The Elements Leading to Consistent Whitening Results

The excellent results that we have seen with the BriteSmile whitening procedure occur because of the proprietary combination of the intensity and color of the light source and the strength and composition of the chemistry.

The BriteSmile procedure has been independently tested under controlled clinical conditions that are easy to replicate in the typical dental office setting. These conditions ensure that both the intensity of the light source is correct and that the strength of the gel is preserved throughout the procedure.

While there are other factors listed below which could play a role in a poor result, these two are the most important. Both factors are easily controlled, and thorough training of the staff can create the correct conditions for a good result.

1) Chemistry

This is the simplest factor, because it involves quality control during manufacturing. Each batch of BriteSmile Gel is tested for a variety of properties, including hydrogen peroxide concentration, pH, viscosity, and stability to heat shock (a good predictor of shelf life). Whenever we receive a complaint about poor results, the manufacturer looks into the manufacturing process for the particular batch cited to see if any changes occurred, and to retest the retained samples (which are kept for a minimum of two years from the date of manufacture).  To date, there has never been a retest that indicated any out-of-specification variable that would account for a reduction in tooth whitening efficacy. Since opening the first Center in Walnut Creek the content and manufacturing procedure of the gel has not changed in any way that would make a difference with the results.

2) Intensity of the light source

The intensity of the light source is critical to the procedure.  For the BS3000 systems we work at a range of 120-130mW/cm2.  Below 100mW/cm2 a fairly sharp drop in efficacy occurs. Two factors can influence the intensity of the light source:  position of the front end with respect to the teeth and weakening of the lamps with time.  The fiber optic positioner is designed to just touch the small dimple in the plastic housing at the output end of the light, putting the light at exactly 1.75 inches from the teeth.  If it is one-half to one inch further away, then the intensity of the light on the teeth goes down below the 100mW/cm2 threshold and the whitening effect can be lowered significantly.  Similarly, the calibration procedure is designed to mitigate the effects of weakening of the lamps with time.  Calibration should occur every one to two weeks in order to insure the intensity is correct.  Systems that cannot be correctly calibrated should be replaced or significantly less effective whitening result may be expected to occur.  Additionally, not setting the front end at the correct angle could result in lowered intensity on portions of the arch. The front end should be directly in front of the patientŐs front teeth with the fiber optic positioner looking straight down the middle of the front end.

LOWERED INTENSITY CAUSED BY EITHER TOO LARGE A DISTANCE FROM THE TEETH, A SKEWED ANGLE OR A POORLY CALIBRATED LAMP COULD CLEARLY BE A REASON FOR PERIODICALLY POOR RESULTS

3) Gel application technique

We have seen several problems with gel application technique.  The most common problem is accidentally mixing the whitening gel with the Masking Cream during the procedure. This effectively blocks the action of the gel, and a very poor result will occur. Secondly, poor control of the saliva during the procedure can dilute the gel sufficiently to create a poor result. Finally, failing to aspirate and replace the gel every twenty minutes will also create a poor result because of drying of the gel and subsequent weakening of the chemistry.

4) Genetics and intrinsic color

Each patient responds differently to a bleaching procedure, and this response is unpredictable except with respect to large groups. The factors of intrinsic tooth color and genetics will strongly affect the exact result that any given patient experiences. The fact that both genetics and tooth color may be consistent within local populations could reasonably be expected to play a role in why we occasionally see groups of poor results at specific locations. The more patients we treat (i.e., the larger the population) the more we could be expected to see this effect. What this means is that just as we can get a long run of heads by flipping a coin, we can get a run of bad results just from the statistical probability of having many patients of the same intrinsic tooth color and genetic type come in the door in the same week.

5) Poor observations

This factor means that the data being used to determine that „we arenŐt getting the great results that we used to get“ are primarily anecdotal, not scientifically based. What often happens is that the observer (dentist, DA, DH) remembers the most recent result and can also point to another similar example in the recent past and then puts these two results together to draw the negative conclusion, without actually putting together data from a consistent group of patients and looking at it objectively. This is particularly true if the population of patients has an average starting shade of less than A3, because our average of 8-9 shades pertains only to patients who can benefit from this large amount of change. Without a sufficient amount of consistent data, it is not possible to conclude that „the process is not working“.

6) Shade guide

Finally, we have found that some dental offices do not order the VITA shade guide according to the manufacturerŐs instructions for making value (i.e., shade) measurements. This is often the case when the guide is used for both cosmetic and restorative work where the dentist is trying to accurately match colors for restorations. Some dentists believe that the shade guide should be only used when the tabs are grouped by color (AŐs together, BŐs together, etc.). If this is the case, then that office will not get accurate results, and they will not match our clinically proven results.

The shade guide must be ordered according to the manufacturerŐs instructions for its use as a shade measurement as specified to be in the following order:

B1 A1 B2 D2 A2 C1 C2 D4 A3 D3 B3 A3.5 B4 C3 A4 C4

While there are arguments within the industry that this ordering is not a very accurate measurement of brightness (value), it does represent the current standard by which all reputable independent clinical studies are conducted and compared. Dental offices often accidentally mix up this order during their busy day, resulting in inaccurate shade numbers, so periodically checking the shade guide is a way to avoid this problem.