No or Minimal Sensivity after Office Bleaching

 
Recently, tooth whitening has become one of the most desired procedures rapidly growing field of dentistry. Hydrogen peroxide is the active agent used in whitening products which releases oxygen and free radicals. These molecules attack the long-chained, dark-colored chromophore molecules and split them into smaller, less colored, and more diffusible ones. (Haywood VB, Leonard RH, Nelson CF, Brunson WD. Effectiveness, side effects and long-term status of nightguard vital bleaching. J Am Dent Assoc 1994 Sep;125(9):1219-26.) In addition to the bleaching materials that are based on various  peroxide  compounds, which may have  some detrimental  effects,  scientists  have  been  searching  for alternative approaches.  Recently, some novel synthetic hydroxyapatite materials,  which  have  similar  particle  dimensions  as  enamel, were developed. It has been assumed that these materials could react with natural hydroxyapatite on the enamel surface due to their chemical proximity to tooth structure. Additionally, it has been  also  proposed  that  teeth  could  be  whitened  with a thin layer of this material. The whitening  effect of these nano hydroxyapatite materials was evaluated in the present in vitro study. Overall, the results of the .current study manifested that all tested materials exhibited a whitening effect on enamel surface (Whitening effect and morphological evaluation of hydroxyapatite materials ALP DABANOGLU, DR MED DENT, CLAUDIA  WOOD, DR PHD, FRANKLIN  GARCÍA-GODOY, DDS, MS & KARL-HEINZ  KUNZELMANN, DR MED DENT)
In the beginning whitening, it was used high concentration H2O2 at office bleaching. As at-home tooth whitening systems used a gel of 10-25% carbamide peroxide. However, there are side effects such as damage to the hard tissue, an increase in tooth hypersensitivity.
Over the last years, lower concentration (5-10 %) hydrogen perokside and (6-10%) carbomide peroxide materials appeared. Beside the low concentration bleaching gels, the development of dental products incorporating nano-hydroxapatite to remineralise enamel and strengthen tooth structure is one of the most exciting recent  developments in dentistry. 
Nano-technology has been introduced to a variety of fields including dentistry. 
Hydroxyapatite (HA) is a major component of the hard tissue in human teeth. 
According to Prof. Martin Jörgens;
There are numerous successful applications of nHAp, including the following:
    1    protection against caries by preventing Streptococcus mutans adhering to the tooth surface;
    2     use in atraumatic restorative treatment as non-invasive caries therapy in countries with insufficient dental health care infrastructure;
    3    addition of nHAp to composite materials for longer durability of fillings;
    4    remineralisation of early carious lesions;
    5    remineralisation of erosive enamel lesions;
    6    regeneration and repair of enamel structures;
    7    sealing of dentinal tubules and formation of a protective dentine layer;
    8    formation of a protective coating against acid and subsequent reduction in hypersensitivity.
 (Tooth-whitening update: The crux of the matter by Prof. Martin Jörgens ]
Why is Bio-whitening?

The nano-hydroxyapatite is a revolutionary material with a wide  use in dentistry. 
The effect of nano hydroxyapatite is detected via electron microscope; remineralisation of the enamel surface, as well as extensive antibacterial effects on the tooth surface, protect against caries.
These potential effects of the use of nHAp described above, biowhitenig has been described as an teeth whitening procedure which low H202 percentage and with the contributions of nano hydroxyapatite.
Many manufacturers will seek to introduce similar nHAp-containing products to the market.
Nano-hydroxyapatite has remarkable remineralizing effects on initial lesions of enamel, certainly higher than traditional fluorides used until now for this purpose. Nano-hydroxyapatite is, in fact, a better source of free Ca, and this is a key element as regards the remineralization, the protection against caries and dental erosion.
(Nano-hydroxyapatite and its applications in preventive, restorative and regenerative dentistry: a review of literature:
Erlind Pepla, MD, Lait Kostantinos Besharat, MD, Gaspare Palaia, DDS, Gianluca Tenore, DDS, and Guido Migliau, DDS )
No or Minimal Sensivity

Sensivity while doing bleaching has been related to the microscopic cracks and defects on the enamel. These microcracs allow passive diffusion of the hydrogenperoxide into the pulp. 
In addition, these hairline fractures and wear facets caused from bruxism or clenching. Also, it is known that patients with dentine hypersensitivity exhibit gingival recession.
Besides, high concentration hydrogen peroxide is thermodynamically unstable.
We know no statiscal differences between high or low concentration H2O2 bleaching agents.
(Effectiveness of 6% hydrogen peroxide concentration for tooth bleaching—A double-blind, randomized clinical trial J. Martína, b, P. Vildósolaa, b, C. Bersezioa, b, A. Herrerac, J. Bortolattob, J.R.C. Saadb, O.B. Oliveira Jr.b, E. Fernández.)
Nano HAP with a size of 20 nm shares similar characteristics to the natural building blocks of enamel so that it may be used as an effective repair material.
(Repair of enamel by using hydroxyapatite nanoparticles as the building blocks Li Li,a Haihua Pan,a Jinhui Tao,a Xurong Xu,a Caiyun Mao,b Xinhua Gub and Ruikang Tang)Using a tooth whitener containing nano-hydroxyapatite crystal can effectively reduce the tooth sensitivity.
Sensitivity is a challenge for both the dental clinician and patients.
Think a system for whitening teeth and repair enamel for use in a dental office that contains the active substance hydrogen peroxide bleaching connected to the nano-hydroxyapatite. 
We could not imagine as whitening procedure, while getting whitening, micro cracks fill with natural enamel base substance nano hydroxyapatite.
Prevdent a system for whitening teeth and repair enamel for use in a dental office that contains the active substance hydrogen pero-xide bleaching connected to the nano-hydroxyapatite. 

Prevdent Re-whitening – when the two part foaming whitener is combined, it creates an active oxygen foam that  incorporates nanohydroxyapatite that is able to adhere to the tooth surface and microcracs repair enamel and deliver 6% hydrogen peroxide to the teeth that results in a whiter, brighter smile
Enamel repair – the repairing serum delivers concentrated nano-hydroxyapatite that remineralises and repairs the tooth surface leaving the patient with a healthy white smile with no sensitivity or damage to the enamel.
Conclusion

Low concentration hydrogen peroxide containing 20nm particle size nano hydroxyapatite potential to remineralise in enamel.
Additionally, nanohydroxyapatite have been promoting remineralization with regular daily usage.

Dr. Betul Yurteri