Comparative Evaluation of the Characteristic Properties using FTIR Analysis and Degree of Conversion of Novel Nano-Filled Bulk Fill Flowable Composites for Dental Rehabilitation- An In Vitro Study

Abstract

To evaluate and compare the polymerisation efficiency of nano-filled bulk-fill flowable composites with conventional flowable composites using Fourier-transform infrared spectroscopy (FTIR), by determining the degree of conversion (DC) immediately after light curing and after 24 hours. Nano-filled bulk-fill flowable composite and conventional flowable composite specimens were prepared and light-cured according to a standardized protocol. Polymerisation efficiency was assessed using FTIR spectroscopy. The degree of conversion was determined immediately after polymerisation and after 24 hours by evaluating the reduction in aliphatic carbon–carbon double bonds (C=C). The DC values of the two composite groups were statistically compared, with the level of significance set at p < 0.05. The nano-filled bulk-fill flowable composite demonstrated significantly higher DC values than the conventional flowable composite both immediately after light curing and after 24 hours (p < 0.05). The improvement in polymerisation efficiency may be attributed to the nano-filled formulation and enhanced light transmission and distribution through the bulk of the restorative material. Within the limitations of this study, nano-filled bulk-fill flowable composites exhibited superior polymerisation efficiency compared with conventional flowable composites. The higher degree of conversion observed immediately and after 24 hours supports their potential use in thicker restorative increments and may contribute to improved clinical performance.