Investigation of the role of endotoxin in periapical inflammation.

Denta l pu lp s in two dogs w e r e r e m o v e d and the canals shaped in six m a t c h e d pairs of roots. Canals on the e x p e r i m e n t a l side we re injected w i t h Salmonella minnesota R-595 e n d o t o x i n a n d canals on the cont ra la tera l con t ro l side w e r e in jec ted w i th saline so lu t ion at w e e k l y intervals . Rad iograph ic e x a m i n a t i o n s we re p e r f o r m e d week ly , and his tologic eva lua t ions we re m a d e at four to five weeks . Per iapical r ad iograph ic changes occur red soone r and to a m o r e severe degree w i th the roots con ta in ing e n d o t o x i n t h a n w i t h the roots con ta in ing saline solut ion. Histologic eva lua t i on s h o w e d grea te r per iapica l bone des t ruc t ion a n d a m o r e m a r k e d i n f l a m m a t o r y response . P o l y m o r p h o n u c l e a r l eukocytes w e r e the p r e d o m i n a t i n g cells. The resul ts of this s t udy indicate tha t endo tox in s m a y h a v e a role in per iapica l i n f l a m m a t i o n a n d b o n e des t ruc t ion .