Tooth whitening continues to be the number one cosmetic procedure requested by patients of all ages. Americans are spending over 1.4 billion annually on over the counter tooth whitening products. Professional tooth whitening is safe, effective, desired by our patients and the most conservative cosmetic treatment we can offer.
Tooth color is determined by several factors. Both the enamel and the dentin play roles in the determination of what color is seen in the oral cavity. Both the enamel and the dentin are formed by millions of tiny crystals in a lipid/protein matrix.
Enamel is the hardest substance in the body. The thickness of healthy enamel varies by tooth. Enamel is thinnest on incisors (about 2 mm) and thickest on molars (2.5 to 3 mm).
It is composed primarily (about 95%) of calcium phosphate molecules that are packed so tightly together that they are known as apatite crystals. Apatite crystals have often been called hydroxyapatite, which means it has attached oxygen and hydrogen groups, however pure hydroxyapatite does not really exist. Tooth mineral is more like contaminated carbonated hydroxyapatite.
If fluoride ions replace some of the oxygen and hydrogen ions in the crystal, it becomes fluorapatite. Fluorapatite forms a stronger crystalline lattice and is more resistant to acid attack.
All these crystals in the matrix line up into a cluster that is perpendicular to the tooth surface and is known as enamel rods. There are tiny spaces between the crystals and fluids that fill the spaces (protein, lipids, and water) between the rods. Although these spaces are too small for bacteria to enter, other ions such as oxygen, hydrogen, fluoride, and calcium phosphate can enter. If the enamel is demineralized, it provides a more porous area for the carious process.
The natural color of the teeth comes from both the enamel and the underlining dentin. This color can range from a yellowish-white to grey. The color of the dentin is a major contributor to overall tooth color. Genetically determined, dentin color ranges from yellowish-white to grayish-white.
Dentin is the largest tooth structure. It is calcified with tubules filled with plasma-like fluid, much like the enamel. As living tissue, dentin conducts thermal sensitivity and pain from enamel to the nerve root, resulting in hypersensitivity.
Changes in tooth color can occur through several different means. They can be extrinsic or exogenous due to things such as food, drinks, tobacco, and drugs. They usually adhere to the tooth deposits but can also adhere to the tooth structure itself.
Intrinsic, or endogenous stains can also cause color changes within the tooth. These include staining from aging, oral disease, trauma, medications, systemic conditions, and heredity.
As teeth grow older, the pulp shrinks and the dentin becomes thicker, which can cause teeth to look more yellow. Oral diseases, such as exposed root surfaces from gingival recession or restorations, also affect tooth color.
During trauma, vital pulp tissue can die. If a trauma does not destroy the tooth, bleeding into tooth structures can occur causing darkening over time. Enamel defects can result from trauma during tooth formation or inherited dental disorders, such as amelogenesis imperfecta.
Medications taken during tooth formation can result in enamel defects. A common cause is an antibiotic tetracycline. Fluorosis, or excess fluoride consumption, can also cause mottled and spotted teeth, as shown here.
If a patient wants to make them brighter and whiter, this can be achieved. There are several options to choose from in the office, from the office and over the counter (OTC).
The OTC industry has seen the evolution of gels, strips, rinses and chewing gum. The OTC products have produced oral health concerns resulting from undiagnosed or underlying oral health problems. Faders such as dental restorations, extremely dark stains, tooth sensitivity, non-uniform single tooth color difference, cavities, periodontal (gum) problems, exposed tooth-root surfaces, prior root canals, and antibiotic influenced internal colors have all contributed to the varying success of the expended whitening results. The incidence and varying degrees of tooth sensitivity may depend on the bleaching material quality, operator, and applied techniques. Since consumers rarely report adverse problems to the FDA, the American Dental Association advises patients interested in bleaching to consult with their dentist prior to bleaching to help determine the most appropriate method, based on desired results and safety.
In-office whitening (bleaching) materials are typically hydrogen peroxide-based, while some products are carbazide peroxide based. The strength of the in-office bleaching product range typically 3-5 times more concentrated than at-home bleaching materials. Regarding the sensitivity of teeth while using the products, mild to high tooth sensitivity can occur in up to two-thirds of users during the early stages of treatment, with the duration of sensitivity individual. The occurrence and severity of tooth sensitivity and gum irritation may depend on the material brand, quality, technique, duration of applications, and chemical concentrations of products.
As a general consideration of bleaching. patients should begin with a general dental examination that includes health and dental history, along with radiographs. If there is discoloration of teeth, due to favors such as trauma and/or staining resulting from prolonged use of antibiotics, such as tetracycline, the whitening expeditions of the patient may be unachievable without cosmetic
restorative treatment. Past history of tooth sensitivity and allergies, such as ingredients found in the bleaching materials, are all factors to bleaching. Cracks in tooth enamel exposed root surfaces that resist bleaching (and may increase sensitivity), the translucency of the teeth edges, tooth anatomy and alignment, teeth grinding/clenching habits and diets are also considerations that will influence the whitening outcome. if dental restorations are present, the expense and risks related to the replacement of fillings and/or crowns to match post-treatment colors should be recognized and discussed before treatment begins. Smoking and
red wine consumption will influence the duration and outcome of the whitening experience. Age is also a consideration, as teeth typically darker as we get older.
With tray bleaching, the desired color change is normally seen in the 3 days to 6-week range. Although brown, beige, and light yellowed teeth may respond well to bleaching, white discolorations and grey tooth shades may remain difficult to change. The “background” of the white spots may be lightened to make the white areas less noticeable. Nicotine stained teeth and tetracycline influenced grey teeth may take months to see a color change. Tray systems available from a dental office may have longer-lasting results, safer regarding concentrations of materials, and more control of bleaching gels than OTC tray systems.
With in-office bleaching, proper isolations of soft tissue, such as gums and tongue, is very important. Post-treatment sensitivity is unpredictable. There are some studies that have suggested pulp irritation and tooth sensitivity may be higher with the use of bleaching lights or procedures involving applying heat. Some
studies suggest heat and light application may initially increase whitening appearance due to tooth dehydration, which usually reverses with time. Some studies suggest that the average number of in-office visits for whitening is three, with the range of 1-6 treatments. A tray may be made for take home completion of this process.
Presently, all non-internal tooth bleaching products remain unclassified by the FDA, These products include all in-office peroxide-based products, at-home dentist dispensed products, OTC products, as well as materials used in nondental stores (such as retail stores). Tooth whitening products are developed and marketed under U.S. “cosmetic” regulations.
While there are some side effects mentioned above from teeth whitening, most conventional whitening treatments are fairly safe to use as long as the product’s directions or procedures are followed.
Tooth Whitening has become easy, rewarding, and profitable. New systems are being brought to market at a dizzying pace so it is important to stay up on current methods and industry knowledge.