Implant Failure

 

There are two types of implant failure
Early Failures and Late Failures

EARLY FAILURES

This type of failure occurs shortly after the implants are placed. They can be caused by:

  • Overheating the bone
  • Too much force when they are placed
  • Not enough force when they are placed
  • Contaminated implant
  • Contaminated Osteotomy
  • Epithelial cells in Osteotomy site
  • Poor quality of bone
  • Excessive forces during Osseo integration
  • A myriad of other reasons

 

Late failures

Generally caused by:

  • Excessive forces
  • Lateral loading

Early  failures can be dealt with at the  stage of treatment planning, and diagnostic work up, by  ensuring  an  adequate  surgical  protocol,  and  a  thorough  knowledge  and  understanding  of  the  implant system being placed.

It  goes  without  saying  that  implant  surgery,  like  any  invasive  procedure,  has  to  follow  strict surgical  and  sterilization  protocols,  with  emphasis  being  placed  on  minimal  interval  time  between exposure of the implant from its sterile packaging to its insertion and primary  fixation  in the Osteotomy site.

Implants should never be manipulated by gloved fingers, or the surface contaminated by external sources during the implant placement. Epithelial invagination in the Osteotomy site is a certain precursor to implant failure. Most instances of crestal bone loss usually occurring within a few weeks of placement with an improper protocol of handling.

A large percentage of failures of implants occur in the late phase or the phase of loading. The most significant factor affecting stability of an implant is occlusal loading. Having  mentioned  that  all  implants  are  eventually  prosthetic  driven,  it  is  imperative  that  the occlusal scheme  has  to  be  designed  to  ensure  axial  loading,  and  avoid  excessive occlusal forces  on the implant.  Early signs of excess load fatigue are manifested by loosening of abutment screws, and may eventually lead to implant fractures.

The  ratio  of  implant  to  crown  should  be  ideally  1:1  to  ensure  proper  dissipation of occlusal forces.

Short implants, with an inadequate diameter should be avoided to the greatest possible extent to prevent secondary failures due to inadequate loading.

Cantilever  design,  especially  posterior  cantilevers is  a  precursor to  failure too,  and  may  place excessive load on the implant.