Extreme bone atrophy in the upper and / or lower jaw prevents the restoration of the chewing function by means of simple screw implants that are placed in the jawbone for the fixation of a dental prosthesis.
There are not many solutions. There are three in the upper jaw.
One option is to first reconstruct the upper jaw with bone that is harvested from the hip comb or the skull. After 3 months, the raised and widened jaw can then house screw implants that can be loaded with a dental prosthesis after 4 months. The patient has two narcoses, nine months waiting time and a reasonable amount of pain on the hip comb (less on the skull) for over. Complications occur during such major procedures and the damage can be significant.
Zygoma implants are long screw implants that are placed in the cheekbone, where often some bone is found. Their placement also takes place in narcosis. It is less necessary to wait to couple a denture. Their length is disadvantageous. Repetitive chewing load sometimes leads to breakage. In case of extreme atrophy, they sometimes have to be placed so horizontally that they end up on the palate and are laterally removed from the jaw bone. The prosthesis sometimes covers the palate. Sinusitis and soft tissue infections are not exceptional.
AMSJI (additively manufactured subperiosteal jaw implant) is an old concept in a new high-tech dress. After the dentist has realized an ideal dental set-up in wax, a CBCT scan is taken with the scan prosthesis in the mouth.
"Reversed engineering" generates the design of 2 frames (endoprostheses), a connecting piece (suprastructure) and a temporary prosthesis. The titanium components are milled in titanium 3D printing and the suprastructure via CADCAM. The temporary exoprosthesis (dentures) is produced in 3D print polymer.
All pieces fit together seamlessly and are calculated with finite element analysis to resist chewing for 20 years. The endoprostheses are screwed into the jaw under local anesthesia. The patient leaves the kliieken after 2 hours can immediately eat soft food with a fixed prosthesis. Some people prefer this procedure to carry out ambulatory innarcosis, but go home the same day.
There are more options for the lower jaw, especially in the front zone. However, in case of extreme atrophy, the jaw can break when screw implants are placed; even if they are short. The AMSJI concept is then adapted for the lower jaw. The workflow is similar.
° Paresthesia or hypesthesia can be present after overzealous dissection in the area of the infraorbital nerve, or by stretching this structure with a retractor. Recovery is expected within 4-6 months.
° Exposure of an arm needs more careful oral hygiene
° Smoking will cause inflammation and tissue retraction.
° Calculus formation requires more frequent visits to the oral hygienist than every 3 months.
° The screw-holes in the wrap-around bridge may not have been closed with definitive polymer and be prone to food impaction.