Influence of Water Absorption on Polymerization Shrinkage Stresses in Dental Resin Cements
Dr. Agata Szczesio-Włodarczyk1, Prof. Jerzy Sokołowski2, Dr. Michał Krasowski1, Asst. Prof. Kinga Bociong2
1 University Laboratory of Materials Research, Medical University of Lodz,
2 Department of General Dentistry, Medical University of Lodz
Objectives
Self-adhesive cements simplify the process of bonding prosthetic restoration by eliminating the need for additional treatments. However, conventional adhesion is preferred for low-retention restorations. New universal cements offer a versatile solution, serving as both self-adhesive and conventional adhesive luting material when combined with a tooth primer.
Materials and Methods
The study examined the shrinkage stresses generated during polymerization by new universal adhesive cements with total-etch adhesive (Nexus Universal, G-CEM One) compared to adhesive (NX3, Variolink Esthetic), adhesive resin with self-etch primers (Multilink Automix, Panavia 2.0), and self-adhesive cements (Breeze, MaxCem Elite). The influence of the aqueous environment on the stress state was determined, as well as the adsorption of water by the tested materials. The stress state was measured using photoelastic analysis. To characterize absorbency dynamic changes in samples’ weight during the water conditioning were determined.
Results
The lowest contraction stress from tested materials exhibited Panavia 2.0 (5.8±0.9 MPa) while Variolink Esthetic and Multilink Automix obtained the highest values around 12 MPa. All studied materials exhibited contraction stress relief during water immersion (84 days) due to hygroscopic expansion. Breeze exhibited the highest absorption (3.2±0.3 %) and caused the highest stress values due to water expansion (from 0 to almost 5.4 MPa).
Conclusions
Despite relatively high absorption values, new universal resin cements did not show hygroscopic expansion stress.