Tooth Shade Guide: Thirty-Eight Steps, Measured Not Guessed

Thirty-eight steps separate the most yellow tooth from the whitest, and UpWhiten reads yours on an instrument before any gel is opened. Until somebody reads your teeth, “whiter” is a feeling you check in a bathroom mirror.

That scale is NanoChroma™, and it runs from S40, the most yellow, to S2, the whitest. Most dental offices still match the shade by eye against a sixteen-tab guide, held up beside your tooth.

That gap is the point of Predictive Whitening™. It reads your colour before any gel is opened. The specialist sets your target and your rounds against that reading, then reads the same teeth again at the end. You are buying a shade, not sessions.

A box of strips has no reading at all. It cannot tell you where you started, so it cannot tell you when to stop. You keep buying, every few months, for years.

How are tooth shades measured?

Tooth shades are measured two ways, and only one of them leaves you with a number. An instrument reads the colour off the tooth. A person holds a tab beside the tooth and picks whichever looks closest.

Across six pooled in-vivo studies, instrument readings were more accurate than visual matching, and spectrophotometers, digital cameras and smartphones all beat the eye.[1] The same review says matching by eye is subjective, and shifts with the light, the observer and the tooth itself.[1]

An earlier review of twenty-six studies concluded a spectrophotometer may give the most precise reading of the two methods.[3]

In the studio a Certified Whitening Specialist takes the NanoChroma™ reading before any gel is opened, writes it down, and takes it again at the end. You leave with a reading, where a dentist’s tab leaves an opinion and a box of strips leaves a guess.

How do VITA classical and 3D-Master differ?

VITA classical and 3D-Master differ in what they order the tabs by. Classical sorts sixteen tabs into four letter families by hue, so two neighbouring tabs are not an even step apart. 3D-Master orders its tabs by lightness first, then chroma and hue.

Whitening trials read on both, and the bleached version of 3D-Master is built for the range whitening moves through. In a 2026 lab study on extracted molars, researchers read colour on both guides and on a spectrophotometer. Charcoal powder and violet toning changed almost nothing, and the charcoal left grooves in the enamel.[7]

Both guides are still tabs. Somebody has to look, in whatever light the room is giving, and decide. An advert counting tabs on the sixteen-tab guide is counting a different ruler. The two numbers do not trade.

What does a shade change mean?

A shade change means the distance between two readings, and it only means something when the same instrument took both. One trial ran three routes to the same finish, six grades of whitening. Whitening strips needed nearly thirty-two treatment cycles, a dentist’s tray just over seven, and the in-office arm just over three.[5]

That trial timed a supervised chair route, so the three cycles measure supervision, not who owns the chair. The chair visit is the opener at a dental office. The tray you take home is the real product, and nobody reads a shade at your kitchen sink.

A single supervised session does measurable work. One hundred and thirty-five adults had a professional chair treatment, and their colour and shade had both moved by day seven.[6]

Some changes do not hold. In one trial, both drugstore systems relapsed in colour.[8] You buy the next kit, and the one after that.

On the studio’s own records to 12 September 2026, one whitening course moved twenty-eight steps, from S34 to S6. Those are invoice readings on one instrument, before and after, not a tab somebody held up on the day.

Why can photographs and readings disagree?

Photographs and readings disagree because a camera records the light in the room and the water in your teeth. Both move within the hour.

Researchers measured thirty volunteers’ teeth while they dried out. After half an hour, 85% had passed the threshold a person would call unacceptable. A day later, 90% read back under the threshold a person can even see.[2]

A tooth read straight out of a dry half hour reads whiter than it will tomorrow. Nobody at a dental office measures your teeth again a week later. NanoChroma™ reads yours again at every session, and your final reading comes weeks later, at a visit of its own.

Lighting decides the answer when a person is the instrument. One hundred and two dental students matched shades twice, under the operatory light and under a light-correcting device. Their scores rose with the corrector.[4]

What your course actually moved sits in two readings, taken on one instrument, in one chair, weeks apart.

How many shades can whitening move?

It is possible to move all thirty-eight steps of the NanoChroma™ scale, and where you stop inside them is your genetic limit. Nobody honest promises you that number in advance.

Your ideal shade is the brightest one that still reads as yours. The whites of your eyes are the ceiling nature set, and a tooth brighter than they are reads as a set of veneers.

“I don’t know how white I would want it to be.”

— Jason L.

Nobody does, before the reading. The specialist sets your target against your first number.

Your genetic limit shows up as a plateau. The readings stop moving between sessions, because the colour left is the tooth’s own dentine and not stain. A strip user never learns this, and keeps buying boxes for years.

The Ideal Shade Package is built on that. It buys you unlimited sessions until you reach your ideal shade or your genetic limit, at no extra cost, and one number covers all of them. You hear that number at the free Complimentary Shade Consultation, after the reading. Payment plans spread it monthly.

Whitening is a side line at a dental office and the only line here. UpWhiten counts 1,000+ customers, every one of them here for whitening and nothing else. On the same records, the median client goes from first visit to final reading in about five weeks.

What a first reading involves, and what happens in the room, is on a whitening session in the Ottawa studio.

What reads your shade, route by route

This table lists what actually reads your colour on each route, how fine that ruler is, and what you can check afterwards.

A reading has limits. A crown, a veneer or a bonded front surface holds the colour it was made in, and the instrument reads it unchanged. A tooth darkened from the inside by an old injury reads differently again, and that is a dentist’s question, not a shade one.

Where the scale stops

This page settles what a shade number means and who holds the ruler. What those readings look like on real teeth is on before and after readings from finished courses.

How long a number holds before coffee reloads it sits on how long a whitening shade holds. The route-by-route version of the whole argument is Teeth Whitening: Methods, Results and Safety.