Both non-erupted teeth and supernumerary teeth are caused by the condition Gardner syndrome, which occurs when there is presence of multiple polyps in the colon and tumors outside the colon.
Gardner syndrome can be identified based on oral findings, including multiple impacted and supernumerary teeth, multiple jaw osteomas that give a "cotton-wool" appearance to the jaws, as well as multiple odontomas, congenital hypertrophy of the retinal pigment epithelium (CHRPE), in addition to multiple adenomatous polyps of the colon. An impacted tooth is one that fails to erupt into the dental arch within the expected developmental window. Gardner syndrome is an autosomal dominant form of polyposis characterized by the presence of multiple polyps in the colon together with tumors outside the colon. 
