## 1 _Article_  
Evaluation of Smart Chromatic Technology for a Single-Shade Dental Polymer Resin: An In Vitro Study  
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a difficult task [1]. Among the many restorative materials, resin-based materials have displayed some of the best outcomes clinically. Resin composites have been proven to be excellent tooth replacement materials and a great choice for a plethora of clinical indications due to their good adhesive bonding, aesthetics, translucency, mechanical properties, and biocompatibility [2,3]. Many dentists struggle when matching the shade of a tooth with that of the desired restorative material. A demarcation always remains between the two entities, which is known as the blending effect (BE) [4]. In the literature, this is explained as an evident demarcation of the restoration from the tooth structure under isolation [5]. However, the blending effect in shaded resin composites is influenced by the restoration size, as the BE for fillings increases with decreasing restoration size and increasing filling material translucency. Moreover, BE increases when the color difference between the restoration and the surrounding walls decreases [5,6]. To avoid this problem, many dentists use a mixture of resin composite shades, employing a layering technique. Moreover, the optical properties also play an important role in the appearance of a restoration. The illumination, translucency, opacity, light scattering, gloss, and human sensitivity influence the overall perception of tooth color [7,8]. Teeth are made up of layers called enamel and dentin, which differ in terms of their structural characteristics and optical properties [8]. Both exhibit different light wave characteristics, which reflect upon the appearance of the teeth [9]. Due to its highly mineralized prismatic structure, low organic content, and small amount of water, higher transmission of light occurs with enamel than dentin. In contrast, dentin has a lower mineral content, with an organic tubular structure, low translucency, and a high water content [10]. The light reflection and transmission of modern resin-based restorative materials used for tooth structure repair are influenced by the materials' organic and inorganic constituents and proportions [11,12]. One ideal standard is to develop advanced restorative materials with properties similar to the tooth structure. The aim is to simulate the natural tooth in terms of color, translucency, and surface texture in order to achieve long-term color stability. In recent times, resin-based materials have shown improved physical, mechanical, and optical properties. However, resin composites are low in biomimetic potential due to their non-crystalline structures, low translucency, and absence or presence of fluorescence [13,14]. These characteristics and others make color matching between the resin composite and the tooth structure much more difficult to achieve [15,16]. In recent times, a novel single-shade resin restorative composite (Omnichroma (OM)) was designed using smart chromatic technology, with 260 nm spherical fillers and a similar appearance as the surrounding tooth structure [17]. OM is available as a single-color universal composite and was designed for use in most direct restorative clinical cases. Its wide color matching ability eliminates the need for a shade assessment procedure and reduces the composite inventory, allowing clinicians to minimize chair time, the wastage of unused composite shades, and to reduce reliance on shade matching procedures.