A vital microscopy morphology of study of normal the and inflamed gingiva

Using a specially constructed microscope and transilluminating the intact free gingiva of ferrets, opossums, cats, dogs and rhesus monkeys, blood flow and vascular morphology were observed. Recordings were made on motion picture film at speeds up to 300 frames per second. The state of health of the gingiva was assessed clinically, histologically and by vital microscopy and the three assessments compared. The results indicate that free gingiva which have never been involved in inflammation exhibit a vascular morphology which can be described as a network. With the onset of histopathologic inflammatory changes, the network transforms to a characteristic loop appearance. Five stages of morphologic change are described, based upon the vascular topography seen at various stages of the cellular inflam‐ matory response. It is concluded that the vascular changes of inflammation in the free gingiva of the species studied, precede clinical and epithelial changes.