title: Comparative study of torque resistance and microgaps between a combined Octatorx-cone connection and an internal hexagon implant-abutment connection.
abstract: BACKGROUND
  Although the implant-abutment connection may prevent crestal bone loss around dental implants, its failure often leads to treatment failure. Microgap and micromovement of the implant-abutment connection could be causes of bone resorption around dental implant neck.
  
  
  OBJECTIVE
  The purpose of this study was to compare torque resistance and microgaps between a new cone and index connection (Octatorx) and an internal hexagon implant-abutment connection (Internal hex).
  
  
  METHODS
  Twenty Octatorx and 20 internal hexagon connections were attached with retaining screws at 30 Ncm. In a torsion resistance test, 10 of each type of connection were attached to a universal testing machine. Torque resistance with 90 degrees per minute rotation speed was recorded. For microgap measurement, each of 10 connections was embedded in clear acrylic resin. The blocks were cut longitudinally. Twenty specimens of each connection were evaluated. Twelve measurements of microgaps (6 on each side of specimen) were recorded under scanning electron microscopy.
  
  
  RESULTS
  The average torsion resistance of Octatorx (203.6 ±17.4 Ncm) was significantly greater than that of the internal hexagon (146.4 ±16.1 Ncm, P<.05). For the microgap, there was a significant difference (P=.001) between the median values of Octatorx (1.19 μm) and the internal hexagon (3.80 μm).
  
  
  CONCLUSIONS
  In this study, the new connection, Octatorx, had a smaller microgap and greater torque resistance than the internal hexagon connection.
authors: Associate Professor, Center of Excellence for Dental Implantology, Faculty of Dentistry, Chiang Mai University, Thailand.
authors: Pathawee
authors: P
authors: Khongkhunthian
authors: Researcher, Department of Restorative Dentistry and Periodontology, Faculty of Dentistry, Chiang Mai University, Thailand.
authors: Sakornratana
authors: S
authors: Khongkhunthian
authors: Engineer, Center of Excellence for Dental Implantology, Faculty of Dentistry, Chiang Mai University, Thailand.
authors: Winai
authors: W
authors: Weerawatprachya
authors: Former student, Center of Excellence for Dental Implantology, Faculty of Dentistry, Chiang Mai University, Thailand.
authors: Kanuengnit
authors: K
authors: Pongpat
authors: Doctoral candidate, Center of Excellence for Dental Implantology, Faculty of Dentistry, Chiang Mai University, Thailand. Electronic address: weedentphd@outlook.com.
authors: Weerapan
authors: W
authors: Aunmeungtong
mesh_terms: D000044:Dental Abutments; D059605:Dental Implant-Abutment Design; D015921:Dental Implants; D018772:Dental Marginal Adaptation; D003799:Dental Stress Analysis / Q000295:instrumentation; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D012399:Rotation; D013314:Stress, Mechanical; D013499:Surface Properties; D019415:Torque; D054159:Torsion, Mechanical
chemical_list: D015921:Dental Implants