Bleaching trays.
A whitening tray has one job: hold gel against the teeth and keep it off the gingiva. Fit is what determines whether it does either.
Why custom trays matter
A well-fitting tray keeps the gel in contact with the enamel for the full wearing period, which is what produces a result. A poorly fitting one lets gel escape, dilutes it with saliva, and pools it against the gingival margin where it causes irritation.
The commonest complaints from home whitening — poor result, gingival sensitivity, uneven shade — are frequently tray problems rather than gel problems.
Trays are also thin and inexpensive relative to the treatment they deliver, which makes economizing on them a poor trade.
Scalloped or straight
A scalloped tray follows the gingival contour and stops at the margin, which minimizes gel contact with the tissue and reduces irritation. It is the usual choice for a patient with sensitive gingivae or where a high-concentration gel is being used.
A straight-cut tray extends slightly onto the gingiva and seals better, which improves gel retention. It suits lower-concentration gels worn for longer periods.
Say which you want. It is a clinical preference and both are legitimate.
Reservoirs
Reservoirs — small spaces blocked out on the labial surfaces of the cast before forming — create room for gel. Whether they are necessary is debated and depends on the gel and the protocol.
They do increase the volume of gel held against the tooth, and some manufacturers specify them. They also make the tray slightly less retentive and can increase gel escape at the margins.
State whether you want reservoirs and on which teeth. Without instruction the laboratory applies its standard, which may not match your protocol.
Records
An accurate impression or scan of the arch, capturing the full clinical crowns and a little beyond the gingival margin so the tray can be trimmed accurately.
Distortion is the usual problem. An alginate impression that has been left before pouring, or a tray that contacted teeth, produces a cast that is subtly wrong — and a tray that does not seat evenly.
Note any restorations, particularly anterior crowns or veneers, since they will not lighten and the patient needs to understand that before starting.
Instructions to the patient
How much gel, where to place it, how long to wear, and what to do about sensitivity. Also what not to expect: existing restorations do not change shade, and a patient who whitens after restorative work will end up with restorations darker than their teeth.
Where restorative treatment is planned, whitening should be completed first and the shade allowed to stabilize before a definitive shade is taken.
Sequencing with restorative treatment
Whitening should be completed before definitive restorative work in the aesthetic zone, with an interval for the shade to stabilize before a definitive shade is taken.
Shades continue to change for a period after active whitening finishes, and a restoration matched immediately afterwards is frequently too light once the teeth settle. Two weeks is a commonly used interval.
A patient who whitens after restorative work ends up with restorations darker than their teeth and no way to correct it short of replacement. Raise it before treatment, not afterwards.
What to put on the prescription
Note bleaching trays under Special Instructions with the arch or arches, whether scalloped or straight, and whether reservoirs are wanted and where.
Mark any teeth to be excluded from the tray, and note existing restorations in the arch.
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Digital scans and conventional impressions are both accepted. Cases move by UPS and Purolator, and Fairmont works with practices throughout British Columbia and across Canada.