title: Influence of different maintenance times of torque application on the removal torque values to loosen the prosthetic abutment screws of external hexagon implants.
abstract: OBJECTIVE
  To analyze the torque application on prosthetic abutment screws using different maintenance times, to determine an influence on the removal torque values.
  
  
  METHODS
  A total of 40 external hexagon implants, 40 titanium screws, and 40 customized abutments were used. In group 1, the screws received a torque of 30 N·cm by instant torque application; in groups 2, 3, and 4, torque of 30 N·cm was applied and maintained for 10, 20, and 30 seconds, respectively. Removal torque was performed 10 minutes after torque application. Data were statistically analyzed using 1-way ANOVA and Tukey HSD test (α = 0.05).
  
  
  RESULTS
  The mean and standard deviation (±SD) of removal torque values found were 11.61 ± 1.43 N·cm for group 1; 18.64 ± 1.71 N·cm for group 2; 21.62 ± 0.97 N·cm for group 3; and 21.48 ± 1.55 N·cm for group 4. Groups 3 and 4 exhibited statistically higher values than group 2, which demonstrated significantly higher values than group 1 (P < 0.05).
  
  
  CONCLUSIONS
  A torque of 30 N·cm applied for 20 seconds seemed to be the best option when considering the removal torque values of external hexagon implants.
authors.affiliation: *Lecturer, Federal University of Santa Catarina, Florianópolis, Santa Catarina, Brazil. †Associate Professor, Partial Denture of the Federal University of Santa Catarina; Professor, Master in Dentistry, Area of Prosthodontics/UFSC; Professor of the Specialization Course in Prosthodontics, Florianópolis, Santa Catarina, Brazil. ‡Associate Professor, Partial Denture of the Federal University of Santa Catarina; Professor of the Specialization Course in Implantology at the Center for Teaching and Research on Dental Implants/UFSC; Professor of the Specialization Course in Prosthodontics, Florianópolis, Santa Catarina, Brazil. §Associate Professor, Department of Prosthodontics, Faculty of Dentistry, Dumlupinar University, Kutahya, Turkey. ‖Professor, Dental Materials Unit, Center for Dental and Oral Medicine, Clinic for Fixed and Removable Prosthodontics and Dental Materials Science, University of Zürich, Zürich, Switzerland.
authors.forename: Gustavo Castellazzi
authors.initials: GC
authors.lastname: Sella
authors.forename: Armando Rodrigues
authors.initials: AR
authors.lastname: Lopes Pereira Neto
authors.forename: Cláudia Angela
authors.initials: CA
authors.lastname: Maziero Volpato
authors.forename: Diego Klee
authors.initials: DK
authors.lastname: de Vasconcellos
authors.forename: Gurel
authors.initials: G
authors.lastname: Pekkan
authors.forename: Mutlu
authors.initials: M
authors.lastname: Ozcan
mesh_terms: D000044:Dental Abutments; D015921:Dental Implants; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D006801:Humans; D019415:Torque
chemical_list: D015921:Dental Implants