RADIOPAQUE RESTORATIVE AND PROSTHETIC DENTAL RESINS

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Polymer resins used to fabricate dental and medical prostheses and dental restorations are generally radiolucent. Thus they are difficult to locate when accidently or purposely introduced into the body. Therefore accidents pose a hazard to patients and often lead to several medical emergencies and occasionally death, while in every case radiographic diagnosis is difficult. The seriousness of these problems is becoming ever more widely recognized. Currently, radiopacity is accomplished with metal or heavy-metal salts or galsses. These additives weaken the mechanical integrity because of the disparity between the low polarity of a hydrophobic resin and the high polarity or ionic and metallic additives. It is proposed that lthis problem can be solved by incorporating neutral ligands which are strongly complexed with a heavy-metal ion such as Ba, thus solubilizing a metal salt in the resin and forming a homogenous structure that retains mechanical strength and resists liquid penetration. The macrocyclic "crown" ethers and "glymes", and the polyphosphonate esters are proposed as the chelating species to be investigated for carrying radiopaque salts. The study will be a collaboration between polymer scientists at S.U.N.Y., Syracuse, and Biomaterials, radiology, microbiology and tissue-culture scientists at L.S.U. School of Dentistry in New Orleans. The chelating polymers will be synthesized at S.U.N.Y., under separate grant support, and supplied to L.S.U. where they will be formulated as prosthetic and restorative resins and evaluated for radiodensity, mechanical integrity, and probable biological safety. Radiodensity will be determined by film densitometry of x-ray images of trial specimens. Mechanical integrity will be determined using tests and standards specified by American Dental Society specifications for restorative and prosthetic resins. Probable safety will be assessed using the Ames mutagenicity test and tissue culture cytotoxicity techniques developed at LSU. Funding is being sought via two companion applications. Each have identical research plans but different institutional information and budget requests. The budget requestin in this application is designed to completely support that part of the proposed investigation that is to be performed by the L.S.U. group.