For information about tooth discoloration of teeth, please refer to "Discoloration of Teeth" of "Oral Problem".
Bleaching can only turn your teeth white for a period of time, and the length of this period differs by individual. You need to visit the dentist repeatedly for bleaching treatment in order to keep your teeth white. Please ask your dentist for more information about the duration of treatment and how long the effect lasts before you decide to receive treatment.
For more information about teeth bleaching, please click here.
At present time, only a limited number of private dental clinics offer laser whitening treatment. You can try to enquire registered private dentists. The link below is a list of all registered dentists in Hong Kong.
https://www.dchk.org.hk/en/list/list.htm
Most of the over-the-counter teeth bleaching agents contain some chemical substances or coarse particles that can damage the surface of teeth, therefore we shouldn't thoughtlessly use them. Moreover, bleaching agents contain a high concentration of hydrogen peroxide and other substances, and misuse of the agent can cause harmful effects to the gums. It can also cause serious harm to the body if it is ingested by mistake. Therefore, teeth whitening agents should only be used under dentist's supervision.
Tooth bleaching agents can only whiten the teeth for a period of time, and length of time differs by individual. You need to visit the dentist repeatedly for bleaching in order to keep your teeth white.
Please refer to the sections on "Tooth whitening agents" and "Bleaching" of this website, and leaflet "There is always a way to whiten your teeth".
Generally speaking, the colour of permanent teeth is slightly yellowish. This is the colour of the dentine under the enamel, and whitening is not necessary in this situation. If you feel that your teeth have turned yellowish, maybe you haven't thoroughly cleaned your teeth when you brushed. It is most desirable if you receive a check-up and scaling from your dentist.
The over-the-counter bleaching agents contain a high concentration of hydrogen peroxide and other substances, and misuse of the agent can be harmful to the gums. It can also cause serious harm to the body if it is ingested by mistake. Therefore, tooth whitening agents should only be used under dentist's supervision.