ResumoObjetivoO objetivo deste estudo foi avaliar as tensões e deformações de duas marcas comerciais de mini-implantes ortodônticos geradas após a aplicação de dois tipos de forças (de tração de 200 gf e torção de 20 N.cm) inseridos em duas angulações (45° e 90° em relação ao osso cortical).Material e métodoModelos tridimensionais das duas marcas de mini-implantes (SIN - Sao Paulo, Brasil, e RMO – Coréia do Sul) foram construídos e analisados por análise de elementos finitos (FEA). As análises foram realizadas em simulações no osso cortical, osso esponjoso e no parafuso.ResultadoA análise FEA mostrou que os mini-implantes da marca RMO apresentaram maior deformação elástica quando submetidos à tração e as forças de torção quando comparado aos mini-implantes da marca SIN. Em ambas as marcas testadas, e para os diferentes ângulos de inserção, houve uma maior deformação do osso cortical, com maior tensão localizado no mini-implante. A tensão no mini-implante foi localizado na região do perfil transmucoso.ConclusãoAo comparar as análises de elementos finitos das duas marcas comerciais de mini-implantes, concluiu-se que um maior número de roscas e maior inclinação resultam em menor resistência à deformação e induzem uma maior tensão no osso cortical quando submetidos à forças de torção e tração, especialmente quando inserido em um ângulo de 45º com o osso cortical.

AbstractObjectiveThe aim of this study was to assess the stresses and strains generated after the application of two types of forces (traction of 200 gf and torsion of 20 N.cm) in two types of orthodontic mini-implants inserted at different (45° and 90° to the cortical bone) angles.Material and methodthree-dimensional models of two brands of mini-implant (SIN – Sao Paulo, Brazil, and RMO – South Korea) were exported and analyzed by finite element analysis (FEA). Analyses were performed on simulations of cortical bone, cancellous bone and the screw.ResultFEA analysis showed that RMO mini-implants had greater elastic deformation when subjected to tensile and torsional forces when compared with SIN mini-implants. For both trademarks and insertion angles tested, there was greater cortical bone deformation, but with the greatest strain located on the mini-implant. Tension on the mini-implant was located in its transmucosal profile region.ConclusionWhen comparing the two brands of mini-implants by FEA, it is fair to conclude that that the larger number of threads and their greater angle of inclination resulted in less resistance to deformation and induced a higher level of tension in the mini-implant and cortical bone when subjected to forces, especially when inserted at an angle of 45º to the cortical bone.

Orthodontic mini-implants are used in clinical practice to provide efficient and aesthetically-pleasing anchorage. AIM: To evaluate the hardness Vickers hardness and chemical composition of mini-implant titanium alloys from five commercial brands. METHODS: Thirty self-drilling mini-implants, six each from the following commercial brands, were used: Neodent NEO, Morelli MOR, Sin SIN, Conexão CON, and Rocky Mountain RMO. The hardness and chemical composition of the titanium alloys were performed by the Vickers hardness test and energy dispersive X-ray spectroscopy, respectively. RESULTS: Vickers hardness was significantly higher in SIN implants than in NEO, MOR, and CON implants. Similarly, VH was significantly higher in RMO implants than in MOR and NEO ones. In addition, VH was higher in CON implants than in NEO ones. There were no significant differences in the proportions of titanium and aluminum in the mini-implant alloy of the five commercial brands. Conversely, the proportion of vanadium differed significantly between CON and MOR/NEO implants. CONCLUSIONS: Mini-implants of different brands presented distinct properties of hardness and composition of the alloy.