Influence of tissue expanders on the growing craniofacial skeleton

The effects of chronic pressure on the mandible during skin expansion proce dures have been investigated. In 19 Gottingen miniature pigs with an averag e age of 3 months, tissue expanders were placed s.c. in close proximity to the growing ascending ramus of the mandible on the surface of the masseter muscle. After complete filling of the expanders (100 cc) after 6 weeks, a s ignificant transverse discrepancy could be observed compared with the contr alateral side. Additionally, severe medial dislocation of the molars were n oticed. Ten weeks after the removal of the implant, the occlusal disturbanc e still existed, deviation of the transverse mandibular diameter still reac hed up to -13.6 +/- 2.1%. Because only four animals were measured based on a CT investigation, further statistical analysis was not possible, Histolog ical examination showed osteoclastic activity of the expander with conseque nt bone resorption and remodelling. Strict indications should be agreed for tissue expansion in the vicinity of growing bone, as, for example, when ti ssue expansion is applied in children.