Common Prescription Errors.
Most cases that pause in the laboratory do so because of something absent from the prescription rather than something wrong with the impression. These are the omissions that recur.
Material left to the laboratory
Doctor's choice appears on a great many prescriptions, and it is almost always the wrong instruction. Material selection depends on clearance, isolation, function, antagonist and aesthetic demand — and the laboratory can assess exactly one of those from a die.
When we choose the material, we are choosing conservatively, which usually means selecting for strength. That may be entirely right, or it may deliver a monolithic restoration for a case where you were expecting layered aesthetics. Neither of us finds out until the seat appointment.
If you genuinely want a recommendation, ask for one and give us the clinical picture to base it on. That is a different request from leaving the box blank.
Shade without the guide
A2 is not a complete instruction. It means one thing on the VITA classical guide and something else on 3D-Master, and the two systems are organized on different principles — classical by hue family, 3D-Master by value first.
Write the guide name alongside the shade every time. It takes two words and removes an entire category of error. Where the match falls between tabs, say so and name both, because that is more informative than rounding to one.
For anterior and shade-critical work, a shade designation alone is thin information regardless of the guide. Photographs with the tab in frame carry far more, and they are what the ceramist actually works from.
No antagonist noted
What the restoration occludes against changes the design. A natural tooth with intact enamel, an existing ceramic restoration, a gold restoration, an acrylic denture tooth and an unopposed space all call for different material and different surface treatment.
This is rarely written down, and it is one of the more consequential omissions. A ceramic restoration opposing intact natural enamel needs particular attention to polishing, because a rough ceramic surface abrades the antagonist steadily over years. That is a design decision we can only make if we know what is on the other side.
Ambiguous or contradictory instructions
Prescriptions that ask for maximum aesthetics and maximum strength on a preparation with limited clearance are asking for something that does not exist. Prescriptions specifying a knife-edge margin with an all-ceramic material are internally inconsistent. Prescriptions requesting a screw-retained implant restoration where the access would emerge through the incisal edge need a conversation, not a fabrication.
These are not laboratory problems in the sense that we can solve them. They are decisions that have to come back to you, and each one costs a phone call and a delay. Reading the prescription back once before it goes in the box catches most of them.
Implant cases missing the hardware detail
An implant case needs the implant system and product line, the platform diameter, and the connection type. It needs to say whether a screw-retained or cement-retained restoration is intended, and whether a stock or custom abutment is expected.
None of this can be inferred reliably from a scan or an impression. Where any of it is uncertain, a photograph of the component packaging from the placement appointment resolves it immediately, and is far quicker than a sequence of messages trying to identify a connection from geometry.
Known defects not flagged
If you know the distal margin is uncertain, the bite record was difficult, or the impression has a small void you judged acceptable, say so. Sending the case with a note lets us plan around the issue or call you immediately.
Sending it without a note means we discover the problem partway through fabrication, and the case stops at a less convenient point. The disclosure costs nothing and routinely saves days.
Dates written without context
A date on its own tells us when you want the case. It does not tell us what happens if that date cannot be met, which is the information that actually governs how a case is sequenced.
A crown for a patient flying out the following week, a case being seated alongside three others at a single long appointment, and a routine restoration with a flexible review are three genuinely different situations. Where the date is firm and the reason is clinical, saying so lets us tell you early if something will not work rather than late.
The corollary is that a case marked urgent as a matter of habit stops carrying information. If everything is urgent, nothing is.
Remakes and adjustments sent without the reason
A restoration returned for adjustment with no explanation is the hardest kind of case to handle well, because the fault is frequently not visible on the restoration itself.
A crown that would not seat may have been obstructed by an undercut, by a proximal contact, by residual cement, or by a preparation that has been adjusted since the record was taken. A restoration returned for shade may have been assessed on a dehydrated tooth. Without knowing what you observed, we are inspecting a restoration that may be entirely correct.
Tell us what happened: where it bound, what you adjusted, what the patient said, whether anything changed clinically between the impression and the seat appointment. That converts a guess into a diagnosis, and it is the difference between a remake that solves the problem and one that repeats it.
What a complete prescription contains
Practice and doctor identification with a reachable number. Patient identifier. Tooth numbers and the restoration type. The material, stated explicitly. The shade with the guide name. The margin type prepared. The antagonist. The date you need the case. Any constraint, uncertainty or priority that would change a design decision.
For implant work, add the system, platform, connection and intended retention. For anterior work, add photographs. That is the entire list, it fits on one form, and a case carrying all of it will almost never need a call.
In short
- Doctor's choice defaults to a conservative, strength-led selection
- Always name the shade guide — A2 differs between classical and 3D-Master
- Record the antagonist; it changes material and surface treatment
- Implant cases need system, platform, connection and intended retention
- Flag known defects on dispatch instead of letting us find them
More on laboratory communication
Discuss a case
Where a case sits between options, a short conversation before preparation is usually quicker than resolving it afterwards.