf es weiterer qualitativ hochwertiger Forschung einschließlich randomisierter, kontrollierter klinischer Studien.

YAP regulates periodontal ligament cell differentiation into myofibroblast interacted with RhoA/ROCK pathway: HE et al.

During orthodontic tooth movement (OTM), periodontal ligament cells (PDLCs) receive the mechanical stimuli and transform it into myofibroblasts (Mfbs). Indeed, previous studies have demonstrated that mechanical stimuli can promote the expression of Mfb marker α-smooth muscle actin (α-SMA) in PDLCs. Transforming growth factor β1 (TGF-β1), as the target gene of yes-associated protein (YAP), has been proven to be involved in this process. Here, we sought to assess the role of YAP in Mfbs differentiation from PDLCs. The time-course expression of YAP and α-SMA was manifested in OTM model in vivo as well as under tensional stimuli in vitro. Inhibition of RhoA/Rho-associated kinase (ROCK) pathway using Y27632 significantly reduced tension-induced Mfb differentiation and YAP expression. Moreover, overexpression of YAP with lentiviral transfection in PDLCs rescued the repression effect of Mfb differentiation induced by Y27632. These data together suggest a crucial role of YAP in regulating tension-induced Mfb differentiation from PDLC interacted with RhoA/ROCK pathway.