title: Comparative Analysis of Screw Loosening With Prefabricated Abutments and Customized CAD/CAM Abutments.
abstract: OBJECTIVE
  The aim of this study was to determine the stability of computer-aided design and manufacturing (CAD/CAM) and prefabricated abutment by measuring removal torque before and after cyclic loading.
  
  
  METHODS
  Three types of fixture and 2 types of abutments were used. Removable torque was measured after cyclic loading for 5000 cycles between 25 and 250 N for each group. The same procedure was performed twice.
  
  
  RESULTS
  First, removal torque values (Newton centimeter) were measured for stock versus custom abutments as follows: group 1: 27.17 versus 26.67, group 2: 26.27 versus 26.33, and group 3: 37.33 versus 36.67. Second removal torque values (Newton centimeter) were also measured: group 1: 23 versus 23.5, group 2: 22.5 versus 22.33, and group 3: 32.67 versus 32.5. There was no significant difference between the stock and custom abutments in either the first or second removal torque values and also no significant difference among initial tightening torque, first or second removal torque (P > 0.05).
  
  
  CONCLUSIONS
  With precise control of CAD/CAM abutments, good screw joint stability can be achieved.
authors: *Assistant Professor, Department of Prosthodontics, School of Dentistry, KyungHee University, Seoul, South Korea. †Professor, Department of Prosthodontics, School of Dentistry, KyungHee University, Seoul, South Korea. ‡Associate Professor, Department of Prosthodontics, School of Dentistry, KyungHee University, Seoul, South Korea. §Clinical Instructor, Department of Prosthodontics, School of Dentistry, KyungHee University, Seoul, South Korea.
authors: Janghyun
authors: J
authors: Paek
authors: Yi-Hyung
authors: YH
authors: Woo
authors: Hyeong-Seob
authors: HS
authors: Kim
authors: Ahran
authors: A
authors: Pae
authors: Kwantae
authors: K
authors: Noh
authors: Hyeonjong
authors: H
authors: Lee
authors: Kung-Rock
authors: KR
authors: Kwon
mesh_terms: D001863:Bone Screws; D017076:Computer-Aided Design; D000044:Dental Abutments; D059605:Dental Implant-Abutment Design / Q000379:methods*; D017267:Dental Prosthesis Design / Q000379:methods*; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D006801:Humans; D019415:Torque