Whitening Efficiency of Laser 940 nm and LED (450-505) nm on Extrinsic Stained Teeth (in vitro study)

Abstract

Background: Teeth staining is one of the esthetic problems faced by dentists and patients. Many methods
have been suggested as crowns, restorations and bleaching. Dental bleaching effectiveness depends on many
factors including technique and materials.
Objectives: Studying the effect of diode laser 940 nm and light emitting diode (450-505) nm in bleaching of
stained teeth regarding : whitening efficiency; pulp temperature; surface roughness and topography.
Materials and Methods: 40 extracted anterior teeth divided into 6 groups immersed at 37 oC in either
tea; coffee; cola ; juice for 14 days, tobacco stained teeth as well as control group were also included (
immersed in distilled water ). These groups were subdivided into laser group or light emitting diode group
bleached according to manufacturer specifications. Shades of teeth were recorded before and after bleaching.
Furthermore, temperature changes during bleaching were recorded using thermocouple Thermometer. All
specimens were examined under light microscope, Atomic Force Microscope and Sectioning Electronic
Microscope to study the surface roughness and topography.
Results: the light emitting diode group yielded slight significant whitening efficiency with more pulp
temperature rise (3.4 ºC) compared to the laser group (1.4 ºC). Both groups showed non-significant effect on
roughness and topography compared to control group.
Conclusion: Although light emitting diode group showed slightly significant shade improvement, but the
increase in pulp temperature was greater than that of laser group indicated better prognosis and safety when
diode laser 940 nm used. Conducting between efficiency and preservation, diode laser is superior in safety
and slightly similar whitening efficiency.