THE HOME WHITENING TECHNIQUE

Linda Greenwall

INTRODUCTION

Home whitening is a simple technique whereby, after an initial consultation with the dentist, a mouthguard or tray is made for the patient to whiten the teeth at home. The patient is given the tooth whitening materials (normally 10% carbamide peroxide) to take home, together with a detailed whitening protocol. The patient applies the whitening material to the tray. The tray with the material is worn for several hours during the day or at night depending on the patient’s schedule, while the teeth lighten. It is a predictable technique and has a success rate of 98% for non–tetracycline-stained teeth and 86% for tetracycline-stained teeth (Leonard 2000). The introduction of Nightguard Vital Bleaching in 1989 revolutionized whitening technology; the technique was simple, and dentists could provide treatment easily for patients. The overall cost was reduced and the technique has become extremely popular, enabling millions of people around the world to benefit from whitening treatment. It is the aim of this chapter to describe the home whitening technique and protocol in detail, so that successful whitening treatments can be achieved.

TERMINOLOGY

Many names have been used for home whitening. The original term used was “Nightguard Vital Bleaching,” because patients whitened the teeth at night while they slept with the tray in their mouths (Haywood and Heymann 1989). “Home whitening,” some may argue, does not distinguish the procedure from that performed by patients who buy the over-the-counter kits and self-prescribe the whitening treatments. However, the term will be used for simplicity. Names associated with home whitening include the following:

•  Nightguard Vital Bleaching.

•  Matrix bleaching.

•  Dentist-assisted or dentist-prescribed home-applied whitening.

•  Dentist-supervised at-home whitening.

•  At-home whitening.

THE PROS AND CONS OF HOME WHITENING

Advantages

•  It is simple and fast for patients to use (Christensen 1997).

•  It is simple for dentists to monitor without extended clinical time.

•  It is cost-effective (Greenwall 1992).

•  The laboratory fees for making the whitening tray are not high.

•  It is not usually a painful procedure.

•  Patients can whiten their teeth at their convenience, according to their personal schedule.

•  Patients can see the results relatively quickly.

•  Patients are normally delighted with the result!

DISADVANTAGES

•  Patients need to participate actively in their treatment (Miller 1999).

•  The color change is dependent on the amount of time that the trays are worn. If patients do not wear the whitening agent in the trays for the specified amount of time, changes in tooth lightening will be slow.

•  Some patients cannot be bothered with applying the whitening agent in the trays every day. The dropout rate for home whitening may be as much as 50% according to anecdotal feedback (Miller 1999). Some patients may need further motivation and encouragement to continue whitening through use of an office-assisted program or power whitening.

•  The system may be open to abuse by use of excessive amounts of whitening agent for too many hours per day (Garber 1997).

•  It is difficult for patients who gag easily to tolerate the whitening trays in the mouth.

INDICATIONS FOR USE

Home whitening (Greenwall 1999b) can be used for the following:

•  Mild generalized staining (combination of factors [Greenwall 1992]; see Figures 5.10A–G).

•  Age-yellowing discoloration (see Figures 5.24A–C).

•  Mild tetracycline staining.

•  Very mild fluorosis (brown or white) (see Figures 5.10A–G).

•  Acquired superficial staining.

•  Stains from smoking tobacco (see Figure 5.20A–C).

•  Absorptive and penetration stains (tea and coffee; see Figure 5.22A).

•  Color change related to pulpal trauma or necrosis.

•  Patients who desire a minimal amount of dental treatment to achieve a color shift (see Figures 5.19A–G).

•  Young patients with an inherited gray or yellow hue to the teeth who are unhappy about this (see Figures 5.18A and 5.18B).

CONTRAINDICATIONS TO USE

There are many contraindications to home whitening (Greenwall 1999b). Home whitening agents should not be used in the following situations:

•  Severe tetracycline staining.

•  Severe pitting hypoplasia.

•  Severe fluorosis stain.

•  Discolorations in the adolescent patient with large pulps (Haywood 1995).

•  Patients with unrealistic expectations about the anticipated esthetic result (Wise 1995).

•  Teeth with inadequate or defective existing restorations (these should be temporarily blocked before whitening).

•  Teeth with tooth surface loss from attrition, abrasion, and severe erosion.

•  Teeth with insufficient enamel to respond to whitening (i.e., pitted teeth, defective enamel); however, this might be acceptable because it is the dentin that is important for determining the shade color (Bentley et al. 1999).

•  Teeth with deep and surface cracks and fracture lines (see Figure 5.22A).

•  Teeth with large anterior restorations that have existing sensitivity.

•  Teeth with pathology such as a periapical radiolucency.

•  Teeth that are fractured or misaligned may be better treated with other treatments such as porcelain veneers or orthodontics. Further treatment may be necessary.

•  Patients who demonstrate a lack of compliance through inability or unwillingness to wear appliance for the required time (Garber et al. 1991).

•  Patients who are pregnant or lactating—at this stage, the effect of the whitening agent on development of the fetus is unknown (Garber et al. 1991).

•  Patients who smoke—patients cannot smoke and whiten their teeth at the same time because this may enhance the carcinogenic effect of the smoking (see Figure 5.20).

•  Teeth exhibiting extreme sensitivity to heat, cold, touch, and sweetness.

Although the last point is not strictly a contraindication, whitening teeth can sometimes cause transient sensitivity. It may be better to treat the sensitivity first with fluoride applications, a bonding agent, or a bonded restoration before whitening. It may also be necessary to protect any erosion or abrasion area (Greenwall 1999a).

ALTERNATIVES

The alternatives to home whitening may involve the following:

•  In-office whitening, such as power or laser whitening.

•  Porcelain veneers (see Figures 5.17A and 5.17B).

•  Composite veneers.

•  Composite bonding.

•  Crowns: all-porcelain crowns or porcelain-bonded-to-metal crowns.

•  Further restorations.

•  Combinations of treatments.

Most of these options are more invasive and destructive than home whitening. The preparation for crowns (particularly the new all-porcelain crowns) requires removal of at least 1 to 1.5 mm of tooth tissue (even 2 mm).

THE PROTOCOL

Once a patient has expressed an interest in having his or her teeth lightened, several aspects need to be discussed, before the first whitening visit. After assessing the patient’s medical history, it may be useful to ask the patient to complete a tooth discoloration questionnaire to ascertain which foods or drinks are causing the staining (see Figure 5.1). Patients should reduce the intake of foods that are causing the staining of the teeth before whitening treatments are begun. Patients should be warned of the possibility of experiencing caffeine withdrawal symptoms if they stop drinking coffee or tea immediately.

The dentist needs to assess whether the patient is taking any medication that can affect whitening treatment, such as antihistamines, which make the mouth dry (see Chapter 4). Any allergies to components of the whitening product, such as glycerin, flavoring agents, or preservatives, or the whitening tray components need to be checked (see Figure 5.3). Patients who smoke should be counseled to stop smoking before any whitening treatments are begun. Patients are advised that they should not whiten their teeth if they are smoking.

INITIAL CONSULTATION

The initial discussion with the patient should address the following:

•  The advantages and disadvantages of tooth whitening.

•  Alternatives to whitening treatments.

•  Any side effects that may be experienced (such as sensitivity, gingival irritation; see Figure 5.15).

•  The risks and benefits of the procedures; the patient’s informed consent should be obtained (see Figure 5.15).

•  All treatment options, including the possibility that more than one whitening treatment may need to be undertaken.

•  The duration of treatment.

•  Further esthetic treatment that may be needed.

•  Further dental treatment such as replacement of stained and leaking composites.

It is essential to set whitening goals before treatment. Use the appropriate procedures for diagnosis, treatment planning, and evaluation of the teeth, which were discussed in Chapter 4.

CLINICAL EXAMINATION OF ALL TEETH

A comprehensive examination should be performed to assess the oral environment (Fischer 2000b), soft tissues, mucosae, teeth, gingivae, and oral health status of the patient. Check the integrity of the existing restorations. Check recent radiographs for dental disease and periapical radiolucencies (Haywood 1997b). The size and vitality of the pulps of the teeth can be assessed on radiographs to predict sensitivity levels. The vitality of the teeth should be tested, particularly single discolored teeth. Teeth that are nonvital should be root-treated with a good apical seal before whitening treatment. Cervical recession, periodontal health, and any cracking of the anterior teeth should be assessed. Translucency should be measured because highly translucent teeth do not whiten as well; they sometimes appear grayer rather than whiter. Patients should be informed that translucent teeth do not whiten as well.

PREEXISTING SHADE EVALUATION

Before treatment is begun, discuss with the patient the possible shade lightening that can be achieved. This is normally two shades lighter on a normal porcelain shade guide (Vita Classic shade guide) or 1–3 shades lighter on a value-oriented shade guide (Vita 3D master). Shade taking can be done via the normal methods—that is, using the porcelain shade guide or the shade guide supplied with the whitening kit (see Figure 5.5 and Table 5.1). The patient should be fully involved in the shade-taking process, should acknowledge the preoperative shade that was taken, and may sign the notes for verification.

PLANNING THE TREATMENT

It is normally advisable to whiten only one arch at a time so that the patient has the opportunity for a comparison. Often the patient forgets how dark the teeth were to begin with and wants to carry on with the treatment, perhaps unwisely. Both arches can be whitened when time is short, such as for a forthcoming wedding celebration.

It is also essential to discuss with patients that their existing composite restorations may not match after whitening and that it may be necessary to replace these composites with lighter ones after the whitening procedures. Photographs with the shade tab that currently matches the teeth are taken (see Figure 5.7). Intraoral photographs can also be taken. These images can be enhanced so that the patient can see the possible outcome before treatment, but no guarantees are given if the images are enhanced. Other factors to take into account are listed in Table 5.2.

IMPRESSION TAKING

Excellent impressions reproducing the surfaces of the upper and lower teeth should be taken so that whitening trays can be made. Alginate or another accurate material can be used. In mixing the materials, attempts should be made to eliminate as many air bubbles as possible (see Figure 5.6). Alginate mixing machines can be used to reduce air bubbles. A small amount of alginate can be rubbed onto the occlusal surface of the teeth to achieve good detail. Closed-mouth techniques are used to eliminate the possibility of distortion of the mandible. Alginate impressions should be poured and cast very soon to prevent distortion of the casts. Whitening trays are made from these impressions (see Chapter 6).

SELECTING THE APPROPRIATE WHITENING MATERIAL

A vast array of whitening materials is available. It is important to select the appropriate material for each particular patient. The greater the concentration of carbamide peroxide, and the thicker the material, the more quickly the whitening will take place and the less the trays will need to be worn. Some systems have graded concentrations of active agent, such as 5%, 10%, 15%, and 20%, or even 35%, to enable the patient to get used to whitening without experiencing tooth sensitivity. Studies comparing whitening agents have shown that they all work and there is minimal difference among them (Lyons and Ng 1998). There is an inverse relationship: if the concentration of the whitening agent is decreased, the treatment time must be increased. The concentration of whitening gel is restricted to 6% hydrogen peroxide in Europe according to the European directive that was introduced in 2012.

The choice of which whitening agent to use depends on the following information (Table 5.1):

•  The discoloration

The source of the discoloration (see Figures 5.16A and 5.16B)

The form, shape, depth (whether superficial or deep), and extent of the discoloration The existing color (darker teeth will take longer to whiten)

The location of the staining (i.e., within the enamel or dentin) (Touati et al. 1999)

•  The whitening material

The cost of the material (is the cost of the tray fabrication included?)

CE Mark (type and classification)/American Dental Association (ADA) Seal of Approval

Chemical constituents of the base material (hydrogen peroxide, carbamide peroxide or perborate)

Mode of action: pH values?

Dispensing method

Tissue tolerance

Safety studies: have the products been evaluated by the Food and Drug Administration?

Suggested wearing times

Patient-friendly, clear instruction sheets

Ease of use, application

The flavor

•  Patient factors

Existing tooth sensitivity

Lifestyle

Personal schedule

Patient dexterity

Goals for whitening

WHITENING INTRODUCTION

It is customary to perform an oral prophylaxis before any whitening procedure. This may be done by the hygienist or the dentist. However, a study (Knight et al. 1997) showed that patients who experience sensitivity after an oral prophylaxis are more prone to experience sensitivity and other side effects during whitening. Leonard (1998) advised that patients should wait 2 weeks after an oral prophylaxis before beginning the whitening procedure. Written home whitening instructions are explained to the patient. The whitening record sheet (see Figure 5.1) is completed and the patient signs the consent form. A power whitening session can be done to initiate the whitening at the chairside or to motivate the patient to continue whitening at home, but there would be increased cost for this additional procedure.

SEATING THE TRAY

For a full arch

The whitening trays are checked for correct fit, retention, and overextension on the gingival area. If they are overextended, the trays can be trimmed back with small sharp scissors. The rough edge is then polished with a rubber wheel or flame smoothed. The aim is for the tray to fit well, to keep the whitening material in contact with the teeth but not to impinge on the gingivae (see Figure 5.10). The amount of whitening material to be used can be demonstrated to the patient, and the patient is helped to insert and remove the trays (see Figure 5.9). The patient is instructed to place enough material to fill the tray with minimal excess (Leonard et al. 1999) (see Figure 5.11). A demonstration of how to remove the excess whitening material from the soft tissue can be undertaken. Instruct the patient not to swallow the excess but to remove it first using a cotton wool roll, finger, or toothbrush. Patients are instructed to brush and floss their teeth and then to apply the tray with the whitening material in their mouth. They can choose either to whiten their teeth while they sleep or to apply the tray during the day, depending on their schedule.

Supply the whitening material, a few cotton rolls, cotton buds, and the whitening toothpaste (not mandatory) in a home kit. Document the amount of whitening material given to the patient as well as the name of the whitening agent used on the whitening record sheet (Fasanaro 1992) (Figure 5.1). A patient whitening log (see Figure 5.2) is supplied for the patient to document the use of the materials, sensitivity levels, and the amount of time the trays are worn. The patient is instructed to telephone the practice if any adverse reactions are experienced, particularly sensitivity to hot and cold. Normally it is best to start with the whitening of the maxillary teeth because these whiten more quickly. This is thought to be a result of better retention of the upper tray, the effects of gravity, and the reduced effects of salivary flow compared with the mandibular arch.

For single teeth

Full-arch trays are constructed, but patients are instructed to place the whitening material only in the location of the dark tooth. Normally two trays are made. One full arch tray and a second full arch tray with a window cut on either side of the dark tooth so that the patient whitens only the dark tooth in the beginning. Then, the second full arch tray is used to whiten the whole arch. To help patients identify where to place the whitening material, a small notch can be cut into the tray above the tooth (Small 1998). After the teeth are all the same value, the entire arch can be whitened. This could be achieved the other way, by whitening all the teeth first and then titrating the shade by whitening only the single dark tooth.

DISCUSSION OF TREATMENT REGIMEN

The decision about when and how long to keep the trays in the mouth depends on the patient’s lifestyle, preferences, and schedule (see Figure 5.8). Whitening times will vary according to the patient’s schedule. It is useful for the patient to document wearing times so that they can be modified if necessary. Some patients titrate and/or adjust the amount of whitening agent used for certain teeth because they notice some teeth lightening more than others. Some patients report slower whitening of the canine teeth, so they sometimes selectively whiten only the canines for 1 week until the color is the same in all the teeth. This is particularly the case in teeth with multiple shades and in which combination whitening takes place. Higher concentrations of whitening agent (e.g., 15% or 20%) can be used on these canine teeth to whiten them to a similar level as the other teeth (see Figures 5.19A–G).

Some patients prefer to whiten during the day. Wearing the tray during the day allows replenishment of the gel after 1–2 hours for maximum concentration. Occlusal pressure and increased salivary flow dilute the gel (Dunn 1998). Overnight use may decrease loss of the material from the tray owing to decreased salivary flow and reduced occlusal pressure (see Figure 5.13). For maximum benefit per application and compliance with long-term treatment, the whitening trays should be worn at night (Haywood 2000).

HAYWOOD PROTOCOL FOR UNDERTAKING HOME WHITENING

The Haywood home whitening treatment has been used for the last 25 years. This protocol was first published in 1989 but has been updated (Table 5.3). Information about longevity has been reported; the patients who participated in the original study did not need to rewhiten their teeth. Reports have demonstrated up to 17 years of success with this technique of home whitening.

It is important to warn patients that worn lower incisors will still appear discolored (see Figures 5.22A–C); however, there is evidence that the dentin is also lightened during the whitening treatment (Haywood 1995) (see Figures 5.21A–C). Separate fees should be charged for the whitening of the different arches.

Table 5.4 gives typical schedules for different types of tooth conditions.

WHITENING REVIEW

It is best to assess the patient 1–2 weeks after he or she has been wearing the trays. Monitor the oral environment, soft tissue, mucosae, gingival health, and teeth for any adverse reactions. Discuss the length of time for which the patient has been wearing the trays and any problems that have been encountered. Review the patient’s logs. Give the patient a new log sheet and retain the old one to document the clinical notes. Modify any timing of tray wearing if necessary. Check the mouth for gingival irritation. The tray may need to be modified (see Figure 5.9). Take the new shade. Take photographs with the new and old shade tabs to evaluate the shade change. Supply the patient with more whitening material if necessary. Patient compliance is normally better with patients who wear the whitening trays at night rather than during the day (Hattab et al. 1999).

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