The Science of Teeth Whitening
SUMMARY: With cavities and unsightly gums less of a concern, more dental patients have turned their attention to improving their overall appearance with teeth whitening. Cosmetic treatments have become the most common service requests from dental patients, with more than ten million Americans spending $1.7 billion a year on teeth whitening products and services.
Posted: December 19, 2011
With cavities and unsightly gums less of a concern, more dental patients have turned their attention to improving their overall appearance with teeth whitening. Cosmetic treatments have become the most common service requests from dental patients, with more than ten million Americans spending $1.7 billion a year on teeth whitening products and services.
Teeth whitening refers to “any procedure that changes the shade and appearance of teeth without using restorative materials” (1). This includes products dispensed by dental professionals and over-the-counter products. Studies have shown patients who feel good about their physical appearance tend to adjust to illnesses better and experience shorter recuperation times. The semi-clear, but hard outer layer tooth surface consists of enamel, which provides protection for the dentin.
In 1951, a study revealed that radioisotope-labeled hydrogen peroxide could penetrate enamel to the dentin pulp. Hydrogen peroxide makes up the main ingredient in many tooth whitening products (1, 2). Other whitening products contain carbamide peroxide. The tooth enamel is made of hydroxyapatite crystals. The formation of microscopic hexagonal rods makes the tooth enamel porous. The teeth change color due to the penetration of staining agents into the enamel, which makes it a challenge to clean the otherwise harmless stains from the tooth surface.
Causes of Teeth Discoloration
The success of teeth whitening treatments has as much to do with the type, intensity and location of the discoloration. The diagnosis performed by the dental professional represents the most important aspect of addressing tooth discoloration issues. The dentist’s evaluation determines if the discoloration lies in the enamel surface or is a deeper staining, which affects the tooth’s structure. The tooth whitening process requires dentists to identify “the etiology of tooth discoloration” as it relates to the patient. The dental professional must also diagnose the cause of the staining and develop an appropriate treatment plan (1).”
Extrinsic causes of discoloration include: ingested food, cigarettes, coffee, wine and tea. Plaque buildup on the top enamel will also discolor the patients’ teeth.
Intrinsic or systematic conditions, such as amelogenesis imperfecta can result in hypoplasia-- a condition signified by hypocalcification with yellow or brown stains on the teeth. Dentinogenesis imperfecta causes brownish-violet, yellowish, or gray discolorations. Hypoplasia also occurs because of cerebral palsy, serious renal damage, severe allergies or clefting of the lip.
Cavities and coronal materials used in the oral cavity may also lead to tooth discoloration. As a person ages, the semi- translucent tooth enamel becomes thinner. The darker dentin layer, underneath the enamel, makes the tooth appear darker (1, 2, 3).
Teeth Whitening Systems
Tooth whitening systems rely on bleaching compounds, such as hydrogen peroxide or carbamide peroxide to penetrate tooth enamel and remove stains. Each one of these chemicals produce an oxidation reaction that attacks staining compounds, breaks them apart and leaves the teeth whiter. Carbamide peroxide works as it reduces to hydrogen peroxide and urea. The hydrogen peroxide then serves as the whitening agent.
Teeth whitening products includes a broad range of items: bleaching products, tooth whitening toothpastes, dental prophylaxis professional vital and non-vital bleaching and denture cleaners. The products have different concentrations of hydrogen peroxide or carbamide peroxide, depending on the type of system and type of teeth being whitened. Most teeth whitening treatments take place in a dental office where it is prescribed by a dentist and administered by a dental technician. The prescribed teeth whitening treatment may also be supervised at home, or a combination of both at-home and in-office treatment protocols.
In-Office - This is the most popular teeth whitening treatment method and entails a heated or non-heated solution comprised of 15, 30 or 35 percent volume of a hydrogen peroxide whitening agent. Patients experience quick results, but this method requires multiple visits to complete the application. Most dentists prefer this method because they can control and monitor treatment.
Take Home – Patients who prefer to perform the treatment at home, or are working on a budget may choose the “take home” method of teeth whitening, which takes place over a 2 to 4 week period depending on the level of discoloration. The dental technician will first formulate a tray from soft plastic called a night-guard, which based on a model of the patient’s teeth. Once the mold of the mouth and teeth has been created, the trays will be produced and contains a solution of 10 to 22 percent carbamide peroxide gel. When at home, the patient will seat the tray over the teeth for two hours, once or twice a day. When using this method, it is important to stay diligent and apply the treatment as instructed. If the application is not consistent, the desired results may not be generated, leaving the person with the same stained teeth.
Take Home TheraBreath® Solution
TheraBreath recommends the TheraBrite® Formula Whitening Kits for effective at-home teeth whitening. The teeth whitening kit contains thermoplastic mouthguards which mold to the contours of your teeth and gums. The kit also comes with a 21%+ carbamide peroxide gel to deliver the fastest at-home whitening treatment available. Click here to purchase the TheraBrite PLUS Whitening Kit.
Combination Technique - This blend of in-office and at-home treatment reduces the total time required, and the number of office visits needed to complete the teeth whitening process. This method also elicits the highest customer satisfaction level. It entails a one hour treatment with a 35 percent hydrogen peroxide solution. The take-home portion of the treatment covers five days. A second in-office application completes the treatment protocol.
Whitening Strips - The whitening strips consist of polyethylene strips filled with a 5.3 percent hydrogen peroxide solution. Used for 30 minutes, twice a day, this treatment usually entails maintenance for patients who have completed the in-office or supervised in home treatment. However, many patients who do not have the financial resources for more expensive whitening treatment or wish to avoid the inconvenience prefer this option (6).
Light-Activated Whitening Systems- Light activated teeth whitening systems when used with a light activated whitening gel, trigger a chemical bleaching reaction that makes teeth brighter. The light-activated whitening systems may be adjusted for intensity to improve comfort for patients with sensitive teeth. When the engaged, the blue light-emitting diodes penetrate the teeth to remove deep stains and discoloration. The gel used with light-activated systems generally contain an active ingredient of hydrogen peroxide, which is broken down and allows oxygen to enter the enamel and dentin, removing the stains. Using the light helps the hydrogen peroxide penetrate the surface of the teeth.
Whitening Toothpaste – Although the commercial market has been flooded with toothpastes claiming whitening abilities, only a few actually show the ability to remove stains effectively. Reasons that the whitening toothpaste may be ineffective include:
- Insufficient contact time with the teeth.
- Small amount of abrasive material required to remove stains.
- Minimal exposure to actual stains.
TheraBreath created TheraBrite PLUS toothpaste as an effective teeth whitening tool. This product with was developed by Dr. Katz combines portions of the PLUS formula with Diatomaceous whitening agents to maintain a white, bright and healthy smile. Click here to learn more about this great whitening toothpaste product.
The TheraBreath teeth whitening protocol recommends patients who select an in-home teeth whitening treatment to brush their teeth for two minutes with an oxygenating toothpaste before bleaching.
People across all age ranges are choosing over-the-counter (OTC) solutions to whitening their teeth. OTC products come in the form of trays, whitening dentifrices, whitening strips, and paint on brush treatments. The patient must use either a semi mold tray or a prefabricated tray filled with a whitening agent. The limitation of OTC treatments concern the fit of trays and the teeth whitening solution mixture potency (6).
Toxicity and Side Effects of Teeth Whitening
Studies have shown patients should not exceed more than 10 mg/kg of carbamide peroxide on a daily basis (10). The studies concerning the toxicity of hydrogen peroxide are conflicting. Some researchers believe the oxidation process may have links to carcinogens, stroke, aging, liver disease and other maladies, however this research is still inconclusive. As side effects of teeth whitening procedures and products, the patient may experience sensitive teeth and ulceration of the mouth. (3, 8, 9).
TheraBrite Formula Whitening Kits do not contain glycerin. Glycerin in teeth whitening products causes teeth sensitivity. Also, mixing glycerin with carmabide peroxide (one of the primary ingredients in teeth whitening products) pulls water out of the tooth enamel. This removal of water from the enamel may accelerate the bleaching process, but also leads to the sensitivity many patients experience. Conclusion Teeth whitening has become an effective treatment that can dramatically change a patient’s appearance. Patients receive satisfaction from professionally dispensed teeth whitening treatment and OTC products. When performing in-office treatments, dentists should discuss with patients the procedure and what they should expect. Dentists should also remind patients to avoid using in-home treatments when undergoing in-office bleaching. This could affect in-office color matching or bonding. To get started, click here to visit the TheraBreath Teeth Whitening Products page.
1 Gerard Kugel, DMD, et al. 2006. “ The Art and Science of Tooth Whitening.” http://www.dentalaegis.com/id/2006/09/focus-on-the-art-and-science-of-tooth-whitening. September 2006.
2 Bonnie Craig, Tooth Whitening, Efficacy Effects and Biological Safety http://www.cdha.ca/pdfs/Education/Scene/volume33_6_page5.pdf.” Probe Scientific Journal, November/December 1999.
3 Ronald Goldstein, et al. “The Current Status of CE 3 Vital Tooth Whitening Techniques.” http://www.vanhaywood.com/articles/pdf/currentstatuswhiten.pdf . Compend Contin Educ Dent. 1999.
4 TAO HE, et al. “ randomized clinical study to assess the extrinsic staining profiles of stannous- and triclosan-containing dentifrices.” http://www.dentalcare.com/media/en-US/research_db/pdf/cphr/article%204%20AJOD%20Sept.pdf.
5 Gianluca Plotino, DDS, “Nonvital Tooth Bleaching: A Review of the Literature and Clinical Procedures.” http://www.endoexperience.com/documents/BleachingJOE2008.pdf
7 Kishi A, et al. “Effect of light units on tooth bleaching with visible-light activating titanium dioxide photocatalyst.” http://www.ncbi.nlm.nih.gov/pubmed/21946494 .Dent Mater J. 2011;30(5):723-9. Epub 2011 Sep 23.
8 Sharif N, et al. 2000. “The chemical stain removal properties of “whitening” toothpaste products: studies in vitro.” ww.ncbi.nlm.nih.gov/pubmed?term=“The chemical stain removal properties of “whitening.” toothpaste products%3A studies in vitro. Br Dent J. 2000
9 E Firat, et al. “The Effect of Bleaching Systems on the Gingiva and the Levels of IL-1ß and IL-10 in Gingival Crevicular Fluid.” http://www.jopdentonline.org/doi/abs/10.2341/10-058-C?journalCode=odnt. Operative Dentistry November/December 2011.
10 E. Dahl and R. Becher “Acute Toxicity of Carbamide Peroxide and a Commercially Available Tooth-bleaching Agent in Rats.” http://jdr.sagepub.com/content/74/2/710.full.pdf Journal research.1995
11 Howard E. Strassler, DMD. “Vital Tooth Bleaching An Update.” http://www.dental.umaryland.edu/z_dental_archives/dentalprograms_old/ce/Vital%20Tooth%20Bleaching%20an%20Update%20by%20Strassler.pdf.
12 Li Y, “Toxicological considerations of tooth bleaching using peroxide-containing agents.” http://www.ncbi.nlm.nih.gov/pubmed?term=Toxicological%20considerations%20of%20tooth%20bleaching%20using%20peroxide-containing%20agents. Northwest Dent. Nov-Dec 2010. 13 Perdigão J.”Dental whitening--revisiting the myths.” http://www.ncbi.nlm.nih.gov/pubmed/21287813
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