Purpose: To assess the accuracy and efficiency of UV illumination compared to conventional white light in the detection of adhesive during orthodontic debonding.

Materials and Methods: A pilot investigation was first done to evaluate different orthodontic adhesives for inclusion in the main study. An in-vitro study was then conducted using 80 human extracted premolars divided into 4 groups (N = 20) according to the brand of adhesive and type of light used during adhesive removal. Groups were designated P-W, P-UV, O-W, and O-UV according to their adhesive-light combination (Pad Lock = P, Opal Bond MV = O, white light = W, UV light = UV). Adhesive removal was performed with teeth mounted to a mannequin head to simulate clinical interaction. White light from the dental chair or a UV LED flashlight was used during removal depending on the assigned group. Time (seconds) was recorded for the cleanup of each tooth. Images were then taken of the teeth with UV light and surface area of adhesive remnants (mm2) were calculated using Image J software. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) were used to assess the sensitivity of UV light in adhesive detection. Analysis of variance (ANOVA) and Kruskal-Wallis tests were used to analyze time and adhesive remnants among groups, respectively. Corresponding post hoc tests followed.

Results: Groups with UV light had statistically significantly lower amounts of adhesive remnants than groups with white light (O-UV vs. P-W, p ≤ 0.001; O-UV vs. O-W, p ≤ 0.001; P-UV vs. P-W, p = 0.003, P-UV vs. O-W, p ≤ 0.001). Groups with UV light were also found to be statistically significantly lower in mean time than O-W (O-W vs. O-UV, p ≤ 0.001; O-W vs. P-UV, p = 0.005). SEM backscatter electron (BSE) images confirmed presence of adhesive in locations that fluoresced on UV images, but areas with adhesive thickness < 2 microm were not detected by UV light.

Conclusion: UV light is more accurate and may be more efficient than white light in the detection of fluorescent adhesive during orthodontic debonding. While there are limitations, a UV LED flashlight is a practical tool that provides certainty in adhesive detection and minimal adhesive remnants.