Abstract
It is the purpose of this report to compare the wound healing process mechanically, biochemically, and histologically after straight type lip plasty with that after Z type lip plasty. Both sides of the upper lips of young rabbits, 4 weeks after birth and 450g in weight, were closed with the same number of 5-0 Nylon interrupted sutures. After rabbits were killed 3, 5, 7, 14 days and 1, 3, 6 months after the operation, the entire lip layer was excised. The tensile strength was measured with Instron tension meter, and the collagen content was determined spectrophotometically by Edward's method. Histological findings were obtained after staining with hematoxylin and eosin.
The following conclusions were obtained.
1. The tensile strength in both groups increased more rapidly than that of previously published reports.
2. The tensiles strength after straight type lip plasty reached the tensile strength of the normal skin faster than that after Z type lip plasty.
3. The increase of tensile strength in both groups was almost parallel to the increase of collagen content during one month after the operation.
4. Histological examination showed that more post operative inflammation was found in Z type lip plasty group than in the straight type lip plasty group.
