Influence of luting cement on the biomechanical behavior of Bioflx crowns

The objective of this study was to examine the impact of various types of cements on primary molar tooth restored with a Bioflx crown.

Three distinct finite element models were developed to represent three different cements; (1) conventional glass ionomer cement (GIC) (approximately 17 μm thick), (2) self-curing resin-modified GIC (RMGIC) (approximately 10 μm thick), and (3) self-cure resin cement (RC) (approximately 30 μm thick), all supporting/securing the Bioflx crown (approximately 330 microns thick). The geometry of the lower second primary molar was captured by laser scanning and then processed to create a solid model. This model was then imported into finite element software to assign materials, create a mesh, and evaluate stress and deformation under average normal occlusal loads. An applied load of 330 N was evaluated at three angles: vertical, oblique at 45°, and lateral.

The results indicated that model #2 (self-curing resin-modified GIC) exhibited the greatest deformation across all model components under the three loading conditions. The results for conventional GIC cement were comparable to those of self-cure resin cement. The resin-modified self-curing GIC (model #2) demonstrated high stress levels under lateral and oblique loads. Additionally, elevated stress concentrations were observed in the cortical bone region.

A cement type with a higher modulus of elasticity may be preferred over other types, in addition to the potential for use with a thinner thickness. Therefore, conventional GIC demonstrated the best performance among the cements evaluated in this study. This was followed by self-cure resin cement, while self-curing resin-modified GIC might be excluded due to expectation of failure.