Preparation of a novel anti shrinking agent (SOC DA) and its evaluation in dental resins
- PDF / 685,744 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 68 Downloads / 274 Views
Preparation of a novel anti shrinking agent (SOC DA) and its evaluation in dental resins Ricardo Acosta Ortiz*, Luis Alberto Reyna Medina*, María Lydia Berlanga Duarte, Aida Esmeralda Garcia Valdez Centro de Investigación en Química Aplicada, Blvd. Enrique Reyna No. 140 Saltillo Coahuila; México 25294. Tel 52 844 4389844, email*: [email protected], [email protected] Abstract In this work is discussed the synthesis of a novel antishrinking agent (SOC DA) and the evaluation of its performance in an acrylic dental resin. SOC DA was photopolymerized in conjunction with the components of a conventional acrylic resin, which includes a mixture of diacrylate monomers [glycerolate bisphenol A dimethacrylate (BIS-GMA) / Urethane dimethacrylate (UDMA) / triethyleneglycol dimethacrylate (TEGDMA)] in 50/30/20 molar ratio). SOC DA was added in a range between 5.0-20.0 mol % with respect to the total amount of moles of the acrylic monomers. It was found that increasing concentrations of SOC DA, promoted higher conversions of the dimethacrylate monomers without decreasing the photopolymerization rate of the acrylate monomers. The study of the effect of SOC DA on the mechanical properties of the dental composite filled with 70 % of silicon dioxide, revealed that the presence of the antishrinking agent improved both the compressive and the flexural strength of the dental materials. Besides, it was found that by using the SOC DA at 20%, the shrinkage was reduced 52%, compared with the same formulation without SOC DA. 1. Introduction To date, dental acrylic resins have gained wide acceptance, because of the improved aesthetics and functionality of the teeth, in comparison with amalgams. However, one of their drawbacks is the shrinkage that is produced during the photopolymerization. This may lead to problems such as microleakages, which in turn, can cause secondary caries and sensitivity. One of the approaches used to solve this problem is the use of spiroorthocarbonates (SOCs). These SOC monomers undergo expansion during polymerization as a result of the double ring opening polymerization1. Several studies concerning the use of SOCs in dental resins have been reported2,3 In this study we describe the synthesis of a novel antishrinking agent which comprises a mixture of diallylic spiroorthocarbonates, and the study of its effect on the photopolymerization rate, viscoelastic and mechanical properties. Besides, it is also reported its efficiency to reduce the shrinkage in the composited dental material.
2. Experimental Details 2.1. Synthesis of SOC DA In a three-necked round-bottomed flask provided with thermometer, magnetic stirring and nitrogen inlet were placed 4.291 g. (0.022 mol) of SOC DIOL3, 50 mL of dried toluene , and 8.932 g. (0.223 mol) of NaOH. The reaction mixture was kept stirred by 5 minutes and then was added 23.634 mL (0.223 mol) of allyl bromide, and 0.719 g (0.002 mol) of tetrabutyl ammonium bromide. The mixture was refluxed for 28 hours under nitrogen atmosphere and then allowed to cool. After filt
Data Loading...
