The dental pulp: inflammatory markers and vital bleaching.

PURPOSE: To evaluate the expression of specific neuropeptides associated with inflammation, substance-P (SP) and calcitonin gene-related peptide (CGRP), after night guard vital bleaching with 10% carbamide peroxide gel. METHODS: 10 patients with four caries free premolars scheduled for orthodontic extraction had these teeth bleached with 10% Opalescence as follows: tooth #28, no treatment (control); #5, 4 days of bleaching; #12, 2 weeks of bleaching; #21, 2 weeks of bleaching, followed by 2 weeks without treatment. All teeth in the four groups were extracted at the same time. Immediately after extraction the teeth were frozen at -197 degrees C in liquid nitrogen. The pulp samples were prepared for enzyme-linked immunoabsorbent assay (ELISA) to determine the concentrations of the SP, CGRP and total protein in the pulp tissue. RESULTS: The analysis of mean SP and mean CGRP/ng protein/ml resulted in no significant differences among the four groups. It was concluded that the study did not demonstrate an increase in the release of SP and/or CGRP during night guard vital bleaching of teeth with 10% Opalescence.

Pulp reaction to vital bleaching.

This study evaluated the histological changes in dental pulp after nightguard vital bleaching with 10% carbamide peroxide gel. Fifteen patients between 12 and 26 years of age with caries-free first premolars scheduled for orthodontic extraction were treated with 10% Opalescence (Ultradent Products, Inc). Tooth #5 had four days of bleaching, tooth #12 was treated for two weeks, tooth #21 was bleached for two weeks followed by two weeks without treatment and tooth #28, serving as the control, was without treatment. All teeth were extracted at the same time. Immediately after extraction, 4 mm of the most apical portion of the root was sectioned off and each specimen was placed in a vial containing 10% neutral buffered formalin. The samples were prepared for histological evaluation at the Scandinavian Institute of Dental Materials (NIOM) and microscopically examined independently at both NIOM and Indiana University School of Dentistry (IUSD). Pulp reactions were semi-quantitatively graded as none, slight, moderate and severe. Slight pulpal changes were detected in 16 of the 45 bleached teeth. Neither moderate nor severe reactions were observed. The findings indicate that the slight histological changes sometimes observed after bleaching tend to resolve within two weeks post-treatment. Statistical differences existed only between the untreated control and the four-day (p=0.0109) and two-week (p=0.0045) treatment groups. The findings from this study demonstrated that nightguard vital bleaching procedures using 10% carbamide peroxide might cause initial mild, localized pulp reactions. However, the minor histological changes observed did not affect the overall health of the pulp tissue and were reversible within two weeks post-treatment. Therefore, two weeks of treatment with 10% carbamide peroxide used for nightguard vital bleaching is considered safe for dental pulp.