title: Influence of residual bone thickness on primary stability of hybrid self-tapping and cylindric non-self-tapping implants in vitro.
abstract: OBJECTIVE
  To assess the primary stability of a hybrid self-tapping implant and a cylindric non-self-tapping implant in an in vitro test model using polyurethane foam.
  
  
  METHODS
  Eighty standardized blocks of cellular rigid polyurethane foam, 2 cm long and 1 cm wide, with different thicknesses of 2, 4, 6, and 9 mm (n = 10 per group) were cut. Two implant systems--a hybrid self-tapping (Tapered Effect [TE], Straumann) and a cylindric non-self-tapping (Standard Plus [SP] Wide Neck, Straumann) were placed in the block specimens. Subsequently, resonance frequency analysis (RFA) was performed. The RFA measurements were made in triplicate on four aspects of each implant (mesial, distal, buccal, and oral), and the mean RFA value was calculated. Subsequently, the tensile load of the implants was determined by pull-out tests. The data were analyzed using one-way and two-way analysis of variance followed by a post hoc Scheffe test and a t test (α = .05). Additionally, the simple linear correlation between the RFA and tensile load values was evaluated.
  
  
  RESULTS
  No statistically significant differences were found between TE and SP in terms of RFA at different bone thicknesses. Starting from a bone thickness of 4 mm, TE implants showed significantly higher tensile load compared to SP implants (P = .016 to .040). A correlation was found between the RFA measurements and tensile load.
  
  
  CONCLUSIONS
  Mechanically stable placement is possible with TE and SP implants in a trabecular bone model. RFA and tensile load increased with greater bone thickness.
authors: Clinic for Preventive Dentistry, Periodontology and Cariology, Center for Dental Medicine, University of Zurich, Zurich, Switzerland.
authors: Marija
authors: M
authors: Divac
authors: Bogna
authors: B
authors: Stawarczyk
authors: Philipp
authors: P
authors: Sahrmann
authors: Thomas
authors: T
authors: Attin
authors: Patrick R
authors: PR
authors: Schmidlin
mesh_terms: D003758:Dental Implantation, Endosseous; D015921:Dental Implants; D017267:Dental Prosthesis Design; D017268:Dental Prosthesis Retention; D054459:Elasticity Imaging Techniques / Q000379:methods*; D006801:Humans; D008443:Maxillary Sinus / Q000033:anatomy & histology; D016348:Osseointegration; D011140:Polyurethanes; D013718:Tensile Strength / Q000502:physiology; D014732:Vibration
chemical_list: D015921:Dental Implants; D011140:Polyurethanes; C028279:polyurethane foam