Changes

* When the necrosis is confined to the middle and outer layers of the epithelium (an erosion), the underlying germinal layer divides and replaces the shed portion.  

* When the necrosis is confined to the middle and outer layers of the epithelium (an erosion), the underlying germinal layer divides and replaces the shed portion.  

** Leaves no [[Healing and Repair - Pathology#Scarring|scar]].

** Leaves no [[Healing and Repair - Pathology#Scarring|scar]].

** E.g. in [[Cavity & Gingiva - Pathology#Foot and Mouth disease|Foot and Mouth Disease]]  

** E.g. in [[Foot and Mouth Disease|Foot and Mouth Disease]]  

* When the necrosis extends below the basement membrane of the epithelium and the integrity of the epithelium is compromised (an ulceration), there is an inflammatory reaction.

* When the necrosis extends below the basement membrane of the epithelium and the integrity of the epithelium is compromised (an ulceration), there is an inflammatory reaction.

** An attempt is made to repair the deficit by fibrous tissue.  

** An attempt is made to repair the deficit by fibrous tissue.