Purpose: A novel overnight bleaching system containing 19% sodium percarbonate and silicone film forming agents (Crest Night Effects) is described, along with research supporting the substantivity of the product on tooth surfaces and its resulting whitening efficacy.
Methods: Nine adult volunteers were enrolled in a study to determine overnight retention (substantivity) of the product. A non-reactive blue pigment was added to the product to aid in evaluating retention. The participants applied the product to their anterior dentition at night and then had digital images taken. After 7 hours of sleep, the patients were awakened and re-imaged. The percent coverage with blue pigment on the surfaces of the 12 anterior teeth was calculated from the digital images after application and after awakening. The product was also evaluated in a 2-week efficacy study with 16 adult volunteers. Each night the participants brushed their teeth before going to bed as they normally would, dried their teeth with a towel, and then applied the product to their six maxillary and mandibular anterior teeth. The product was left on the teeth overnight and then removed in the morning via toothbrushing. Color (baseline and after 2 weeks of product usage) was determined using digital imaging and the standard L*a*b* measurement scale.
Results: In the substantivity study, 84.7% of the subject teeth surfaces were covered on average with the blue pigment-containing film immediately after application. Following overnight use, excellent retention was demonstrated as 77.4% of the initially covered surfaces still had pigment-containing film on them. These means did not differ significantly (P > 0.44). In the clinical efficacy study, there was significant (P < 0.0001) color improvement versus baseline after 2 weeks of treatment as measured by a mean (SD) delta b* of -1.71 (0.85) and mean (SD) delta L* of 1.62 (0.68). The product was well-tolerated, with the primary adverse events being oral irritation (13%) and tooth sensitivity (6%). No participants discontinued product use because of a product-related adverse event.