Effect of preheating and ultrasonic energy on penetration of low viscosity enamel resin infiltrant

Abstract

Objectives: to determine the depth of resin infiltrated hybrid enamel after application of TTEMA/TEGDMA resin infiltration agent enriched with nano-hydroxy apatite applied on early carious enamel lesions.Materials and Methods: Sound maxillary centrals were coated with a nail varnish, leaving a window of 4 mm × 4 mm on buccal surface of sound and intact enamel. All specimens were subsequently immersed in a demineralizing solution to produce artificial enamel lesions then etched with a mixture of 2% chlorhexidine and 10% hydrochloric acid. After washing and drying the enamel was coated with a low viscosity TTEMA/TEGDMA resin infiltration agent followed by light polymerization. The effect of addition of 10% nano-hydroxy apatite, preheating at 45oC, and ultrasonic activation was tested in separate groups. Sectioned specimens were examined under a stereomicroscope equipped with a high-resolution digital camera for determining of the depth of penetration of the low viscosity resin in microns (α=0.05).Results: Data analysis revealed significant difference in depth of enamel hybrid layer between the tested groups (F=14.2, P<0.001). Average penetration depth was 185 ± 17 µm for TTEMA/TEGDMA resin infiltration agent. Addition of 10% nano-hydroxy apatite reduced penetration depth to 141± 19 µm. On the contrary, preheating and ultrasonic activation increased penetration depth to 211± 13 µm and 221 ± 12 µm respectively.Conclusions: Within the limitations of this study, the penetration depth of TTEMA/TEGDMA resin infiltration agent was significantly influenced by addition of nano-hydroxy apatite particles. Preheating and ultrasonic activation increased penetration depth significantly.