The developments in materials science and engineering, especially in the field of composites and polymers, have extended the scope of application of such materials in modern industrial construction. ...This article presents polyamide/ aluminium helping hand brackets, designed for use in rainscreens (a.k.a. ventilated façades ) and metal and glass systems. The main purpose of this study was to assess the loadbearing capacity, safety and durability of these elements through laboratory tests and numerical analyses. The laboratory tests were carried out on a three-dimensional test stand. Boundary conditions and the applied loading represented real conditions on the façade (e.g. a typical wind pressure load acting on the façade was used). Next, the experimental results were used to build a representative numerical model. Finite Element analysis was utilised to obtain a true representation of the actual behaviour of the analysed brackets subjected to various loads, taking into account the aluminium/ polyamide interaction. Constitutive behaviour of both materials, polyamide and aluminium alloy, was represented by a linear elastic model. The proposed modelling methodology was validated through full-scale load tests up to failure. The numerical model can be further used to predict the stress and strain fields in newly designed brackets subjected to any type of loading.
Orthodontic Bracket Adjustable In Different Angles Alshahrani, Ibrahim; Alhaizaey, Ali
Annals of Abbasi Shaheed Hospital and Karachi Medical & Dental College,
02/2024, Volume:
29, Issue:
1
Journal Article
Peer reviewed
Open access
Modern advancements in dentistry, like as laser technology and digital dentistry, are increasing the comfort and effectiveness of dental procedures. Dental lasers, for instance, can now be utilized ...more precisely and less invasively for treatments like gum contouring and cavity elimination. The orthodon- tic brackets with adjustable angles, presenting a paradigm shift in orthodontic treatment. These brackets offer unprecedented versatility, enabling orthodontists to customize treatment for diverse cases with unique tooth anatomy and complex malocclusions. The adjustable feature enhances pre- cision and efficiency in tooth movement, potentially reducing treatment time. While promoting im- proved patient comfort through a tailored approach, the technology demands specialized training for effective utilization. The advantages include enhanced versatility, precision, and potential for more efficient outcomes. However, considerations of complexity, maintenance, and associated costs under- score the need for careful assessment and training in incorporating these innovative brackets into orthodontic practice. Overall, adjustable angle brackets signify a promising advancement, balancing customization with practical considerations for optimal orthodontic care
Abstract
The formula ⋆ mod
ō
(
ħ
k
) of Kontsevich’s star-product with harmonic propagators was known in full at
ħ
k
⩾6
since 2018 for generic Poisson brackets, and since 2022 also at
k
= 7 for ...affine brackets. We discover that the mechanism of associativity for the star-product up to
ō
(
ħ
6
) is different from the mechanism at order 7 for both the full star-product and the affine star-product. Namely, at lower orders the needed consequences of the Jacobi identity are immediately obtained from the associator mod
ō
(
ħ
6
), whereas at order
ħ
7
and higher, some of the necessary differential consequences are reached from the Kontsevich graphs in the associator in strictly more than one step.
Aligners are an alternative that are currently being widely used in orthodontic treatment, however, post-treatment relapse following aligner versus conventional treatment has not been compared. The ...objective of this study was to compare post-treatment relapse of orthodontic treatment with dental aligners versus conventional fixed orthodontics through a systematic review.BackgroundAligners are an alternative that are currently being widely used in orthodontic treatment, however, post-treatment relapse following aligner versus conventional treatment has not been compared. The objective of this study was to compare post-treatment relapse of orthodontic treatment with dental aligners versus conventional fixed orthodontics through a systematic review.An exhaustive search was carried out in the MEDLINE (via PubMed), EBSCO, SCOPUS and EMBASE databases up to September 30, 2023. A total of 522 articles were found and after applying the selection criteria, the full texts of 24 articles were chosen for evaluation. At the end of the evaluation, only 3 studies were considered, two observational studies and one randomized clinical trial. The Newcastle Ottawa and Risk of bias (ROB-2) tools were used to assess the risk of bias.Material and MethodsAn exhaustive search was carried out in the MEDLINE (via PubMed), EBSCO, SCOPUS and EMBASE databases up to September 30, 2023. A total of 522 articles were found and after applying the selection criteria, the full texts of 24 articles were chosen for evaluation. At the end of the evaluation, only 3 studies were considered, two observational studies and one randomized clinical trial. The Newcastle Ottawa and Risk of bias (ROB-2) tools were used to assess the risk of bias.Of the three studies, only one (evaluated three years post-orthodontic treatment) identified significant differences in the frequency of relapse following total, maxillary and mandibular anterior alignment using conventional orthodontics. The other two studies (one evaluated at six months and the other two years post-orthodontic treatment) did not show statistically significant differences (p>0.05). In addition, the two latter studies reported slight relapse related to detachment of the fixed retainer.ResultsOf the three studies, only one (evaluated three years post-orthodontic treatment) identified significant differences in the frequency of relapse following total, maxillary and mandibular anterior alignment using conventional orthodontics. The other two studies (one evaluated at six months and the other two years post-orthodontic treatment) did not show statistically significant differences (p>0.05). In addition, the two latter studies reported slight relapse related to detachment of the fixed retainer.The current evidence available indicates a lack of well-designed studies comparing post-treatment orthodontic relapse following the use of dental aligners versus conventional fixed orthodontic treatment, and the studies published to date have a high or moderate risk of bias. However, there are apparently no significant differences in frequency of relapse between the two types of treatment, suggesting similar stability results. Nonetheless, more well-designed studies are required to confirm this observation. Key words:Aligners, brackets, relapse, orthodontic.ConclusionsThe current evidence available indicates a lack of well-designed studies comparing post-treatment orthodontic relapse following the use of dental aligners versus conventional fixed orthodontic treatment, and the studies published to date have a high or moderate risk of bias. However, there are apparently no significant differences in frequency of relapse between the two types of treatment, suggesting similar stability results. Nonetheless, more well-designed studies are required to confirm this observation. Key words:Aligners, brackets, relapse, orthodontic.
Los brackets de autoligado son aquellos que incorporan un mecanismo de cierre que mantiene el arco en el interior de la ranura del bracket. Fueron creados principalmente para crear un sistema de ...menor fricción, permitiendo una mecánica de deslizamiento más eficiente y disminuir el tiempo de tratamiento. Objetivo: El objetivo de esta revisión es presentar de manera más estructurada y ordenada toda la información disponible respecto de los distintos aparatos de autoligado, ya sea activo o pasivo, comparando las cualidades entre sí y con los aparatos convencionales. Método: Se realizó una búsqueda mediante PubMed y Epistemonikos, sin importar idioma o año de publicación. Resultados: Se establecieron comparaciones tanto de brackets de autoligado activos con pasivos, como de brackets de autoligado con brackets convencionales en distintas situaciones clínicas. Conclusiones: Para la gran mayoría de situaciones clínicas, no existe una diferencia estadísticamente significativa, a excepción de la expresión de torque, en donde los brackets convencionales tienen una mayor ventaja.
To investigate whether adhesive precoated brackets (APC) are more efficient than operator-coated brackets (OPC) regarding failure rate, bonding time, patient experience, gingival health, plaque ...accumulation, and white spot lesion formation.
Five online databases: Cochrane Central Register of Controlled Trials (CENTRAL), Scopus, PubMed, MEDLINE, and Web of Science were searched for potential eligible randomized controlled trials (RCTs). A Google Scholar and gray literature search was undertaken. References of included studies were screened for potential eligible studies. Results were collated from each database and modified Cochrane data extraction forms were completed. Quality assessment was performed using Cochrane RoB 2.0 tool for RCTs.
Five studies met the inclusion criteria. All reported failure rates using metal brackets for both APC and OPC systems except one that compared clear APC to clear OPC. Three studies reported bonding time differences between the bracket systems. A quantitative synthesis of four studies reporting failure and three reporting bonding time was undertaken. Random effect meta-analysis determined there were no statistically significant differences in bond failures between bracket systems with an odds ratio of 0.890 (
= .808). Bonding time showed a statistically significant (
= .01) but not clinically significant shorter bonding time with OPC. There was insufficient evidence to assess plaque accumulation, gingival health, and either patient or operator experience.
There is no superiority of either bracket system regarding failure rate. OPC are statistically significantly superior over APC in bonding time although this is most likely not clinically significant.
Orthodontic treatment with fixed vestibular appliances is still widely used worldwide. When choosing the aesthetic alternative of ceramic brackets, the possibility of failure and cracking of braces ...should be considered. Therefore, the aim of the present study was to compare the failure rates of ceramic and metal brackets in a 12-month clinical study.
Eighty patients undergoing fixed orthodontic treatment with vestibular appliances were enrolled and divided into 2 equal groups: MET for metal brackets and CER for ceramic brackets. After bonding, bracket failures were recorded for 12 months, along with the archwire placed at the time of failure. Angle's dental class, skeletal class, Wits appraisal, Little's irregularity index, overjet, overbite, age, and gender of the patients were recorded from pretreatment cephalometric tracings and study casts. The data were statistically analysed (P < .05).
Significantly higher failure rates were found for ceramic brackets in the overall analysis, in the mandibular arch, and in the posterior region. Regression analysis revealed a significant influence of round nickel-titanium archwires on higher failure rates, whilst a significant influence of rectangular archwires was found on lower failure rates.
Ceramic brackets showed higher failure rates. Patients should be aware that orthodontic treatment with ceramic brackets may involve delays and inconvenience due to the higher failure rate compared to metal brackets.
The aim of this study was to quantitatively assess the residual adhesive on orthodontic ceramic bracket-removed dental surface. In orthodontic process, ceramic bracket was repeated debonding ...physically, then the adhesive remained on the dental surface. The residual adhesive caused a lack of adhesive strength between dental and ceramic bracket. Since commonly used adhesive in orthodontics is translucent, residual adhesive is hard to be detected with conventional microscopes. Therefore, 1310 nm center wavelength swept-source OCT system based on laboratory customized image processing algorithm was used for the precise detection of residual adhesive on tooth surface. The algorithm separates residual adhesive from dental surface by comparing the height of adjacent B-scan images, while providing color-scaled images emphasizing the thickness information of residual adhesive. Finally, the acquired results were compared with microscopic and adhesive remnant index scoring gold standards, while the comparison confirmed the potential merits and the improvements of the proposed method over gold standards.
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