Abstract
This study was done to determine if there is any difference in microleakage between experimental composite resins, in which various proportions of three component photoinitiators (Camphoroquinone, OPPI, Amine) were included.
Four kinds of experimental composite resin were made by mixing 3.2% silanated barium glass (78 wt.%, average size; 1 µm) with each monomer system including variously proportioned photoinitiator systems used for photoinitiating BisGMA/BisEMA/TEGDMA monomer blend (37.5:37.5:25 wt.%). The weight percentage of each component were as follows (in sequence Camphoroquinone, OPPI, Amine): Group A - 0.5%, 0%, 1% / Group B - 2%, 0.2%, 2% / Group C - 0.2%, 1%, 0.2% / Group D - 1%, 1%, 2%.
Each composite resin was used as a filling material for round class V cavities (diameter: 2/3 of mesiodistal width; depth: 1.5 mm) made on extracted human premolars and they were polymerized using curing light unit (XL 2500, 3M ESPE) for 40 s with an intensity of 600 mW/cm2. Teeth were thermocycled five-hundred times between 50℃ and 550℃ for 30s at each temperature.
Electrical conductivity (µA) was recorded two times (just after thermocycling and after three-month storage in saline solution) by electrochemical method.
Microleakage scores of each group according to evaluation time were as follows [Group: at first record / at second record; unit (µA)]: A: 3.80 (0.69) / 13.22 (4.48), B: 3.42 (1.33) / 18.84 (5.53), C: 4.18 (2.55) / 28.08 (7.75), D: 4.12 (1.86) / 7.41 (3.41).
Just after thermocycling, there was no difference in microleakage between groups, however, group C showed the largest score after three-month storage. Although there seems to be no difference in microleakage between groups just after thermocycling, composite resin with highly concentrated initiation system or classical design (Camphoroquinone and Amine system) would be more desirable for minimizing microleakage after three-month storage.
References
1. Stansbury JW. Curing dental resins and composites by photopolymerization. J Esthet Dent. 2000. 12:300–308.
2. 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(1):121–131.
3. Ferracane JL, Mitchem JC, Condon JR, Todd R. Wear and marginal breakdown of composites with various degrees of cure. J Dent Res. 1997. 76:1508–1516.
4. Wataha JC, Hanks CT, Strawn SE, Fat JC. Cytotoxicity of components of resins and other dental restorative materials. J Oral Rehabil. 1994. 21:453–462.
5. Imazato S, Tarumi H, Kobayashi K, Hiraguri H, Oda K, Tsuchitani Y. Relationship between the degree of conversion and internal discoloration of light-activated composite. Dent Mater J. 1995. 14:23–30.
6. Rueggeberg FA, Ergle JW, Lockwood PE. Effect of photinitiator level on properties of a light-cured and post-cured heated model resin system. Dent Mater. 1997. 13:360–364.
7. Peutzfeldt A, Asmussen E. Influence of ketones on selected mechanical properties. J Dent Res. 1992. 71:1847–1850.
8. Peutzfeldt A, Asmussen E. In vitro wear, hardness, and conversion of diacetyl-containing resin materials. Dent Mater. 1996. 12:103–108.
9. Rietschel RL. Contact allergens in ultraviolet-cured acrylic resin systems. Occup Med. 1986. 1:301–306.
10. Cohen SG, Chao HM. Photoreduction of aromatic ketones by amine. Studies of quantum yields and mechanism. J Am Chem Soc. 1968. 90:165–173.
11. Antonucci JM, Venz S. Tertiary amine salts and complexes as chemical and photochemical accelerators. J Dent Res. 1987. 66:128–Abstr. No. 170.
12. Puppala R, Hegde A, Munshi AK. Laser and light cured composite resin restoration : in-vitro comparison of isotope and dye penetration. J Clin Pediatric Dent. 1996. 20:213–218.
13. Park YJ, Chae KH, Rawls HR. Development of a new photoinitiation system for dental light-cure composite resin. Dent Mater. 1999. 15:120–127.
14. Inano H, Ohba H, Tamaoki B. Photochemical inactivation of human placental estradiol 17 beta-hydrogenase in the presence of 2,3-butandion. J Steroid Biochem. 1983. 19:1617–1622.
15. Eick JD, Kostoryz EL, Rozzi SM, Jacobs DW, Oxman JD, Chappelow CC, Glaros AG, Yourtee DM. In vitro biocompatibility of oxirane/polyol dental composites with promising physical properties. Dent Mater. 2002. 18:413–421.
16. Labella R, Lambrechts P, Van Meerbeek B, Vanherle G. Polymerization shrinkage and elasticity of flowable composites and filled adhesives. Dent Mater. 1999. 15:128–137.
17. Davidson CL, Feilzer AJ. Polymerization shrinkage and polymerization shrinkage stress in polymer-based restoratives. J Dent. 1997. 25:435–440.
18. Braga RR, Ferracane JL. Contraction stress related to degree of conversion and reaction kinetics. J Dent Res. 2002. 81(2):114–118.
19. Ferracane JL, Mitchem JC. Relationship between composite contraction stress and leakage in Class V cavities. Am J Dent. 2003. 16(4):239–243.
20. Gale MS, Darvell BW, Cheung GS. Three-dimensional reconstruction of microleakage pattern using a sequential grinding technique. J Dent. 1994. 22(6):370–375.
21. Crim GA, Chapman KW. Reducing microleakage in Class V restorations: an in vitro study. Quint Int. 1994. 25(11):781–785.
22. Shin DH, Rawls HR. Degree of conversion and color stability of the light curing resin with new photoinitiator systems. Dent Mater. 2009. (in press).
23. Koo BJ, Shin DH. The effect of c-factor and volume on microleakage of composite resin restorations with enamel margins. J Korean Acad Conserv Dent. 2006. 31(6):452–459.
24. Brannstrom M. Communication between the oral cavity and the dental pulp associated with restorative treatment. Oper Dent. 1984. 9:57–68.
25. Tantbirojn D, Versluis A, Pintado MR, DeLong R, Douglas WH. Tooth deformation patterns in molars after composite restoration. Dent Mater. 2004. 20:535–542.
26. Park JW. Comparison of the residual stress of the nanofilled composites. J Korean Acad Conserv Dent. 2008. 33(5):457–462.
27. Gladys S, Meerbeer VB, Lambrechts P, Vanherle G. Microleakage of adhesive restorative materials. Am J Dent. 2001. 14(3):170–176.
28. Hannig M, Friedrichs C. Comparative in vivo and in vitro investigation of interfacial bond variability. Oper Dent. 2001. 26(1):3–11.
29. Jacobsen PH, Von Fraunhofer JA. Assessment of microleakage using a conductimetric technique. J Dent Res. 1976. 54(1):41–48.
30. Delivanis PD, Chapman KA. Comparison and reliability of techniques for measuring leakage and marginal penetration. Oral Surg Oral Med Oral Pathol. 1982. 53:410–416.
31. Kim CY, Shin DH. Microleakage of composite resin restoration according to the number of thermocycling. J Korean Acad Conserv Dent. 2007. 32(4):377–384.
32. Mattison GD, Von Fraunhofer JA. Electrochemical microleakage study of endodontic sealer/cements. Oral Surg Oral Med Oral Pathol. 1983. 55:402–407.
33. Iwami Y, Yamamoto H, Ebisu S. A new electrical method for detecting marginal leakage of in vitro resin restorations. J Dent. 2000. 28:241–247.
34. Nakano Y. A new electrical testing method on marginal leakage of composite resin restorations. Jpn J Cons Dent. 1985. 8:1183–1198.