The loadability of the 0.8-mm micro-system in thin midfacial regions--an animal experimental study.

The so-called 2-mm systems are well established in the osteosynthesis of the mid-face. Due to the relatively thin soft tissue covering of most of the mid-face, however, the plates and screws of these systems often appear large, and disturb the patient because they are palpable and/or bulge through the skin. To avoid this disadvantage, more delicate systems have been designed. The question arises here, however, whether the more delicate systems could also be applied in thin mid-face regions that experience high functional loads. This study compares the functional loadability of 0.8-mm Luhr and 2.0-mm AO screws in an animal experimental model. Histological evaluation of the implant beds of the loaded screws showed significant differences in postoperative bone remodelling which could be correlated to the systems. Extrapolation of the results to the clinical situation suggests that care should be exercised when using Micro-Systems in highly loaded regions of the mid-face.