Tooth whitening.

 Tooth whitening.

Tooth whitening or tooth bleaching is the process of lightning the color of human teeth. Teeth whitening involves bleaching your teeth to make them lighter. It can't make your teeth brilliant white, but it can lighten the existing colour by several shades. Tooth whitening can be a very effective way of lightening the natural colour of your teeth without removing any of the tooth surface. 

The natural tooth color :

The perception of tooth colour is multi-factorial. Reflection and absorption of light by the tooth can be influenced by a number of factors including specular transmission of light through the tooth; specular reflection at the surface; diffuse light reflection at the surface; absorption and scattering of light within the dental tissues; enamel mineral content; enamel thickness; dentine colour, the human observer, the fatigue of the eye, the type of incident light, and the presence of extrinsic and intrinsic stains. Additionally, the perceived brightness of the tooth can change depending on the brightness and colour of the background.

The combination of intrinsic colour and the presence of extrinsic stains on the tooth surface influence the colour and thus the overall appearance of teeth. The scattering of light and absorption within enamel and dentine determine the intrinsic colour of teeth and because the enamel is relatively translucent, the dentinal properties can play a major role in determining the overall tooth colour. On the other hand, extrinsic stain and colour is the result of coloured regions that have formed within the acquired pellicle on the enamel surface and can be influenced by lifestyle behaviours or habits.  For example, dietary intake of tannin-rich foods, poor tooth brushing technique, tobacco products, and exposure to iron salts and chlorhexidine can darken the colour of a tooth.

With increasing age, teeth tend to be darker in shade.  This can be attributed to secondary dentin formation and thinning of enamel due to tooth wear which contributes to a significant decrease in lightness and increase in yellowness. Tooth shade is not influenced by gender or race.

Who can do teeth whitning ?

Teeth whitening is a form of dentistry and should only be carried out by a dentist or another regulated dental professional, such as a dental hygienist or dental therapist, on the prescription of a dentist. Some beauty salons offer teeth whitening, but this is illegal if there's no dental professional present, and it may put your oral health at risk. You can also buy DIY home teeth whitening kits but these may also carry risks.

Procedure:

Prior to proceeding to tooth whitening alternatives, it is advised that the patient comes into the dental office to have a comprehensive oral examination that consists of a full medical, dental, and social history. This will allow the clinician to see if there is any treatment that needs to be done such as restorations to remove caries, and to assess whether or not the patient will be a good candidate to have the whitening done. The clinician would then debride (clean) the tooth surface with an ultrasonic scaler, hand instruments, and potentially a prophy paste to remove extrinsic stains. This will allow a clean surface for maximum benefits of whichever tooth whitening method the patient chooses. There is a various types of tooth whitening methods including both internal application of bleaching and external application through the use of bleaching agents.

1-In dental office :

Light-accelerated bleaching :

Power or light-accelerated bleaching uses light energy which is intended 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. Use of light during bleaching increases the risk of tooth sensitivity and may not be any more effective than bleaching without light when high concentrations of hydrogen peroxide are used.

 

Nanoparticle catalysts for reduced hydrogen peroxide concentration :

 A recent addition to the field is new light-accelerated bleaching agents containing lower concentrations of hydrogen peroxide with a titanium oxide nanoparticle-based catalyst. Reduced concentrations of hydrogen peroxide cause lower incidences of tooth hypersensitivity. The nanoparticles act as photocatalysts, and their size prevents them from diffusing deeply into the tooth. When exposed to light, the catalysts produce a rapid, localized breakdown of hydrogen peroxide into highly reactive radicals. Due to the extremely short lifetimes of the free radicals, they are able to produce bleaching effects similar to much higher concentration bleaching agents within the outer layers of the teeth where the nanoparticle catalysts are located. This provides effective tooth whitening while reducing the required concentration of hydrogen peroxide and other reactive byproducts at the tooth pulp.

Laser whitening :

Laser whitening, also known as power whitening, is another type of teeth whitening system that a dentist can provide. A bleaching product is painted onto your teeth and then a light or laser is shone on them to activate the whitening. Laser whitening takes about an hour.

Internal bleaching :

Internal bleaching is a process which occurs after a tooth has been endodontically treated. This means that the tooth will have had the nerve of the tooth extirpated or removed through a root canal treatment at the dentist or by a specialist endodontist. Internal bleaching is often sought after in teeth which have been endodontically treated as tooth discolouration becomes a problem due to the lack of nerve supply to that tooth. It is common to have this internal bleaching done on an anterior tooth (a front tooth that you can see when smiling and talking). A way around this is by sealing off the bleaching agent inside the tooth itself and replacing it every few weeks until the desired shade has been achieved. The amount of time between appointments varies from patient to patient and with operator preference until the desired shade has been achieved. Even though this is a great option, the disadvantage of this treatment is a risk of internal root resorption of the tooth that is being internally bleached. This may not occur in every patient or every tooth, and its occurrence is difficult to determine prior to completing the treatment.

 

2-At home :

Mouthguard :

The dentist will take an impression of your teeth to make a mouthguard and tell you how to use it with a bleaching gel. Then, using your mouthguard at home, you regularly apply the gel for a specified period of time over 2 to 4 weeks. Some whitening gels can be left on for up to 8 hours at a time, which shortens the treatment period to 1 week.

Whitening Toothpastes :

All toothpastes help remove surface stains, because they contain mild abrasives. Some whitening toothpastes contain gentle polishing or chemical agents that provide additional stain removal effectiveness. Whitening toothpastes can help remove surface stains only and do not contain bleach; over-the-counter and professional whitening products contain carbamide peroxide or hydrogen peroxide that helps lighten the color deep in the tooth. Whitening toothpastes can lighten the tooth's color by about one shade. In contrast, prescription strength whitening conducted in your dentist's office can make your teeth three to eight shades lighter.

Over-the-Counter Whitening Strips and Gels :

Whitening gels are clear, peroxide-based gels applied with a small brush directly to the surface of your teeth. Instructions vary depending on the strength of the peroxide. Follow the directions on the product carefully. Initial results are seen in a few days and final results are sustained for about four months.

Whitening strips are very thin, virtually invisible strips that are coated with a peroxide-based whitening gel. The strips should be applied according to the instructions on the label. Initial results are seen in a few days and final results are sustained for about four months.

Whitening Rinses :

Among the newest whitening products available are whitening rinses. Like most mouthwashes, they freshen breath and help reduce dental plaque and gum disease. But these products also include ingredients, such as hydrogen peroxide in some, which whiten teeth. Manufacturers say it may take 12 weeks to see results. You just swish them around in your mouth for 60 seconds twice a day before brushing your teeth. However, some experts say that rinses may not be as effective as other over-the-counter whitening products. Because a whitening rinse is only in contact with the teeth for such a short time -- just two minutes a day compared to 30 minutes for many strips -- it may have less of an effect.

Tray-based :

Tray-based tooth whitening is achieved by wearing a fitted tray containing carbamide peroxide bleaching gel overnight or for two to four hours a day. If manufacturer's instructions are followed, tooth whitening can occur within three days and lighten teeth by one or two shades. This type of tooth whitening is available over-the-counter and professionally from an oral health professional.

 

sUMMARY :

A healthy diet with enough calcium can help prevent your teeth from becoming yellow. Brushing your teeth soon after you eat can also help prevent stains. Certain fruits may have properties that help whiten teeth. Regularly consume raw fruits and vegetables to help rub off plaque and keep your teeth looking bright.

Daily brushing and flossing, along with regular cleanings at the dentist’s office, prevent the buildup of yellowing plaque on your teeth.