Effects of different intrusion patterns during anterior teeth retraction using clear aligners in extraction cases: an iterative finite element analysis.

Background: Overtreatment design of clear aligner treatment (CAT) in extraction cases is currently primarily based on the clinical experience of orthodontists and is not supported by robust evidence on the underlying biomechanics. This study aimed to investigate the biomechanical effects of overtreatment strategies involving different maxillary anterior teeth intrusion patterns during anterior teeth retraction by CAT in extraction cases. Materials and methods: A finite element model of the maxillary dentition with the first premolar extracted was constructed. A loading method of clear aligners (CAs) based on the initial state field was proposed. The iterative method was used to simulate the long-term orthodontic tooth movement under the mechanical load exerted by the CAs. Three groups of CAs were utilized for anterior teeth retraction (G0: control group; G1: incisors intrusion group; G2: anterior teeth intrusion group). Tooth displacement and occlusal plane rotation tendency were analyzed. Results: In G0, CAT caused lingual tipping and extrusion of the incisors, distal tipping and extrusion of the canines, mesial tipping, and intrusion of the posterior teeth. In G1, the incisors showed minimal extrusion, whereas the canines showed increased extrusion and distal tipping tendency. G2 showed the smallest degree of posterior occlusal plane angle rotation, while the inclination tendency of the canines and second premolars decreased. Conclusion: 1. In CAT, tooth displacement tendency may change with increased wear time. 2. During anterior teeth retraction, the incisor intrusion pattern can provide effective vertical control for the lateral incisors but has little effect on the central incisors. Anterior teeth intrusion patterns can alleviate the inclination of canines and second premolars, resulting in partial relief of the roller-coaster effect.

Guia prático de fabricação de alinhadores in-house ­ Parte 1: Introdução ao sistema / Practical guide to in-house aligner fabrication ­ Part 1: Introduction to the system

Resumo O uso de alinhadores para o tratamento das más oclusões tem, cada vez mais, despertado o interesse dos ortodontistas. Desde a sua apresentação no mercado, há pouco mais de duas décadas, os alinhadores vêm conquistando um importante espaço, muito em função das mudanças direcionais no exercício da especialidade, geradas pela demanda por tratamentos com uma abordagem estética e de maior conforto. Na prática, essa transformação impactou a gestão dos consultórios dos ortodontistas, habituados com o total controle sobre o fluxo de montagem e fabricação dos aparelhos convencionais. A contratação de empresas para a fabricação industrial dos alinhadores foi o conceito proposto originalmente pela Align Technology, fabricante do Invisalign, pioneira nesse sistema comercial e líder no mercado. Entretanto, em função dos custos inerentes a esse serviço, bem como das limitações temporais impostas pela terceirização, foi criado um fluxo digital de fabricação in-house dos alinhadores, pelos próprios ortodontistas. Diante dessa realidade, o objetivo desta série de três artigos é trazer, aos ortodontistas iniciantes na técnica, considerações práticas para o início do emprego na fabricação própria de alinhadores. Adicionalmente, objetiva-se compartilhar, com os profissionais que já são usuários desse tipo de sistema, experiências relacionadas à fabricação e à gestão da técnica. (AU)

Abstract Clear aligner treatment has gained interest among orthodontists since its introduction in the market two decades ago. The high patients' demand for more aesthetic approaches, with greater comfort, is the primary aspect driving this direction change in the treatment of the malocclusions. However, this drift impacted the management of clinical practices because orthodontists lost absolute control over the flow of assembly and manufacture of conventional appliances. Third-party companies hired for the industrial manufacture of aligners was the concept initially proposed by Align Technology, manufacturer of Invisalign, a pioneer in the commercial system and market leader. Nevertheless, due to the inherent costs of this service and the time limitations imposed by outsourcing, the orthodontists created a digital flow for in-house manufacturing of aligners. This series of three articles brings practical considerations for using in-office aligners. Additionally, the goal is to share experiences related to the manufacture and management of the technique (AU)

Guia prático de fabricação de alinhadores in house ­ Parte 3: impressão de modelos, pós-processamento, termoplastificação, acabamento e gestão clínica / Practical guide for manufacturing aligners in house ­ Part 3: printing models, post-processing, thermoplasticization, improvement and clinical management

Resumo Após o planejamento virtual dos movimentos ortodônticos em plataformas apropriadas e a exportação dos diversos modelos digitais de subsetups, inicia-se a fase laboratorial de fabricação dos alinhadores in house, com a impressão 3D de modelos em resina fotossensível, seguida dos processos de lavagem e pós-cura. Assim, os modelos estarão prontos para serem estampados com variadas opções de laminados poliméricos termoplastificados, que serão recortados, receberão acabamento fino, higienizados e entregues aos pacientes. Na terceira parte do tutorial, serão apresentados esses conceitos práticos da fabricação de alinhadores in house. (AU)

Abstract Following the virtual planning of orthodontic movements using suitable platforms and the resulting exportation of multiple digital models of sub-setups, the laboratory phase begins to produce in house aligners. This phase involves the utilization of 3D printing technology to fabricate models using photosensitive resin, followed by additional steps of washing and post-curing. The models are then prepared for printing using a range of thermoplastic polymer laminate choices. After this, they are meticulously trimmed, refined, sterilized, and subsequently, disseminated to the intended recipients. The current part 3 of the tutorial will focus on the practical concepts involved in the in house production of aligners(AU)

Analysis of the Changes in Occlusal Plane Inclination in a Class II Deep Bite "Teen" Patient Treated with Clear Aligners: A Case Report.

Background: Optimal management of hypodivergent growing patients demands a strict control of vertical dimension and to exploit the growth potential. If a deep bite malocclusion causes a traumatic contact between the upper and lower incisors and affects the facial appearance, an early interceptive treatment is recommended. The aim of this case report is to outline the clinical management of the occlusal plane of a growing Class II division 1 deep bite patient treated with aligners and Class II elastics. Methods: The treatment lasted 11 months and was divided into two phases. Treatment goals included improvement of the soft tissue profile and basal bone relationships through an increase in the mandibular third of the face and a sagittal advancement of the mandible. The correction of the curve of Spee involved intrusion of the mandibular incisors and extrusion of the mandibular premolars. Results: The cephalometric analysis at the end of the treatment displayed significant differences in the skeletal and occlusal pattern along with aesthetic improvements. Conclusion: The final cephalogram showed a consistency between the planned tooth movement and the clinical results. Although definitive recommendations must be withheld until longer follow-up is available, the patient presented here shows that the treatment protocol yielded positive mandibular growth.

Occlusal Plane Modification in Clear Aligners Treatment: Three Dimensional Retrospective Longitudinal Study.

The purpose of the present study was to evaluate: (i) maxillary occlusal plane changes after clear aligners therapy with a 3D measurement technique; and (ii) as a secondary outcome, if such changes were correlated to the patient's 1axilla-mandibular divergence. 3D maxillary models of 32 patients (7 males and 25 females; mean age 22.3 +/− 3.4 year) treated with clear aligners were analyzed. The angle (α) between a reference palatine plane and a maxillary occlusal plane was measured. Five angular cephalometric measurements (NSL/MP; PP-OP; OP-MP; PP-MP; PFH/AFH%) were performed and related to Δα. The subjects were further divided into three groups according to facial divergence. After aligner treatment, Δα increased in hyperdivergent patients and decreased in hypodivergent patients (p < 0.05). Δα showed a significant positive correlation with NSL/MP (rho = 0.44) and negative correlation with PFH/AFH% (rho = −0.53). Aligners treatment produced a counterlockwise rotation of the maxillary occlusal plane, even if this rotation occurs differently depending on divergence.

The combined use of clear aligners and computer-guided piezocision: a case report with a 2-year follow-up.

AIM: An orthodontic treatment is described that combines the use of clear aligners and computer-guided piezocision to overcome the drawbacks of traditional corticotomy in accelerating orthodontic tooth movement. The relapse at the 2-year follow-up was also evaluated. MATERIALS AND METHODS: A 13-year-old male patient was selected and treated due to a molar Class II malocclusion with moderate dental crowding. Treatment time, oral health-related quality of life (OHRQoL), and periodontal indexes were assessed. To reduce the treatment time, computer-guided piezocision was utilized to perform flapless interproximal corticotomy cuts through the depth of the cortical bone. The orthodontic therapy using clear aligners began on the same day as the surgery. RESULTS: The overall duration of the therapy was 6 months. There was an improvement in the periodontal indexes at the end of the therapy. An aggravation of OHRQoL only occurred for 3 days after surgery. The 2-year follow-up evaluation showed a relapse of 0.2 mm on the maxillary left lateral incisor and 0.25 mm on the mandibular right lateral incisor. CONCLUSION: The present case report describes the advantages of a combination of computer-guided piezocision and clear aligners to treat a Class II malocclusion with moderate crowding.