A total of 30 rabbits were selected. The animals were divided into equal 6 groups, 5 animals each. While a control group received no treatment (G1: normal), the animals of experimental groups (G2 to G6) were anesthetized and the labial gingivae of the upper and lower anterior teeth were painted with a layer of a mixture of a 35% hydrogen peroxide solution and a bleaching agent during the application enamel bleaching utilizing a plasma arc lamp for three intervals, 20 minutes each. The animals were sacrificed after five intervals: (24 hours: G2, one week: G3, two weeks: G4, one month: G5 and two months: G6) subsequently. After each period of investigation, the gingiva of the rabbits were carefully dissected and prepared for transmission electron microscopy examination. The results revealed that bleaching effects on gingival tissue elements were of various degrees cellular and nuclear affections. Moderate to severe cellular and nuclear injuries may be produced as an early response to the bleaching effect. Subsequently, tissue injuries were of various degrees involving the different gingival tissue elements.
[Mohamed G. Attia-Zouair, Heba A. Adawy and Mohamed M. Fekry Khedr. Ultrastructure of the Cellular Response of Rabbits' Gingivae to the Adverse Effects of Light Enhanced Bleaching. Life Sci J 2012;9(1):910-923]. (ISSN:1097-8135). http://www.lifesciencesite.com. 134