Date of Award
Spring 1992
Document Type
Thesis - Restricted
Degree Name
Master of Science (MS)
Department
Dentistry
First Advisor
Dhuru, Virendra B.
Second Advisor
Ferguson, Donald J.
Third Advisor
Kittleson, Russell T.
Abstract
Current conventional visible light sources emit multi-chromatic, incoherent light of varying intensity. Because laser light is monochromatic, collimated and coherent, It would seem to be an ideal light source for activation of visible light activated composite resins. In June of 1991, Oralase laser systems, Salt Lake City, Utah, received FDA approval to market its Spectrum argon laser for curing of restorative composite dental resins. This experiment was designed to evaluate the effect of argon laser light vs. conventional visible light on the activation of composite resin during orthodontic bracket bonding procedures. Ninety bovine incisors were assigned to one of nine treatment groups. All teeth were prepared for bonding in the same manner. After applying orthodontic resin adhesive to the bracket bases, the brackets were placed on the enamel surface and exposed to one of two light sources. One of the nine treatment groups was exposed to a conventional visible light curing unit, exposure parameters were according to the adhesive manufacturer's recommendations. Eight of the groups were exposed to argon laser light. Exposure time, power, and site were varied for each of the eight laser groups. After bonding, the teeth were stored in room temperature distilled water for fourteen days prior to testing. A custom fabricated alignment apparatus and an lnstron machine were utilized to apply a tensile force. The force required to induce bond failure was recorded and the site of bond failure evaluated under a stereo microscope. On the basis of the results of this study, the following conclusions can be made: 1. Failure of the bond occurred at the bracket-adhesive interface in all cases. The enamel-adhesive bond was Intact. 2. There was no significant difference between tensile bond failure load values for the laser cured samples and the conventional light cured samples. 3. There was a significant difference between mean tensile bond failure loads among laser groups due to alterations in laser exposure power, site and duration. 4. Altering the exposure time did not significantly affect the laser treated groups when the laser settings were held constant. 5. Bond failure loads comparable to those obtained after 30 seconds exposure to conventional light curing units were obtained after only 4 seconds of laser exposure. In general, at one watt of power, the argon laser will take 87% less time than conventional visible light units to obtain similar bond failure loads. The benefit of the savings in clinical chairside time for laser light curing, as opposed to visible light curing, should be carefully weighed against the biohazards and the cost of laser light. Future research in this area should address the depth of cure obtained with visible light and laser light in the particular context of orthodontic bracket bonding procedures.
Recommended Citation
Sedivy, Mary Louise, "Tensile Bond Strength of Resin Adhesive Polymerized With An Argon Laser During Orthodontic Bracket Bonding Procedures" (1992). Master's Theses (1922-2009) Access restricted to Marquette Campus. 5384.
https://epublications.marquette.edu/theses/5384