Preload evaluation of different screws in external hexagon joint
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Updated: May 26, 2026

Creating Rigidly Stabilized Fractures for Assessing Intramembranous Ossification, Distraction Osteogenesis, or Healing of Critical Sized Defects
Published on: April 11, 2012
Wirley Gonçalves Assunção1, Juliana Aparecida Delben, Lucas Fernando Tabata
1Department of Dental Materials and Prosthodontics, Araçatuba Dental School, Universidade Estadual Paulista (UNESP), Araçatuba, São Paulo, Brazil. wirley@foa.unesp.br
Purpose:
This study compared the maintenance of tightening torque in different retention screw types of implant-supported crowns.
Materials And Methods:
Twelve metallic crowns in UCLA abutments cast with cobalt-chromium alloy were attached to external hexagon osseointegrated implants with different retention screws: group A: titanium alloy retention screw; group B: gold alloy retention screw with gold coating; group C: titanium alloy retention screw with diamond-like carbon film coating; and group D: titanium alloy retention screw with aluminum titanium nitride coating. Three detorque measurements were obtained after torque insertion in each replica. Data were evaluated by analysis of variance (ANOVA), Tukey's test (P < 0.05), and t test (P < 0.05).
Results:
Detorque value reduced in all groups (P < 0.05). Group A retained the highest percentage of torque in comparison with the other groups (P < 0.05). Groups B and D retained the lowest percentage of torque without statistically significant difference between them (P > 0.05).
Conclusions:
All screw types exhibited reduction in the detorque value. The titanium screw maintained the highest percentage of torque whereas the gold-coated screw and the titanium screw with aluminum titanium nitride coating retained the lowest percentage.
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