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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]

Copyright of Dental Press Journal of 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.)

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 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.

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.

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]

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.)

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]

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]

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.

Copyright of Kieferorthopädie: die Zeitschrift für die Praxis is the property of Quintessenz Verlags GmbH 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.)

BackgroundMini-implant-assisted rapid palatal expansion (MARPE) appliances have been developed with the aim to enhance the orthopedic effect induced by rapid maxillary expansion (RME). Maxillary Skeletal Expander (MSE) is a particular type of MARPE appliance characterized by the presence of four mini-implants positioned in the posterior part of the palate with bi-cortical engagement. The aim of the present study is to evaluate the MSE effects on the midpalatal and pterygopalatine sutures in late adolescents, using high-resolution CBCT. Specific aims are to define the magnitude and sagittal parallelism of midpalatal suture opening, to measure the extent of transverse asymmetry of split, and to illustrate the possibility of splitting the pterygopalatine suture.MethodsFifteen subjects (mean age of 17.2 years; range, 13.9-26.2 years) were treated with MSE. Pre- and post-treatment CBCT exams were taken and superimposed. A novel methodology based on three new reference planes was utilized to analyze the sutural changes. Parameters were compared from pre- to post-treatment and between genders non-parametrically using the Wilcoxon sign rank test. For the frequency of openings in the lower part of the pterygopalatine suture, the Fisher's exact test was used.ResultsRegarding the magnitude of midpalatal suture opening, the split at anterior nasal spine (ANS) and at posterior nasal spine (PNS) was 4.8 and 4.3 mm, respectively. The amount of split at PNS was 90% of that at ANS, showing that the opening of the midpalatal suture was almost perfectly parallel antero-posteriorly. On average, one half of the anterior nasal spine (ANS) moved more than the contralateral one by 1.1 mm. Openings between the lateral and medial plates of the pterygoid process were detectable in 53% of the sutures (P

There is a critical need for an accurate device for orthodontists to know the magnitude of forces exerted on the tooth by the orthodontic brackets. Here, we propose a new orthodontic force measurement principle to detect the deformation of the elastic semi-sphere sensor. Specifically, we aimed to detail technical issues and the feasibility of the sensor performance attached to the inner surface of the orthodontic aligner or on the tooth surface. Accurate force tracking is important for the optimal decision of aligner replacement and cost reduction. A finite element (FE) model of the semi-sphere sensor was developed, and the relationship between the force and the contact area change was investigated. The prototype was manufactured, and the force detection performance was experimentally verified. In the experiment, the semi-sphere sensor was manufactured using thermoplastic polymer, and a high-precision mold sized 3 mm in diameter. The change in the contact area in the semi-sphere sensor was captured using a portable microscope. Further development is justified, and future implementation of the proposed sensor would be an array of multiple semi-sphere sensors in different locations for directional orthodontic force detection. [ABSTRACT FROM AUTHOR]

Introduction: Although with increasing popularity due to aesthetic appeal and comfort, clear aligners (CAs) are facing challenges in efficacy and predictability. Advancement in the underlying biomechanical field is crucial to addressing these challenges. This paper endeavors to provide a comprehensive framework for understanding the biomechanics of CA and enlightening biomechanics-based improvements on treatment strategies., Methods: A thorough review of the English-language literature accessible through PubMed and Google Scholar, without any publication year restrictions, was undertaken to unravel the biomechanical aspects of CA., Results: This review presented an up-to-date understanding of aligner biomechanics arranged by the framework of the material-dependent mechanical characteristics of CA, the geometric characteristics-dependent force transmission of the CA system, methods for studying the biomechanics of CA, and the biomechanical analyses for different types of tooth movement., Conclusions: Biomechanics should be the fundamental concern for concepts, methods and adjuncts attempting to enhance the accuracy and predictability of tooth movement induced by CA. Improvement on material properties and alteration of geometric design of CA are two main approaches to develop biomechanically optimized force system. Exploration of real-world force sensing and monitoring system would make substantial progresses in aligner biomechanics., Competing Interests: Declarations Ethics approval and consent to participate Not applicable. Consent for publication Not applicable. Competing interests The authors declared no competing interests., (© 2024. The Author(s).)

Objective: The use of clear aligners (CAs) for orthodontic treatment has substantially increased in recent decades. However, limited empirical evidence exists regarding their potential effects on the temporomandibular joint (TMJ). The aim of this study was to assess the effect of maxillary molar distalization on the positional and dimensional TMJ parameters between CAs and conventional fixed orthodontic appliances (FAs) in skeletal class II malocclusion., Methods: This is a retrospective cohort study examined 70 adult patients with skeletal class II malocclusion with similar baseline characteristics based on American Board of Orthodontics (ABO) discrepancy index scores. The patients were treated by maxillary distalization movement by CAs or FAs, of which there were two equal groups of 35 patients were included in each group. CBCTs on TMJs were performed before and after treatment through Anatomage Invivo Dental 6.0. The measured parameters included inclination, position, condyle and articular fossa dimensions, and the volumetric joint spaces., Results: In both groups, linear measurements of the maxillary molar position revealed significant improvement after treatment (P < 0.001). Regarding TMJ parameters, intra-group comparisons revealed significant changes in FA group in the anterioposterior condylar inclination and condylar position across the three planes. Additionally, the pretreatment-centric condylar position in the glenoid fossa was 45.7% and 40% in the CA and FA groups, respectively. After treatment, these percentages changed to 51.4% and 31.4%, respectively. In inter-group comparisons, significant changes were noted in the mediolateral condylar position, which was more inward in the FA group than the CA group., Conclusion: The FA group had more significant dimensional and positional changes in the mandibular condyle than the CA group; nevertheless, the changes are considered clinically negligible., Competing Interests: Declarations Ethics approval and consent to participate This retrospective cohort study was reviewed and approved by the Regional Review Board of China Medical University Stomatological Hospital, Shenyang, Liaoning, China (registration no. CMUKQ-2022-059) and also met the ethical principles of the World Medical Association Declaration of Helsinki. All participants provided informed consent to participate in the study. Consent for publication Not applicable. Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Lingual orthodontic technology has been in existence for over 50 years, undergoing various stages of emergence, development, decline, and maturity. In recent years, with the advancement of digital technology, customized lingual orthodontics has gradually become widely used in clinical practice, representing a significant achievement of digital technology in orthodontic clinical diagnosis and treatment. The integration of digital technology has made customized lingual orthodontics more convenient, precise, and efficient, enhancing patient comfort while significantly reducing the operational difficulty and technical barriers for orthodontists. This article focuses on analyzing the technical characteristics, operational challenges, and coping strategies of customized lingual orthodontics based on digital technology, aiming to provide a reference for clinical practice.

With the advancement of digital healthcare and artificial intelligence (AI) technologies, the full automation of clear aligner orthodontic technology has become feasible. Significant research findings and commercial applications have emerged in areas such as intelligent diagnosis of multimodal orthodontic data, orthodontic treatment decision-making, automated generation of digital treatment plans, and remote intelligent monitoring. However, in the development and application of AI software, it is imperative to address issues related to clinical risks, target populations, and compliance with medical device software regulations. This article analyzes and summarizes the applications and challenges of AI in clear aligner orthodontic diagnosis, treatment, and production processes. Furthermore, it explores potential future trends in this field, providing valuable insights for clinical reference.

Objectives: To compare effectiveness of two protocols for correcting deep bite in growing patients using a removable anterior bite plane (RABP): full-time wear with appliance on during meals (F + M) vs off during meals (F - M) and to explore the relationship between average daily duration of wear and overbite (OB) correction rate, stratified by the wear protocol., Materials and Methods: Thirty-two growing patients with deep bite (mean age = 10.94 ± 2.17 years) were randomly assigned to the F + M (n = 16) or F - M (n = 16) group. Cephalometric radiographs were taken at baseline (T0) and when normal OB was achieved (T1). Duration of wear was recorded by a TheraMon microsensor within the appliance. A best-fit regression model for the relationship between daily duration of wear and OB correction rate was determined (α = 0.05)., Results: Both groups exhibited similar baseline characteristics and cephalometric changes, ie, molar extrusion, and incisor intrusion and proclination in both arches (P < .05), and intergroup differences were not significant. Here, F + M exhibited significantly faster rates of deep bite correction (1.83 ± 1.18 vs 1.08 ± 0.62 mm/month; P < .05) and mandibular molar extrusion (0.46 ± 0.25 vs 0.30 ± 0.18 mm/month, P < .05) compared with F - M. Best-fit regression models for relationship between daily duration of wear and OB correction rate were exponential for both F + M (R2 = 0.53) and F - M (R2 = 0.74)., Conclusions: Here, F + M and F - M protocols resulted in comparable cephalometric changes among deep bite growing patients. However, the F + M group exhibited a faster correction rate. Daily duration of wear positively correlated with OB correction rate in an exponential manner., (© 2024 by The EH Angle Education and Research Foundation, Inc.)

Objectives: To evaluate the impact of printer technology and print orientation on the accuracy of directly printed retainers., Materials and Methods: Digital retainers were printed with two different printing technologies: digital light processing (DLP) and stereolithography (SLA), using two different orientations: 0° and 90°. After printing, the retainers (n = 40) were scanned using cone-beam computed tomography. The DICOM files were then converted into standard tessellation language (STL) files. Comparison of the printed retainers with a master file was done by superimposition using a three-dimensional (3D) best-fit tool in Geomagic software. A ±0.25 mm tolerance was set to detect differences between the superimposed files. Statistical analysis was conducted (Kruskal-Wallis and Wilcoxon-Mann-Whitney tests, with Bonferroni correction)., Results: The lowest median average deviation was observed for the DLP horizontally printed models (median, [interquartile range (IQR)] = 0.01 mm, [-0.01, 0.02]) followed by the SLA horizontally printed retainers (median, [IQR] = 0.05 mm, [0.03, 0.07]). The highest median inside the tolerance levels ratio was observed for the horizontally SLA printed retainers (median, [IQR] = 78.9%, [74.4, 82.4%]) followed by the horizontally DLP printed retainers (median, [IQR] = 78.2%, [74.5, 80.7%])., Conclusions: Both technologies (DLP and SLA) showed 3D printed results compatible with orthodontic clinical needs. Printing orientation was more important than printer type regarding its accuracy. Additional studies are needed to evaluate the accuracy of direct printed appliances clinically., (© 2024 by The EH Angle Education and Research Foundation, Inc.)

Objectives: To compare the transfer accuracy of two different indirect bonding (IDB) trays., Materials and Methods: Digital IDB was performed on a total of 30 patients using one of two designs: shell and bar trays, with 15 patients in each group. Trays were designed with the Appliance Designer software (3Shape A/S, Copenhagen, Denmark). Angular (torque, tip, angulation) and linear (mesiodistal, buccolingual, occlusogingival) differences were compared between the bonded intraoral scans taken immediately after IDB and the virtually bracketed model prepared in Ortho Analyzer software (3Shape A/S) using open source GOM inspect software (GOM GmbH, Braunschweig, Germany)., Results: There were no significant differences found between the bar and shell groups. Within the groups, significant tip differences were found between the incisors, canines, and premolars in both groups (P = .0001). Additionally, a statistically significant torque difference was found in the canines and incisors in the shell group. The percentage of values that deviated from the clinical acceptance limit was relatively higher in the bar group., Conclusions: Although there was no statistical difference between groups, the shell tray showed better results according to clinical acceptability limits. This study is important as it is the first clinical study to compare directly printed transfer trays with different designs., (© 2024 by The EH Angle Education and Research Foundation, Inc.)

Objectives: To compare the effect of clear twin block (CTB) and traditional twin block (TTB) appliances on speech., Materials and Methods: In this randomized clinical trial, 18 skeletal Class II (Class II, division 1) growing patients were selected and randomly divided into CTB and TTB groups. Objective and semiobjective speech assessment tests were performed for vowel and consonant analyses at four time intervals: before (T0), immediately after (T1), 1 month after (T2), and 3 months after (T3) inserting the appliance. Data were analyzed using analysis of variance and independent t-test at the .05 significance level., Results: Intergroup comparisons showed that the CTB group had less speech distortion immediately after insertion of the appliance (P < .05) than the TTB group; however, the differences were not significant at other time intervals. Intragroup comparisons showed that the number of distortions decreased significantly from T1 to T3 in both groups (P < .05). In contrast to CTB, the T0-T3 comparison was significant in the TTB group., Conclusions: Although both appliances had some effects on speech, CTB had less speech distortion immediately after insertion, which is a very crucial moment in patient compliance. Additionally, articulation structures adapted to CTB faster than to TTB., (© 2024 by The EH Angle Education and Research Foundation, Inc.)

Introduction: 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., Methods: Mesialization of the mandibular second molar with clear aligner treatment was simulated using the AlGOR Fempro program (ALGOR, Inc, Pa) with 3 different configurations., Results: 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., Conclusions: 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., (Copyright © 2024 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: This prospective study compared pain perception, intensity, and analgesic use among patients treated with fixed appliances (FAs) and clear aligners (CAs) over 6 months., Methods: Digital surveys were collected from 87 adult patients treated with CA or FA from 2 orthodontic offices. The 7-item survey was sent at 3-time points (preappointment, 2-day postappointment, and 7-day postappointment) for each appointment. Wilcoxon, t test, and Fisher exact chi-square tests were performed with significance set at 0.05., Results: The FA group had a higher rate and intensity of pain 2 days after the second, third, and fifth appointments (P <0.030). At 7 days postappointment, the FA group had a higher rate and intensity of pain for the first and fifth appointments. Dull pain was reported the most in both groups, with a proportion of FA patients reporting throbbing (31%) or sharp (20%) pain (P = 0.035) at 2 days postappointment. The CA group reported the most pain at rest, whereas the FA group reported chewing as the most painful (P = 0.002). The FA group had a higher rate of analgesic consumption after the first appointment (P = 0.037)., Conclusions: Both the FA and CA groups experienced similar rates and intensities of pain 2 days after the delivery of appliances at the first appointment. Although CA pain intensity remained minimal, FA pain peaked 2 days postappointment whenever a new orthodontic stimulus was introduced and remained elevated 7 days postappointment when that stimulus was a new archwire material., (Copyright © 2024 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.)

We demonstrate pre-epiglottic baton plate as non-invasive treatment modality for initial airway management in newborns with Pierre Robin Sequence. A case example illustrates management of upper airway obstruction and feeding using digital technology to facilitate customization. Laryngoscope, 134:4766-4769, 2024., (© 2024 The Authors. The Laryngoscope published by Wiley Periodicals LLC on behalf of The American Laryngological, Rhinological and Otological Society, Inc.)

Introduction: This study aimed to analyze the load-deflection characteristics of an orthodontic cantilever by using the large deflection elastic model., Methods: We experimentally measured the vertical deflections of a cantilever with round or rectangular cross-sections, with lengths of 20 mm and 30 mm, and made of either stainless steel or titanium molybdenum alloy. The measurements were obtained under clinically relevant loading ranges (20-60 g of force for round and 20-140 g of force for rectangular wires) and compared with theoretical predictions derived from small and large deflection elastic models. Load-deflection and tangent stiffness curves were subsequently plotted., Results: The impact of a permanent deformation was clinically insignificant. The stiffness of the cantilever increased with the load or deflection rather than remaining constant. Within the clinical loading range, we identified stiffness reversal loading values at which the stiffness of titanium molybdenum alloy surpassed that of stainless steel. The textbook guidelines on cantilevers can apply only when the vertical deflection remains within 16% of its length., Conclusions: Within the typical clinical loading range, the load-deflection relationship of a cantilever deviates from Hooke's law because of the prominent deflection trait. The conventional model remains effective when the vertical deflection is within 16% of the cantilever length. Otherwise, it is advisable to determine the load and stiffness on the basis of actual measurements rather than relying on theoretical predictions., (Copyright © 2024 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.)

Objective: The mandibular advancement device (MAD) is currently suggested in patients with mild to moderate obstructive sleep apnea (OSA). This study investigated the effects of a new fully customizable MAD-type device called, "It Makes You Sleep" (IMYS), in patients with mild to moderate OSA., Methods: Sixteen patients (14 men and 2 women; mean age 62; SD ± 11 years) were retrospectively enrolled. Each patient received home sleep apnea testing (HSAT) at baseline (T0) and after three months (T1) of IMYS treatment. The Apnea-Hypopnea Index (AHI), the Oxygen Desaturation Index (ODI), the Minimum Oxygen Saturation (minSO2) and the Medium Oxygen Saturation (medSO2) were analyzed., Results: From T0 to T1, the IMYS treatment showed a significant reduction of AHI and ODI and a significant increase of minSO2 and medSO2., Conclusion: The IMYS appliance is an effective device for treating mild or moderate OSA.

Purpose: To investigate the skeletal and dental effects of a hybrid fixed functional appliance (FFA) used with different force magnitudes for class II subdivision 1 treatment., Methods: Treatment records from 70 patients were evaluated: 35 patients were treated with a FFA with standard activation (SUS group) and 35 with a FFA with an additional force-generating spring (TSUS group). Two control groups were matched from the American Association of Orthodontists Foundation (AAOF) Craniofacial Growth Legacy Collection for comparison with the two treatment groups to determine skeletal and dental treatment effects. The cephalometric parameters at T0 (before treatment) and T1 (before debonding) were assessed using the Munich standard cephalometric analysis and by the sagittal occlusal analysis (SO) according to Pancherz. Data were analyzed statistically using SPSS., Results: No statistically significant difference for any cephalometric parameter was observed between the SUS and TSUS groups concerning the measurements at T0 and T1. Both treatment groups exhibited an effective class II therapy mainly due to a significant reduction in SNA, and ANB and an increase in SNB. In contrast to the control group, as the result of treatment a skeletal class I was achieved., Conclusion: No significant statistical differences were observed between the patient group treated with the FFA with standard activation (SUS) and those treated with an additional spring (TSUS) regarding the cephalometric parameters investigated. Both variants were equally effective in treating class II division 1 malocclusions., (© 2023. The Author(s).)

Objectives: The Functional Clear Aligner (FCA) is a novel orthodontic appliance designed for the treatment of Class II malocclusion with mandibular retrognathia in adolescents. The aim of this study was to investigate the biomechanical characteristics of the masticatory muscles, jawbone, and temporomandibular joint (TMJ) during mandibular advancement using either FCA or Class II elastics combined with clear aligner (Class II elastics) through finite element analysis., Materials and Methods: A 3D finite element model of the 'muscle-jawbone-TMJ-appliance' system was constructed based on CBCT and MRI images of a boy with skeletal Class II malocclusion. Masticatory muscles included masseter, temporal, medial pterygoid, and lateral pterygoid muscles. The TMJ consists of the temporal bone's glenoid fossa, disc, and mandibular condyle. To observe the biomechanical characteristics of the muscles and TMJ during orthodontic appliance wearing and the retention phase, two different protocols were used: Model 1: The mandibular advancement using FCA; Model 2: The mandibular advancement using Class II elastics., Results: The FCA group produced greater and more coordinated masticatory muscle forces compared to the Class II elastics group. Temporal and masseter muscles exhibited the most pronounced variation in muscle strength during mandibular advancement. The FCA group exhibited greater TMJ region stress compared to the Class II elastics group. Interestingly, the stress on the articular discs in both models decreased over time. Tensile stresses were observed in both the condyle and the posterior region of the articular fossa., Conclusion: During skeletal Class II malocclusion treatment, masticatory muscle forces and stress on the TMJ were higher in the FCA group compared to the Class II elastics group. In both models, stress cushioning was provided by the articular disc., (© 2024. The Author(s).)

Objective: To compare the levels of functional impairments, discomfort and satisfaction experienced by those treated with full-mouth customized lingual appliances (Lingual appliances), full-mouth self-ligating bracket (Labial appliances), or upper lingual and lower labial appliances (Mixed appliances) using questionnaires., Materials and Methods: Patients within one year of the end of treatment were included in the survey and given a questionnaire concerning different kinds of discomfort and difficulties during the treatment process. The questionnaires focused on the following aspects including speech difficulty, pain (lip, cheek or tongue), difficulty in chewing, difficulty in tooth brushing and overall aesthetics and comfortability. Ordinary one-way ANOVA Tukey's multiple comparison tests and Kruskal-Wallis tests were employed to analyze the data., Results: A total of 115 patients participated in the study. In terms of functional impairments and discomfort, the rate and degree of speech difficulty was significantly higher in the Lingual appliances Group than that in the Labial appliances Group. But there was no difference among the three groups for difficulty in chewing and tooth brushing. Both lingual and labial appliances caused a similar level of overall pain, however, those treated with lingual appliances experienced more tongue pain, and those treated with labial appliances experienced more cheek and lip pain. The most common sites of irritation were the tongue lateral and tongue tip in the Lingual appliances Group, tongue lateral and cheek in the Mixed appliances Group, and cheek and lower lip in the Labial appliances Group. In total, patients gave highest scores to mixed appliances for comfortability and lowest scores to labial appliances for aesthetics when it came to satisfaction., Conclusions: Lingual and labial appliances caused similar level of overall pain. Taking into account the overall comfortability, aesthetics and cost, the mixed appliances may be suitable for some patients who have aesthetic and comfort pursuits., (© 2024. The Author(s).)

Purpose: This study aimed to compare the acceptability of removable acrylic appliances (RA) and Invisalign First (IF) clear aligners (Aligntech, USA) among children undergoing orthodontic treatment during the mixed dentition period, considering the severity of malocclusions., Methods: A total of 40 patients, aged 6 to 13 years, were recruited for the study. Malocclusion severity was evaluated using the Index of Orthodontic Treatment Need-Dental Health Component (IOTN-DHC). Patients completed the "Acceptance of Orthodontic Appliance Scale (AOAS)" via a face-to-face Google survey. To assess the reliability of the AOAS, the survey was resent to five patients after three months for a second response, and reliability analysis was conducted. Additionally, inter-rater reliability was evaluated by having all patients independently assessed by a second researcher. Data were analyzed using SPSS Statistics version 26 (IBM Corp., Armonk, NY, USA), with statistical significance set at p < 0.05., Results: Although no significant difference was found in IOTN-DHC scores, the IF group demonstrated significantly higher AOAS scores compared to the RA group (p = 0.014). Survey responses revealed noticeable distinctions between groups regarding speaking discomfort, preference for orthodontic appliances, and facial appearance comfort. A negative correlation (r = -0.477, p = 0.034) was observed between malocclusion severity and appliance acceptance., Clinical Significance: This study underscores the significant superiority and advantage of IF over RA among pediatric orthodontic patients during the mixed dentition period., (© 2024. The Author(s).)

Background: Prosthetically guided orthodontics (PGO) can correct the malocclusion for better prosthetic rehabilitation in esthetic rehabilitation. Unlike conventional orthodontic treatment, only minor tooth movement is designed in PGO according to the requirement of subsequent restoration. For better appearance during the treatment, PGO is often performed with clear aligners, which have no metal brackets. It has been proven that the PGO with clear aligners can achieve generally satisfactory outcomes. However, its risk has not been fully known due to the paucity of relevant studies., Case Presentation: Three patients who needed esthetic rehabilitation with mild malocclusion were included in this study. After evaluation, a prosthetic solution alone was considered insufficient to provide optimal outcomes. Thus, they were treated using PGO with clear aligners (Invisalign Go, Align Technology, Santa Clara, California, USA) and accomplished prosthetic rehabilitation subsequently. Dental history and X-ray examination revealed that endodontically treated teeth (ETT) existed in all the cases. Intraoral photographs were collected to compare the pre-treatment and post-treatment dentition. After PGO, posterior ETT did not maintain their position as scheduled and lost occlusal contacts, while all the anterior teeth, including anterior ETT, were moved to the designed position. Corresponding prosthetic rehabilitation was used to solve it after consulting with the patients., Conclusions: Occlusal contact loss of posterior ETT is a potential risk in PGO with clear aligners, affecting the orthodontic result., (© 2024. The Author(s).)

Objective: The aim was to assess adult patients' weight changes during the initial phase of orthodontic treatment (OT) with clear aligner therapy (CAT) versus fixed bracket systems (FBS)., Methods: This pilot prospective cohort study included systemically-healthy adults who were treated with CAT or FBS. Participants with eating disorders and/or undergoing dietary programs were excluded. Weight was assessed using a calibrated digital scale at the start of OT (T1), 6-8 weeks (T2), and 12-16 weeks (T3) after starting OT. A questionnaire was used to record demographic variables, diet and exercise habits, self-reported compliance and discomfort during OT, and use of analgesics. Repeated measures analysis of variance was used to assess the association between treatment type (FBS versus CT) and time-period (T1, T2, T3) on participants' weight while adjusting for baseline covariates such as age, gender, height, and weight., Results: Forty-two participants (CAT group: 22 and FBS group: 20) were analysed. In the CAT group, there was a slight initial mean weight gain of 0.2 Kg (~ 0.4 pounds) (T2-T1), and 0.8 Kg (~ 1.7 pounds) overall mean weight loss between T1 and T3. For the FBS group, there was a slight initial weight loss of 0.3 Kg (~ 0.7 pounds) (T2-T1) and no overall change between T1 and T3. Treatment type (CAT versus FBS) was not significantly associated with weight changes during the initial phase of OT., Conclusions: There were no significant differences in the weight changes during the initial phase of OT with CAT compared with FBS., Clinical Relevance: Clear aligner therapy should not be advertised as a weight loss strategy., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: The aim of the investigation was to evaluate if the inclination of the lower anterior teeth can be controlled reliably after lower premolar extraction for Class III camouflage treatment with completely customized lingual appliances (CCLAs). Treatment outcome was tested against the null hypothesis that lower premolar extractions for non-surgical camouflage treatment of a Class III malocclusion will lead to further compensation by retroclining mandibular incisors during CCLA treatment., Methods: This retrospective study included 25 patients (f/m 12/13; mean age 20.7 years, SD 9.5 years) with uni- or bilateral Class III molar relationship and a Wits value of ≤ -2 mm. In all consecutively debonded patients, lower premolars were extracted to correct the sagittal relationship with a non-surgical camouflage approach. Lateral head films prior to (T1) and at the end of lingual orthodontic treatment (T2) were used to evaluate skeletal and dentoalveolar effects. A paired t-test with alpha = 5% was used to define differences between the endpoints. The linear correlation between the inclination of the mandibular incisors at T1 and the achieved correction was measured with the Pearson correlation coefficient (PCC). A Schuirmann's TOST equivalence test was used to check if the final lower incisor inclination was within the defined norms., Results: The null hypothesis was rejected as the mean lower incisor inclination was improved by 1.8° despite lower premolar extractions (T1: 86.8°/ T2: 88.6°). There was a strong correlation (-0.75) between the lower incisor inclination at T1 and the achieved correction indicating a controlled correction towards the norm regardless of the initial incisor position. At T2, the interincisal angle as well as the lower incisor inclination were within the norm., Conclusion: Lower premolar extractions for non-surgical camouflage treatment of a Class III malocclusion will not lead to undesired retroclining of mandibular incisors during CCLA treatment even in severe cases., (© 2024. The Author(s).)

Background: Extracting the premolars is an effective strategy for patients with bimaxillary dentoalveolar protrusion. Clear aligners (CAs) close the extraction spaces through shortening the length of aligners. The contraction force generated by the terminal of aligners makes the posterior teeth tip mesially, which is known as the roller coaster effect. This phenomenon is even worse in the 2nd premolar extraction cases. Posterior anchorage preparation is commonly used to protect the angulation of molars, taking the form of presetting distal tipping value. However, the distal tipping design aggravates the anchorage loss of anterior teeth simultaneously. This study aimed to explore the different anchorage loss of the posterior teeth when the 1st or 2nd premolars were extracted using CAs, respectively in maxillary and mandibular arches, further providing guidance for anchorage preparation design in clinical practice., Methods: Two bimaxillary finite element models with different extraction patterns were established to simulate the anterior en-masse retraction process of the CAs. In Model 1, the maxillary and mandibular 1st premolars were extracted, while in Model 2, the 2nd premolars were extracted. Finite element analysis methods were utilized to analyze the tipping angle of the anterior and posterior teeth., Results: Compared between two models, the anterior teeth exhibited a greater lingual inclination tendency and the posterior teeth exhibited a slighter mesial tipping tendency in Model 1 regarding individual tooth. The closer to the extraction spaces, the greater the tip, and the distal tipping tendency of the 1st premolars was more evident than the mesial tipping tendency of the 1st molars in Model 2. Compared between the maxillary and mandibular arches, the mesial tipping tendency of individual posterior tooth was more evident in the maxilla. In addition, the highest hydrostatic stress of the periodontal ligaments was concentrated on the cervical and apical parts directly adjacent to the extraction spaces, and it exhibited relatively uniform distribution in Model 1., Conclusions: The individual posterior tooth showed the same mesial tipping direction but to different degree when the 1st or the 2nd premolars were extracted during clear aligner treatment. Presetting anchorage preparation design for the posterior teeth is essential to alleviate the roller coaster effect, especially in the 2nd premolar extraction cases. Furthermore, larger anchorage preparation value should be proposed for the maxillary posterior teeth., (© 2024. The Author(s).)

Objectives: Occlusal splints are the main therapeutic choice in the treatment of temporomandibular disorders (TMD). However, their precise working mechanism is unclear. This study aimed to compare the biomechanical effect of three commercially available splint designs (full covering splint, anterior bite splint and posterior bite splint) during biting in a sample of healthy subjects., Materials and Methods: Magnetic resonance imaging (MRI) was combined with jaw tracking to measure the minimal intraarticular distance (MID) of 20 human temporomandibular joints (TMJ) whilst simultaneously recording the electromyogram (EMG) of the masticatory muscles. The changes caused by clenching with a bite force of 100 N without splint (baseline) and on each splint were calculated. Repeated measures ANOVA was performed on the means of the MID variations and EMG amplitudes., Results: Clenching on the anterior bite splint resulted in two times less activation of the anterior temporalis muscle than baseline (p = 0.003), full covering (p = 0.011) and posterior bite splint (p = 0.011). MID was reduced by clenching in all conditions, but the reduction was almost three times larger with the anterior bite splint compared to no splint (p = 0.011). The full covering splint and the posterior bite splint did not differ significantly in EMG activation of both masseter and temporalis muscles and MID variation., Conclusions: This study showed that splint designs have a different impact on the MID and EMG activation while clenching. The anterior bite splint had a greater impact on the reduction of the muscle activation, whereas clenching on the anterior bite splint led to bigger reduction of MID and thus had the greatest influence on alteration in the condylar position., Clinical Relevance: The design of the splint can affect MID and muscle activation and is a variable to consider in the treatment of patients with TMD according to their symptoms., (© 2024. The Author(s).)

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

Introduction: Patients with Class II, division 1 malocclusion generally seek treatment to improve facial esthetics. Therefore, the orthodontist needs to know the changes in the soft profile produced by functional appliances., Objective: This study evaluated the soft tissue profile changes in patients treated during the peak of the pubertal growth spurt., Methods: Thirty selected patients were randomized into three treatment groups: Twin Block (TB), Herbst with dental anchorage (HDA), and Herbst with skeletal anchorage (HSA). All patients had computed tomographic images: pretreatment (T1) and after 12 months of active treatment (T2). Twenty-four soft tissue cephalometric measures were analyzed. The normality of all data was assessed by the Shapiro-Wilk test. Intragroup comparisons were analyzed using the t-paired test; the inter-group comparisons were determined through ANOVA and the post-hoc Tukey test., Results: At T1, no significant differences were observed between groups. At T2, in the intragroup comparison, facial soft tissue changes were statistically significant in the three groups for the lower lip, sulcus inferioris, facial soft tissue convexity in HDA group and TB group, and H angle in HDA group and HSA group, and soft tissue pogonium in TB group. In the inter-group comparison, no statistically significant differences were observed., Conclusion: It can be concluded that there were significant changes in soft tissue measurements that benefited Class II, division 1 patient's facial profile treated with the functional appliances Twin Block, Herbst, and Herbst with skeletal anchorage. Nevertheless, no significant differences were detected among the effects obtained by the three treatment protocols.

Objective: This study evaluated the force system generated by the Memory Titanol® spring (MTS) with different preactivation bends using an orthodontic force tester (OFT)., Methods: Three preactivations were tested using a 0.017 × 0.022-in stainless steel (SS) wire and a 0.018 × 0.025-in NiTi segment, with an activation of 30º in the posterior segment (β), with 0º (Group 1 [G1]), 45º (Group 2 [G2]), and 60º (Group 3 [G3]) in the anterior segment (α)., Results: The molars showed extrusion values of -1.33 N for G1 and -0.78 N for G2, and an intrusion value of 0.33 N for G3. The force in the premolars was intrusive with a variation of 1.34 N for G1 and 0.77 N for G2; and extrusive with a variation of -0.31 N for G3. Regarding the upright moment (Ty) of the molar, a distal moment was observed with values of 53.45 N.mm for G1 and 19.87 N.mm for G2, while G3 presented a mesial moment of -6.23 N.mm. G1, G2, and G3 all exhibited distal premolar moments (Ty) of 3.58, 2.45, and 0.68 N.mm, respectively., Conclusions: The tested preactivations exerted an extrusive force in G1 and G2 and an intrusive force in G3 during molar vertical movement. The premolar region in G1 and G2 showed intrusive force and distal moment.

Objectives: This study aimed to compare treatment efficacy and cephalometric outcomes between extraction and non-extraction MEAW therapies in non-growing open-bite patients., Materials and Methods: 22 Multiloop Edgewise Archwire MEAW patients (11 males, 11 females) and 15 bicuspid extraction patients (3 males, 12 females) were selected according to a strict inclusion criterion. Comprehensive data collection related to age, sex, Cervical Vertebral Maturation CVM staging, and severity of the Anterior Open Bite AOB (1 = 0-1 mm; 2 = 1-2 mm; 3 = > 2.1 mm) was performed independently and in duplicate by 2 examiners. Each included patient's pre and post-treatment lateral cephalograms were traced and compared. The primary outcomes assessed were related to the efficacy of treatment: treatment duration and time needed to achieve a positive overbite. The secondary outcomes assessed were related to the post-treatment changes in cephalometric measurements between the groups. Descriptive statistics, Mann-Whitney U test, unpaired student's t-test, and Chi-squared were used for data analysis., Results: The mean change in open bite closure was 3.07 ± 2.07 mm in the MEAW group and 3.03 ± 2.28 mm in the extraction group (P > 0.05). MEAW therapy was 31% faster (118 weeks) than extraction therapy (171 weeks, P = 0.004). MEAW appliance showed a significantly shorter duration for open bite closure (71.82 ± 29.57 weeks) compared to the extraction group (127.25 ± 51.97 weeks, P = 0.002). A greater decrease in the U1-SN was seen in the extraction group (-8.70 ± 6.49°), compared to the MEAW group (-2.56 ± 7.36°, P = 0.047). The IMPA angle showed a greater decrease in the extraction group (-8.30 ± 8.85°) compared to the MEAW group (-0.90 ± 6.50°, P = 0.032). The (L6-MP perp) increased in the extraction group by (1.98 ± 3.43 mm), while decreased in the MEAW group (-0.43 ± 1.38 mm, P = 0.023)., Conclusion: In anterior open bite cases with bicuspid extraction, achieving a positive overbite typically involves retroclining and uprighting the upper and lower incisors (drawbridge effect). In contrast, the MEAW appliance focuses on uprighting the entire dentition and intruding the posterior teeth, often leading to shorter treatment durations., Clinical Relevance: The MEAW appliance's biomechanical advantage in uprighting posterior teeth in open bite cases may shorten treatment duration for correcting open bite malocclusion., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Retainers have the potential to detrimentally impact periodontal health and contribute to tooth decay., Objectives: To investigate periodontal health and bacterial biofilm related to Poly-Ether-Ether-Ketone (PEEK) fixed retainers as compared to Dead-soft coaxial fixed retainer (DSC)., Trial Design: A two-arm parallel groups single-centre randomized clinical trial., Methods: The trial included patients whose orthodontic treatment was completed and required retainers. Participants were randomly assigned into two retainer groups: PEEK retainers, prepared by computer-aided design and manufacturing into 0.8 mm wire form, and DSC retainers. The objectives included assessing periodontal health through plaque accumulation index (PI), bleeding on probing (BOP), periodontal pocket depth (PPD), gingival index (GI), calculus index (CI), and alveolar bone height (ABH) assessment. Biofilm assessment involved bacteriological screening of aerobic, facultative anaerobic, mutans streptococci, and lactobacilli. The periodontal indices and microbiological screening as well as were assessed at the debonding stage (T0), 1-month (T1), 3-month (T3), and 6-month (T6) after the commencement of the trial, except for the ABH, which was recorded using periapical radiograph at T0 and T6., Blinding: Single blinding of participants in addition to the bacteriological specialist., Results: Initially, the trial enrolled 46 participants, aged between 12 and 28 years, and were randomly assigned to two groups, with 23 participants in each group. Subsequently, one participant withdrew from the trial, resulting in a total of 45 participants whose data were analysed. Assessment of the periodontal indices, excluding the CI (P = .480), revealed statistically but not clinically significant differences between groups after 6-month of retention (P = .016 of PI, P = .020 of BOP, P = .05 of PPD, and P = .01 of GI). There was slight plaque accumulation, normal PPD (approximately 1 mm), healthy to mild gingivitis with a GI of less than 1 and BOP was around 10%. Concerning the ABH, there was a noticeable reduction in its score after 6 months, particularly in the PEEK group, although the difference was not statistically significant (P = .102). Furthermore, the bacteriological viable count did not show any significant difference between the groups during the recall visits., Harms: There have been no reported negative consequences., Limitations: Blinding the assessor of periodontal indices was not feasible due to the nature of the intervention. The trial follow-up duration was limited., Conclusions: Both the PEEK and DSC retainers have comparable impacts on periodontal health and bacterial accumulation and composition during the retention period., Trial Registration: NCT05557136., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Aim: To investigate the post-treatment (Tx) changes (≥ 15 years) in adult Class II patients treated with Herbst appliance and subsequently a multibracket appliance (MBA)., Subjects and Methods: Of 51 potential patients 31 could be located and participated (19 II:1 and 12 II:2). At a mean age of 21.8 ± 7.3 years (T0), Herbst-MBA Tx had been started. The mean post-Tx observation period was 19.8 ± 3.6 years. Study models from before and after Tx (T1, mean age: 23.6 ± 7.4 years), after 3.0 ± 2.8 years of retention (T2, mean age: 26.8 ± 8.3 years) as well as after recall (T3, mean age: 43.4 ± 7.5 years) were evaluated using the PAR index as well as standard occlusal variables., Results: Pre-Tx, the mean values of the 31 participants were: PAR score = 26.1 ± 9.6 points, Class II molar relationship (MR) = 0.7 ± 0.2 cusp widths (CW), overjet = 6.9 ± 2.3 mm and overbite = 4.8 ± 2.6 mm. After Tx, the mean PAR score was 5.3 ± 2.8. A Class I MR (0.0 ± 0.1 CW) was present while overjet and overbite had decreased to 2.1 ± 0.7 and 1.3 ± 0.8 mm, respectively. At recall (19.8 ± 3.6 years post-Tx), a slight PAR score increase (+ 3.1 points) had occurred (final value: 8.4 ± 3.7); this was mainly due to mild increases in overjet, overbite (final values: 3.3 ± 1.4 mm and 2.5 ± 1.7 mm) and changes in sagittal MR (0.2 ± 0.2 CW)., Limitations: The sample size and the participation rate as well as the unavailability of a comparable control group can be considered as limitations. In addition, no long-term radiographic data could be obtained, and the retention protocol was not uniform. The majority of these issues, however, should be acceptable to due to the duration of the observation period and the uniqueness of the data., Conclusion: In the present sample, Herbst-MBA Tx enabled Class II correction in adults with very good occlusal long-term stability., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Background: Poly-ether-ether-ketone (PEEK) was introduced in dentistry as an alternative to metal alloys., Objective: To assess the effectiveness of PEEK-fixed retainers in preserving the stability of mandibular anterior and participant satisfaction as compared to the Dead-soft coaxial fixed retainer (DSC)., Trial Design: A single-centre, two-arm parallel groups randomized clinical trial., Methods: The patients treated with pre-adjusted orthodontic appliances who have a Little's Irregularity Index (LII) ≤ 0.5 mm have been enrolled in the trial. PEEK retainers were prepared to round 0.8 mm wire by computer-aided design and manufacturing, and the DSC wire was carefully adapted to the lingual surface of the lower anterior teeth. The primary outcome was the stability of lower anterior teeth as assessed by LII, while the secondary outcomes were changes in occlusal parameters, retainer failure, and patient satisfaction. The data were collected at the debonding stage (T0), 1 month (T1), 3 months (T3), and 6 months (T6) after starting the trial, except for patient's satisfaction, which was recorded using an electronic form at T1 and T6., Blinding: Single blinding of participants., Results: A total of 46 participants with an age range of 12-28 years old were randomly allocated to the two groups (n = 23 in each). Only one participant dropped out; therefore, 45 participants were analysed. The DSC group showed a significant increase in LII at T3. Both retainer groups had comparable occlusal measurements, failure frequency, and survival time, with no significant difference. The patients in the DSC group reported a statistically significant perception of change in the position of their teeth compared to those in the PEEK group., Harms: No harmful effects have been reported., Limitations: Limited follow-up duration and the inability to blind the operator due to the nature of the intervention., Conclusions: After 6-month retention, the PEEK retainer was equally effective to DSC retainers in maintaining the teeth alignment, with no significant differences regarding the failure frequency, survival rate, and general patient satisfaction., Trial Registration: https://register.clinicaltrials.gov. (NCT05557136)., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)