A crown remake adds a new appointment, another injection, another temporary, another lab cycle, and a patient who expected the case to be finished. In a busy restorative schedule, even one remake can disrupt the afternoon.

From the lab bench, the causes are usually familiar: problems with margins, scans, bite records, reduction, contacts, shade, or missing instructions.

At Palm Beach Dental Lab, many remake conversations start with relatively small problems, such as a hidden margin, an unstable bite, a missing shade photo, or a prescription that leaves too much to interpretation.

A 2026 multicenter audit of 40,344 fixed prosthodontic restorations reported a 6.9% remake prevalence for crowns. The leading remake reasons were margin-fit discrepancy, proximal-fit issues, and improper fit.¹

Many of the problems that lead to crown remakes arise before the restoration is designed, when incomplete information leaves the technician to make a judgment about the case.

Here are seven areas to check before the case leaves the operatory.

1. The margin is hard to read

A crown is at risk when the lab cannot clearly read the finish line. Blood, saliva, tissue, scan noise, drag, voids, and rough preparation edges can all hide the margin. Once that happens, the technician has two choices: stop and ask for clarification or make a judgment call. The latter can contribute to an open margin, short margin, overextension, or a crown that requires substantial chairside adjustment.

If the margin is buried under tissue or lost in a shiny, wet scan, the design is already carrying additional risk. A digital workflow helps, but the scanner can capture only what the clinician exposes and dries.

Before submitting the case, rotate the scan and inspect the margin from the occlusal, buccal, and lingual views. If the finish line disappears for even a short section, rescan that area.

If the margin takes too long to identify on the screen, it is worth reassessing the scan before sending the case.

READ MORE | What's the best type of crown prep?

2. The impression or scan carries too much noise

A clean scan or impression gives the lab a clean starting point, while excess noise can introduce problems before design begins. Saliva, blood, bubbles, pull marks, tray movement, missing interproximal data, or scan stitching errors can change the way the crown seats. Small errors at the capture stage can become larger problems at try-in.

Digital impressions can produce accurate restorations, and clinical research has shown strong results for intraoral scanning in crown fabrication.^2,3 However, the quality of the records still depends on how they are captured.

Common scan problems include chopped distal surfaces, incomplete adjacent contacts, shiny margin areas, and missing opposing anatomy. In conventional impressions, common problems include voids, drags, thin material around the margin, and distortion during removal.

Review the scan before dismissing the patient, including the preparation, adjacent teeth, opposing arch, and bite relation. For conventional impressions, check the margin under magnification before sending the case. If the finish line is not visible in the impression, the lab will not have the information needed to reproduce it accurately.

3. The preparation does not leave enough room

A crown needs space for material strength, anatomy, esthetics, and occlusion. When the preparation is too tight, the lab has to fit the restoration into a space that may not support the requested result. The crown may become thin, flat, bulky, high in occlusion, or weak in a functional area.

This is common with second molars, short clinical crowns, heavy bites, and cases in which esthetics demand more translucency or layering.

Material choice also matters. Monolithic zirconia, lithium disilicate, layered zirconia, and PFM restorations do not have the same spatial requirements or design and cementation considerations.

Research on ceramic fixed prostheses has linked marginal and internal adaptation with preparation design and finish-line form.⁴ Adequate space is therefore important both for the restorative material and for the intended anatomy.

Before scanning, check occlusal clearance, smooth sharp internal angles, remove unsupported enamel, and tell the lab when clearance is limited.

For example, a note such as “minimal clearance on distal occlusal, keep zirconia monolithic” gives the technician specific direction when designing the restoration.

4. The bite record does not match the mouth

A crown can fit the die and still fail in the chair when the bite record is inaccurate. If the jaw relationship is shifted, incomplete, or unstable, the crown is designed from incorrect information. The result may be a high crown, light occlusion, heavy excursive contact, or a restoration the patient immediately perceives as incorrect.

This problem can occur in posterior crowns, implant crowns, bruxers, deep bites, and cases with missing opposing contacts.

For digital cases, the buccal bite scan needs enough shared anatomy to stitch correctly. For conventional cases, bite material must be fully seated and stable. Even a small shift can affect the resulting occlusion.

The lab designs to the bite record you send. If the opposing arch or bite scan is inaccurate, the crown anatomy may look appropriate on the screen but still be wrong in the mouth.

Add a short note when the patient has a heavy bite, wear facets, implant support, group function, canine guidance, or a known occlusal preference. Those details give the technician additional information for shaping the crown appropriately.

5. Contacts and contours are left to guesswork

Proximal contacts and crown contours are another source of remake calls. A crown may seat well but still feel too tight, too open, bulky, flat, or difficult to clean. The lab needs clear adjacent-tooth data, tissue shape, and clinical direction to design contacts that function appropriately in the mouth.

The 2026 fixed prosthodontic audit found proximal-fit issues among the top reported remake reasons.¹ Contacts are also among the features dentists assess at delivery.

Food traps, rotated teeth, open contacts on the opposite side, old Class II composites, and drifting adjacent teeth should be described on the prescription. If the patient already packs food between nos. 18 and 19, for example, the lab should know before designing no. 19.

A note such as “Slightly firm mesial contact, patient has food trap distal” provides information that may not be apparent from the scan alone.

Contours require similar attention. A crown that is too bulky around tissue can irritate the gingiva. One that is too flat may look unnatural or collect food, while poor emergence can make hygiene more difficult.

The scan documents the existing anatomy, but the prescription can identify the clinical features that require particular attention.

6. Shade information is too thin

Shade remakes often begin with a single shade-tab number. That may be adequate for a posterior molar in a forgiving area, but it provides limited information for anterior crowns, single centrals, lithium disilicate cases, layered zirconia, dark stumps, and patients with high esthetic expectations.

Shade is affected by lighting, tooth dehydration, adjacent teeth, stump shade, material translucency, surface texture, and characterization.

Dehydration can change tooth color during treatment, which can affect shade matching.⁵ Shade photos are therefore best taken early, before the teeth become dehydrated.

For esthetic cases, send photos with the shade tab in the same plane as the tooth. Include the full smile, retracted view, close-up with shade tab, and stump shade when needed. If the patient has a dark preparation or old endodontic discoloration, include that information as well.

The technician must use those records to reproduce color, value, translucency, texture, and shape. A single designation such as “A2” may not provide enough information for a demanding esthetic case.

7. The prescription misses the clinical intent

A crown prescription should tell the technician what you want made, how it should function, and what relevant details cannot be seen from the scan alone. Missing material, shade, margin preference, occlusion notes, implant parts, or due dates can slow the case and leave important decisions unresolved.

Communication through work authorization has been studied in fixed prosthodontics. One survey found that information such as pontic design, staining diagram, and preferred margin was completed at lower rates than basic patient information.⁶

A complete prescription does not need to be lengthy, but it should address the information the technician needs before design begins.

For a crown, that usually includes the material, shade, tooth number, margin, contact preference, occlusion, special anatomy, photos, and due date.

For implant crowns, also include the implant system, platform, scan body, screw-retained or cement-retained preference, and access-hole preference.

Providing these details reduces the number of clinical decisions the technician must make without additional context.

A 60-second crown remake prevention check

Before sending the next crown case, take a final look at the records:

• Can the margin be seen all the way around?
• Does the scan or impression show clean adjacent contacts?
• Is the bite record stable?
• Is there enough room for the material selected?
• Did you include shade photos when esthetics matter?
• Did you note occlusion, contact, or contour preferences?
• Does the prescription answer the lab’s likely questions?

This review can identify missing or unclear information before the patient leaves and before the restoration enters the design process.

Preventing crown remakes depends on consistently providing readable margins, accurate records, adequate restorative space, and clear clinical instructions. These records give the lab the information needed to design the restoration around the clinical requirements of the case.  

References

1. Alkadi L, Alsuhaibani M, Altuwaijri K, et al. Prevalence and associated factors of laboratory remakes in fixed prosthodontics: a multicenter audit in Riyadh, Saudi Arabia. Saudi Dent J. 2026;38:16. doi:10.1007/s44445-025-00110-2
2. Shah N, Thakur M, Gill S, et al. Validation of digital impressions’ accuracy obtained using intraoral and extraoral scanners: a systematic review. J Clin Med. 2023;12(18):5833. doi:10.3390/jcm12185833
3. Lee J-H, Son K, Lee K-B. Marginal and internal fit of ceramic restorations fabricated using digital scanning and conventional impressions: a clinical study. J Clin Med. 2020;9(12):4035. doi:10.3390/jcm9124035
4. Pál A, Papócsi P, Kelemen K, et al. Impact of finish line designs on the adaptation of ceramic fixed dental prostheses: a systematic review and network meta-analysis. BMC Oral Health. 2025;25:1085. doi:10.1186/s12903-025-06433-0
5. The effect of isolation and dehydration on shade matching. Compend Contin Educ Dent. 2022;43(5):E9-eE12.
6. Shetty SH, Pawashe KG, Sanyal P, Sushma R. A study to assess communication hindrances by the means of work authorization for fixed dental prosthesis: a survey. J Indian Prosthodont Soc. 2020;20(2):208-213. doi:10.4103/jips.jips_475_19