Effect of Preheating on the Mechanical Properties of Resin Composites

ABSTRACT

Objectives: The purpose of this study was to compare the flexural strength and modulus of two commercial resin composites, at room temperature and 40, 45 and 50�C prior to light polymerization with standard and step-cure protocols.

Methods: One nanohybrid (Grandio, VOCO, Cuxhaven, Germany), and microhybrid compositeresin (Filtek Z250, 3M ESPE, St. Paul, MN, USA) were used. The materials were inserted into rectangular moulds at room temperature or preheated to a temperature of 40, 45 or 50°C and cured with standard or step-cure protocols with high intensity halogen (Elipar Highlight, 3M-ESPE, St. Paul, MN, USA). Ten specimens were prepared for each preheating and light curing protocol. A three-point bending test was performed using a universal testing machine at a crosshead speed of 1 mm/min. The data were analyzed by one-way analysis of variance and Tukey’s post hoc tests (P<.05) to examine the effect of curing protocol and preheating. Pearson’s correlation test was used to determine the correlation between tested mechanical properties and preheating.

Results: There were no statistically significant difference between tested mechanical properties of the materials, curing protocols and temperature of the materials. No significant correlation was found between preheating and tested mechanical properties.

Conclusions: The mechanical properties of the tested materials did not changed by preheating so the tested materials could be preheated because of the other potential clinical advantages like more adaptation to the cavity walls. (Eur J Dent 2008;2:263-268)

Key Words:

Resin composite - Preheating - Polymerization

• REFERENCES

• 1 Manhart J, Kunzeimann KH, Chen HY, HickeL R. Mechanical properties and wear behavior of light cured packable composite resins. Dent Mater 2000; 16: 33-40
• 2 Poss SD. Using a new condensable composite for posterior restorations. Compend Contin Educ Dent Suppl 1999; 23: 14-18
• 3 Al-Sharaa KA, Watts DC. Stickiness prior to some light cured resin composites. Dent Mater 2003; 19: 182-187
• 4 Blalock JS, Holmes RG, Rueggeberg FA. Effect of temperature on unpolymerized composite resin film thickness. J Prosthet Dent 2006; 96: 424-432
• 5 Rodrigues Junior SA, Zanchi CH, Carvalho RV, Demarco FF. Flexural strength and modulus of elasticity of different types of resin based composites. Braz Oral Res 2007; 21: 16-21
• 6 Crim G, Chapman KW. Reducing microleakage in Class II restorations: an in vitro study. Quintessence Int 1994; 25: 781-785
• 7 Schuckar M, Geurtsen W. Proximo-cervical adaptation of Class II composite restorations after thermocycling: a quantitative and qualitative study. J Oral Rehabil 1997; 24: 766-775
• 8 Freedman PD. Clinical benefits of pre-warmed composites. Private Dent 2003; 8: 111-114
• 9 Friedman J. Thermally assisted polymerization of composite resins. Contemp Esthetics Rest Practice 2003; 7: 46
• 10 Roeters JJ, Shortall AC, Opdam NJ. Can a single composite resin serve all purposes?. Br Dent J 2005; 199: 73-79
• 11 Powers JM, Wataha JC. Dental materials: properties and manipulation. St. Louis: Elsevier; 2003: 68-72
• 12 Hervas-Garcia A, Martinez-Lozano Ma, Cabanes-Vila J, Barjau-Escribano A, Fos-Galve P. Composite resins: a review of the materials and clinical indications. Med Oral Patol Oral Cir Bucal 2006; 11: E215-220
• 13 Bagis YH, Rueggeberg FA. Effect of post cure temperature and heat duration on monomer conversion of photoactivated dental resin composite. Dent Mater 1997; 13: 228-232
• 14 Park SH, Lee CS. The difference in degree of conversion between light-cured and additional heat-cured composites. Oper Dent 1996; 21: 213-217
• 15 Trujillo M, Newman SM, Stransbury J. Use of near-IR to monitor the influence of external heating on dental composite photopolymerization. Dent Mater 2004; 20: 766-777
• 16 Daronch M, Rueggeberg FA, De Goes MF. Monomer conversion of pre-heated composite. J Dent Res 2005; 84: 663-667
• 17 Daronch M, Rueggeberg FA, De Goes MF, Giudici R. Polymerization kinetics of pre-heated composite. J Dent Res 2006; 85: 38-43
• 18 Roulet JF. The problems associated with substituting composite resins for amalgam: a status report on posterior composites. J Dent 1988; 16: 101-113
• 19 Craig RG. Restorative dental materials. St. Louis: Mosby Publishing Co; 1997
• 20 Lovell LG, Lu H, Elliott JE, Bowman CN. Understanding the kinetics and network formation of dimethacrilate dental resins. Polym Adv Technol 2001; 12: 335-345
• 21 Munoz CA, Bond PR, Sy-Munoz J, Tan D, Peterson J. Effect of pre-heating on depth of cure and surface hardness of light-polymerized resin composites. Am J Dent 2008; 21: 215-222
• 22 Lovell LG, Lu H, Elliot JE, Stansbury JW, Bowman CN. The effect of cure rate on the mechanical properties of dental resins. Dent Mater 2001; 17: 504-51
• 23 Prasanna N, Pallavi Reddy Y, Kavitha S, Lakshmi Narayanan L. Degree of conversion and residual stress of preheated and room-temperature composites. Indian J Dent Res 2007; 18: 173-176
• 24 Daronch M, Rueggeberg FA, Hall G, De Goes MF. Effect of composite temperature on in vitro intrapulpal temperature rise. Dent Mater 2007; 23: 1283-1288
• 25 Daronch M, Rueggeberg FA, Moss L, De Goes MF. Clinically relevant issues related to preheating composites. J Esthet Restor Dent 2006; 18: 340-351
• 26 Loughran GM, Versluis A, Douglas WH. Evaluation of sub-critical fatigue crack propagation in a restorative composite. Dent Mater 2005; 21: 252-261
• 27 Della Bona A, Anusavice KJ, DeHoff PH. Weibull analysis and flexural strength of hot-pressed core and veneered ceramic structures. Dent Mater 2003; 19: 662-669
• 28 International Organization for Standardization ISO 4049/ 2000-Dentistry-Polymer-based filling, restorative and luting materials. Switzerland: ISO; 2000
• 29 Chung SM, Yap AUJ, Chandra SP, Lim CT. Flexural strength of dental composite restoratives: comparison of biaxial and three-point bending test. J Biomed Mater Res B Appl Biomater 2004; 71: 278-283
• 30 Palin WM, Fleming GJ, Marquis PM. The reliability of standardized flexure strength testing procedures for a light-activated resin-based composite. Dent Mater 2005; 21: 911-919
• 31 Sabbagh J, Vreven J, Leloup G. Dynamic and static moduli of elasticity of resin-based materials. Dent Mater 2002; 18: 64-71
• 32 Xu HHK, Smith DT, Jahamir S, Romberg E, Kelly JR, Thompson VP, Rekow ED. Indentation damage and mechanical properties of human enamel and dentin. J Dent Res 1998; 77: 472-480
• 33 St Germain H, Swartz ML, Phillips RW, Moore BK, Roberts TA. Properties of microfilled composite resins as influenced by filler content. J Dent Res 1985; 64: 155-160
• 34 Li Y, Swartz ML, Phillips RW, Moore BK, Roberts TA. Effect of filler content and size on properties of composites. J Dent Res 1985; 64: 1396-1401
• 35 Braem M, Finger WJ, Van Doren VE, Lambrechts P, Vanherle G. Mechanical properties and filler fraction of dental composites. Dent Mater 1989; 5: 346-349
• 36 Chung KH. The relationship between composition and properties of posterior resin composites. J Dent Res 1990; 69: 852-856
• 37 Chung KH, Greener EH. Correlation between degree of conversion, filler concentration and mechanical properties of posterior composite resins. J Oral Rehabil 1990; 17: 487-494
• 38 Gladys S, Van MB, Braem M, Lambrechts P, Vanherle G. Comparative physico-mechanical characterization of new hybrid restorative materials with conventional glass- ionomer and resin composite restorative materials. J Dent Res 1997; 76: 883-894
• 39 Kim KH, Ong JL, Okuna O. The effect of filler loading and morphology on the mechanical properties of contemporary composites. J Prosthet Dent 2002; 87: 642-649
• 40 Beun S, Glorieux T, Devaux J, Vreven J, Leloup G. Characterization of nanofilled compared to universal and microfilled composites. Dent Mater 2007; 23: 51-59