Minimum Sensitivity after External Bleaching

7 Apr 2016 - 26522

Patients often come to the dental office asking to have their smiles improved as they feel that a “beautiful smile” is something that would make their social lives better. However, potential patients are unaware of treatment options, so it is the dentist’s responsibility to advise the most conservative, desirable treatment. When patients complain about, to use their words, “ugly teeth” the dentist must determine whether the term ugly is the result of color or shape of the dentition. Therefore the following questions are appropriate: (1) Are you comfortable with the shape of your teeth and (2) do you approve of the color of your teeth?
If the answer to question 1 is affirmative and color is the main concern, we have many options to provide our patient with. It should always be the less invasive choice to be the first submitted to the patient. External bleaching could be sometimes the best option; however the patient should understand that this procedure is a temporary solution and, to maintain the results, he will have to follow some indications – minimum smoking, less stain drinking.
Bleaching-induced tooth sensitivity has been associated with microscopic surface defects and sub-surface pores in the enamel, with consequent reduction in enamel micro-hardness: thus because of the low pH of the in-office bleaching gels available on the market. It has been theorised that these defects allow rapid diffusion of the whitening agent into the pulp, resulting in inflammatory reaction and bleaching-induced tooth sensitivity. The association between low pH bleaching gels and the risk of tooth sensitivity is still unclear.
However, theoretically, a product that encourages repair of these microscopic defects can reduce, or at least minimize, tooth sensitivity by diminishing diffusion of hydrogen peroxide into the pulp. Consequently, manufacturers added different compounds such as fluoride, potassium nitrate, and different calcium phosphate salts to bleaching products. Fluoride and potassium nitrate have been frequently used to manage tooth sensitivity with clinical success.
White Dental Beauty is a market leader in tooth whitening materials. Its professional range of high quality tooth whitening gels includes 6% hydrogen peroxide and 5% 10% &16% carbamideperoxide with NOVON, providing the clinician with great versatility and clinical freedom to whiten your patients teeth from as little as 30 minutes a day.
White Dental Beauty is powered by NOVON a new chemical technology which uses an Intelligent pH acceleration for a maximum whitening effect. Teeth can be whitened quickly and effectively in a reduced time frame for greater patient compliance.
NOVON is a new, patented whitening compound that comprises hydrogen peroxide, urea and sodium tripolyphosphate (Reference to Technical Image; “Postulated Structure of NOVON”) and is the active ingredient in a new generation of tooth whitening gels.
NOVON has a unique inherent feature in that, on application, it produces a “pH jump” into the alkaline pH range. This “pH jump” enhances the release of perhydroxyl ions for a faster whitening effect. (Reference to Technical Images; “Generation of the Perhydroxyl Ion” & “Diagram to Explain the Whitening Action of Perhydroxyl Ions”).
NOVON – containing gels can therefore produce a similar whitening effect within a shorter time-frame, in comparison to whitening using a regular gel. Alternatively, within the same time frame, a similar level of whitening can be achieved with a lower inclusion level of NOVON® (Hyland et al., 2014). This should be an advantage to patients with sensitive teeth.
NOVON has 4 options for home bleaching:
6% HYDROGEN PEROXIDE – from as little as 30 minutes a day
16% CARBAMIDE PEROXIDE – from as little as 60 minutes a day
10% CARBAMIDE PEROXIDE – 2-4 hours ovenight
5% MILD CARBAMIDE PEROXIDE – 2 hours a day

In the following case we have chosen the 6% HYDROGEN PEROXIDE for 30 minutes a day during 14 days.
A bleaching custom tray was made and the patient was instructed on how to use the 6% HYDROGEN PEROXIDE bleaching gel.
The patient was asked to keep a journal, during and after the bleaching procedure, reporting the grade of tooth sensitivity, from 0 to 10 (where 0 is the absence of sensitivity and 10 is the high sensitivity).
In the first session we took a picture with the VITA shade to establish the initial situation.

Fig. 1

Img. 1 – Each picture was calibrated at the level of the gingiva using Photoshop CS with the CIE Lab color measurement. From this data we extract the L data, representing the value and we calibrated the other pictures using levels to get, in the end, all pictures at the same exposure.

Fig. 2

Img. 2 – The initial smile picture situation.

Fig. 3

Img. 3 – The initial intaoral initial situation.

Fig. 4

Img. 4 – Picture with VITA shade color tray. Taking this picture is a very important step both for dentist and the patient. The home bleaching procedure provides a progressive change of the color. Patients tend to look in the mirror many times a day to analyze the effect, so that it could be unobservable for them. By comparing the initial and final situation pictures we show our patients the color change.

Fig. 5

Img. 5 – 8 days progress using the HP 6% for 30 min/day. Smile view.

Fig. 6

Img. 6 – 8 days progress using the HP 6% for 30 min/day. Intra-oral view.

Fig. 7

Img. 7 – 8 days progress using the HP 6% for 30 min/day. VITA comparison.

Fig. 8

Img. 8 – 14 days progress using the HP 6% for 30 min/day. Smile view.

Fig. 9

Img. 9 – 14 days progress using the HP 6% for 30 min/day. Intra-oral view.

Fig. 10

Img. 10 – 14 days progress using the HP 6% for 30 min/day. VITA comparison.