Amalgam alternatives: Susceptibility of novel self-adhesive materials to changes in dentin mineralization

This study explores the effects of artificial de- and hypermineralization on the shear bond strength (SBS) of three innovative dental materials: a modern ion - releasing resin-based composite (Cention Forte (CF)), a resin-modified glass ionomer cement (Surefil One (SO)), and a high-viscosity glass ionomer cement (Equia Forte (EF)), all tested on human dentin.

A total of 360 human dentin specimens were divided into 18 groups (n = 20). Each material was bonded to either healthy, hypermineralized, or demineralized dentin. After aging at 37 °C in distilled water for 1 week and artificial saliva for 6 months, SBS was tested following ISO 29,022. Fracture origins and patterns were analyzed via light microscopy.

The SBS values of EF on hyper- and demineralized dentin were lower after 1 week and 6 months when compared to sound dentin, whereas for CF this trend was only seen on demineralized dentin after 1 week. Regardless of aging, the SBS values of SO displayed no significant difference in comparison to the reference. Across all substrates and aging types, the SBS values of CF were the highest. The long-term bond reliability of CF and EF on sound dentin was similar, as was the bond reliability of CF and SO on hypermineralized dentin.

CF produces the strongest bond to dentin irrespective of dentin substrate or aging. Demineralization deteriorates the bond strength of both CF and EF, whereas hypermineralization only that of EF. SO remains unaffected by changes in dentin mineralization, enabling it to form stronger bonds to hypermineralized dentin than EF.

A proper assessment of a material's bond strength to dentin substrates with varying degrees of mineralization is crucial for evaluating its potential as an effective amalgam replacement, capable of forming reliable bonds across a broad range of tooth substrates.