title: Tightening of healing abutments: influence of torque on bacterial proliferation risk, an in vitro investigation.
abstract: BACKGROUND
  Gap at the implant-healing abutment junction can increase the risk of bacterial proliferation. In this study, we determined the leakage at the microgap, and we evaluated hand screwing among clinicians.
  
  
  METHODS
  The torques tested with nitrogen gas flow were 10, 15, 20, and 30 N cm, and 54 clinicians were asked to torque down a healing abutment as for a surgical procedure.
  
  
  RESULTS
  There were no significant differences between 10 and 15 N cm, with a total lack of tightness. For 20 and 30 N cm, there was a notable decrease in leakage. The torque achieved by hand was <10 N cm for 61.7% of the clinicians, between 10 and 15 N cm for 29.1%, between 15 and 20 N cm for 8.0%, and between 20 and 25 N cm for 1.2%.
  
  
  CONCLUSIONS
  There was a significant difference related to the strength of tightening. Under the conditions of our experiment, the gap of connection was reduced with a torque of ≥20 N cm. Only a small portion of the clinicians could obtain these values by hand. Therefore, a dynamometrical manual wrench should be used to minimize the gap during the osseointegration period.
authors.forename: Philippe
authors.initials: P
authors.lastname: Bousquet
authors.forename: Isabelle Calas
authors.initials: IC
authors.lastname: Bennasar
authors.forename: Paul
authors.initials: P
authors.lastname: Tramini
authors.forename: Maxime
authors.initials: M
authors.lastname: Jacquemot
authors.forename: Frédéric
authors.initials: F
authors.lastname: Cuisinier
mesh_terms: D000328:Adult; D001863:Bone Screws; D002983:Clinical Competence; D000044:Dental Abutments / Q000382:microbiology*; D059605:Dental Implant-Abutment Design; D003757:Dental Implantation / Q000379:methods*; D015921:Dental Implants; D003799:Dental Stress Analysis / Q000379:methods; D005260:Female; D017276:Friction; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D018570:Risk Assessment; D014070:Tooth / Q000382:microbiology* / Q000601:surgery*; D019415:Torque
chemical_list: D015921:Dental Implants