title: Comparative strain gauge analysis of external and internal hexagon, Morse taper, and influence of straight and offset implant configuration.
abstract: OBJECTIVE
  The present study was designed to analyze strain distributions caused by varying the fixture-abutment design and fixture alignment.
  
  
  METHODS
  Three implants of external, internal hexagon, and Morse taper were embedded in the center of each polyurethane block in straight placement and offset placement. Four strain gauges (SGs) were bonded on the surface of polyurethane block, which was designated SG1 placed mesially adjacent to implant A, SG2 and SG3 were placed mesially and distally adjacent to the implant B and SG4 was placed distally adjacent to the implant C. The 30 superstructures' occlusal screws were tightened onto the Microunit abutments with a torque of 10 N cm using the manufacturers' manual torque-controlling device.
  
  
  RESULTS
  There were statistically significant differences in prosthetic connection (P value = 0.0074 < 0.5). There were no statistically significant differences in placement configuration/alignment (P value = 0.7812 > 0.5).
  
  
  CONCLUSIONS
  The results showed fundamental differences in both conditions. There was no evidence that there was any advantage to offset implant placement in reducing the strain around implants. The results also revealed that the internal hexagon and Morse taper joints did not reduce the microstrain around implants.
authors: Department of Dental Materials and Prosthodontics, School of Dentistry of São José dos Campos, São Paulo State University (UNESP), Av. Francisco José Longo 777, São José dos Campos, Brazil. nishioka@fosjc.unesp.br
authors: Renato Sussumu
authors: RS
authors: Nishioka
authors: Luis Gustavo Oliveira
authors: LG
authors: de Vasconcellos
authors: Gabriela Nogueira
authors: GN
authors: de Melo Nishioka
mesh_terms: D001696:Biomechanical Phenomena; D002858:Chromium Alloys / Q000737:chemistry; D000044:Dental Abutments; D003758:Dental Implantation, Endosseous / Q000379:methods*; D015921:Dental Implants; D017267:Dental Prosthesis Design; D006801:Humans; D008422:Materials Testing; D008953:Models, Anatomic; D011140:Polyurethanes / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D019415:Torque; D014159:Transducers
chemical_list: D002858:Chromium Alloys; D015921:Dental Implants; D011140:Polyurethanes