Chaoran Xue

Dental, skeletal asymmetries and functional characteristics in Class II subdivision malocclusions

Treatment outcomes of Angle Class II subdivision malocclusions may be compromised because of the uncertainty of the aetiology. Previous studies have reported controversial ideas about the origins, but the existence of a primary contributor still remains unknown. Functional factors have been mentioned as a probable cause, but until now, there have been no supporting data. This study was a cross-sectional investigation of the characteristics of Angle Class II subdivision malocclusion, including dental, skeletal and functional factors, by comparison of the subdivision group and the normal occlusion group. The evaluations of dental and skeletal asymmetries of both groups were carried out by cone-beam computed tomography (CBCT) and analysis of dental casts. The functional deviations were evaluated by cast mounting and measuring. In the subdivision group, the asymmetric position of the glenoid fossa was found to be the most significant skeletal asymmetry. No dentoalveolar asymmetry was found in this group. The most important finding was that, in subdivision malocclusions, functional deviation resulting in pseudoasymmetry occurred in 32.86% of the study participants. This deviation is probably related to the disharmonious arch width between maxillary and mandibular dental arches in the premolar section. The origin of Angle Class II subdivision malocclusion is multifactorial, with dental, skeletal and functional factors included. Functional deviation occurs, probably due to dental arch width disharmony. Asymmetric position of the glenoid fossa may account for most of the skeletal asymmetry.

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.

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).

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.

Surgical guide and CAD/CAM prebent titanium plate for sagittal split ramus osteotomy in the correction of mandibular prognathism

This study was designed to introduce and evaluate the clinical use of a surgical guide and a CAD/CAM prebent titanium plate for sagittal split ramus osteotomy (SSRO) in the correction of mandibular prognathism. We studied 14 patients who had been diagnosed, and treated by bilateral SSRO with the guide, during the period July 2015-January 2016. Surface deviations of distal segments from simulation until the end of the operation were measured on a coloured map. Deviations of position and orientation of the condyle and proximal segment from before to after operation, and those from simulation until the end of the operation, were measured with a 3-dimensional vector. All patients were followed up for at least a year. The coloured map showed that the mean (SD) distances were 0.40 (0.25)mm between the simulated and postoperative distal segments. The 3-dimensional vector showed that the mean values of mediolateral, anteroposterior, and superior-inferior translations of the condyles were less than 1mm (p<0.02) from before the operation until the end, and from simulation to the end of the operation, and the mean value of pitching for proximal segments was less than 1° (p<0.02) from simulation to the end of the operation. At the one year follow-up, the occlusions were stable. Based on accurate diagnosis and simulation, this guide takes the distal segment precisely to its planned position, and the condyle and proximal segment are well-controlled. This is a useful tool, which is comparatively easy to make and operate.

Wnt3α and transforming growth factor-β induce myofibroblast differentiation from periodontal ligament cells via different pathways

ABSTRACT Myofibroblasts are specialized cells that play a key role in connective tissue remodeling and reconstruction. Alpha‐smooth muscle actin (&agr;‐SMA), vimentin and tenascin‐C are myofibroblast phenotype, while &agr;‐SMA is the phenotypic marker. The observation that human periodontal ligament cells (hPDLCs) differentiate into myofibroblasts under orthodontic force has provided a new perspective for understanding of the biological and biomechanical mechanisms involved in orthodontic tooth movement. However, the cell‐specific molecular mechanisms leading to myofibroblast differentiation in the periodontal ligament (PDL) remain unclear. In this study, we found that expression of Wnt3&agr;, transforming growth factor‐&bgr;1 (TGF‐&bgr;1), &agr;‐SMA and tenascin‐C increased in both tension and compression regions of the PDL under orthodontic load compared with unloaded control, suggesting that upregulated Wnt3&agr; and TGF‐&bgr;1 signaling might have roles in myofibroblast differentiation in response to orthodontic force. We reveal in vitro that both Wnt3&agr; and TGF‐&bgr;1 promote myofibroblast differentiation from hPDLCs. Dickkopf‐1 (DKK1) impairs Wnt3&agr;‐induced myofibroblast differentiation in a &bgr;‐catenin‐dependent manner. TGF‐&bgr;1 stimulates myofibroblast differentiation via a JNK‐dependent mechanism. DKK1 has no significant effect on TGF‐&bgr;1‐induced myofibroblastic phenotype. HighlightsWnt3&agr;, TGF‐&bgr;1, &agr;‐SMA and tenascin‐C expressions increase in the periodontal ligament under load.Wnt3&agr; and TGF‐&bgr;1 promote myofibroblast differentiation from periodontal ligament cells.DKK1 impairs Wnt3&agr;‐induced myofibroblast differentiation in a &bgr;‐catenin‐dependent manner.TGF‐&bgr;1 stimulates myofibroblast differentiation via a JNK‐dependent mechanism.DKK1 has no significant effect on TGF‐&bgr;1‐induced myofibroblastic phenotype.

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.

Precise control of maxillary multidirectional movement in Le Fort I osteotomy using a surgical guiding device

We introduced a surgical protocol to achieve accurate maxillary multidirectional movement in Le Fort I osteotomies. This comprised a way of controlling precision and a guiding device together with prebent titanium plates. We evaluated the protocol using a semiautomated 3-dimensional assessment in 22 patients with maxillary multidirectional movement (movement in three or more of six directions). Operations were all done between October 2015 and April 2017 by the same surgeon, who followed the protocol strictly. To evaluate the accuracy, we measured the deviation of the orientation of landmarks and of the upper dentition. All cases were followed up for at least a year. They all involved maxillary movement in at least three directions, and nine involved movement in six. The guiding device was used intraoperatively in all cases. Vertical deviation of the segments of bone was often detected during removal of bone, and sagittal deviation in three cases, but we found no transverse deviations. The assessment of accuracy showed that the mediolateral, anteroposterior, and superoinferior translations of landmarks were all less than 1mm, with mean values of 0.29, 0.43, and 0.39mm, respectively. The pitch, roll, and yaw of the upper dentition were also less than 1°, with mean values of 0.60°, 0.35°, 0.36°, respectively. The proposed protocol allowed accurate reposition of the maxilla with multidirectional movement during Le Fort I osteotomy.

Transversal changes, space closure, and efficiency of conventional and self-ligating appliancesTransversale Veränderungen, Lückenschluss und Wirksamkeit von selbstligierenden vs. konventionellen Brackets

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.