10.5 Vital and Non-Vital Tooth Whitening

10.5 Vital and Non-Vital Tooth Whitening

Quick Answer: Whitening appears twice in the Domain Description: assisting with vital and non-vital whitening (5.7.9) and performing vital whitening (7.7). Whitening agents are peroxides. Hydrogen peroxide releases free radicals that break large pigmented molecules into smaller, lighter ones. Carbamide peroxide breaks down into hydrogen peroxide and urea; 10% carbamide peroxide is roughly 3.5% hydrogen peroxide.

• Vital techniques: in-office (high-concentration hydrogen peroxide with a gingival barrier) and at-home custom trays.
• Non-vital teeth: treated from inside the pulp chamber (the "walking bleach" technique) after a sound root canal filling and a cervical barrier.

Record the starting shade before isolation, because dehydrated teeth look lighter. The most common side effect is temporary tooth sensitivity.

1. Indications and Contraindications

Before whitening, the dentist examines the patient and takes radiographs if needed. Stains, calculus and caries are managed first. The patient also needs a realistic explanation of results, cost, time and side effects, which is part of informed consent.

2. Vital Whitening Techniques

In-office ("power") whitening

• Agent: high-concentration hydrogen peroxide gel (about 25% to 40%), applied by the clinician.
• Protection: retract the lips and cheeks. Protect the patient's eyes, skin and lips. Apply a light-cured resin gingival barrier (or a dental dam) to cover the gingival margins and interdental papillae before the gel goes on.
• Application: apply the gel to the facial surfaces in the cycles and timing the manufacturer specifies. Evacuate and wipe off the gel between cycles. Some systems use a light, although evidence that the light adds benefit is limited.
• After treatment: remove the gel, rinse and remove the barrier, check the gingiva, record the new shade and give post-operative instructions.

At-home tray whitening

• Agent: lower-concentration carbamide peroxide (commonly 10% to 22%) or hydrogen peroxide (about 6% to 10%), dispensed by the office.
• Wear time: a few hours a day or overnight, for about two to four weeks, according to the product and the dentist's prescription.
• Advantages: gradual, adjustable results at lower cost. Disadvantages: depends on the patient's compliance, and gel can irritate the gingiva if the tray is overfilled.

Fabricating a custom whitening tray (competency 7.7.2)

1. Take maxillary and mandibular alginate impressions (section 11.1), disinfect them and pour them in dental stone.
2. Trim the cast into a horseshoe shape with a flat base, and remove any bubbles or nodules.
3. If the dentist prescribes reservoirs, apply a thin layer of light-cured block-out resin (about 0.5 mm) to the facial surfaces, stopping short of the gingival margin. Cure it.
4. Heat a soft vinyl or EVA tray sheet in the vacuum former until it sags, then pull it down over the cast.
5. Cool the tray, remove it and trim it. Follow the gingival scallop, just short of or just at the gingival margin as the dentist prefers, so the material does not irritate the gingiva. Smooth the edges.
6. Try in the tray, check comfort and coverage, and teach loading and wear.

3. Recording the Shade (Competency 7.7.4)

• Record the shade at the start of the appointment, before isolation, retraction or drying. Dehydrated teeth appear lighter and give a falsely good result later.
• Use a shade guide (for example, the VITA Classical tabs arranged in order of value, from lightest to darkest) under consistent, colour-corrected light. Take standardized intraoral photographs with the shade tab in view.
• Record the shade of the maxillary central incisors and canines (canines are usually darker).
• After whitening, recheck the shade once the teeth have rehydrated (often one to two weeks later). Wait about two weeks before bonding new composite restorations, because residual oxygen reduces bond strength and the shade has to stabilize.

4. Non-Vital (Internal) Whitening

Non-vital teeth darken when blood breakdown products (hemosiderin) or residual pulp tissue and materials stain the dentin from inside.

1. Confirm a sound root canal filling with a radiograph.
2. Isolate with dental dam.
3. Remove material from the pulp chamber and remove gutta-percha to a few millimetres below the cementoenamel junction.
4. Place a cervical barrier of glass ionomer or resin-modified glass ionomer (about 2 mm thick) over the gutta-percha at about the level of the cementoenamel junction. This blocks peroxide from leaking through dentinal tubules into the cervical periodontal ligament, where it can cause external cervical root resorption.
5. Walking bleach technique: pack a paste of sodium perborate (mixed with water or with low-concentration hydrogen peroxide) into the chamber and seal it with a temporary restoration. The patient returns every few days to a week, and the paste is replaced until the shade is acceptable.
6. Restore the access cavity permanently with bonded composite after the shade has stabilized.

Heat-activated ("thermocatalytic") techniques are avoided because they increase the risk of resorption.

5. Side Effects and Effects of Improper Use (5.7.9.3, 7.7.6)

6. Patient Instructions

• Brush and floss before inserting the trays. Place a small drop of gel on the facial side of each tooth's space in the tray, seat it and wipe away any excess.
• Wear the trays only for the prescribed time. Remove them, rinse the teeth and clean the trays with cool water, then store them in their case.
• Avoid coffee, tea, red wine, colas and tobacco during treatment.
• Report increasing sensitivity, gum soreness or white patches on the gingiva.
• Keep gel out of reach of children, and store it as directed (some products need refrigeration).