Influence of different mould materials on the degree of conversion of dental composite resins

Abstract

AIM: In this study, the degree of conversion (DC) was analyzed on the surfaces of dental composite resins cured in different mould materials with different irradiation times. METHODS: Samples of three composite resins (Grandio®, Grandio Flow® [thickness = 2 mm; 4 mm; Ø = 5 mm] irradiated for 10 s, 20 s and 40 s and an experimental composite (EXPM) [thickness = 6 mm; Ø = 5 mm] irradiated for 40 s) were cured in moulds made of polytetrafluorethylene (PTFE), high-density polyethylene (HDPE) and stainless steel (SS). The DC was analyzed by FT-Raman spectroscopy. RESULTS: The DC was significantly lower for the 2-mm-thick samples of Grandio® cured with 20 s in the SS mould than in the PTFE mould. The same trend was found for the 4-mm-thick samples of Grandio Flow® cured with 40 s. The main difference of the DC between Grandio® and Grandio Flow® occurred when 10 s irradiation was used, independently of the mould material and thickness of the samples. The analysis of the DC on the sites around the samples of EXPM showed no significant difference from those at the bottom when cured in each mould material with 40 s irradiation. CONCLUSIONS: The DC was not affected by the mould material, instead, the resin formulation and the irradiation times were the main factors affecting the degree of conversion.

mould material; dental composite resin; degree of conversion; Raman spectroscopy

• ¹
  Zhu S, Tian Y, Hamielec AE, Eaton DR. Radical trapping and termination in free-radical polymerization of methyl methacrylate. Macromolecules. 1990; 23: 1144-50.
• ²
  Asmussen E. Factors affecting the quantity of remaining double bonds in restorative resin polymers. Scand J Dent Res. 1982; 90: 490-6.
• ³
  Pfeifer CS, Silva LR, Kawano Y, Braga RR. Bis-GMA co-polymerizations: influence on conversion, flexural properties, fracture toughness and susceptibility to ethanol degradation of experimental composites. Dent Mater. 2009; 25: 1136-41.
• ⁴
  Ruyter IE, Svendsen SA. Remaining methacrylate groups in composite restorative materials. Acta Odontol Scand. 1978; 36: 75-82.
• ⁵
  Zhu S, Tian Y, Hamielec AE, Eaton DR. Radical concentrations in free radical copolymerization of MMA/EGDMA. Polymer. 1990; 31: 154-9.
• ⁶
  Goncalves F, Pfeifer CC, Stansbury JW, Newman SM, Braga RR. Influence of matrix composition on polymerization stress development of experimental composites. Dent Mater. 2010; 26: 697-703.
• ⁷
  Amirouche-Korichi A, Mouzali M, Watts DC. Effects of monomer ratios and highly radiopaque fillers on degree of conversion and shrinkage-strain of dental resin composites. Dent Mater. 2009; 25: 1411-8.
• ⁸
  Furuse AY, Mondelli J, Watts DC. Network structures of Bis-GMA/TEGDMA resins differ in DC, shrinkage-strain, hardness and optical properties as a function of reducing agent. Dent Mater. 2011; 27: 497-506.
• ⁹
  Brandt WC, Schneider LF, Frollini E, Correr-Sobrinho L, Sinhoreti MA. Effect of different photo-initiators and light curing units on degree of conversion of composites. Braz Oral Res. 2010; 24: 263-70.
• ¹⁰
  Lopes MB, Moraes RR, Gonini-Junior A, Piva E. Impact of curing protocol on the selected properties of a model bis-GMA/TEGDMA dental resin composite. Biomed Mater. 2009; 4: 025014.
• ¹¹
  Moraes RR, Brandt WC, Naves LZ, Correr-Sobrinho L, Piva E. Light- and time-dependent polymerization of dual-cured resin luting agent beneath ceramic. Acta Odontol Scand. 2008; 66: 257-61.
• ¹²
  Chung KH, Greener EH. Correlation between degree of conversion, filler concentration and mechanical properties of posterior composite resins. J Oral Rehabil. 1990; 17: 487-94.
• ¹³
  Ferracane JL, Antonio RC, Matsumoto H. Variables affecting the fracture toughness of dental composites. J Dent Res. 1987; 66: 1140-5.
• ¹⁴
  Ferracane JL. Correlation between hardness and degree of conversion during the setting reaction of unfilled dental restorative resins. Dent Mater. 1985; 1: 11-4.
• ¹⁵
  Goncalves F, Kawano Y, Braga RR. Contraction stress related to composite inorganic content. Dent Mater. 2010; 26: 704-9.
• ¹⁶
  Dewaele M, Truffier-Boutry D, Devaux J, Leloup G. Volume contraction in photocured dental resins: the shrinkage-conversion relationship revisited. Dent Mater. 2006; 22: 359-65.
• ¹⁷
  Ferracane JL, Greener EH. The effect of resin formulation on the degree of conversion and mechanical properties of dental restorative resins. J Biomed Mater Res. 1986; 20: 121-31.
• ¹⁸
  Shin WS, Li XF, Schwartz B, Wunder SL, Baran GR. Determination of the degree of cure of dental resins using Raman and FT-Raman spectroscopy. Dent Mater. 1993; 9: 317-24.
• ¹⁹
  Miyazaki M, Onose H, Iida N, Kazama H. Determination of residual double bonds in resin-dentin interface by Raman spectroscopy. Dent Mater. 2003; 19: 245-51.
• ²⁰
  Soares LES, Martin AA, Barbosa Pinheiro AL. Degree of conversion of composite resin: a Raman study. J Clin Laser Med Surg. 2003; 21: 357-62.
• ²¹
  Tsuda H, Arends J. Raman spectroscopy in dental research: a short review of recent studies. Adv Dent Res. 1997; 11: 539-47.
• ²²
  Fan PL, Stanford CM, Stanford WB, Leung R, Stanford JW. Effects of backing reflectance and mold size on polymerization of photo-activated composite resin. J Dent Res. 1984; 63: 1245-7.
• ²³
  Harrington E, Wilson HJ. Depth of cure of radiation-activated materials-effect of mould material and cavity size. J Dent. 1993; 21: 305-11.
• ²⁴
  Gauthier MA, Stangel I, Ellis TH, Zhu XX. Oxygen inhibition in dental resins. J Dent Res. 2005; 84: 725-9.
• ²⁵
  International Organization for Standardization. IOf. ISO4049: 2000. Dentistry polymer - based filling, restorative and luting materials. ISO; 2000.
• ²⁶
  Ortengren U, Elgh U, Spasenoska V, Milleding P, Haasum J, Karlsson S. Water sorption and flexural properties of a composite resin cement. Int J Prosthodont. 2000; 13: 141-7.
• ²⁷
  Rueggeberg FA, Hashinger DT, Fairhurst CW. Calibration of FTIR conversion analysis of contemporary dental resin composites. Dent Mater. 1990; 6: 241-49.
• ²⁸
  Stansbury JW, Dickens SH. Determination of double bond conversion in dental resins by near infrared spectroscopy. Dent Mater. 2001; 17: 71-9.
• ²⁹
  Emami N, Soderholm KJ, Berglund LA. Effect of light power density variations on bulk curing properties of dental composites. J Dent. 2003; 31: 189-96.
• ³⁰
  Goncalves F, Calheiros FC, Witzel MF, Kawano Y, Braga RR. Effect of photoactivation protocol and radiant exposure on monomer conversion and flexural strength of a resin composite after water and ethanol storage. J Biomed Mater Res B Appl Biomater. 2007; 82: 89-92.
• ³¹
  Emami N, Soderholm KJ. How light irradiance and curing time affect monomer conversion in light-cured resin composites. Eur J Oral Sci. 2003; 111: 536-42.

Publication Dates

• Publication in this collection
  04 June 2013
• Date of issue
  Dec 2012

History

• Received
  11 July 2012
• Accepted
  10 Dec 2012