Effects of repeated ingestion of large quantities of acetylsalicylic acid on membranous bone growth and dentin apposition in young monkeys.

Four daily doses of ASA were administered by mouth to young growing monkeys which received six injections of lead acetate every seven days as an intravital stain to indicate sites of bone and dentin mineralization. Microscopic evaluation of the inhibitory effects on membranous bone growth and dentin apposition was made. Four doses of ASA at 325 mg/kg inhibited membranous bone growth as well as the remodeling of the Haversian canal systems for about 16-18 days, with incomplete recovery during the experimental period. No comparable effect on dentinogenesis was observed. This preliminary study indicates that four doses of ASA at this level caused a toxic effect directly on membranous bone growth but not on dentin apposition.