The aim of this study was to clarify the applied initial forces and moments by different aligners of various materials and manufacturing 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).

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.

To avoid periodontal overloading, aligners with lower force and moment delivery should be chosen for this type of tooth movement.

The dentoskeletal effects of clear aligner treatment (CAT) with Invisalign vs temporary skeletal anchorage device-anchored Sydney intrusion spring (SIS) were compared in consecutively treated growing patients with anterior open bite using cone-beam computed tomography scans.

Fifteen adolescents treated exclusively with Invisalign, and 14 with SIS (first-phase treatment) were assessed retrospectively. Rigid-wise, voxel-based registration of pretreatment and posttreatment cone-beam computed tomography scans were performed using the anterior cranial base, maxillary plane, and mandibular body as reference regions. Treatment outcomes were compared between groups using median regression modeling.

Molar intrusion and incisor extrusion (millimeters), as well as buccolingual inclination changes (°), were not expressed as prescribed in the ClinChecks for Invisalign. Both treatment modalities resulted in similar improvement of anterior open bite; however, via different mechanics. Compared with CAT, SIS demonstrated significantly greater intrusion of the maxillary first molars when measured from the mesiobuccal (16: 2.09 mm [95% confidence interval {CI}, 1.05-3.12]; 26: 2.98 mm [95% CI, 2.00-3.96]) and palatal cusps (16: 2.08 mm [95% CI, 1.15-3.01], 26: 2.83 mm [95% CI, 1.92-3.74]) and less extrusion of the maxillary incisors (12: -1.30 mm [95% CI, -2.13 to -0.47], 11: -1.30 mm [95% CI, -2.40 to -0.20], 21: -0.92 mm [95% CI, -1.73 to -0.12], 22: -0.85 mm [95% CI, -1.71 to -0.00]). There was weak evidence of association with less extrusion of the mandibular incisors using SIS. Maxillary and mandibular incisors tipped lingually in both groups with no statistical difference across groups.

SIS demonstrated greater maxillary molar intrusion, whereas CAT was associated with incisor extrusion.

To measure the actual moving direction and displacement of the root and crown of maxillary teeth before and after treatment in molar distalization cases using clear aligners(CAs).

This retrospective study included 28 adult patients who received maxillary distalization treatment with CAs. The pre- and post-treatment CBCT were superimposed and the crown and root of all maxillary teeth were marked. Achieved and predicted three-dimensional displacement of maxillary teeth were then compared using the paired t test. Mixed-effect model was used to explore the influence of different staging design (one-molar distalization vs. two-molar distalization) and anchorage (TAD vs. Class II elastic vs. no extra anchorage management).

Labial displacement happened to the anterior teeth even the palatal displacement was prescribed. Body distalization of maxillary posterior teeth could not be fully achieved as predicted. The premolars and molars achieved greater distal tipping, buccal inclination, and less distal displacement than predicted. In buccal-palatal dimension, the greatest buccal tipping tendency happened to the 2nd premolar and decreased toward the distal portion of the aligner. In the mesial-distal dimension, the highest accuracy of molar distalization was found in the 2nd molars while the lowest in the 1st premolars. No significant difference was found between two molar distalization patterns. Extra anchorage management devices could not diminish the difference between the predicted and achieved displacement.

The achieved molar distalization displacement and anterior teeth retraction is not as good as expected using CAs. The anterior and posterior anchorage loss cannot be completely avoided despite extra anchorage management devices are adopted. The potential reason for the correction of class II malocclusion needs further exploration.

The widespread adoption of clear aligners in orthodontic treatments in recent years has necessitated a more precise examination of the mechanical properties of the devices currently available in orthodontics. Recent studies indicate that aligners, when exposed to the forces exerted during swallowing, undergo fatigue-like phenomena, leading to chip formation and cracks. The cumulative damage results in a compromised fit between the tooth and aligner, which is crucial for the effective execution of orthodontic treatment. Additionally, the formation of chips poses a potential risk to patients, as there is a possibility of inadvertently ingesting microplastics that become detached from the aligner over time. This study attempts to assess the release of microplastics from the aligners subjected to cyclic compressive loading. Three different aligners (Essix Ace, Ghost Aligner and Invisalign) are tested to simulate swallowing conditions over the aligner usage period. The mechanical performance is studied in terms of the energy absorbed by the aligner, which shows that the Essix Ace has a stable energy absorption behaviour, while the energy absorbed by the Invisalign is significantly higher than their counterparts. Ghost Aligner did not perform well in the cyclic compression tests. The microplastics (MPs) released by the aligners are examined under an optical microscope. A dimensional analysis based on k-means image segmentation and edge detection algorithm is developed to analyse the MPs. The dimensional analysis of the MPs revealed that the ingestion of the MPs released by all the three aligners does not pose a health risk.

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.

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).

The two-way interactions between group and tooth were significant (P<0.001) for all outcomes except facial/palatal moment around the X axis (Mx) (P>0.05). The horizontal ellipsoid attachment at the middle third generated the highest Mx (-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).

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.

The widespread adoption of clear aligners in orthodontic practice has driven the development of biomechanical devices to improve treatment efficiency. The mechanical properties of these materials play a critical role in determining their clinical performance and efficacy. This study investigates the Young's modulus of Clear-Blokker® (Scheu Dental), a photopolymerisable resin used for the attachment of clear aligner, and evaluates its mechanical behaviour under different curing times (5 s and 10 s) and environmental conditions (dry storage and immersion in artificial saliva at 37 °C).

Forty-eight cylindrical specimens were prepared and subjected to quasistatic compression tests after 14 days. A multi-factorial analysis of variance (ANOVA) at a significance level of 5% was performed to compare the variances.

The results showed that samples immersed in artificial saliva had significantly reduced Young's moduli compared to samples stored in dry conditions (p = 0.0213), while no significant difference was observed between curing times.

The results suggest that Clear-Blokker® has mechanical properties comparable to those of clear aligner materials, making it suitable as a biomechanical aid for orthodontic treatment. However, further clinical studies are required to confirm its long-term efficacy in the oral environment.

In orthodontic therapy, the periodontal ligament plays a critical role in the bone remodeling process by stimulating osteoblasts in tension zones and promoting bone resorption through osteoclasts in compression zones in response to mechanical stress. These processes are regulated by key cytokines, such as RANKL and IL-1, which are influenced by factors such as patient age and force application. This work evaluates the effectiveness of clear aligners versus traditional braces on periodontal health in patients with periodontitis, following PRISMA guidelines and utilizing specific inclusion and exclusion criteria.

A systematic review of 1664 records was conducted, leading to the inclusion of eight studies that focus on the impact of orthodontic treatments on periodontal health. The review identifies various biases present in the literature.

The findings reveal that clear aligners, in contrast to fixed appliances, improve oral hygiene and reduce inflammation, leading to better periodontal outcomes. Fixed appliances, on the other hand, may exacerbate plaque accumulation and inflammation, which can worsen periodontal health.

Clear aligners offer advantages over fixed appliances in terms of enhancing periodontal health, improving patient compliance, and providing long-term benefits, particularly in patients with severe periodontitis. The effectiveness of clear aligners is linked to better management of periodontal complications and overall oral hygiene. Treatment decisions should be based on patient-specific criteria to optimize outcomes.

This study aimed to evaluate the effects of attachment design on maxillary molar distalization and simultaneous expansion during distalization, and the influence of third molars on distalization in the clear aligner technique using the finite element method.

Six models were created to evaluate three different attachment designs on the second molars. Model I: employed a vertical rectangular attachment; Model II: used a vertical rectangular attachment with the presence of the third molar; Model III: used a combined semi-elliptical attachment; and Model IV: featured an opposed semi-elliptical attachment with buccal and palatal components. Models I through IV focused on distalization. Models V and VI were created by adding expansions to Models III and IV. The displacement amounts, clear aligner deformations, and stress distributions were analyzed using Ansys 19.2.

The presence of a third molar reduced maximum total displacement by 17%. Models I and III demonstrated similar distal displacement and tipping, both of which were more pronounced than in Model IV. Model IV achieved the most parallel tooth movement, with the least distal and buccal tipping and minimal distopalatal rotation. In the comparison of Models V and VI, Model VI exhibited greater distal and buccal displacements and more tipping than Model V.

The presence of a third molar reduced distalization efficiency and increased clear aligner deformation. For both movements, the attachment that provided the most parallel movement showed the least displacement. When selecting attachments, it is essential to consider factors such as tooth rotation, inclination, bone support, and root health.

This study introduced a novel force-driven automated staging design method for clear aligners, aimed at enhancing treatment planning efficiency and outcomes. The method simplified the alignment process into a force-driven mechanics model that calculates forces and moments exerted on teeth while adhering to Newton's third law, determining their displacement and rotation at each position. An optimal path was generated by iteratively moving teeth from their initial to target positions and subsequently divided into stages based on a predefined step size. The algorithm was implemented in C++ and incorporated into the WebGL-based SmarteeCheck3.0 software for visualization. In a maxillary extraction case, the automated staging method (0.25 mm step size) generated 51 stages in merely 5 s, while manual staging (>0.25 mm step size) necessitated 30 min to achieve 55 stages. In a molar distalization case, the automated method demonstrated similar efficiency advantages, generating 30 stages for the maxilla and 34 for the mandible, compared to 41 stages each in manual staging. The automated staging approach yielded shorter and more precise tooth movement paths that adhered to aligner biomechanics and physical principles, surpassing the limitations of manual staging. For cases requiring entire arch displacement, the method incorporated sequential movements with anchorage control to maintain force equilibrium. This innovative method substantially improved design efficiency and accuracy, ultimately elevating the efficacy of clear aligner therapy, although further biomechanical analyses and experimental validations are needed to refine the model parameters.

This study aimed to evaluate and compare the antibacterial properties and optical characteristics of clear orthodontic aligners coated with zinc oxide (ZnO) and magnesium oxide (MgO) nanoparticles.

In this experimental laboratory study, polyethylene terephthalate glycol (PETG) aligner samples were coated with nanoparticles of ZnO, MgO and a combination of both (ZnO + MgO). The surface coatings were analysed before and after stability testing using field emission scanning electron microscopy (FESEM). Colour changes and translucency were measured using a spectrophotometer, and the antimicrobial and antibiofilm properties were evaluated against Streptococcus mutans and Lactobacillus species. Statistical analysis was conducted using SPSS, with significance set at p < 0.05.

Significant statistical differences were found in the colour changes between the groups (p < 0.001), with the greatest change in MgO-coated aligners (0.94 ± 0.09), followed by ZnO + MgO (0.75 ± 0.05) and ZnO (0.5 ± 0.09). ZnO-coated aligners exhibited the highest translucency (47.6 ± 0.44) compared to MgO (45.07 ± 0.74) and ZnO + MgO (45.76 ± 0.7) (p = 0.002 and p = 0.026, respectively). Nanoparticle-coated aligners showed significantly reduced bacterial growth (p < 0.05). The ZnO + MgO combination demonstrated superior antibacterial effects compared to individual coatings. Nanoparticles remained stable after 24-h agitation in artificial saliva and brushing, maintaining 60%-65% stability.

The aligners coated with ZnO nanoparticles exhibited the least colour change and the highest translucency compared to those coated with MgO nanoparticles and the ZnO + MgO combination. The highest antibacterial properties were observed in the aligners coated with a combination of ZnO and MgO nanoparticles.

A simplified mechanics model of aligner-tooth interaction was developed to establish a precise computational method for overcorrection design in clear aligner orthodontics. Validated through finite element analysis and experiments, the results demonstrated that designing the movement of only the target teeth on the aligner leads to uneven force distribution on adjacent teeth, while an overcorrection design can evenly distribute the reaction force generated by pushing the target teeth to the anchorage teeth, reducing the maximum force on the anchorage teeth, minimizing unplanned tooth movement, and improving the efficacy of the designed tooth movement for all teeth.

This case report describes a complex full-step asymmetrical Class II division 1 high-angle in an adult patient treated by extraction of compromised first molars with a preadjusted lingual appliance. Since the patient presented severe sagittal and vertical discrepancies combined with an Izard orthofrontal profile with upper lip protrusion, an extraction camouflage was performed with the twofold aim of obtaining ideal occlusal relationship and profile improvement, correcting occlusal plane cant by selective intrusion with interradicular miniscrews. Appropriate biomechanical strategies, including extraction choice and anchorage control during space closure, were needed to achieve the planned results. This case report demonstrates the possibility of solving successfully severe sagittal and vertical discrepancies with significant asymmetric component in adult patient without surgical treatment by means of a completely invisible technique, with the extraction of the most compromised teeth in both arches. This report also underlines the need for careful planning during both diagnostic and treatment phases, with appropriate skeletal anchorage management, in order to obtain the best results.

This study developed an elastic silicone appliance material incorporating sodium fluoride (NaF) and evaluated its mechanical properties, biocompatibility, antibacterial effects, and remineralization potential.

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.

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.

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.

To investigate maxillary canine movement accuracy and anchorage during space closure in first premolar extraction cases (maximum anchorage) using In-House Clear Aligners (IHCAs).

A randomised controlled trial with a split-mouth design recruited 16 adults in university setting. Each patient was randomly assigned by side for canine retraction using 12 IHCAs to both the experimental palatal power arm (Pa) and non-Pa control (C). Accuracy was assessed using GOM Inspect by superimposing the virtual and actual digital models between pretreatment and 12th IHCA. Paired t-test or Wilcoxon signed-rank test was used to compare virtual-power arm (VPa) versus actual-power arm (APa) and virtual-control (VC) versus actual-control (AC). Root mean square error (RMSE) was calculated.

Pa displayed a significant difference in preliminary canine distalisation (VPa 2.0 mm vs. APa 2.4 mm), while the control did not differ. Both Pa and control exhibited significantly greater actual distal crown tipping than virtual movement (VPa 4.4° vs. APa -6.3°/VC 4.4° vs. AC -4.3°). AC achieved more canine rotation than VC. RMSE was slightly greater in Pa than control for canine distalisation (Pa 0.6 vs. C 0.55 mm) and distal crown tipping (Pa 10.9° vs. C 8.99°). Conversely, Pa displayed better accuracy in canine rotation. For anchorage, Pa and control exhibited significantly greater actual mesialisation and mesial tipping than virtual. RMSE for anchorage mesialisation and mesial tipping were comparable between Pa and control.

Preliminary canine retraction using Pa may result in greater error in distal crown tipping but less rotation than control.

ISRCTN 14020146 by the International Standard Randomised Controlled Trial Registry.

Clear aligner treatment (CAT) has emerged as an effective alternative to conventional multibracket systems in orthodontics. The trimline design and extension of aligners may significantly influence their biomechanical performance and tooth movement efficacy.

To systematically review the biomechanical effects of different aligner trimline designs and extensions on orthodontic tooth movement.

A systematic search was conducted across PubMed, Scopus, Embase, ProQuest Dissertations & Theses Global, and Google Scholar for studies published between January 2000 and August 2024. The review included any types of empirical research focusing on the influence of trimline of orthodontic aligners on tooth movement efficacy conducted between January 2000 and August 2024. The Risk of Bias In Non-randomized Studies of Interventions (ROBINS-I) tool was used for quality assessment.

Twelve studies met the inclusion criteria, all assessed as having low to moderate risk of bias. Aligner trimline design significantly influenced orthodontic tooth movement efficacy through two primary mechanisms: enhanced force delivery and increased aligner retention. Aligners with straight and extended margins generally exerted higher forces and moments compared to scalloped or shorter designs. This resulted in greater tooth displacement for certain movements, particularly intrusion, translation, tipping, and root torquing. Extended trimlines also demonstrated superior retention. However, the effects varied depending on the type of tooth movement.

Aligner trimline designs and extensions can significantly influence biomechanical performance and tooth movement efficacy in CAT. Straight extended trimlines generally demonstrate superior force delivery and retention, leading to more predictable clinical outcomes. This could reduce the need for revisions, thereby decreasing overall treatment time and increasing patient satisfaction. However, further research is needed to investigate the interactions between aligner trimline designs and other factors to develop evidence-based guidelines for their optimal combination in various clinical scenarios.

Gingival recession is a complication that can occur after orthodontic treatment, and its cause is still very controversial in the literature. The objective of this study was to report a clinical case of orthodontic retreatment conducted with in-office aligners and root coverage using free gingival graft, connective tissue graft, and Emdogaim for a patient with severe gingival recession.

This report presents a potential solution to correct a gingival recession with in-office clear aligner. A mandibular left lateral incisor whose root was positioned buccally to the bone plate, likely due to improper bonding of a fractured orthodontic retainer. The treatment consisted of 10 in-office aligners, which effectively repositioned the root within the alveolus. After the orthodontic retreatment, the patient underwent gingival grafting surgery, which was successful due to the accurate positioning of the root in the socket, influencing bone deposition in the area. Subsequent 4-year follow-up showed treatment stability, mainly in the soft tissue area.

Within the limitations of this case report, the in-office aligners facilitated individualized and precise movements, allowing for torque adjustments when necessary. Besides that, the improved root positioning facilitated successful surgical procedures for covering the gingival recession, including the free gingival graft (FGG) and connective tissue graft with Emdogain (CTG + Emdogain).

This case report presents an orthodontic treatment alternative for the multidisciplinary correction of a gingival recession, meeting the esthetic and functional demands of an adult patient.

To evaluate the accuracy of dental rotational movements using clear aligners with different attachment configurations.

This retrospective study analysed 212 teeth from 89 patients undergoing Invisalign treatment. Digital models were analysed after the virtual treatment plan (ST1) and after the first treatment phase (ET1) to evaluate the effective clinical rotational movement. The rotational movements of incisors, canines, and bicuspids were measured using data from the Clincheck Movements Table. ST1 and ET1 were compared to determine the actual rotational movement achieved (ST1-ET1). The presence or absence of attachments (rectangular or optimized) on teeth was analysed. The accuracy of rotational movements among attachment types was compared using the Kruskal-Wallis test. Multiple linear regressions were conducted with accuracy as the dependent variable and tooth type, gender, and age as predictors.

Optimized attachments had the highest median accuracy (70%), followed by rectangular (65%), and without attachment (63%), with no significant differences (p = .5). There were no significant differences across age groups, genders, or tooth types. Baseline accuracy was 68.62% (95% CI: 56.03-81.20, p < .001). Age was a significant predictor (estimate = -0.30, 95% CI: -0.58 - -0.03, p = .032), indicating decreased accuracy with increasing age. The model's R2 was 0.046, with an adjusted R2 of 0.003, indicating minimal variance explained.

The addition of attachment configurations to clear aligners improves rotational accuracy, but not significantly. Further advancements in these configurations are needed to enhance the performance of the aligners.

This study aimed to introduce a novel technique for fabricating provisional crowns integrated as a single unit with aligner attachments.

A total of 60 crowns with attachments were prepared: 20 conventional (Protemp) and 40 3D-printed (20 bonded with attachments; 20 integrated with composite attachments as a single unit) using NextDent resin. Two central incisors were scanned (once without attachments and once with attachments) to create STL files for specimen printing. Half of the specimens (30, n = 10 per group) underwent thermal cycling (5000 cycles). Shear bond strengths (MPa) were evaluated using a universal testing machine. The debonded areas and attachment failures were analyzed to determine the fracture type. Data analyses were performed using ANOVA and post hoc Tukey tests (α = 0.05).

The 3D-printed specimens showed higher strength values than the bonded attachments per group (P < 0.001). The 3D-printed crowns with attachments demonstrated the highest strength (12.39 ± 1.92 MPa). Thermal cycling significantly decreased the bond strength of the attachments (P < 0.001), except in the 3D-printed crowns with composite attachments as a single unit, which showed no significant change after thermal cycling (P = 0.643). In the bonded attachment groups, the adhesive type was the predominant failure mode, while in the 3D-printed groups, attachment fractures were the primary cause of failure.

The 3D-printed provisional crowns with attachments have high strength and is clinically appropriate for orthodontic treatment when temporization of teeth is indicated.

The developed technique for fabricating 3D-printed provisional restorations with orthodontics attachments as a single unit is a promising approach. The technique may be incorporated into the digital orthodontic treatment workflow when temporization is indicated.

Premature loss of first permanent molars is a common occurrence in clinical practice, leading to abnormal occlusion and inefficient mastication for patients. This case report presented the orthodontic retreatment of a 32-year-old female patient who suffered from premature loss of mandibular bilateral first molars. The mesial tipping of the mandibular second molars led to an occlusal interference, resulting in a clockwise rotation of the lower jaw and an anterior open bite (AOB). We achieved long-distance molar mesialization using clear aligners with Albert cantilever arms. After 42 months of treatment, the patient's occlusion and facial profile significantly improved. The cantilever combined with the cleat aligner treatment has been clinically effective for the protraction of mandibular posterior teeth, extending the field of application of clear aligners.

Data regarding the efficacy of deep overbite correction with clear aligner therapy in adolescent patients are lacking. This study aimed to investigate the efficacy of deep overbite reduction in adolescent patients treated with Invisalign (Align Technology, San Jose, Calif) aligners.

This retrospective study investigated a sample of 102 patients aged 10-17 years from a large database. All patients had completed wear of a prescribed series of Invisalign aligners with planned overbite reduction on a nonextraction basis. The predicted, pretreatment, and posttreatment overbite measurement values were obtained from Align Technology's ClinCheck digital facility. Linear modeling, with Bland-Altman plots, was used to compare the effect of age, the use of bite ramps, and the adoption of the eighth-generational (G8) protocol on the difference between predicted and achieved overbite measurements.

A total of 102 patients with a mean ± standard deviation age of 13.94 ± 1.53 years satisfied the selection criteria. A mean ± standard deviation of 41.38 ± 30.43% of the predicted overbite reduction was achieved. There were no differences in the predictability of overbite reduction between patients who were aged <14 years or those aged 14-17 years (P = 0.73), between patients prescribed and not prescribed bite ramps (P = 0.25), or between patients prescribed the G8 protocol and not prescribed the G8 protocol (P = 0.65).

The average achieved overbite was less than half of what was planned by the orthodontists via the ClinCheck facility. The age grouping, the provision of bite ramps, and the G8 protocol appear to have little influence on the efficacy of overbite reduction in adolescent patients.

This study aimed to investigate the effect of three-dimensional (3D) printed clear aligners (CA) with different designs on the extrusion of mandibular premolars using a force/moment measurement system and digital image correlation (DIC).

The forces and moments applied to the mandibular canines, first and second premolars were measured using a multi-axis force/moment transducer when an extrusion of 0.5 mm was planned, assuming the mandibular first premolars were intruded by 1 mm. In addition, displacement and strain changes in the CA were analyzed using the DIC method. CA designs were categorized based on the presence of first premolar attachment and subdivided into equigingival margins, 1-mm extended margins, equi-margins with 1-mm thickness and height, and equi-margins with 1-mm reduced buccolingual width. The CA was printed directly at a thickness of 0.5 mm, and the experiments were conducted at 37°C.

The results showed that attachment played an important role in the extrusion of first premolars in both the force/moment measurement system and the DIC method. Intrusion was observed without attachment, even though extrusion was planned. CA designs apply greater force to the cervical region by extending the margin or reducing the buccolingual width, thereby improving extrusion efficiency.

Force and moment changes in direct 3D printed CA are complex and difficult to predict; however, modifying aligner designs, such as extending the margin or reducing buccolingual width, and using appropriate attachments could minimize unwanted tooth movement, optimize planned treatment, and increase treatment predictability.

This study aimed to compare the predicted and achieved labiolingual inclinations of the maxillary central incisors in adult Class II division 2 malocclusions treated with clear aligners using Power Ridges® and composite attachments.

This retrospective study included 24 patients (mean age, 26.5 ± 3.3 years). The patients had Class II division 2 malocclusion and were treated with non-extraction with Invisalign® clear aligners with either Power Ridges® or composite attachments to enhance the predictability of required change in labiolingual inclination for the maxillary central incisors. Before treatment, treatment prediction and final digital models were exported as stereolithography files and superimposed using the eModel 9.0 "Compare" software. The predicted and achieved labiolingual incisor inclinations were compared.

The mean accuracies of the achieved inclination of the central incisors were 68.3% in the Power Ridges® group and 71.6% in the attachments group. No statistically significant differences in predictability were found between the groups (P > 0.05). A low positive correlation was observed between the predicted inclination change and the average absolute difference between the predicted and achieved inclinations (r = 0.19).

Predicted labiolingual inclination is not fully achieved with clear aligners in both the Power Ridges® and attachment groups. Clinicians must take measures to counteract this limitation, specifically in Class II division 2 cases.

This study aimed to evaluate the effects of molar attachment orientation and designed molar vertical movement on molar distalisation using clear aligners. Specifically, the study focused on the impact of vertical forces during upper second molar distalisation.

A three-dimensional finite element analysis was conducted to simulate upper molar distalisation using clear aligners. Four attachment orientations (0°, 45°, 90° and 135°) were designed. The study included three scenarios: distalisation alone; distalisation combined with intrusion; and distalisation combined with extrusion. The displacement tendencies and stress distribution on the second molar under various attachment orientations and vertical movements were analysed.

Molar distalisation resulted in buccal tipping, distal tipping and intrusion tendency in all models. The molar with 135° attachment orientation exhibited the most significant distal movement under intrusive force, while the one with 45° attachment showed the greatest distal movement under extrusive force. Additionally, greater distal movement was achieved with intrusive force compared to extrusive force, likely due to improved aligner grip on the attachments and teeth during intrusion.

Attachment orientation significantly affects the effectiveness of molar distalisation and vertical movement with clear aligners. The 90° attachment group achieved the most effective molar distalisation. The 135° attachment is more effective under intrusive force, while the 45° attachment is preferable under extrusive force.

This study compared the achieved tooth movement to that predicted in the preliminary simulated digital treatment plan between adults and teenagers.

Records of 60 patients (30 adults; mean age: 36.6 ± 11.36 years, and 30 teenagers; mean age: 16.23 ± 2.25 years) were randomly selected. Initial and predicted models were obtained from the initial simulated treatment plan. The first model of the refinement scan was labeled as achieved. SlicerCMF software (version 3.1; https://www.slicer.org ) was used to superimpose the achieved and predicted digital models over the initial ones with regional superimposition on relatively stable first molars. 600 teeth were measured in each group for horizontal, vertical, angular movements, and transverse dimensions. Accuracy was defined as the achieved amount of movement minus predicted and was calculated for each individual and compared between teens and adults.

The mandibular inter-canine width accuracy was statistically significant between groups (p = 0.050). Significant under-correction in horizontal movements was noted for mandibular first premolars in teenagers compared to adults (p = 0.037). There was considerable over-correction in horizontal movements for mandibular central and lateral incisors between groups (p < 0.05). No significant difference was observed between groups in the vertical plane. Rotations were underachieved for maxillary first premolars, more in adults than teenagers (p = 0.017).

The accuracy of achieved versus predicted tooth movement between adults and teenagers was significant for the inter-canine width. Mandibular central and lateral incisors showed significantly greater over-correction in adults in the horizontal plane. The accuracy of rotations and vertical movements was comparable.

Loss of the mandibular first molar is common in orthodontic patients. One treatment option is the mesialization of the second and third molars. This study aimed to investigate the displacement and type of movement in the second molar during mandibular second molar mesialization with clear aligner treatment using finite element analysis in configurations with or without pontic, semipontic, and anatomic pontic for the edentulous space.

Mesialization of the mandibular second molar with clear aligner treatment was simulated using the AlGOR Fempro program (ALGOR, Inc, Pa) with 3 different configurations.

In the transverse direction, the highest rotation occurred in the anatomic pontic model, whereas the lowest rotation was in the semipontic model. In the sagittal axis, although tooth movement was realized by tipping in all scenarios, the semipontic model showed the closest movement to translation because of a higher rate of crown-root movement. In the vertical axis, although extrusion occurred in all configurations, the semipontic model showed the least extrusion forces, whereas the anatomic pontic model showed the most.

Mesiobuccal rotation, mesial tipping, and extrusion were observed in all models. However, the semipontic design had the closest movement to translational. Further randomized, controlled clinical trials are needed to evaluate the effects of different pontic designs on tooth movements.

To evaluate the reliability of information produced by the artificial intelligence-based program ChatGPT in terms of accuracy and relevance, as assessed by orthodontists, dental students, and individuals seeking orthodontic treatment.

Frequently asked and curious questions in four basic areas related to orthodontics were prepared and asked in ChatGPT (Version 4.0), and answers were evaluated by three different groups (senior dental students, individuals seeking orthodontic treatment, orthodontists). Questions asked in these basic areas of orthodontics were about: clear aligners (CA), lingual orthodontics (LO), esthetic braces (EB), and temporomandibular disorders (TMD). The answers were evaluated by the Global Quality Scale (GQS) and Quality Criteria for Consumer Health Information (DISCERN) scale.

The total mean DISCERN score for answers on CA for students was 51.7 ± 9.38, for patients was 57.2 ± 10.73 and, for orthodontists was 47.4 ± 4.78 (P = .001). Comparison of GQS scores for LO among groups: students (3.53 ± 0.78), patients (4.40 ± 0.72), and orthodontists (3.63 ± 0.72) (P < .001). Intergroup comparison of ChatGPT evaluations about TMD was examined in terms of the DISCERN scale, with the highest value given in the patients group (57.83 ± 11.47) and lowest value in the orthodontist group (45.90 ± 11.84). When information quality evaluation about EB was examined, it GQS scores were >3 in all three groups (students: 3.50 ± 0.78; patients: 4.17 ± 0.87; orthodontists: 3.50 ± 0.82).

ChatGPT has significant potential in terms of usability for patient information and education in the field of orthodontics if it is developed and necessary updates are made.

Background: This study evaluated the number of aligners that Invisalign ClinCheck™ Pro Software estimates for correcting different malocclusion traits. Methods: This retrospective study included 157 non-extraction patients over the age of 12 years old with easy to mild malocclusions who were treated with Invisalign aligners. The Index of Complexity, Outcome, and Need (ICON) was used to evaluate the malocclusion complexity level. The number of aligners (upper, lower, and total) required to correct the malocclusion was compared based on sex, ICON level, molar and canine class, occlusal asymmetry, overbite, overjet, crowding, incisor inclination, and Bolton discrepancy. A Mann-Whitney U test (for comparisons between two groups) or a Kruskal-Wallis test (for comparisons between three or more groups) (p < 0.05) was used to evaluate differences in the number of aligners across variable categories. Results: ICON, molar class, overbite, and overjet presented significant differences (p < 0.05) in the number of aligners (upper, lower, and total) required to correct a malocclusion. Canine class and lower dental crowding showed significant differences in the lower and total number of aligners (p < 0.05). Conclusions: The number of aligners increases when the malocclusion presents any of the following elements: the absence of molar or canine class I, an altered overjet or overbite, severe lower crowding, or a higher complexity level. The clinician should consider these malocclusion traits when estimating the number of aligners needed for correction.

To evaluate the effects of varying direct attachment shape and size on the forces and moments generated by thermoplastic aligners during simulated expansion.

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.

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).

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.

This study aimed to investigate the biomechanical effects of clear aligner (CA) with different shape designs at extraction space (CAES) area during space closing.

A finite-element method (FEM) model of mandibular dentition, periodontal ligaments, attachments, and corresponding CA was established. The connecting rod design of CAES was modelled for the control group. Eight test groups with different heights of CAES from -4 mm to +4 mm were designed. Tooth displacement tendencies were calculated. The maximum principal stress in PDLs, teeth, and CAs was analysed. Both global coordinate system and local coordinate system were also used to evaluate individual tooth movements.

Across all groups, stresses concentrated on the lingual outer surface of CAESs. For the lowered CAES groups, both the stress value and the stress distribution area at CAESs were increased. The lowered CAES groups showed reduced movement in anterior teeth and less tipping tendency of the canines.

The shape of CAES has a biomechanical impact on anterior teeth movement and should be considered in aligner design. The results suggest that increasing the height of CAES can enhance anterior teeth retraction, while lowered CAES may facilitate controlled root movement. Changes in the shape of CAES represent a potential direction for biomechanical improvement of clear aligner in extraction cases and are worth exploring.

This case report aims to present how digital technology can be employed to plan the orthodontic movement of teeth into their final positions for prosthodontic rehabilitation. An interdisciplinary approach to treatment planning and the result of prosthodontic treatment involves the cooperation of an orthodontist and a prosthodontist. When planned to achieve optimal results for a minimally invasive and functional prosthodontic treatment, orthodontic pretreatment provides superior esthetic results and favorable long-term success.

The orthodontic movements of the teeth were planned so that the prosthodontist could reconstruct an optimally functional and esthetic occlusion while preserving the hard dental tissues. The orthodontic pretreatment minimized the need to prepare the teeth, avoiding any mucogingival surgery to improve the gingival architecture.

In complex clinical cases, it is essential to evaluate the advantages of an orthodontic pretreatment before starting a prosthodontic treatment. This pretreatment can help preserve dental tissues, reduce or eliminate the need for surgical intervention, and achieve long-term stability and esthetic results.

This case clearly shows the benefits of orthodontic pretreatment for prosthodontic outcomes. With modern digital tools, such an orthodontic pretreatment should become standard clinical practice when planning a complex clinical case.

Clear aligners are popular orthodontic tools because of their relatively aesthetic appearance and convenience of use. Nevertheless, bodily tooth movements still present challenges. This study evaluated various configurations of attachments placed on the mandibular canine in terms of the efficiency of canine bodily movement and correction of tipping.

A finite element model of the mandible was constructed to investigate the effects of various attachment configurations on the overall bodily movement and undesirable tipping of a mandibular canine. Canine movements were categorized into four types, namely tipping and bodily movements in the mesial and distal directions. The size and shape of the attachments were fixed, but their placement and orientation were varied. Five and seven attachment configurations were evaluated for their influence on tipping and bodily movements, respectively.

Attachment configuration significantly influenced mandibular canine tipping. The mesial occlusal-distal cervical and mesial occlusal-mesial cervical configurations had notable effects on mesial tipping, and the mesial occlusal-mesial cervical configuration excelled in distal tipping by increasing strain by 33.1%. The mesial occlusal-mesial cervical attachment configuration consistently had superior efficiency in facilitating both mesial and distal bodily movements of the canine.

The mesial occlusal-mesial cervical attachment configuration excelled in all four types of canine movement. Irrespective of the attachment configuration, canines tend to move overall with slight tipping due to skeletal resistance and their center of rotation. The attachment configuration is crucial to the success of clear aligner treatment and must be carefully considered in clinical practice.

To assess the effect of inter-proximal enamel reduction (IPR) on interradicular bone volume and incisal inclination in patients undergoing clear aligner therapy (CAT).

The study sample consisted of 60 cases which underwent orthodontic CAT, in a private clinic in Dammam, KSA. A total of 120 CBCT scans (60 pre-treatment and 60 post- treatment) were measured using the CS 3D Imaging software to examine bone volume (using height, width, and depth of the interproximal area) and incisal inclination. The corresponding ClinCheck models were collected to determine the amount and locations of interproximal reduction performed. Little's Irregularity Index values were measured using OrthoCAD software. Paired sample t-test was used to address the measurements of bone height, width, depth, bone volume, and inclination of upper and lower incisors before and after IPR.

IPR did not affect the upper or lower bone volume except at LR3-2 and UL 2 - 1 where a significant difference between the bone volume with and without IPR was detected (p = 0.02 and p = 0.04 respectively). Upper and lower incisor inclination showed a statistically significant decrease after IPR. There was no correlation between IPR and bone volume difference between upper and lower teeth except at LR3-2 and UL 2 - 1.

IPR had no significant effect on inter-radicular bone volume except at areas of lower right canine-lateral and at areas of upper left central-lateral. There was a positive correlation between the amount of IPR and incisal inclination.

The current study findings suggest that while IPR has a minimal and localized effect on bone volume in certain areas, it plays a role in adjusting incisal inclination, highlighting its significance in the careful planning of orthodontic treatment using clear aligners.

Passive non-destructive evaluation tools such as acoustic emission (AE) testing and acousto-ultrasonics (AU) approach present a complex problem in damage localisation in complex and nonhomogeneous geometries. A novel AU-guided AE frequency interpretation approach is proposed in this research work which aims at overcoming this limitation. For the experimental evaluation, the damage sources from a geometrically complex clear dental aligners are tested under cyclic compression load and their origins are evaluated. Despite the rapid worldwide diffusion of the clear aligners, their mechanical behaviour is poorly investigated. In this work, the frequency characteristics of the artificially simulated stress wave, generated from different dental positions of the clear aligners, are studied using the AU approach. These frequency characteristics are then used to analyse the AE signals generated by these aligners when subjected to cyclic compressive loading. In addition, the time domain characteristics of the AE signals are studied using their Time of Arrival (ToA). The Akaike Information Criterion (AIC) is used to estimate the ToA. These frequency and time domain characteristics of the AE signals are used to estimate the local damage origin in the clear dental aligners. This will help in identifying localised damage sources during the usage period of the aligners. Experimental results revealed significant damages in the left maxillary premolar and right maxillary third molar of the aligners.

Although clear aligner can be efficient and predictable in some tooth movements, mandibular molar protraction is the least predictable owing to biological and biomechanical limitations. This case report presents a 20-year-old female with poor prognosed left mandibular first molar (#36), deviated dental midline and mild crowding. After extraction of #36, clear aligners and an Albert cantilever were used for treatment. Through carefully designed dual mechanical system, we achieved uprighting and protraction of #37 within 27 months, with crown and root movements of 9.9mm and 12.1mm, respectively. The predictability of the crown and root movement was 107.6% and 84.6%. Coincident dental and facial midline, class I molar and canine relationship and good root parallelism were also achieved. Large-distance mandibular molar protraction can be achieved effectively with a combination of Albert cantilever arm and clear aligner.

Clear aligner therapy (CAT) has become a popular orthodontic treatment option for adolescent and adult patients for its aesthetic, patient's comfort, and convenient features. It involves a programmed and simulated virtual planning, tracking, and quantifying of tooth movement to target positions. Over the years, the therapeutic scope of CAT has increased dramatically to include a wider range of malocclusions with the aid of orthodontic auxiliaries as adjunctive biomechanics. This narrative review aims at summarizing and evaluating current practices, efficacy and predictability of sequential distalization protocol for maxillary molars in class II treatment using CAT.

A systematic search for this review included electronic literature databases of MEDLINE via Pubmed, Web of Science, ProQuest and Embase to include all available published articles including systematic reviews, books, cases reports, and narrative literature reviews.

Most published studies are retrospective examining small sample size. Current literature should be interpreted carefully as studies differ in their outcome measurement process and timing. Although reports show 2-3 mm of molar distalization is possible, a distinguish between bodily movement and molar tip back should be made. There is a discrepancy between computer-assisted predicted outcome and actual clinical outcome reported in literature.

Molar distalization using CAT is possible. However, randomised trials with large sample size are necessary to draw more definitive conclusion about its efficacy and predictability. Due to the discrepancy between computer-assisted predicted outcome and actual clinical outcome, case refinement and possible altered treatment duration should be discussed with the patient in the planning stage. Since the process of molar distalization using CAT involves undesirable reaction force, it is essential to reinforce anchorage with suitable auxiliaries like composite attachments, class II/III elastics, and TADs.

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.

To compare the anterior crowding correction after sequential use of the first 5 aligners between two aligner exchange protocols (7 and 14 days) in mature adult patients.

Thirty-six patients over 35 years who received orthodontic treatment with Invisalign® were randomly allocated to two different aligner replacement sequence protocols: Group 1: exchange every 7 days (n = 18); and Group 2: exchange every 14 days (n = 18). All patients were scanned with iTero Element 5D® (Align Technology) in two treatment times: at pre-treatment (T1) and after using the first five aligners (T2). Little's Irregularity Index (LII) and arch widths were evaluated with OrthoCAD software. Intra and intergroup comparisons were performed with the dependent and independent t-tests. The results were considered significant for P < .05.

Thirty-five patients completed the study. Both groups' maxillary and mandibular Irregularity Indexesi were significantly lower at T2. There was no significant difference in inter-canine, inter-premolar, and intermolar distances. G2 (14 days) presented a greater decrease in mandibular irregularity than G1 (7 days).

Both exchange protocols (7 and 14 days) effectively correct anterior crowding in the initial phase of orthodontic treatment with aligners in mature adult patients. However, the 14-day exchange protocol provided a greater correction in mandibular anterior crowding in the evaluated period than the 7-day exchange protocol.

Aim Rotation of the mandibular premolars during aligner treatment is a difficult movement to achieve accurately. The purpose of this study is to compare the effects of different attachment types and positions used in clear aligner treatments on the rotation movement and retention of clear aligners in the rotated first premolar teeth. The study also addressed the stress values in periodontal ligaments (PDLs) with finite element analysis. Materials and methods For purposes of this research, we created a mandibular tooth model and modeled the premolar tooth with a 30° rotation. Twelve separate groups were created by attaching horizontal rectangular, vertical rectangular, ellipsoid, and semi-ellipsoid attachments to the premolar tooth in buccal, lingual, and combined buccal and lingual ways. A model without attachments was created to be used as the control group. An activation movement of 0.25 mm was applied to the first premolar tooth in all 12 models. The study evaluated clear aligner displacement, von Misses stress on the PDL, and tooth displacements using the finite element stress analysis method. Results It was found that the group with horizontal rectangular attachments placed on both the buccal and lingual sides had the highest stress value in the PDL (0.1971 MPa) and the highest displacement in the tooth (0.1267 mm). Conversely, the group with semi-ellipsoid attachments placed both buccally and lingually had the least displacement movement in clear aligners (0.1441 mm). Conclusion The results indicate that groups with attachments provided better retention than groups without attachments. Models with horizontal, rectangular attachments showed significantly more tooth displacement compared to other models. Horizontal rectangular attachments placed buccally and lingually combined to provide tooth movement in rotated mandibular first premolars can be recommended for clinical use.

The aim of this study is to evaluate the effect of different surface treatments on the shear bond strength (SBS) of clear aligner attachments bonded to Bis-acryl provisional crowns.

120 cylindrical bisacrylic composite material (ProTemp type) specimens were prepared and divided into six groups (n = 20) based on surface treatment, control: (no treatment); super coarse grit diamond bur, carbide bur, alumina-blasting, non-thermal plasma treatment, and Er:YAG laser treatment. The features of treated surfaces were examined using scanning electron microscopy (SEM). A flowable composite resin (Transbond XT; 3M Unitek) was bonded to the specimens forming the attachment. Half of specimens were subjected to thermal cycling (5,000 cycles). SBS was measured before and after thermal cycling. Each specimen was loaded at the attachment/resin interface at a speed of 0.5 mm/min until failure. The nature of the failure was analyzed using the composite remnants index (CRI). Two-way ANOVA and Tukey HSD were used for data analysis α =  0.5. For CRI scores analysis, Kruskal-Wallis test and Dunn's multiple comparison were used as post-hoc test.

SEM analysis showed that all surface treatments altered surface properties and increase surface bonding area. The specimens treated with plasma, Er:YAG laser, and alumina-blasting had higher SBS values before and after thermal cycling. In comparison to control plasma, Er:YAG laser, and alumina-blasting showed a significant increase in SBS (P < 0.001) while carbide and diamond bur groups showed no significant differences (P > 0.05). Thermal cycling significantly decreased the SBS of control, carbide bur, diamond bur, and Er:YAG laser while no significant effect of alumina-blasting and plasma group. Er:YAG laser and plasma groups significantly exhibited more dominance for scores 2 and score 3 and the absence of score 0.

Alumina-blasting, Er:YAG laser, or non-thermal plasma surface treatments increased the shear bond strength between clear aligner attachments and resin-based restorations.

Objectives: The purpose of this preliminary study was to determine the differences between planned and actual maxillary molar movements after the completion of treatment with an initial set of clear aligners including sequential maxillary molar distalization. Methods: The data records of 14 non-growing patients who completed orthodontic treatment with sequential maxillary molar distalization using clear aligners were retrospectively evaluated (n= 14, 4 males and 10 females, 33.61 ± 8.57 years). Data on planned tooth movements were obtained from ClinCheck software (ClinCheck Pro version 5.3). The amounts of actual tooth movements were obtained by performing superimposition of lateral cephalograms taken before and after treatment. The amounts of distal translation and tipping between planned and actual maxillary molar movements were compared with the paired Student's t-test. Results: The statistically significant differences between planned and actual translation movements of maxillary first and second molars were shown after completing treatment with the first series of aligners (p < 0.05). The average actual amount of molar distalization on maxillary first molars was less than the planned amount by 1.32 ± 0.42 mm. Similarly, the average actual amount of molar distalization on maxillary second molars was less than the planned amount by 1.57 ± 0.45 mm. The accuracy for molar distalization, namely, the percentage of actual distal translation to planned movement, was 40.11% for maxillary first molars and 35.39% for maxillary second molars. However, the difference between the planned and actual angulation movements was not significant (p > 0.05). Conslusions: In conclusion, the amounts of actual distal translation of maxillary molars through the utilization of clear aligners were significantly lower than planned. However, there were no statistically significant differences between the degrees of actual and planned molar angulation movement.

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.

This study aimed to evaluate the effects of varying auxiliaries on tooth movement and stress distribution when maxillary central incisors were torqued 1° with a clear aligner through finite element analysis.

Three-dimensional finite element models, including maxillary alveolar bone, periodontal ligament, dentition, and clear aligner, were constructed. According to the auxiliaries designed on the maxillary central incisor, 5 models were created: (1) without auxiliaries (control model), (2) with the power ridge, (3) with the semi-ellipsoid attachment, (4) with the horizontal rectangular attachment, and (5) with the horizontal cylinder attachment. The tooth movement and periodontal ligament stress distribution after a palatal root torque of 1° were analyzed for each of the 5 models.

With 1° torque predicted, the maxillary central incisor without auxiliaries showed a tendency of labial tipping, mesial tipping, and intrusion. The rotation center moved occlusally in the power ridge model. The labiolingual inclination variation increased in the semi-ellipsoid attachment model but decreased in the power ridge model. The maxillary central incisor is twisted in the distal direction in the power ridge model. The maxillary central incisor of the horizontal rectangular attachment and the horizontal cylinder attachment model behaved similarly to the control model. Periodontal stresses were concentrated in the cervical and apical areas. The maximum von Mises stresses were 11.6, 12.4, 3.81, 1.14, and 11.0 kPa in the 5 models. The semi-ellipsoid attachment model exhibited a more uniform stress distribution than the other models.

Semi-ellipsoid attachment performed better efficacy on labiolingual inclination, and power ridge performed better efficacy on root control. However, a distal twist of maxillary incisors could be generated by the power ridge.

Orthodontic appliances can influence the oral environment, including salivary pH levels, which play a crucial role in maintaining oral health. Understanding how different orthodontic appliances affect salivary pH levels can help in improving treatment outcomes and minimizing potential side effects.

In this in vitro study, we evaluated the effects of various orthodontic appliances on salivary pH levels using a simulated oral environment. Four different types of orthodontic appliances were tested: traditional metal braces, ceramic braces, lingual braces, and clear aligners. Saliva samples were collected and subjected to pH measurements using a standardized method. The pH measurements were recorded at three different time intervals: immediately after appliance placement, after 24 hours, and after 48 hours.

The initial pH values varied among the different orthodontic appliances: metal braces (pH 7.2), ceramic braces (pH 7.4), lingual braces (pH 7.1), and clear aligners (pH 7.5). After 24 hours, there was a decrease in pH levels for all groups: metal braces (pH 6.8), ceramic braces (pH 7.0), lingual braces (pH 6.7), and clear aligners (pH 7.2). After 48 hours, the pH levels continued to decrease: metal braces (pH 6.5), ceramic braces (pH 6.8), lingual braces (pH 6.4), and clear aligners (pH 6.9).

Our findings suggest that different orthodontic appliances have varying effects on salivary pH levels. Metal braces and lingual braces tend to cause a more pronounced decrease in salivary pH compared to ceramic braces and clear aligners. Monitoring salivary pH levels during orthodontic treatment may be beneficial in identifying potential risks to oral health and implementing appropriate interventions.

The purpose of this retrospective study was to evaluate the long-term results of orthodontic treatment with traditional braces and Invisalign, with a particular emphasis on treatment length, patient satisfaction, correction of malocclusion, and long-term stability.

Between 2020 and 2022, individuals who had orthodontic treatment at a tertiary care center had their data analysed. Patients with mild to severe malocclusions treated with conventional braces or Invisalign between the ages of 12 and 18 met the inclusion criteria. Assessments were done on results, length of treatment, degree of malocclusion, and long-term stability. With significance set at P < 0.05, statistical analyses comprised t-tests for treatment duration and Chi-square testing for malocclusion correction.

The mean treatment time for Invisalign was much shorter (18 months) than for conventional braces (24 months) (P < 0.001). With 88-90% success rates, both techniques demonstrated remarkable success rates in malocclusion treatment. Even though Invisalign was associated with a somewhat greater percentage of relapse instances, the difference was not statistically significant (P > 0.05).

In conclusion, Invisalign showed a much shorter treatment period than conventional braces, yet both showed excellent malocclusion correction. The choice of modality should be based on patient satisfaction, treatment objectives, and case complexity, taking into account the trade-offs between treatment length and potential variations in long-term stability.

This study explored the layperson's perception of comfort, satisfaction, and willingness to use various accessories in clear aligner therapy.

A total of 267 people analyzed standardized intraoral photographs of a female model in orthodontic treatment using: 1) only clear aligner (CA), the control group; 2) clear aligner+attachments (AT); 3) clear aligners+Cl II elastics (EL); 4) clear aligner+hybrid treatment with esthetic braces (HEB); 5) Clear aligner+hybrid treatment with metallic braces (HMB); 6) clear aligner+mini-implants (MI); 7) clear aligner+mini-implants and elastics for intrusion (MIE). In addition, a social media questionnaire was distributed to assess the willingness to undergo orthodontic treatment with various accessories.

There was a significant difference between CA and all the other groups (P<0.001), with CA being considered more comfortable and providing greater satisfaction compared to other accessories. Moreover, AT showed a significant difference in reducing treatment time compared to other groups.

The CA was the most comfortable, exhibiting a higher satisfaction rate and a greater willingness to use it. The AT therapy was perceived as more comfortable and was associated with higher satisfaction and a greater likelihood of use, especially if it resulted in reduced treatment time. On the other hand, the participants reported that the HMB, MI, and MIE accessories were less comfortable.

Background/Objectives: Machine learning (ML) models predicting the risk of refinement (i.e., a subsequent course of treatment being necessary) in clear aligner therapy (CAT) were developed and evaluated. Methods: An anonymized sample of 9942 CAT patients (70.6% females, 29.4% males, age range 18-64 years, median 30.5 years), as provided by DrSmile, a large European CAT provider based in Berlin, Germany, was used. Three different ML methods were employed: (1) logistic regression with L1 regularization, (2) extreme gradient boosting (XGBoost), and (3) support vector classification with a radial basis function kernel. In total, 74 factors were selected as predictors for these methods and are consistent with clinical reasoning. Results: On a held-out test set with a true-positive rate of 0.58, the logistic regression model has an area under the ROC curve (AUC) of 0.67, an average precision (AP) of 0.73, and Brier loss of 0.22; the XGBoost model has an AUC of 0.67, an AP of 0.74, and Brier loss of 0.22; and the support vector model has a recall of 0.61 and a precision of 0.64. The logistic regression and XGBoost models identify predictors influencing refinement risk, including patient compliance, interproximal enamel reduction (IPR) and certain planned tooth movements, for example, lingual translation of maxillary incisors being associated with the lowest risk of refinement and rotation of mandibular incisors with the highest risk. Conclusions: These findings suggest moderate, well-calibrated predictive accuracy with both regularized logistic regression and XGBoost and underscore the influence the identified factors have on the risk of refinement in CAT, emphasizing their importance in the careful planning of orthodontic treatment and the potential for shorter treatment times, less patient discomfort, and fewer clinic visits. Identification of at-risk individuals could support tailored clinical decision-making and enable targeted interventions.

(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.

Clear aligner treatment (CAT) has been evolving over the past two decades. This study aims to conduct a comprehensive and up-to-date bibliometric analysis of publications related to CAT, presenting the research trends, landscapes, and hot spots in this field. All publications were retrieved from the Web of Science Core Collection from 2003 to 2023. In addition to a general analysis of research landscapes, the following items were analyzed, i.e., countries, institutions, authors, journals, publications, and keywords. A total of 1031 relevant publications were included in this study. From 2003 to the present, the number of publications and citations in this field showed an increasing trend. Italy led in terms of publication counts, and Sichuan University in China had the highest publication counts among institutions. In total, 33 scholars had published a minimum of 10 articles, and the collaborations among them were mostly within each country. The American Journal of Orthodontics and Dentofacial Orthopedics published the most relevant publications. "Predictability of tooth movements," "influencing factors for clinical efficacy," "biomechanics," and "patients' perception and periodontal health" stood out as the core research focus on CAT. Our study identified the most influential countries, institutions and authors, and their cooperative relationships, and detected hot research topics on CAT, calling for more high-quality international collaborative research in the future.