Initial arch wires used in orthodontic treatment with fixed appliances.

BACKGROUND: Initial arch wires are the first arch wires inserted into fixed appliance at the beginning of orthodontic treatment. With a number of different types of orthodontic arch wires available for initial tooth alignment, it is important to understand which are most efficient and which cause the least amount of root resorption and pain during the initial aligning stage of treatment. This is the third update of a Cochrane review first published in 2010. OBJECTIVES: To assess the effects of initial arch wires for the alignment of teeth with fixed orthodontic braces, in terms of the rate of tooth alignment, amount of root resorption accompanying tooth movement, and intensity of pain experienced by patients during the initial alignment stage of treatment. SEARCH METHODS: We searched Cochrane Oral Health's Trials Register, CENTRAL, MEDLINE, Embase, and two ongoing trials registries on 4 July 2022. SELECTION CRITERIA: We included randomised controlled trials (RCTs) of different initial arch wires used to align teeth with fixed orthodontic braces. We included people with full-arch fixed orthodontic appliances on the upper arch, lower arch, or both arches. DATA COLLECTION AND ANALYSIS: Two independent review authors were responsible for study selection, data extraction, and assessment of risk of bias in included studies. We contacted corresponding authors of included studies to obtain missing information. We resolved disagreements by discussion between the review authors. Our main outcomes were alignment rate (movement of teeth in mm), root resorption, time to alignment, and intensity of pain measured on a 100-mm visual analogue scale (VAS). We pooled data from studies with similar interventions and outcomes using random-effects models. We reported mean differences (MDs) with 95% confidence intervals (CIs) for continuous data, risk ratios (RRs) with 95% CIs for dichotomous data, and alignment rate ratios with 95% CIs for time-to-event data. Two independent review authors assessed the certainty of evidence. We resolved disagreements by discussion between the review authors. MAIN RESULTS: We included 29 RCTs with 1915 participants (2581 arches) in this review. Studies were generally small (sample sizes ranged from 14 to 200 participants). Duration of follow-up varied between three days and six months. Eleven studies received funding, six received no funding, and 12 provided no information about funding sources. We judged eight studies at high risk of bias, nine at low risk, and 12 at unclear risk. We grouped the studies into six main comparisons. Multistrand stainless steel wires versus wires composed of other materials Six studies with 409 participants (545 arches) evaluated multistrand stainless steel (StSt) wires versus wires composed of other materials. We are very uncertain about the effect of multistrand StSt wires versus other wires on alignment rate (4 studies, 281 participants, 417 arches; very low-certainty evidence). There may be little to no difference between multistrand StSt wires and other wires in terms of intensity of pain (MD -2.68 mm, 95% CI -6.75 to 1.38; 2 studies, 127 participants, 127 arches; low-certainty evidence). Conventional nickel-titanium wires versus superelastic nickel-titanium wires Four studies with 266 participants (274 arches) evaluated conventional nickel-titanium (NiTi) wires versus superelastic NiTi wires. There may be little to no difference between the different wire types in terms of alignment rate (124 participants, 124 arches, 2 studies; low-certainty evidence) and intensity of pain (MD -0.29 mm, 95% CI -1.10 to 0.52; 2 studies, 142 participants, 150 arches; low-certainty evidence). Conventional nickel-titanium wires versus thermoelastic copper-nickel-titanium wires Three studies with 210 participants (210 arches) evaluated conventional Ni-Ti versus thermoelastic copper-nickel-titanium (CuNiTi) wires. We are very uncertain about the effects of the different arch wires on alignment rate (1 study, 66 participants, 66 arches; very low-certainty evidence). There may be little to no difference between conventional NiTi wires and thermoelastic CuNiTi wires in terms of time to alignment (alignment rate ratio 1.30, 95% CI 0.68 to 2.50; 1 study, 60 participants, 60 arches; low-certainty evidence). Superelastic nickel-titanium wires versus thermoelastic nickel-titanium wires Twelve studies with 703 participants (936 arches) evaluated superelastic NiTi versus thermoelastic NiTi wires. There may be little to no difference between superelastic NiTi wires and thermoelastic NiTi wires in alignment rate at four weeks (MD -0.28 mm, 95% CI 0.62 to 0.06; 5 studies, 183 participants, 183 arches; low-certainty evidence). We are very uncertain about the effects of the different wires on root resorption (2 studies, 52 participants, 312 teeth; very low-certainty evidence). Superelastic NiTi wires compared with thermoelastic NiTi wires may result in a slight increase in time to alignment (MD 0.5 months, 95% CI 0.21 to 0.79; 1 study, 32 participants, 32 arches; low-certainty evidence) but are probably associated with a slight increase in intensity of pain (MD 6.96 mm, 95% CI 1.82 to 12.10; 3 studies, 94 participants, 138 arches, moderate-certainty evidence). Single-strand superelastic nickel-titanium wires versus coaxial superelastic nickel-titanium wires Three studies with 104 participants (104 arches) evaluated single-strand superelastic NiTi versus coaxial superelastic NiTi wires. Use of single-strand superelastic NiTi wires compared with coaxial superelastic NiTi wires probably results in a slight reduction in alignment rate at four weeks (MD -2.64 mm, 95% CI -4.61 to -0.67; 2 studies, 64 participants, 64 arches, moderate-certainty evidence). Different sizes of nickel-titanium wires Two studies with 149 participants (232 arches) compared different types of NiTi wires. There may be little to no difference between different sizes of NiTi wires in terms of pain (low-certainty evidence). AUTHORS' CONCLUSIONS: Superelastic NiTi wires probably produce slightly more pain after one day than thermoelastic NiTi wires, and single-strand superelastic NiTi wires probably have a lower alignment rate over four weeks compared with coaxial superelastic NiTi wires. All other evidence on alignment rate, root resorption, time to alignment, and pain is of low or very low certainty in all comparisons. Therefore, there is insufficient evidence to determine whether any particular arch wire material or size is superior to any other. The findings of this review are imprecise and unreliable; well-designed larger studies are needed to give better estimates of the benefits and harms of different arch wires. Orthodontists should exercise caution when interpreting the findings of this review and be prepared to adapt their treatment plans based on individual patient needs.

Molecular mechanism in trigeminal nerve and treatment methods related to orthodontic pain.

BACKGROUND: Orthodontic treatment is the main treatment approach for malocclusion. Orthodontic pain is an inevitable undesirable adverse reaction during orthodontic treatment. It is reported orthodontic pain has become one of the most common reason that patients withdraw from orthodontic treatment. Therefore, understanding the underlying mechanism and finding treatment of orthodontic pain are in urgent need. AIMS: This article aims to sort out the mechanisms and treatments of orthodontic pain, hoping to provide some ideas for future orthodontic pain relief. MATERIALS: Tooth movement will cause local inflammation. Certain inflammatory factors and cytokines stimulating the trigeminal nerve and further generating pain perception, as well as drugs and molecular targeted therapy blocking nerve conduction pathways, will be reviewed in this article. METHOD: We review and summaries current studies related to molecular mechanisms and treatment approaches in orthodontic pain control. RESULTS: Orthodontics pain related influencing factors and molecular mechanisms has been introduced. Commonly used clinical methods in orthodontic pain control has been evaluated. DISCUSSION: With the clarification of more molecular mechanisms, the direction of orthodontic pain treatment will shift to targeted drugs.

A conserved klo-1-mpk-1 pathway regulates autophagy and modulates longevity in Caenorhabditis elegans.

There are six different longevity models in Caenorhabditis elegans. Previous studies have identified several convergence points, such as hlh-30, daf-16, and klf-3, required for lifespan extension in these longevity models. However, it is not clear whether there other such convergence points. In this study, based on analysis of transcriptome data, we found that the expression of klo-1/klotho was elevated in several longevity models. klo-1 was required for lifespan extension in the glp-1(e2141) and isp-1(qm150) mutants. klo-1 extended the lifespan of glp-1(e2141) and isp-1(qm150) worms by activating extracellular-signal-regulated kinase (ERK). In addition, klo-1 and mpk-1 (the homologous gene encoding ERK) regulated autophagy in glp-1(e2141) mutants, suggesting that klo-1 regulates lifespan by activating autophagy.

N/OFQ modulates orofacial pain induced by tooth movement through CGRP-dependent pathways.

BACKGROUND: Nociceptin/orphanin FQ (N/OFQ) has been revealed to play bidirectional roles in orofacial pain modulation. Calcitonin gene-related peptide (CGRP) is a well-known pro-nociceptive molecule that participates in the modulation of orofacial pain. We aimed to determine the effects of N/OFQ on the modulation of orofacial pain and on the release of CGRP. METHODS: Orofacial pain model was established by ligating springs between incisors and molars in rats for the simulation of tooth movement. The expression level of N/OFQ was determined and pain level was scored in response to orofacial pain. Both agonist and antagonist of N/OFQ receptor were administered to examine their effects on pain and the expression of CGRP in trigeminal ganglia (TG). Moreover, gene therapy based on the overexpression of N/OFQ was delivered to validate the modulatory role of N/OFQ on pain and CGRP expression. RESULTS: Tooth movement elicited orofacial pain and an elevation in N/OFQ expression. N/OFQ exacerbated orofacial pain and upregulated CGRP expression in TG, while UFP-101 alleviated pain and downregulated CGRP expression. N/OFQ-based gene therapy was successful in overexpressing N/OFQ in TG, which resulted in pain exacerbation and elevation of CGRP expression in TG. CONCLUSIONS: N/OFQ exacerbated orofacial pain possibly through upregulating CGRP.

The Effects of Static Magnetic Field on Orthodontic Tooth Movement in Mice.

The application of static magnetic field (SMF) has been considered an effective and noninvasive method to accelerate orthodontic tooth movement. The objective of this study was to explore the effects of SMF on orthodontic tooth movement in mice. A total of 105 Balb/c mice (body mass: 25-30 g) were divided into experimental group (SMF + force, 48), control group (force only, 48), and blank group (neither SMF nor force, 9). After the placement of orthodontic appliances, the experimental group was exposed to the SMF environment generated by Neodymium-iron-boron (NdFeB) magnets with an intensity of 20-204 mT. At 1, 3, 7, 14, 21, and 28 days after appliance insertion, eight animals in both experimental and control groups were sacrificed and the left maxillae were dissected to measure the distance of tooth movement, respectively. Meanwhile, the width of periodontal ligament (PDL), length of hyalinized zone, and the number of osteoclasts were evaluated by hematoxylin-eosin and tartrate-resistant acid phosphatase staining. We finally found that the experimental group demonstrated an enhanced rate and greater cumulative amount of tooth movement than the control group (0.2887 ± 0.0041 mm vs. 0.2114 ± 0.0089 mm, P < 0.05). On Days 7, 14, and 28, the experimental group also displayed a significantly greater width of PDL. Earlier formation and removal of the hyalinized zone, and significantly more osteoclasts were observed in the experimental group as well. The results suggested that SMF may be a promising nonsurgical intervention to accelerate orthodontic tooth movement. © 2021 Bioelectromagnetics Society.

Study on the COVID-19 infection status, prevention and control strategies among people entering Shenzhen.

BACKGROUND: The novel coronavirus disease 2019 (COVID-19) confirmed cases overseas have continued to rise in the last months, and many people overseas have chosen to return to China. This increases the risk of a large number of imported cases which may cause a relapse of the COVID-19 outbreak. In order to prevent imported infection, the Shenzhen government has implemented a closed-loop management strategy using nucleic acid testing (NAT) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and requiring 14 days of medical observation for individuals with an overseas tour history (Hong Kong, Macao, Taiwan province and other countries). Our study aims to describe the status of COVID-19 infection among people entering Shenzhen, and to evaluate the effect of the closed-loop management strategy. METHODS: We undertook a descriptive study and risk analysis by the entry time, time of reporting, and local confirmed cases in countries of origin. The NAT were completed in Shenzhen Center for Disease Control and Prevention (CDC), ten district-level CDCs, and fever clinics. RESULTS: A total of 86,844 people from overseas entered Shenzhen from January 1 to April 18, 2020; there were 39 imported COVID cases and 293 close contacts. The infection rate of people entering was 4.49‰ [95% Confidence interval (CI): 3.26‰-6.05‰]. Fourteen imported cases (35.9%) came from the UK, and nine (23.08%) came from the USA. People entering from the USA since March 9 or from the UK since March 13 are the high-risk population. As of July 17, there have been no new confirmed cases in Shenzhen for 153 days, and the numbers of confirmed case, close contacts, and asymptomatic cases are 0. CONCLUSIONS: The closed-loop management has been effective in preventing imported infection and controlling domestic relapse. The distribution of entry time and report time for imported cases overseas was similar. This shows that it is important to implement closed-loop management at the port of entry.

Prediction of Self-Report Cognitive Function for the Symptomatic Remission in Schizophrenia Treated with Amisulpride: a Multicenter, 8-Week Case-Control Study.

This study aimed to determine whether self-report cognitive function is a predictor of symptomatic remission in amisulpride-treated schizophrenia. Patients with DSM-IV schizophrenia diagnoses who received amisulpride treatment, were recruited. Each patient received amisulpride with a flexible-dose strategy of 400-800 mg daily for eight weeks. Remission was defined by a shorter version of the Positive and Negative Symptom Scale(PANSS)criteria, which includes six items (PANSS-6) with scores of less than three in each item(criteria A) or total six scores of less than fourteen(criteria B). Three hundred and three patients completed the study in 15 hospitals in China. By criteria A, 244 (80.5%) achieved symptomatic remission at endpoint, and 258 (85.1%) by criteria B. Duration of illness (DOI) (criteria A: t = 2.31, P = 0.025,criteria B:t = 2.24,p = 0.026) and perceived deficits questionnaire at baseline (PDQ20 Day0) (criteria A: t = 3.32, P = 0.001,criteria B:t = 2.76,p = 0.006) in remission groups were less than that in non-remission groups. Logistic regression analysis took into account sex, age, age-onset, DOI, and PDQ20(Day0), and showed that PDQ20(Day0) was a predictor for symptomatic remission in criteria A (B = - 0.02, P = 0.014) and criteria B (B = - 0.03, P = 0.005). The odds ratio (OR) of achieving remission will be reduced by 2% in criteria A and 3% in criteria B. There were no significant differences in gender composition, age, BMI, education level, age-onset, a daily dose of amisulpride and the percentage of PDQ20 Improvement between remission and nonremission in criteria A or criteria B. Receiver operating characteristic(ROC) curves were found for PDQ20(Day0) to define the precise scores to predict remission of schizophrenia (criteria A:AUC = 0.614, S.E. = 0.041, 95% CI = 0.535-0.694, p = 0.007; criteria B:AUC = 0.633, S.E. = 0.045, 95% CI = 0.545-0.721, p = 0.005). Our data suggest that an early self-report cognitive function in amisulpride-treated schizophrenia is important in predicting for symptomatic remission, the fewer scores of PDQ20 at baseline mean the patients have less daily cognitive difficulty, the more likely the patient is to achieve symptomatic remission.

Comparison of pain perception, anxiety, and impacts on oral health-related quality of life between patients receiving clear aligners and fixed appliances during the initial stage of orthodontic treatment.

BACKGROUND AND OBJECTIVES: Clear aligner is an advanced orthodontic method with benefits of comfort, aesthetics, and convenience. This study aimed to compare pain perception, anxiety, and impacts on oral health-related quality of life (OHRQoL) between adult patients receiving clear aligners and fixed appliances during the initial stage of orthodontic treatments. MATERIAL AND METHODS: The two groups were well matched by ages, gender, and levels of malocclusion severity. Pain perception, anxiety, and OHRQoL were assessed through visual analogue scale, state-trait anxiety inventory, and oral health impact profile-14 (OHIP-14), respectively. And the comparison of above scores was performed by two-way analysis of variance. RESULTS: A total of 110 patients (55 pairs) were enrolled in this study. Orthodontic pain levels peaked on the first day and decreased gradually afterwards in both groups, which were significantly higher in the fixed group on the first, second, fourth, and fifth days. Likewise, anxiety levels peaked on the first day and decreased thereafter, with significant difference on the 1st, 3d, 5th, 7th, and 14th days. Moreover, the OHIP-14 scores increased and peaked on the first day and then gradually decreased for both groups, which were also significantly higher in the fixed group on the 1st, 7th, and 14th days. LIMITATIONS: More malocclusion types should be used for group matching. The effect of exclusion of small groups should be taken into consideration in sample size calculation. Income was significantly unbalanced between two groups due to higher cost of clear aligners, and random assignment of treatment modalities was unfeasible. CONCLUSIONS: Patients treated with clear aligners experienced lower pain levels, less anxiety, and higher OHRQoL as compared to those receiving fixed appliances.

Identification and evolutionary analysis of the nucleolar proteome of Giardia lamblia.

BACKGROUND: The nucleoli, including their proteomes, of higher eukaryotes have been extensively studied, while few studies about the nucleoli of the lower eukaryotes - protists were reported. Giardia lamblia, a protist with the controversy of whether it is an extreme primitive eukaryote or just a highly evolved parasite, might be an interesting object for carrying out the nucleolar proteome study of protists and for further examining the controversy. RESULTS: Using bioinformatics methods, we reconstructed G. lamblia nucleolar proteome (GiNuP) and the common nucleolar proteome of the three representative higher eukaryotes (human, Arabidopsis, yeast) (HEBNuP). Comparisons of the two proteomes revealed that: 1) GiNuP is much smaller than HEBNuP, but 78.4% of its proteins have orthologs in the latter; 2) More than 68% of the GiNuP proteins are involved in the "Ribosome related" function, and the others participate in the other functions, and these two groups of proteins are much larger and much smaller than those in HEBNuP, respectively; 3) Both GiNuP and HEBNuP have their own specific proteins, but HEBNuP has a much higher proportion of such proteins to participate in more categories of nucleolar functions. CONCLUSION: For the first time the nucleolar proteome of a protist - Giardia was reconstructed. The results of comparison of it with the common proteome of three representative higher eukaryotes -- HEBNuP indicated that the simplicity of GiNuP is most probably a reflection of primitiveness but not just parasitic reduction of Giardia, and simultaneously revealed some interesting evolutionary phenomena about the nucleolus and even the eukaryotic cell, compositionally and functionally.

Single-cell transcriptome sequencing of rumen ciliates provides insight into their molecular adaptations to the anaerobic and carbohydrate-rich rumen microenvironment.

Rumen ciliates are a specialized group of ciliates exclusively found in the anaerobic, carbohydrate-rich rumen microenvironment. However, the molecular and mechanistic basis of the physiological and behavioral adaptation of ciliates to the rumen microenvironment is undefined. We used single-cell transcriptome sequencing to explore the adaptive evolution of three rumen ciliates: two entodiniomorphids, Entodinium furca and Diplodinium dentatum; and one vestibuliferid, Isotricha intestinalis. We found that all three species are members of monophyletic orders within the class Litostomatea, with E. furca and D. dentatum in Entodiniomorphida and I. intestinalis in Vestibuliferida. The two entodiniomorphids might use H2-producing mitochondria and the vestibuliferid might use anaerobic mitochondria to survive under strictly anaerobic conditions. Moreover, carbohydrate-active enzyme (CAZyme) genes were identified in all three species, including cellulases, hemicellulases, and pectinases. The evidence that all three species have acquired prokaryote-derived genes by horizontal gene transfer (HGT) to digest plant biomass includes a significant enrichment of gene ontology categories such as cell wall macromolecule catabolic process and carbohydrate catabolic process and the identification of genes in common between CAZyme and HGT groups. These findings suggest that HGT might be an important mechanism in the adaptive evolution of ciliates to the rumen microenvironment.

Analysis of the association of TNF-α, IL-1A, and IL-1B polymorphisms with peri-implantitis in a Chinese non-smoking population.

OBJECTIVES: The purpose of this study was to investigate whether the genetic variations which could regulate inflammatory responses were associated with the risk of peri-implantitis. MATERIALS AND METHODS: We evaluated three genetic variants including tumor necrosis factor-alpha (TNF-α) - 308G/A, interleukin-1 alpha (IL-1A) - 889C/T, and IL-1 beta (IL-1B) + 3954C/T, as risk factors for peri-implantitis, in a total of 144 patients with peri-implantitis and 174 healthy controls in a Chinese non-smoking population. RESULTS: Logistic regression analyses revealed that subjects carrying the T allele of IL-1A - 889C/T and IL-1B + 3954C/T had a significant 2.27-2.47-fold (CT, OR [95% CI] = 2.27 [1.12-4.58], p = 0.021; TT, OR [95% CI] = 2.47 [1.32-4.69], p = 0.006) and 1.9-1.99-fold (CT, OR [95% CI] = 1.99 [1-3.93], p = 0.041; TT, OR [95% CI] = 1.9 [1.08-3.43], p = 0.03) increased risk of peri-implantitis, respectively, when using the CC genotype as a reference point. And subjects carrying the TT genotype of IL-1A - 889C/T or IL-1B + 3954C/T also had significantly higher periodontal variables including peri-implant pocket depth (PPD), bleeding on probing (BOP), gingival index (GI), plaque index (PI), calculus index (CI), and clinical attachment level (CAL) (p < 0.05). However, no associations were found between the TNF-α - 308G/A polymorphism and the risk of peri-implantitis. CONCLUSIONS: Our results suggest that the IL-1A - 889C/T or IL-1B + 3954C/T genetic polymorphisms were associated with the risk of peri-implantitis and periodontal status. CLINICAL RELEVANCE: Genetic polymorphisms are constant and can be measured before disease onset, thus it could be of great benefit for treatment planning and prognosis in an early stage.

An objective system for appraising clear aligner treatment difficulty: clear aligner treatment complexity assessment tool (CAT-CAT).

BACKGROUND: Recent years have witnessed a remarkable evolution of clear aligner technology and clear aligners are becoming more and more versatile in treating orthodontic patients. The aim of this study was to develop an objective evaluation system for assessing clear aligner treatment difficulty. METHODS: A total of 120 eligible patients (100 patients for developing and testing the evaluation system and 20 patients for validating this system) were recruited in this retrospective cross-sectional study. Based on clinical data (dental models, radiographs and photographs), complexity levels of cases were evaluated by two experts and regarded as the gold standard. Difficulty scores were determined through an evaluation system encompassing three domains (dental model analysis, radiographic examinations and clinical examinations). The reliability of the evaluation system was examined through analyzing the agreement between complexity levels and difficulty scores. Moreover, multivariable linear regression test was used to examine the independent association of each variable (e.g. overbite and crowding) with the complexity level. RESULTS: The results revealed that the assessment of treatment difficulty by this objective evaluation system substantially matched the gold standard (R2 = 0.80). The multivariable regression test revealed that complexity level was significantly associated with difficulty score (p < 0.001), age (p = 0.015), tooth extraction (p < 0.001), treatment stage (p < 0.01) and the number of difficult tooth movement (p = 0.005). This objective evaluation system elaborated in this study was viable and reliable in appraising clear-aligner treatment difficulty in clinical practice. CONCLUSIONS: We suggest orthodontists and general practitioners use this objective evaluation system (CAT-CAT) to appraise clear aligner treatment difficulty and to select appropriate clear aligner patients.

Subcellular stoichiogenomics reveal cell evolution and electrostatic interaction mechanisms in cytoskeleton.

BACKGROUND: Eukaryotic cells contain a huge variety of internally specialized subcellular compartments. Stoichiogenomics aims to reveal patterns of elements usage in biological macromolecules. However, the stoichiogenomic characteristics and how they adapt to various subcellular microenvironments are still unknown. RESULTS: Here we first updated the definition of stoichiogenomics. Then we applied it to subcellular research, and detected distinctive nitrogen content of nuclear and hydrogen, sulfur content of extracellular proteomes. Specially, we found that acidic amino acids (AAs) content of cytoskeletal proteins is the highest. The increased charged AAs are mainly caused by the eukaryotic originated cytoskeletal proteins. Functional subdivision of the cytoskeleton showed that activation, binding/association, and complexes are the three largest functional categories. Electrostatic interaction analysis showed an increased electrostatic interaction between both primary sequences and PPI interfaces of 3D structures, in the cytoskeleton. CONCLUSIONS: This study creates a blueprint of subcellular stoichiogenomic characteristics, and explains that charged AAs of the cytoskeleton increased greatly in evolution, which offer material basis for the eukaryotic cytoskeletal proteins to act in two ways of electrostatic interactions, and further perform their activation, binding/association and complex formation.

Initial arch wires used in orthodontic treatment with fixed appliances.

BACKGROUND: Initial arch wires are the first arch wires to be inserted into the fixed appliance at the beginning of orthodontic treatment and are used mainly for the alignment of teeth by correcting crowding and rotations. With a number of different types of orthodontic arch wires available for initial tooth alignment, it is important to understand which wire is most efficient, as well as which wires cause least amount of root resorption and pain during the initial aligning stage of treatment. This is an update of the review entitledInitial arch wires for alignment of crooked teeth with fixed orthodontic braces, which was first published in 2010. OBJECTIVES: To assess the effects of initial arch wires for the alignment of teeth with fixed orthodontic braces, in terms of the rate of tooth alignment, amount of root resorption accompanying tooth movement, and intensity of pain experienced by patients during the initial alignment stage of treatment. SEARCH METHODS: Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 5 October 2017), the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library, 2017, Issue 9), MEDLINE Ovid (1946 to 5 October 2017), and Embase Ovid (1980 to 5 October 2017. The US National Institutes of Health Trials Registry (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases. SELECTION CRITERIA: We included randomised controlled trials (RCTs) of initial arch wires to align teeth with fixed orthodontic braces. We included only studies involving participants with upper or lower, or both, full arch fixed orthodontic appliances. DATA COLLECTION AND ANALYSIS: Two review authors were responsible for study selection, 'Risk of bias' assessment and data extraction. We resolved disagreements by discussion between the review authors. We contacted corresponding authors of included studies to obtain missing information. We assessed the quality of the evidence for each comparison and outcome as high, moderate, low or very low, according to GRADE criteria. MAIN RESULTS: For this update, we found three new RCTs (228 participants), bringing the total to 12 RCTs with 799 participants. We judged three studies to be at high risk of bias, and three to be at low risk of bias; six were unclear. None of the studies reported the adverse outcome of root resorption. The review assessed six comparisons.1. Multistrand stainless steel versus superelastic nickel-titanium (NiTi) arch wires. There were five studies in this group and it was appropriate to undertake a meta-analysis of two of them. There is insufficient evidence from these studies to determine whether there is a difference in rate of alignment between multistrand stainless steel and superelastic NiTi arch wires (mean difference (MD) -7.5 mm per month, 95% confidence interval (CI) -26.27 to 11.27; 1 study, 48 participants; low-quality evidence). The findings for pain at day 1 as measured on a 100 mm visual analogue scale suggested that there was no meaningful difference between the interventions (MD -2.68 mm, 95% CI -6.75 to 1.38; 2 studies, 127 participants; moderate-quality evidence).2. Multistrand stainless steel versus thermoelastic NiTi arch wires. There were two studies in this group, but it was not appropriate to undertake a meta-analysis of the data. There is insufficient evidence from the studies to determine whether there is a difference in rate of alignment between multistrand stainless steel and thermoelastic NiTi arch wires (low-quality evidence). Pain was not measured.3. Conventional NiTi versus superelastic NiTi arch wires. There were three studies in this group, but it was not appropriate to undertake a meta-analysis of the data. There is insufficient evidence from these studies to determine whether there is any difference between conventional and superelastic NiTi arch wires with regard to either alignment or pain (low- to very low-quality evidence).4. Conventional NiTi versus thermoelastic NiTi arch wires. There were two studies in this group, but it was not appropriate to undertake a meta-analysis of the data. There is insufficient evidence from these studies to determine whether there is a difference in alignment between conventional and thermoelastic NiTi arch wires (low-quality evidence). Pain was not measured.5. Single-strand superelastic NiTi versus coaxial superelastic NiTi arch wires. There was only one study (24 participants) in this group. There is moderate-quality evidence that coaxial superelastic NiTi can produce greater tooth movement over 12 weeks (MD -6.76 mm, 95% CI -7.98 to -5.55). Pain was not measured.6. Superelastic NiTi versus thermoelastic NiTi arch wires. There were three studies in this group, but it was not appropriate to undertake a meta-analysis of the data. There is insufficient evidence from these studies to determine whether there is a difference in alignment or pain between superelastic and thermoelastic NiTi arch wires (low-quality evidence). AUTHORS' CONCLUSIONS: Moderate-quality evidence shows that arch wires of coaxial superelastic nickel-titanium (NiTi) can produce greater tooth movement over 12 weeks than arch wires made of single-strand superelastic NiTi. Moderate-quality evidence also suggests there may be no difference in pain at day 1 between multistrand stainless steel arch wires and superelastic NiTi arch wires. Other than these findings, there is insufficient evidence to determine whether any particular arch wire material is superior to any other in terms of alignment rate, time to alignment, pain and root resorption.

Evaluation of three-dimensional superimposition technique on parietal bone of the puberty beagle dogs.

OBJECTIVES: This study aimed to (a) evaluate the stability of the parietal bone of 6-9 months old beagles and (b) examine whether parietal regional superimposition can provide an atraumatic and effective solution for further maxillary expansion study. MATERIALS AND METHODS: Six prepubertal 6-month-old male beagles were included. Six miniscrew markers were inserted into the left and right sides of the parietal bone, and two of them were placed bilaterally near the palatal suture. The subjects were scanned with cone beam computed tomography (CBCT) at three time points of T0 (6 months old), T1 (7.5 months old) and T2 (9 months old), respectively. All skull models were analyzed by both the miniscrew superimposition and the parietal regional superimposition. RESULTS: The two superimposition methods had no significant difference (p > 0.05) in displacements of miniscrew markers between left and right first premolars (PM1). The maxillary superimposition between T0 and T2 indicated that the length and width of the maxillary as well as the width of the zygoma root increased significantly (p < 0.05), while the height of maxillary had no significant difference (p > 0.05) over the 3 months. CONCLUSIONS: The parietal bone is relatively stable for beagles from 6 months old to 9 months old and thus can be used as a reference region for 3D skull model superimposition of the beagle dog.

Effect of static magnetic field on pain level and expression of P2X3 receptors in the trigeminal ganglion in mice following experimental tooth movement.

Recent research has demonstrated that static magnetic fields (SMF) can generate an analgesic effect in different conditions. The present study explored effects of SMF on pain levels and expressions of P2X3 receptors in trigeminal ganglion (TG) in mice after experimental tooth movement (tooth movement induced by springs between teeth). Experiments were performed in male mice (body mass: 25-30 g) and divided into SMF + force group, force group, and no force group. Exposure time was over 22 h per day. Mouse Grimace Scale was used for evaluating orofacial pain levels during experimental tooth movement at 4 h and 1, 3, 7, and 14 days. Meanwhile, expression levels of P2X3 receptors in the TG were evaluated by immunohistochemistry and western blotting at same time points. We finally found that during experimental tooth movement, pain levels of mice peaked at 3 days, and then decreased. While pain levels of mice were reduced in the SMF environment at 4 h, 1 and 3 days, there was a significant difference at 1 and 3 days. Meanwhile, under the action of SMF, expression levels of P2X3 receptors in TG were significantly lower at 4 h, 3 and 7 days. These results suggest that SMF can reduce pain levels in mice, and down-regulate P2X3 receptors in TG. Bioelectromagnetics. 38:22-30, 2017. © 2016 Wiley Periodicals, Inc.

Comparison of survival time and comfort between 2 clear overlay retainers with different thicknesses: A pilot randomized controlled trial.

INTRODUCTION: The objective of this 2-arm parallel trial was to compare the survival times, failure rates, and comfort of 2 clear overlay retainers with different thicknesses (0.75 and 1.00 mm). METHODS: Eighty eligible participants who had undergone orthodontic treatment at West China Stomatology Hospital of Sichuan University were recruited and randomly assigned to either the 0.75-mm group or the 1.00-mm group. Eligibility criteria included patients with central incisors, canines, and first molars and no systemic or oral disease. The main outcomes were survival time and total failure rate; the secondary outcomes were rates of different types of failure (fracture, loss, nonfitting, and abrasion); tertiary outcomes included patients' comfort levels assessed with a visual analog scale and a health survey. Randomization was accomplished by tossing a coin, with the allocations concealed in sequentially numbered, opaque, sealed envelopes, and blinding implemented among practitioners, patients, and analysts. Patients were evaluated at 1, 3, 6, and 12 months of follow-up. RESULTS: A total of 80 patients were initially recruited and randomized (42 in the 0.75-mm group, 38 in the 1.00-mm group); 72 patients completed the study and were analyzed (37 in the 0.75-mm group, 35 in the 1.00-mm group); there were 8 dropouts. Baseline characteristics were similar between the groups. At the end of the 1-year follow-up, survival time did not differ significantly between the groups (46.5 days; 95% confidence interval [CI], -10.3 -103.2; P = 0.111). The hazard ratio was 0.77 (95% CI, 0.48-1.24; P = 0.281). With regard to total failure rate, no statistical difference (P = 0.118) existed between the 0.75-mm group (43.2%) and the 1.00-mm group (25.7%) (risk difference, 17.5%; 95% CI, -4.0%-39.1%). Among the different failure types, we found that fracture rates were significantly higher in the 0.75-mm group than in the 1.00-mm group (P = 0.028), whereas other failure types were similar between the groups (all, P >0.05). No clinically significant differences were found in comfort between the 2 groups. No harms were encountered. CONCLUSIONS: Although the 0.75-mm group had a higher fracture rate, our results indicated no evidence that survival and comfort of retainers differ between 1.00 mm and 0.75 mm. When determining the type of retainer to be used, other factors such as retention effectiveness also should be considered. REGISTRATION: This trial was registered at www.clinicaltrials.gov (NCT02618330). PROTOCOL: The protocol was not published before trial commencement.

Needle electromyography of the frontalis muscle in patients with amyotrophic lateral sclerosis.

INTRODUCTION: We sought to determine which muscles to choose for better assessment of the craniobulbar region in establishing the diagnosis of amyotrophic lateral sclerosis (ALS). METHODS: We studied the frontalis muscle in 83 controls and compared it with the tongue, sternocleidomastoid (SCM), and trapezius muscles in 105 definite or probable ALS patients (54 bulbar, 51 nonbulbar). RESULTS: More patients achieved complete relaxation of the frontalis muscle than the tongue or SCM. Motor unit potentials were of longer duration and higher amplitude in ALS patients than in controls (P < 0.05). The frontalis had the same frequency of spontaneous potentials as the tongue, SCM, and trapezius muscles in bulbar ALS patients, but fewer than in the trapezius in nonbulbar patients. CONCLUSIONS: Examining the frontalis provides useful information in establishing the diagnosis of ALS by identifying clinically evident or subclinical abnormalities in the craniobulbar region. Muscle Nerve 54: 1093-1096, 2016.