title: Development of novel implant abutments using the shape memory alloy nitinol: preliminary results.
abstract: OBJECTIVE
  The development of gap-free abutments is a challenging problem, because the gap between the implant and the abutment, which is a consequence of current manufacturing limitations, can serve as a reservoir for pathogens. This may lead to peri-implantitis, a major cause of implant failure. Therefore, the aim of this study was to design and fabricate a gap-free abutment using a shape memory alloy with improved ability to prevent microleakage at the implant-abutment gap.
  
  
  METHODS
  The abutment was designed using the shape memory alloy nitinol and based on mathematical calculations considering the temperature-related, reversible changes to its crystalline alloy structure. The abutment prototypes were tested for their susceptibility to microbes in vitro, under static and dynamic conditions, by contaminating the abutments before assembly using a bacterial solution. Microbacterial tests were performed after cultivation of the implants for 1 week. The results were tested for statistically significant differences using the chi-square test.
  
  
  RESULTS
  The mathematical calculations met the clinical requirements using a contact pressure of 2 3 108 Nm2 with a preload of 1.9 kN on cooled abutments. After recooling, the contact pressure was 1.3 Nm2, allowing for easy disassembly. Microbacterial analysis revealed no penetration of Escherichia coli under static conditions either in the control group or in the prototypes. Under dynamic conditions, however, the prototypes showed significantly reduced bacterial leakage compared to the controls.
  
  
  CONCLUSIONS
  The data presented here demonstrate that dental implants fabricated with gap-free abutments using a shape memory alloy showed significantly reduced bacterial leakage versus conventional implants. This improvement could minimize clinical problems such as peri-implantitis and consequently enhance the long-term success of dental implants.
authors: Department of Oral and Maxillofacial Surgery, Technische Universitat Munchen, Munich, Germany.
authors: Christoph
authors: C
authors: Pautke
authors: Andreas
authors: A
authors: Kolk
authors: Martin
authors: M
authors: Brokate
authors: Jan Christoph
authors: JC
authors: Wehrstedt
authors: Felix
authors: F
authors: Kneissl
authors: Thomas
authors: T
authors: Miethke
authors: Erwin
authors: E
authors: Steinhauser
authors: Hans-Henning
authors: HH
authors: Horch
authors: Herbert
authors: H
authors: Deppe
mesh_terms: D000497:Alloys; D019245:Compressive Strength; D000044:Dental Abutments / Q000382:microbiology; D003722:Dental Alloys; D015921:Dental Implants / Q000382:microbiology; D003763:Dental Leakage / Q000517:prevention & control*; D017267:Dental Prosthesis Design; D003799:Dental Stress Analysis; D004548:Elasticity; D009532:Nickel; D013696:Temperature; D014025:Titanium
chemical_list: D000497:Alloys; D003722:Dental Alloys; D015921:Dental Implants; C093824:Martensite; C093826:Austenite; C013616:nitinol; D009532:Nickel; D014025:Titanium