Introduction to the Symposium Presented at the 1988 Annual Meeting of The society of Toxicology

The 1976 amendments to the Faxi, Drug, and Cosmetic Act establishedrequirements for obtaining approval to market new medical devices,including the necessity for demonstrating safety and effectiveness.Evaluation of the potential toxicity of medical devices presentstoxicologists with unique problems related to route of exposure,estimation of exposure dose, exposure to by-products generatedduring manufacture, and matrix effects. A symposium was organizedto address the need for toxicologists to examine the potentialtoxicities of medical device materials, to appreciate the uniqueproblems associated with medical device safety evaluation, topresent novel testing methodologies, and to discuss future researchneeds.     

The ability of the radiograph to determine the location of the apical foramen

An in-vitro radiographic study of human teeth was performed in order to evaluate the ability of radiographs to determine the location of the apical foramen. The tip of an endodontic file was positioned at the apical foramen of each canal in 117 extracted human teeth (213 canals) and in 56 teeth (92 canals) still within the alveolus of dried jaw specimens. Parallel radiographs were taken in a bucco-lingual plane of all teeth. The tip of the instrument appeared to be at the root surface (apical foramen) in 82 per cent of canals. There was no significant difference in results between the teeth radiographed in the alveolus of dried jaw specimens and extracted teeth when the radiographs were evaluated under a stereomicroscope.