Three-dimensional morphometric analysis of the effects of subperiosteal palatal soft-tissue expansion in growing cats.

A prospective longitudinal study in 75 growing cats was conducted to evaluate palatal soft-tissue expansion in cleft lip and palate surgery. In 31 cats, palatal scars were induced by simulated Langenbeck surgery at the age of 8 weeks. At the age of 14 weeks, custom-made tissue expanders were inserted in 61 animals. Tissue expansion was performed by weekly inflation in 33 cats (16 without and 17 with scars) for an 8-week period. The remaining 28 cats (14 without and 14 with scars) served as sham groups. A control group was formed by 14 animals (without scars and without tissue expander). The effects of the experimental interventions were evaluated on a series of dental casts during the inflation period and until 8 weeks after removal of the tissue expander. The results indicate that soft-tissue expansion of the palatal mucoperiosteum is feasible. Until 20 weeks of age, no differences were found between both expansion and sham groups. Thereafter, significant soft-tissue surface-area gain was quantified in relation to the base surface and base diameter of the tissue expander. Iatrogenic side-effects of active tissue expansion consisted of significant transversal growth retardation in the anterior part of the bony palate and dentoalveolar structures. After removal of the tissue expanders, some accelerated growth in the tissue-expansion, scarred-tissue group was seen. It is concluded that palatal soft-tissue expansion is possible in growing cats, with and without the presence of palatal scars; however, this technique, like other kinds of palatal surgery, impairs dentomaxillary growth and development.