Biomechanical analysis of total arch maxillary distalization using infrazygomatic crest miniscrews: a finite element analysis study.

AIM: To evaluate the maxillary incisors and canine's immediate movement tendency using three different power arms (PA) height levels during total arch maxillary distalization supported on infrazygomatic crest (IZC) miniscrews according to finite element analysis (FEA). METHODS: Three finite element models of the maxilla were developed based on CBCT imaging of a teenage male patient presenting a Class II Division 1 malocclusion in the early permanent dentition. Maxillary complex, periodontium, orthodontic accessories, IZC miniscrews and an orthodontic wire were digitally created. The PAs were placed between canines and lateral incisors and projected at 4, 7, and 10 mm height distances. After that, distalization forces were simulated between PA and IZC miniscrews. RESULTS: The anterior teeth deformation produced in the FEA models was assessed according to a Von Mises equivalent. The stress was measured, revealing tendencies of initial maxillary teeth movement. No differences were found between the right and left sides. However, there was a significant difference among models in the under-stress areas, especially the apical and cervical root areas of the maxillary anterior teeth. More significant extrusion and lingual tipping of incisors were observed with the 4 mm power arm compared to the 7 mm and 10 mm ones. The 10 mm power arm did not show any tendency for extrusion of maxillary central incisors but a tendency for buccal tipping and intrusion of lateral incisors. CONCLUSION: The maxillary incisors and canines have different immediate movement tendencies according to the height of the anterior point of the en-masse distalization force application. Based on the PA height increase, a change from lingual to buccal tipping and less extrusion tendency was observed for the incisors, while the lingual tipping and extrusion trend for canines increased.

Assessment of relapse of skeletal open bite treatment in adult patients treated with molar intrusion using temporary anchorage devices and orthognathic surgery - a systematic review / Avaliação da recidiva do tratamento da mordida aberta esquelética em pacientes adultos tratados com intrusão molar utilizando dispositivos de ancoragem temporária e cirurgia ortognática - uma revisão sistemática

Objetivo: O objetivo deste estudo é avaliar sistematicamente as evidências disponíveis para recidiva do tratamento da mordida aberta esquelética usando dispositivos de ancoragem temporária e cirurgia ortognática. Material e Métodos: Cinco bases de dados eletrônicas como MEDLINE, COCHRANE, SCIELO, GOOGLE SCHOLAR, EMBASE foram pesquisadas sistematicamente até junho de 2020. Os estudos de qualidade metodológica foram classificados por meio da Ferramenta de Avaliação de Qualidade do Projeto de Práticas de Saúde Pública Eficazes (EPHPP). Resultados: No total, 1.005 estudos foram identificados para triagem e 6 estudos foram elegíveis. O instrumento de avaliação da qualidade apresentou qualidade moderada para todos os estudos. A correção imediata pós-tratamento da mordida aberta foi melhor nos estudos cirúrgicos do que nos estudos tratados com TADs. Conclusão: A estabilidade dos resultados do tratamento da mordida aberta anterior foi comparável nos casos tratados em ambas as modalidades de tratamento. A recidiva da mordida aberta anterior foi associada a casos em que a sobremordida pós-tratamento foi mínima. A sobremordida parece ser mais estável quando apenas a maxila foi operada do que com cirurgias bimaxilares. A rotação anti-horária da mandíbula com subsequente redução da altura facial anterior foi melhor na correção cirúrgica do que através de TADs (AU)

Objective: The purpose of this study is to systematically assess the available evidence for relapse of skeletal open bite treatment using temporary anchorage devices and orthognathic surgery. Materials and Methods: Five electronic databases such as MEDLINE, COCHRANE, SCIELO, GOOGLE SCHOLAR, EMBASE were systematically searched up to June 2020. Methodological quality studies were graded by means of the Effective Public Health Practice Project (EPHPP) Quality Assessment Tool. Results: In total, 1005 studies were identified for screening, and 6 studies were eligible. The quality assessment tool showed moderate quality for all the studies. The immediate post treatment correction of open bite was better in the surgical studies than in the studies treated with TADs. Conclusion: Stability of treatment results of anterior openbite was comparable in cases treated in both the treatment modalities. Relapse of anterior open bite was associated with cases in which the posttreatment overbite was minimal. Overbite seems to be more stable when only the maxilla has been operated on than with bi-maxillary surgeries. Counterclockwise rotation of the mandible with subsequent reduction of anterior facial height was better in surgical correction than through TADs. (AU)

The effect of social media on patient acceptance of temporary anchorage devices.

OBJECTIVES: To investigate the relationship between the use of social networking sites (SNSs) on patient perceptions, acceptance, and expectations of treatment using temporary anchorage devices (TADs) and to compare differences between patients from the United Kingdom and Brazil. MATERIALS AND METHODS: Cross-sectional questionnaires were administered to 39 participants at orthodontic practices in the United Kingdom and Brazil about patients' use of SNSs, exposure to TADs on SNSs, and thoughts on extractions, jaw surgery, or TADs as treatment options. RESULTS: UK patients prefer for clinicians to have SNS profiles (P = .022). Most UK and Brazilian patients want to see their clinician's work online (76.7%) and use SNSs to get information about treatment options (76.6%). There was a statistically significant difference in Brazilian patients' acceptance of TADs as a treatment option compared with UK patients, particularly if it meant avoiding extractions (P = .002), avoiding jaw surgery (P = .004), or reducing treatment time (P = .010). Knowledge of TADs was greater in Brazilian patients (P < .001). CONCLUSIONS: Patients use SNSs to obtain information about treatments and prefer clinicians to have social media accounts. Patients exposed to TADs on SNSs are more likely to accept them as an orthodontic treatment option. UK patients have less knowledge of TADs and are therefore less sure to consider TADs as an option. Brazilian patients are more confident in considering the use of TADs. Clinicians should consider increasing their social media presence to accommodate patients' expectations and acceptance of TADs.

Microimplantes, una nueva opción en el tratamiento de Ortodoncia

Los microimplantes son pequeños pines de titanio o de aleación de titanio de 1,2 mm de diámetro y 6 mm de longitud. Están diseñados con una superficie suave para que no se oseointegren. Son utilizados en Ortodoncia como anclaje temporal. Han sido usados como anclaje esqueletal, también para distalizar y protraer molares, intruir molares e incisivos, para el cierre de espacios edéntulos extensos que con los métodos convencionales en ortodoncia habría sido imposible. Los microimplantes son removidos con relativa facilidad una vez efectuado el procedimiento. Como toda técnica nueva, es importante que los clínicos sepan elegir bien en qué casos van a utilizar los micro implantes y los sitios de su colocación.

The miniimplants are small devices of 1,2 mm of wide and 6 mm of length. Manufactured with a smooth machined surface that is not designed to osseointegrate. In orthodontics they are used as temporary anchorage for molar distalization, protraction and intrusion of molars and incisors. Also for closing wide edentulous spaces once considered impossible with conventional orthodontics.. The miniimplants are easily removed. As with any new technique clinicians should be aware in which cases use this devices and the sites of placing them.

Reasons for mini-implants failure: choosing installation site should be valued!

Mini-implant loss is often associated with physical and mechanical aspects that result from choosing an inappropriate placement site. It is worth highlighting that: a) Interdental alveolar bone crests are flexible and deformable. For this reason, they may not offer the ideal absolute anchorage. The more cervical the structures, the more delicate they are, thus offering less physical support for mini-implant placement; b) Alveolar bone crests with triangular shape are more deformable, whereas those with rectangular shape are more flexible; c) The bases of the alveolar processes of the maxilla and the mandible are not flexible, for this reason, they are more likely to receive mini-implants; d) The more cervical a mini-implant is placed, the higher the risk of loss; the more apical a mini-implant is placed, the better its prognosis will be; e) 3D evaluations play a major role in planning the use of mini-implants. Based on the aforementioned considerations, the hypotheses about mini-implant loss are the following: 1) Deflection of maxillary and mandibular alveolar processes when mini-implants are more cervically placed; 2) Mini-implants placed too near the periodontal ligament, with normal intra-alveolar tooth movement; 3) Low bone density, low thickness and low alveolar bone volume; 4) Decreased alveolar cortical bone thickness; 5) Excessive pressure inducing trabecular bone microfracture; 6) Sites with higher anatomical weakness in the mandible and the maxilla; 7) Thicker gingival tissue not considered when choosing the mini-implant.

Reasons for mini-implants failure: choosing installation site should be valued!

Mini-implant loss is often associated with physical and mechanical aspects that result from choosing an inappropriate placement site. It is worth highlighting that: a) Interdental alveolar bone crests are flexible and deformable. For this reason, they may not offer the ideal absolute anchorage. The more cervical the structures, the more delicate they are, thus offering less physical support for mini-implant placement; b) Alveolar bone crests of triangular shape are more deformable, whereas those of rectangular shape are more flexible; c) The bases of the alveolar processes of the maxilla and the mandible are not flexible, for this reason, they are more likely to receive mini-implants; d) The more cervical a mini-implant is placed, the higher the risk of loss; the more apical a mini-implant is placed, the better its prognosis will be; e) 3D evaluations play a major role in planning the use of mini-implants. Based on the aforementioned considerations, the hypotheses about mini-implant loss are as follows: 1) Deflection of maxillary and mandibular alveolar processes when mini-implants are more cervically placed; 2) Mini-implants placed too near the periodontal ligament, with normal intra-alveolar tooth movement; 3) Low bone density, low thickness and low alveolar bone volume; 4) Low alveolar cortical bone thickness; 5) Excessive pressure inducing trabecular bone microfracture; 6) Sites of higher anatomical weakness in the mandible and the maxilla; 7) Thicker gingival tissue not considered when choosing the mini-implant.

As perdas de mini-implantes estão quase sempre relacionadas aos aspectos físicos e mecânicos decorrentes de uma escolha inadequada do local de inserção. Deve se destacar que: a) As cristas ósseas alveolares interdentárias têm flexão e se deformam, e podem não oferecer ancoragem tão absoluta. Quanto mais cervicais, as estruturas são mais delicadas e oferecem menos suporte físico para os mini-implantes; b) as cristas ósseas alveolares triangulares se deformam mais, e as retangulares são menos flexíveis; c) as bases do processo alveolar nos corpos da maxila e mandíbula não têm capacidade flexiva, e seu volume e estruturas são maiores, logo, são mais receptivas para mini-implantes; d) quanto mais próximo da cervical se coloca um mini-implante, maior é o risco de se perdê-lo; quanto mais apical se coloca o mini-implante, melhor é o seu prognóstico; e) avaliar a região tridimensionalmente representa um passo fundamental no planejamento do uso de mini-implantes. Com base nessas considerações, as hipóteses para a perda de mini-implantes são: 1) Deflexão do processo alveolar da maxila e mandíbula, quando fixados em posições mais cervicais; 2) proximidade com o ligamento periodontal e o movimento dentário intra-alveolar normal; 3) densidade óssea menor, pouca espessura e menor volume ósseo alveolar; 4) espessura menor da cortical óssea alveolar; 5) pressão excessiva, induzindo microfraturas ósseas trabeculares; 6) locais de maior fragilidade anatômica mandibular e maxilar; 7) espessura maior do tecido gengival não considerada na escolha do mini-implante.