Predictability and Effectiveness of Nuvola® Aligners in Dentoalveolar Transverse Changes: A Retrospective Study.

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.

Failure rates and factors associated with infrazygomatic crestal orthodontic implants - A prospective study.

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.

Rate of upper incisor retraction in Class II division 1 patients managed with palatal versus buccal miniscrew supported segmental orthodontics: Randomized parallel clinical trial.

OBJECTIVE: This study was conducted to compare maxillary incisor retraction rates using buccal orthodontics with segmented arch approach supported by a buccal or palatal mini-screw in non-growing Class II Division 1 patients during a 3-month period. PATIENTS AND METHODS: All patients between September 2018 and December 2021 with following criteria were included: non-growing class II division 1 protrusion, indication for premolar extraction, no or little crowding, normal overbite, no previous orthodontic treatment, no systematic disease, good oral hygiene, no periodontal problems or oral habits. Mini-implant was inserted buccally or palatally between upper second premolar and first molar bilaterally. Incisor retraction was manipulated by a 200-gram force through a nickel-titanium closed-coil spring extended from the mini-implant to the segmental design. Study casts were made before retraction and after every 4 weeks (T0: baseline, T1: 4 weeks, T2, 8 weeks, T3: 12 weeks). A repeated measures ANOVA was performed for total comparison of data (mm of retraction) on 3D casts. A pairwise t test with Bonferroni correction was used for comparison between two experimental periods for the same group. An independent samples t-test was also used for comparison between two groups for the same experimental period. RESULTS: Of 30 patients meeting the eligibility criteria, only 28 were included with mean age 16±2.5 years. Repeated measures ANOVA revealed significant differences in incisor retraction between the time intervals for both buccal and palatal groups (P=0.001). In addition, the paired-sample t test indicated a significant difference between each time interval for both the buccal and palatal groups (P=0.001), except between T3 and T2 for the palatal group (P=0.09). The independent sample t-test revealed significant differences between the buccal and palatal groups at T1 (Mean: 0.55 [0.355-0.748],=0.001) and T2 (Mean: 1.4 [0.91-1.88], P=0.001); whereas no significant difference was found at T3 (Mean: 1.15 [0.67-1.63], P=0.945). CONCLUSIONS: Anterior retraction using a segmental palatal model with mini-screws was effective regardless of the buccal or palatal situation of the minivis. Retraction of incisors with palatal miniscrews was significantly faster in the first two months.

Tubos cerâmicos impressos em 3D: controle rotacional do primeiro molar superior / 3D printed ceramic tubes: rotational control of maxillary first molar

No final da década de 70, ocorreu a introdução da tecnologia de desenho assistido por computador e fabricação assistida por computador (CAD/CAM) na Odontologia. As principais proposições dessa tecnologia seriam automatização do processo manual minimizando as variações ou falhas humanas. Dentre os benefícios do produto citado, destacam-se a possibilidade de individualização dos acessórios de acordo com as necessidades biomecânicas do paciente, personalizando a sua prescrição e o formato da sua base para melhor adaptação ao dente, dando ao ortodontista a possibilidade de alcançar finalizações de tratamentos muito mais precisas. A posição do primeiro molar superior tem grande importância para a clínica ortodôntica. As rotações dos primeiros molares superiores estão presentes na maioria das más oclusões, principalmente na má oclusão de Classe II de Angle Divisão 1, que aumenta o espaço ocupado pelos dentes na arcada dentária. O presente estudo avaliou in vitro o desempenho dos tubos no controle rotacional dos molares superiores. Nesta pesquisa, os tubos foram colados em primeiros molares superiores esquerdos artificiais de resina, aleatoriamente, divididos em quatro grupos, de acordo com o tipo de tubo utilizado e posicionamento de colagem. Os seguintes grupos foram testados: Grupo 1: Tubo cerâmico prototipado, colado na posição central; Grupo 2: Tubo cerâmico prototipado, colado na posição distal; Grupo 3: Tubo simples metálico colado na posição central e Grupo 4:Tubo simples metálico colado na posição distal. Para a execução dos testes, hemiarcadas superiores esquerdas contendo desde o dentes incisivo central superior ao segundo molar superior esquerdo foram obtidas por arquivo STL (Standard Triangle Language) através do software americano Autodesk Meshmixer. Os tubos ortodônticos foram fixados por colagem indireta com cianoacrilato na face vestibular dos dentes. Para a avaliação da eficiência dos tubos ortodônticos na correção da rotação do primeiro molar superior foi necessária a utilização de um simulador eletrônico, com o objetivo de padronizar os testes para todas as amostras pesquisadas. Testes T de student e Mann-Whitney foram aplicados para avaliar diferença estatística entre os resultados obtidos nos grupos. Na posição Central, a média dos pulsos de correção dos tubos cerâmicos prototipados (39.41 pulsos) foi superior à média dos tubos metálicos (27.37 pulsos) (teste T de Student p<0.05). Na posição distal, a média dos pulsos de correção dos tubos cerâmicos prototipados (38.38 pulsos) foi superior à média dos tubos metálicos (18.07 pulsos) (teste de Mann-Whitney, p<0.05). Tubos cerâmicos prototipados obtiveram uma maior intensidade da correção da rotação do molar superior que os tubos metálicos, através da metodologia adotada na presente pesquisa, nas duas situações avaliadas. (AU)

At the end of the 1970s, computer-aided design and computer-aided manufacturing (CAD/CAM) technology was introduced into dentistry. The main propositions of this technology would be the automation of the manual process, minimizing human variations or errors. Among the benefits of the product, the possibility of individualizing the accessories according to the patient's biomechanical needs stands out, customizing their prescription and the shape of their base for better adaptation to the tooth, giving the orthodontist the possibility of achieving complete much more accurate treatments. The position of the upper first molar is of great importance for the orthodontic clinic. Rotations of the upper first molars are present in most malocclusions, especially in Angle Class II Division 1 malocclusion, which increases the space occupied by the teeth in the dental arch. The present study evaluated in vitro the performance of the tubes in the rotational control of upper molars. In this research, the tubes were bonding to artificial resin upper left first molars, randomly, divided into four groups, according to the type of tube used and gluing positioning. The following groups were tested: Group 1: Prototyped ceramic tube, bonded in the central position; Group 2: Prototyped ceramic tube, bonded in the distal position; Group 3: Simple metallic tube bonded in the central position and Group 4: Simple metallic tube bonded in the distal position. For the execution of the tests, upper left hemiarchs containing from central incisor teeth superior to the upper left second molar were obtained using an STL (Standard Triangle Language) file using the American software Autodesk Meshmixer. The orthodontic tubes were fixed by indirect bonding with cyanoacrylate on the buccal surface of the teeth. To evaluate the efficiency of orthodontic tubes in correcting the rotation of the upper first molar, it was necessary to use an electronic simulator, with the aim of standardizing the tests for all samples researched. Student's T and Mann-Whitney tests were applied to evaluate statistical differences between the results obtained in the groups. In the Central position, the average correction pulses for the prototyped ceramic tubes (39.41 pulses) were higher than the average for the metallic tubes (27.37 pulses) (Student's T test p<0.05). In the distal position, the average correction pulses for the prototyped ceramic tubes (38.38 pulses) were higher than the average for the metallic tubes (18.07 pulses) (Mann-Whitney test, p<0.05). Prototyped ceramic tubes obtained a greater intensity of correction of upper molar rotation than metallic tubes, through the methodology adopted in the present research, in the two situations evaluated. (AU)

Smart Flexible 3D Sensor for Monitoring Orthodontics Forces: Prototype Design and Proof of Principle Experiment.

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.

Efficiency of maxillary total arch distalization using temporary anchorage devices (TADs) for treatment of Class II-malocclusions: A systematic review and meta-analysis.

OBJECTIVES: To evaluate the treatment effects and post-treatment stability of the maxillary total arch distalization using TADs during the non-extraction treatment of class II malocclusions. MATERIALS AND METHODS: Study involved an electronic search followed by hand searching for randomized and non-randomized clinical studies about maxillary total arch distalization using TADs. After data extraction and risk of bias assessment, meta-analysis was performed for dental, skeletal and soft tissue changes using the Generic-inverse variance approach by use of the mean difference and random-effect model. RESULTS: In total, 1788 articles were identified, 88 full texts were screened and 22 studies were found eligible; 17 of them were included in the quantitative analysis. The means of distalization/distal tipping of the maxillary first molar were 4mm/3.17° in adults, 3.95mm/1.61° in adolescents after treatment with the Modified C-Palatal plate (MCPP), while they were 2.44mm/2.91° with the inter-radicular mini-screws. Both MCPP's treatment in adults and inter-radicular mini-screws resulted in significant intrusion of U6 (1.64 and 0.75mm, respectively), while insignificant extrusion of U6 was resulted in adolescents treated by MCPP. MCPP appliances resulted in palatal inclination/extrusion of maxillary incisors U1 (6.77°/2mm in adults, 7.46°/3.14mm in adolescents). In contrast, inter-radicular mini-screws resulted in less palatal less amount of palatal inclination/insignificant intrusion of U1 (2.42°/0.14mm). MCPP treatment also resulted in significant changes in the skeletal measurements (SNA, ANB, occlusal and mandibular planes). Insignificant differences were found between subgroups in the retraction amount of maxillary incisors, as well as the upper and lower lips. In the follow-up of adolescents treated with MCPP, a significant amount of mesial movement, mesial tipping, and extrusion (2.94mm, 2.84°, and 3.94mm, respectively) was found. However, skeletal and occlusal corrections of the Class II relationship were maintained. CONCLUSIONS: Maxillary total arch distalization using TADs can be an effective and stable treatment procedure. However, RCTs or prospective cohort studies are highly recommended to establish a clinical evidence regarding their efficiency.

Orthodontic extrusion in the digital age: a technical note.

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.

Preferência pelo design dos aparelhos ortodônticos entre jovens universitários de diferentes cursos / Orthodontic appliances desing preference among university students from different courses

O objetivo da pesquisa foi avaliar a preferência de jovens universitários de cursos das áreas da Saúde, Exatas e Humanas por diferentes modelos de aparelho ortodôntico. Foram selecionados dois (modelos) indivíduos jovens, um masculino e um feminino. Em seguida, foram confeccionadas 6 imagens simulando aparelhos ortodônticos para cada modelo. Após confeccionar um álbum de fotografias com todas as imagens, os álbuns foram entregues aos estudantes universitários (n=169) com idades entre 18 a 25 anos, juntamente com um questionário. Foram então formados 3 grupos de avaliadores das áreas do conhecimento, Saúde (n=62), Exatas (n=51) e Humanas (n=56). No questionário, os avaliadores identificaram o aparelho de sua preferência, caso fossem ser tratados, apontando nas 6 imagens a ordem de sua preferência. Eles ainda responderam o motivo da escolha daquele modelo de aparelho. Os alinhadores obtiveram maiores avaliações sobre os aparelhos estéticos (5,0). Em contrapartida, os aparelhos metálicos foram os piores avaliados (2,0). Não houve influência da área de estudo e do gênero do avaliador sobre a hierarquia de atratividade na avaliação, no entanto as avaliadoras do sexo feminino da área de Saúde foram mais críticas quanto ao aparelho metálico com ligadura azul. Apesar da área de estudo não ter influenciado na preferência pelo tipo de aparelho, sendo os mais estéticos preferidos sobre os metálicos, as avaliações mais críticas partiram dos estudantes da área de Saúde. (AU)

The aim of the present research was to evaluate the preference of young university students from courses of the health, science, and human areas regarding different orthodontic appliance design. Two (models) young individuals were selected, one male and one female. Then 6 images were made simulating orthodontic appliances for each model. After producing a photo album with all the images, the albums have been given to university students (n=169) aged between 18 and 25 years old, along with a questionnaire. Three groups of evaluators from different areas of knowledge: Health (n=62), Science (n=51) an Human area (n=56) were formed. In the questionnaire, the evaluators identified which device they would prefer if they were treated, indicating the order of their preference on the 6 images. They also answered the reason for choosing that device model. Aligners had higher ratings than aesthetic devices (5.0). On the other hand, metallic appliances were the worst evaluated (2.0). There was no influence of the study area and the evaluator's gender on the hierarchy of attractiveness in the evaluation, however female evaluators from the Health area were more critical regarding metallic braces with blue ligature. Although the study area did not influence the preference for the type of appliance, with the most aesthetic being preferred over metallic ones, the most critical evaluations came from students in the Health area (AU)

Is there any difference between conventional, passive and active self-ligating brackets? A systematic review and network meta-analysis.

AIM: To test the null hypothesis that there was no difference in treatment efficiency between therapies undertaken with conventional (CBs), passive self-ligating (PSLBs) or active self-ligating (ASLBs) brackets. MATERIALS AND METHODS: An electronic search was performed in 3 data bases (Pubmed, Web of Science, Cochrane Library) from their origin up to January 2019. Additional references were hand searched. Search was strictly restricted to randomized controlled trials (RCTs) and split-mouth design studies (SMDs). RCTs and SMDs were initially processed separately and subsequently combined in a network meta-analysis. The following variables were evaluated: treatment duration, number of visits, occlusal outcomes, alignment rate, transverse arch dimensional changes, incisor position modification, rate of space closure, anchorage loss, bond failure, root resorption, perception of discomfort during the initial phase of alignment, time to ligate in or to untie an archwire, periodontal variables, quality of life. RESULTS: On 229 papers, 30 RCTs and 9 SMDs were finally included in this study. Out of 85 comparisons, 16 only revealed statistically significant differences. It was quicker to untie and ligate an 0.014 NiTi arch from/in 6 ASLBs anterior ceramic brackets compared to 6 ceramic CBs. It was also more painful to insert and remove an 0.019×0.025 SS wire in/from PSLB's brackets compared to CB's attachments. Compared to conventional brackets, there was less maxillary incisor proclination with PSLBs in non-extraction cases. Moreover, there was less bleeding on probing 4-5 weeks after bonding with PSLBs compared to CBs brackets. The only significant difference between ASLBs and PSLBs was that alignment was 10 days faster with active self-ligating braces compared with passive self-ligating braces even if treatment duration between ASLBs and PSLBs was not significantly different. The network meta-analysis revealed that IMPA was greater in extractions cases with CBs compared with both ASLBs (+2,5°) and PSLBs (+1,6°). CONCLUSIONS: The vast majority of the studied variables did not show any significant differences between the three types of brackets. The most significant findings were that it was quicker to insert and remove archwires from ASLBs compared to CBs, and it was more painful to insert and remove an 0.019×0.025" stainless steel wire in/from PSLBs compared to CBs. The major difference between ASLBs and PSLBs was that alignment was 10 days faster with active self-ligating braces compared with passive self-ligating braces even if treatment duration between ASLBs and PSLBs was not significantly different. Most of the claims put forward by the suppliers were not substantiated by our network meta-analysis.

Disentangling the effects of CAD/CAM customized appliances and piezocision in orthodontic treatment.

OBJECTIVES: To discern the effects of computer-aided design (CAD)/computer-aided manufactured (CAM) customized appliances and piezocision on orthodontic treatment (OT). MATERIALS AND METHODS: The study combined findings from two previously published randomized controlled trials: (1) standard OT vs piezocision-assisted standard OT, and (2) CAD/CAM OT vs piezocision-assisted CAD/CAM OT. Piezocision is a minimally invasive corticotomy surgical procedure used to accelerate orthodontic treatment and CAD/CAM refers to CAD/CAM customized brackets and archwires. The outcomes were the overall treatment time, and the durations of the alignment phase and fine-tuning phase. Clinical and radiological features also were evaluated. RESULTS: The combined study included 48 patients with similar baseline characteristics. Compared to the standard treatment, CAD/CAM technology alone significantly decreased the overall median OT time from 543 to 394 days (P < .001) and from 543 to 254 days (P < .0001) when combined with piezocision. Although piezocision significantly reduced the duration of the alignment phase in the mandible and maxilla, CAD/CAM technology considerably shortened the fine-tuning phase. All periodontal and radiographic parameters remained stable from the start to the end of treatment in all groups. CONCLUSIONS: CAD/CAM technology combined with piezocision accelerates the entire OT process, during the alignment phase for piezocision and during the fine-tuning phase for CAD/CAM, with a global reduction of the overall treatment time of more than 50%.

Comparative study of effect of different lever arm positions and lengths on transverse and vertical bowing in lingual orthodontics - An FEM study.

OBJECTIVE: To assess the influence of changing the size and position of lever arm on transverse and vertical bowing effects during retraction in lingual biomechanics. METHODS: A three dimensional 3D finite element method was used to simulate en masse anterior teeth retraction using lingual appliance with sliding mechanics. Two groups were made, 1st group had lever arm mesial to canine while 2nd group had distal to canine. Each group had 4 subgroups with lever arm height varying from 0mm to 12mm. Displacements of the maxillary anterior teeth were noted in each group. RESULTS: As the Lever Arm Height (LAH) increased in group I, the vertical bowing effect reduced while the transverse bowing increased with respect to canines. In group II, both vertical and transverse bowing effects increased but transverse bowing was less as compared to group I. CONCLUSION: Strategic location of the lever arm is required in different clinical situations during en-mass retraction, keeping in mind the location of Centre of Resistance (CRes) as well as the vertical and the transverse bowing effects.

Investment casting with FFF (fused filament fabrication)-printed appliances: the intermediate step.

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.

[Vertical control in clear aligner treatment].

Clear aligners are the fastest-growing appliances in this century, which are not only favored by patients, but also concerned by doctors. This article explains the significance of vertical control in orthodontic treatment, the advantages and disadvantages of vertical control with clear aligner. It also analyzes the causes of the shortcomings and how to use existing technologies and methods to make up for these shortcomings.

Avaliação da retenção e reprodutibilidade dimensional de attachments em alinhadores ortodônticos de diferentes espessuras / Evaluation of retention and dimensional reproducibility of attachments in orthodontics aligners of different thicknesses

Este estudo teve como objetivo avaliar a capacidade de retenção que os attachments proporcionam aos alinhadores ortodônticos, bem como analisar a reprodutibilidade dos attachments a partir do planejamento digital até a sua reprodução clínica. A amostra foi composta por dezesseis modelos, divididos em 2 grupos, sendo oito no grupo controle impresso (GCI), onde os attachments eram impressos no modelo e outros oito modelos no grupo experimental de resina (GER), cujos attachments foram colados manualmente a partir de uma guia de transferência. Cada grupo foi dividido em outros 4 subgrupos, de acordo com o posicionamento dos attachments em determinados dentes e orientação do tal acessório no formato retangular: canino a 2º pré-molar horizontal (HPM), canino a 1º molar horizontal (HM), canino a 2º pré-molar vertical (VPM) e canino a 1º molar vertical (VM). Placas de PETG foram termoformados para um total de 80 alinhadores, sendo 40 para o grupo GCI e outros 40 para o grupo GER nas espessuras de 0.6 mm e 0.8 mm. Os modelos dos grupos GCI e GER foram escaneados e analisados por comparação digital para avaliação da morfologia dos attachments. Em seguida, os alinhadores foram submetidos a ensaio mecânico de tração. A análise qualitativa mostrou que as bases dos attachments colados possuem excesso de resina, dificultando a criação de ângulos vivos. Ao analisar qualitativamente a morfologia do grupo GER foi possível verificar que os attachments colados tiveram suas bases em dimensões maiores que o planejado. O grupo GER apresentou melhores retenções que os grupo GCI. Não há diferença estatística na orientação do acessório e no número de dentes que possuem os dispositivos. Entretanto, há diferença estatística quanto à espessura de PETG onde as placas de 0.8 mm forneceram maior retenção. Neste caso, os attachments horizontais com colagem até os molares apresentam a maior média de retenção estatisticamente significante (p < 0.01) quando comparados aos outros attachments no grupo experimental. Conclui-se que as placas de 0.8 mm conferem retenção superior do que as de espessura 0.6 mm, e também que a combinação de attachments na horizontal com colagem de canino a molar proporcionam maior retenção quando comparados à outra orientação e ao número de dentes envolvidos. (AU)

This study aimed to evaluate the retention capacity that attachments provide to orthodontic aligners, as well as to analyze the reproducibility of attachments made from guides made for this purpose. The sample consisted on sixteen models which were divided into 2 groups, eight in the printed control group (PCG), whose attachments were printed onto the model and eight in the experimental resin group (ERG), whose attachments were bonded manually from transfer guide. Each group was subdivided into 4, according to the positioning and orientation of the attachments: horizontal premolar (HPM), horizontal molar (HM), vertical premolar (VPM) and vertical molar (VM). PETG acetate aligners were thermoformed for a total of 80 aligners, 40 for the PCG group and another 40 for the ERG group in thicknesses of 0.6 mm and 0.8 mm. The models of the PCG and ERG groups were scanned and analyzed by digital comparison to assess the morphology of the attachments. Then, the aligners were subjected to mechanical tensile testing. The qualitative analysis showed that the bases of the bonded attachments have excess resin, making it difficult to create sharp angles. When analyzing the morphology of the ERG group, it was possible to verify they had the bases in larger dimensions than planned. The ERG group had better retentions than the PCG group. There is no statistical difference in the orientation of the accessory and in the number of teeth that the devices have when the attachments are grouped. However, a statistical difference occurs regarding the observed thickness of acetate whose 0.8 mm aligners provided greater retention. In this case, the horizontal attachments with bonding up to the molars have the highest statistically significant retention average (p <0.01) when compared to the other attachments in the experimental group. It is concluded that the 0.8 mm aligners provide superior retention than those of 0.6 mm thickness, and also that the combination of horizontal attachments with molar canine bonding provides greater retention when compared to the other orientation and the number of teeth involved. (AU)

Eficácia polissonográfica de um aparelho intraoral semiflexível em pacientes apneicos resistentes ao CPAP ­ estudo preliminar / Polysomnographic efficacy of a semi-flexible intraoral appliance in CPAPresistant apneic patients ­ preliminary study

INTRODUÇÃO: Os aparelhos intraorais (AIO) possuem indicação para tratamento da Síndrome da Apneia Obstrutiva do Sono (SAOS) inclusive em pacientes com baixa adesão ao CPAP. A polissonografia com o AIO pode confirmar benefício terapêutico. MÉTODOS: Compararam-se os resultados polissonográficos de um AIO semiflexível em pacientes sob uso inadequado do CPAP por meio de estudo-piloto retrospectivo, incluindo 17 pacientes (11 homens e 6 mulheres) com 53,7 +- 7,8 anos, IMC de 27,5 +- 4,1kg/m2 e índice de apneia- -hipopneia basal (IAH) de 35,0 +- 19,8/h. Confirmados o uso inadequado ou recusa do CPAP, os pacientes receberam um aparelho com propulsão semiflexível (A-QUALITY) e, após titulação completa, novas polissonografias foram comparadas aos registros basais e com CPAP. Utilizou-se ANOVA para medidas repetidas e post-hoc Bonferroni (p < 0,05). RESULTADOS: Houve redução semelhante no IAH com AIO (7,7 +- 1,7/h) e CPAP (6,1 +- 1,6/h), ambos comparados ao basal (p < 0,001). O índice de dessaturação de O2 foi reduzido com AIO (2,4 +- 0,6/h) e CPAP (1,3 +- 0,6/h), ambos comparados ao basal (15,7 +- 3,8), (p <0,001). O índice de despertares também foi minimizado com AIO (7,2 +- 1,9/h) e CPAP (4,2 +- 0,7/h), ambos comparados ao basal (18,9 +- 5,3), (p<0,001). A eficiência do sono foi maior com o AIO comparado ao CPAP (87,2 +- 2,1 x 75,6 +- 3,9) (p<0,05). CONCLUSÃO: O tratamento com o aparelho selecionado resultou em melhora nos registros polissonográficos nessa amostra e pode ser indicado como alternativa ao CPAP em pacientes subtratados (AU)

INTRODUCTION: Intraoral appliances (IOA) are indicated for treatment of Obstructive Sleep Apnea Syndrome (OSAS) even in patients with poor adherence to CPAP. Polysomnography with IOA may confirm therapeutic benefit. METHODS: Polysomnographic results of a semiflexible IOA in patients under inadequate use of CPAP were compared by a retrospective pilot study including 17 patients (11 men and 6 women) aged 53.7 +- 7.8 years, BMI of 27.05 +- 4.1kg/m2 and basal apnea-hypopnea index (AHI) of 35.0 +- 19.8/h. Confirmed the inappropriate use or refusal of CPAP, the patients received a semiflexible propulsion device (AQUALITY) and, after complete titration, new polysomnographies were compared to baseline and CPAP registers. ANOVA was used for repeated and post-hoc Bonferroni measurements (p <0.05). RESULTS: There was a similar reduction in AHI with OA (7.7 +- 1.7/h) and CPAP (6.1 +- 1.6/h), both compared to baseline (p <0.001). The O2 desaturation index was reduced with IOA (2.4 +- 0.6 h) and CPAP (1.3 +- 0.6/h), both compared to baseline (15.7 +- 3.8) (p <0.001). Awakening rates were also minimized with IOA (7.2 +- 1.9/h) and CPAP (4.2 +- 0.7/h), both compared to baseline (18.9 +- 5.3) (p <0.001). Sleep efficiency was higher with IOA compared to CPAP (87,2 +- 2,1 x 75,6 +- 3,9) (p <0.05). CONCLUSION: Treatment with the selected device resulted in improved polysomnographic records in this sample and may be indicated as an alternative to CPAP in undertreated patients. (AU)

Investigation of the optimal design of orthodontic mini-implants based on the primary stability: A finite element analysis.

Background. The design of an orthodontic mini-implant is a significant factor in determining its primary stability and its clinical success. The aim of this study was to measure the relative effect of mini-implant design factors on primary stability of orthodontic mini-implants. Methods. Thirty-two 3-dimensional assemblies of mini-implant models with their surrounding bone were generated using finite element analysis software. The maximum displacement of each mini-implant model was measured as they were loaded with a 2-N horizontal force. Employing Taguchi's design of experiments as a statistical method, the contribution of each design factor to primary stability was calculated. As a result of the great effect of the upper diameter and length, to better detect the impact of the remaining design factors, another set of 25 models with a fixed amount of length and diameter was generated and evaluated. Results. The diameter and length showed a great impact on the primary stability in the first set of experiments (P<0.05). According to the second set of experiments, increased taper angle in the threaded and non-threaded area decreased the primary stability. There was also an optimum amount of 2.5 mm for threaded taper length beyond which the primary stability decreased. Conclusion. It is advisable to increase the diameter and length if primary stability is at risk. In the second place, a minimum amount of taper angle, both in the threaded and non-threaded area with an approximate proportion of 20% of threaded taper length to MI length, would be desirable for MIs with a moderate size.

Effects of Class II division 1 malocclusion treatment with three types of fixed functional appliances

ABSTRACT Objective: This study aimed at comparing the dentoskeletal changes in patients with Class II division 1 malocclusion, treated with three types of fixed functional appliances. Methods: A sample comprising 95 patients with the same malocclusion, retrospectively selected, and divided into four groups, was used: G1 consisted of 25 patients (mean age 12.77 ± 1.24 years) treated with Jasper Jumper appliance; G2, with 25 patients (mean age 12.58 ± 1.65 years) treated with the Herbst appliance; G3, with 23 patients (mean age 12.37 ± 1.72 years) treated with the Mandibular Protraction Appliance (MPA); and a Control Group (CG) comprised of 22 untreated subjects (mean age 12.66 ± 1.12 years). Intergroup comparison was performed with ANOVA, followed by Tukey test. Results: The Jasper Jumper and the Herbst group showed significantly greater maxillary anterior displacement restriction. The Jasper Jumper demonstrated significantly greater increase in the mandibular plane angle, as compared to the control group. The MPA group demonstrated significantly greater palatal inclination of the maxillary incisors. Vertical development of the maxillary molars was significantly greater in the Herbst group. Conclusions: Despite some intergroup differences in the amount of dentoskeletal changes, the appliances were effective in correcting the main features of Class II malocclusions.

RESUMO Objetivo: o objetivo do presente estudo foi comparar as alterações dentoesqueléticas em pacientes com má oclusão de Classe II, divisão 1, tratados com três tipos de aparelhos funcionais fixos. Métodos: a amostra compreendeu 95 pacientes, selecionados retrospectivamente e divididos em quatro grupos: G1, composto por 25 pacientes (idade média de 12,77 ± 1,24 anos), tratados com aparelho Jasper Jumper; G2, com 25 pacientes (idade média de 12,58 ± 1,65 anos), tratados com aparelho Herbst; G3, com 23 pacientes (idade média de 12,37 ± 1,72 anos), tratados com o Aparelho de Protração Mandibular (APM); e um Grupo Controle (GC), composto por 22 sujeitos não tratados (idade média de 12,66 ± 1,12 anos) que apresentavam a mesma má oclusão. A comparação intergrupos foi realizada com ANOVA, seguida do teste Tukey. Resultados: os grupos Jasper Jumper e Herbst apresentaram significativamente maior restrição de deslocamento anterior da maxila. O Jasper Jumper demonstrou aumento significativamente maior no ângulo do plano mandibular, em comparação ao grupo controle. O grupo APM demonstrou inclinação palatina significativamente maior dos incisivos superiores. O desenvolvimento vertical dos molares superiores foi significativamente maior no grupo Herbst. Conclusões: apesar de algumas diferenças intergrupos na quantidade de alterações dentoesqueléticas, os aparelhos foram eficazes na correção das principais características das más oclusões de Classe II.

Users' perceptions and preferences towards maxillary removable orthodontic retainers: a crossover randomized clinical trial

Abstract The aim of this study was to assess, correlate, and compare users' perceptions and preference related to maxillary removable retainers. Volunteers were recruited to use four retainer types: conventional wrap-around (CWA), wrap-around with an anterior opening (OWA), "U" wrap-around (UWA), and clear thermoplastic retainer (CT). The main outcomes were the volunteers' perceptions, evaluated with a 100-mm visual analogue scale, and their preferred retainer. The retainers were used for 21 days each (washout intervals of 7 days). Nineteen volunteers (27 ± 4.53 years) were randomly divided into four groups that used the four retainers, but with a different sequence. Perceptions were evaluated immediately after the use of each retainer and the preference at the end of the research. Repeated measures ANOVA and Friedman tests with post-hoc Tukey's test (intergroup comparisons), and Pearson and Spearman analyses (correlations between perceptions) were applied. The WA retainers did not significantly differ among themselves. The CT was rated significantly worse in speech (p ≤ 0.001), discomfort (p < 0.001), and occlusal interference (p < 0.001), and did not significantly differ from the others in esthetics. Users preferred significant more the WA retainers in comparison with the CT retainers. The occlusal interference caused by the CT was positively correlated to other perceptions, such as changes in speech and discomfort. WA retainers presented similar preference and perceptions, but were significantly better than the CT. The CT occlusal coverage appeared to be the primary cause of its rejection.

Evaluation of friction on self-ligating and conventional brackets associated with different types of archwires submitted to sliding mechanics

Aim: The aim of this study was to verify the frictional force during sliding mechanics in orthodontic tooth movement, using conventional metal brackets of the active and passive self-ligating types with stainless steel and copper nickel titanium archwires. Methods: This experimental in vitro study was conducted with conventional metal (Morelli, Sorocaba, SP, Brazil) brackets, active self-ligated (SLI Morelli, Sorocaba, SP, Brazil) and passive self-ligated (SLP Morelli, Sorocaba, SP, Brazil), with slot 0.022 x 0.028 inches and Roth prescription. The brackets were tested with rectangular section 0.019 x 0.025 inch copper nickel titanium and stainless steel archwires. For each type of bracket, 10 sets of plate/bracket/archwire segment (n=10) were fabricated. Non-parametric Kruskal Wallis and Dunn tests were used for comparison between types of brackets and Wilcoxon tests for comparison between types of archwires. Results: The results showed that the frictional force values were higher with copper nickel titanium than with stainless steel archwires (p<0.05). When copper nickel titanium archwires were used, the active self-ligating brackets showed higher frictional force values than the other types, followed by the conventional brackets. Lower frictional force values were observed with passive self-ligating brackets. For stainless steel archwires, no difference was observed between conventional and active self-ligating brackets, the passive self-ligating type presented lower frictional force values than the others. Conclusion: It was concluded that the higher frictional force was observed when active self-ligating brackets were associated with copper nickel titanium archwires. Lower frictional force was verified between passive self-ligating brackets combined with stainless steel archwires

The T-loop in details

ABSTRACT Introduction: The T-loop as designed by Burstone is a space closure spring used in the rational application of orthodontic biomechanics. Despite the diversity of studies, there is still no consensus on the optimal parametric characteristics for its conformation. Objective: This study aimed at reviewing the literature on the force systems released by different conformations of the T-loop, according to the type of anchorage and the main characteristics and factors that influence them. Results: Comparing the studies, the need for standardization was perceived in the methodology to shape the loops, regarding the variables that influence the force system. Most of the experimental studies with this loop do not report the vertical movement, nor the steps and angles that occur in the brackets. Clinical studies have obtained more variable results in relation to vertical acting forces, considering the influence of chewing. Conclusion: There is great potential for future studies with this type of loop, especially using nickel-titanium alloys, in order to achieve a pure translational movement without friction, with optimal and constant levels of force.

RESUMO Introdução: a alça T preconizada por Burstone é um instrumento de fechamento de espaços utilizado na aplicação racional da biomecânica ortodôntica, dentro da técnica do arco segmentado. Apesar da diversidade de estudos, ainda não há consenso quanto às características paramétricas ótimas para a sua conformação. Objetivo: esse estudo teve como objetivo revisar a literatura sobre os sistemas de forças liberados por diferentes conformações da alça T, de acordo com o tipo de ancoragem necessária, salientando suas principais características e os fatores que as influenciam. Resultados: comparando-se os estudos, foi perceptível a necessidade de padronização da metodologia usada para conformar as alças, levando em consideração as variáveis que exercem influência no sistema de forças, de forma a se obter sistemas mais acurados, permitindo a realização de testes mais precisos e uma comparação mais eficaz dos estudos. A maioria dos estudos experimentais com esse tipo de alça não relata a movimentação vertical, nem os degraus e ângulos que ocorrem nos braquetes. Estudos clínicos obtiveram resultados menos rígidos em relação às forças verticais atuantes, levando em consideração a influência da mastigação. Conclusões: há grande potencial para futuros estudos com esse tipo de alça, especialmente utilizando ligas de níquel-titânio, para que se chegue cada vez mais perto de um movimento de translação puro e sem atrito, com níveis de força ótimos e constantes.