title: Primary stability of a hybrid self-tapping implant compared to a cylindrical non-self-tapping implant with respect to drilling protocols in an ex vivo model.
abstract: BACKGROUND
  Modifications of implant design have been intending to improve primary stability. However, little is known about investigation of a hybrid self-tapping implant on primary stability.
  
  
  OBJECTIVE
  The aims of this study were to evaluate the primary stability of two hybrid self-tapping implants compared to one cylindrical non-self-tapping implant, and to elucidate the relevance of drilling protocols on primary stability in an ex vivo model.
  
  
  METHODS
  Two types of hybrid self-tapping implants (Straumann® Bone Level implant [BL], Straumann® Tapered Effect implant [TE]) and one type of cylindrical non-self-tapping implant (Straumann® Standard Plus implant [SP]) were investigated in the study. In porcine iliac cancellous bones, 10 implants each were inserted either using standard drilling or under-dimensioned drilling protocol. The evaluation of implant-bone interface stability was carried out by records of maximum insertion torque, the Periotest® (Siemens, Bensheim, Germany), the resonance frequency analysis (RFA), and the push-out test.
  
  
  RESULTS
  In each drilling group, the maximum insertion torque values of BL and TE were significantly higher than SP (p=.014 and p=.047, respectively). In each group, the Periotest values of TE were significantly lower than SP (p=.036 and p=.033, respectively). The Periotest values of BL and TE were significantly lower in the group of under-dimensioned drilling than standard drilling (p=.002 and p=.02, respectively). In the RFA, no statistical significances were found in implants between two groups and between implants in each group. In each group, the push-out values of BL and TE were significantly higher than SP (p=.006 and p=.049, respectively).
  
  
  CONCLUSIONS
  Hybrid self-tapping implants could achieve a high primary stability which predicts them for use in low-density bone. However, there is still a debate to clarify the influence of under-dimensioned drilling on primary stability.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Johannes Gutenberg University Mainz, Augustusplatz 2, Mainz, Germany. takesea@dent.kyushu-u.ac.jp
authors.forename: Takeshi
authors.initials: T
authors.lastname: Toyoshima
authors.forename: Wilfried
authors.initials: W
authors.lastname: Wagner
authors.forename: Marcus Oliver
authors.initials: MO
authors.lastname: Klein
authors.forename: Elmar
authors.initials: E
authors.lastname: Stender
authors.forename: Marco
authors.initials: M
authors.lastname: Wieland
authors.forename: Bilal
authors.initials: B
authors.lastname: Al-Nawas
mesh_terms: D000818:Animals; D003758:Dental Implantation, Endosseous / Q000379:methods*; D015921:Dental Implants; D017267:Dental Prosthesis Design; D017268:Dental Prosthesis Retention; D003799:Dental Stress Analysis; D013516:Oral Surgical Procedures, Preprosthetic / Q000295:instrumentation / Q000379:methods*; D013552:Swine; D019415:Torque
chemical_list: D015921:Dental Implants