Oral microbiome contributes to the failure of orthodontic temporary anchorage devices (TADs).

BACKGROUND: The stability of temporary anchorage devices (TADs) is critical in orthodontic clinics. The failure of TADs is multifactorial, and the role of the oral microbiome has not been clearly defined. Herein, we attempted to analyze the contribution of the oral microbiome to the failure of TADs. METHODS: Next-generation sequencing was adopted for analyzing the microbiome on the TADs from orthodontic patients. 29 TADs (15 failed TADs and 14 successful TADs) were used for 16S rRNA gene sequencing. A total of 135 TADs (62 failed TADs and 73 successful TADs) were collected to conduct metagenomic sequencing. Additionally, 34 verified samples (18 failed TADs and 16 successful TADs) were collected for quantitative real-time polymerase chain reaction analysis (qRT-PCR). RESULTS: Successful and failed TADs demonstrated discrepancies in microbiome structure, composition, and function. Clear separations were found in ß-diversity in 16S rRNA gene sequencing as well as metagenomic sequencing (p < 0.05). Metagenomic sequencing showed that Prevotella intermedia, Eikenella corrodens, Parvimonas spp., Neisseria elongata, and Catonella morbi were enriched in the failed groups. qRT-PCR also demonstrated that the absolute bacteria load of Prevotella intermedia was higher in failed TADs (p < 0.05). Considering functional aspects, the failed group showed enriched genes involved in flagellar assembly, bacterial chemotaxis, and oxidative phosphorylation. CONCLUSIONS: This study illustrated the compositional and functional differences of microorganisms found on successful and failed TADs, indicating that controlling bacterial adhesion on the surface of TADs is essential for their success rate.

Molecular Phylogeny and Dating Reveal a Terrestrial Origin in the Early Carboniferous for Ascaridoid Nematodes.

Ascaridoids are among the commonest groups of zooparasitic nematodes (roundworms) and occur in the alimentary canal of all major vertebrate groups, including humans. They have an extremely high diversity and are of major socio-economic importance. However, their evolutionary history remains poorly known. Herein, we performed a comprehensive phylogenetic analysis of the Ascaridoidea. Our results divided the Ascaridoidea into six monophyletic major clades, i.e., the Heterocheilidae, Acanthocheilidae, Anisakidae, Ascarididae, Toxocaridae, and Raphidascarididae, among which the Heterocheilidae, rather than the Acanthocheilidae, represents the sister clade to the remaining ascaridoids. The phylogeny was calibrated using an approach that involves time priors from fossils of the co-evolving hosts, and dates the common ancestor of the Ascaridoidea back to the Early Carboniferous (approximately 360.47-325.27 Ma). The divergence dates and ancestral host types indicated by our study suggest that members of the Ascaridoidea first parasitized terrestrial tetrapods, and subsequently, extended their host range to elasmobranchs and teleosts. We also propose that the fundamental terrestrial-aquatic switches of these nematodes were affected by changes in sea-level during the Triassic to the Early Cretaceous.

Morphological study of Ophidascaris excavata Hsü & Hoeppli, 1931 (Ascaridida: Ascarididae) from Gloydius brevicaudus (Stejneger) (Reptilia: Viperidae).

Ophidascaris excavata Hsü & Hoeppli, 1931 is a poorly known ascaridid parasite reported from the short-tailed pit viper Gloydius brevicaudus (Stejneger) (Reptilia: Viperidae) in China. In the present paper, the detailed morphology of this nematode was studied using light and scanning electron microscopy (SEM) based on newly collected material. The results revealed several important, but previously unreported, morphological features, including the presence of one pair of small, finger-like prolongations on each lip, narrow cervical alae beginning well posterior to the base of the ventrolateral lips and the second pair of postcloacal ventro-lateral papillae being double; in addition, there is no intestinal caecum. These supplementary morphological and morphometric data, especially the detailed morphological features obtained herein under SEM, would help us to understand the relationships of O. excavata with its congeners and enable us to diagnose this species more accurately.

Dujardinascaris gigantea sp. n. (Nematoda: Ascaridida) from the critically endangered crocodile Alligator sinensis Fauvel (Reptilia: Crocodylia).

The Chinese alligator Alligator sinensis Fauvel (Reptilia: Crocodylia) is considered as one of the most critically endangered species of the 23 extant crocodiles. However, our knowledge of the helminth parasites of this rare animal is completely lacking. During a helminthological survey of reptiles in China, we found a new ascaridoid nematode, Dujardinascaris gigantea sp. n. from A. sinensis. The morphology of D. gigantea sp. n. was studied using light and scanning electron microscopy. The new species was also characterised using molecular methods by sequencing and analysing the small ribosomal DNA (18S) and the second internal transcribed spacer (ITS-2).

Porrocaecum parvum n. sp. and P. reticulatum (Linstow, 1899) (Nematoda: Ascaridoidea) from birds in China.

Porrocaecum parvum n. sp. is described from the grey-faced buzzard Butastur indicus (Gmelin) (Accipitriformes: Accipitridae) in China. The new species differs from its congeners in having well-developed cervical alae, small interlabia and very short intestinal caecum (0.34 mm long, representing 11.9% of oesophageal length) and in the number and arrangement of the caudal papillae (29 pairs in total, arranged as follows: 21 pairs precloacal, single double pair paracloacal and seven pairs postcloacal) and in the morphology of the male tail. In addition, Porrocaecum reticulatum (Linstow, 1899), collected from the purple heron Ardea purpurea L., the grey heron A. cinerea L. and the little egret Egretta garzetta (L.) (Pelecaniformes: Ardeidae) in China, was also studied using light and, for the first time, scanning electron microscopy. Previously unreported and erroneous morphological features of taxonomic significance are revealed, including the presence of narrow cervical alae, single pair of small, submedial pores and single, short medial ditch on each lip, interlabia with very pointed anterior prolongation, single medio-ventral precloacal papilla on anterior cloacal lip and double paracloacal papillae slightly posterior to cloaca.

Morphology, ultrastructure and molecular characterisation of Spiroxys japonica Morishita, 1926 (Spirurida: Gnathostomatidae) from Pelophylax nigromaculatus (Hallowell) (Amphibia: Ranidae).

Gnathostomatid nematodes identified morphologically as Spiroxys japonica Morishita, 1926 were collected from the dark-spotted frog Pelophylax nigromaculatus (Hallowell) (Amphibia: Ranidae) in China. Light and scanning electron microscopy were used to study the morphology of this species in detail. Previously unreported morphological features are revealed and others corrected. In addition, adult nematodes of S. japonica collected from P. nigromaculatus and Spiroxys hanzaki Hasegawa, Miyata & Doi, 1998 collected from Andrias japonicus (Temminck) (Caudata: Cryptobranchidae) in China and Japan, respectively, and the third-stage larva of S. japonica collected from Lithobates catesbeianus (Shaw) (Anura: Ranidae) in Japan, were characterised using molecular methods by sequencing and analysing ribosomal [large ribosomal DNA (18S) and internal transcribed space] and mitochondrial [cytochrome c oxidase subunit 1] target regions, respectively. The new morphological and genetic data contributes to a more accurate diagnosis of this hitherto little known nematode genus.

Occurrence of Hysterothylacium and Anisakis nematodes (Ascaridida: Ascaridoidea) in the tanaka's snailfish Liparis tanakae (Gilbert & Burke) (Scorpaeniformes: Liparidae).

The tanaka's snailfish Liparis tanakae (Gilbert & Burke) (Scorpaeniformes: Liparidae) is an economically important marine fish species in China. However, the helminth parasites of this fish are still poorly known. During a helminthological survey of Chinese marine fishes from 2011 to 2012, we revealed that L. tanakae was heavily infected with third-stage larvae and adults of ascaridoid nematodes (total prevalence 100% and mean intensity 82.3 nematodes per fish). Four species of third-stage larvae Hysterothylacium liparis Li, Xu & Zhang, 2007, H. aduncum (Rudolphi, 1802), Hysterothylacium fabri (Rudolphi, 1819), and Anisakis pegreffii (Campana-Rouget & Biocca, 1955) and a single species of adults H. liparis were differentiated and identified by morphological and molecular methods. The detailed morphology of the four species of third-stage larvae was also studied using light microscopy and scanning electron microscopy. The morphological and molecular characterization of the third-stage larvae of H. liparis was reported. Liparis tanakae represents a new host record for A. pegreffii and H. fabri. In addition, a new name, Hysterothylacium zhoushanense nom. nov. was also given to Hysterothylacium zhoushanensis Li, Liu & Zhang, 2012 to make the latinized specific epithet agree with this neuter generic name.

Ophidascaris wangi sp. n. and O. najae (Gedoelst, 1916) (Ascaridida: Ascaridoidea) from snakes in China.

Ophidascaris wangi sp. n. collected from the king rat snake Elaphe carinata (Günther) (Serpentes: Colubridae) in China is described using both light and scanning electron microscopy. The new species differs from its congeners in the presence of narrow lateral alae originating a short distance posterior to the base of the ventrolateral lips, its relatively long oesophagus (3.57-4.54 mm long, representing 6.6-7.6% of body length), its short spicules (1.89-2.14 mm long, representing 3.9-4.3% of body length), the number and arrangement of caudal papillae (49-57 pairs in total, arranged as follows: 43-51 pairs precloacal, 2 pairs joined paracloacal and 4 pairs postcloacal), the presence of a particular papilliform medioventral, postcloacal ornamentation and the morphology of the eggs and tip of the female tail. In addition, Ophidascaris najae (Gedoelst, 1916), collected from the king cobra Ophiophagus hannah Cantor (Serpentes: Elapidae) in China, is also redescribed. The morphology of the cervical papillae, labial denticles and phasmids of the female is described for the first time.

Morphological variability and molecular characterisation of Dichelyne (Cucullanellus) pleuronectidis (Yamaguti, 1935) (Ascaridida: Cucullanidae) from the flatfish Pleuronichthys cornutus (Temminck & Schlegel) (Pleuronectiformes: Pleuronectidae) in the East China Sea.

Cucullanid nematodes identified morphologically as Dichelyne (Cucullanellus) pleuronectidis (Yamaguti, 1935) were collected from the ridged-eye flounder Pleuronichthys cornutus (Temminck & Schlegel) (Pleuronectiformes: Pleuronectidae) in the East China Sea. Their examination using light microscopy and, for the first time, scanning electron microscopy, revealed several important, but previously unreported morphological features and the presence of remarkable morphological differences in the intestinal caecum and deirids among some individuals. Consequently, specimens of D. pleuronectidis were characterised using molecular methods by sequencing and analysing the internal transcribed spacer (ITS) of the ribosomal DNA to test whether the present material with broad range of morphological variability, represents a complex of sibling species or a single species. The results of molecular analyses proved that the differences in the intestinal ceacum and deirids should be considered as intraspecific variation and that the nematode material collected from P. cornutus in the East China Sea represented a single species, D. pleuronectidis. These new morphological and genetic data contributed to an accurate diagnosis of this hitherto insufficiently known nematode and also indicated that a more rigorous study based on morphological and genetic data with broader representation of the Cucullanidae is required to assess whether the traditionally used diagnostic character of absence or presence of intestinal ceacum is of generic importance in distinguishing Dichelyne and Cucullanus.

Effect of Residual Stress and Microstructure on the Fatigue Crack Growth Behavior of Aluminum Friction Stir Welded Joints.

Friction stir welding (FSW) has been adopted in the aerospace industry for fabricating structural alloys due to the low melting point and high thermal conductivity of aviation aluminum alloys. However, welding residual stresses can lead to secondary deformation in friction stir welded (FSWed) structures. Additionally, microstructural characteristics impact the crack growth rates and directions in these structures. Therefore, it is necessary to investigate the effects of residual stress and microstructure on the fatigue responses of FSWed joints. In this paper, we studied the fatigue crack growth behavior of two homogeneous and dissimilar FSWed joints with varying welding parameters, namely 2024-T3 and 7075-T6. The residual stresses were measured with the X-ray diffraction method. The dislocations and precipitates in different zones of the FSWed joints were analyzed via transmission electron microscopy (TEM). The results demonstrated that the residual stress significantly affected the fatigue crack growth rate and direction; the tensile residual stress promoted fatigue crack growth and offset the decrease in the fatigue crack growth rate that occurred due to grain refinement. The results of the microstructural analysis indicated that dislocation density and sliding resistance increased with the decrease in rotational speed and led to a decreased rate of fatigue crack propagation.

Quantitative evaluation of vertical control in orthodontic camouflage treatment for skeletal class II with hyperdivergent facial type.

BACKGROUND: In this study, we sought to quantify the influence of vertical control assisted by a temporary anchorage device (TAD) on orthodontic treatment efficacy for skeletal class II patients with a hyperdivergent facial type and probe into the critical factors of profile improvement. METHODS: A total of 36 adult patients with skeletal class II and a hyperdivergent facial type were included in this retrospective case-control study. To exclude the effect of sagittal anchorage reinforcement, the patients were divided into two groups: a maxillary maximum anchorage (MMA) group (N = 17), in which TADs were only used to help with anterior tooth retraction, and the MMA with vertical control (MMA + VC) group (N = 19), for which TADs were also used to intrude the maxillary molars and incisors. The treatment outcome was evaluated using dental, skeletal, and soft-tissue-related parameters via a cephalometric analysis and cast superimposition. RESULTS: A significant decrease in ANB (P < 0.05 for both groups), the retraction and uprighting of the maxillary and mandibular incisors, and the retraction of protruded upper and lower lips were observed in both groups. Moreover, a significant intrusion of the maxillary molars was observed via the cephalometric analysis (- 1.56 ± 1.52 mm, P < 0.05) and cast superimposition (- 2.25 ± 1.03 mm, P < 0.05) of the MMA + VC group but not the MMA group, which resulted in a remarkable decrease in the mandibular plane angle (- 1.82 ± 1.38°, P < 0.05). The Z angle (15.25 ± 5.30°, P < 0.05) and Chin thickness (- 0.97 ± 0.45°, P < 0.05) also improved dramatically in the MMA + VC group, indicating a better profile and a relaxed mentalis. Multivariate regression showed that the improvement in the soft tissue was closely related to the counterclockwise rotation of the mandible plane (P < 0.05). CONCLUSIONS: TAD-assisted vertical control can achieve intrusion of approximately 2 mm for the upper first molars and induce mandibular counterclockwise rotation of approximately 1.8°. Moreover, it is especially important for patients without sufficient retraction of the upper incisors or a satisfactory chin shape.

Effects of orthodontic camouflage treatment vs orthodontic-orthognathic surgical treatment on condylar stability in Class II hyperdivergent patients with severe temporomandibular joint osteoarthrosis: a retrospective observational study.

OBJECTIVES: To investigate the differences in profile changes and stability of the condyles between orthodontic camouflage treatment assisted by vertical control and that accomplished via orthognathic surgery in Class II hyperdivergent patients with TMJ osteoarthrosis (TMJOA). MATERIALS AND METHODS: This study included 27 Class II hyperdivergent TMJOA patients (54 condyles) who received orthodontic camouflage treatment (13 patients) or orthognathic surgery (14 patients) Cone-beam computerized tomography (CBCT) scans were taken before treatment (T1) and 1 year after treatment (T2). Cephalometric and TMJ measurement analyses were conducted to evaluate the change in profile and condyles from T1 to T2 using independent samples t-test and paired t-test. Three-dimensional (3D) deviation analysis was also performed to evaluate the stability of condyles from T1 to T2. RESULTS: Both groups showed significant profile improvement from T1 to T2. The changes in Z angle and ANB angle were larger in the surgical group than in the orthodontic group. Condylar width, length, and height remained stable after treatment in the orthodontic group (P > .05), while they reduced by 0.67 ± 0.85 mm, 1.14 ± 1.10 mm, and 1.07 ± 1.34 mm, respectively, in the surgical group (P < .05). Superior, posterior, medial, and lateral joint spaces were significantly reduced in the orthodontic group (P < .05). 3D deviations intuitively showed that condylar bone in the orthodontic group was more stable than that in the surgical group. CONCLUSIONS: For Class II hyperdivergent patients with severe TMJOA, orthodontic camouflage treatment with vertical control can effectively maintain the stability of condyles while significantly improving the profile. Surgical treatment yields a better profile but may increase the risk of condyle resorption.

Analysis of oral microbiome on temporary anchorage devices under different periodontal conditions.

BACKGROUND: Temporary anchorage devices (TADs) are maximum anchorages that have been widely used in orthodontic treatment. The aim of the study was to uncover whether a history of periodontitis would influence microbiome colonization on the TAD surface. RESULTS: Patients were grouped by periodontal evaluations before the orthodontic treatment. Patients with healthy periodontal conditions were classified as the healthy group, and patients diagnosed with periodontitis stage II or even worse were classified as the periodontitis group. Scanning electron microscopy (SEM) was used to analyze the existence of biofilm on the surface of 4 TADs from the healthy group and 4 TADs from the periodontitis group. Fifteen TADs from the healthy group and 12 TADs from the periodontitis group were collected. The microorganisms on the surface of TADs were harvested and analyzed by 16S rRNA gene sequencing. α-diversity indices and ß-diversity indices were calculated. Wilcoxon's test was used to determine differences between genera, species as well as KEGG functions. SEM analysis revealed bacteria colonization on the surface of TADs from both groups. Principal coordinate analysis (PCoA) based on ß diversity revealed differential sample clusters depending on periodontal conditions (P < 0.01). When comparing specific genera, Fusobacterium, Porphyromonas, Saccharibacteria_(TM7)_[G-1], Dialister, Parvimonas, Fretibacterium, Treponema were more enriched in TADs in the periodontitis group. In the KEGG analysis, TADs in the periodontitis group demonstrated enriched microbial activities involved with translation, genetic information processing, metabolism, and cell motility. CONCLUSIONS: This analysis elucidated the difference in total composition and function of TADs oral microorganisms between patients periodontally healthy and with periodontitis.

Fast actuator and sensor fault estimation based on adaptive unknown input observer.

This study evaluates the robust fault estimation problem of systems with actuator and sensor faults though the simultaneous use of unknown input disturbances and measurement noise. Specifically, an augmented descriptor system is preliminarily developed by creating an augmented state consisting of system states and sensor faults. Next, a novel fast adaptive unknown input observer (FAUIO) is proposed for the system to enhance its fault estimation performance. The existence condition of the novel FAUIO is then introduced for linear time-invariant systems with unknown input disturbances. Furthermore, the proposed FAUIO is extended to a class of Lipschitz nonlinear systems with unknown input disturbances and measurement noise to investigate the robust fault estimation problem. Accordingly, an H∞ performance index is employed to attenuate the influence of disturbances on fault estimation. Moreover, the linear matrix inequality (LMI) technique is applied to solve the designed FAUIO. Finally, the effectiveness of the developed FAUIO is validated via the simulation of two examples.

Artificial potential function based spacecraft proximity maneuver 6-DOF control under multiple pyramid-type constraints.

This paper addresses the problem of spacecraft six degree of freedom (6-DOF) pose tracking control with collision avoidance and field of view (FOV) pyramid-type constraints during the autonomous proximity maneuver. The constraints are modeled as pyramid envelopes, which can better represent some real cases with less conservativeness comparing with commonly used cone-shaped model. A novel modeling method is proposed to describe the pyramid-type constraints in the dual-quaternion frame. Based on the specific geometric property of the pyramid constraints, a new convex artificial potential function (APF) with only one global minimum is designed, which incorporates the pose constraints into the control design procedure. Then, an integrated APF based control law is presented to simultaneously control the rotational and translational motion of the spacecraft without violating the pyramid constraints. The stability of the closed-loop system is demonstrated through the Lyapunov theory, and numerical simulation results are carried out to show the effectiveness of the proposed control law.

Similarities and differences of estrogen in the regulation of temporomandibular joint osteoarthritis and knee osteoarthritis.

BACKGROUND: Temporomandibular joint osteoarthritis (TMJOA) and knee osteoarthritis (knee OA) are two kinds of common osteoarthritis (OA) that are characterized by chronic degeneration of soft and hard tissues around joints. Their gender and age differences suggest that there are similarities and differences between the pathogenic mechanisms of TMJOA and knee OA. OBJECTIVE: To review recent studies on the effect of estrogen on TMJOA and knee OA, and summarize their possible pathogenesis and molecular mechanisms. SOURCES: Articles up to present reporting the relationship of estrogen and TMJOA or knee OA are included. An extensive electronic search was conducted of databases including PubMed, Web of science core collection. CONCLUSION: According to epidemiological investigations, TMJOA primarily happens to females of puberty and childbearing age, while knee OA mainly affects postmenopausal women. Epidemiological investigation and experimental research suggest that estrogen may have a different effect on TMJ and on knee. Though estrogen regulates TMJOA and knee OA via estrogen-related receptors (ERR), their pathogenesis and pathway of estrogen regulation are different. To find out the accurate regulation of estrogen on TMJOA and knee OA, specific pathways and molecular mechanisms still need further exploration.

Formation-containment control of multi-agent systems with communication delays.

This paper designs formation-containment control algorithms for a class of second-order nonlinear multi-agent systems governed by Euler-Lagrange dynamics with communication delays. The formation-containment problem consists of leader agents' formation control and follower agents' containment control. Firstly, to make the leaders form a desired formation and move collectively with a constant velocity, a coordinated formation control algorithm is designed and the variable-gain technique is used to eliminate the effect of communication delays on the leaders' formation control. Secondly, considering that only the leaders have access to the desired moving velocity, we propose distributed velocity estimators for followers in which the communication delays also exist in the followers' information interaction. By using the estimated velocity information, coordinated containment control laws are designed for the followers to drive them asymptotically converge to the convex hull spanned by all leaders. Furthermore, to increase the system robustness against uncertainties and external disturbances, the adaptive updating laws are designed for all agents. Finally, simulations are given to demonstrate these obtained results.

Microbiological Advances in Orthodontics: An Overview and Detailed Analysis of Temporary Anchorage Devices.

Dental biofilm is the initiating factor of oral diseases, such as periodontitis and caries. Orthodontic treatment could alter the microbiome structure balance, and increase the risk of such diseases. Furthermore, fixed appliances can induce temporary changes in the microbiome community, and the changes that clear aligners bring are smaller by comparison. Temporary anchorage devices (TADs) are skeletal anchorages that are widely used in orthodontic treatment. Microorganisms affect the occurrence and development of inflammation surrounding TADs. At present, existing researches have verified the existence of plaque biofilm on the surface of TADs, but the formation of plaque biofilm and plaque composition under different stable conditions have not been fully understood. The development of high-throughput sequencing, molecular biology experiments, and metabonomics have provided new research ideas to solve this problem. They can become an effective means to explore the microbiome surrounding TADs.

An Overview of Anterior Repositioning Splint Therapy for Disc Displacement-related Temporomandibular Disorders.

Anterior repositioning splint (ARS) therapy is considered one of the most effective therapies for treating disc displacement-related temporomandibular disorders (TMDs), which account for a large proportion of TMD cases. Owing to the wide application of this therapy, the exact mechanism of remission has increasingly drawn attention. Given that practitioners have different views on ARS therapy, its indications are broadened, and operating methods diverged. This review attempts to provide an overview of ARS therapy and helps practitioners establish indications and suitable operating methods. Representative views in the past 10 years were summarised, and conclusions were drawn as follows: The mechanism of ARS therapy is mainly attributed to internal derangement correction, improvement of stress distribution and recently reported joint remodeling. It has an evident effect in the short term, and the most prevalent operating methods are protruding the mandible to the edge-to-edge position and wearing the ARS for 24 hours daily for 3-6 months. However, long-term stability is not optimal, and thus indications should be selected carefully. Notably, most of the clinical studies in this field are case analyses with low-quality evidence. Well-designed RCTs are required to further validate relevant theories.