Effects of KTP Laser Bleaching on Traumatized Tooth Enamel

Background: Bleaching of traumatized discolored teeth is considered an important issue in esthetic dentistry. Various methods have been introduced for bleaching, some of which may have adverse effects on soft or hard tissues of the tooth. Objectives: The objective of the study was to evaluate the effects of KTP laser bleaching on enamel of traumatized teeth. Materials and Methods: A square of ۳۶ mm۲ was chosen on the labial surface of ۳۲ extracted teeth. The corners were drilled in order to indicate the location precisely. The shade of each sample was recorded and the teeth were divided into four groups, each with eight teeth: group A (Smartbleach with KTP laser for ۳۰ seconds), group B (Smartbleach with G-Light for ۵ minutes), group C (only Smartbleach for ۱۰ minutes) and group D (control group with no bleaching). After one session of bleaching, shade assessment was performed again. In another experiment on nine teeth, Smartbleach with KTP laser was used for ۱۵۰ seconds to ۱۵۰۰ seconds. The samples were critically processed and observed by using scanning electron microscope (SEM) to assess enamel damage. Data was statistically analyzed using Kruskal-Wallis test (confidence interval level were set at ۹۵%). Results: Smartbleach was highly effective when used with KTP laser (P = ۰.۰۴۱۹). Enamel damage was observed after frequent KTP bleaching and ۷۵۰ seconds of KTP bleaching was recognized as the limit by morphological evaluation via SEM, indicating a major difference between under and over ۷۵۰ seconds of bleaching. Conclusions: Application of KTP laser may increase the bleaching effect of Smartbleach, nevertheless it may cause some enamel damage.