RESUMO
OBJECTIVES: To evaluate the 3D accuracy of attachment positioning and the adaptation of aligners to attachments using in-house templates made with either polyethylene terephthalate glycol (PETG) or ethylene-vinyl acetate (EVA) and either pressure or vacuum thermoforming machines. MATERIALS AND METHODS: Overall, 140 test specimens were resin-printed. Templates for the attachment bonding were made with 1-mm EVA or 0.5-mm PETG laminates. Orthodontic aligners were manufactured with 0.75-mm PETG. The thermoplastification process was carried out using either vacuum or pressure machines. The positional differences between the virtual and bonded attachments were assessed in the X, Y and Z coordinates. The marginal adaptation between the aligners and the attachments was measured. RESULTS: Minor inaccuracies in the positioning of the attachments were observed in all combinations of thermoforming machines and plastic laminates used to fabricate the templates, mainly in the superior-inferior (Z) dimension. PETG performed better than EVA in the anterior region (p < .05). No association was found between thermoplastification machines and the accuracy of the positioning of the attachments (p > .05). While small misadaptations between the aligners and the attachments were observed, the EVA templates performed better than the PETG templates. CONCLUSIONS: The inaccuracy of the attachment positioning and the misadaptation of the aligners to the attachments were slight. The vacuum and pressure thermoplastification machines showed no difference in attachment positioning accuracy. The PETG template was better than the EVA template in the anterior region, but the EVA attachments presented a better adaptation to the aligners than the PETG attachments.
RESUMO
Este relato de caso clínico tem como objetivo descrever a utilização de osso alógeno na reconstrução de maxila atrófica para posterior reabilitação com prótese fixa metalocerâmica sobre implantes, fazer uma análise histológica do tecido ósseo enxertado e descrever o acompanhamento clínico e radiográfico por 8 anos. Uma paciente de 54 anos, com edentulismo parcial e atrofia moderada-a-severa na maxila, apresentou-se para tratamento demonstrando muito interesse em receber prótese sobre implantes. Após exame clínico e radiográfico, foi realizada montagem dos modelos de estudo em ASA para enceramento diagnóstico e obtenção de um guia multifuncional (tomográfico/ cirúrgico). A tomografia indicou a necessidade de reconstrução óssea maxilar. Procedeuse então à aposição de blocos de osso alógeno para aumento horizontal nas regiões anterior e posterior da maxila. Um dos blocos foi triturado e utilizado para levantamento do assoalho do seio maxilar no lado esquerdo. Dez meses depois, uma nova tomografia foi solicitada, utilizando o mesmo guia inicial, e os implantes instalados, utilizando o guia multifuncional como guia cirúrgico. Neste momento, material ósseo foi coletado na interface osso enxertado/osso nativo com uma broca trefina. Os resultados histológicos demonstraram viabilidade das células ósseas no enxerto, além da presença de vasos sanguíneos. Após o tempo necessário para osseointegração, procedeu-se com tratamento protético. Nenhuma complicação foi relatada até oito anos de controle. A sequência de tratamento proposta forneceu bons resultados estéticos e funcionais. Concluiu-se, então, que o emprego de osso alógeno é uma alternativa viável para a reconstrução de rebordos alveolares severamente reabsorvidos(AU)
This clinical case report aims to describe the use of allogeneic bone in the atrophic maxilla reconstruction for subsequent rehabilitation with a fixed metal-ceramic prosthesis on implants; to perform a histological analysis of the grafted bone tissue; and to describe the clinical and radiographic monitoring for 8 years. A 54-year-old patient, with partial edentulism and moderate-to-severe atrophy in the maxilla showed great interest in receiving implant prostheses. After c linical and radiographic examination, the ASA study models were assembled for diagnostic waxing and a multifunctional guide (tomographic / surgical) was obtained. Tomography indicated the need for maxillary bone reconstruction. Allogeneic bone blocks were then placed for horizontal enlargement in the anterior and posterior regions of the maxilla. One of the blocks was crushed and used to lift the floor of the maxillary sinus on the left side. Ten months later, a new tomography was requested, using the same initial guide, and the implants installed, using the multifunctional guide as a surgical guide. At this time, bone material was collected at the grafted bone / native bone interface with a trephine drill. Histological results demonstrated viability of bone cells in the graft, besides the presence of blood vessels. After the necessary time for osseointegration, a prosthetic treatment was performed. No complications were reported up to eight years of control. The propose treatment sequence provided good aesthetic and functional results. It was concluded, then, that the use of allogeneic bone is a viable alternative for the reconstruction of severely reabsorbed alveolar edges(AU)