Ultraviolet LED Illumination as an Aid for Composite Resin Removal

Composite resin restorations whose shades are well matched to that of teeth and are contoured to be anatomically correct may be difficult to recognize by visual inspection. A technique utilizing ultraviolet (UV) LED light to cause restorative resins to fluoresce is introduced as aid in composite resin detection and removal.

Methods:

In vitro testing was performed to evaluate efficacy of three wavelengths (365, 385, 395nm) of UV LED lights and fluorescence response of enamel, dentin and composite resins. Fluorescence spectroscopy was performed with a UV-Visible light spectrophotometer. The fluorescence intensity and emission maxima of 24 composite resin brands were measured in order to anticipate the visible contrast of restorations relative to tooth structure. Control samples of dentin and enamel were similarly measured. Subsequently, each brand of resin was placed in extracted teeth and the relative fluorescence assessed. The resins were removed and each tooth was inspected utilizing UV light to detect any remaining resin.

Results:

It was determined that 385nm was the best excitation wavelength for resin detection. The resins were grouped based on relative fluorescence to enamel and dentin. Three groups emerged: those which fluoresced brighter than, less than and the same as dentin and enamel. The lights revealed resin remaining in the extracted teeth, in each circumstance, when it was assumed all had been removed.

Conclusions:

The LED light was a very effective tool in revealing the existence of composite resins when the resin fluoresced brighter than enamel and dentin. The use of ultraviolet illumination proved to be a useful means of determining if an existing composite had been completely removed.