# Effect of the Silanization of Aerosil OX50 in the Properties of Light-Cured Dental Composites
97205, Yucat, Mexico; [EMAIL_ADDRESS] (W.H.-K.); [EMAIL_ADDRESS] (J.V.C.-R.); [EMAIL_ADDRESS] (J.M.C.-U. ); [EMAIL_ADDRESS] (J.M.C.-U. ); [EMAIL_ADDRESS] (J.M.C.-U.) 3  
Veraes-Panuela  
1 Centro de Biomateriales, Universidad de La Habana, Ave. Universidad, e/Ronda y G, Plaza de la Revolucion, La Habana C.P. 10400, Cuba; seele20 [EMAIL_ADDRESS] (S.d.l.C.D.-R.); [EMAIL_ADDRESS] (O.T.-A. ); [EMAIL_ADDRESS] (A.A.L.S.) 2 Centro de Investigacion Cientifica de Yucat (CICY), Calle 43, No. 130 x 32 y 34, Col. Chuburna de Hidalgo, Merida C.P. 97205, Yucat, Mexico; [EMAIL_ADDRESS] (W.H.-K.-K.); [EMAIL_ADDRESS] (J.V.C.-R.); [EMAIL_ADDRESS] (J.M.C.-U. ); [EMAIL_ADDRESS] (J.M.C.-U. ); [EMAIL_ADDRESS] (J.M.C.-U. ); [EMAIL_ADDRESS] (J.M.C.-U. ); [EMAIL_ADDRESS] (J.M.C.-U.) 3  
Veraes-Panuela  
1 Centro de Investigacion Cientifica de Yucat (CICY), Calle 43, No. 130 x 32 y 34, Col. Chuburna de Hidalgo, Merida C.P. 97205, Yucat, Mexico; [EMAIL_ADDRESS] (W.H.-K.); [EMAIL_ADDRESS] (J.V.C.-R.); [EMAIL_ADDRESS] (J.M.C.-U. ); [EMAIL_ADDRESS] (J.M.C.-U. reduction of microleakage, and prevention of postoperative sensitivity. In general, composite resins or dental composites are made up of a mixture of acrylic monomers made up of an organic matrix, filler particles, a coupling agent, whose function is to achieve an optimal bond between both components, and an initiator system [5]. The organic matrix of dental composite resins is basically made up of two types of monomers that are divided according to their viscosity into base monomers and diluents. 2,2 [p-(2-hydroxy-3-methacryloxypropoxy) phenyl] propane (Bis-GMA) is the most commonly used base monomer for this purpose due to its properties such as low shrinkage upon polymerization, rigidity, and high resistance [6]. However, it has a high viscosity that negatively affects the final properties of the composite, requiring the use of diluent monomers such as tri- and tetraethylene glycol dimethylacrylates (TEGDMA and TEEGDMA, respectively) [7]. Quartz, glass, titanium oxide, and silicon oxide are generally used as inorganic fillers, providing an increase in the resistance to traction, compression, and abrasion of composites. Hydroxyapatite could be a promising bioactive filler for dental resin composites, since it is the main biological component of dentin and enamel [8,9]. In addition to reducing shrinkage in composites it is desirable that mechanical properties are like that of the dental structure in order to guarantee a restoration that meets physical, chemical, and mechanical needs, i.e., an aesthetic and biocompatible dental composite. Currently, there is a trend to use nanofillers to obtain composite resins with dental applications, since these improve the wear properties of the composites, such is the case of aerosil OX50. This is a fumed silica made up of spherical particles of 40 nm in diameter. This silica is obtained by flame hydrolysis of silicon tetrachloride, SiCl\({}_{4}\)[10,11]. Among the most important properties of dental resins for clinical use are the degree of conversion, water sorption and solubility, and the mechanical properties. The values required for these properties are well known and have been established in various international standards [12]. The degree of conversion of the composites expresses the number of double bonds of the methacrylate monomeric groups that react. It can be determined by infrared spectroscopy, considering the decrease in the intensity of the absorption band of the double bonds corresponding to the aliphatic carbons [9]. The depth of cure is also a property that indicates the effectiveness of the polymerization process and is carried out according to the stablished parameters in the ISO 4049 standard [12,13]. Other properties that are evaluated and regulated (ISO 4049) are water sorption and solubility.