Why implant crowns get remade, and how to prevent it

What goes wrong with implant crowns?

There are two separate moments. The first is seat day: the crown won’t go down, it’s high, a contact is open or the shade is off. The second is the years the crown spends in function. This piece is about the first, because that is the part a better Rx can prevent.

Most of the research measures the second. A systematic review by Pjetursson and colleagues (Clinical Oral Implants Research, 2021) pooled 49 studies of ceramic single crowns on implants and reported annual complication rates. Chipping ran at 1.65% a year for veneered crowns and 0.39% for monolithic ones. Screw loosening averaged 0.44% a year, and loss of retention on cemented crowns 1.97%.

Design, material and occlusion all feed those numbers, and some of it starts at delivery: a crown that leaves the lab with the wrong occlusal contacts takes that error into the mouth. On the communication side, incomplete work orders are an old problem. In a survey of 85 lab technicians (The Journal of Indian Prosthodontic Society, 2020), preferred margin and stain map were filled in on only 25% to 50% of fixed prosthodontic prescriptions.

How does a poor scan body capture turn into a crown that won’t seat?

The design starts from the implant position, and the software derives that position from the scan body surface in your file. If that surface is incomplete, the computed position shifts, and the crown carries the error.

Two in vitro studies show the effect. Petchmedyai and Thanasrisuebwong (PLOS One, 2023) simulated gaps in scan body capture at different implant depths. The less scan body was exposed and the bigger the gap in the mesh, the larger the angular and positional deviation of the virtual implant.

Matta and colleagues (International Journal of Implant Dentistry, 2026) raised the soft tissue height and cut defects into the scan bodies. Every error they tested increased deviation significantly, and their advice is to expose the scan body as much as possible and avoid gaps in the scan.

Before you send, check three things in the file:

• The whole scan body is in the mesh, top and flat faces visible, with no holes around it.
• It is fully seated. If tissue or bone kept it from seating, the file shows an implant where there isn’t one.
• The Rx names the scan body (brand and model), because the design matches it to that component’s library.

At check-in we open the file and confirm it is complete before the case moves to design. If the scan body isn’t readable, the case stops there and we contact you rather than design on a position we can’t trust.

Why does the wrong platform cost a whole crown?

Because a screw-retained crown is designed on a titanium base that has to match the implant connection. The right brand with the wrong platform, or a compatible system mistaken for the original, gives you a crown that won’t engage.

On the Rx, write the implant brand, system and platform or connection diameter. If you took an impression, send the impression coping or the analog. At check-in we confirm the component for that system is in stock before the case goes into production.

What happens without an opposing arch or bite?

The crown gets designed with no occlusal reference. It can arrive high, out of contact, or with an excursive contact nobody planned for. With an intraoral scan, that means capturing the opposing arch and the bite in the same session. With an impression, it means sending the opposing model and a bite registration; both are on our check-in list. QC checks occlusion against that opposing arch before the crown leaves the lab.

How do you avoid proximal contact problems?

Capture the adjacent teeth well, especially the surfaces that touch the crown. The technician sets the contact on those surfaces; if the mesh is patchy there, the contact is a guess.

It also helps to set expectations with the patient. Contact loss between implant crowns and natural teeth is common. An umbrella review by Fathi and colleagues (European Journal of Dentistry, 2022) found about 29% of contact points affected, more often on the mesial and in the mandible, and rising over time. The authors recommend telling patients about the risk. A well-set contact at delivery won’t prevent that drift, but a light one starts out open.

What about shade?

A shade with no guide named is the easiest remake to avoid. State which guide you used (VITA Classical or 3D-Master) and the exact code, and for anterior units send a photo with the tab against the adjacent tooth. Our piece on VITA Classical vs 3D-Master covers taking and sending the shade.

What we check at check-in and before a case leaves

These are the lists every case goes through here. If your Rx answers everything in the first column, the case doesn’t stall at check-in.

What this changes on your Rx

A crown that doesn’t come back starts with an Rx that includes: a file with the whole scan body, fully seated; implant brand, system and platform; the scan body used; opposing arch and bite; and a shade with the guide named, plus a photo for esthetic zones. If the case calls for it, ask for design approval in the portal before milling.

Our guide to sending a case to the lab has the full list, and the intraoral scanning guide covers scan body capture in detail. For the restoration itself, see zirconia implant crowns.