Monomer Effect on Mechanical Properties of Pit-and-Fissure Sealants with Microcapsules

Objectives: The objective of this study was to determine the effect of continuous phase monomer on flexural strength and bond strength to enamel of pit-and-fissure sealants formulated with microencapsulated remineralizing agents.
Methods: A heterogeneous polymerization technique was utilized to prepare microcapsules containing aqueous solutions of 0.8M NaF, 5M Ca(NO₃)₂ and 3M K₂HPO₄. These microcapsules were formulated into pit-and-fissure sealants that differed by the types of monomers used for the continuous phase. The monomers used in the formulations were bisGMA, UDMA, an aliphatic urethane methacrylate and TEGMA. In these formulations, the microcapsules were loaded 5w/w% (2w/w% of aqueous fluoride solution, 2w/w% of aqueous calcium solution and 1w/w% of aqueous phosphate solution). Flexural strength was assessed using specimens with a 2mm x 2mm x 20mm geometry in 3-point bend (n=12). Shear bond strength (SBS) to intact bovine enamel was determined by preparing bonded assemblies using an Ultradent fixture and loading to failure (1.0 mm/min) after 7 days of water storage at 37⁰C.
Results: Flexural strength and bond strength to enamel were measured. A table highlighting some of the results is shown below.
Conclusions: Mechanical properties were measured for sealants formulated with microencapsulated remineralizing agents. The preparation of formulations with bisGMA lead to enhanced mechanical properties. This work is funded in part by Premier Dental Products Incorporated.