pyorrhoea vs Riggs' disease

pyorrhoea and Riggs' disease both are nouns.

Word	Noun	Adjective	Verb	Adverb
pyorrhoea	Yes	No	No	No
Riggs' disease	Yes	No	No	No

As nouns, pyorrhoea and Riggs' disease are synonyms defined as:

pyorrhoea and Riggs' disease: chronic periodontitis; purulent inflammation of the teeth sockets

Other synonyms of pyorrhoea include pyorrhea, pyorrhea alveolaris.

pyorrhoea (noun)	Riggs' disease (noun)
discharge of pus	chronic periodontitis; purulent inflammation of the teeth sockets
chronic periodontitis; purulent inflammation of the teeth sockets