Initial orthopaedic displacement compared with longitudinal displacement of the maxilla after a forward force application. An experimental study in dogs

The aim of this study was to compare the initial orthopaedic displacement o f the maxilla in vivo and the longitudinal changes after a forward force ap plication. The sample consisted of five 1-year-old dogs. An anterior force of 5 N on the maxilla was applied by a coil spring system pushing between B ranemark implants and a maxillary splint. The initial displacement of the m axilla after force application was measured by means of speckle interferome try. The longitudinal displacement of the maxilla after a force application during 8 weeks was measured by superimposing standardized lateral cephalog rams. The initial, as well as the longitudinal, displacement of the maxilla of th e dogs was in a forward direction with some counterclockwise rotation. Ther e was no statistical difference between the initial and longitudinal displa cement. The biological response after force application during 8 weeks can be predicted by the initial orthopaedic displacement.