Influence of tissue expanders on the growing craniofacial skeleton

The effects of chronic pressure on the mandible during skin expansion procedures have been investigated. In 19 Göttingen miniature pigs with an average 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 significant transverse discrepancy could be observed compared with the contralateral side. Additionally, severe medial dislocation of the molars were noticed. Ten weeks after the removal of the implant, the occlusal disturbance still existed, deviation of the transverse mandibular diameter still reached up to -13.6 +/- 2.1%. Because only four animals were measured based on a CT investigation, further statistical analysis was not possible. Histological examination showed osteoclastic activity of the expander with consequent bone resorption and remodelling. Strict indications should be agreed for tissue expansion in the vicinity of growing bone, as, for example, when tissue expansion is applied in children.