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How Whitening Works

Course Number: 657

Design Principles for Oxidative Tooth Whitening: Factors Affecting Safety to Hard Tissues and Restorations

Following the development and publication of the nightguard vital bleaching technique, an explosion of research focused on the safety of the oxidizing agents from various products to tooth enamel, dentin and restorative materials.62-67 This research has established that tooth bleaching is typically safe for hard tissues and restorative materials, particularly in systems developed by reputable manufacturers. Four aspects of hard tissue safety warrant continued follow up.

First, professionals must realize that bleaching does not provide intrinsic whitening to restorative materials such as tooth crowns or veneers. Although bleaching may certainly whiten stains on crowns/veneers/restorations it will not change the shade of the crown material itself. Patients should be bleached before restorative work is undertaken and the color should be matched to the bleached teeth. It is important that dental professionals counsel patients about this if they are considering OTC oxidative whitening.68-71

Second, when bleaching is performed prior to restorative work – the teeth should be allowed to equilibrate for a time period (several weeks to a month) prior to placing restorations. Research has shown that restorative adhesion is marginally reduced immediately after tooth bleaching, and a 2-week period of recovery can compensate for this phenomenon.72-75

Third, professionals should follow closely patient response to bleaching to assess effects of dental hypersensitivity on the patient’s hygiene practices. Patients may benefit for short periods from utilization of hygiene products which may reduce sensitivity during and following bleaching procedures.75-78

Lastly, professionals should follow up patients to assess color stability following their bleaching treatments. Numerous products are available which can be used to touch up teeth which may not retain color stability permitting local treatment. For consumers who exhibit habits (e.g., smoking) which may stain teeth following whitening – it is recommended that they maintain their tooth color with whitening toothpastes or rinses, a number of which provide excellent efficacy for the prevention of the development of tooth stains.79-84