Comparation of Hardness of Resin Composite Samples with Three Different Curing Methods with LED Curing and QTH Equipments

Document Type : Original Article

Authors

1 Department of Operative and Esthetic Dentistry, Faculty of Dentisty, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran

2 Department of Operative and Esthetic Dentistry, Faculty of Dentisty, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

Abstract

Background and Objectives: The use of composite material for posterior teeth due to the esthetic demands of patients is increasing. One of the major problems of composites is the polymerization rate. Inadequate polymerization due to improper curing will result in less hardness. As a solution the best light curing system can be considered. The aim of this study was to comparate the hardness of resin composite samples with three different curing methods with LED curing and QTH equipments.                                              
Materials and Methods: In this experimental study 100 sample composite (valux plus 3M, USA) was fabricated by stainless steel mold (thickness 2mm, diameter 6mm). The teeth were divided into 4 groups of 25 (one control and 3 experimental groups). Each of the experimental group was exposed to one of the curing protocols of LED (conventional, stepped, ramped) for 20s and control group for 20 s was cured by QTH. The samples were stored at room temperature in the dark for 24 hr, then Vickers micro hardness testing was performe on the upper and lower surfaces of all samples.
Results: Significant differences were demonstrated between the different LCUs in lower and upper surfaces (P<0.05). No significant differences in the hardness between the lower and upper surfaces was found in the LED-treated groups (P>0.05).
Conclusion: Between the two sets of LED and QTH, the role of LED curing in all modes is superiorly effective in promting more hardness.
 

Keywords


1-Zhengdi He, Yasushi shimada, Junji Tagami. The effects of cavity size and incremental technique on micro–tensile bond strength of resin composite in class I cavities. J Oper  Dent  2007 May; 23(5): 533-538.
2-Craig G, Robert M. Dental material restorative. 11th ed. USA: Mosby; 2006. P. 187-144.
3-Bala O, Uctasli M, Tuz M. Barcol hardness of different resin-based composites cured by halogen or light emitting diod. J Oper  Dent 2005; 30(1): 69-74.
4-Asmussen E, Peutz A. Light emitting diode curing: influence on selected properties Resin composite. Quintessence Int J Oper  Dent 2003; 34(1): 5-7.
5-Dunn W, Bush A. A comparison of polymerization by light-emitting diode and halogen-based light units. J Am DentAssoc 2002; 133(3): 335-41.
6-Oxman J, Paton B, Felix C. Effect of wave length on resin hardness & light transmission. 8th ed. USA: Mosby; 2004. P. 117.
7-Ramp L, Broome J, Ramp M. Hardness and wear resistance of two resin composites cured with equivalent radiant exposure from a low irradiance LED and QTH light-curing units. Am J Dent 2006; 19(1): 6-9.
8-Yazici A, Kugel G, Gul G. The Knoop hardness of a composite resin polymerized with different curing lights and different modes. J Contemp Dent Pract 2007; 8(2): 52-9.
9- Toroghi A. Evaluation of Light Cure Unit on Micro Hardness of Composite Z250. Dissertation. Azad Eslami Tehran University of Medical Sciences 1386, Iran; 2007.
10-Roberson TM , Heymann HO, Swift EJ . Sturdevant's Art and science   of operative dentistry .5th ed. USA: Mosby; 2006.
11-Hassani tabatabaie M, Ataie M. Effect of different curing methods and microleakage and degree of conversion of composite resin restorations. J Dent TUMS 2003;16(2): 18-27.
12-Dunn WJ, Bush AC. A comparison of polymerization by light- emitting diode and halogen-base light-curing units. J Am Dent Assoc 2002; 133(3): 335-41.
13-Oberholzer TG , Kidd M . Effect of LED curing on microleakage and microhardness of class v resin-base composite restorations. J Oper  Dent 2004; 54(1): 15-20.
14-Paul C.L, Laurence J. Depth of cure and surface microhardness of composite resin cured with blue LED curing lights. J Dent Mat  2004; 20: 364-369.
15-Theunis G , Oberholzer. Effect of LED curing on the microleakage , shear bond strength and surface hardness of a resin – based composite restoration. J Dent Mat 2005; 26: 3981-3986.
16-Richard BT, Corey AF. Knoop hardness of ten resin composite irradiation with high – power LED and quarts-tungsten – halogen light, J Oper  Dent 2005; 26: 2631-2641.
17-Cecllia MC. knoop hardness of composite cured wih halogen and led light-curing units in class 1 restorations. Braz J Oral Sci 2009; 30-33
18-Alaghehmand H , Safarcherati H , Ghasemzadeh Azar F. Evaluation of hardness of dental composites polymerized by halogen or LED light curing units. J of Ghasr-e-Baran2009;1(1)
19-Hassan  A, Hassab A . Evaluation of the microleakage , curing depth and micrhardness of composite resins using a Halogen and LED . J Dent 2009; 55(4,2): 2555.
20-Yap A, Seneviratre C. Influence of light energy density on egffectiveness of composite cure. Oper Dent 2001; 26: 460-66.
21-Summit JB, Robbins Jw, Schwartz Rs. Fundamentals of operative dentistry. 2nd ed. philadelphia: Quitessence; 2006.
22-Lopes LG, Franco EB, Neto AN, Herrea FS. Polymerization of dual cured cements throught ceramic: LED curing light vs halogen lamp. J Appl oral sci 2004 sep;12(4):312-316.
23-Yap A , Sob M .Curing efficacy of a new generation high power LED lamp . Oper Dent 2005; 30(6): 728-763.
24-Claus-peter E, Gerrit R. Depth of cure of LED VS QTH Light-curing Devices at a distance of 7mm.J Adhesive Dentistry 2004; 15(6): 141-50.
25-Anders L, Anne P. Effect of power density of curing unit, exposure duration, and light guide distance on composite depth of cure cline oral invests. Quintessence Int 2005; 12(9): 71-6.
 26-Consanis H, Ogliari F, Correr A. Effect of time and polymerization cycle on the degree of conversion of a resin composite. J Oper Dent 2006; 31(4): 489-99.
27-Poor Ahmadi M. Evaluation of light cure distance on micro hardness of 2 type of flowable composit. Dissertation. Azad Eslami Tehran University of Medical Sciences, Iran;Azad Eslami Tehran University Of Medical Sciences;1385-5.  
28-Bala O, Uctasli M, Tuz M. Barcol hardness of different resin-based composites cured by halogen or light emitting diod. J Oprative Dentistry 2005; 30(1): 69-74.
29-Price RB , Felix CA , Andreou P . Knoop hardness of ten resin composites irradiated with high power LED and quartz-tungsten-halogen lights.Biomater 2005; 26(15): 2631-2641.
30-Felix C , Price R , Andreou P . Curing depths of QTH and LED curing lights . J Dent Res 2004 ; 83: 82-86.
31-Santos GB , Medeiros IS , Braga RR. Composite depth of cure obtained with QTH and LED units assessed by microhardness and micto-Raman spectroscopy. Oper D ent 2007; 32 (1): 79 -83.
32-Soh MS , Yap A , Siow k . Effectivness of composite cure associated with different curing modes of LED lights . Oper Dent 2003; 28(4): 337-71.
33-Abate P , Zahra V .Effect of polymerization variable on composite hardness. J Prosth Dent 2001; 86(6): 632-5.