How to write a crown Rx your lab never has to call about

A crown Rx needs no phone call when it answers six questions before the lab has to ask.

Which tooth, which material, what shade, where the margin is, how the bite should meet, and when you need it.

Four of those take one line each. Shade and anything unusual about the preparation take a little more.

This guide goes through each field, with an example of the same crown prescribed two ways.

Six questions a crown Rx answers before the lab asks

A checklist of the six questions a crown prescription answers: which tooth, which material, what shade, where the margin is, how the bite should meet and when the crown is needed.

• Which toothIn FDI notation, checked against the scan
• Which materialNamed in full, or the lab is asked to choose
• What shadeThe shade, its guide and a photo with the tab
• Where the margin isAnything hidden or tight, described
• How the bite should meetThe bite scan, and how firm you like the contacts
• When you need itThe day back, and the day the patient is booked

The same crown, prescribed two ways

Both of these describe one crown on a lower left first molar. Only one can be made without a question.

The thin version can still be made. It leaves five decisions to the lab, and a careful lab will phone about each.

Tooth and restoration

Write the tooth in FDI notation, with the word “tooth” in front. Check it against the tooth that is prepared in the scan.

Then name the restoration fully. Say if it is full coverage or partial, and if it joins to anything beside it.

If the crown goes on an implant, the lab needs a different set of details. Implant cases: what the lab needs from the practice covers them.

Material

Name the material you want. “Zirconia” narrows it, and “full-contour zirconia” settles it.

If you would like the lab to choose, say that in words. Then give it what it needs to decide.

• How much room there is above the preparation
• What the crown bites against
• How much of it shows when the patient smiles
• How you plan to cement or bond it

The last item is easy to leave out. The way a crown is fixed in place affects which materials suit it.

What the lab needs for each material

Each material raises its own question at the bench. Answer it on the Rx.

Shade

Give the shade, and name the shade guide it was read from. The same code means different colours on different guides.

For a back tooth, one shade and a photo are often enough. For a front tooth, describe how the colour changes from the gum line to the edge.

Send a photo with the shade tab held beside the tooth, in the same plane. The lab reads far more from that picture than from a code.

Say if the patient has asked for a change in colour, such as a lighter result than the teeth beside it.

For a translucent ceramic, add the stump shade. The prepared tooth shows through, and a dark one changes the result.

Shade communication with your dental lab covers lighting, photos and custom shade visits.

Margin and preparation

The lab reads the margin from your scan. Anywhere it is hard to see, the lab is deciding for you.

So tell the lab what you know and it cannot see.

• Where the margin dips below the gum
• Any spot where tissue or moisture hid it during the scan
• A place where you would like the margin moved slightly
• Whether to call you about a doubt, or use its judgement

Mention anything tight. If there is little room above the preparation, say so, and say what you want done about it.

A lab that knows about a limit can plan for it. A lab that finds it at the bench has to stop.

Bite and contacts

Say how you want the crown to meet the opposing tooth. Dentists differ on this, and labs remember preferences once they are told.

Note what it bites against. A natural tooth, a ceramic crown and a denture tooth each call for something different.

Send the bite scan every time. Without it, the lab sets the occlusion from two arches that are not related to each other.

Add how firm you like the contacts with the neighbouring teeth. One sentence now saves an adjustment at the seat.

If the bite felt unusual at the appointment, say so. The lab cannot see a slide or a habit in a scan.

Flag anything out of the ordinary.

• The patient grinds or wears a night guard
• The crown sits under the clasp of a partial denture
• A neighbouring tooth is about to be restored as well
• The provisional worked well and you would like its shape copied

Dates and files

Give two dates: the day you need the case back, and the day the patient is booked. “ASAP” tells the lab nothing it can plan around.

List every file you are sending. The lab can then see at once if one failed to arrive.

Send a scan from before the preparation if you have one. It shows the lab the shape the tooth used to be.

Name the files so the lab can tell them apart. The patient’s initials and the arch are enough.

Say when you want a call

A good Rx also tells the lab what to do with a doubt.

Some dentists want a call about anything unclear. Others would sooner the lab used its judgement on small things and kept the date.

Write your rule down once. “Call me about margins and shade, use your judgement on contours” is enough.

Without it, the lab has to guess which kind of dentist you are. A cautious lab will call every time.

A check before you send

Thirty seconds here is worth a day later.

• The tooth number matches the prepared tooth in the scan
• The material is named, or the lab has been asked to choose
• The shade names its guide, and a photo is attached
• Anything hidden or tight is described
• The bite scan is attached, and the contact preference is stated
• Both dates are filled in
• Every file sent is listed

Most of this never changes for a given dentist. Ask your lab to keep your usual answers on file, so each Rx only records what is different.

Our dental lab prescription checklist covers bridges, implants and removable work the same way.

Labs see the other side of this at intake. Incomplete prescriptions shows what a gap costs them.

After the seat, tell the lab how it went. A note on the contacts, the bite and the shade makes the next crown closer.

How to give your dental lab feedback covers what to say and when.

On Tusko, the Rx goes to the lab with the scans, the photos and the date in one submission. If the lab still has a question, it asks on the case.

See how it looks for practices.