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The article in the Laryngoscope journal discusses the use of a pre-epiglottic baton plate as a non-invasive treatment for newborns with Pierre Robin Sequence, a condition that can lead to upper airway obstruction. The study outlines the practical workflow and steps involved in customizing and using the baton plate to relieve airway obstruction, facilitate feeding, and support mandibular growth. The case example presented in the article demonstrates successful treatment without the need for surgical intervention, highlighting the potential efficacy of this non-invasive approach for managing PRS in newborns. [Extracted from the article]

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Current standardized in vitro bending experiments for orthodontic archwires cannot capture friction conditions and load sequencing during multi-bracket treatment. This means that clinically relevant forces exerted by superelastic wires cannot be predicted. To address these limitations, this study explored a novel test protocol that estimates clinical load range. The correction of a labially displaced maxillary incisor was simulated using an in vitro model with three lingual brackets. Deflection force levels derived from four different protocols were designed to explore the impact of friction and wire load history. These force levels were compared in nickel-titanium (NiTi) archwires with three commonly used diameters. The unloading path varied between protocols, with single or multiple sequences and different load orders and initial conditions. Deflection forces from the new protocol, employing multiple continuous load/unload cycles (CC incr), consistently exceeded those from the conventional protocol using a single continuous unloading path (CU decr). Mean differences in plateau force ranged from 0.54 N (Ø 0.014" wire) to 1.19 N (Ø 0.016" wire). The CC inr protocol also provided average force range estimates of 0.47 N (Ø 0.012" wire), 0.89 N (Ø 0.014" wire), and 1.15 N (Ø 0.016" wire). Clinical orientation towards CU decr carries a high risk of excessive therapeutic forces because clinical loading situations caused by friction and load history are underestimated. Physiological tooth mobility using NiTi wires contributes decisively to the therapeutic load situation. Therefore, only short unloading sequences starting from the maximum deflection in the load history, as in CC incr , are clinically meaningful. • Friction and load history affect deflection forces of orthodontic NiTi wires. • Conventional in vitro 3-bracket bending tests underestimate clinical force levels. • Physiological tooth movement must be considered to derive clinically relevant loads. • Reactive forces from wire deflection may vary because of physiological conditions. • Sequential short unloading sequences allow characterization of clinical load range. [ABSTRACT FROM AUTHOR]

Objective: To evaluate tooth displacement and periodontal stress generated by the dual action vertical intra-arch technique (DAVIT) for open-bite correction using three-dimensional finite element analysis. Methods: A three-dimensional model of the maxilla was created by modeling the cortical bone, cancellous bone, periodontal ligament, and teeth from the second molar to the central incisor of a hemiarch. All orthodontic devices were designed using specific software to reproduce their morpho-dimensional characteristics, and their physical properties were determined using Young's modulus and Poisson's coefficient of each material. A linear static simulation was performed to analyze the tooth displacements (mm) and maximum stresses (Mpa) induced in the periodontal ligament by the posterior intrusion and anterior extrusion forces generated by the DAVIT. Results: The first and second molars showed the greatest intrusion, whereas the canines and lateral incisors showed the greatest extrusion displacement. A neutral zone of displacement corresponding to the fulcrum of occlusal plane rotation was observed in the premolar region. Buccal tipping of the molars and lingual tipping of the anterior teeth occurred with intrusion and extrusion, respectively. Posterior intrusion generated compressive stress at the apex of the buccal roots and furcation of the molars, while anterior extrusion generated tensile stress at the apex and apical third of the palatal root surface of the incisors and canines. Conclusions: DAVIT mechanics produced a set of beneficial effects for open-bite correction, including molar intrusion, extrusion and palatal tipping of the anterior teeth, and occlusal plane rotation with posterior teeth uprighting. [ABSTRACT FROM AUTHOR]

Ectopic eruption of molars occurs more frequently in developing permanent dentition, and requires immediate intervention. Herein, two cases are discussed with ectopic eruption of permanent maxillary first molars which were diagnosed and managed conservatively using a modified Humphrey's appliance, named the NR's appliance. The appliance was fabricated by band adaptation and using wire components of a 21-gauge stainless-steel wire. Also, the Nance palatal arch was used as the anchorage unit. The molars were uprighted and distalized within 3 months. Early diagnosis and prompt treatment could result in prevention of malocclusion in the early mixed dentition period. [ABSTRACT FROM AUTHOR]

Objective: The aim of this case series was to test various personalized, CAD/CAM-manufactured orthodontic extrusion appliances. The appliances were characterized by high rigidity and manufacturing precision. In addition, the orthodontic force vector could be precisely and three-dimensionally planned. Method and materials: After a comprehensive diagnosis of three patients with deep fractured teeth by an interdisciplinary team, each patient's personalized extrusion protocol was determined (slow or rapid extrusion). Based on an intraoral scan, the personalized extrusion appliances were then digitally planned and manufactured using selective laser melting. The force vector was also precisely planned during this process. The appliances were inserted, and the force on the teeth to be extruded was precisely applied in accordance with the extrusion protocol. After extrusion, the teeth were retained and, if necessary, permanently restored. Results: The target teeth of all three patients were successfully extruded. Furthermore, good cleanability and high wearing comfort of the appliances were maintained throughout treatment, as was the precise application of force. Conclusion: The effectiveness of the tested digital workflow for precise and simplified orthodontic extrusion was clinically proven. The workflow guaranteed the following throughout treatment: precise planning and application of the force system; improved periodontal hygiene; and improved wearing comfort of the appliance, without affecting the patient's existing occlusion. [ABSTRACT FROM AUTHOR]

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ABSTRACT Objective: This cross-sectional study evaluated the bone thickness on mini-implants insertion site, the factors that influence the digital planning of MARPE appliance (miniscrew-assisted rapid palatal expansion), and its different designs. Methods: A total of 135 plannings were assessed regarding the size of the expander screw used, the positioning and the type of the mini-implant rings, and their location in relation to the teeth. Bone thickness measurements were assessed in the region of the mini-implants’ trajectory. Differences between the sexes was verified using the ANOVA test (5% significance). Results: 73 cases were planned with 4 mini-implants and 62 cases, with 6 mini-implants. In 90% of cases, teeth #16 and #26 were used as supports, and the most used expander screw was 13mm (64.1% of cases). The anterior mini-implants of conventional MARPE showed more pronounced insertion in bone in males (5.9 ± 2mm; p= 0.025). The extra mini-implants (anterior region) were inserted with greater bone thickness in males (11.1 ± 2.3mm) compared to females (9.9 ± 1.8mm; p=0.041). A greater bone thickness was observed in males (10.1 ± 2.1 mm) when using mini-implants in the paramedian region. Conclusion: Additional rings allow more pronounced bone insertion. Male patients had greater bone thickness, which may be related to greater difficulty in opening the sutures. The alveolar process region seems to be a satisfactory site for mini-implants to those patients with reduced bone thickness in the paramedian posterior region. MARPE appliance must be customized for each patient, due to bone thickness and anatomical variations.

Ectopic eruption of molars occurs more frequently in developing permanent dentition, and requires immediate intervention. Herein, two cases are discussed with ectopic eruption of permanent maxillary first molars which were diagnosed and managed conservatively using a modified Humphrey's appliance, named the NR’s appliance. The appliance was fabricated by band adaptation and using wire components of a 21-gauge stainless-steel wire. Also, the Nance palatal arch was used as the anchorage unit. The molars were uprighted and distalized within 3 months. Early diagnosis and prompt treatment could result in prevention of malocclusion in the early mixed dentition period.

ABSTRACT Objective: This study aimed to compare the influence of four different maxillary removable orthodontic retainers on speech. Material and Methods: Eligibility criteria for sample selection were: 20-40-year subjects with acceptable occlusion, native speakers of Portuguese. The volunteers (n=21) were divided in four groups randomized with a 1:1:1:1 allocation ratio. The four groups used, in random order, the four types of retainers full-time for 21 days each, with a washout period of 7-days. The removable maxillary retainers were: conventional wraparound, wraparound with an anterior hole, U-shaped wraparound, and thermoplastic retainer. Three volunteers were excluded. The final sample comprised 18 subjects (11 male; 7 female) with mean age of 27.08 years (SD=4.65). The speech evaluation was performed in vocal excerpts recordings made before, immediately after, and 21 days after the installation of each retainer, with auditory-perceptual and acoustic analysis of formant frequencies F1 and F2 of the vowels. Repeated measures ANOVA and Friedman with Tukey tests were used for statistical comparison. Results: Speech changes increased immediately after conventional wraparound and thermoplastic retainer installation, and reduced after 21 days, but not to normal levels. However, this increase was statistically significant only for the wraparound with anterior hole and the thermoplastic retainer. Formant frequencies of vowels were altered at initial time, and the changes remained in conventional, U-shaped and thermoplastic appliances after three weeks. Conclusions: The thermoplastic retainer was more harmful to the speech than wraparound appliances. The conventional and U-shaped retainers interfered less in speech. The three-week period was not sufficient for speech adaptation.

Retrognathic mandible is the most common feature in growing children with skeletal Class II malocclusion. This does not self-correct with growth. Functional appliances are known to exert beneficial effects to improve this skeletal pattern. Among several removable functional appliances, Twin Block is the most preferred. Twin Blocks are designed for full-time wear such that maximum benefit from functional forces can be obtained. The maxillary and mandibular bite blocks occlude at a 70° angle on complete closure. It is important to angulate the inclines at exactly 70°, as an increase in this angulation will require a conscious effort from the patient. Incline Correct is designed to accurately measure and construct inclines at 70° to the occlusal plane. [ABSTRACT FROM AUTHOR]

Objective: Some modifications of orthodontic appliances such as the rapid maxillary expansion (RME) device with a Hyrax screw or Herbst are fabricated using traditional investment casting (lost-wax casting). This is precise but very labor-intensive. New technologies enable us today to use direct selective laser sintering (SLS) to produce freeform metallic structures. These machines are very expensive and only available in specialized laboratories. The aim of this investigation was to combine fused filament fabrication (FFF) 3D printing with wax-based filaments to produce orthodontic appliances via investment casting. Method and materials: For demonstration purposes, a lingual arch, a palatal arch, and an RME appliance were digitally designed based on an intraoral scan. The *.stl files were sliced and printed with a dual-nozzle FFF printer. The object was printed with a wax-based filament especially suited for investment casting, and support structures were printed with water-soluble polyvinyl-alcohol (PVA) filament. The printed objects were cast in metal and finished. Results: All appliances were successfully cast and polished. They were provisionally placed intraorally. The fit was clinically very good and comparable to traditionally crafted appliances. The printing and handling of the parts made of these special filaments is challenging. Conclusion: With this experiment, the successful production of investment casting using FFF printing was shown for the first time. [ABSTRACT FROM AUTHOR]

Copyright of Clinical Orthodontics is the property of Dental Press International and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Clinical Orthodontics is the property of Dental Press International and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: Infrazygomatic crestal (IZC) implants have gained increased popularity over the past few years. Hardly any studies have been done to assess the rate and reasons for failure of IZCs. This prospective study was planned and designed with the primary objective of assessing the rate of failure of bone-screws (BS) placed in the infrazygomatic crest. In continuation, the secondary objective was to assess the factors that were associated with the failure. Materials and methods: The study was carried out by taking a detailed case history, (age, gender, vertical skeletal pattern, medical history), photographic records, radiographs, and clinical examination of a total of 32 randomly selected. patients of south indian origin who required infrazygomatic implants bilaterally as the choice of anchorage conservation to retract their incisors. All selected subjects were required to take a PA Cephalogram after the implant placement. The age of the patients ranged from 18 to 33 with an average age of 25 years. The patient log was maintained which included the treatment mechanics, status of oral hygiene, stability of implants, time of loading of the implant, presence of inflammation and time of failure of implant. The angulation of implant was measured on a digital PA cephalogram using Nemoceph software. These parameters were examined to evaluate independent and dependent variables using the Chi-Square test and Fischer's exact test. Result: A failure rate 28.1% for IZC placed in the infrazygomatic crest region was observed. Patients with a high mandibular plane angle, poor oral hygiene, immediately loaded implant, peri-implantitis, and severe clinical mobility showed higher failure rates. Variables such as age, gender, sagittal skeletal pattern, length of the implant, type of movement, occluso-gingival position, method of force application, and angle of placement were not significantly associated with implant failure. Conclusion: Oral hygiene and peri-screw inflammation must be controlled to minimize the failure of bone screws placed in the infrazygomatic crest region. Loading of the implant should be done after a latent period of two weeks. A higher failure rate was observed in patients with vertical growth pattern.

Purpose: The aim of this study was to evaluate how continuous heavy orthopedic forces affect the stability of sandblasted, large-grit, acid-etched (SLA)–surfaced miniscrew implants and surrounding bone tissue healing at three different loading periods with treatment of photobiomodulation and ozone therapy. Materials and Methods: Miniscrew implants were applied on the tibias of 9-month-old rabbits (n = 18). The animals were randomly divided into three groups: control, photobiomodulation, and ozone therapy. In all groups, miniscrew implants were loaded with 500 gf at 0, 4, and 8 weeks, respectively (G1, G2, and G3). Several biomechanical and histologic analyses were performed in different centers to measure the implant stability quotient level, bone volume, and bone-to-implant contact. Results: According to the results of the Infinite Focus Microscopy, the ozone therapy group revealed significantly higher scores than the control group and photobiomodulation group at the 4-week loading time, whereas the photobiomodulation and ozone therapy groups revealed significantly higher scores than the control group at the 8-week loading time in terms of bone volume measurements in mm3 (P < .05). According to the histologic analysis, the ozone therapy and photobiomodulation groups revealed significantly higher scores than the control group at the 4-week loading time, whereas the photobiomodulation group showed the highest scores among the 8-week loading groups (P < .05). Conclusion: This is the first study in the literature that reveals a better osseointegration process in miniscrew implants when treated with photobiomodulation and ozone therapy compared with control groups. Although the photobiomodulation and ozone therapy groups did not reveal significantly higher scores in immediately loaded miniscrew implants (G1), these treatments were significantly more effective when loaded after 4 or 8 weeks of osseointegration (G2 and G3). SLA-surfaced miniscrew implants are successful in the orthopedic forces (500 gf) and can be removed without complications. [ABSTRACT FROM AUTHOR]

Nowadays, many people use clear aligners to address their dental issues. The efficacy of transparent dental aligners must be investigated even though they are more aesthetically pleasing, easy to use, and tidy than permanent tools. Thirty-five patients in this study's sample group who used Nuvola® clear aligners for their orthodontic therapy were prospectively observed. Initial, simulated, and final digital scans were analysed with a digital calliper. The actual results were compared with the prescribed ending position to evaluate the efficacy of transversal dentoalveolar expansion. Aligner treatments in Groups A (12) and B (24), particularly in the dental tip measures, demonstrated high adherence to the prescription. On the other hand, the gingival measures exhibited a greater level of bias, and the differences were statistically significant. However, there was no difference in the outcomes between the two groups (12 vs. 24). Within specific parameters, the evaluated aligners were shown to be helpful in predicting movements in the transverse plane, particularly when considering movements linked to the vestibular–palatal inclination of the dental elements. This article compares the expansion effectiveness of Nuvola® aligners compared with other work in the literature using competitor companies. [ABSTRACT FROM AUTHOR]

Infrazygomatic crestal (IZC) implants have gained increased popularity over the past few years. Hardly any studies have been done to assess the rate and reasons for failure of IZCs. This prospective study was planned and designed with the primary objective of assessing the rate of failure of bone-screws (BS) placed in the infrazygomatic crest. In continuation, the secondary objective was to assess the factors that were associated with the failure. The study was carried out by taking a detailed case history, (age, gender, vertical skeletal pattern, medical history), photographic records, radiographs, and clinical examination of a total of 32 randomly selected. patients of south indian origin who required infrazygomatic implants bilaterally as the choice of anchorage conservation to retract their incisors. All selected subjects were required to take a PA Cephalogram after the implant placement. The age of the patients ranged from 18 to 33 with an average age of 25 years. The patient log was maintained which included the treatment mechanics, status of oral hygiene, stability of implants, time of loading of the implant, presence of inflammation and time of failure of implant. The angulation of implant was measured on a digital PA cephalogram using Nemoceph software. These parameters were examined to evaluate independent and dependent variables using the Chi-Square test and Fischer's exact test. A failure rate 28.1% for IZC placed in the infrazygomatic crest region was observed. Patients with a high mandibular plane angle, poor oral hygiene, immediately loaded implant, peri-implantitis, and severe clinical mobility showed higher failure rates. Variables such as age, gender, sagittal skeletal pattern, length of the implant, type of movement, occluso-gingival position, method of force application, and angle of placement were not significantly associated with implant failure. Oral hygiene and peri-screw inflammation must be controlled to minimize the failure of bone screws placed in the infrazygomatic crest region. Loading of the implant should be done after a latent period of two weeks. A higher failure rate was observed in patients with vertical growth pattern. [Display omitted] • Bone screws can be positioned in movable mucosa without risking failure. • Loading bone screws after a period of two weeks had higher scope for success. • Bone screw failure is highly influenced by poor oral hygiene & peri-implantitis. • Individuals with vertical growth show an increased risk of failure of bone screws. • Minimal bone screw mobility is acceptable if it can withstand orthodontic loading. [ABSTRACT FROM AUTHOR]

BackgroundMiniscrew-assisted rapid palatal expansion (MARPE) has been adopted in recent years to expand the maxilla in late adolescence and adult patients. Maxillary Skeletal Expander (MSE) is a device that exploits the principles of skeletal anchorage to transmit the expansion force directly to the maxillary bony structures and is characterized by the miniscrews' engagement of the palatal and nasal cortical bone layers. In the literature, it has been reported that the zygomatic buttress is a major constraint that hampers the lateral movement of maxilla, since maxilla is located medially to the zygomatic arches. The objective of the present study is to analyze the changes in the zygomatic bone, maxillary bone, and zygomatic arches and to localize the center of rotation for the zygomaticomaxillary complex in the horizontal plane after treatment with MSE, using high-resolution cone-beam computed tomography (CBCT) images.MethodsFifteen subjects with a mean age of 17.2 (± 4.2) years were treated with MSE. CBCT records were taken before and after miniscrew-assisted maxillary expansion; three linear and four angular parameters were identified in the axial zygomatic section (AZS) and were compared from pre-treatment to post-treatment using the Wilcoxon signed rank test.ResultsAnterior inter-maxillary distance increased by 2.8 mm, posterior inter-zygomatic distance by 2.4 mm, angle of the zygomatic process of the temporal bone by 1.7° and 2.1° (right and left side) (P  0.05).ConclusionsIn the horizontal plane, the maxillary and zygomatic bones and the whole zygomatic arch were significantly displaced in a lateral direction after treatment with MSE. The center of rotation for the zygomaticomaxillary complex was located near the proximal portion of the zygomatic process of the temporal bone, more posteriorly and more laterally than what has been reported in the literature for tooth-borne expanders. Bone bending takes place in the zygomatic process of the temporal bone during miniscrew-supported maxillary expansion.

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Introduction: There is currently no recommendation for retaining corrected bimaxillary proclination cases. This study aimed to compare retention protocols for maintaining stability of such cases., Materials and Methods: In this single-center, single-blinded parallel control trial, 27 participants were assigned to three groups using block randomization with a 1:1:1 allocation ratio; fixed bonded retention (FBR), vacuum-formed retention (VFR), and dual retention (DR) comprising both types. Data were collected every 3-months from debond (T0) for 12 months (T4). The primary outcomes measured changes in soft and dental tissue parameters on traced lateral cephalograms. Secondary outcomes included intra-arch changes and the oral health impact profile (OHIP-14[M]). This trial was registered with Clinicaltrial.gov (NCT04578704)., Results: At T4, the upper lip, lower lip, and upper incisors moved anteriorly (mean difference (MD) of 1.63 mm (SD 3.7), 0.48 mm (SD 1.1), and 0.54 mm (SD 0.97), respectively). The upper and lower incisors were proclined by 0.96 degrees (SD 2.1) and 1.11 degrees (SD 2.63), respectively. The interincisal angle was reduced by 0.56 degrees (SD 1.23). Only the upper incisor inclination (UII) change showed significant differences between groups (η² = 0.296; p = 0.015). Post-hoc comparisons revealed that the FBR and VFR groups exhibited greater proclination than the DR group (UII, MD = 3.33 degrees and 3.22 degrees, respectively). No differences were observed in OHIP-14[M] scores between the groups., Conclusion: All three retention protocols showed statistically small but clinically insignificant changes., Clinical Relevance: Dual retention offers better control in preventing upper incisor proclination in bimaxillary proclination cases., Trial Registration: This trial was registered with Clinicaltrial.gov (NCT04578704)., Competing Interests: Declarations. Ethics approval and consent to participate: Ethical approval was obtained from the Medical Ethics Committee, Faculty of Dentistry, Universiti Malaya with the reference number DF CD1910/0058(P) [Date First approval: 16 July 2019; Date Approval After Protocol Amendment: 13 January 2020]. Consent for publication: Consent to publish has been obtained from all individuals whose data, including any details or images, are included in the manuscript. Competing interests: The authors declare no competing interests., (© 2025. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

This study aimed to evaluate the effectiveness, pain, and satisfaction levels of patients treated with different thicknesses of clear aligners among class I maxillary mild crowding cases. Twenty-eight subjects were randomly divided into two groups. Group 1 were treated with 0.5 mm-thick aligners and group 2 were treated with 0.75 mm-thick aligners. Maxillary models were printed using a 3-dimensional printer and aligners were produced using a vacuum thermoforming machine. The amount of orthodontic tooth movement was evaluated by comparing pre- and post-treatment digital models and lateral cephalograms taken at the beginning and end of the treatment. Pain and satisfaction levels were measured before aligner insertion, at the 4th hour, 2nd day, 1st week, 1st month and at the end of the treatment. Increases in maxillary intercanine, interpremolar, and intermolar widths, and dental arch perimeter were significantly higher in group 2 (p < 0.05). The pain levels peaked at T1 and decreased gradually in both groups; group 2 demonstrated greater pain levels. Group 1 reported significantly greater satisfaction levels (p < 0.05). Aligner thickness is a key determinant of the extent of orthodontic tooth movement. Treatment with a 0.5 mm-thick aligner provides enhanced comfort for patients, but a 0.75 mm-thick aligner yields more efficient treatment results.Trial registration: The trial was registered on https://ClinicalTrials.gov retrospectively with the registration number of NCT06504498, on 16/07/2024., Competing Interests: Declarations. Competing interests: The authors declare no competing interests. Consent for publication: All the authors agree to the publication of this work., (© 2025. The Author(s).)

Objective: The aim of this randomized controlled trial (RCT) was to evaluate the spontaneous distorotation of upper first permanent molars and the transverse dentoalveolar changes on digital casts in growing patients following maxillary expansion treatment using either the Leaf Expander® or the rapid maxillary expander (RME), both anchored to the deciduous second molar., Trial Design and Setting: This study was a two-arm, parallel-assignment, RCT with a dual-centre design conducted at two teaching hospitals in Italy., Participants: Inclusion criteria included maxillary transverse deficiency, prepubertal development stage (cervical vertebra maturation stage [CVMS] 1-2) and early mixed dentition with fully erupted upper first permanent molars. Exclusion criteria were systemic diseases or syndromes, CVMS 3-6, agenesis of upper second premolars, unavailability of the second deciduous molar for anchorage and Class III malocclusion., Randomization: Patients were randomly assigned to the Leaf Expander® or RME group using a computer-generated randomization list created by a central randomization centre. Randomization was conducted immediately before the start of treatment., Intervention: The intervention involved treatment with either the Leaf Expander® or the RME. Both devices were anchored to the second deciduous molars. Following randomization, patients were further categorized based on the presence of no crossbite, unilateral crossbite or bilateral crossbite., Main Outcome Measure: The primary outcome measure was the distorotation of the upper first molar (U6). Secondary outcomes included measurements of interdental linear dimensions, specifically upper inter-canine width (53-63), upper inter-molar width (MV16-MV26) and upper inter-deciduous second molar width (55-65)., Blinding: The examiner analysing the digital casts was blinded to the treatment groups to prevent detection bias and ensure objective assessment. However, due to the nature of the intervention, blinding was not feasible for the patients and clinicians involved in administering the treatment., Results: A total of 150 patients were enrolled and randomly assigned to two groups: 75 to the Leaf Expander® group and 75 to the RME group. Recruitment started in November 2021 and was completed in November 2022. At the time of analysis, the trial was complete with no ongoing follow-ups. ANOVA tests revealed no significant differences between the three subgroups (no-cross, unilateral-cross and bilateral-cross) within both the Leaf Expander® and RME groups at T0. The Leaf Expander® demonstrated significantly greater distorotation in the unilateral crossbite subgroup compared to the RME (p = .014). In terms of total molar distorotation, the Leaf Expander® appliance showed a significantly greater effect (12.66°) compared with conventional RME (7.83°). Linear regression analysis demonstrated a significant correlation between the extent of expansion and the degree of molar rotation., Conclusions: Maxillary expansion resulted in significant spontaneous molar distorotation when the appliance was bonded to the second deciduous molars. The Leaf Expander® exhibited significantly greater molar distorotation compared with conventional RME. The degree of molar distorotation was correlated with the extent of expansion obtained on the second deciduous molar., Trial Registration: The trial was registered at ClinicalTrials.gov (ID: NCT05135962)., (© 2024 The Author(s). Orthodontics & Craniofacial Research published by John Wiley & Sons Ltd.)

Introduction: The objective of this study was to compare the differences in anchorage and torque control among the Tweed edgewise, Roth, and physiological anchorage Spee-wire systems (PASS) appliances (Zhejiang Xinya Technology Co, Ltd, Hangzhou, China)., Methods: A sample of 90 adolescent patients with Angle Class II Division 1 malocclusion (30 Tweed edgewise appliances, 30 Roth appliances, and 30 PASS appliances) with maximum anchorage requirements in the maxilla were collected for this study. The pretreatment baseline levels of the 3 groups were compared initially, and then the differences between the 3 appliances in anchorage and torque control were analyzed after superimposing the pretreatment and posttreatment lateral cephalograms and maxillary 3-dimensional (3D) digital models, respectively., Results: There was no statistical difference in the pretreatment baseline levels of 3 groups, including gender, age, sagittal skeletal types (ANB), vertical skeletal types (SN-GoGn), anchorage requirements, and occlusal plane inclination (SN-OP). After superimposing the pretreatment and posttreatment lateral cephalograms and 3D digital models, respectively, no statistical differences were observed between the measurement results obtained from lateral cephalograms and 3D digital models. Among the measurement variables assessed in this study, statistical differences were observed in the mesial displacement of maxillary first molars, the incisor retraction, and the torque variation of maxillary central incisors among the 3 groups. Specifically, the Tweed group exhibited lower mesial displacement of maxillary first molars compared with the PASS and Roth groups. Furthermore, the Tweed group exhibited the greatest amount of incisor retraction and torque variation of maxillary central incisors, followed by the Roth group and then the PASS group. The remaining measurement variables for the 3 groups showed no statistical differences, including vertical variation of maxillary first molars and central incisors, torque variation of maxillary first molars and canines, mesiodistal inclination variation of maxillary first molars and canines, width variation between maxillary first molars, and width variation between maxillary canines., Conclusions: Compared with contemporary preadjusted straight wire appliances, the Tweed edgewise appliance has superiority in molar anchorage control. In contrast, compared with the Roth appliances, the PASS appliances without any auxiliary anchorage devices could make full use of physiological anchorage to achieve adequate control of molar anchorage. Clinical orthodontists may need to pay extra attention to physiological anchorage. The difference in torque control varies depending on the respective characteristics of bracket designs., (Copyright © 2024 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.)

Background: The retrospective study examined changes in the root length and alveolar bone surrounding maxillary incisors in patients with skeletal Class III malocclusion treated by surgical orthodontic treatment with either fixed appliances (FAs) or clear aligners (CAs)., Methods: A total of 60 subjects were divided based on appliance type used. Cone beam computed tomography scans were taken at three stages: before treatment, after presurgical orthodontic treatment, and post-treatment for both groups. Vertical alveolar bone level and horizontal alveolar bone thickness (ABT) were measured at four heights (3, 6, and 9 mm from the cementoenamel junction, and the root apex), along with root length, at these time points., Results: Both groups showed a decrease in root length, with the CA group experiencing a significantly smaller reduction (0.4 ± 0.79 mm) compared with the FA group (0.64 ± 0.8 mm; P = 0.02). The FA group demonstrated more significant reduction in palatal ABT (P < 0.05) and greater root resorption, whereas the CA group exhibited considerable labial marginal bone resorption (P = 0.007) and a notable decrease in labiolingual inclination (P = 0.042)., Conclusions: The findings suggest that FA and CA might lead to decreased ABT and significant root resorption, with FA therapy likely resulting in more pronounced effects. Both modalities led to notable vertical bone loss, particularly, on the labial side of the maxillary incisors in the CA group during postsurgical orthodontic treatment. Preventing iatrogenic deterioration of periodontal support surrounding the incisors is crucial during presurgical and postsurgical phases., (Copyright © 2024 World Federation of Orthodontists. Published by Elsevier Inc. All rights reserved.)

Objective: The present clear aligner therapy (CAT) research focuses on isolating and reporting the biomechanical performance for three separate teeth, three translational movements and two flat trimlines at different heights. By identifying key patterns, the research seeks to inform the development of improved aligner designs, ultimately enhancing the effectiveness of clinical orthodontic treatments., Materials and Methods: In an in vitro setting using the Orthodontic Force Simulator (OFS), the biomechanical response of 30 aligners was investigated on three different teeth of a straight symmetric maxillary dentition (central incisor, canine and first molar). Each tooth was tested under two flat trimline conditions (trimmed at gingival margin, TL0; extended 2.0 mm below, TL2) and for three types of translational movements (palatal translation, mesial translation and intrusion). Forces and moments were reported at the centre of resistance for each displaced tooth as well as the two neighbouring teeth, evaluating a total of 18 distinct scenarios., Results: Findings indicate significant variability in the biomechanical responses based on tooth location in the arch, trimline height and movement performed. For palatal translations, the palatal force required to perform the movement was observed highest in molar cases, followed by canine and incisor cases, with a notable difference in the distribution of side effects, indicating a strong influence of tooth anatomy and position in the arch. Similarly, in mesial translations and intrusions molars experienced greater forces and moments than the corresponding movements applied on canines and incisors, but uniquely dispersed for each configuration tested. Regarding the shape of the aligner, TL2 consistently showed improved control over orthodontic movements compared to TL0. Neighbouring teeth frequently displayed compensatory reactions up to about half of the intensity observed on the tooth being moved, with notable variations from case to case., Conclusions: This research supports fundamental factors impacting CAT: Characteristic patterns in the direction and intensity of forces and moments are associated with each of the three translational movements tested. Tooth anatomy and arch location significantly influence the biomechanical performance of aligners, with an observed trend for molars to display higher forces and moments over canines and incisors, but distributed differently. The height of a flat trimline, specifically TL2, shows enhanced control over orthodontic movements. Additional findings revealed a compensatory activity of neighbouring teeth, which varies based on tooth region and movement type. It potentially could influence CAT outcomes negatively and merits attention in future investigations. These results support a tailored CAT method that improves aligner design for better force application. This method needs to be used alongside, and confirmed by, clinical knowledge. Future research should extend these findings to a wider range of clinical conditions for greater applicability in the day-to-day orthodontic practice., (© 2024 Institut Straumann AG. Orthodontics & Craniofacial Research published by John Wiley & Sons Ltd.)

Tip control in lingual orthodontics may be challenging because of the presence of a vertical slot and the particular configuration of the customized appliances. The aim of this in vitro experimental study was to investigate the role of the ligature-wire-slot system in achieving better tip control. A set of customized lingual brackets was obtained for a dedicated typodont made of extracted human teeth. A compression/traction machine tested two types of ligatures in combination with seven different wires, and the tipping angle of each configuration was derived. A statistically significant difference was found between ligatures when the complete set of data was tested. In addition, differences between ligatures were found when testing each wire separately. A statistically significant difference was found among all wires. Full-size wires showed the smallest angles, which correspond to the greatest efficiency of the slot-archwire-ligation system in terms of tip control, and this efficiency appeared to be ligature-related. The role played by the type of ligature was more relevant for undersized wires., (© 2024 The Author(s). European Journal of Oral Sciences published by John Wiley & Sons Ltd on behalf of Scandinavian Division of the International Association for Dental Research.)

Objective: This study aimed to compare the force degradation of intermaxillary elastics (IE) in vitro and in vivo while stretching the IE to a precise diameter., Materials and Methods: IE 3/16″ medium Dentaurum from five different batches of packaging were analyzed. The in vivo study involved 10 volunteers, of which 100 IE were examined. To achieve three times the original diameter of the elastic, the distance between the upper canine and the lower dental arch was measured. Buttons were then placed in the mouth accordingly, and IE and passive aligners were inserted for five sessions of 48 h each. To investigate in vitro, 100 IE were placed in an incubator set at 37°C in a humid environment and stretched three times their diameter. The force of the elastics was measured in both investigations using a force meter at 0, 2, 8, 24, and 48 h., Results: In all patients except one, the three times diameter distance extended from the upper canine to the lower second premolar. The force degradation in vivo at 2, 8, 24, and 48 h was 20.58%, 26.78%, 34.81%, and 38.56% and in vitro was 16.38%, 22.83%, 28.32%, and 30.78%., Conclusions: The amount of stretching of IE varies for each patient when using standard insertion points. The force of IE decreases exponentially, the force degradation in vivo being higher. The clinician must consider the force decrease when advising the patient of the time interval to change the elastics., (© 2025 The Author(s). Clinical and Experimental Dental Research published by John Wiley & Sons Ltd.)

This study investigates the moments generated when applying third-order bends to lingual brackets with different slot shapes and wires made of different materials. Three types of lingual brackets with different slot shapes: 0.018×0.018-inch square slot self-ligation bracket (AL-bracket); 0.018×0.025-inch slot self-ligation bracket (CL-bracket); 0.018×0.025-inch slot self-ligation bracket (ST-bracket). Wires of three different materials were measured. The torque value generated during torque application was measured using a torque gauge. The AL-bracket had a significantly larger torque moment than the CL- and ST-brackets at the same angles. The CL-bracket had the smallest torque moment of the three for the square wire; however, the CL-bracket revealed a larger torque moment than the ST-bracket for the rectangular wire. The torque moment of Ti-Ni wires was observed the smallest. In lingual orthodontic treatment, the results suggested the shape of the lingual bracket slot and the wire material should be considered when adjusting and applying third-order bends.

Objective: To investigate the effects of modified twin-block appliances (MTBA) on obstructive sleep apnea (OSA) and mandibular retrognathia and the changes in the upper airway, hyoid bone position, and hypoxia-related inflammatory marker levels in children with OSA., Methods: This study included children with OSA and mandibular retrognathia and those with class I without mandibular retrognathia (n = 35 each). The experimental group comprised children with OSA and mandibular retrognathia managed using MTBA. Postoperative and preoperative polysomnography, lateral cephalometric radiographs, and peripheral blood samples were collected. The control group comprised children with class I without mandibular retrognathia., Results: Following MTBA management, the experimental group exhibited decreased apnea-hypopnea index and increased lowest arterial oxygen saturation level (P < 0.05). Sella- and subspinale-nasion-supramental angles significantly increased and decreased, respectively (P < 0.05). Posterior soft palatal-posterior pharyngeal wall distance, apical palatal-middle pharyngeal wall distance, posterior airway space, epiglottis valley-hypopharyngeal wall distance, hyoid-prevertebral plane distance, and distance from the superior anterior point of the hyoid bone to the inferior anterior point of the third cervical spine significantly increased, whereas distance from the superior anterior point of the hyoid bone to the mandibular plane decreased (P < 0.05)., Conclusions: Children with OSA (n = 35) were managed using MTBA, which relieved the mandibular retrognathia deformity, widened the upper airway space, moved the hyoid bone forward and upward, and improved the sleep monitoring indicators. Thus, MTBA can achieve satisfactory therapeutic effect in children with OSA and mandibular retrognathia with mandibular advancement., Competing Interests: Declarations. Ethics approval and consent to participate: The project was approved by the Ethics Committee of the Children’s Hospital Affiliated to Chongqing Medical University. Approval Number: (2021)IRB(STUDY)NO.22.All procedures were performed in accordance with the ethical principles of the Helsinki declaration. Informed consents were obtained from all participants and their parents. Consent for publication: Not applicable. Clinical trial number: This study has been registered through the National Medical Research Registration and Archival Information system, and Clinical trial number is: MR-50-23-019230. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

Direct printed aligners (DPAs) offer benefits like the ability to vary layer thickness within a single DPA and to 3D print custom-made removable orthodontic appliances. The biocompatibility of appliances made from Tera Harz TA-28 (Graphy Inc., Seoul, South Korea) depends on strict adherence to a standardized production and post-production protocol, including UV curing. Our aim was to evaluate whether design modifications that increase layer thickness require a longer UV curing time to ensure biocompatibility. Specimens with varying layer thickness were printed to high accuracy using Tera Harz TA-28 and the Asiga MAX 3D printer (Asiga SPS ™ technology, Sydney, Australia). UV curing durations were set at 20, 30 and 60 min. Cytotoxicity was evaluated using the AlamarBlue assay on human gingival fibroblasts. Cell viability decreased with increasing specimen thickness (significant for 2 mm [p < 0.001], 4 mm [p < 0.0001], and 6 mm [p < 0.01]) under the manufacturer-recommended 20-min UV curing. Extending the curing time did not improve cell viability. However, cell viability never decreased by more than 30%, meeting EN ISO 10993-5 standards for non-cytotoxicity. The standard 20-minute UV curing protocol ensures the biocompatibility and patient safety of Tera Harz TA-28 for material thicknesses up to 6 mm., Competing Interests: Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

Background: The demand for orthodontic treatment using clear aligners has been gradually increasing because of their superior esthetics compared with conventional fixed orthodontic therapy. This study aimed to evaluate and compare the compressive strength of three-dimensional direct printing aligners (3DPA) with that of conventional thermo-forming aligners (TFA) to determine their clinical applicability. In the experimental group, the 3DPA material TC-85 (TC-85 full) was used to create angular protrusions called rectangular pressure areas (RPA). A protrusion akin to the power ridge typically employed in conventional TFAs was created using glycol-modified polyethylene terephthalate (PETG; Control 1). RPA was created using the same TC-85 without filling the protrusions (TC-85 blank; Control 2). Compression cycle tests were conducted on an LTM 3 h electrodynamic testing machine (Zwick Roell, Germany), with 500 cycles and compression depths of 100, 300, 500, and 700 µm. Twenty specimens were tested for PETG, 17 for the TC-85 blank, and 19 for the TC-85 full., Results: Changes in the compressive force were assessed based on the material and thickness. The results indicated significantly higher and broader ranges of compressive strength for specimens fabricated with the 3DPA material TC-85 compared with those fabricated using PETG. Among the TC-85 specimens, TC-85 full demonstrated the highest statistically significant compressive strength ., Conclusions: 3DPA technology enables precise modifications in the shape and inner thickness at specific dental sites, including the creation of ridges in targeted areas, of aligners. These alterations enhance the biomechanical capability of aligners to exert selective forces necessary for desired tooth movement while reducing the number of attachments, thereby demonstrating the clinical potential of 3D-printed aligners in orthodontic treatment., Competing Interests: Declarations. Competing interests: The authors declare no competing interests. Ethics approval and consent to participate: All human research procedures were followed in accordance with the ethical standards of the committee responsible for human experimentation (institutional and national), and with the Helsinki Declaration of 1975, as revised in 2013. This study was reviewed and approved by the Institutional Review Board (IRB) of Ajou University Hospital (IRB No: AJOUIRB-EX-2024-280)., (© 2025. The Author(s).)

Background: Anterior open bite is a challenging condition for pediatric dentists and orthodontists as it causes aesthetic, speech, feeding, and psychological problems; this emphasizes the need for early diagnosis and interception of this malocclusion., Aim: This study aimed to evaluate the effects of prefabricated metal-bonded tongue tamers and customized bonded spurs in the early treatment of anterior open bite., Materials and Methods: A sample of seventy-five children aged 7-9 years were assigned into three groups in which anterior open bite was treated using tongue tamers (group-I), customized composite bonded spurs(group-II), and conventional fixed palatal cribs (group-III). Study model and cephalometric x-ray evaluations were done before and after a three-month follow-up. Data was gathered and statistically analyzed using ANOVA and Bonferroni tests., Results: Model overbite at central and lateral incisors was increased in all groups. The highest increase was found in group-I(3.16 ± 1.17, 2.81 ± 0.94)and group-III(3.08 ± 1.10,2.99 ± 1.00) though the difference was not statistically significant. Also, cephalometric overbite was non-significantly increased in all groups with a high increase in group-III(3.13 ± 1.10). Overjet decreased in all groups, with the greatest reduction observed in group-I(-2.58 ± 1.02 and -2.47 ± 0.80 in model and cephalometric respectively) and was significantly different from group-II using pairwise analysis. There was a decrease in SNA and ANB in all groups with more significant improvement in groups-I(-1.20 ± 0.88,-1.65 ± 0.74) and -III(-1.31 ± 0.92, -1.62 ± 0.75) than group-II(-0.63 ± 0.46, -0.90 ± 0.43). Moreover, FMA measurements decreased significantly in group-I (-2.6 ± 1.11). Regarding SNB measurement, there was a non-significant increase in all three groups with the highest increase in group-I(0.49 ± 0.48) followed by group-III(0.34 ± 0.63). The U1/FHP and L1/GoGn angles were non-significantly decreased in all tested groups with the highest decrease in group-I(-1.76 ± 1.00 and-2.54 ± 0.87 respectively)., Conclusion: Early treatment of anterior open bite, along with tongue tamers' simplicity and aesthetics promoted the malocclusion correction and occlusal function restoration., Trial Registration: ClinicalTrials.gov, NCT05792553 , "Effects of Tongue Tamers as an Early Treatment of Anterior Open Bite", Retrospectively registered: 31/03/2023., Competing Interests: Declarations. Ethics approval and consent to participate: The ethical committee (REC) of Tanta University's Faculty of Dentistry provided ethical permission for this study, with code (#R-ORTH-2-23-5) following the Helsinki Declaration of 1964 and the ensuing revisions. The aim of the research was disclosed to the patient's parents, and parents provided informed written consent. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

In recent years, a segmental approach to Class II correction has gained popularity among orthodontists. This concept is best represented by the Carrière Motion 3D™ Class II Appliance (CMA), which is an efficient and effective appliance for the treatment of Class II malocclusions. Although it is original and innovative, it also has some inherent flaws that can potentially interfere with its daily use. A segmental approach is described, based on a section of 0.016 × 0.022-inch stainless steel archwire connected to a molar band distally and to a bracket on the mesial side. This simple alternative presents a 'do-it-yourself' and an easy-to-construct mechanism that employs the same principles and identical mechanics to achieve Class II correction yet overcomes most of the disadvantages of other modalities. In our clinic, we found that this optional, useful sectional appliance can correct Class II malocclusion effectively, predictively and on a regular basis., Competing Interests: Declaration of conflicting interestsThe author declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Twin block appliances are commonly used to treat skeletal class II malocclusion. However, many adverse effects, such as lower incisor protrusion and a bulky nature, can be observed. To overcome these effects, a modified twin block was designed, which uses vacuum-formed hard plates (VFPs) instead of acrylic plates. This clinical trial evaluated the skeletal and dentoalveolar changes resulting from a modified twin block (aesthetic twin block) (ATB) in comparison with conventional twin block (CTB) in addition to levels of esthetics and discomfort. A two-arm parallel group randomized clinical trial was performed at the Department of Orthodontics, University of Damascus, Syria. Fifty-two patients (33 females and 19 males) aged 12.23 ± 0.77 years with skeletal class II division 1 malocclusion caused by mandibular retrognathism were included. The participants were randomly assigned to a study group according to a simple randomization method using a numbered and sealed envelope. The experimental group was treated with an aesthetic twin block, and the control group was treated with a conventional twin block. Sixteen angular variables and eleven seventeen linear variables (measured in millimeters) were evaluated before the treatment (T0) and at the end of the active phase of the treatment (T1) on lateral cephalometric radiographs and dental casts to study the skeletal and dentoalveolar changes, and a questionnaire was used to assess the levels of esthetic and discomfort. There was a statistically significant change in the ANB angle between the ATB group (-2.70 ± 0.84) and the CTB group (-1.92 ± 0.81°) (P = 0·002) and between the SNB angle of the ATB group (2.72 ± 1.54°) and the CTB group (1.72 ± 1.41°) (P = 0·02). The Jarabak ratio decreased significantly in the CTB group (-0.65 ± 1.37%) (P = 0.02) and increased significantly in the ATB group (0.84 ± 1.44%) (P = 0.007), with significant differences between the two groups (P = 0.000). The change in upper incisor angulation was statistically significant (-1.88 ± 1.48°) for the ATB group and (-3.5 ± 4.18°) for the CTB group (P = 0·001). The change in lower incisor angulation was 1.34 ± 2.08° for the ATB group and 3.88 ± 2.47° for the CTB group, which was statistically significant (P = 0·000). ATB had more control of vertical growth, lower incisor and upper incisor angulation and was more aesthetically acceptable.Trial registration: (NCT05418413) (14/06/2022)., Competing Interests: Declarations. Competing interests: The authors declare no competing interests. Ethics approval and consent to participate: The institutional review board and the ethical review committee of Damascus University (No. 1205–06–12–2021) approved this study. Written informed consent was obtained from each patient., (© 2025. The Author(s).)

Introduction: It is known that the stability of the results obtained with orthodontic treatment depends, in addition to the functional and aesthetic aspects, also on the adequate planning of the retention devices, the patient's compliance with this new phase, and the physiological changes that the human body experiences over the years, throughout the craniofacial aging process., Objective: This article discusses the importance of the orthodontic retention phase and the influence of diagnosis, planning and execution of corrective treatment of malocclusions, in order to achieve the expected success., Methods: Throughout the text, different types of retainers and approaches during this phase will be presented, with the aim of ensuring the stability of the results obtained after correcting problems in the vertical, transverse and anteroposterior directions., Results: Orthodontic retainers are not all the same. The retention protocol must be performed in an individualized and planned manner, taking the initial dental positions as a reference., Conclusions: The orthodontist must inform the patient and parents about important aspects of how to maintain the occlusion achieved with orthodontic treatment. The retainers installed after the end of corrective treatment are not everlasting, they can suffer damage with use and must be replaced. Therefore, the patient must be aware of the importance of using retainers as prescribed by the orthodontist, and of returning for scheduled review appointments.

Introduction: This randomized clinical trial compared arch dimensional changes, dentoskeletal changes, and the rate of overbite correction in deep bite adults treated with fixed appliances and either maxillary incisor bite turbos (IBT) or canine bite turbos (CBT)., Materials and Methods: Forty-six deep bite subjects treated with fixed appliances were randomized into IBT (n = 23) and CBT (n = 23) groups. Changes in intercanine width (ICW), arch height (AH), and Little's Irregularity Index (LII) were analyzed from before treatment (T 0 ) to 3 months after aligning with 0.012" NiTi archwires in both arches (T 1 ). Cephalometric changes between T 0 and the visit when normal overbite was achieved (T 2 ) were assessed. Within-group and between-group comparisons were analyzed at a significance level of 0.05., Results: In both groups, mandibular ICW, and maxillary and mandibular AH significantly increased while maxillary and mandibular LII decreased. Maxillary and mandibular incisor proclination and molar extrusion were observed. The IBT group showed significantly greater changes in mandibular ICW, maxillary and mandibular AH, and mandibular incisor proclination than the CBT group. However, the overbite correction rate and the LII reduction were not significantly different between the groups., Conclusions: The IBT and CBT produced similar effects on arch dimensions and dentoskeletal changes. However, the IBT group demonstrated greater arch dimensional changes., Clinical Relevance: Clinicians may consider IBT if flaring incisors is desired. Alternatively, CBT is better for cases with limited incisor proclination and where minimizing arch dimension change is needed, such as in narrow ridge situations., Clinical Trial Registration: The trial was registered at Thai Clinical Trial Registry on https://www.thaiclinicaltrials.org , under the identifier TCTR20230811013., Competing Interests: Declarations. Ethics approval and consent to participate: The study was reviewed and approved by the Ethics Committee on Human Research of the Faculty of Dentistry, (deleted for double-anonymized peer review) (ethical approval No. EC6602-006) on 23 February 2023. Participants or guardians were asked to sign a consent form to participate in this research. Competing interests: The authors declare no competing interests., (© 2025. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objectives: To address the high surface roughness and poor optical properties of three-dimensional (3D) printed orthodontic clear retainers, an alternative post-processing protocol was investigated with the goal of achieving improved surface, optical, and mechanical properties while preserving dimensional accuracy., Materials and Methods: Samples were prepared from two biocompatible methacrylate-based 3D-printing resins (Formlabs Dental LT Clear V2, NextDent OrthoFlex) and one thermoplastic material (Duran). For the 3D-printed resins, one group was post-processed by rinsing in isopropyl alcohol, while another group was centrifuged before post-curing in glycerine. Three different testing conditions were used: dry, wet (24-h water immersion), and aged (thermocycling for 10,000 cycles). Surface characteristics were evaluated qualitatively and quantitatively. Optical properties were assessed for transparency and colour stability, while mechanical properties were elicited from tensile and microhardness tests. Water sorption and solubility were calculated. Samples mounted on a dental model were scanned by micro-computed tomography to measure thickness and gap width., Results: 3D-printed samples post-processed by centrifugation showed significantly decreased surface roughness and improved visible light transmission, colour stability, tensile strength, and hardness. The centrifuged samples showed significantly increased thickness, while designing an offset equal to this thickness improved the adaptation., Conclusions: Post-processing by centrifugation produces surface coating that enhances the surface and optical properties of the 3D-printed orthodontic retainers, while curing in an oxygen-free environment improves their mechanical properties. Design modifications may be necessary for this protocol to ensure proper adaptation to the dentition., Clinical Relevance: Proper design and post-processing protocols are necessary to achieve the desired properties of orthodontic clear retainers., Competing Interests: Declarations. Ethics approval and consent to participate: Not applicable. This was an in vitro experimental study which did not involve any human subjects. Consent for publication: Not applicable. This research did not utilize any individual person’s data. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

Background: Proper torque control is crucial to the outcome of orthodontic treatment. This study aimed to employ finite element analysis to compare the torque capabilities of a novel spherical self-ligating bracket with a lock-hook system against those of commonly used passive self-ligating and conventional bracket systems, as well as to reveal the biomechanical changes in the periodontal ligament (PDL) during torque expression., Methods: A maxillary right central incisor, along with its PDL and alveolar bone, were modeled. Three types of brackets were selected: a spherical self-ligating bracket with a lock-hook system, a passive self-ligating bracket (Damon), and a conventional bracket (Discovery). Each bracket was equipped with a 0.022-inch slot and a 0.019 × 0.025-inch stainless steel archwire. A palatal root torque of 20° was applied. The torque moment, as well as the von Mises stress and strain in the PDL, were calculated. A clinical case involving the lingual inclination of the upper anterior teeth was utilized to assess the feasibility of using the spherical self-ligating bracket with the lock-hook system to express torque., Results: At a twist angle of 20°, the maximum torque generated by the spherical self-ligating bracket with a lock-hook system (27.8 N·mm) was approximately 1.6 times greater than that of the Damon bracket (17.5 N·mm) and the Discovery bracket (17.3 N·mm). As the twist angle increased, both the von Mises stress and the strain in the PDL also increased. When the maximum PDL stress was less than 0.026 MPa and the percentage of the PDL good strain area (defined as the area with PDL strain ≥ 0.3%) exceeded 50%, the torque range for the maxillary incisor was between 10.2 and 17.5 N·mm. The clinical case demonstrated that the use of the spherical self-ligating bracket with the lock-hook system effectively corrected the unfavorable linguoclination of the maxillary incisors., Conclusions: The spherical self-ligating bracket with a lock-hook system can significantly enhance torque expression. The optimal torque range for the maxillary incisor is between 10.2 and 17.5 N·mm., Competing Interests: Declarations. Ethics approval and consent to participate: This study was conducted in accordance with the Declaration of Helsinki. The present study was approved by Ethics Committee of the First Affiliated Hospital of Sun Yat-sen University ([2023]800). Informed consent was obtained from all of the participants in this study for clinical information and images. Consent for publication: Available (if requested). Clinical trial number: Not applicable. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

Purpose: This study aimed to evaluate the dental and skeletal stability one year after Miniscrew-Assisted Rapid Palatal Expansion (MARPE) by using 3D image data., Methods: Patients with transverse maxillary deficiency from the age of 16 onwards were enrolled consecutively in this prospective longitudinal cohort study. The MARPE appliance was digitally and individually designed and fabricated. Cone-beam computed tomography (CBCT) scans and intra-oral scans (IOS) were acquired before the start of MARPE treatment (T0), immediately after active expansion (T1) and one-year post-expansion (T2). Nasal floor width (NFW), palatal alveolar width at the first molar (M1) and first premolar (P1) (PAW), nasal cavity width (NCW), intermolar width (IMW) and interpremolar width (IPW) were measured to assess the immediate (ΔT0-T1) and net (ΔT0-T2) skeletal and dentoalveolar expansion and relapse (ΔT1-T2). Potential correlations with age, sex and midpalatal suture maturation (MSM) stage were also investigated., Results: Thirty-one patients (6 men, 25 women, mean age: 26.2 years) were included. The mean follow-up time (T0-T2) was 12.2 months. The initial NFW increase demonstrated a relapse of 0.6 ± 1.2 mm, or 11.6% of the initial expansion (p < 0.01). Expansion at the alveolar level remained stable during the follow-up. IPW also remained stable during the follow-up (4.2 ± 1.3 mm at T1; 4.4 ± 2.6 mm at T2). IMW exhibited a relapse of 3.8 ± 2.1 mm, or 60.2% of the initial expansion (p < 0.001) during T1-T2. There was no statistically significant correlation between stability and age, sex and MSM stage., Conclusions: MARPE is an effective therapy for the correction of transverse maxillary discrepancy in late adolescents and adults, achieving a clinically stable skeletal outcome one year after expansion., Competing Interests: Declarations. Ethical approval: The study was approved by the Radboud University Medical Center Institutional Review Board (IRB no. 2019–5898). Consent to participate: A written informed consent was obtained from all study participants. Consent to publish: The authors affirm that human research participants provided informed consent for publication of the images in Figs. 1 and 2. Competing interests: The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction: This study investigated the physical, mechanical, and optical properties of 3-dimensional (3D) printing resins compared with thermoplastic materials to evaluate their suitability for the fabrication of orthodontic clear retainers., Methods: Samples were prepared from thermoplastic sheets (Duran [Scheu-Dental GmbH, Iserlohn, Germany] and Zendura [Bay Materials LLC, Fremont, Calif]) and biocompatible 3D-printing resins (Dental LT Clear V2 [Formlabs Inc, Somerville, Mass] and OrthoFlex [Nextdent BV, Soesterberg, The Netherlands]) according to the manufacturer's instructions. The materials were characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, and water sorption tests. Mechanical properties were assessed by tensile tests and hardness under 3 different conditions: dry, wet (24-hour water immersion), and aged (thermocyled for 10,000 cycles). Surface characteristics were qualitatively and quantitatively evaluated by scanning electron microscopy and 3D confocal imaging, respectively. Optical properties were assessed by ultraviolet-visible spectroscopy and color stability tests by immersion into various staining solutions., Results: The mechanical properties of the 3D-printing resins were more markedly altered in different testing conditions (dry, wet, and aged) than in thermoplastic materials. The surface roughness, transparency, and color stability of 3D-printing resins are significantly inferior, especially NextDent OrthoFlex., Conclusions: The evaluated 3D-printing resins are more brittle and less ductile compared with the thermoplastic materials. The 3D-printing resins also do not meet the clinical thresholds of surface roughness and optical properties for the fabrication of orthodontic clear retainers. Further postprocessing of the 3D-printing resins may be required to improve these properties., (Copyright © 2025 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.)

Objectives: To compare the biomechanics of labial and lingual fixed orthodontic treatment options for a simulated curve of Spee malocclusion., Materials and Methods: An in vitro electromechanical orthodontic simulator was used to measure the three-dimensional forces and moments on each tooth of a mandibular arch. Labial and lingual brackets, both with 0.018-inch slot sizes, were bonded to mechanical teeth. Three archwire forms were considered: labial straight, lingual straight, and lingual mushroom. The simulator was set in a passive levelled position with 0.016-inch × 0.022-inch stainless steel archwires, then teeth were moved to a curve of Spee maloclussion with the first premolar intruded 1.5 mm and the canine and second premolar intruded 0.75 mm. Two-way mixed multivariate analysis of variance (α = 0.05) was used to compare forces and moments generated among the three archwires., Results: Statistical differences were found in 55 of 63 comparisons of forces and moments between archwire types for each tooth around the arch. The lowest force magnitudes were measured for labial straight archwires at each tooth position. The lateral incisor experienced the largest gingival forces with all archwire forms. The first premolar and first molar experienced labial-lingual crown tipping moments in opposite directions between labial and the two lingual archwire forms., Conclusions: Biomechanical differences between labial, lingual straight, and lingual mushroom treatment modalities for the correction of curve of Spee misalignments were elucidated. Labial straight archwire exerted the lowest force magnitudes overall. For both lingual archwire forms, the labial-lingual inclination of the first premolar could be highly variable during levelling., (© 2025 by The EH Angle Education and Research Foundation, Inc.)

Introduction: Directly printed aligners (DPAs) are gaining in popularity, potentially streamlining manufacturing, decreasing environmental waste, and offering enhanced adaptation and tailoring. This transition has been facilitated by advances in materials, software, and production. Although DPAs may have enhanced versatility and application in the management of more complex malocclusions, there is little research evaluating their effectiveness., Methods: A total of 54 patients undergoing treatment with DPAs were evaluated for occlusal improvement, overall treatment duration, and adverse effects. Regression models were fit to evaluate the association between the need for refinement, final peer assessment rating (PAR) score, and independent variables, including the total number of aligners and treatment indications., Results: The mean number of aligners in the initial plan was 7.1 ± 2.9 and 5.1 ± 4.3 in maxillary and mandibular arches. Refinement was required in 40.8% (n = 20). The pretreatment PAR score of 17.01 ± 7.93 showed a significant improvement (86.6%), with a final PAR score of 2.25 ± 1.15. Minor complications were noted in 3 participants. The need for refinement was unrelated to the total number of aligners (odds ratio, 1.05; 95% confidence interval, 0.94-1.18; P = 0.36). There was weak evidence of an association between the final PAR score and the total number of aligners (odds ratio, -0.03; 95% confidence interval, -0.07 to 0.003, P = 0.07)., Conclusions: On the basis of this preliminary retrospective evaluation, DPAs may be used to manage mild-moderate malocclusion, producing a significant reduction in PAR score. Nevertheless, additional prospective research is required to confirm these findings and compare the relative merits of DPAs to alternatives., (Copyright © 2025 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.)

Purpose: The efficiency of dentoalveolar compensation involving both jaws for posterior crossbite correction using computer-aided design/computer-aided manufacturing (CAD/CAM) expansion and compression archwires was evaluated. Treatment outcome was tested against the null hypothesis that the transverse correction achieved would be significantly smaller than planned., Methods: This retrospective study included 64 patients (mean age 23.5 years, median 17.0, minimum/maximum: 9.0/63.0, standard deviation 13.7) with uni- or bilateral posterior crossbite. In all consecutively debonded patients, expansion and/or compression archwires were used for dentoalveolar correction involving both jaws. Plaster casts prior to (T1) and following treatment (T2) with completely customized lingual appliances (CCLA) were compared with the treatment plan represented by an individual target set-up. The statistical analysis was carried out using the Schuirmann TOST (two one-sided t‑tests) equivalence test on the basis of a one-sample t‑test with α = 0.025 to one side. The non-inferiority margin was set at δ = 0.5 mm., Results: All posterior crossbites could be corrected by dentoalveolar compensation involving both jaws. The mean total correction achieved was 6.9 mm (mean maxillary expansion: 4.3 mm/mean mandibular compression: 2.6 mm) with a maximum of 12.8 mm. The transverse corrections achieved in both arches at T2 were equivalent to the planned corrections in the set-up (p < 0.001)., Conclusion: The results of this study indicate that CAD/CAM expansion and compression archwires can be an efficient tool to achieve the desired correction in patients with a posterior crossbite even in more severe cases., Competing Interests: Declarations. Conflict of interest: D. Wiechmann is the inventor of the WIN system. The WIN system is manufactured by Dirk Wiechmann Lingual Systems and Dirk Wiechmann is the owner of this company. Ethical standards: This retrospective cohort study was approved by the ethical committee of the Hannover Medical School, Hannover, Germany (3151-2016)., (© 2023. The Author(s).)

Objectives: To evaluate the accuracy of occlusal splints printed in different orientations by liquid crystal display technology., Methods: An occlusal splint was digitally designed, and additively manufactured using an LCD printer (Phrozen Sonic 4k, Phrozen) at three orientations relative to the printer building plate: 0, 45, and 70 degrees (n=10). The 3D-printed occlusal splints were digitised using a desktop scanner, resulting in experimental meshes. The meshes were analysed in a metrology software program, comparing the experimental ones with the initially designed occlusal splint (trueness) and each other within the same group (precision). The discrepancies were shown in a colour map and the root mean square indicated the magnitude of the total discrepancy between the meshes. Kruskal-Wallis test was used (α=0.05) followed by post-hoc Dunn's test., Results: There was no statistical difference in trueness among the groups (P=0.086); however, splints printed at 70 degrees showed better precision compared to those printed at 0 (P<0.001) and 45 degrees (P<0.001). The splints printed at 0 and 45 degrees exhibited a similar discrepancy pattern, with highest values concentrated in the posterior segment-positive on the buccal surface and negative on the lingual surface of molars. In contrast, splints printed at 70 degrees had highest discrepancy values in both anterior and posterior segments, with an inverted pattern on molars., Conclusion: The accuracy of occlusal splints was affected by the different orientation in terms of precision, with 70 degrees resulted in highest precision compared to 0 and 45 degrees. No difference was found in terms of trueness. Higher discrepancies were found located in molars and incisal edge of anterior teeth., Clinical Significance: 3D-printing using LCD technology stands out for its affordability and good resolution, however the optimal printing angle remains unclear. Vertical positioning allows more objects to fit on the printer building plate, while horizontal positioning reduces print time. According to literature, for DLP printers, a 0-degree angle provides good accuracy for occlusal splints, whereas a 90-degree angle results in lower accuracy. This study found that for LCD printers, 0, 45, and 70 degrees had similar trueness, with 70 degrees offering the highest precision. Thus, vertical positioning at 70 degrees can be a safe choice for the accuracy of occlusal splints printed on LCD technology., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Purpose: The aim of this study was to show a possible correlation between the mean wear time of Hawley retainers and long-term mandibular arch stability as assessed via wear time analysis with microsensors., Methods: This longitudinal retrospective study comprised 47 subjects (mean age 16.30 ± 1.06 years) having been treated with a nonextraction protocol and presenting moderate crowding at pretreatment. For retention, all patients were instructed to use a mandibular Hawley retainer for 12 months, and wear time was documented every 3 months during a posttreatment period of 6 months using TheraMon software. These individuals were divided into two groups. Those who adhered to a wear time equal to or more than 12 h/day (group 1A; N = 17) and those who complied for less than 12 h/day (group 2A; N = 30) were compared with respect to changes of the mandibular arch during the first 6 months of retention. Furthermore, a subgroup of 28 patients who completed a 12-month follow-up period were again divided into two groups: the individuals in group 1B (N = 12) adhered to a wear time equal to or more than 8 h/day, while those in group 2B (N = 16) complied for less than 8 h/day. Little's Irregularity Index, intercanine and intermolar widths, arch length, overjet, and overbite were measured on mandibular models taken at pretreatment (T0) and posttreatment (T1), as well as 6 months (T2) and 12 months (T3) after debonding. Pearson correlation test, independent samples t‑test, and Mann-Whitney U test were used for statistical evaluation., Results: From T1 to T2, group 1A and group 2A showed a significant relapse in intermolar width with a difference in the median value of 0.38 mm (p = 0.019). At the complete 12-month follow-up, the increase in Little's irregularity score was significantly greater in group 2B (2.54 ± 1.29 mm) than in group 1B (1.32 ± 1.03 mm; p = 0.012). The established wear time measurements showed significant negative correlations with the Little's irregularity score and overjet changes between T1 and T3 (p < 0.05)., Conclusions: The results emphasized that the use of a retainer should not fall below a level of at least 8 h/day., Competing Interests: Declarations. Conflict of interest: E. Atik, T. Taner and M. Aksu declare that they have no competing interests. Ethical standards: All procedures performed in studies involving human participants or on human tissue were in accordance with the ethical standards of the institutional research committee and with the 1975 Helsinki declaration and its later amendments or comparable ethical standards. Ethical approval was obtained from the noninterventional Research Ethics Committee of Hacettepe University (number: GO 19/630). Written informed consent was provided by the parents/legal guardians of the patients prior to study commencement., (© 2023. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Objectives: To compare the effect between three different reverse curve of Spee (RCOS) archwires: 0.016 × 0.022-inch Nickel-Titanium and 0.019 × 0.025-inch stainless steel (SS) with and without crown labial torque (CLT) on lower incisors during deep overbite treatment., Materials and Methods: Eighty subjects with deep overbite were randomly divided into three groups: the first group (mean age: 20.5 years) received SS RCOS with CLT, the second group (mean age: 19.4 years) was treated with 0.019 × 0.025-inch SS RCOS with zero CLT, the third group (mean age: 18.2 years) was treated with rocking-chair nickel-titanium (NiTi) 0.016 × 0.022-inch with RCOS. Two lateral cephalometric images were taken for each patient, one after alignment and the second after deep bite correction. These images were superimposed using the corpus axis to study the lower incisor horizontal and vertical changes., Results: The lower incisor angular change was significantly smaller in Group II (-0.3°) compared to Group I (4.8°) and Group III (6.0°, P ≤ .001). Lower incisor anterior movement was reduced in Group II compared to Group I (P = .014) and Group III (P = .008). Group III showed significantly more downward movement of the lower Incisors (P ≤ .001). The three groups showed comparable amounts of true intrusion (1 mm, P = .536)., Conclusions: 0.016 × 0.022-inch NiTi and 0.019 × 0.025-inch SS with crown labial torque RCOS archwires resulted in similar proclination and forward movement of the lower incisors. Removal of anterior crown labial torque from the 0.019 × 0.025-inch SS RCOS archwire prevents lower incisor proclination and forward movement., (© 2025 by The EH Angle Education and Research Foundation, Inc.)

Objectives: To compare the accuracy and chair time of self-ligating brackets using direct bonding, traditional indirect bonding (IB), and computer-aided design/computer-aided manufacturing (CAD/CAM) IB techniques after orthodontic leveling and alignment., Materials and Methods: Forty-five patients were randomly assigned to three bonding groups (G1 [n = 15], G2 [n = 15], and G3 [n = 15]). Evaluation after the alignment and leveling phases used two parameters of the objective grading system of the American Board of Orthodontics for root parallelism and posterior marginal ridges, assessed using panoramic radiographies (PR I and PR II), a digital model, and a plaster model. Blinding was only applied for outcome assessment. No serious harm was observed except for gingivitis associated with plaque accumulation., Results: Although G3 showed better numerical results, they were not statistically significant in the radiographic or model evaluations (P > .001). Mean chair time was significantly shorter in G3 (1.1 ± 11.8 min) vs. G1 (56.7 ± 7.3 min) and G2 (52.8 ± 8.3 min; P < .001)., Conclusions: The CAD/CAM IB system for self-ligating brackets was as effective as conventional methods, with a shorter chair time., (© 2025 by The EH Angle Education and Research Foundation, Inc.)

Objectives: To determine whether the achieved mandibular central incisor lingual root torque (LRT) changes matched the planned changes after treatment with an initial series of Invisalign aligners when ≥10° of torque change was planned., Materials and Methods: A sample of adult patients who underwent treatment with the Invisalign appliance between 2013 and 2021 were evaluated. The pretreatment, planned, and achieved posttreatment digital models were measured using Geomagic Control X metrology software. The effect of age, number of prescribed aligners, sex, the presence of power ridges (PRs), and differing weekly wear protocols (WPs) in relation to the achieved LRT changes were determined., Results: Seventy mandibular central incisors from 35 patients satisfied inclusion criteria. The accuracy of the achieved lower incisor LRT compared with that planned was 58.2%. Underexpression of planned torque changes was observed in most incisors (N = 66; 94.3%), with a clinically significant shortfall (≥5°) observed in 68.6% (N = 42) teeth. Patient age, sex, the WP, or the presence of PRs did not influence the differences between planned and achieved outcomes (P > .05). The prescribed number of aligners was influential in the difference between the planned and achieved torque outcomes (P < .01)., Conclusions: Underexpression of mandibular central incisor root torque was observed in most incisors in patients when ≥10° change in LRT was planned. Lower incisor LRT was not significantly affected by the presence of PRs or differences in WPs., (© 2025 by The EH Angle Education and Research Foundation, Inc.)