Teeth Whitening – type of procedures, risks and Benefits

Who does not wish to have whiter and brighter teeth! A bright sparkling smile can be a real kick to your self confidence. Yellow teeth may tarnish your personality. One of the least invasive way to get ‘pearly white’ teeth is tooth whitening treatment or bleaching.

A wide array of options are available for teeth whitening or to improve tooth  colour such as Professional cleaning and polishing to remove stains,Whitening toothpastes,Internal bleaching of non-vital teeth,External bleaching of vital teeth, Micro-abrasion of enamel, Crowns or veneers. However, your dentist is the best person to tell you, what is good for your discoloured teeth.

Composite or ceramic veneers/crowns and tooth-whitening or bleaching are two most commonly used procedures for the treatment of discoloured teeth. However, the placement of veneers or crowns is an invasive procedure and requires removal of sound tooth structure. It is also relatively expensive and time consuming. On the contrary, tooth-whitening is minimally invasive requiring no removal of tooth structure, cheaper and less time consuming.

What is Teeth Whitening?

The composition of tooth structures will affect the outward appearance of a tooth. Teeth is made up of  three layers: Enamel, dentin and pulp from outward to inward.

Normally, outermost enamel layer is colorless and translucent. Colour of dentin is yellowish. The color of natural teeth is determined by the color and diffuse reflectance of dentin, and the thickness and light scattering effect of enamel. This is termed the “double-layer effect”. 

Teeth whitening involves breaking down the discolouration so that your teeth look whiter. Whether the process will work for you depends largely on the cause of your discolouration.

Therefore, any structural changes  in the enamel, the dentin or the pulp, the light transmitting and light reflecting properties of a tooth are likely to be altered, thus the appearance of your teeth too. Color of a tooth is affected predominantly by dentin and the translucency of enamel acting as a color modifier.

2 Types of tooth discolouration stains

1. Extrinsic stains
   These stains are caused by extrinsic factors and can be divided into two categories.
   • Some compounds may get incorporated into pellicle in your teeth and produce a stain as a result of their basic color or chromogens in your diet or substances habitually placed in the mouth
   • Some other compounds may be caused by chemical interaction at the tooth surface.

   The majority of tooth discoloration are extrinsic in nature and appear as brown integuments.

2. Intrinsic stains
   Factors for intrinsic staining is present within body either congenital (since birth) or systemic.

Risks associated with teeth whitening

Teeth whitening is generally safe when used in the correct way. One of the biggest risks associated with teeth whitening arises when it is applied incorrectly or by someone who is not properly qualified.

Two most common risks associated with teeth whitening are:

• Tooth sensitivity
• Gingival or mucosal irritation
• If you have dental fillings, often the expense and/or the risks related to the replacement fillings or crowns to match post-bleaching tooth color may contraindicate bleaching
• Throat irritation and nausea

Procedures available for Tooth whitening

1. Non-vital tooth bleaching
   Non-vital bleaching as the name indicates is for non-vital teeth (dead pulp) and vital bleaching is for vital teeth.In non-vital bleaching involves placing a a medicament  inside tooth (pulp chamber) for 3 to 7 days or bleaching material can be applied both externally and internally known as inside/outside technique.
2. External or vital tooth bleaching
   1. Dentist-supervised home bleaching
      • Dentist-supervised home bleaching or night guard vital bleaching has become the most commonly used whitening technique.
      • This procedure uses custom made trays incorporating  bleaching agent, 10% Carbamide peroxide aimed to be used at home in night.
      • Carbamide peroxide disintegrates into hydrogen peroxide, responsible for bleaching action.
      • Effective for bleaching teeth stained by aging, mild fluorosis, trauma, inherent discoloration and tetracycline staining.
      • You need to wear nightguard for at least 2 weeks.
      • Compliance and motivation are two important things for success rate of nightguard treatment.

        What are the benefits of at-home bleaching
        

        • Relative low-cost
        • less chairside tume
        • High success rate
        • Ease of use
        •  Safe
   2. In-office bleaching or Power bleaching
      • Power bleaching has been regarded as a reliable technique for rapid lightening of discoloured teeth within a short span of time.
      • Ideal for use in specific situations such as severe discolouration, discolouration of a single tooth, lack of  patient  compliance or if a rapid treatment is desired.
      • In office bleaching, usually a high concentration of hydrogen peroxide 30-50%. This is done with proper soft tissue protection by the dentist.
      • Bleaching may need multiple sitting depending upon extent of discolouration and results desired, each sitting may last for  30 to 60 minutes.
   3. Combination or Assisted Bleaching
      Combination of in office and night guard bleaching techniques for rapid whitening of teeth that can be used to motivate the patient to continue with at-home bleaching and patient compliance is not a problem.The patient wears a custom fitting tray filled with bleaching material and is requested to sit in the waiting room for about 30 minutes to an hour. The gel is rinsed off the teeth after the time has elapsed. The procedure is also known as “waiting room bleach”.

What is the best time for teeth bleaching?

The length of treatment and expected outcome will depend on the cause of the discoloration, as well as the chosen product and technique.

Success will vary when tooth discoloration is related to inherited/ developmental aspects, age-related tooth changes, extrinsic staining (e.g., from diet or smoking), or intrinsic staining such as tetracycline-associated stain or color change secondary to tooth trauma.

External tooth discoloration is highly responsive to bleaching.

Tooth stains caused by aging, genetics, smoking, or coffee are the fastest to respond to bleaching: Yellowish aging stains respond quickly to bleaching in most cases, whereas blue–gray tetracycline stains are the slowest to respond to bleaching.

With tray bleaching, teeth normally lighten in 3 days to 6 weeks. However, whitening of  nicotine-stained teeth may take 1-3 months. Tetracycline-stained teeth may respond 2 to 6 months (or more).

Why my teeth are yellow and not shinning?