On clinical loading of osseointegrated implants. A methodological and clinical study.

Abstract

Strain gauges were used to record in vivo and in vitro functional deformations in a fixed prosthetic appliance supported and retained by osseointegrated titanium implants. Four linear gauges were attached to each of totally 5 implant abutment cylinders and gauge signals were transferred into a computer via a digital converter. A computer program (ASYST) was used for collection, calibration and analysis of data obtained. Based on the results of a series of explorative in vitro tests, in vivo experiments were performed at maximum biting as well as during chewing on certain normally available food items. The results show fundamental differences between in vitro and in vivo testing conditions. Unexpectedly high bending of the implants was recorded in many of the in vivo loading situations.

Effect of Different Abutments and Connections in Deformation Crestal Bone

“…19,22 Extensometer bonding was performed strategically to record microstrain on the polyurethane in the region adjacent to the implant in the cervical direction according some authors. 19,20,[23][24][25][26][27] But another authors 31,32,36,37 have bonded extensometers onto the surface of prosthetic abutments, but bonding in this region is difficult for the following reasons: the circular shape of the abutments makes bonding difficult and can result in errors during reading; the degree of strain suffered by this region is very low, which may mask the load distribution generated on the implant retention substrate; and the region around the implants is the area of the greatest distribution of masticatory load. 19,[25][26][27] When the load is applied to the cantilever, the extensometer of the implant distal nearest to the cantilever shows greater deformation, and the greater the cantilever length, the greater the surface strain on the bone, corroborating the study by Tashkandi et al 19 We could see at times that when applying the load on the cantilever, the bar bent, which may have influenced the lower results found for some extensometers.…”

“…21,24,30 For some authors, it is the methodology of choice for biomechanical analysis of implant supported prostheses. 21,31 Extensometry is based on the fact that all the metal put under strain by an external force undergoes changes to its electrical resistance. 24,32 The electrical resistance of a metal is directly proportional to its length and inversely proportional to its cross-section.…”

Photoelastic analysis of stress distribution on parallel and angled implants after installation of fixed prostheses

“…The loading threshold tolerated by the bone is not well-known and the failure of osseointegration can be caused by bone resorption as a result of unfavorable stress concentrations 11 . In accordance to Kohn 16 (1992), tension distribution is one of the important factors related to implant success; the tensions should be transferred to the adjacent bone, preferentially in an orientation and magnitude that keep the tissues viability near a physiologic state.…”

Trabecular bone strains around a dental implant and associated micromotions—A micro-CT-based three-dimensional finite element study

“…Naturally, a dental implant is subjected to more complex force systems as measured experimentally (Duyck, 2000;Glantz et al, 1993;Merickske-Stern et al, 1992;Merickske-Stern et al, 1996).…”