Effect of heat treatment on cytotoxicity of self-adhesive resin cements: Cell viability analysis

ABSTRACT

Objective: The aim of the study was to assess, in vitro, the influence on cytotoxicity of heat treatment applied before photopolymerization, while mixing three self-adhesive resin cements, in an NIH/3T3 fibroblast cell culture, based on cell viability measures. Methods: Samples were divided into three groups: (1) no heat treatment while mixing (control), (2) 37°C, and (3) 60°C heat treatment while mixing. Cements were light-cured immediately after mixing and immersed in Dulbecco's Modified Eagle Media for the extraction of possibly uncured products after 24 h and 7 days. Cultures contained 0.5 mL of NIH/3T3 fibroblasts per well at a concentration of 0.4 × 10⁵ cells/mL and specific extracts for each sample. Statistical Analysis Used: Data were statistically analyzed with ANOVA and post hoc Student–Newman–Keuls (significance of 5%). Results: Cement cytotoxicity increased with time, as shown by the higher values observed at 7 days. There was a slight difference in intragroup cytotoxicity levels between 24 h and 7 days. Heat treatment at 60°C was associated with a major decrease in cytotoxicity levels in all three groups, both at 24 h and at 7 days, with no differences among the cements. Conclusions: Heat treatment at 60°C should be considered as a strategy to reduce cytotoxicity of self-adhesive resin cements, as evidenced by the results observed at 24 h and 7 days of analysis.

Key words:

Biocompatibility - dental materials - toxic substances

• REFERENCES

• 1 Lee IB, Um CM. Thermal analysis on the cure speed of dual cured resin cements under porcelain inlays. J Oral Rehabil 2001; 28: 186-97
• 2 Anchieta RB, Rocha EP, de Almeida EO, Junior AC, Martini AP. Bonding all-ceramic restorations with two resins cement techniques: A clinical report of three-year follow-up. Eur J Dent 2011; 5: 478-85
• 3 Burke FJ, Watts DC. Fracture resistance of teeth restored with dentin-bonded crowns. Quintessence Int 1994; 25: 335-40
• 4 Hikita K, Van Meerbeek B, De Munck J, Ikeda T, Van Landuyt K, Maida T. et al. Bonding effectiveness of adhesive luting agents to enamel and dentin. Dent Mater 2007; 23: 71-80
• 5 De Munck J, Vargas M, Van Landuyt K, Hikita K, Lambrechts P, Van Meerbeek B. et al. Bonding of an auto-adhesive luting material to enamel and dentin. Dent Mater 2004; 20: 963-71
• 6 Abo-Hamar SE, Hiller KA, Jung H, Federlin M, Friedl KH, Schmalz G. et al. Bond strength of a new universal self-adhesive resin luting cement to dentin and enamel. Clin Oral Investig 2005; 9: 161-7
• 7 Hitz T, Stawarczyk B, Fischer J, Hämmerle CH, Sailer I. Are self-adhesive resin cements a valid alternative to conventional resin cements? A laboratory study of the long-term bond strength. Dent Mater 2012; 28: 1183-90
• 8 Ergun G, Egilmez F, Yilmaz S. Effect of reduced exposure times on the cytotoxicity of resin luting cements cured by high-power led. J Appl Oral Sci 2011; 19: 286-92
• 9 Ilie N, Hickel R. Correlation between ceramics translucency and polymerization efficiency through ceramics. Dent Mater 2008; 24: 908-14
• 10 Archegas LR, de Menezes Caldas DB, Rached RN, Soares P, Souza EM. Effect of ceramic veneer opacity and exposure time on the polymerization efficiency of resin cements. Oper Dent 2012; 37: 281-9
• 11 Borges GA, Agarwal P, Miranzi BA, Platt JA, Valentino TA, dos Santos PH. et al. Influence of different ceramics on resin cement knoop hardness number. Oper Dent 2008; 33: 622-8
• 12 Kilinc E, Antonson SA, Hardigan PC, Kesercioglu A. The effect of ceramic restoration shade and thickness on the polymerization of light- and dual-cure resin cements. Oper Dent 2011; 36: 661-9
• 13 Silikas N, Eliades G, Watts DC. Light intensity effects on resin-composite degree of conversion and shrinkage strain. Dent Mater 2000; 16: 292-6
• 14 Flury S, Lussi A, Hickel R, Ilie N. Light curing through glass ceramics with a second- and a third-generation LED curing unit: Effect of curing mode on the degree of conversion of dual-curing resin cements. Clin Oral Investig 2013; 17: 2127-37
• 15 Watanabe H, Kazama R, Asai T, Kanaya F, Ishizaki H, Fukushima M. et al. Efficiency of dual-cured resin cement polymerization induced by high-intensity LED curing units through ceramic material. Oper Dent 2015; 40: 153-62
• 16 Pereira AG, Raposo L, Teixeira D, Gonzaga R, Cardoso IO, Soares CJ. et al. Influence of battery level of a cordless LED unit on the properties of a nanofilled composite resin. Oper Dent 2016; 41: 409-16
• 17 Moszner N, Salz U, Zimmermann J. Chemical aspects of self-etching enamel-dentin adhesives: A systematic review. Dent Mater 2005; 21: 895-910
• 18 Obici AC, Sinhoreti MA, de Goes MF, Consani S, Sobrinho LC. Effect of the photo-activation method on polymerization shrinkage of restorative composites. Oper Dent 2002; 27: 192-8
• 19 International Organization for Standardization. ISO 1099312: Biological Evaluation of Medical Devices. Part 12: Sample Preparation and Reference Materials Geneva: International Organization for Standardization; 2002
• 20 Price RB, Felix CA, Andreou P. Evaluation of a second-generation LED curing light. J Can Dent Assoc 2003; 69: 666
• 21 Dolez P, Marek M, Love BJ. Photopolymerizable acrylic resin: Effect of curing time and temperature. J Appl Polym Sci 2001; 82: 546-54
• 22 Trujillo M, Newman SM, Stansbury JW. Use of near-IR to monitor the influence of external heating on dental composite photopolymerization. Dent Mater 2004; 20: 766-77
• 23 Ferracane JL, Condon JR. Post-cure heat treatments for composites: Properties and fractography. Dent Mater 1992; 8: 290-5
• 24 Reinhardt JW, Boyer DB, Stephens NH. Effects of secondary curing on indirect posterior composite resins. Oper Dent 1994; 19: 217-20
• 25 Klein-Júnior CA, Zander-Grande C, Amaral R, Stanislawczuk R, Garcia EJ, Baumhardt-Neto R. et al. Evaporating solvents with a warm air-stream: Effects on adhesive layer properties and resin-dentin bond strengths. J Dent 2008; 36: 618-25
• 26 Souza RO, Ozcan M, Michida SM, de Melo RM, Pavanelli CA, Bottino MA. et al. Conversion degree of indirect resin composites and effect of thermocycling on their physical properties. J Prosthodont 2010; 19: 218-25
• 27 Stanley HR. Biological evaluation of dental materials. Int Dent J 1992; 42: 37-46
• 28 Goldberg M. In vitro and in vivo studies on the toxicity of dental resin components: A review. Clin Oral Investig 2008; 12: 1-8
• 29 Bakopoulou A, Mourelatos D, Tsiftsoglou AS, Giassin NP, Mioglou E, Garefis P. et al. Genotoxic and cytotoxic effects of different types of dental cement on normal cultured human lymphocytes. Mutat Res 2009; 672: 103-12
• 30 al-Fawaz A, Gerzina TM, Hume WR. Movement of resin cement components through acid-treated dentin during crown cementation in vitro . J Endod 1993; 19: 219-23
• 31 Retamoso LB, Luz TB, Marinowic DR, Machado DC, De Menezes LM, Freitas MP. et al. Cytotoxicity of esthetic, metallic, and nickel-free orthodontic brackets: Cellular behavior and viability. Am J Orthod Dentofacial Orthop 2012; 142: 70-4
• 32 Almaroof A, Niazi SA, Rojo L, Mannocci F, Deb S. Evaluation of dental adhesive systems incorporating an antibacterial monomer eugenyl methacrylate (EgMA) for endodontic restorations. Dent Mater 2017; 33: e239-54
• 33 Catunda RQ, Vieira JR, de Oliveira EB, da Silva EC, Brasil VL, Perez DC. et al. Citotoxicity evaluation of three dental adhesives on vero cells in vitro . J Clin Exp Dent 2017; 9: e61-e66
• 34 Rizzo M, Evangelista M, Mariani L, Simili M, Rainaldi G, Pitto L. et al. Immortalized mouse embryo fibroblasts are resistant to miR-290-induced senescence regardless of p53 status. Physiol Genomics 2011; 43: 1153-9
• 35 Dioguardi M, Perrone D, Troiano G, Laino L, Ardito F, Lauritano F. et al. Cytotoxicity evaluation of five different dual-cured resin cements used for fiber posts cementation. Int J Clin Exp Med 2015; 8: 9327-33
• 36 Bausch JR, de Lange C, Davidson CL. The influence of temperature on some physical properties of dental composites. J Oral Rehabil 1981; 8: 309-17
• 37 Lovell LG, Lu H, Elliott JE, Stansbury JW, Bowman CN. The effect of cure rate on the mechanical properties of dental resins. Dent Mater 2001; 17: 504-11
• 38 Reis A, Klein-Júnior CA, de Souza FH, Stanislawczuk R, Loguercio AD. The use of warm air stream for solvent evaporation: Effects on the durability of resin-dentin bonds. Oper Dent 2010; 35: 29-36
• 39 Moura SK, Murad CG, Reis A, Klein-Júnior CA, Grande RH, Loguercio AD. et al. The influence of air temperature for solvent evaporation on bonding of self-etch adhesives to dentin. Eur J Dent 2014; 8: 205-10
• 40 Moraes RR, Faria-e-Silva AL, Ogliari FA, Correr-Sobrinho L, Demarco FF, Piva E. et al. Impact of immediate and delayed light activation on self-polymerization of dual-cured dental resin luting agents. Acta Biomater 2009; 5: 2095-100