The RNA binding protein OsLa influences grain and anther development in rice.

La proteins are found widely in eukaryotes and play a variety of vital roles. AtLa1 has been identified as an La protein that is necessary for embryogenesis in Arabidopsis; however, the existence and biological functions of La proteins in rice (Oryza sativa L.) remain unclear. In this study, we identified and characterized two La proteins in rice that are homologous to AtLa1 and named them OsLa1 and OsLa2. Both the OsLa1 and OsLa2 genes encode RNA-binding proteins with an La domain and two RNA-binding domains. Mutant OsLa1 reduced grain length and pollen fertility, whereas OsLa1 overexpression caused the opposite phenotypes. Further experiments indicated that OsLa1 modulates grain size by influencing cell expansion. Interestingly, mutant OsLa2 resulted in thin grains with decreased weight and a low seed-setting rate. We also found that OsLa1 interacted with OsLa2 and that both OsLa1 and OsLa2 interacted with OseIF6.1, a eukaryotic translation initiation factor involved in ribosome biogenesis. In addition, OsLa1 was able to bind to OseIF6.1 mRNA to modulate its expression. Complete OseIF6.1 knockout caused lethality and OseIF6.1/oseif6.1 heterozygous plants displayed low fertility and low seed setting. Together, our results enrich our knowledge of the role of La proteins in rice growth and development, as well as the relationship between La and eIF6 in rice.

Upregulation of ROBO3 promotes proliferation, migration and adhesion of AML cells and affects the survival of AML patients.

Acute myeloid leukemia (AML) is a heterogeneous hematological malignancy, which is the most common and severe acute leukemia in adults. Its occurrence, development and prognosis are affected by many factors, and more research is still needed to further guide its treatment. Here, we found that roundabout3 (ROBO3) was associated with poor prognosis in AML through bioinformatics analysis. We then found that overexpression of ROBO3 promoted AML cell proliferation, adhesion and migration while knockdown of ROBO3 had opposite effects. We subsequently found that ROBO3 regulated CD34 expression in AML cells, and this regulatory effect may be achieved through the Hippo-YAP pathway. The inhibitors of this pathway, K-975 and verteporfin, showed an inhibitory effect on AML cells with high ROBO3 expression. ROBO3 was also found to be significantly increased in bone marrow samples from AML patients. Our research indicates that ROBO3 plays an important role in the development of AML, which suggests that ROBO3 can be a prognostic biomarker and potential therapeutic target for AML.

The effect of corticotomy on the compensatory remodeling of alveolar bone during orthodontic treatment.

BACKGROUND: This study aimed to explore whether compensatory remodeling of the alveolar bone surface occurred during the buccal palatal movement of orthodontic teeth. We preliminarily explored whether corticotomy could activate or accelerate osteogenesis in the alveolar bone surface by measuring the expression of TGF-ß1 (transforming growth factor-ß1), which can facilitate the proliferation and differentiation of osteoblasts and regulate the maturity and formation of bone. METHODS: Sixty 10-week-old male Wistar rats were selected. In the orthodontic group, 20 rats were implanted with a constriction device between the maxillary first molars under general anesthesia. In the corticotomy group, 20 rats were implanted with a constriction device, and a palatal incision was made to penetrate the cortical bone. In the control group, 20 rats underwent no experimental operation except general anesthesia. After 1, 3, 5 and 7 days, the maxillary first molars and the surrounding alveolar bone were harvested, and coronal sections containing the apical mesial buccal root were prepared and observed using tetracycline fluorescence, HE staining and immunohistochemical staining for TGF-ß1. Image-Pro Plus software was used to assess the immunohistochemical results, and SPSS 22.0 statistical software was used to analyze variance and perform the LSD test. RESULTS: The tetracycline fluorescence results showed that in the periosteum near the apical region, an obvious fluorescence signal was observed in the orthodontic group and the corticotomy group compared with the control group. In the orthodontic group and corticotomy group, HE staining showed that the morphology was similar to cube-shaped. The immunohistochemical results showed that TGF-ß1 was significantly increased in the periosteum near the apical region in the orthodontic group and corticotomy group, and there were significant differences among the three groups. In addition, the expression of TGF-ß1 in the periosteum in the orthodontic group and the corticotomy group gradually increased over time, reaching a peak on day 5 and slightly decreasing on day 7. CONCLUSION: Osteogenesis occurred on the alveolar bone surface during the buccal palatal movement of orthodontic teeth, and corticotomy had a positive effect, and TGF-ß1 was involved in this process.

Accuracy of virtual surgical planning in segmental osteotomy in combination with bimaxillary orthognathic surgery with surgery first approach.

BACKGROUND: This study aimed to assess the accuracy of virtual surgical planning (VSP) in segmental osteotomy in combination with bimaxillary orthognathic surgery with surgery first approach (SFA) by means of three-dimensional (3D) measuring and superimposition, so as to promote the application of digital technology in combined orthodontic-orthognathic treatment. METHODS: 20 patients treated with segmental osteotomy in combination with bimaxillary orthognathic surgery with SFA from 2018 to 2020 were included. All of them acquired VSP performed by ProPlan CMF 3.0 software (Materialise Corporation, Belgium). The preoperative (T0) 3D model of VSP and the postoperative (T1) 3D model, reconstructed by the cone-beam computed tomography (CBCT) data acquired one week after surgery, were compared by measuring the 3D coordinates of the landmarks as well as 3D model superimposition for deviation analysis. The deviation analysis was achieved by Geomagic Studio 2013 (3D Systems Corporation, USA). The differences which represented the accuracy of VSP were evaluated by the root mean square deviation (RMSD) and the Bland-Altman method. RESULTS: There was no statistically significant difference between the 3D coordinates of T1 and T0 (P > 0.05), and the mean overall RMSD was 1.37 mm, within the clinical relevance of 2 mm. The RMSD of sagittal direction (1.76 mm) was greater than that of coronal and vertical directions (1.09 mm and 1.24 mm), and the RMSD of maxillary and mandibular aspects were basically equal (1.30 mm and 1.45 mm). The Bland-Altman method showed the T0 and T1 measurements were in good agreement. The mean RMSD obtained from the deviation analysis was 1.85 mm, within the clinical relevance. CONCLUSIONS: VSP in segmental osteotomy in combination with bimaxillary orthognathic surgery with SFA proved to acquire accurate outcome in this study.

l-cysteine desulfhydrase-related H2 S production is involved in OsSE5-promoted ammonium tolerance in roots of Oryza sativa.

Previous studies revealed that rice heme oxygenase PHOTOPERIOD SENSITIVITY 5 (OsSE5) is involved in the regulation of tolerance to excess ammonium by enhancing antioxidant defence. In this study, the relationship between OsSE5 and hydrogen sulfide (H2 S), a well-known signalling molecule, was investigated. Results showed that NH4 Cl triggered the induction of l-cysteine desulfhydrase (l-DES)-related H2 S production in rice seedling roots. A H2 S donor not only alleviated the excess ammonium-triggered inhibition of root growth but also reduced endogenous ammonium, both of which were aggravated by hypotaurine (HT, a H2 S scavenger) or dl-propargylglycine (PAG, a l-DES inhibitor). Nitrogen metabolism-related enzymes were activated by H2 S, thus resulting in the induction of amino acid synthesis and total nitrogen content. Interestingly, the activity of l-DES, as well as the enzymes involved in nitrogen metabolism, was significantly increased in the OsSE5-overexpression line (35S:OsSE5), whereas it impaired in the OsSE5-knockdown mutant (OsSE5-RNAi). The application of the HT/PAG or H2 S donor could differentially block or rescue NH4 Cl-hyposensitivity or hypersensitivity phenotypes in 35S:OsSE5-1 or OsSE5-RNAi-1 plants, with a concomitant modulation of nitrogen assimilation. Taken together, these results illustrated that H2 S function as an indispensable positive regulator participated in OsSE5-promoted ammonium tolerance, in which nitrogen metabolism was facilitated.

The Effect of Functional Mandibular Shift on the Muscle Spindle Systems in Head-Neck Muscles and the Related Neurotransmitter Histamine.

The aim of this study is to explore the effects of abnormal occlusion and functional recovery caused by functional mandible deviation on the head and neck muscles and muscle spindle sensory-motor system by electrophysiological response and endogenous monoamine neurotransmitters' distribution in the nucleus of the spinal tract. Seven-week-old male Wistar rats were randomly divided into 7 groups: normal control group, 2W experimental control group, 2W functional mandible deviation group, 2W functional mandible deviation recovery group, 4W experimental control group, 4W functional mandible deviation group, 4W functional mandible deviation recovery group. Chewing muscles, digastric muscle, splenius, and trapezius muscle spindles electrophysiological response activities at the opening and closing state were recorded. And then the chewing muscles, digastric, splenius, trapezius, and neck trigeminal nucleus were taken for histidine decarboxylase (HDC) detection by high performance liquid chromatography (HPLC), immunofluorescence, and reverse-transcription polymerase chain reaction (RT-PCR). Histamine receptor proteins in the neck nucleus of the spinal tract were also examined by immunofluorescence and RT-PCR. Electromyography activity of chewing muscles, digastric, and splenius muscle was significantly asymmetric; the abnormal muscle electromyography activity was mainly detected at the ipsilateral side. After functional mandibular deviation, muscle sensitivity on the ipsilateral sides of the chewing muscle and splenius decreased, muscle excitement weakened, modulation depth decreased, and the muscle spindle afferent impulses of excitation transmission speed slowed down. Changes for digastric muscle electrical activity were contrary. The functions recovered at different extents after removing the deflector. However, trapezius in all the experimental groups and recovery groups exhibited bilateral symmetry electrophysiological responses, and no significant difference compared with the control group. After functional mandibular deviation, HDC protein and messenger ribonucleic acid (mRNA) levels on the ipsilateral sides of the chewing muscle and splenius increased significantly. HDC level changes for digastric muscle were contrary. After the removal of the mandibular position deflector, HDC protein and mRNA levels decreased on the ipsilateral sides of the chewing muscle and splenius while they increased in the digastric muscle. The difference of histamine decarboxylase content in the bilateral trapezius in each experimental group was small. After functional mandibular deviation, the temporomandibular joint mechanical receptors not only caused the fusimotor fiber hypoallergenic fatigue slow response on the ipsilateral sides of splenius, but also increased the injury neurotransmitter histamine release. The authors' results further support the opinion that the temporomandibular joint receptors may be involved in the mechanical theory of the head and neck muscles nervous system regulation.

Role of Beclin-1-Mediated Autophagy in the Survival of Pediatric Leukemia Cells.

BACKGROUND/AIMS: Acute and chronic leukemia are severe malignant cancers worldwide, and can occur in pediatric patients. Since bone marrow cell transplantation is seriously limited by the availability of the immune-paired donor sources, the therapy for pediatric leukemia (PL) remains challenging. Autophagy is essential for the regulation of cell survival in the harsh environment. However, the role of autophagy in the survival of PL cells under the oxidative stress, e.g. chemotherapy, remain ill-defined. In the current study, we addressed these questions. METHODS: We analyzed the effects of oxidative stress on the cell viability of PL cells in vitro, using a CCK-8 assay. We analyzed the effects of oxidative stress on the apoptosis and autophagy of PL cells. We analyzed the levels of Beclin-1 and microRNA-93 (miR-93) in PL cells. Prediction of binding between miR-93 and 3'-UTR of Beclin-1 mRNA was performed by a bioinformatics algorithm and confirmed by a dual luciferase reporter assay. The relationship between levels of miR-93 and patients' survival was analyzed in PL patients. RESULTS: We found that oxidative stress dose-dependently increased autophagy in PL cells. While low-level oxidative stress did not increase apoptosis, high-level oxidative stress increased apoptosis, seemingly from failure of autophagy-mediated cell survival. High-level oxidative stress appeared to suppress the protein levels of an autophagy protein Beclin-1 in PL cells, possibly through induction of miR-93, which inhibited the translation of Beclin-1 mRNA via 3'-UTR binding. CONCLUSION: Beclin-1-mediated autophagy plays a key role in the survival of PL cells against oxidative stress. Induction of miR-93 may increase the sensitivity of PL cells to oxidative stress during chemotherapy to improve therapeutic outcome.

Prognostic significance of FLT3-ITD in pediatric acute myeloid leukemia: a meta-analysis of cohort studies.

The purpose of the study was to assess the effect of the internal tandem duplication in FMS-like tyrosine kinase 3 (FLT3-ITD) on the outcome in pediatric acute myeloid leukemia (AML) patients. We identified eligible studies from several databases including PubMed, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) (from January 1995 to July 2015). Ten studies of 1661 pediatric patients with AML were included in exploring the relationship between the FLT3-ITD and overall survival (OS)/event free survival (EFS). Pediatric patients with AML with FLT3-ITD had worse OS [HR = 2.19 (1.60-3.01)]/EFS [HR = 1.70 (1.37-2.11)] than those patients without FLT3-ITD. Furthermore, FLT3-ITD had unfavorable effect on OS/EFS in the subgroups of NOS, uni/multivariate model, number of patients, the length of following-up, and patient source. The findings of this meta-analysis indicated that FLT3-ITD had negative impact on pediatric patients with AML.

Association of ALOX5AP rs10507391/SG13S114 A>T polymorphism with cerebral infarction in the Chinese population: a meta-analysis study.

Various studies have investigated that the single nucleotide polymorphisms (SNPs) rs10507391/SG13S114 A>T polymorphism could increase the risk of cerebral infarction, however these results still remain controversial. Therefore we conducted a meta-analysis to estimate the association of the 5-lipoxygenase-activating protein gene (ALOX5AP) rs10507391/SG13S114 A > T polymorphism with the incidence of cerebral infarction in the Chinese population. Our researchers searched PubMed, Embase, Web of Science databases, China Biological Medicine Database (CBMD), Wanfang Chinese database, and the Chinese National Knowledge Infrastructure (CNKI) database. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were extracted and pooled to assess the strength of the association between the ALOX5AP rs10507391/SG13S114 A>T polymorphism and incidence of cerebral infarction. A total of 12 eligible studies including 6,844 cases and 7,850 controls based on the search criteria were involved in this meta-analysis. The distributions of genotypes in the cases and controls were all in agreement with Hardy-Weinberg equilibrium. We observed that the ALOX5AP rs10507391/SG13S114 A>T polymorphism carried with T allele contrast model, the homozygote codominant model, the heterozygote codominant model, the dominant model and the recessive model (all the models p > 0.05) had no risk of cerebral infarction when all studies were pooled into the meta-analysis. The results of the meta-analysis indicate that ALOX5AP rs10507391/SG13S114 A>T polymorphism is not associated with the risk of cerebral infarction in the Chinese population.

Rice OseIF6.1 encodes a eukaryotic translation initiation factor and is essential for the development of grain and anther.

The eIF6 proteins are distributed extensively in eukaryotes and play diverse and essential roles. The bona fide eIF6 protein in Arabidopsis, At-eIF6;1, is essential for embryogenesis. However, the role of eIF6 proteins in rice growth and development remains elusive and requires further investigation. Here, we characterized the functions of OseIF6.1, which is homologous to At-eIF6;1. OseIF6.1 encodes an eukaryotic translation initiation factor with a conserved eIF6 domain. The knockdown of OseIF6.1 resulted in a decrease in grain length and pollen sterility, whereas the overexpression of OseIF6.1 displayed opposite phenotypes. Further studies revealed that OseIF6.1 regulates grain shape by influencing cell expansion and proliferation. In addition, OseIF6.1 interacts with OsNMD3, which is a nuclear export adaptor for the 60S ribosomal subunit. The knockdown of OsNMD3 in plants exhibited reduced fertility and seed setting. Therefore, our findings have significantly enriched the current understanding of the role of OseIF6.1 in rice growth and development.

Vesicle trafficking in rice: too little is known.

The vesicle trafficking apparatus is a fundamental machinery to maintain the homeostasis of membrane-enclosed organelles in eukaryotic cells. Thus, it is broadly conserved in eukaryotes including plants. Intensive studies in the model organisms have produced a comprehensive picture of vesicle trafficking in yeast and human. However, with respect to the vesicle trafficking of plants including rice, our understanding of the components and their coordinated regulation is very limited. At present, several vesicle trafficking apparatus components and cargo proteins have been identified and characterized in rice, but there still remain large unknowns concerning the organization and function of the rice vesicle trafficking system. In this review, we outline the main vesicle trafficking pathways of rice based on knowledge obtained in model organisms, and summarize current advances of rice vesicle trafficking. We also propose to develop methodologies applicable to rice and even other crops for further exploring the mysteries of vesicle trafficking in plants.

Cognitive and neurochemical alterations in hyperhomocysteinemic rat.

Accumulating data have shown that the level of serum homocysteine in patients with mild cognitive impairment, vascular dementia and Alzheimer's disease is higher than normal while the underlying mechanism is not fully understood. Here, a hyperhomocysteinemic rat model was made by maintaining rats on a diet high in methionine. The cognitive behavior, level of monoamine neurotransmitters in brain homogenates and brain-derived neurotrophic factor (BDNF) in cerebral spinal fluid (CSF) were compared between high-methionine diet and control group. The high-methionine diet group presented longer mean latency of escape and lesser time in target quadrant in morris maze test, lower level of serotonin and dopamine in cortex homogenates and lower level of BDNF in CSF. Together, our findings provide evidence that hyperhomocysteinemia could cause alterations of monoamine and neurotrophic factor, which might be further pathogenetic mechanisms underlying the cognitive deterioration.

OsSIDP301, a Member of the DUF1644 Family, Negatively Regulates Salt Stress and Grain Size in Rice.

As a major environmental factor, salt stress substantially retards growth and reduces the productivity of rice (Oryza sativa). Members of the DUF1644 family, "the domains of unknown function 1644 motif" are predicted to play an essential regulatory role in response to abiotic stress. However, the specific molecular mechanisms of most members of this family remain elusive. Here, we report that the OsSIDP301 (stress-induced DUF1644 protein) was induced by salt stress and abscisic acid (ABA). We found that overexpression of OsSIDP301 (OE) in plants conferred salt hypersensitivity and reduced grain size, whereas plants with OsSIDP301 RNA interference (RNAi) exhibited salt tolerance and increased grain size in rice. OsSIDP301 determines salt stress tolerance by modulating genes involved in the salt-response and ABA signaling pathways. Further studies suggest that OsSIDP301 regulates grain size by influencing cell expansion in spikelet hulls. Moreover, OsSIDP301 interacts with OsBUL1 COMPLEX1 (OsBC1), which positively regulates grain size in rice. Our findings reveal that OsSIDP301 functions as a negative regulator of salt stress and grain size, and repressing its expression represents a promising strategy for improving salt stress tolerance and yield in rice.

Design of nanoconstructs that exhibit enhanced hemostatic efficiency and bioabsorbability.

Hemorrhage is a prime cause of death in civilian and military traumatic injuries, whereby a significant proportion of death and complications occur prior to paramedic arrival and hospital resuscitation. Hence, it is crucial to develop hemostatic materials that are able to be applied by simple processes and allow control over bleeding by inducing rapid hemostasis, non-invasively, until subjects receive necessary medical care. This tutorial review discusses recent advances in synthesis and fabrication of degradable hemostatic nanomaterials and nanocomposites. Control of assembly and fine-tuning of composition of absorbable (i.e., degradable) hemostatic supramolecular structures and nanoconstructs have afforded the development of smart devices and scaffolds capable of efficiently controlling bleeding while degrading over time, thereby reducing surgical operation times and hospitalization duration. The nanoconstructs that are highlighted have demonstrated hemostatic efficiency pre-clinically in animal models, while also sharing characteristics of degradability, bioabsorbability and presence of nano-assemblies within their compositions.

miR-452-5p regulates the responsiveness of intestinal epithelial cells in inflammatory bowel disease through Mcl-1.

Inflammatory bowel diseases (IBDs) are chronic immune disorders that occur in the intestinal tract. Previous studies have revealed that intestinal epithelial cells (IECs) play critical roles in the development of IBDs, and therapies targeting IECs hold great potential for the treatment of IBDs. However, the roles of microRNAs (miRs) in the regulation of IEC properties and whether they can be used as targets for IEC regulation and IBD treatment are largely unknown. The aim of the present study was to investigate the role of the miR-452-5p/Mcl-1 axis in the regulation of the properties of IECs during the pathology of IBD. A dextran sulfate sodium-induced mouse model of ulcerative colitis (UC) and an in vitro lipopolysaccharide-stimulated IEC-6 cell model were investigated. The results revealed that miR-452-5p expression in the IECs of the mice increased significantly upon UC induction, and the knockdown of miR-452-5p alleviated the IBD symptoms. Furthermore, the suppression of miR-452-5p downregulated the expression of the inflammatory cytokines IL-6, IL-8 and TNFα, and upregulated the expression of intestinal barrier-associated molecules, namely occludin, zona occludens 1 and mucin-2 in IECs in vitro and in vivo. Notably, the results indicated that miR-452-5p modulated the responses of IECs by negatively regulating the expression of Mcl-1, as the knockdown of Mcl-1 abrogated the effects of miR-452-5p suppression on IECs. The present study suggested that miR-452-5p regulated the responsiveness of IECs to influence the development of UC in an Mcl-1-dependent manner. These observations provide important information to improve the understanding of IBD pathogenesis and indicate that targeting the miR-452-5p-Mcl-1 signaling axis in IECs holds potential for IBD treatment.

Dehiscence and fenestration in anterior teeth : Comparison before and after orthodontic treatment.

BACKGROUND: Previous studies have reported incidence rates of dehiscence (DEH) and fenestration (FEN) as high as 36.51 and 51.09%, respectively. Only a few studies comparing DEH and FEN before and after orthodontic treatment (OT) are available in the literature. PURPOSE: The aim of this study was to evaluate the occurrence of DEH and FEN in anterior teeth, before and after OT, using cone-beam computed tomography (CBCT). In addition, findings may provide a clinical basis for avoiding DEH and FEN during therapeutic tooth alignment. PATIENTS AND METHODS: CBCT images of 21 patients near the end of their peak growth and development were included. DEH and FEN in the anterior teeth and thicknesses of the alveolar bone at the palatal (TP) and labiolingual (LL) sides of each anterior tooth were measured before and after OT. RESULTS: After OT, the incidence rates of mandibular anterior labial DEH, maxillary anterior TP-bone defect, and mandibular anterior lingual bone defect were increased by 20, 19, and 30%, respectively. Assessment of CT images prior to treatment showed that the teeth developing bone defects were significantly different regarding the apical alveolar bone thicknesses compared to the teeth that did not develop bone defects after OT, i.e., the incidence of DEH and FEN after OT was lower if the thickness of the apex to labiolingual alveolar bone before OT was as follows: the apex to labial alveolar bone thickness of the maxillary central incisor and maxillary lateral incisor was >4 mm, the apex to palatal alveolar bone thickness of the maxillary lateral incisor was >3 mm; the apex to labiolingual alveolar bone thickness of the lower incisor was >5 mm. CONCLUSION: The incidence of post-OT DEH at the maxillary anterior and mandibular anterior lingual surfaces were increased significantly compared to before treatment. In general, the smaller the apex to labiolingual alveolar bone thickness, the greater the likelihood of bone defects occurring after OT. Evaluation of the apical position of anterior teeth in alveolar bone can help minimize the occurrence of bone defects after OT.

[Comparison of root resorption between self-ligating and conventional brackets using cone-beam CT].

PURPOSE: To analyze the differences of root resorption between passive self-ligating and conventional brackets, and to determine the relationship between passive self-ligating brackets and root resorption. METHODS: Fifty patients were randomly divided into 2 groups using passive self-ligating brackets or conventional straight wire brackets (0.022 system), respectively. Cone-beam CT was taken before and after treatment. The amount of external apical root resorption of maxillary incisors was measured on CBCT images. Student's t test was performed to analyze the differences of root apical resorption between the 2 groups with SPSS17.0 software package. RESULTS: No significant difference(P> 0.05) in root resorption of maxillary incisors was found between passive self-ligating brackets and conventional brackets. CONCLUSIONS: Passive self-ligating brackets and conventional brackets can cause root resorption, but the difference was not significant. Passive self-ligating brackets do not induce more root resorption.

Integrated three-dimensional digital assessment of accuracy of anterior tooth movement using clear aligners.

OBJECTIVE: To assess the accuracy of anterior tooth movement using clear aligners in integrated three-dimensional digital models. METHODS: Cone-beam computed tomography was performed before and after treatment with clear aligners in 32 patients. Plaster casts were laser-scanned for virtual setup and aligner fabrication. Differences in predicted and achieved root and crown positions of anterior teeth were compared on superimposed maxillofacial digital images and virtual models and analyzed by Student's t-test. RESULTS: The mean discrepancies in maxillary and mandibular crown positions were 0.376 ± 0.041 mm and 0.398 ± 0.037 mm, respectively. Maxillary and mandibular root positions differed by 2.062 ± 0.128 mm and 1.941 ± 0.154 mm, respectively. CONCLUSIONS: Crowns but not roots of anterior teeth can be moved to designated positions using clear aligners, because these appliances cause tooth movement by tilting motion.

[Bond strengths of customized titanium brackets manufactured by selective laser melting].

OBJECTIVE: To investigate the bond strengths of customized titanium bracket manufactured by selective laser melting. METHODS: Eighty human premolars which had been extracted for orthodontic purpose were collected and divided randomly (by random table) into two groups (customized bracket group and 3M bracket group, 40 molars in each group). The 35% phosphoric acid was used for etching and the brackets were bonded with 3M Unitek bonding adhesive. All bonded specimens were placed in saline for 24 hours at room temperature and were tested on DWD3050 electronic testing machine to determine the shear bond strength and tensile bond strength. After debonding, the adhesive remnant indexes (ARI) were recorded. RESULTS: The shear bond strengths of customized brackets was 6.80 (6.20, 8.32) MPa, which was significantly lower than that of the 3M brackets [10.46 (9.72, 11.48) MPa] (Z = -3.463, P < 0.05). And the tensile bond strengths of customized brackets was (6.93 ± 1.21) MPa, which was significantly higher than that of the 3M brackets [(5.88 ± 1.23) MPa] (t = 2.81, P < 0.05). No significant difference was found in the ARI between two different kinds of the brackets. CONCLUSIONS: The shear bond strength and tensile bond strength of both kinds of brackets were enough for clinic application.