Small diameter implants were first developed by NobelBiocare as smooth surfaced implants for use as temporary implants that could be implemented as part of a treatment plan as intermediate support for a temporary prosthesis while the permanent implants achieved osseointegration. While conventional diameter (3mm or more) implants were cleared for use by the FDA in 1976, more recently, small diameter (1.8 to 2.9mm) implants have been developed with the same surface characteristics as conventional diameter implants, and were cleared for use by the FDA in 1997. The reasons for use of SDIs are inadequate bone quantity without grafting and a minimally invasive placement procedure. Because grafting is not an alternative often chosen by patients, mini implants offer a successful alternative. They can be highly successful if used to support a lower overdenture.
Prevent Implants FailureMini implants are subject to failure, however. Therefore, there are some requirements to prevent failure: enough bone (4mm in width and 13mm in length), 30Ncm of resistance during placement to indicate sufficient bone quality, the largest SDI possible in available bone--preferably not 1.8mm diameter and length at least 13mm, parallel placement (divergence less than 15 degrees), implants spread out to allow for size of attachment apparatus, no excess tissue thickness at the crest of the bone, and not used in patients who clench or grind. These clinical requirements have been developed by Dr. Gordon Christensen.
Robert G. Tupac, DDS, FACP, Inc., Diplomate, American Board of Prosthodontics (661) 325-1275 | www.drtupac.com 5060 California Ave., #170, Bakersfield, CA 93309