Degree of conversion and hardness of an orthodontic resin cured with a light-emitting diode and a quartz-tungsten-halogen light.

The purpose of this study was to assess the influence of two light units, a quartz-tungsten-halogen (QTH) and a light-emitting diode (LED), on the hardness and degree of conversion of an orthodontic composite resin. Sixty specimen disks were prepared from Transbond XT composite resin (3M Unitek) and light cured for 10, 20, and 30 seconds with a QTH (Curing Light XL 3000, 3M Unitek) or a LED (Ortholux, 3M Unitek) light-curing unit for 5, 10, and 15 seconds. Composite resin polymerization was evaluated by Fourier-transform infrared (FTIR) spectrophotometry and Knoop hardness number (KHN). The results were statistically analysed using analysis of variance and Tukey's multiple comparisons test (alpha = 0.05). The highest KHN was obtained with the QTH at 30 (25.19 KHN) and 20 (24.01) seconds, which did not differ statistically, and in the LED 15 second (21.86) group. The QTH 10 second group (20.53) did not differ statistically from the QTH 20 second or the LED 5 (19.96) and 15, or 10 second (18.95) groups. According to FTIR, there was no statistical difference for the degree of conversion among the groups, QTH 10 (43.42 per cent), QTH 20 (46.12 per cent), QTH 30 (45.30 per cent), LED 10 (47.02 per cent), or LED 15 (47.24 per cent) seconds. The lowest degree of conversion was obtained for the LED 5 second group (38.97 per cent), which did not differ statistically from the QTH 10 second group. Light curing with the LED resulted in a reduction of 50 per cent in the time recommended for use of the QTH light with the composite resin, Transbond XT.

[1]  M. F. Sfondrini,et al.  Effect of light-tip distance on the shear bond strengths of composite resin. , 2005, The Angle orthodontist.

[2]  T. Eliades,et al.  Light-cured or chemically cured orthodontic adhesive resins? A selection based on the degree of cure, monomer leaching, and cytotoxicity. , 2005, American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics.

[3]  S. Kalayci,et al.  Effect of LED and halogen light curing on polymerization of resin-based composites. , 2005, Journal of oral rehabilitation.

[4]  F. Rueggeberg,et al.  Correlation of bottom-to-top surface microhardness and conversion ratios for a variety of resin composite compositions. , 2004, Operative dentistry.

[5]  R. Kerby,et al.  Hardness and degree of conversion of posterior packable composites. , 2004, Operative dentistry.

[6]  Olaf Althoff,et al.  Curing performance of a new-generation light-emitting diode dental curing unit. , 2004, Journal of the American Dental Association.

[7]  G. Vougiouklakis,et al.  Curing efficiency of various types of light-curing units. , 2004, European journal of oral sciences.

[8]  D. Watts,et al.  Performance of two blue light-emitting-diode dental light curing units with distance and irradiation-time. , 2004, Dental materials : official publication of the Academy of Dental Materials.

[9]  K. Jandt,et al.  Second generation LEDs for the polymerization of oral biomaterials. , 2004, Dental materials : official publication of the Academy of Dental Materials.

[10]  S. Bishara,et al.  Evaluation of a new curing light on the shear bond strength of orthodontic brackets. , 2009, The Angle orthodontist.

[11]  A. Peutzfeldt,et al.  Influence of specimen diameter on the relationship between subsurface depth and hardness of a light-cured resin composite. , 2003, European journal of oral sciences.

[12]  W. Dunn,et al.  Polymerization of orthodontic resin cement with light-emitting diode curing units. , 2002, American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics.

[13]  D. Charlton,et al.  Polymerization efficiency of LED curing lights. , 2002, Journal of esthetic and restorative dentistry : official publication of the American Academy of Esthetic Dentistry ... [et al.].

[14]  Xiuling Wang,et al.  Light-curing technology: past, present, and future. , 2002, Compendium of continuing education in dentistry.

[15]  E. Swift.  Ask the Experts.: LED CURING LIGHTS , 2002 .

[16]  E. Swift.  LED curing lights. , 2002, Journal of esthetic and restorative dentistry : official publication of the American Academy of Esthetic Dentistry ... [et al.].

[17]  D. Es.  Light-emitting diodes in composite resin photopolymerization. , 2001 .

[18]  V. Bagnato,et al.  Hardness evaluation of a dental composite polymerized with experimental LED-based devices. , 2001, Dental materials : official publication of the Academy of Dental Materials.

[19]  J Sutalo,et al.  Degree of conversion and temperature rise during polymerization of composite resin samples with blue diodes. , 2001, Journal of oral rehabilitation.

[20]  S. Aj,et al.  Visible light-curing: part II. , 2001 .

[21]  E. Duke.  Light-emitting diodes in composite resin photopolymerization. , 2001, Compendium of continuing education in dentistry.

[22]  J. Nicholls.  Polymerization lights--light energy and wavelength. , 2000, Quintessence international.

[23]  K. Jandt,et al.  Restorative Dentistry: Dental composite depth of cure with halogen and blue light emitting diode technology , 1999, British Dental Journal.

[24]  M. Miyazaki,et al.  Evaluation of curing units used in private dental offices. , 1998, Operative dentistry.

[25]  P. Koran,et al.  Effect of sequential versus continuous irradiation of a light-cured resin composite on shrinkage, viscosity, adhesion, and degree of polymerization. , 1998, American journal of dentistry.

[26]  Nel Jc,et al.  Surface hardness of light-cured composite resin cured directly or through a transparent matrix using three different light guides. , 1996 .

[27]  T. Eliades,et al.  Polymerization efficiency of chemically cured and visible light-cured orthodontic adhesives: degree of cure. , 1995, American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics.

[28]  F. Rueggeberg,et al.  Calibration of FTIR conversion analysis of contemporary dental resin composites. , 1990, Dental materials : official publication of the Academy of Dental Materials.