Thermal, Mechanical, Chemical, Elemental, Optical and Surface Characterization of Different Twinky Star^® Colored...

Colored compomers are widely used in pediatric restorative dentistry because their visual attractiveness may improve patient acceptance and cooperation. Although different color variants are often regarded as purely aesthetic modifications, pigments and decorative fillers may influence polymerization, heat generation, mechanical performance, and surface properties. This study evaluated the thermal, mechanical, chemical, elemental, optical, and surface characteristics of four Twinky Star^® compomer shades (Blue, Gold, Lemon, and Silver) compared with two commonly used tooth-shaded resin composites, Boston A3 and Charisma A2. Thermographic analysis determined maximum temperature, temperature increase, time above 40 °C, and thermal exposure above 40 °C. Mechanical properties were assessed by instrumented indentation, morphology and elemental composition by SEM/BSE and EDS, chemical characteristics by ATR-FTIR spectroscopy, optical properties by spectrophotometry, and surface characteristics by contact angle measurements. Pronounced differences among the Twinky Star^® color variants were observed. Blue showed the lowest thermal response, whereas Lemon exhibited the highest thermal exposure. Gold demonstrated the weakest mechanical performance, while Silver showed the most favorable mechanical profile. EDS revealed quantitative differences in Ba, Sr, F, and Si, whereas ATR-FTIR confirmed a comparable chemical matrix among color variants. These findings indicate that Twinky Star^® color variants should not be considered solely aesthetic alternatives, as shade-associated compositional and optical differences may be accompanied by differences in material performance.