Page 108 - Journal of Laser Dentistry 1

chemical burns to the soft tissues. The bleaching agent is either carbamide peroxide, which breaks down in the mouth to form hydrogen peroxide, or hydrogen peroxide itself. The bleaching gel typically contains between 10% and 44% carbamide peroxide (15% is recommended), which is roughly equivalent to a 3-10% hydrogen peroxide concentration.

Low-concentration whitening is far less effective, and is generally only performed at home. Low-concentration whitening involves purchasing a thin mouthguard or strip that holds a relatively low concentration of oxidizing agent next to the teeth for as long as several hours a day for a period of 5 to 14 days. Results can vary, depending on which application is chosen, with some people achieving whiter teeth in a few days, and others seeing very little results or no results at all. Whitening is potentially better at a dentist because the strip or mouth-guard does not completely conform to the shape of the teeth, sometimes leaving the tips of the teeth (near the gumline) unbleached. The bleaching agent is typically less than 10% hydrogen peroxide equivalent, so irritation to the soft tissue around teeth is minimized. Dentists as well as some dental laboratories can fabricate custom fitted whitening trays that will greatly improve the results achieved with an over-the-counter whitening method.

A typical course of bleaching can produce dramatic improvements in the cosmetic appearance of most stained teeth; however, some stains do not respond to bleaching. Tetracycline staining may require prolonged bleaching, as it takes longer for the bleach to reach the dentine layer. Case studies have been performed on people with tetracycline stained teeth. They used custom bleaching trays every night for 6 months and saw dramatic results and improvement. White-spot decalcifications may also be highlighted and become more noticeable directly following a whiting process, but usually calm back down with the other parts of the teeth becoming more white. The white spots become less noticeably with the other parts of the teeth becoming more white0. Bleaching is not recommended if teeth have decay or infected

gums. It is also least effective when the original tooth color is grayish and may require custom bleaching trays. Bleaching is most effective with yellow discolored teeth. However, whitener does not work where bonding has been used and neither is it effective on tooth-color filling. Other options to deal with such cases are the porcelain veneers or dental bonding.

Although there is a wide range of whitening products and techniques available, the results after using them may vary from very positive results to almost non-existent results.

The whitening shade guides are used to measure tooth color with Vitapan Classic Shade Guide being the most widely used with 16 shades. These shades determine the effectiveness of the whitening procedure, which may vary from two to seven shades.

Power or light-accelerated bleaching, sometimes colloquially referred to as laser bleaching, uses light energy to accelerate the process of bleaching in a dental office. Different types of energy can be used in this procedure, with the most common being halogen, LED, or plasma arc. Clinical trials have demonstrated that among these three options, laser light is the best source for producing optimal treatment results. The ideal source of energy should be high energy to excite the peroxide molecules without overheating the pulp of the tooth. Lights are typically within the blue light spectrum as this has been found to contain the most effective wavelengths for initiating the hydrogen peroxide reaction. A power bleaching treatment typically involves isolation of soft tissue with a resin-based, light-curable barrier, application of a professional dental-grade hydrogen peroxide whitening gel (25-38% hydrogen peroxide, 150 Volumes), and exposure to the light source for 6–15 minutes. Recent technical advances have minimized heat and ultraviolet emissions, allowing a less time-intensive patient preparation procedure. Most power teeth whitening treatments can be done in approximately 30 minutes to one hour, in a single visit to a dental physician. Treatment times and recommendations are