We are using cookies to implement functions like login, shopping cart or language selection for this website. Furthermore we use Google Analytics to create anonymized statistical reports of the usage which creates Cookies too. You will find more information in our privacy policy.
OK, I agree I do not want Google Analytics-Cookies
The International Journal of Oral & Maxillofacial Implants
Login:
username:

password:

Plattform:

Forgotten password?

Registration

Int J Oral Maxillofac Implants 10 (1995), No. 5     1. Sep. 1995
Int J Oral Maxillofac Implants 10 (1995), No. 5  (01.09.1995)

Page 529-536


Elongation and Preload Stress in Dental lmplant Abutment Screws
Haack, James E. / Sakaguchi, Ronald L. / Sun, Ting / Coffey, James P.
A common problem associated with dental implant restorations is loosening of screws that retain the prosthesis to the implant. A method was developed to determine initial preload on UCLA-type abutment screws by measuring elongation after applying known tightening torques with a digital torque gauge. Loosening torque was also measured after tightening to 32 N-cm torque for gold alloy abutment screws and 20 N-cm for titanium ahutment screws. Gold alloy and titanium abutment screws were each used to secure a gold UCLA hexed abutment to a titanium implant. Stresses and forces were calculated from the elongation measurements for three regions of each screw. Elongation of the screws after applying the manufacturer's recommended tightening torques were within the elastic range. Induced stresses were 57.5% and 56% of the yield strengths for gold alloy and titanium, respectively. Tightening of screws beyond recommended levels may be possible without producing plastic deformation. At manufacturer's recommended torques, mean preload was 468.2 (± 57.9) N using gold alloy screws and 381.5 (± 72.9) N with titanium screws.

Keywords: biomechanics, elongation, implant, preload, screws