Endoscopic submucosal dissection (ESD) of fibrotic colorectal lesions is difficult and has a high complication rate. There are only a few reports on the utility of orthodontic rubber band (ORB) traction in reducing the difficulty of this procedure. This study aimed to investigate the risk factors for perforation when applying ORB traction during ESD of fibrotic colorectal lesions. We continuously collected the clinical data of 119 patients with fibrotic colorectal lesions who underwent ESD with ORB and clip traction between January 2019 and January 2024. Possible risk factors for perforation were analyzed. The median ORB-ESD operative time was 40 (IQR 28-62) min, and the en bloc and R0 resection rates were 94.1% and 84.0%, respectively. Perforation occurred in 16 of 119 patients (13.4%). The lesion size, lesion at the right half of the colon or across an intestinal plica, the degree of fibrosis, operation time, and the surgeon\'s experience were associated with perforation during ORB-ESD (P < 0.05). Multivariate logistic regression analysis showed that lesions in the right colon (OR 9.027; 95% CI 1.807-45.098; P = 0.007) and those across an intestinal plica (OR 7.771; 95% CI 1.298-46.536; P = 0.025) were independent risk factors for perforation during ORB-ESD. ORB-ESD is an effective and feasible approach to treat fibrotic colorectal lesions. Adequate preoperative evaluation is required for lesions in the right colon and across intestinal plicas to mitigate the risk of perforation.

This study aimed to synthesize a novel elastomeric ligature with dimethylaminohexadecyl methacrylate (DMAHDM) grafted, providing a new strategy for improving the issue of enamel demineralization during fixed orthodontics. DMAHDM was incorporated into elastomeric ligatures at different mass fractions using ultraviolet photochemical grafting. The antibacterial properties were evaluated and the optimal DMAHDM amount was determined based on cytotoxicity assays. Moreover, tests were conducted to evaluate the in vivo changes in the mechanical properties of the elastomeric ligatures. To assess the actual in vivo effectiveness in preventing enamel demineralization, a rat demineralization model was established, with analyses focusing on changes in surface microstructure, elemental composition, and nanomechanical properties. Elastomeric ligatures with 2% DMAHDM showed excellent biocompatibility and the best antibacterial properties, reducing lactic acid production by 65.3% and biofilm bacteria by 50.0% within 24 h, without significant mechanical property differences from the control group (p > 0.05). Most importantly, they effectively prevented enamel demineralization in vivo, enhancing elastic modulus by 73.2% and hardness by 204.8%. Elastomeric ligatures incorporating DMAHDM have shown great potential for application in preventing enamel demineralization, providing a new strategy to solve this issue during fixed orthodontics.

The potential of using specimens with a double-semicircular-notched configuration for performing tensile tests of orthodontic thermoplastic aligner materials was explored. Unnotched and double-semicircular-notched specimens were loaded in tension using a universal testing machine to determine their tensile strength, while finite element analysis (FEA) and digital image correlation (DIC) were used to estimate stress and strain, respectively. The shape did affect the tensile strength, demonstrating the importance of unifying the form of the specimen. During the elastic phase under tension, double-semicircular-notched specimens showed similar behavior to unnotched specimens. However, great variance was observed in the strain patterns of the unnotched specimens, which exhibited greater chance of end-failure, while the strain patterns of the double-semicircular-notched specimens showed uniformity. Considerable agreement between the theoretical (FEA) and practical models (DIC) further confirmed the validity of the double-semicircular-notched models.

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OBJECTIVE: The study endeavors to undertake a bibliometric analysis on molar distalization, with the objective of illuminating its evolutionary trajectory, current status, and prognosticating future research hotspots and trends.
METHODS: A comprehensive exploration of the literature on molar distalization was carried out by conducting a search in the Web of Science (WOS) core database of the University of Hong Kong Electronic Library. The search for topic terms employed included \"molar distalization,\" \"molar distalisation,\" \"move molar distally,\" \"molar distal movement,\" and \"molar backwards.\" The search results were subsequently subjected to meticulous analysis using CiteSpace software. This analysis encompassed various facets such as the citation count; the geographical distribution of the countries, institutions, and journals responsible for publishing the articles; the distribution of the authors; the utilization of keywords within the articles; and the analysis of references.
RESULTS: A total of 516 articles were included in the analysis. The top 5 countries in terms of the number of published papers were the United States (USA), South Korea, Turkey, Italy, and Germany, and the top 5 institutions in terms of the number of published papers were Kyung Hee University, A.T. Still University of Health Sciences, Catholic University of Korea, Seoul St. Mary\'s Hospital, and Universidade de Sao Paulo. The top 5 authors in terms of the number of published papers were Park, Kook, Bayome, Janson, and Lee. There was little cooperation overall. The top 3 journals in terms of the most published related articles were all orthodontic-related journals. After molar distalization and anchorage, the most frequently used keywords were distalization, movement, and pendulum appliance. Kinzinger GSM is the most frequently cited author in references, and one of his articles also has the highest centrality score in references.
CONCLUSIONS: As the tides of time shift and scholars display an ever-growing dedication to unraveling the intricacies of this therapeutic modality, the realm of molar distalization has undergone notable advancements in technology. Initially, the traditional appliance suffered from aesthetic drawbacks and discomfort. However, contemporary iterations of the appliance have transcended these limitations, boasting enhanced elegance and convenience while concurrently elevating their efficacy. Nevertheless, limitations of current appliances, including their durability and propensity for recurrence post-treatment, continue to necessitate further advancement. Hence, the ongoing scientific inquiry aims to delve deeper into refining treatment modalities and fabricating cutting-edge appliances within this realm.
CONCLUSIONS: This study holds the potential to significantly enhance the ability of orthodontists to devise treatment protocols and offer state-of-the-art clinical recommendations, thereby empowering them to deliver advanced and refined orthodontic interventions.

BACKGROUND: Clear aligners (CAs) have recently become popular and widely used orthodontic appliances. Research on CA biomechanics has become a focal point in orthodontics to improve the efficiency of CA treatment and address challenging issues, such as extraction. The biomechanical characteristics of CAs in space closure have been reported. However, previous studies have mainly focused on static biomechanical analysis that cannot demonstrate the dynamic biomechanical changes in CAs during space-closing. Given that these biomechanical changes can be significant and have considerable clinical value, this study aimed to investigate these characteristics.
METHODS: Sequential extraction space-closing models were derived from included patient data and refined using modeling and CA design software. A finite element analysis was performed to obtain biomechanical raw data. This study introduced a dual coordinate system and space geometry analysis to demonstrate the biomechanical properties accurately.
RESULTS: As space closure progressed, the instantaneous tooth displacements increased, indicating an enhanced space closure force because of the increased strain in the CA extraction area. Meanwhile, the central axis of rotation of the anterior teeth continuously moved toward the labial-apical direction, showing a gradually enhanced vertical and torque control effect.
CONCLUSIONS: During space closure, CAs undergo specific biomechanical changes, including increased contraction and control forces on both sides of the gap. These biomechanical effects are beneficial to alleviate the roller coaster effect gradually. Meanwhile, more reasonable staging design strategies can be proposed on the basis of this biomechanical mechanism.

To compare force degradation of elastomeric chains and NiTi coil springs in vivo and in vitro, and evaluate the effects of pre-stretched and reused elastomeric chains in the oral cavity during the time.
In the in vitro groups, 4-unit elastomeric chains and NiTi coil springs with an initial force of 200 g were placed in dry air and artificial saliva. The volunteers wore clear retainers which were used to hold the sample of 4-unit chains, pre-stretched 4-unit chains, and NiTi coil springs with the initial force of 200 g in the in vivo groups. After the first 4 weeks, 4-unit specimens were stretched to 200 g again for another 4 weeks in vivo. The force value and the percentage of force degradation were recorded at each measurement time interval in the in vivo and in vitro groups.
The force degradation of elastomeric chains was greatest within the initial 4 hours, followed by a more stable phase after 1 week. The average force degradation of 4-unit elastomeric chains after 4 weeks was in vivo (64.8%) > artificial saliva (55.0%) > dry air (46.42%) (P < 0.05). The force degradation of NiTi coil springs in vivo (15.36%) or in artificial saliva (15.8%) was greater than in dry air (7.6%) (P < 0.05). NiTi coil springs presented a gentler force decay than elastomeric chains during the period (P < 0.05). In vivo, the force degradation of pre-stretched and reused elastomeric chains decreased less than the regular style(P < 0.05).
The force degradation of the elastomeric chains and NiTi coil springs varied in different environments. NiTi coil springs presented a gentler force decay than elastomeric chains during the period. Orthodontists should consider the force degradation characteristics of orthodontic accessories in clinical practice.

This study aimed to compare the pain intensity and impacts on oral health-related quality of life (OHRQoL) between orthodontic patients treated with clear aligners (CAs) and fixed appliances (FAs).
A systematic search was conducted up to December 2022 using PubMed, Web of Science, Cochrane Central Register of Controlled Trials, and Embase. Randomized controlled trials (RCTs) and prospective non-randomized controlled trials (non-RCTs) comparing pain intensity or OHRQoL between patients treated with CAs and FAs were included. The risk of bias (RoB) of individual studies was evaluated using the Cochrane RoB tool 2.0 and ROBINS-I tool for RCTs and non-RCTs, respectively. Further, meta-analyses were separately conducted for each included study using the total oral health impact profile (OHIP)-14 and visual analog scale (VAS) scores to evaluate OHRQoL and pain intensity, respectively.
Overall, 12 studies (5 RCTs and 7 non-RCTs) were included in the study. Subgroup analyses conducted according to the total OHIP-14 scores revealed that patients treated with CAs had higher OHRQoL at 1 week, 1 month, and 6 months of the treatment. Meanwhile, subgroup analyses conducted according to the VAS scores revealed that pain levels were lower in the CA group only at 3 and 4 days of the treatment.
Patients treated with clear aligners had higher OHRQoL than those treated with fixed appliances during orthodontic treatment. However, OHRQoL appeared to be similar between the two groups at the end of the treatment. Moreover, patients treated with clear aligners experienced lesser pain than those treated with fixed appliances on the third and fourth day after the initial treatment. The difference in pain intensity between the two treatment modalities was not noted at other time points.

OBJECTIVE: To investigate the salivary bacterial communities during the first 6-month orthodontic treatment with Clear Aligners (CA) and Fixed Appliances (FA), and its correlation with clinical periodontal parameters.
METHODS: Saliva and periodontal parameters were sampled from individuals wearing CA or FA before treatment (T0), and after 3- (T3) and 6-month (T6) treatments. Salivary bacterial communities characterized based on the 16S rRNA V3-V4 region were compared between FA and CA and correlated with clinical periodontal parameters.
RESULTS: Probing Depth (PD) significantly increased at T6 in the FA group versus T0, whereas it remained stable in the CA group. The Shannon and Pielou indices were significantly higher in the FA group and significantly positively correlated with periodontal inflammation parameters. β-diversity analysis revealed distinct communities between the FA group and CA group at T6. The relative abundances of 3 genera and 15 species were significantly higher in the FA group. Among the above appliance-type related taxa, bacterial genera Selenomonas, Stomatobaculum, Olsenella and Faecalicoccus and bacterial species Selenomonas_sputigena, Dialister_invisus, Olsenella_profus, Prevotella_buccae, Cryptobacterium_curtum and Clostridium_spiroforme were significantly positively associated with periodontal parameters.
CONCLUSIONS: Orthodontic treatments trigger appliance-related salivary bacterial communities, highlighting the importance of developing appliance-orientated periodontal strategies during orthodontic treatments. Salivary bacterial communities harboured by patients wearing FA possess higher bacterial parameters which were associated with increasing PD, PI and Gingival Index.

The benefits of lingual orthodontics go beyond appearance. In this case study, a 30-year-old female patient was treated with a custom lingual orthodontic appliance for a Class II high-angle malocclusion, anterior open bite, incisor biprotrusion and crossbite, unilateral second molar scissor bite and dysfunctional tongue thrust. To achieve a counterclockwise rotation of the mandible, implant anchorage was used to control the vertical height. To complete the compensatory therapy, four first premolars were removed. As well as ensuring aesthetics over the 20-month treatment period, the treatment also established a Class I molar relationship, normal overbite and overjet, and improved the facial profile. After a five-year follow-up, the treatment results remained stable.