Amorphous Macromers as Potential Organic Matrix in Dental Composites

Objectives: Assess the thermal and hydrolytic stability of patented macromer- based dental polymer matrices and composites

Methods: Polymer matrices and composites based on a patented material (IP:343192) containing hybrid amorphous macromers co-polymerized with one of the 4 different dimethacrylates was prepared and the thermal and photo-thermal behavior were assessed. Diffusivity resistance and cross-link density of polymers were assessed. Sorption (𝑆(𝑡), 𝑀𝑔%(𝑡) 𝖠 𝑆%(𝑡)and solubility (𝑆𝐿(𝑡) 𝖠 𝑆𝐿%(𝑡) of composites in chloroform (CHCl3), tetrahydrofuran (THF), carbon tetrachloride (CCL) and acetone (Ace) for varying durations (1h, 24h 1mo), and deionized water for 120h were determined.

Results: Dual T_g were noticed for both the matrices and composites; matrices containing BisGMA (G) and UDMA (U) as the dimethacrylate co-polymer showed significantly lower𝑆𝐿(𝑡). Matrix containing TEGDMA (T) as the dimethacrylate co-polymer showed the least 𝑆(𝑡). Matrix containing BisEMA (E) had the highest cross-link density. photo-DSC of composites showed a Degree of Conversion of 97% at lower enthalpies (15-28J/g). None of the composites showed water solubility. All materials showed solubility in acetone with U being the least. Sorption and solubility in other organic solvents was lower and occurred only at longer immersion time.

Conclusions: Amorphous hybrid macromer-based polymer matrices and composites show promising thermal and hydrolytic behavior.