Synthesis and polymerization of new expanding dental monomers

The objective of this work was to develop polymeric materials that expand slightly upon polymerization and that could potentially be used as matrix resins for dental composites. A series of stereoisomeric alicyclic spiroorthocarbonates (SOC's) that expand when polymerized were synthesized. Three of these SOC racemates were analyzed: cis/cis-, cis/trans- and trans/trans-2,3,8,9-di(tetramethylene)-1,5,7,11-tetraoxaspiro[5.5] undecane. The degrees of expansion, approximately 3.9% and 3.5%, for the cis/cis and trans/trans, were determined by measuring the specific volume of the monomers and polymers in dilute solutions. This method of determining densities and subsequent calculated expansion or shrinkage was validated by duplicating the reported shrinkage of 4-tert-butylphenyl glycidyl ether, styrene, and methyl methacrylate. Based on these data and spectral data obtained using other analytical techniques, these stereoisomeric alicyclic SOC's appear to have potential as nonshrinking polymer or copolymer matrices for dental composites.