Repair of experimental tympanic membrane perforations.

In this investigation the healing pattern of experimental central and marginal pars tensa perforations in cats and rats was studied by using light and scanning electronmicroscopic techniques. The perforations were closed by hyperplastic squamous epithelium exhibiting a marked keratin production. This keratin formed a membranous structure which primarily appeared to close the perforation. No ingrowth of squamous epithelium into the middle ear cavity could be detected. Generally speaking, the perforations had closed within 9-11 days in rats and within 12-14 days in cats.