Dentin Hypersensitivity: Consensus-Based Recommendations for the Diagnosis & Management of Dentin Hypersensitivity
Considerations for Managing Bleaching Sensitivity
Tooth sensitivity is the single most significant
deterrent to bleaching, and must be understood to be able to manage the
treatment of patients. All forms of vital tooth bleaching are associated
with some level of sensitivity.1-6 Hence, the dental office and the patient must be
prepared for the possibility of sensitivity during bleaching treatment.
PREVALENCE AND CAUSE
The three major classes of bleaching—in-office,
tray, and over-the-counter (OTC)—all demonstrate some prevalence of
sensitivity. Typical bleaching ingredients are either hydrogen peroxide or carbamide peroxide. For comparison, a 10% carbamide peroxide product is approximately 3.5% hydrogen
peroxide. Generally, the higher the concentration of the peroxide, the
greater the chance of sensitivity.7 In-office bleaching uses the highest concentration of
peroxide (15% to 35% hydrogen peroxide), and has a range of sensitivity from 10% to 90%, with some sensitivity being so severe as
to require analgesics posttreatment.8-10 Typically,
multiple in-office visits are required for
maximum whitening,11 and those visits should be
spaced at least 1 week apart to allow for reduction
of sensitivity caused by treatment.12 It is also recommended to
pre-medicate patients with non-steroid anti-inflammatory drugs to reduce the incidence
The second highest concentration
of peroxide is found in the OTC products.
typically range from 6% to 15% hydrogen
peroxide. Although they have a shorter treatment time due to the limited efficacy of
hydrogen peroxide (30 to 60 minutes), they still generate tooth sensitivity
as well as gingival irritation. Even shorter treatment times of OTC strips
with higher concentrations have exhibited greater sensitivity than lower
concentrations with longer treatment times.13
The classic tray bleaching treatment involves 10%
carbamide peroxide or 3.5% hydrogen peroxide. Incidences of 25% to 75% are
reported,14,15 although differences in study design influence data in all
treatment options. Generally, sensitivity occurs in the first 2 weeks of
treatment, often in the first few days.16 The more recent addition of potassium nitrate to bleaching
materials has reduced, but not eliminated, sensitivity. It is important to
note that the presence of sensitivity is the most probable cause for
persons discontinuing bleaching, with one report of 14% termination of
bleaching due to sensitivity.17
A recent report on double-blinded, placebo-controlled
clinical trials has provided evidence that the addition of low levels of potassium nitrate and/or potassium nitrate and
fluoride significantly reduce postoperative
sensitivity relative to products that do not contain either agent.3,5
Whereas all of the typical causes of dentin
hypersensitivity generally involve the
hydrodynamic theory of fluid flow, the sensitivity associated with
bleaching seems to have a different origin. In bleaching situations, the
teeth may be in excellent condition, with no cracks, exposed dentin, or deep restorations,
but after a few days of bleaching, the tooth may experience severe sensitivity. This seems to
be related to the easy passage of hydrogen peroxide and urea through the
intact enamel, through the dentin in the interstitial spaces into the pulp within 5 to 15 minutes.18 In effect, the tooth
is a semipermeable membrane that is quite
open to certain-sized molecules. Once it is understood how easily the
peroxide penetrates the tooth, the resultant pulpal response of sensitivity
may be considered a reversible pulpitis. Tooth sensitivity is the main side
effect of bleaching, and may be caused primarily by the peroxide
penetration to the pulp, and secondarily by the mechanical pressure of an
improperly fitting tray or occlusion on the tray. The other side effect
recorded is gingival irritation, which may be related to an improperly
fitted tray, occlusion on the tray, or chemical irritation from higher
concentrations of hydrogen or carbamide peroxide.
Because tooth sensitivity mainly depends on inherent
patient sensitivity, frequency of application,
and concentration of the material, a history of sensitivity should be
determined during the examination.14,19 Patients generally will report or should be asked if their
teeth are sensitive to cold. Additionally, existing sensitivity can be
determined from the preoperative exam by simple methods of explorer contact
with areas on the teeth, or air blown on the teeth. Patients can be
counseled in the frequency of application and the appropriate concentration
of bleaching agent, with instructions that applications more than once a
day or higher concentrations of bleaching agent increase the likelihood of
sensitivity.3,4,20-22 All other delineators, such as pulp size, exposed
dentin, cracks, gingival recession, caries, sex or age of the patient, or
other physical characteristics are not predictive of who would have
Most reports of sensitivity occur within the first 2
weeks, regardless of how long the patient may treat their teeth. Often,
these reports are a single day of sensitivity, followed by no problems the
next day. The tooth’s response to bleaching is very individualistic,
and can only be determined by beginning treatment. However, the history of
sensitive teeth by the patient, as well as their response during
examination to explorer touch or air, can be a reasonable predictor.
Because bleaching tends to produce some tooth
sensitivity under ordinary circumstances, patients with pre-existing tooth
sensitivity must be cautioned that increased sensitivity, albeit
transitory, may occur, and that management of the sensitivity may require a
longer time span for bleaching as a result of the additional time to treat
Other contributors to sensitivity include rigid tray
materials, the base vehicle composition and viscosity, flavoring agents, or
patient habits such as clenching or bruxism. The short-term pulpal response
varies from patient to patient and even from tooth to tooth. Although
penetration of peroxide through the tooth to the pulp can produce
sensitivity, the pulp remains healthy and the sensitivity is completely
reversible when treatment is terminated. No long-term sequelae remain after the sensitivity has abated.23-25 Research also has shown that patients have tooth sensitivity
even when using a non-bleaching agent in a tray, or just wearing a tray
alone. Hence, it is not possible to have all patients be sensitivity-free
because of the mechanical forces of materials and occlusion, and some plans
must be made to address potential problems.
Most of the earlier treatments for sensitivity
involved tray bleaching, as the ease of use of this system and universal
popularity made it the most commonly used system for tooth bleaching.26,27 The passive
approach for treating sensitivity was first used. This involved a reduction
in wear time, or in frequency of application. Sensitivity treatment could
also involve temporary interruption of the bleaching treatment. After the
interruption, treatment can often be resumed without any further
sensitivity. Cessation of treatment results in no lingering sensitivity.
Although the passive approach has some success, patients and dentists prefer to have a more active approach. The
active approach involves the use of either fluoride, potassium nitrate, or
both in combination. Traditionally, fluoride has been used as a
method of reducing sensitivity. The primary mechanism
for action is to occlude dentinal tubules or increase the hardness of enamel,
which impedes the
flow of materials to the pulp. However, the peroxide molecule is so small
that it can travel in the interstitial
spaces between the dentinal tubules. Hence,
fluoride has not been particularly beneficial in treating bleaching
Potassium Nitrate Use in Bleaching
Potassium nitrate has a completely different mechanism
of action than fluoride. Potassium nitrate penetrates the enamel and dentin
to travel to the pulp and creates a calming effect
on the nerve by affecting the transmission of nerve impulses. After the nerve depolarizes in the pain stimulus-response, it cannot re-polarize, so the excitability of the
nerve is reduced. Potassium nitrate almost
has an “anesthetic-like effect” on the nerve.
One study demonstrated that applying potassium nitrate
for 10 to 30 minutes in a bleaching tray could be successful in reducing
sensitivity in more than 90% of the patients, and allow them to complete
the bleaching procedure successfully.28 This technique was originally used by Jerome to treat tooth
sensitivity after periodontal surgery in non-bleaching patients.29 He placed
desensitizing toothpaste into soft trays that covered the now-exposed root surfaces of the
teeth, and achieved good results. For patients
with chronic sensitivity unrelated to
bleaching, the toothpaste gives them an OTC product that they can use whenever they need
it with tray application, even before a
prophylaxis. This approach was extended by Haywood to include
patients experiencing sensitivity during bleaching.28 Tray application
could be used either before or after the bleaching treatment (Figure 1 View Figure). Because the pain can occur remotely from the bleaching treatment,
the potassium nitrate could be used as needed during the day
or night. In severe situations, the potassium
nitrate could be substituted for the
bleaching material on alternating nights of wear.
The more readily available source of 5% potassium
nitrate in the United States is desensitizing
toothpastes that contain 5%
potassium nitrate. Five percent is the maximum amount of potassium nitrate
approved by the US Food and Drug Administration, and is the primary
ingredient for sensitivity treatment allowed in OTC toothpaste. Based on
the tray application study, desensitizing toothpaste can be placed in the
tray for 10 to 30 minutes whenever sensitivity occurs. The only caution
with toothpaste application is that some patients may experience a gingival
reaction to the foaming ingredient sodium lauryl sulfate. This reaction is
not caused by the potassium nitrate. The reaction generally produces a
tissue burn or reddening of the gingiva. If this irritation occurs with one
brand or flavor of toothpaste, the clinician may have to experiment with
various OTC formulations for certain patients. Initially there was only one
toothpaste available which had potassium nitrate, but not sodium laural
sulfate, and that was the original “Pink packaged” Sensodyne.
More recently, the advent of “Pronamel Sensodyne” has provided
a new option for a non-sodium laural sulfate, potassium-nitrate containing
toothpaste to be used in brushing or in the tray for treatment of
If suitable toothpaste cannot be found for the patient, then the clinician should use the
professionally available products containing 3% to 5% potassium nitrate and
Several companies provide 3% to 5% potassium nitrate
in a syringe for application in the bleaching tray as needed. The syringe
materials, which must be purchased from the companies, may be more
appropriate for episodic sensitivity associated with the bleaching itself
where the toothpaste was not acceptable because of the gingival response.
There are also disposable trays containing
potassium nitrate which may be helpful, especially if there is no bleaching tray available for in-office
techniques being used alone.
Once research determined that potassium nitrate in the
tray was successful, the next step was to incorporate this material in the
bleaching material rather than require a separate application. First
attempts were not too chemically successful, but now most manufacturers
have their bleaching product containing both fluoride and potassium
nitrate. Examples of this would be Opalescence PF (Ultradent Products, Inc,
South Jordan, UT), NiteWhite® Excel and NiteWhite®
ACP (Discus Dental, Culver City, CA), Contrastpm® (Spectrum Dental, Corpus Christi, TX) , GC TiON (GC
America), and Opalescence® Treswhite Supreme (Ultradent
Products). Early concerns were that either the fluoride or the potassium
nitrate would interfere with the bleaching, but one study has indicated
that bleaching efficacy is not reduced.30 Certainly, if there is any reduction in efficacy or
increase in time of treatment, it is minor, and much better than
termination of bleaching resulting from unmanageable sensitivity.31 Having the
potassium nitrate in the material could also minimize the effects of
mechanical irritation from an improperly fitting tray or occlusion causing
movement of the tray and resultant tooth sensitivity.5
Pre-Brushing with Potassium Nitrate for Sensitivity
Even though tray application of potassium nitrate was
very effective, and the incorporation of potassium nitrate into the
bleaching material has helped, these advances do not totally eliminate
sensitivity. Relief from sensitivity requires brushing with potassium
nitrate for approximately 2 weeks to be effective.32 A recent study33 compared
patients who pre-brushed with the toothpaste containing potassium nitrate
(Sensodyne) for 2 weeks before initiating bleaching to another group that
used conventional fluoride-containing toothpaste. The group that
pre-brushed with the potassium nitrate-containing toothpaste had less
sensitivity overall, less sensitivity in the first 3 days, and more
sensitivity-free days before a first occurrence. Results of patient surveys
showed that the switch to a potassium nitrate-containing toothpaste was
easy and well-accepted.
Bleaching sensitivity may result from a combination of
the patient’s pre-existing tooth and gingival conditions, the
chemical nature of the peroxide, and the mechanical nature of the tray. The
dentist should determine if the patient has pre-existing sensitive teeth
that require a protocol to minimize sensitivity during bleaching. If the
patient has no pre-existing sensitivity, a proactive protocol should be
developed to address sensitivity should it occur. Figure 2 (View Figure) and Figure 3 (View Figure)
offer this information in two treatment options, one for patients with a
history of sensitivity, and one for patients with
no pre-existing sensitivity. They also explain the options for passive or active treatment of sensitivity that
occurs once the bleaching process is initiated.
Treatment of bleaching sensitivity involves many
possible options (Figure 4 View Figure). Prebrushing with a potassium
nitrate-containing toothpaste can reduce or avoid sensitivity from
bleaching. Tray application of potassium nitrate can be an effective
episodic treatment for sensitivity. Other treatment time variations, use of
different concentrations of material, and varying tray designs can all be
part of a sensitivity management program. It is far better to try to avoid
or minimize the sensitivity with the above steps than to treat sensitivity
after it occurs. Even with all these options for sensitivity avoidance and
treatment, there are still some patients who cannot manage their
sensitivity and elect to terminate bleaching. Sensitivity seems to be a
multi-factorial event which cannot be entirely controlled in every patient.
However, the majority of patients, after a proper dental examination,
history, and radiographs, can find an appropriate method with adjustment of
treatment time and material, brushing with a desensitizing toothpaste
containing potassium nitrate, or tray application of potassium nitrate, to
minimize any sensitivity they may encounter, and proceed to a successful
completion of the bleaching process.
1. Auschill TM, Hellwig
E, Schmidate S, et al. Efficacy, side-effects and
patients’ acceptance of different bleaching techniques (OTC, in-office, at-home). Oper Dent.
2. Leonard RH, Bentley C, Eagle JC, et al. Nightguard
vital bleaching: A long-term study of efficacy, shade retention, side
effects, and patients’ perceptions. J Esthet
Restor Dent. 2001;13(6):357-369.
3. Browning WD, Blalock JS, Frazier KB, et al.
Duration and timing of sensitivity related to bleaching. J Esthet Restor
4. Browning WD, Swift EJ. Critical appraisal:
Comparison of the effectiveness and safety of carbamide peroxide whitening
agents at different concentrations. J Esthet Restor Dent. 2007;19(5):
5. Browning WD, Chan DC, Myers ML, et al. Comparison
of traditional and low sensitivity whiteners. Oper Dent. 2008;33(4):
6. Leonard RH, Smith LR, Garland GE, et al.
Evaluation of side effects and patients’ perceptions during tooth
bleaching. Esthet Restor Dent. 2007;19(6):355-366.
7. Browning WD, Swift EJ. Critical Appraisal:
Comparison of the effectiveness and safety of carbamide peroxide
whitening agents at different concentrations. J Esthet Restor Dent.
8. Paparthanasiou A, Bardwell D, Kugel G. A
clinical study evaluating a new chairside and take-home whitening ssystem. Compendium. 2001;22(4):289-298.
9. Lu AC, Margiotta A, Nathoo SA. In-office tooth
whitening: current procedures. Compendium. 2001;22(9):798-805.
10. Kugel G, Papathasiou A, Williams AJ, et al.
Clinical evaluation of chemical and light-activated tooth whitening
systems. Compendium. 2006;27(1):54-62.
11. Gottardi MS, Brackett MG, Haywood VB.
Number of in-office light-activated bleaching treatments needed to
achieve patient satisfaction. Quintessence Int. 2006;37(2):115-120.
12. Goldstein CE,
Goldstein RE, Feinman RA, Garber DA. Bleaching vital teeth: state of the art. Quintessence Int. 1989;20(10);729-737.
13. Gerlach RW, Sagel PA.Vital bleaching with a thin
peroxide gel: The safety and efficacy of a professional-strength hydrogen
peroxide whitening strip. J Am Dent Assoc. 2004;135(1):98-100.
14. Haywood VB, Leonard R, Nelson CF, et al.
Effectiveness, side effects and long-term status of nightguard vital
bleaching. J Am Dent Assoc. 1994;125(9):1219-1226.
15. Haywood VB. Dentine hypersensitivity: bleaching
and restorative considerations for successful management. Int Dent J. 2002:
52(5 suppl 1):376-384
16. Jorgensen MG, Carroll WB. Incidence of tooth
sensitivity after home whitening treatment. J Am Dent Assoc. 2002;133(8):
17. Schulte JR, Morrissette D B, Gasior E J, et al.
The effects of bleaching application time on the dental pulp. J Am Dent
18. Cooper JS, Bokmeyer TJ, Bowles WH. Penetration of
the pulp chamber by carbamide peroxide bleaching agents. J Endod. 1992;18:
19. Leonard RH, Haywood VB, Phillips C. Risk factors
for developing tooth sensitivity and gingival irritation associated with
nightguard vital bleaching. Quintessence Int. 1997;28:527-534.
20. Kihn P, Barnes DM, Romberg E, Peterson K. A
clinical evaluation of 10 percent VS 15 percent carbamide peroxide
tooth-whitening agent. J Am Dent Assoc. 2000;131:1478-1484.
21. Krause F, Soren J, Braun A. Subjective
intensities of pain and contentment with treatment outcomes during tray
bleaching of vital teeth employing different carbamide peroxide
concentrations. Quintessence Int. 2008;39:203-209.
22. Matis BA, Mousa HN, Cochran MA, Eckert GJ.
Clinical evaluation of bleaching agents of different concentrations. Quintessence
23. Pohjola RM, Browning
WD, Hackman ST, et al. Sensitivity and tooth whitening agents. J Esthet Restor Dent. 2002;14:
24. Ritter AV, Leonard RH, St Georges AJ, et al.
Safety and stability of nightguard vital bleaching: 9 to 12 years
post-treatment. J Esthet Restor Dent. 2002;14(5):275-285.
25. Swift EJ. Critical appraisal: At-home bleaching:
pulpal effects and tooth sensitivity Issues. Part 1. J Esthet Restor Dent. 2006;18(4):225-228.
26. Haywood VB. Dentine hypersensitivity: bleaching
and restorative considerations for successful management. Int Dent J. 2002,52(5 Supp1):376-384.
27. Haywood VB. Treating sensitivity during tooth
whitening. Compend Cont Educ Dent. 2006;26(9):11-20.
28. Haywood VB, Caughman WF, Frazier KB, et al. Tray
delivery of potassium nitrate fluoride to reduce bleaching sensitivity. Quintessence
29. Jerome CE. Acute care for unusual cased of
dentinal hypersensitivity. Quintessence Int. 1995;26:715-716.
30. Tam L. Effect of potassium nitrate and fluoride on
carbamide peroxide bleaching. Quintessence Int. 2001;32:766.
31. Leonard RH, Smith LR,
Garland GE, Caplan DJ. Densensitizing agent
efficacy during whitening in an at-risk population. J Esthet Restor Dent. 2004;16:49-56.
32. Silverman G, Berman E, Hanna CB, et al. Assessing
the efficacy of three dentifrices in the treatment of dentinal
hypersensitivity. J Am Dent Assoc. 1996;127:191-201.
33. Haywood VB, Cordero F, Wright K, et al. Brushing
with potassium nitrate dentifrice to reduce bleaching sensitivity. J Clin
|Figure 1 Tray application of a potassium nitrate-containing desensitizing
material is a very effective approach to treatment of sensitivity.
|Figure 2 Bleaching Sensitivity Treatment: Stage 1 Prevention options in patients with existing sensitive teeth.
||Figure 3 Bleaching Sensitivity Treatment: Stage 2 Treatment options for patients who experience sensitive teeth during bleaching.
|Figure 4 The three options for avoidance or treatment of -
bleaching sensitivity involve the application of potassium
nitrate products either in the bleaching tray or topically.