Osseointegration of a subperiosteal anchoring device in the minipig mandible.
BACKGROUND
Onplants serve as subperiosteal anchorage in the maxilla to facilitate tooth movement. We determined the applicability of onplants and the process of osseointegration in the mandible of minipigs.


METHODS
Thirty-six onplants (OnPlants, Nobel Biocare USA, Yorba Linda, Calif) were positioned in 9 adult animals, 2 on each side. At 3, 6, and 12 weeks after surgery, 3 minipigs were killed. Undecalcified ground sections were evaluated histologically and histomorphometrically.


RESULTS
Nineteen onplants were lost during the observation period. Newly formed bone per tissue volume was 7% +/- 5% (n = 4), 21% +/- 9% (n = 5), and 22% +/- 13% (n = 8) at the 3 observation times. The corresponding percentages of bone-to-implant contact were 15% +/- 22%, 30% +/- 27%, and 44% +/- 35%. The number of bone-to-implant contacts remained stable over time at 1.0 +/- 0.9 contacts per millimeter. The average lengths of bone-to-implant contacts were 0.2 +/- 0.1 mm, 0.3 +/- 0.2 mm, and 0.5 +/- 0.3 mm.


CONCLUSIONS
These results showed a low survival rate of onplants in the mandible and that the early stage of healing is central to the process of osseointegration. Stable placement is a prerequisite for onplant survival in the mandible.
Crismani
Adriano G
AG
Department of Orthodontics, Medical University of Vienna, Vienna, Austria. adriano.crismani@meduniwien.ac.at
Bernhart
Thomas
T
Tangl
Stefan
S
Celar
Ales G
AG
Fugger
Georg
G
Gruber
Reinhard
R
Bantleon
Hans-Peter
HP
Watzek
Georg
G
D000818:Animals; D016299:Dental Implantation, Subperiosteal; D005260:Female; D008297:Male; D008334:Mandible / Q000601:surgery; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation*; D016348:Osseointegration; D013552:Swine; D013556:Swine, Miniature