Comparison of Material Properties of Commercial and Keto-Coumarin Containing Sealants

Objectives: To compare the material properties of a commercial dental sealant (Clinpro Sealant, 3M) with a prototype sealant containing an experimental keto-coumarin photo-initiator.
Methods: Barcol hardness, degree of conversion (FTIR), and wear testing (ElectroForce 3300) were measured for both Clinpro Sealant and the keto-coumarin containing prototype. The prototype formulation contains 0.30 wt% of the keto-coumarin photo-initiator (CAS: 115948-29-3), 0.30 wt% of Iodonium Salt (CAS: 58109-40-3), and 0.70 wt% of N-Phenylglycine (CAS: 103-01-5).
Results: The results showed comparable Barcol hardness values for Clinpro Sealant (Top/Bottom: 43/36) and the keto-coumarin containing sealant prototype (Top/Bottom: 43/37). However, degree of conversion (DOC) was not comparable with Clinpro Sealant having a DOC of 46.4%, while the keto-coumarin sealant prototype had a DOC of 69.8%. Also, Clinpro Sealant had a wear depth of 107 µm under 30 newtons of pressure for 5000 cycles and the keto-coumarin containing sealant prototype had a wear depth of 30 µm under the same conditions.
Conclusions: These results somewhat matched the expected observations that the two sealants would perform comparably in non-product specific categories. However, it can be generally determined that the keto-coumarin sealant prototype performed better in the chosen tests then the commercial dental sealant. This may have been due to a variety of factors such as filler size and initiator concentrations.