Is there a form of in-practice whitening that lasts more than 12 months?

King_Mustard

Several local dentists near me mainly offer Philips Zoom.

The dentist websites appear to suggest it lasts around 12 months.

Are there are forms of whitening that last longer than that, as £400-500 every 12 months or so isn't cheap.

brook2jack2

In general whitening lasts around 18 months to three years before it needs topping up. It depends a lot on your diet. 

No form of professional teeth whitening gives you better or longer lasting results, however systems that include trays for whitening at home have the advantage that when you need a top up treatment you already have the trays and only have to buy from the dentist the gels , which are normally £10 to £20 for enough for a top up. 

Systems such as zoom give no better results than tray based systems as a lot of the initial effect is due to the teeth drying out under the light.