Experimental Study On Amplifide Labial Gum Soft Tissues With Different Levels Palatal Connective Tissue Flap

Objectives: Compare the healing and aesthetic effect separately after the free mucosa flap from different faults transplantation and offer the theoretical basis for clinic.Materials and methods: Chooses eight 12-16 months'healthy hybrid dogs as the experimental objects. Makes the palatal hard palate zone of the eight dogs under general anesthesia and takes the connective tissue flaps of different faults as reserve. Defect the lip-side gingival of bilateral maxillary anterior tooth, transplant and suture fix the epithelial layer (group A) and connective tissues without epithelial layer (group B) of different faults. Measure the length and width of the mucosa right after the treatment, calculates and records the initial area of transplant mucosa. Execute the animal after 1 week, 2 weeks, 3 weeks, and 4 weeks, and do the clinical inspects, measure the length and width of mucosa, calculate the area, and define the shrinkage of mucosa. Do the histology inspection analysis.Results:1 General observation: Of all the 8 experimental dogs, 1 of the tissue flap exfoliated because of infection, others healed well and had no exfoliate. The edge of transplanted flaps smoothed with the original wound edge of gingival soft tissues, and the transplanted flap of epithelial layer , with rose pink color, had similar thickness with the original gum.2 Morphological observation of HE dyeing:Transplanted flaps of epithelial layer: (1) One week after the operation, the connective tissues of transplanted flaps still had clear boundary with the connective tissues of recipient bed. Many of the inflammatory cells exuded and parts of the epithelial layer degenerated and necrossed; (2)Two weeks after the operation, there was still recognizable boundary between the connective tissues of transplanted flaps and the connective tissues of recipient bed. Fibrous tissues emerged a lot, which made the tissue density of them close to the tissue density of the recipient bed. Epithelial cells of the boundary kept on growing to the surface of the transplanted flap; (3)Three weeks after the operation, quantity of the vessels, inflammatory cells and the fibroblasts in the connective tissues of transplanted flap decreased obviously. The connective tissue density of transplanted flap got close to the tissue density of the recipient bed. Boundary of the two did not obvious any more. The epithelial tissues had already covered the whole flap. The epithelial surface-irregularities get decreased and shoaling; (4) Four weeks after the operation,inflammatory cells in the connective tissues of transplanted flap could rarely be seen. The connective density of transplanted flap increased and was unanimous with surrounding organizations and boundary between the two could not be recognized. Thickness of the epithelial tissues went normal with thick parakeratosis layer on the surface.Flap of connective tissues without epithelial layer: In the microscope, healing process of connective tissues changed consistent with the trans- planted flaps of epithelial layer, while the epithelial cells grew slower than the epithelial layer.3 Morphological observation of picric acid - sirius red dyeing:By picric acid - sirius red dyeing, all tissue slices appears cardinal red under ordinary microscope, especially the big collagen fiber, and there were no diversity between groups. Under the polarized light, there was mainly typeâ… collagen in normal gingival soft tissues. The typeâ… collagen fibers, which appeared red or yellow, disposed tight and orderly, and showed strong double light refraction. In the transplanted flap, the typeâ… collagen fibers reduced significantly. As the healing period lengthened, the quantity of typeâ… collagen fibers increased gradually. At about the fourth week, quantity of typeâ… collagen fibers in the transplanted flap got close with those in the original gingival tissue, thinner than the original ones.Conclusions:1 The different connective tissues flaps heal well, and could repair the defection of soft tissues.2 The aesthetic effect of epithelial layer transplant flap is better.3 The subepithelial connective tissue without epithelial layer flap improves the thickness of soft tissues better, at the same time, it release the wound of the tissue donor area owing to the reserved epithelial layer.