Aim: With the introduction of photosensitive (light-cured) restorative materials in dentistry, various methods were suggested to enhance their polymerization and shorten the curing time, including layering and the use of more powerful light-curing devices. The purpose of this study was to determine the effect of using two light guides with different recommended curing times on the shear bond strength of an orthodontic adhesive, within 30 minutes after bonding. Material and Methods: The light-curing apparatus was the Hilux 250, which has a number of accessories. The two light guides were the 11-mm-diameter Standard Curved Light Guide and the 8-mm-diameter Curved Turbo Accelerator Light Guide. The bonding adhesive system was Ideal. The teeth were randomly divided into two groups according to the light guide tip and the recommended exposure time. The curing time with the standard light guide was 40 seconds, while it was 10 seconds with the Turbo light guide. Results: The findings indicated that when the teeth were debonded within 30 minutes after light curing, the Standard light guide used for 40 seconds (mean = 5.6 ± 3.6 MPa) produced significantly stronger shear bond strength than the Turbo light guide used for 10 seconds (mean = 2.7 ± 2.2 MPa). There were no significant differences in the bracket/adhesive/ enamel failure sites. Conclusion: When bonding orthodontic metal brackets, the Turbo light guide with the reduced light-cure time provided significantly lower bond strength when compared to the Standard light guide in the first 30 minutes after bonding, when the initial archwires are tied into place. World J Orthod 2001;2:154-158.