Long-term optical and physical stability of resin composites: the role of MDP-containing adhesive as a modeling...

To evaluate how a modeling liquid and an MDP-containing adhesive affect the surface roughness, water sorption/solubility, and optical stability of a nano-hybrid resin resin composite.

A nano-hybrid resin composite was divided into three groups: control (no modeling agent), GC Modeling Liquid (ML), and Clearfil SE Bond (SB). Surface roughness (Ra) was measured before and after simulated brushing. Water sorption and solubility were tested per ISO 4049. Color stability and translucency were measured spectrophotometrically at baseline and after 1, 7, and 28 days of immersion in staining solutions. Data were analyzed using appropriate statistical tests (p < 0.05).

The tested modeling agents reduced initial surface roughness; however, this advantage was lost after brushing. While water sorption was similar across groups, the SB group showed significantly lower solubility. After 28 days, both ML and SB groups resisted coffee staining. In red wine, the SB group exhibited superior color stability and, unlike others, showed no significant loss of translucency.

The chemical composition of a modeling agent appears to be more critical for long-term stability than its initial effect on surface texture. The tested MDP-containing adhesive formulation may contribute to reduced solubility and improved optical stability under the conditions of this study.

The selection of a modeling agent based on its chemical composition, rather than handling alone, is a key strategy. An MDP-containing adhesive improves the long-term optical integrity and durability of restorations, especially in challenging clinical situations.