W. Bahr et R. Lessing, A COMPARATIVE ANIMAL EXPERIMENTAL-STUDY OF DIFFERENTLY DIMENSIONED OSTEOSYNTHESIS SCREWS USED IN THE MID-FACE, British journal of oral & maxillofacial surgery, 31(6), 1993, pp. 366-369
The soft tissue covering most of the midfacial skeleton is relatively
thin. On account of this plates and screws of the 2 mm systems used in
the osteosynthesis of this region can bulge and/or be palpable throug
h the thin integument. This shortcoming has prompted the need to devel
op smaller systems. The present study was designed to investigate whet
her these more delicate systems are capable of withstanding the midfac
ial forces that come to bear during functional mastication. For the st
udy a Le Fort I osteotomy was carried out in 10 sheep. The mobile maxi
lla was fixed with osteosynthesis plates and screws. This paper report
s on 40 plates and 170 screws of two AO titanium systems. It compares
the strength of 1.5 mm and 2.0 mm AO screws. The anchorage of the scre
ws was assessed by evaluating the nature of contact between the screw
and interfacial bone. The loaded screws showed no discernible differen
ces in postoperative bone remodelling that could be correlated to the
osteosynthesis systems. Although the experimental situation may not be
directly comparable to the trauma or osteotomy case, this study lends
credibility to the assumption that the 1.5 mm screw system could be u
sed instead of the 2.0 mm system, even in mid-face areas associated wi
th high masticatory loads.