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Introduction: The aim of this study was to investigate the effects of direct attachment shape and location on the forces and moments generated by thermoplastic aligners during simulated maxillary central incisor torque., Materials and Methods: A total of 7 typodonts were digitally printed with different attachment design and locations. Five clear aligners were fabricated for each typodont and placed on an orthodontic force tester (OFT) with the maxillary central incisor rotated palatally 1° around the incisal edge. Forces and moments were measured 2 times by the load cells. Analysis of variance (Anova) was used to determine the effects of group, tooth, and the group-by-tooth interaction on the outcomes; A two-sided 5% significance level was used for all tests. Analyses were performed using SAS version 9.4 (SAS Institute Inc., Cary, NC, USA)., Results: The two-way interactions between group and tooth were significant (P<0.001) for all outcomes except facial/palatal moment around the X axis (M x ) (P>0.05). The horizontal ellipsoid attachment at the middle third generated the highest M x (-25.74±8.93Nmm) with facial crown/palatal root, while the rectangular attachment at the middle third yielded the lowest Mx (3.31±12.92Nmm)., Conclusions: Changing attachment shape and location had a significant effect on the forces and moments generated during simulated maxillary incisor torque. The best design for the incisor torque movement was found to be the horizontal ellipsoid attachment at the middle third. Besides the desired torque moment, all attachment shape and location combinations produced a vertical extrusive force as a side effect., (Copyright © 2025 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Objectives: The aim of this study was to compare the effectiveness of different attachment shapes and locations on the extrusion of the upper left lateral incisor (UL2) using thermoplastic aligners., Materials and Methods: Seven typodonts were digitally printed with hemi-ellipsoid or rectangular attachments in the incisal, middle or cervical third of the UL2. Five clear aligners were fabricated for each typodont; each was tested twice. Forces and moments were measured with an orthodontic force tester during 0.2 mm simulated extrusion of the UL2. Analysis of variance (ANOVA) was used to determine the effects of group, tooth, and the group-by-tooth interaction on the outcomes. A two-sided 5% significance level was used for all tests., Results: Altering attachment shape and location had a statistically significant effect on the forces and moments generated in each trial (p < 0.01), except for rectangular incisal and hemi-ellipsoid cervical (p > 0.05). The rectangular middle attachment generated the highest extrusive force (Fz = 7.498 N), followed by hemi-ellipsoid cervical (Fz = 6.338 N) and rectangular incisal (Fz = 5.948 N)., Conclusions: Varying direct attachment shape and location on the UL2 during extrusion has a significant effect on the forces and moments generated by thermoplastic aligners. The rectangular attachment located in the middle third generated the most effective extrusive force and least unwanted moment. For anchorage teeth, hemi-ellipsoid attachments located in the cervical third were found to be the most effective in minimising the reciprocal intrusive forces and unwanted moments., (© 2024 The Author(s). Orthodontics & Craniofacial Research published by John Wiley & Sons Ltd.)

Objective: To evaluate the effects of varying direct attachment shape and size on the forces and moments generated by thermoplastic aligners during simulated expansion., Materials and Methods: An in vitro orthodontic force tester (OFT) was used to measure the forces and moments from a typodont where the buccal teeth were translated lingually 0.2 mm to simulate expansion. Hemi-ellipsoid and rectangular attachments with either 0.5 or 1.0 mm thickness were added on upper right first premolar (UR4), second premolar (UR5) and first molar (UR6). Analysis of variance (ANOVA) was used to determine two-way interactions among the factors on the outcomes., Results: The interactions between group and tooth were significant for all outcomes (p < 0.001). The greatest buccal forces (Fy) were observed with 1 mm rectangular attachment on the UR4 (0.78 ± 0.29 N), with 1 mm hemi-ellipsoid attachment on UR5 (0.28 ± 0.21 N) and with 0.5 mm rectangular attachment on UR6 (1.71 ± 0.18 N). The greatest buccolingual moments (Mx) were obtained with 1 mm rectangular attachment on UR4 (5.61 ± 1.43 Nmm), without any attachments on UR5 (3.33 ± 1.73 Nmm) and with 1 mm hemi-ellipsoid attachment on UR6 (4.18 ± 4.31)., Conclusion: Direct attachment shape and size had a significant effect on the orthodontic forces and moments generated by thermoplastic aligners during simulated expansion. Although loads varied significantly by tooth morphology and its location in the arch, best forces and moments for expansion were obtained with 1 mm rectangular attachments on UR4s, 1 mm hemi-ellipsoid attachments on UR5s and 0.5 mm rectangular attachments on UR6s., (© 2024 The Author(s). Orthodontics & Craniofacial Research published by John Wiley & Sons Ltd.)

While the durability of thermoplastic aligners has been the subject of numerous studies, the durability of thermoplastic retainers has received significantly less attention. Patients are often advised to wear their thermoplastic retainers indefinitely, so the durability of the materials used in their fabrication is crucial to determining whether they are worth the cost. Limited studies have evaluated the properties of thermoplastic retainer materials and the effects of thermocycling on their mechanical properties. Thus, this study aimed to examine six thermoplastic retainer materials after thermoforming with and without thermocycling. The materials' flexural modulus, hardness, and surface roughness values were measured after thermoforming (Group 1) and after thermoforming with subsequent thermocycling for 10,000 cycles (Group 2). After thermoforming, there was a significant difference in flexural modulus and hardness values between most of the materials. However, their surface roughness was not significantly different (p < 0.05). After thermocycling, the flexural modulus and hardness increased significantly for most tested materials (p < 0.05) compared to Group 1. Concerning the surface roughness, only two materials showed significantly higher values after thermocycling than Group 1. Thus, all the mechanical properties of the evaluated materials differed after thermoforming, except the surface roughness. Moreover, while thermocycling made the materials stiffer and harder in general, it also made some of them rougher. [ABSTRACT FROM AUTHOR]

Contemporary orthodontics entails using advanced materials and devices, simplifying the process of tooth movement. It is well documented that orthodontic materials are subjected to various fluctuations and stresses in the oral environment, such as salivary pH, dietary habits, temperature changes, and masticatory loads. These changes reduce bonding materials’ longevity, plasticize resin polymers, and reduce elastic properties. In addition, the corrosion of orthodontic appliances in the oral environment has concerned clinicians for some time. This is focused on two principal issues: whether corrosion products are absorbed into the body and cause either localized or systemic effects, and the results of corrosion on the physical properties and the clinical performance of orthodontic appliances. Recently, another major concern is the potential release of bisphenol‑A from materials containing polymers such as thermoplastic aligners and resins, which is known to induce xenoestrogenicity and cytotoxicity when the tissue level exceeds the daily recommended intake. However, most of these findings are based on in vitro studies that suffer from serious drawbacks such as failure to replicate the exact oral environment and process during orthodontic treatment. Therefore, developing clinically relevant methods should be the goal of future research related to the aging of orthodontic materials. The purpose of this review is to outline the impact of the oral environment on contemporary orthodontic materials. [ABSTRACT FROM AUTHOR]

BACKGROUND: White spot lesions (WSL) are an unsightly and a rather frequent drawback of orthodontic treatment. The complex design of fixed orthodontic appliances (FAs) makes it difficult to perform proper oral hygiene, which amounts to white spot lesions being three times more prevalent in patients wearing orthodontic appliances. As clear thermoplastic aligners (CAs) are removable appliances, it has been speculated that they allow better oral hygiene maintenance and thus less incidence of WSLs. OBJECTIVES: This evidence-based scoping review aims to identify the scope and nature of the evidence on white spot lesions during orthodontic clear aligner therapy. TYPES OF STUDIES REVIEWED: Strategic and thorough search of the literature for randomized Controlled Trials, Case-Control, Cohort studies, Case reports, full research articles, and review papers on humans published in English in five major databases was undertaken till July 2021 using free text and Medical Subject Headings (MESH) terms, followed by Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) to identify five studies for data extraction. RESULTS: Evidence was summarized for study characteristics, diagnostic methods for the detection of white spot lesions, and incidence of white spot lesions during clear aligner therapy. The literature supports that orthodontic treatment with CAs was associated with a low incidence of WSLs when compared with fixed mechanotherapy, with a major role of patient education, motivation, and compliance in maintaining oral hygiene. PRACTICAL IMPLICATIONS: The general perception is that clear aligners are more hygienic and show no incidence of white spot lesions. However, our scoping review supports that WSLs can occur with this form of orthodontic treatment also. WSLs in clear aligners could be attributed to the practice of having composite attachments that cover a significant portion of the tooth surface. Thus, regardless of the type of appliance used, a periodic reinforcement by the orthodontist to maintain oral hygiene is necessary for patient motivation, allowing for better oral hygiene practice, and as a result, leads to prevention of WSLs. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the accuracy of 3-dimensional (3D) printed aligners compared to conventional vacuum-formed thermoplastic aligners with varying levels of dental crowding. Digital intraoral scans of 10 cases were assigned to their respective groups (n = 10, each, 30 total) as follows: no crowding (control), moderate crowding, and severe crowding. Digital images of these models were created in standard tessellation language (STL) file format using 3Shape software and randomly 3D printed. The STL files of each case were also sent to a dental laboratory to fabricate vacuum-formed samples, the current technology used for manufacturing aligners. The intaglio surfaces of fabricated aligners in both groups were scanned using cone beam computed tomography to create STL files, which were then compared to the original STL files of the cases using Geomagic Control X software. Absolute deviations from the original file and root mean square values were recorded. A Kruskal-Wallis test was conducted to analyze the difference in average deviation, and a t-test was repeated for the RMS measure. The significance level was set at 0.05. The crowding did not affect the trueness of aligners manufactured using 3D printing or conventional vacuum-forming techniques (P = 0.79). 3D-printed aligners showed less deviation than the vacuum-formed samples (0.1125 mm vs 0.1312 mm; P <0.01). Aligners manufactured with the vacuum-forming technique had significantly higher variation than those with the 3D printing process (P = 0.04). 3D aligners printed directly from an STL file exhibited better precision and trueness than those fabricated using the conventional vacuum-forming technique. Since accuracy is defined as a combination of precision and trueness, it is concluded that direct printing from an STL file can be used to manufacture aligners. • 3D printed aligners had more precision and trueness than vacuum-formed aligners. • The amount of crowding did not influence the accuracy of 3D-printed or vacuum-formed aligners. • 3D printed and vacuum-formed aligners are clinically acceptable for all crowding levels. • Direct 3D printing from standard tessellation language files can be used to manufacture aligners. [ABSTRACT FROM AUTHOR]

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(1) Background: The intra-oral behavior of clear thermoplastic dental materials can be influenced by various intrinsic and extrinsic factors. Aim: The purpose of this in vitro study was to evaluate the optical properties, color changes and whiteness variations of four thermoplastic polymers used for dental appliances, in a simulated oral environment. (2) Methods: Customized thermoformed specimens of four PETG thermoplastics were selected and investigated in this study: Leone [L], Duran [D], Erkodur [E] and Crystal [C]. The thermoplastic samples were divided into three groups related to pH values (neutral, acidic and basic). A period of 14 days was simulated. Five stages resulted: I. dessicated specimens; II. hydrated in artificial saliva; III. subsequent desiccated; IV. artificial aged; V. further dessicated. Optical CIE L*a*b* coordinates were determined and optical properties, like TP (translucency), OP (opalescence) values, color differences ΔE-NBS, white indexes in dentistry WID and white index differences ΔWID were calculated for all stages of the study, for each group of the materials. Statistical analyses were performed. (3) Results: Optical properties of PETG clear thermoplastic materials, like TP and OP, increase in a simulated oral environment and the changes become significant after artificial aging. Related to pH values, the optical behavior between the materials is significantly different. During artificial aging, the tested materials behave significantly differently in terms of optical properties. (4) Conclusions: After the simulated period of 14 days, TP and OP values increase, with a migration of the color towards red and yellow. Color changes in some cases even reach the level of extremely marked. Whiteness increases, and the differences are mostly perceptible, but partially exceed the limit of acceptability. [ABSTRACT FROM AUTHOR]

An inaccurate bonding procedure of the attachments related to clear aligner systems could influence the predictability of tooth movement The aim of this study was to compare the positioning reliability of horizontal and vertical orthodontic clear aligner attachments. Materials and Methods: A total of 70 horizontal and 70 vertical orthodontic clear aligner attachments were bonded to five upper and five lower experimental anatomically based acrylic resin models with 14 clinical crowns each. The experimental anatomically based acrylic resin models were randomly distributed to the following study groups: Group A—horizontal orthodontic clear aligner attachments (n = 70) (HORIZONTAL) and Group B—vertical orthodontic clear aligner attachments (n = 70) (VERTICAL). Afterward, the orthodontic clear aligner attachments were digitally planned using orthodontic planning software, and orthodontic templates were manufactured by thermoforming on 3D-printed models in trilayer glycol-modified polyethylene terephthalate. Both horizontal and vertical orthodontic clear aligner attachments were put through an intra-oral scan to obtain a postoperative digital image, and PAPver, PCPver, PMVver, AUver, Alver, PPMhor, PPDhor, PMVhor, AMhor and ADhor cephalometric parameters were analyzed using a t-test or a non-parametric Mann–Whitney–Wilcoxon test. Results: The results showed that all cephalometric parameters showed statistically significant differences (p < 0.05) between the accuracy of the indirect bonding technique for horizontal and vertical orthodontic clear aligner attachments, except for the PAPver (p = 0.6079) and PMVhor (p = 0.5001) cephalometric parameters. Conclusions: The vertical orthodontic clear aligner attachments are more accurate than the horizontal orthodontic clear aligner attachments through the indirect bonding technique. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to compare the effects of orthodontic treatment on the same patients using aligners (upper arch) versus traditional fixed appliances (lower arch) on oral hygiene and periodontal health. Materials and Methods: A total of 90 patients, all treated by the same orthodontist and with an average age of 26 years, were included in the study. The research focused on factors predisposing patients to periodontitis, as well as plaque and tartar accumulation. Statistical analysis was performed using the paired-samples Student's t-test, with values of p < 0.05 deemed statistically significant. Results: Patients treated with fixed orthodontic appliances generally showed increased plaque accumulation (+10% PI) and a decline in periodontal health compared to those treated with aligners (40% presented a high level of S.Mutans and Lactobacilli). In patients who did not maintain proper oral hygiene, the initial conditions of the upper arch remained stable, while the lower arch exhibited significant deterioration, with increased plaque buildup and greater tissue inflammation. Conclusions: The findings emphasize the critical role of individual oral hygiene practices during orthodontic treatment in preserving periodontal health. Aligners appear to be more favorable in protecting periodontal tissues, improving plaque control, and reducing gingival inflammation. Various supplementary approaches for plaque management and microbial colonization in saliva should be implemented based on the type of orthodontic appliance used. [ABSTRACT FROM AUTHOR]

Background: Retention is a critical aspect of orthodontic treatment with aligners as it counteracts vertical displacing forces and ensures greater predictability of tooth movement. The aim of this study is to evaluate and compare the retention effectiveness of 3D-printed aligners and thermoformed aligners, analyzing how margin design and thickness gradients affect retention under different occlusal conditions. Methods: Tensile tests were conducted using a Sauter TVO-A01 machine, recording the force required to displace each aligner from the models. Quantitative data on the retention force of each aligner were collected based on malocclusion type and design specifics. Results: Scalloped thermoformed aligners demonstrated significantly lower retention values (p = 0.029) compared to 3D-printed aligners with high margins with horizontal and vertical gradients. Scalloped margin aligners exhibited significantly lower retention values (p = 0.008) compared to straight margin aligners. Additionally, 3D-printed aligners with uniform thickness gradients had significantly lower retention values (p = 0.040) compared to thermoformed aligners. Conclusions: The 3D printing production process enables customizable designs tailored to the unique characteristics of each patient. High-margin 3d-printed aligners with horizontal and vertical gradients provide superior retention, particularly in complex clinical situations such as dental crowding. [ABSTRACT FROM AUTHOR]

Background: A decrease in oral pH levels may have detrimental effects on vacuum-formed retainers since an acidic oral environment could impact the mechanical and physical properties of these retainers. The present In vitro study aimed to evaluate the effect of simulated gastric acid at pH 4 and 1.2 on the surface microhardness, flexural strength, and color change of three different types of orthodontic retainer materials. Methods: A total of 144 vacuum-formed commercially available retainer materials: copolyesters, polypropylene, and PET-G (n = 48/group) were evaluated. Each specimen was immersed in distilled water, and then the specimens were divided into two subgroups: those with a pH of 4 and those with a pH of 1.2. The microhardness test was performed using Innovatest, the flexural strength was evaluated by a universal testing machine, and the color change was analyzed using a spectrophotometer. The data were analyzed using One-Way ANOVA and independent sample t test at a significance value of P ≤ 0.05. Results: Our findings indicated a significant decrease in flexural strength in all the experimental groups after immersion in pH 1.2 and 4 solutions (P < 0.001), with PET-G being the most affected material, followed by copolyester and polypropylene. Only copolyester demonstrated a significant decrease in surface microhardness following immersion in a pH 4 solution (P = 0.025). All materials exhibited the greatest degree of color alteration CP (P = 0.006), PP (P = 0.001), and PET-G (P = 0.009) respectively. Conclusion: The study concluded that copolyester adversely affects flexural strength, surface microhardness, and color when subjected to immersion in simulated gastric acid. Therefore, care is recommended for patients diagnosed with gastroesophageal reflux disease. [ABSTRACT FROM AUTHOR]

Introduction: This study developed an elastic silicone appliance material incorporating sodium fluoride (NaF) and evaluated its mechanical properties, biocompatibility, antibacterial effects, and remineralization potential. Methods: Silicone components A and B were combined with varying concentrations of NaF (0.5, 1, 1.5, 2, and 2.5%), thoroughly mixed, and transferred into molds. After drying and curing, the resulting orthodontic appliance was retrieved from the mold and underwent finishing processes, followed by the assessment of its mechanical properties, cytotoxicity, and antibacterial impact. Additionally, the impact of this novel silicone appliance material on salivary biofilm's activity and acid production was evaluated in samples from children with severe early childhood caries (S-ECC). The hardness of demineralized and remineralized bovine enamel was measured. Results: Incorporating NaF (0.5, 1, and 1.5%) resulted in no cytotoxic effects, with cell viability >85%. The fluoride release rate initially increased over 14 days, followed by a gradual decline, maintaining a steady release for approximately 28 days. Incorporating 1.5% NaF preserved the mechanical properties and exhibited specific antibacterial properties that inhibited the growth, biofilm formation, and acid production activity of Streptococcus mutans (S. mutans) and saliva biofilms from S-ECC children. Furthermore, all concentrations of the samples helped improve enamel hardness loss. Discussion: The novel silicone appliance material incorporating NaF exhibited antibacterial, fluoride releasing, and enamel remineralization properties while maintaining its physical and chemical integrity without cytotoxic effects. [ABSTRACT FROM AUTHOR]

Objective To evaluate the stain resistance and color stability of four Clear aligners (CA) brands against various beverages at different intervals, along with assessing the elaboration of cleaning agents. Methods In a strictly controlled lab environment, 48 CAs from four different companies (Invisalign, EON, Clear Cap, and K clear) were immersed for seven days in six different beverages based on their pH (Pepsi, orange juice, milk, coffee, and black tea), as well as a control solution (distilled water). The VITA Easy-Shade compact colorimeter used the Commission International lightening L*a*b* color scheme to evaluate the color change of the aligners at four intervals. T0: before immersing in the solution; T1: twelve hours after immersion; T2: seven days after immersion; and T3/T4: fifteen minutes after exposure to two cleaning agents. The color values were then converted into National Bureau of Standards System (NBS) units. The statistical analysis was carried out using SPSS. A one-way ANOVA test was used to compare the mean color change values of all aligners and staining agents. Results A significant color change in aligners was observed after immersion in the stated solutions (p = 0.01). Additionally, there is a difference when washing with Invisalign foam and M3 cleaners (p < 0.001). Similarly, there were significant color variations between twelve hours and seven days after soaking (p = 0.01). Nonetheless, there were no significant differences in discoloration among the CAs’ manufacturing materials. Conclusions CAs’ staining ability at different time intervals after immersion in various solutions was clearly visible. Aligner cleanser use has a substantial influence on reducing acquired pigmentation. However, there were minimal differences in discoloration across CA brands. [ABSTRACT FROM AUTHOR]

Objective: This study aims to analyze the differences in gingivitis incidence among adolescents and adults using clear aligners for orthodontic correction and to evaluate the effectiveness of prevention strategies on orthodontic outcomes. Methods: This observational study included 120 patients undergoing clear aligner orthodontic treatment from June 2018 to September 2023. Participants were divided into an adolescent group (66 cases) and an adult group (54 cases), each further split into a study group and a control group. The control group patients maintained their daily lifestyle throughout the study period. The study group received personalized oral hygiene education and guidance on self-oral care techniques at each follow-up visit. Routine periodontal treatment and personalized oral hygiene education were provided, and the incidence of gingivitis was evaluated six months post-treatment. Statistical methods, including chi-square tests for categorical data, t-tests for continuous variables, and two-way ANOVA for group comparisons, were employed to ensure the robustness of the results. Results: The incidence of gingivitis was significantly higher in the adolescent group compared to the adult group (P < 0.05). Specifically, within the adolescent group, the study group exhibited a higher gingival index (GI) than the control group (P < 0.05), while the difference in the adult group was not significant. Conclusion: During clear aligner orthodontic treatment, adolescents are more prone to developing gingivitis than adults. Additionally, basic periodontal therapy, as opposed to verbal oral health education alone, can moderately reduce the incidence of gingivitis in clear aligner patients during treatment. [ABSTRACT FROM AUTHOR]

Objective: The primary focus of this investigation was to evaluate the biomechanical effects of high trimline design aligners on the distalization of mandibular molars, employing three-dimensional finite element analysis (3D-FEA). The study concentrated on aspects such as tooth movement, stress distribution, and anchorage control. Methods: Utilizing Cone-beam computed tomography (CBCT) data, a detailed 3D geometrical model was constructed for finite element analysis. This model was used to assess four variations of aligner trimlines, alongside the employment of Class III traction. Analyses were conducted to examine stress distributions and tooth displacements in these different scenarios. Results: Aligners with a high trimline design were found to be more effective in facilitating the distal movement of mandibular molars than those with scalloped trimlines, providing improved management over tooth movement and stress distribution. In specific configurations where Class III traction was applied, a reduction in the deformation of anterior teeth was observed, which enhanced anchorage stability. Nevertheless, the anterior teeth in all configurations were subjected to compressive stresses that surpassed thresholds likely to induce external root resorption, underlining the importance of vigilant monitoring. Conclusions: The research verified the biomechanical advantages of high trimline aligners in the distal movement of mandibular molars and underscored the critical role of aligner design and traction application in optimizing orthodontic treatment outcomes. Additionally, it raised concerns regarding the potential for root resorption due to significant stress in the periodontal ligament, necessitating thorough observation of patients, particularly those fitted with high trimline aligners. Despite these insights, the study's findings are derived from the data of a single patient, suggesting a need for further investigations involving broader samples and extended clinical assessments. [ABSTRACT FROM AUTHOR]

Novel low-cost portable spectrophotometers could be an alternative to traditional spectrophotometers and calibrated RGB cameras by offering lower prices and convenient measurements but retaining high colorimetric accuracy. This study evaluated the colorimetric accuracy of low-cost, portable spectrophotometers on the established color calibration target—RAL Design System Plus (RAL+). Four spectrophotometers with a listed price between USD 100–1200 (Nix Spectro 2, Spectro 1 Pro, ColorReader, and Pico) and a smartphone RGB camera were tested on a representative subset of 183 RAL+ colors. Key performance metrics included the devices' ability to match and measure RAL+ colors in the CIELAB color space using the color difference CIEDE2000 ΔE. The results showed that Nix Spectro 2 had the best performance, matching 99% of RAL+ colors with an estimated ΔE of 0.5–1.05. Spectro 1 Pro and ColorReader matched approximately 85% of colors with ΔE values between 1.07 and 1.39, while Pico and the Asus 8 smartphone matched 54–77% of colors, with ΔE of around 1.85. Our findings showed that low-cost, portable spectrophotometers offered excellent colorimetric measurements. They mostly outperformed existing RGB camera-based colorimetric systems, making them valuable tools in science and industry. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the efficacy of microchips and 3D microsensors in the measurement of orthodontic forces. Methods: Through September 2023, comprehensive searches were conducted on PubMed/MEDLINE, SCOPUS and SCIELO without restrictions. Results: After removing duplicate entries and applying the eligibility criteria, 23 studies were included for analysis. All the studies were conducted in vitro, and slightly more than half of them were centred on evaluating orthodontic forces exerted by aligners. Eight utilized microchips as measurement tools, while the remaining studies made use of 3D microsensors for their assessments. In the context of fixed appliances, key findings included a high level of agreement in 3‐dimensional orthodontic force detection between simulation results and actual applied forces. Incorporating critical force‐moment combinations during smart bracket calibration reduced measurement errors for most components. Translational tooth movement revealed a moment‐to‐force ratio, aligning with the bracket's centre of resistance. The primary findings in relation to aligners revealed several significant factors affecting the forces exerted by them. Notably, the foil thickness and staging were found to have a considerable impact on these forces, with optimal force transmission occurring at a layer height of 150 μm. Furthermore, the type of material used in 3D‐printing aligners influenced the force levels, with attachments proving effective in generating extrusive forces. Deliberate adjustments in aligner thickness were observed to alter the forces and moments generated. Conclusions: Microchips and 3D sensors provide precise and quantitative measurements of orthodontic forces in in vitro studies, enabling accurate monitoring and control of tooth movement. [ABSTRACT FROM AUTHOR]

Background: Orthodontic appliances hinder proper oral hygiene, leading to plaque retention and biofilm formation which can cause dental diseases. This study investigates the initial impact of orthodontic treatment with fixed appliances versus clear aligners on microbial profiles and gingival/plaque indices. Methods: Nine patients were included in this small-scale prospective longitudinal pilot study – five in treatment with fixed appliances and four with clear aligners. Plaque biofilm samples were collected subgingivally, supragingivally and from clear aligner trays, and gingival and plaque indices were recorded at six timepoints over 3 months. DNA was extracted and next-generation 16S rRNA sequencing of the V4 region was performed. Results: Fixed appliance patients showed higher plaque and gingival index scores early on (p ≤ 0.05) and higher levels of oral pathogens (p ≤ 0.05). Microbiological analysis revealed distinct microbial communities on clear aligner trays, with health- and disease-associated microbes present at significantly different levels (p ≤ 0.05) compared to intraoral plaque samples. Conclusions: Patients undergoing orthodontic therapy with fixed appliances had higher levels of plaque retention and oral pathogens. Clear aligner patients' had microbial profiles with more oral health-associated species and lower gingival/plaque indices. However, the biofilm on clear aligner trays requires further study, and the small sample size limits the conclusiveness of all findings. Implications: Dentists may consider clear aligners as an alternative to fixed appliances, with potential benefits in plaque accumulation and oral microbial composition. All patients undergoing orthodontic therapy should practice good oral hygiene to prevent plaque retention and reduce oral pathogen colonization. Continuing Education Credit Available: A CDA Continuing Education quiz is online for this article: The practice worksheet is available online: [ABSTRACT FROM AUTHOR]

Featured Application: Control of the wearing process of clear aligners and resulting consequences of their improper functioning. This paper investigates the evolution of the outer surface geometry of Invisalign®—clear orthodontic aligners—caused by degradation triggered by wearing. The obtained results served to confirm whether or not the aligners could continue to be used once their wear time in the therapeutic procedure had ended, taking both their geometric and mechanical features into account. The measurements were performed using atomic force microscopy which allowed the mapping of nanomechanical properties. The obtained images were then processed to determine statistical and functional surface geometry parameters in accordance with relevant ISO standards. The results revealed that the unrepeatability of the manufacturing process causes the surface shape parameters of new aligners to be irregular; however, these features become gradually consistent for worn samples. On the other hand, properly used aligners may change in two ways: the outer layer flattens and its thickness decreases, and at the same time the Young's modulus of the material decreases. It follows that the degradation processes may be caused by tribological phenomena (abrasion of contact surfaces) and/or biochemical phenomena (biofilm growth, decomposition of the material under the influence of enzymes in the oral cavity). [ABSTRACT FROM AUTHOR]

Introduction: Although with increasing popularity due to aesthetic appeal and comfort, clear aligners (CAs) are facing challenges in efficacy and predictability. Advancement in the underlying biomechanical field is crucial to addressing these challenges. This paper endeavors to provide a comprehensive framework for understanding the biomechanics of CA and enlightening biomechanics-based improvements on treatment strategies. Methods: A thorough review of the English-language literature accessible through PubMed and Google Scholar, without any publication year restrictions, was undertaken to unravel the biomechanical aspects of CA. Results: This review presented an up-to-date understanding of aligner biomechanics arranged by the framework of the material-dependent mechanical characteristics of CA, the geometric characteristics-dependent force transmission of the CA system, methods for studying the biomechanics of CA, and the biomechanical analyses for different types of tooth movement. Conclusions: Biomechanics should be the fundamental concern for concepts, methods and adjuncts attempting to enhance the accuracy and predictability of tooth movement induced by CA. Improvement on material properties and alteration of geometric design of CA are two main approaches to develop biomechanically optimized force system. Exploration of real-world force sensing and monitoring system would make substantial progresses in aligner biomechanics. [ABSTRACT FROM AUTHOR]

The era of printed aligners has just began in the orthodontic field. Orthodontists have become more interested in 3D-printed in-office aligners. Treatment due to this technology can become faster and more efficient. Advantages highlighted by newly introduced materials for manufacturing processes of 3D aligners present the possibility of overcoming limitations faced by thermoformed aligners, making them a potential replacement of thermoformed aligner. Advances in aligner material, especially shape memory polymers, have the potential to bring about radical transformations in the clinical applications of clear aligner therapy. Safety and cytotoxicity of printable resins along with its mechanical properties must be scientifically studied extensively before it is cleared for clinical use. In addition, with the increased use of aligners, awareness of the environmental burden of plastic waste should be emphasized. Attention should be directed into the development of recyclable materials for aligners along with establishing clear recycling guidelines and patient education programs on proper recycling methods. With the introduction of Graphy's clear biocompatible photocurable resin, which is equipped with a shape–memory function and is printed in an environmental friendly way by reducing carbon emissions. Direct 3D printing represents the future of clear aligner therapy, and more studies to test these new technologies and materials are required. [ABSTRACT FROM AUTHOR]

Clear aligner therapy is a rapidly developing orthodontic treatment. 3D-printing technology, which enables the creation of complex geometric structures with high precision, has been used in dentistry. This article aims to summarize the various aspects of 3D-printing clear aligners and give an outlook on their future development. The traditional thermoforming technology is introduced and the principle and application of 3D-printed clear aligners and materials are introduced, as well as the application prospects of 3D-printed clear aligners. According to PRISMA statement, the relevant literature of 3D-printing clear aligner was searched in PubMed, Web of Science, Embase and other databases. We searched the related words in the MESH database and then carried out advanced searches. We read systematic review and conference papers to find the articles related to the subject and manually added and excluded articles by reading the title and abstract. The production of clear aligners combines computer-aided 3D analysis, personalized design and digital molding technology. The thickness and edges of the 3D-printed clear aligner can be digitally controlled, which allows appliance more efficiently fitted. Presently, the array of clear resins suitable for 3D-printing include photo polymeric clear methacrylate-based resin (Dental LT) (Form Labs, Somerville, Mass), aliphatic vinyl ester-polyurethane polymer (Tera Harz TC-85) (Graphy, Seoul, South Korea). They all have good biocompatibility. But no such material is currently approved on the market. Developing biocompatible resins and further improving the material's mechanical properties will be critical for the combination of 3Dprinting and clear aligners. However, the literature on 3D-printed clear aligners is limited and lacks clinical application. Further in vivo and in vitro tests, as well as additional exploration in conjunction with corresponding cytological tests, are required for the research on available materials and machinery for 3D-printing clear aligners. [ABSTRACT FROM AUTHOR]

Although molar distalization is one of the most difficult movements to achieve with conventional orthodontic treatment, it has been reported that it is one of the most predictable movement when using clear aligners. The aim of this systematic review is to assess the efficiency of molar distalization using clear aligners, and to evaluate the associated effects of this treatment. Pubmed, Scoups, science direct, Web of Science, and EBSCO databases were searched up to May 2023 for randomized controlled trials (RCTs) and non-randomized prospective and retrospective studies on maxillary and lower molar distalization using clear aligner. Ten studies were included in the systematic review, two prospective nonrandomized and eight retrospective non-randomized. The predictability of molar distalization ranges from 31.1% to 87%, with good control of the vertical dimension and tipping movements. The lower molar distalization is mainly a tipping movement rather than bodily movement. Molar distalization using clear aligners appears to be effective, although variations in study protocols may contribute to differences in predictability rates. Randomized controlled trials with standardized protocols are therefore needed to provide more accurate assessments. [ABSTRACT FROM AUTHOR]

Background: The aim of the present study was to compare the vertical dimension changes, before and after treatment, in two groups of growing patients, one group treated with clear aligner therapy versus a group treated with Quad-helix and bite-block therapy. Methods: The studied sample was composed of n. 40 patients (20 females and 20 males with a mean age of 8.6 ± 1.8 years), enrolled from the Department of Orthodontics at Policlinico of Rome Tor Vergata. The original sample was randomly divided into two groups: Group IF (Invisalign First) and Group BB (Quad-helix and bite block). Pre- (T0) and post-treatment (T1 after 12 months) lateral cephalograms were collected from all the selected patients. Nine cephalometric parameters, both angular and linear, were measured and recorded for each cephalogram. Results: No statistically significant changes were found between both the IF and BB groups at T0, while statistically significant changes were observed in both groups (BB and IF) between T0 and T1 (after 12 months of active therapy), p < 0.005. Conclusions: Both therapies were able to control the patient's vertical condition. To date, the use of conventional appliances seems to have slightly better efficacy in controlling the vertical dimension than aligner therapy. [ABSTRACT FROM AUTHOR]

In invisible orthodontics, the role of composite attachments in facilitating complex tooth movements is crucial. This study, which evaluates the efficacy of a novel clinical attachment procedure, holds significant implications for the field. The technique used two templates (one pre-drilled and the other pre-loaded with high-viscosity composites) and was compared with the standard procedure. Fifty attachments were planned for four dental arch prototypes. Dental impressions were taken using digital scans for virtual planning and after tested techniques. The stereolithographic files (STL) obtained were aligned with those of the virtual planning, and a colorimetric map was used to evaluate the composite resin's maximum excess and defect deviation. The enamel–resin interfaces were observed by scanning electron microscopy (SEM). The Fisher test for the distribution of detachments and morphological defects and the Mann–Whitney test for the maximum values of excess and defect were used. No significant results were found between groups for morphological defects and detachments, and the maximum values of defect and excess were reported. SEM images for the experimental technique showed integrated adhesion. This innovative procedure, which has proven reliable and operationally straightforward, holds promise, instilling confidence in its practicality and potential to advance the field of orthodontics. [ABSTRACT FROM AUTHOR]

This study aimed to optimize space closure efficiency by comparing the forces and moments exerted by different designs of clear aligners (CAs) during the movement of maxillary canines into the premolar extraction space. The forces and moments were measured using a multi-axis force/moment transducer on the maxillary right canine. The CAs were fabricated from thermoformed polyethylene terephthalate glycol. The following four edentulous space designs were tested: the edentulous space was left intact (Group 1); the edentulous space was replaced with a premolar pontic (Group 2); the edentulous space was replaced with a half-sized premolar pontic (Group 3); and the edentulous space was replaced with a rectangular column beam (Group 4). The maxillary right canine was moved 0.25 mm distally. All groups experienced buccodistal and intrusive forces; compared with the other groups, Group 1 showed significantly greater intrusive and smaller distal forces, and Group 4 showed significantly greater distal forces. All groups experienced distal tilting, lingual inclination, and mesial rotational moments. These findings suggest that modifying the thickness and extent of the adjacent teeth in the edentulous area of the CA can improve local stiffness, thereby reducing the tipping of the teeth into the edentulous space. This study emphasizes the importance of the CA design in controlling forces and moments for effective orthodontic treatment. [ABSTRACT FROM AUTHOR]

The increasing concern over environmental sustainability has prompted various industries to reassess their practices and explore greener alternatives. Dentistry, as a significant contributor to waste generation, is actively seeking methods to minimize its environmental footprint. This paper examines the environmental implications of clear aligner therapy (CAT) in orthodontics and explores strategies to prioritize sustainability in aligner manufacturing and usage. CAT has gained popularity as a viable alternative to traditional fixed appliances due to advancements in biomaterials and computer-aided design (CAD) and manufacturing (CAM) technologies. The global market for clear aligners is expanding rapidly, with significant growth projected in the coming years. To address these challenges, this paper proposes adopting the principles of reduce, reuse, recycle, and rethink (4Rs) in orthodontic practices. Strategies such as minimizing resource consumption, incorporating recycled materials, and promoting proper aligner disposal and recycling can significantly reduce environmental harm. This paper explores emerging technologies and materials to mitigate the environmental impacts of CAT. Additionally, initiatives promoting aligner recycling and repurposing offer promising avenues for reducing plastic waste and fostering a circular economy. In conclusion, while CAT offers numerous benefits in orthodontic treatment, its environmental impact cannot be overlooked. By implementing sustainable practices and embracing innovative solutions, the orthodontic community can contribute to a more environmentally conscious future while continuing to provide quality care to patients. [ABSTRACT FROM AUTHOR]

This study aimed to compare the color changes in two different orthodontic clear aligner systems after submersion in various beverages for 14 days. The tested aligner systems were Taglus Premium made of polyethylene terephthalate glycol (the TAG group) and CA® Prodin+ made of a transparent copolyester and a thermoplastic elastomer (the PRO group). A total of 56 samples were firstly divided into two groups according to the tested system—TAG and PRO. Each group was subsequently divided in four subgroups according to immersion solution: A—artificial saliva, B—cola, C—coffee, D—red wine. Color measurements were performed on Days 1, 7 and 14 using a portable colorimeter and the CIE L*a*b* system. The obtained results showed significant color changes in both materials when exposed to coffee and red wine (p > 0.05). Samples in the PRO group showed a greater susceptibility to discoloration (higher ΔE values) when compared to the TAG group after submersion in cola (p = 0.025), coffee (p = 0.005) and red wine (p = 0.041) solutions. Statistical analysis revealed that all of the color parameters ΔL*, Δa*, Δb* and ΔE of both tested materials were affected by submersion in coffee solution for 14 days. In conclusion, the CA® Pro+ aligner system is more prone to staining compared to the Taglus material after submersion for 14 days in cola, coffee and red wine solutions. Submersion for 14 days in coffee solution alters all of the color parameters (ΔL, Δa, Δb and ΔE) of both tested aligner materials. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the effects of different attachment configurations with and without buccal root torque on expansion movements achieved with aligners through finite element analysis (FEA). Methods: FEA modelling was done with 0.25 mm buccal expansion force application to the maxillary molars with different attachment configurations: Eight models were tested (1) no attachment (NA), (2) horizontal attachment (HA), (3) gingivally beveled horizontal attachment (GHA), and (4) occlusally beveled horizontal attachment (OHA), as well as models with 6obuccal root torque, (5) no attachment (TNA), (6) horizontal attachment (THA), (7) gingivally beveled horizontal attachment (TGHA), and (8) occlusally beveled horizontal attachment (TOHA). Results: The first and second molars exhibited buccal tipping in all models. The highest amount of buccal tipping for the molars was observed in the NA (6CMB, 0.232 mm; 6CMP, 0.246 mm; 7CMB, 0.281 mm; 7CMP, 0.312 mm) and GHA (6CMB, 0.230; 6CMP, 0.245; 7CMB, 0.279 mm; 7CMP, 0.311 mm) models, respectively, while the least tipping was observed in the TOHA model (6CMB, 0.155 mm; 6CMP, 0.168 mm; 7CMB, 0.216 mm; 7CMP, 0.240 mm). In all groups, the buccal tipping of the second molars was higher than that of the first molars. Conclusion: This FEA study showed that expansion with aligners tip maxillary molars buccally and the use of occlusally beveled attachments and addition of buccal root torque reduces uncontrolled buccal tipping. [ABSTRACT FROM AUTHOR]

Introduction: To evaluate biomechanics of an aligner utilizing divots and the effect of their vertical placement on the right maxillary central incisor. Methods: An in vitro Orthodontic SIMulator (OSIM) was used to test forces and moments generated by aligners incorporating divots. The OSIM arch was scanned to generate a. STL version that was modified to create four models by placing divots on different positions of the right central maxillary incisor: GI – divots on gingival‐third of lingual surface and incisal‐third of labial surface; GM – divots on gingival‐third of lingual surface and middle‐third of labial surface; MI – divots on middle‐third of lingual surface and incisal‐third of labial surface; MM – divots on middle‐third of lingual surface and middle‐third of labial surface. Aligners (n = 30/model) were fabricated using a 0.75 mm thick polyethylene terephthalate material and Biostar® machine following the manufacturer's recommendations. A one‐way MANOVA followed by one‐way ANOVA (α = 0.05) was utilized to test effect of models on buccolingual force (Fy) and mesiodistal moment (Mx) at 0.20 mm of lingual displacement of the right maxillary central incisor. Results: Mean Mx for GI (−5.68 ± 7.38 Nmm), GM (3.75 ± 5.54 Nmm), MI (−4.27 ± 1.48 Nmm) and MM (1.96 ± 0.99 Nmm) models showed statistical differences between GI and GM, GI and MM, GM and MI and MI and MM. GI exerted the largest Fy (1.87 ± 0.75 N) followed by GM (1.10 ± 0.47 N), MI (0.70 ± 0.23 N) and MM (0.28 ± 0.08 N) with significant differences between GI and GM, GI and MI, GI and MM and GM and MM models. Conclusions: Vertical divot placement on a right central incisor had a significant effect on aligner biomechanics. Buccolingual forces exerted by models GI, GM and MI were within the range suggested by literature for bodily tooth movement without major root tipping for GM and MI models. [ABSTRACT FROM AUTHOR]

Background: Desirable molar distalization by bodily movement is challenging and can be difficult to achieve. This study investigated changes in molar angulation (mesiodistal tipping), molar inclination (buccolingual torque) and rotation during distalization using clear aligner therapy (CAT). Materials and methods: This retrospective study included 38 cone beam computed tomographic images (CBCTs) taken for patients treated with molar distalization using CAT. The study evaluated pre- (T0) and post-treatment (T1) CBCTs of 19 adult patients (36.68 ± 13.50 years) who underwent maxillary molar distalization using Invisalign® aligners (Align Technology, Inc., San José, CA, USA) with a minimum of 2 mm distalization. Changes in maxillary molar tip, torque and rotation were measured for 61 molars (183 roots). Paired t-test was used to evaluate the differences between pre- and post-treatment readings. The level of significance was set at p ≤ 0.05. The reproducibility of measurements was assessed by the intraclass correlation coefficient (ICC). Results: Molar angulation did not show significant change after distalization (p = 0.158) however, there was significant increase in buccal molar inclination (p = 0.034) and mesiobuccal molar rotation (p < 0.001). Conclusion: Molar distalization of 2 mm did not cause significant molar tipping. Maxillary molars showed significant buccal inclination (increased torque) and mesiobuccal rotation after distalization. [ABSTRACT FROM AUTHOR]

Background: Clear aligner treatments have gained popularity due to their aesthetic advantages over traditional metal brackets. Attachments play a crucial role in enhancing the efficacy of treatment by addressing challenges posed by the flexibility of aligner materials. This comprehensive review aims to clarify the significance of attachments used during clear aligner therapy and explore the nuances of their design, placement, and material selection. Methods: A systematic search of literature databases including Web of Science, PubMed, Scopus, Google Scholar, and Cochrane was conducted. Twelve sets of keywords related to clear aligner therapy and attachments were applied for the search. Results: A total of 24 studies that met the inclusion criteria and focused on the biomechanics of attachments, attachment shape, attachment placement and materials used in attachment production were included in the analysis. Conclusion: Within the limits of the review, the use of attachments in clear aligner therapy can enhance the efficacy of treatment by facilitating complex tooth movements. The selection of materials, as well as the design and positioning strategies of attachments, should be customised for each patient to optimise treatment success. By the use of clinical studies, future research should focus on the long-term performance of attachments to confirm their effectiveness in achieving planned tooth movements, particularly regarding design, positioning, and the materials used. [ABSTRACT FROM AUTHOR]

Clear aligners seem to be a new modality for patients undergoing orthodontic treatment; the initial concept of this treatment evolved in the 20th century. Remensnyder's "Flex-O-Tite" appliance led to the introduction of the aligner, from this Kesling tooth positioner appliance made up of rubber-based 1945 proposed the concept of using it for minor tooth movements in a sequential series. The purpose of this article is to provide information about chronologically ordered evolution of aligners. Various types of generations and attachments used in different aligner systems. An online search was done using databases from PubMed and Google Scholar to find the articles. Database search was done with the following string: ((aligners [Title/Abstract]) AND (comparison [Title/Abstract])) AND (((fixed appliance [Title/Abstract]) OR (braces [Title/Abstract])) OR (fixed orthodontic appliance [Title/Abstract])). 3 articles are included in the narrative review to evaluate the better outcomes of the treatment effectiveness between fixed orthodontic treatment and aligners with short summary of chronological ordered evolution, generations and attachments of aligners. The overall effectiveness of orthodontic treatment depends upon the knowledge of clinician therefore knowledge about recent advances is important for proper treatment of the patient. [ABSTRACT FROM AUTHOR]

Nowadays, aligners represent a possible therapeutical approach that combines both esthetic and function in order to address dental malocclusion. However, they require a significant level of compliance from the patient. According to the manufacturer, at least 22 h of wearing a day is demanded to reach the optimal therapeutical level; hence, aligners can only be removed during meals. Patients' compliance might increase and the duration of the treatment might decrease if they were allowed to eat with aligners on. The idea of patients keeping the aligners on during meals has been contemplated, not only to favor patients' compliance but also treatment effectiveness. This study aims to assess the degree of chewing difficulty that aligners cause when eating certain kinds of food and the quantity of residue left. Material and Methods: A questionnaire titled "Questionnaire for the Assessment of Masticatory Function with Aligners" was administered using Google Forms to 240 patients in treatment with clear aligners. The survey was validated through the reliability test using the test–retest method. This method had a higher correlation coefficient of 0.9 across all items (with a cutoff of 0.8) with statistical significance, and an excellent internal correlation coefficient (α > 0.9). The statistical analysis performed consisted of descriptive analysis, frequencies, percentages, Pearson's correlation test and Friedman's test. Results: Pearson's test showed a statistically significant correlation between all items except between meat or clams and yogurt or ice cream and with mozzarella or soft cheese regarding food chewing difficulties. Pearson's test showed a statistically significant correlation between all items regarding food residues. A total of 69.2% of the cohort reported some movements of aligners during mastication. In total, 88.3% of them affirmed not to have perceived deformations or breakage of aligners during chewing. Furthermore, 79.2% of them declared that they would continue to eat if eating with aligners was proven to speed up treatment. Conclusions: Wearing clear aligners while chewing foods such as yogurt, ice cream, soft cheese, bread, rice, etc., can be possible and can help shorten the duration of orthodontic treatment, benefiting both the patient and the orthodontist. However, further research using qualitative methods is needed to understand the barriers and facilitators to chewing food with aligners. [ABSTRACT FROM AUTHOR]

Background and Objectives: To compare the oral-health-related quality of life (OHRQoL) outcomes between patients treated with modified Ni-Ti spring-based alignment appliances or conventional fixed appliances using the Oral Health Impact Profile 14 (OHIP-14), as well as the levels of satisfaction with the appliance appearance, treatment progress, and outcomes. Materials and Methods: Thirty-six patients (11 males, 25 females) were randomly divided into two groups: either the modified aligner appliance with Ni-Ti springs group (MAA) or the traditional fixed appliances group (FA). The allocation ratio was 1:1, and the randomization process was carried out by an independent investigator not involved in this study. Mild crowding cases were included in this study. The OHRQoL of patients was evaluated using the short-form Oral Health Impact Profile (OHIP-14) at five time points: before the treatment commencement (T0); 2 weeks (T1), 1 month (T2), and 2 months (T3) after the treatment initiation; and post-treatment (T4). The visual analog scale (VAS) was used to evaluate the patient satisfaction. Blinding was performed only during the outcomes assessment. Results: This randomized controlled trial had no dropouts, and the demographic characteristics of the groups were comparable. The MAA group experienced significantly greater functional limitations compared with the FA group at all three evaluation time points (T1, T2, and T3), as evidenced by the statistically significant p-values (p = 0.004, p = 0.001, and p < 0.001, respectively). The psychological disability in the MAA group was significantly lower than in the FA group at both T2 (p = 0.005) and T3 (p = 0.003). The patient satisfaction with the appliance appearance was significantly higher in the MAA group than in the FA group (p = 0.002). Conclusions: The OHRQoL improved in both the modified aligner appliance with Ni-Ti springs and fixed appliance groups after the treatment. Moreover, the functional limitations during the treatment were less severe in the FA group, while the psychological disability was lower, and the patient satisfaction with the appliance appearance was higher in the MAA group. [ABSTRACT FROM AUTHOR]

(1) Background: PETG (polyethylene terephthalate glycol) is a transparent, inexpensive, and versatile thermoplastic biomaterial, and it is increasingly being used for a variety of medical applications in dentistry, orthopedics, tissue engineering, and surgery. It is known to have remarkable properties such as tensile strength, high ductility, and resistance to chemical insults and heat, but it can be affected by various environmental conditions. The aim of the present study was to evaluate the topographical characteristics of four thermoplastic dental appliance materials in relation to water sorption in simulated oral environments (artificial saliva samples with different pH values). (2) Methods: The following four types of PETG clear thermoplastic materials were selected for the present study: Leone (L), Crystal (C), Erkodur (E), and Duran (D). In relation to the desiccation and water-uptake stages, their water sorption (Wsp) and solubility (Wsl) were calculated, and the surface topographies were analyzed on two length scales. The surface roughness was determined using a contact profilometer, and nanoroughness measurements were generated by three-dimensional profiles using an atomic force microscope (AFM). Statistical analyses (one-way ANOVA and unpaired and paired Student t-tests) were performed. (3) Results: After saliva immersion, the weights of all samples increased, and the highest sorption was recorded in a basic environment. Among the materials, the water uptake for the L samples was the highest, and for E, it was the lowest. In relation to water solubility, significant values were registered for both the L and C samples' materials. After immersion and desiccation, a decreasing trend in microroughness was observed. The AFM high-resolution images reflected more irregular surfaces related to saliva immersion. (4) Conclusions: The sorption rates recorded in water-based artificial saliva were higher for basic pH levels, with significant differences between the samples. There were also significant differences related to the behaviors of the materials included in the study. In relation to roughness, on a microscale, the surfaces tended to be smoother after the saliva immersions, and on a nanoscale, they became more irregular. [ABSTRACT FROM AUTHOR]

Aesthetic demand and patients' needs have been the priority for orthodontic treatment. With the introduction of Clear aligners in the market the aesthetic needs of the patients have been highly satisfied. Clear aligner fabrication has been evolving with technology since its introduction, indirectly printed aligners have been fabricated on 3D printed models for years now. Recently, directly printed aligners have been introduced in the market easing the fabrication process by eliminating the fabrication of 3D printed models and hence overcoming the shortcomings of the 3D printed thermoformed aligners. Various resins have been introduced since the introduction of the concept of directly printed aligners. This article covers the various resins available in the market and the literature regarding the same. Studies have been performed to understand the mechanical properties of these materials and it has been found that further refinements and improvements are required. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to clarify the applied initial forces and moments by different aligners of various materials and manufacturing methods., Methods: The finite-element-method was used to analyze the forces and moments generated by the aligners on a maloccluded tooth. Plaster models of dental arches with a mesiorotated tooth 11 were fabricated, digitized and virtually analyzed. Four types of aligners with various layer thicknesses were selected: two splints with novel shape memory properties: a printable aligner made of the resin Tera Harz TC-85 DAC (Graphy Inc., South Korea) and a self-manufactured aligner consisting of the components polypropylene carbonate and thermoplastic polyurethane. The other two aligners were conventional, thermoformable aligners: CA ® Pro Clear Aligner (Scheu Dental GmbH, Germany) and Erkodur-al (Erkodent Erich Kopp GmbH, Germany)., Results: The force and moment analyses showed that the thermoformable CA ® Pro Clear Aligner exhibited the highest values. The thermoformed Erkodur-al aligner showed the lowest force loads for all layer thicknesses. The Graphy printed splint showed similar results compared to Erkodur-al at layer thicknesses of 0.40 mm and 0.50 mm., Conclusions: To avoid periodontal overloading, aligners with lower force and moment delivery should be chosen for this type of tooth movement., (© 2025 the author(s), published by De Gruyter, Berlin/Boston.)

The objective of the presented study was to evaluate the biomechanics of aligners utilising attachments and the effect of their placement for extrusion. An in vitro Orthodontic SIMulator (OSIM) was used to measure forces and moments produced through aligners incorporating attachments. The maxillary teeth on OSIM were digitally scanned to generate an STL model that was modified by placing a rectangular shaped attachment. Four models were designed with variation in attachment placement: Model NA-no attachment; model BA-buccal attachment; model LA-lingual attachment; model BL-both buccal and lingual attachments. Aligners (n = 30/model) were fabricated using a 0.75 mm thick polyethylene terephthalate material using a Biostar machine following the manufacturer's recommendations. A one-way MANOVA, followed by one-way ANOVA was used to test the effect of models on occlusogingival force (Fz) and mesiodistal moment (Mx) at 0.20 mm of gingival displacement of the left lateral incisor. The BL model exerted maximum Fz (1.22 ± 0.20 N), followed by models BA (1.18 ± 0.25 N) and LA (1.07 ± 0.19 N). The model NA exerted a negligible Fz (0.14 ± 0.08 N) that was statistically different from all other models. The models BA and LA generated Mx that has the tendency to tip the crown of tooth lingually (10.00 ± 3.12 Nmm) and buccally (-1.29 ± 2.26 Nmm), respectively. The models show statistically significant differences between models BL, BA and LA. There was no statistically significant difference between models BL and NA. The experimental evidence suggest that attachments on the lateral incisor could improve the predictability of extrusion forces applied with aligners. The models BL and LA provided favourable biomechanics by generating clinically significant extrusion forces without significant tipping of the lateral incisor tooth., (© 2025 The Author(s). Orthodontics & Craniofacial Research published by John Wiley & Sons Ltd.)

Introduction: Metallic and elastomeric ligatures are widely used in orthodontics to secure the archwire within the bracket slots, but elastomeric ligatures have traditionally been associated with increased microbial colonization, which could adversely affect periodontal health. Aim: This systematic review compares the periodontal effects of elastomeric and steel ligatures used for orthodontic fixed appliances. Methods: Unrestricted literature search of 7 databases (MEDLINE, Scopus, Web of Science, Embase, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, and Virtual Health Library) up to July 2023 were performed for randomized / non-randomized clinical studies on humans comparing the two ligation methods during fixed-appliance therapy. After duplicate study selection, data extraction, and risk-of-bias assessment with the Risk of Bias (RoB) 2 or the Risk Of Bias In Non-randomized Studies - of Interventions (ROBINS-I) tool, random-effects meta-analyses of Mean Differences (MD) or Standardized Mean Differences (SMD) and their 95% confidence intervals (CIs) were carried out, followed by assessment of certainty of existing evidence with the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) approach. Results: A total of 11 studies (3 randomized / 8 non-randomized) with 354 patients (mean age 14.7 years and 42% male) were included. No statistically significant differences were seen for plaque index (5 studies; SMD = 0.48; 95% CI = -0.03 to 1.00; P = 0.07), gingival index (2 studies; MD = 0.01; 95% CI = -0.14 to 0.16; P = 0.89), probing pocket depth (2 studies; MD = 0; 95% CI = -0.17 to 0.16; P = 0.97), or Streptococcus mutans counts (4 studies; SMD = 0.40; 95% CI=-0.41 to 1.20; P = 0.21). Elastomeric ligatures were associated with moderately increased total bacterial load (3 studies; SMD = 0.43; 95% CI = 0.10 to 0.76; P = 0.03). Confidence in these estimates was low in all instances due to the inclusion of non-randomized studies with high risk of bias. Conclusions: Existing low quality evidence indicates that ligature method does not seem to influence the periodontal health during fixed treatment, even if elastomeric ligatures are associated with a moderate increase of bacterial load. Registration: PROSPERO (CRD42023444383) [ABSTRACT FROM AUTHOR]

Patients seeking orthodontic treatment often prioritize aesthetics, and aesthetics play a significant role in orthodontic care. Researchers have developed a range of options, such as ceramic or composite braces, lingual orthodontics, and transparent aligners, to meet the growing demand for alternatives to traditional braces. Clear aligner therapy, which consists of a series of transparent dental appliances designed to fit the shape of a patient's teeth, is one such alternative. Clear aligners, like traditional braces, use a progressive force to control tooth movement, but they do so without metal brackets or wires. This review will highlight the increasing popularity of clear aligners by summarizing a few commonly used systems today. It will also discuss the therapeutic outcomes of this approach, including its scope, limitations, effectiveness, and stability. Additionally, the review will evaluate the potential negative effects of clear aligner therapy. [ABSTRACT FROM AUTHOR]

Background: The introduction of auxiliaries such as composite attachment has improved the force delivery of clear aligner (CA) therapy. However, the placement of the attachment may give rise to a flash, defined as excess resin around the attachment which may affect CA force delivery. This in vitro study aims to determine the differences in the force generated by the attachment in the presence or absence of flash in CA. Materials and methods: Tristar Trubalance aligner sheets were used to fabricate the CAs. Thirty-four resin models were 3D printed and 17 each, were bonded with ellipsoidal or rectangular attachments on maxillary right central incisors. Fuji Prescale pressure film was used to measure the force generated by the attachment of CA. The images of colour density produced on the films were processed using a calibrated pressure mapping system utilising image processing techniques and topographical force mapping to quantify the force. The force measurement process was repeated after the flash was removed from the attachment using tungsten-carbide bur on a slow-speed handpiece. Results: The intraclass correlation coefficient showed excellent reliability (ICC = 0.96, 95% CI = 0.92–0.98). The average mean force exerted by ellipsoidal attachments with flash was 8.05 ± 0.16 N, while 8.11 ± 0.18 N was without flash. As for rectangular attachments, the average mean force with flash was 8.48 ± 0.27 N, while 8.53 ± 0.13 N was without flash. Paired t-test revealed no statistically significant difference in the mean force exerted by CA in the presence or absence of flash for both ellipsoidal (p = 0.07) and rectangular attachments (p = 0.41). Rectangular attachments generated statistically significantly (p < 0.001) higher mean force than ellipsoidal attachments for flash and without flash. Conclusion: Although rectangular attachment generated a significantly higher force than ellipsoidal attachment, the force generated by both attachments in the presence or absence of flash is similar (p > 0.05). [ABSTRACT FROM AUTHOR]