Baena MT, Guerrero IJ, Álvarez GC, Celis RL

Language: Spanish
References: 14
Page: 237-241
PDF size: 155.25 Kb.

ABSTRACT

Dual resin based cements used for indirect aesthetic restorations sustain shrinkage due to polymerization, which can increase as the ceramic restoration thickness increases. This shrinkage generates contraction efforts which induce problems in the inner phase located between the tooth and restoration. The objective of this study was to determine the influence exerted by the thickness of the ceramic restoration in the polymerization shrinkage of three dual luting cements. 1, 1.5 and 2 mm thick IPS Empress^® ceramic disks were manufactured . Polymerization shrinkage of cements Variolink II (Ivoclar, Vivadent, Liechtenstein), Maxcem (Kerr, Orange, USA) and Duolink (Bisco, Schaumburg, USA) was assessed using the Watts and Cash method. For each cement, 10 control determinations were performed impacting the light without using a ceramic disk; 10 impacting the light through a 1 mm ceramic disk, 10 through a 1.5 ceramic disk and 10 through a 2 mm ceramic disk. Results were analyzed with ANOVA. Statistically significant differences were found among the three cements in the control group when compared to experimental cements. Variolink II was the cement exhibiting lesser shrinkage percentage in all groups. Thickness of restorations significantly influenced polymerization shrinkage. This fact must be well taken into account by the clinical operator when dealing with dental preparations.

REFERENCES

1. Braga RR, Ballester RY, Ferracane JL. Factors involved in the development of polymerization shrinkage stress in resin-composites: A systematic review. Dent Mater 2005; 21: 962-970.

2. Braga RR, Ferracane JL, Condon JR. Polymerization contraction stress in dual-cure cements and its effect on interfacial integrity of bonded inlays. J Dent 2002; 30: 333-340.

3. Alster D, Feilzer AJ, De Gee AJ, Mol A, Davidson CL. The dependence of shrinkage stress reduction on porosity concentration in thin resin layers. J Dent Res 1992; 71: 1619-22.

4. Atai M, Watts DC. A new kinetic model for the photopolymerization shrinkage-strain of dental composites and resin-monomers. Dent Mater 2006; 22: 785-791.

5. Aw TC, Nicholls JI. Polymerization shrinkage of densely-filled resin composites. Oper Dent 2001; 26: 498-504.

6. Dumfahrt H. Porcelain laminate veneers. A retrospective evaluation after 1 to 10 years of service: Part I. Clinical procedure. Int J Prosthodont 1999; 12: 505-13.

7. Labella R, Lambrechts P, Van Meerbeek B, Vanherle G. Polymerization shrinkage and elasticity of flowable composites and filled adhesives. Dent Mater 1999; 15: 128-37.

8. Cardash HS, Baharav H, Pilo R, Ben-Amar A. The effect of porcelain color on the hardness of luting composite resin cement. J Prosthet Dent 1993; 69: 620-3.

9. Uctasli S, Hasanreisoglu U, Wilson HJ. The attenuation of radiation by porcelain and its effect on polymerization of resin cements. J Oral Rehabil 1994; 21: 565-75.

10. El-Mowafy AM, Rubo MH, el-Badrawy WA. Hardening of new resin cements cured through a ceramic inlay. Oper Dent 1999; 24: 38-44.

11. Jung H, Friedl KH, Hiller KA, Furch H, Bernhart S, Schmalz G. Polymerization efficiency of different photocuring units through ceramic discs. Oper Dent 2006; 31: 68-77.

12. Rees JS, Jacobsen PH. Stresses generated by luting resins during cementation of composite and ceramic inlays. J Oral Rehabil 1992; 19: 115-122.

13. Watts DC, Marouf AS, Al-Hindi AM. Photo-polymerization shrinkage-stress kinetics in resin composites: methods development. Dent Mater 2003; 19: 1-11.

14. Watts DC, Cash AJ. Determination of polymerization shrinkage kinetics in visible-light-cured materials: methods development. Dent Mater 1991; 7: 281-287.