The possibility is aesthetically restore a tooth is not vital, means that conservative methods, using chemical composites could leave untouched the remaining tooth substance, and it returns to full the three components of color, has been pursued since 1850 when Dwindle, recommended for bleaching devitalized teeth of the use of calcium chloride, used in the bleaching of textiles and pulp.
Following were tested various substances such as oxalic acid, used in bleaching fiber plant in tanning and bleaching of skins, based compound chlorine etc. Even the use of hydrogen peroxide at 30% used for bleaching teeth is ancient in his first description of use. It was to put a pasta oxidant, formed from a mixture of sodium perforate and distilled water in the pulp chamber that was sealed temporarily for a few days, with temporary cement. The mixture could be replaced after 3-7 days, repeating the process until reaching an aesthetically acceptable result. This same change was later reconsidered by Spasser in 1961, applying essentially the same concepts and the same mixture.
Nutting & Poe added to sodium perforate hydrogen peroxide to 30 – 35%, the two substances act synergistically, and both releasing oxygen, were to make the bleaching more rapidly and effectively.
Over the years various authors using this type of technology have changed the association between the components (perforate mixed with water or hydrogen peroxide), the percentage of peroxide idrogenoimpiegato, the type of PBS used.
We will see later how these various combinations, can affect both the clinical results that the side effects.