1. Dangers of using radiolucent dental materials;Drinnan;J Am Dent Assoc,1967
2. Clinical investigation of a radiopaque composite restorative material;Chandler;J Am Dent Assoc,1970
3. In vivo comparison of a composite resin and its radiopaque counterpart;Osborne;J Prosthet Dent,1978
4. Ryge, G., and Cvar, J. F.: Criteria for the clinical evaluation of dental restorative materials. United States Department of Health, Education, and Welfare; Public Health Service, National Institutes of Health, San Francisco, Calif.