ABSTRACT
Aim: In dental implant treatment, there is a demand for mechanically stronger implants. Despite the existence of several studies showing the clinical success of narrow diameter implants, most of them are based on pure titanium (cpTi) alloys. There is a few clinical evidences of the success rate of titanium-zirconium (TiZr) narrow diameter implants. The aim of this study was to evaluate the stress distribution in the peri-implant area of narrow diameter cpTi and TiZr implants under axial and oblique loads. Methods: Photoelastic models were produced using epoxy resin (PL2, Vishay Precision Group) from a master model. The implants (cpTi and TiZr; Straumann AG) had 3.3 mm in diameter and 12 mm in height. Loads of 100 N and 200 N were applied to the abutment at angles of 0° (axial), 10°, 20°, and 30° (oblique). A circular polariscope (Eikonal) was used under dark field white-light configuration. The isochromatic fringes were analyzed in the peri-implant region in 5 areas, using ASTM table with isochromatic fringes; cervical-mesial, cervical-distal, mid-mesial, mid-distal and apical. Results: In general, under axial and oblique loads, the stress in the TiZr implant was lower than in the cpTi implant. The load of 200 N produced the highest stress values in cpTi and TiZr implants. In both implants and loads, the fringes were located more in apical area at all angles evaluated. Conclusion: It can be concluded that for small implants, the load inclination and intensity change the pattern of stress distribution and the cpTi implant exhibited the highest peri-implant stress
Subject(s)
Stress, Mechanical , Titanium , Dental Implants , Dental Stress AnalysisABSTRACT
Se forças oclusais excederem a capacidade de absorção do sistema implante/osso, o implante tende a fracassar. O objetivo deste estudo foi avaliar a tensão peri-implantar com e sem utilização de placa oclusal plana sob carregamentos diferentes. Materiais e Métodos: Foram confeccionados cinco modelos fotoelásticos, com um implante em cada. Sobre estes implantes foram instaladas coroas unitárias e construída uma placa oclusal plana. Foram aplicadas cargas axiais de 100N, 200N e 300N, com e sem a presença da placa oclusal plana, por meio da máquina universal de ensaio conjugada ao polariscópio. O teste de Mann-Whitney foi utilizado para comparar os grupos com e sem placa, em todas as condições de carregamento. O teste de Kruskal-Wallis foi utilizado para comparar as tensões decorrentes das cargas de 100, 200 e 300N e também para comparar as tensões nas seis áreas periimplantares analisadas. Resultados: Os resultados dos testes de Mann-Whitney não identificaram diferenças estatísticas (p>0,05) ao comparar as ordens de franjas com e sem a utilização de aparelho oclusal plano, em todas as áreas periimplantares analisadas, sob cargas verticais de 100, 200 e 300N. Os resultados dos testes de Kruskal-Wallis indicaram tensões significativamente maiores nas regiões apicais (p<0,05) e que nas áreas apicais as tensões foram maiores com o carregamento de 300N (p<0,05). Conclusões: A utilização da placa oclusal plana sobre a prótese unitária não reduziu significativamente as tensões nas regiões periimplantares; as tensões tendem a se concentrarem na região periapical e nestas áreas a maior magnitude de força implicou em maior tensão...
Introduction: If occlusal forces exceed the capacity of the implant/bone system, the implant tends to fail. The aim of this study was to evaluate the peri-implant stress with and without use of flat occlusal splint under various loads. Materials and Methods: Five photoelastic models were made with an implant in each. About these implants crowns were installed and built a flat occlusal splint. Axial loads of 100N, 200N and 300N, with and without the presence of the occlusal plane plate, were applied by universal testing machine conjugate to the polariscope. The Mann-Whitney test was used to compare the groups with and without plate, in all conditions of loading. The Kruskal-Wallis test was used to compare the stresses resulting from loads of 100, 200 and 300N and also to compare the peri-implant stresses in the six areas analyzed. Results: The results of Mann-Whitney tests identify no significant differences (p> 0.05) comparing fringe orders with and without the use of flat occlusal appliance, in all peri-implant areas examined under vertical loads 100, 200 and 300N. The results of Kruskal-Wallis tests indicated significantly higher stress in the apical regions (p <0.05) and in the apical areas stresses were higher with the loading of 300N (p <0.05). Conclusions: The use of flat occlusal splint on the unitary prosthesis did not significantly reduce the stress in the peri-implant regions; stress tend to concentrate on the periapical region and in these areas the largest magnitude of force resulted in higher stress...