What is the Best Professional Teeth Whitening?

The only difference in the hundreds of dentist-prescribed whitening systems out there is the concentration of the gel (oxygenating agent) and the way it is applied to your teeth.
There are two main ways of carrying out tooth whitening:

Tray based whitening. The gel is placed in a custom made night-guard which is worn for a set period for 10-14 days. The period you wear the trays depends on the type and concentration of peroxide gel.
In-surgery whitening, also known as laser or power bleaching. Here, more concentrated gels are applied directly to the teeth and accelerated with heat or light (laser/power). We still make custom-made trays for the patient to use afterwards to maximise the whitening and for maintenance.

Sensitivity to laser/power bleaching is usually only for the rest of that day. We suggest avoiding very hot or cold foods. Take whatever medication you would take for a headache and if you have custom-made trays place some sensitive toothpaste in the trays and wear for 10 minutes.

There are many whitening agents available, but buyer beware!  Because these products are considered a cosmetic and not subject to FDA testing, there are products that will damage the tooth structure.  Buying products over the counter or even from your dentist does not guarantee it is safe.  That being said, there are safe products that will whiten and not damage the teeth.  The basic formula for successful whitening is time in contact with teeth and concentration of the whitening agent.  Using heat and light to "activate" gel increases trauma to the pulp of the tooth and has not been shown to improve whitening over gel alone. The easiest on the tooth is a low concentration of carbamide peroxide over a long time.  This can be done safely using a tray system of whitening.

The best option is always to get it assessed by the dental professional for exact cause of discolouration and best solution. Home whitening has traditionally proved to be the best of all.