Recently, vari0us surgical techniques have been developed fbr treatment of c0ngenital and acqmred malfbrmatiorB of the craniofacial bones.
Especially, le Fort type I osteotomy and the mandibular sagittal split technique have had wide application apd have produced go0d results.
However, we believe there is great danger when the pterygomaxillary suture is separated during le Fort type I osteotomy.
Some surgeons have rep0rted complications arising fbm 1Le Fort type I oste0tomy such as nasal septum perfbration, vital tooth death, severe bleeding etc.
Despite these facts, the dynamic behavior of craniofacial bones during separation of maxil lary tuberosity fmm the pterygoid plates is unknown.
ln a simuladon experiment of le Fort type I osteotomy using an airdried human skull, we obtained interesting results on the measurement of the principal strain distribution at the time of separation of the pterygomaxillary suture.
Four types of osteotomes were used in this simulation: straight osteotome, Obwegeser, s osteotome swan's neck osteotome and modified swan, s neck osteotome.
Befbre separation of the umlateral pterygomaxillary suture, the minimum principal strain was registered by use of Obewegeser's osteotome.
After separation of the unilateral pterygomaxillary suture, the minimum stmn was measured by use of swan's neck osteotome and straight soteotome (posterior to anterior about 30. to the sagittal plane).
