Dr. Ryne Johnson
, prosthodontist and managing partner of Newton Wellesley Dental Partners
was recently interviewed for a national magazine that was developing a synopsis of cosmetic dental procedures. According to Dr. Johnson
, “Tooth whitening has become one of the most frequently requested dental procedures in his office. The public has come to demand whiter, more perfect smiles and in response many choices for tooth whitening have been made available. These include home-based products such as toothpastes, gels, and films, as well as in-office based systems where products containing highly concentrated bleaching agents are applied under professional supervision". The profession and public have been aware of certain risks related to tooth whitening such as increased tooth sensitivity and gingival irritation. New research has shown that there are other risks such as tooth surface roughening and softening, increased potential for demineralization, degradation of dental restorations, and unacceptable color change of dental restorations. The new research is also focused on optimizing whitening procedures to reduce tooth sensitivity and to increase the persistence of the whitening.
Types of Teeth Whitening Systems
Whitening systems can be variously categorized. The following approach is in accordance with the American Academy of Cosmetic Dentistry.
Whitening toothpastes typically contain higher amounts of abrasives and detergents than standard toothpastes, to remove tougher stains. Whitening toothpastes do not contain bleach (sodium hypochlorite) but some contain low concentrations of carbamide peroxide or hydrogen peroxide that help lighten tooth color. Whitening toothpastes typically can lighten tooth color by about one or two shades.
OTC Whitening Strips and Gels
Whitening strips were introduced into the market in the late 1980’s. They deliver a thin layer of peroxide gel on plastic strips shaped to fit onto the buccal surfaces of the teeth. There are a variety of white strip products on the market with varying instructions. A typical set of instructions are to apply the strips twice daily for 30 minutes for 14 days.
Tooth lightening can be seen in several days and this method can lighten the teeth by 1 or 2 shades. There are some newer whitening strip products that require only one 30-minute application per day that have the same whitening end point as the two-a-day products.
Whitening gels are peroxide-based gels applied with a small brush directly to the surface of the teeth. Manufacturer’s instructions are usually twice a day applications for 14 days. Like the whitening strips, the teeth can usually be lightened by 1 or 2 shades.
Whitening rinses contain oxygen sources such as hydrogen peroxide to react with the chromogens.
Manufacturer’s instructions are for twice a day rinsing for 60 seconds each. It takes up to 3 months to see a 1 or 2 shade improvement in tooth color.
Tray-Based Tooth Whiteners
Tray-based tooth whitening systems are available both professionally and OTC. This method involves use of a fitted tray containing carbamide peroxide-bleaching gel worn f
or 2 to 4 hours a day or overnight. Usually by following the manufacturer instructions tooth whitening is noticeable in a few days, lightening the teeth by 1 or 2 shades.
Quicker tooth lightening can be achieved through in-office whitening because the products deliver higher concentrations of peroxide than OTC. Consequently, gingival tissues are usually protected before the agent is applied. Some products claim to increase the oxidation of chromogens by exposure to heat or an intense blue light with a wave length between 480 nm and 520 nm to activate the product while on the tooth, causing the chemical reactions to proceed faster. Some professionals use laser systems to increase the rate of the chemical reactions. This use of lasers is considered to be an ‘off-label’ use of laser systems in dentistry by the US Food and Drug Administration. In a systematic review by Buchalla and Attin no added benefit from light-activated systems was found and thus the American Dental Association does not endorse such whitening systems.
Tooth lightening results are seen after one 30- to 60-minute treatment. More dramatic results can be obtained with several applications.
Risks associated with Tooth Whitening
Risks commonly reported with tooth whitening include increased tooth sensitivity and mild gingival irritation. The degree of these side effects is directly related to the concentration of the peroxide bleach component, duration of the treatment, and the non-bleach composition of the product used. Tooth sensitivity usually occurs at the time of treatment and can last several days; gingival irritation begins within a day of the treatment and can also last several days. There are additional risks that have been reported from in
vitro studies which include tooth erosion, tooth mineral degradation, increased susceptibility to demineralization, and pulpal damage.4
The ultimate endpoint for tooth whitening is dependent upon the tooth itself, with common wisdom telling us that all treatment regimens will eventually arrive at the same whitening endpoint. This is not exactly true as some very aggressive regimens can damage the tooth through dehydration and demineralization such that the tooth temporarily appears whiter.
Dr. Ryne Johnson, who first lectured on tooth whitening procedures in 1989, has helped thousands of patients achieve a more beautiful smile, often incorporating this proven technique.
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Original article: https://www.ncbi.nlm.nih.gov