Related Experiment Video
Updated: May 27, 2026
Shrinkage of Dental Composite in Simulated Cavity Measured with Digital Image Correlation
Published on: July 21, 2014
Structure-property relationship in new photo-cured dimethacrylate-based dental resins
1Faculty of Chemistry, Department of Polymer Chemistry, MCS University, Lublin, Poland. m.podgorski@op.pl
Objectives:
In this study five novel dimethacrylates of different chain lengths having rigid aromatic rings were synthesized and proposed as possible dental monomers for dental resin mixtures.
Methods:
Four monomers were prepared by the reaction of glycidyl methacrylate with dicarboxylic acid esters obtained from phthalic anhydride and 1,3-propylene, 1,4-butylene, 1,5-penthylene and 1,6-hexylene glycols. The addition reaction of glycidyl methacrylate and the acidic compound was carried out in the presence of tetraethylammonium bromide. The fifth monomer was obtained from 1,5-penthylene glycol-based dimethacrylate by blocking its hydroxyl groups with acetyl groups. The monomers were photo-copolymerized with triethyleneglycol dimethacrylate (TEGDMA) in the presence of a photoinitiator which was 2,2-dimethoxy-2-phenyloacetophenone. Unfilled polymers were evaluated for photopolymerization conversion and volumetric curing shrinkage. Water sorption, water solubility, flexural strength and hardness were measured. The prepared polymers were also subjected to dynamic mechanical studies (DMA).
Results:
Results show that, increasing the distance between double bonds decreases flexural modulus and hardness. As expected, the curing shrinkage increased with increasing degree of conversion. The acetylation of hydroxyl groups resulted in improved water uptake properties of the compositions. It was demonstrated that, depending upon the content of acetyl groups in the network, the glass transition temperature may be significantly lowered. In polymers with large amounts of pendant groups, β relaxation overlaps with α relaxation (glass transition temperature), and it is the former that discloses the maximum on the tanδ curve.
Significance:
The systematic change in the length of the new dimethacrylates provided insight into the effects on the resultant material properties. It was shown in the article that the properties of the new monomers compare favorably with properties of the commercially available resins.
Related Concept Videos
01:17Mortar Properties
01:28Structures of Carboxylic Acid Derivatives
Carboxylic acid derivatives contain an acyl group attached to a heteroatom such as chlorine, oxygen, or nitrogen. The carbonyl carbon and oxygen are both sp2-hybridized with an unhybridized p orbital.
The three sp2 orbitals of the carbonyl carbon form three σ bonds, one each with the carbonyl oxygen, the α carbon, and the heteroatom, whereas the other two sp2 orbitals of the carbonyl oxygen are occupied by the lone pairs. Further, the unhybridized p...