Periodontitis (PD) may affect temporomandibular joint disorders (TMD) and TMD may influence PD in previous observational studies. Nevertheless, these studies were prone to confounders and reverse ...causation, leading to incorrect conclusions about causality and direction of association. This research investigates the associations between PD and TMD employing bidirectional two-sample Mendelian randomization (MR) analysis.
Single-nucleotide polymorphisms (SNPs) related to PD (p < 5 × 10
) were selected from a genome-wide association study (GWAS) from the Gene-Lifestyle Interaction in the Dental Endpoints (GLIDE) consortium, and related these to SNPs from FinnGen and UK Biobank (UKB) consortia, and vice versa. We implemented the standard inverse variance weighted (IVW), weighted median (WM), MR-Egger regression, and MR-PRESSO methods to estimate the potential causality between PD and TMD. Sensitive tests were conducted using robust MR methods. Results from FinnGen and UKB were combined using the fixed model.
PD did not appear to causally affect TMD. Additionally, the reverse MR analysis did not reveal a significant causal effect of TMD on PD. The results of other MR methods were similar to those of the IVW method. Sensitivity analyses addressed no potential pleiotropy in MR estimations. Results from the meta-analysis were consistent with the above-mentioned consequences.
This research does not support a causal relationship between PD and TMD. PD does not appear to worsen TMD directly, and vice versa.
Correction: Arthritis Res Ther 25, 143 (2023) https://doi.org/10.1186/s13075-023-03129-0 Following publication of the original article 1, the authors reported an error under heading Introduction. Is ...there an association between multiple sclerosis and oral health? Min Hu 1,2 Show authors Arthritis Research & Therapy volume 25, Article number: 208 (2023) Cite this article 160 Accesses Metrics details The Original Article was published on 08 August 2023 Correction: Arthritis Res Ther 25, 143 (2023) https://doi.org/10.1186/s13075-023-03129-0 Following publication of the original article 1, the authors reported an error under heading Introduction. Is there an association between multiple sclerosis and oral health?
Background The association between psychiatric disorders and dentofacial deformities has attracted widespread attention. However, their relationship is currently unclear and controversial. Methods A ...two-sample bidirectional MR analysis was performed to study the causal relationship between dentofacial deformity and eight psychiatric disorders, including major depressive disorder, panic disorder, schizophrenia, bipolar disorder, attention deficit hyperactivity disorder, Alzheimer’s disease, autism spectrum disorder, and neuroticism. Inverse variance weighted, weighted median, MR-Egger regression, weighted mode four methods, and further sensitivity analyses were conducted. Results The major depressive disorder affected dentofacial deformity, with an OR = 1.387 (95% CI = 1.181-1.629, P = 6.77×10 -5 ). No other psychiatric disorders were found to be associated with dentofacial deformity. In turn, dentofacial deformity were associated with neuroticism, with an OR = 1.050 (95% CI = 1.008-1.093, P = 0.018). And there was no evidence that dentofacial deformity would increase the risk of other psychiatric disorders. Conclusions Major depressive disorder might elevate the risk of dentofacial deformities, and dentofacial deformity conditions would increase the risk of the incidence of neuroticism.
Upregulation of Nell-1 has been associated with craniosynostosis (CS) in humans, and validated in a mouse transgenic Nell-1 overexpression model. Global Nell-1 inactivation in mice by ...N-ethyl-N-nitrosourea (ENU) mutagenesis results in neonatal lethality with skeletal abnormalities including cleidocranial dysplasia (CCD)-like calvarial bone defects. This study further defines the role of Nell-1 in craniofacial skeletogenesis by investigating specific inactivation of Nell-1 in Wnt1 expressing cell lineages due to the importance of cranial neural crest cells (CNCCs) in craniofacial tissue development. Nell-1
; Wnt1-Cre (Nell-1
KO) mice were generated for comprehensive analysis, while the relevant reporter mice were created for CNCC lineage tracing. Nell-1
KO mice were born alive, but revealed significant frontonasal and mandibular bone defects with complete penetrance. Immunostaining demonstrated that the affected craniofacial bones exhibited decreased osteogenic and Wnt/β-catenin markers (Osteocalcin and active-β-catenin). Nell-1-deficient CNCCs demonstrated a significant reduction in cell proliferation and osteogenic differentiation. Active-β-catenin levels were significantly low in Nell-1-deficient CNCCs, but were rescued along with osteogenic capacity to a level close to that of wild-type (WT) cells via exogenous Nell-1 protein. Surprisingly, 5.4% of young adult Nell-1
KO mice developed hydrocephalus with premature ossification of the intrasphenoidal synchondrosis and widened frontal, sagittal, and coronal sutures. Furthermore, the epithelial cells of the choroid plexus and ependymal cells exhibited degenerative changes with misplaced expression of their respective markers, transthyretin and vimentin, as well as dysregulated Pit-2 expression in hydrocephalic Nell-1
KO mice. Nell-1
KO embryos at E9.5, 14.5, 17.5, and newborn mice did not exhibit hydrocephalic phenotypes grossly and/or histologically. Collectively, Nell-1 is a pivotal modulator of CNCCs that is essential for normal development and growth of the cranial vault and base, and mandibles partially via activating the Wnt/β-catenin pathway. Nell-1 may also be critically involved in regulating cerebrospinal fluid homeostasis and in the pathogenesis of postnatal hydrocephalus.
Extracellular elastin‐derived peptides (EDPs) accumulate in the aging brain and have been associated with vascular dementia and Alzheimer's disease (AD). The activation of inflammatory processes in ...glial cells with EDP treatment has received attention, but not in neurons. To properly understand EDPs' pathogenic significance, the impact on neuronal function and neuron–microglia crosstalk was explored further. Among the EDP molecules, Val‐Gly‐Val‐Ala‐Pro‐Gly (VGVAPG) is a typical repeating hexapeptide. Here, we observed that EDPs‐VGVAPG influenced neuronal survival and morphology in a dose‐dependent manner. High concentrations of VGVAPG induced synapse loss and microglia hyperactivation in vivo and in vitro. Following EDP incubation, galectin 3 (Gal‐3) released by neurons served as a chemokine, attracting microglial engulfment. Blocking Gal‐3 and EDP binding remedied synapse loss in neurons and phagocytosis in microglia. In response to the accumulation of EDPs, proteomics in matrix remodeling and cytoskeleton dynamics, such as a disintegrin and metalloproteinase (ADAM) family, were engaged. These findings in extracellular EDPs provided more evidence for the relationship between aging and neuron dysfunction, increasing the insight of neuroinflammatory responses and the development of new specialized extracellular matrix remolding‐targeted therapy options for dementia or other neurodegenerative disease.
Extracellular elastin fibers were degraded irreversibly in the aging brain, increasing sensitivity to stroke, vascular dementia, and Alzheimer's disease. The role of physiologically active elastin‐derived peptides (EDPs) in neurons is currently being studied. It was suggested that release and accumulation of EDPs lead to neuronal spine loss and microglial hyperactivation. Galectin (Gal‐3) secretion from stressed neurons was engaged in the neurons‐microglia crosstalk, which promoted microglia engulfment. Synapse loss and local neuroinflammatory processes would contribute to neurological symptoms associated with neurodegenerative disorders. Targeting extracellular matrix integrity provides a promising therapeutic strategy for neurodegenerative disease.
Objectives
Skeletal class II malocclusion is one of the most common malocclusions. Among the functional appliances for skeletal class II malocclusion, the Twin-Block appliance with a maxillary ...expander is effective in repositioning the mandible forward. In this study, we focused our efforts on investigating the effects of Twin-Block appliances with maxillary expanders on the upper airway in growing children with skeletal class II malocclusion by tracing and measuring lateral cephalograms after evaluating the consistency of three-dimensional CBCT data and two-dimensional lateral cephalogram data.
Materials and methods
A total of 102 patients ranging from 9 to 15 years old (11.37 ± 2.80, male/female ratio = 1:1) with skeletal class II malocclusion were selected to evaluate the consistency of CBCT data and lateral cephalogram data. The strongly and moderately correlated segments were then selected to study the effects of Twin-Block with a maxillary expander on the upper airway in 66 growing children with skeletal class II malocclusion (11.31 ± 1.23 years old, male/female ratio = 1:1) by lateral cephalograms.
Results
The results showed a strong significant correlation in the nasopharynx (
r
= 0.708) and moderate significant correlations in the overall upper airway (
r
= 0.641), palatopharynx (
r
= 0.553), and glossopharynx (
r
= 0.575) but a weak correlation in the hypopharynx (
r
= 0.323). The corresponding determination coefficient (
R
2
) was also determined by scatter plot analysis. Moreover, compared with the pretreatment data (T1), the total area of the upper airway and the areas of the nasopharynx, palatopharynx, and glossopharynx after functional treatment (T2) increased statistically and significantly.
Conclusions
Lateral cephalograms can reflect the volume of the nasopharynx and oropharynx in skeletal class II children to a certain extent, while Twin-Block appliances with maxillary expanders can widen the volume of the nasopharynx and oropharynx significantly.
Clinical relevance
The lateral cephalogram is reliable for analyzing the nasopharynx, palatopharynx, and glossopharynx in orthodontic clinical practice. Twin-Block appliances with maxillary expanders have a positive effect on skeletal class II patients with airway stenosis.
Objectives
After bonding brackets to the first deciduous molar in a 2 × 4 technique, a three-dimensional finite element analysis (3D FEA) is used to demonstrate the biomechanical changes in an ...orthodontic system. This study aims to opt for the appropriate type of orthodontic technology by analyzing and comparing the mechanical systems produced by two types of 2 × 4 techniques employing rocking-chair archwires.
Materials and methods
Herein, the maxilla and maxillary dentition are modeled by cone beam computed tomography (CBCT) and 3D FEA. Common clinically used 0.016-inch round archwires (material: titanium-molybdenum alloy and stainless-steel) and 0.018-inch round archwires (material: titanium-molybdenum alloy and stainless-steel) are bent into the shape of a rocking chair with a depth of 3 mm. The forces and moments applied to the brackets are transferred to the dentition to evaluate the biomechanical effects of the 2 × 4 technique after the bracket is bonded to the first deciduous molar.
Results
For the central incisor, the teeth-moving distance in all three directions increases with bracket bonding to the first deciduous molar applying the 0.016-inch rocking-chair archwire. For the lateral incisor, the tooth root moves toward the gingival side when using 0.016-inch and 0.018-inch archwires. Moreover, for the same archwire size, the lateral incisors move toward the gingival side by bonding the bracket to the first deciduous molar. After bonding a bracket to the first deciduous molar, using rocking-chair archwires of 0.016 inch or 0.018 inch, the buccal movement distance of the first molar crown increases in the X-axis direction. In the Y-axis and Z-axis directions, the modified 2 × 4 technique significantly increases the effect of backward-tipping compared with the traditional 2 × 4 technique.
Conclusions
In clinical practice, the modified 2 × 4 technique can be used to increase the movement distance of anterior teeth to a certain extent and accelerate the orthodontic teeth movement. Moreover, the modified 2 × 4 technique is better in anchorage conservation of the first molar than the traditional technique.
Clinical relevance
Although the traditional 2 × 4 technique is widely used in early orthodontic treatment, we found mucosal damage and abnormal archwire deformation might affect orthodontic treatment time and effect. The modified 2 × 4 technique is a novel approach that avoids these drawbacks and improves orthodontic treatment efficiency.
Contrasting models for internal and external locations of South China within the Nuna and Rodinia supercontinents can be resolved when the current lithotectonic associations of Mesoproterozoic and ...older rocks units that constitute the craton are redefined into four lithotectonic domains: Kongling, Kunming-Hainan, Wuyi, and Coastal. The Kongling and Kunming-Hainan domains are characterized by isolated Archean to early Paleoproterozoic rock units and events and crop out in northern and southern South China, respectively. The Kunming-Hainan Domain is preserved in three spatially separated regions at Kunming (southwestern South China), along the Ailaoshan shear zone, and within Hainan Island. Both domains were affected by late Paleoproterozoic tectonothermal events, indicating their likely juxtaposition by this time to form the proto-Yangtze Block. Late Paleoproterozoic and Mesoproterozoic sedimentary and igneous rock units developed on the proto-Yangtze Block, especially in its southern portions, and help link the rock units that formed along the shear zone at Ailaoshan and on Hainan Island into a single, spatially unified unit prior to Paleozoic to Cenozoic structural disaggregation and translation. The Wuyi Domain consists of late Paleoproterozoic rock units within a NE-SW trending, fault-bounded block in eastern South China. The Coastal Domain lies east of the Wuyi domain and is inferred to constitute a structurally separate block. Basement to the domain is not exposed, but zircon Hf model ages from Mesozoic granites suggest Mesoproterozoic basement at depth.
The Archean to Paleoproterozoic tectonothermal record of the Kongling and Kunming-Hainan domains corresponds closely with that of NW Laurentia, suggesting all were linked, probably in association with assembly and subsequent partial fragmentation of the Nuna supercontinent. Furthermore, the age and character of Mesoproterozoic magmatism and detrital zircon signature of sedimentary rocks in the proto-Yangtze Block matches well with western Laurentia and eastern Australia-Antarctica. In particular, the detrital zircon signature of late Paleoproterozoic to early Mesoproterozoic sedimentary units in the block (e.g. Dongchuan Group) share a similar age spectrum with the Wernecke Supergroup of northwest Laurentia. This, together with similarities in the type and age of Fe-Cu mineralization in the domain with that in eastern Australia-Antarctica, especially northeast Australia, suggests a location adjacent to northwest Laurentia, southern Siberia, and northeast Australia within the Nuna supercontinent.
The timing and character of late Paleoproterozoic magmatic activity in the Wuyi domain along with age of detrital zircons in associated sedimentary rocks matches the record of northern India. During rifting between Australia–Antarctica and Laurentia in the late Mesoproterozoic, the proto-Yangtze Block remained linked to northeast Australia. During accretionary orogenesis in the early Neoproterozoic, the proto-Yangtze Block assembled with the Wuyi Domain along the northern margin of India. The Coastal domain likely accreted at this time forming the South China Craton. Displacement of the Hainan and Ailaoshan assemblages from southwest of the Kunming assemblage likely occurred in the Cenozoic with the activation of the Ailaoshan-Red River fault system but could have begun in the early to mid-Paleozoic based on evidence for tectonothermal events in the Hainan assemblage.
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