Methods: 40 volunteers aged 18 years and older (27.3) having all natural healthy teeth in shade A3 or darker on the Vita Shade Guide were randomly assigned to four groups (n=10). Group 1: received bleaching without light activation (Opalescence Xtra Boost, Ultradent); Group 2: with diode laser (Laser Smile /Biolase); Group 3: with plasma arc light (Remecure CL15 / Remedent); Group 4: with LED light (By White /Ensodent) according to the manufacturers' recommendations. Shade assessments were made using Classical Vita Shade Guide (Vita Zahnfabrik, H.Rauter GmbH) and a digital spectrophotometer (Vita Easy Shade, Vident) at baseline and after treatments. Any side effect on teeth or gingiva was recorded by Visual Analog Scale (VAS). Results were analyzed using one way ANOVA, Kruskal-Wallis and Mann-Whitney U test with Bonferroni correction.
Results: All the techniques resulted in shade change with Vita Shade Guide but there were no significant differences among four groups (p>0.05).Spectrophotometer readings exhibited significant differences among the groups (p<0,05). The overall shade change values expressed as DL, Da, Db, DE for group 2 was significantly higher than the other groups (p<0,05). Laser assisted bleaching system showed lower VAS scores (p<0.05) than the other groups.
Conclusions: Whether they are used with or without light, in-office bleaching techniques lead to an expected shade change. Although the use of shade guide didn't exhibit any differences among the groups, spectrophotometer readings showed different findings. As laser assisted bleaching resulted in less sensitivity and higher color change; it could be preferred among the other in–office bleaching systems.