How to Reduce Dental Impression Remakes
The Ultimate Guide for Dentists
It’s the moment every dentist dreads. The patient is in the chair, numb and ready for their new crown. You unbox the restoration from the lab, check the fit, and... it doesn't seat. The margin is open, or the contacts are too tight. You have to break the news to the patient: "We need to take a new impression and try again in two weeks."
The disappointment in their eyes is palpable. But beyond the awkward conversation, the cost of a remake is staggering. It’s not just the lab fee (if applicable) or the materials; it's the lost chair time. That 30-minute seat appointment has now turned into a non-billable hour of re-prepping and re-impressing, plus another future appointment.
Remakes are the silent profitability killer in dental practices. Yet, the root cause often isn't the dental lab, but the initial data capture. Whether you are using traditional dental impression putty or modern intraoral scanners, the "garbage in, garbage out" principle applies.
At Sage Dental Arts, based in Oklahoma City, we see thousands of cases come through our doors. We aren't just a manufacturer; we are your partners in precision. We know that many dental professionals haven't received adequate training on the nuances of digital workflows compared to traditional methods. This guide bridges that training gap, offering actionable technical tips to help you get it right the first time, every time.
Why One Impression Often Isn't Enough
In a busy practice, speed is often prioritized. The "one and done" mentality, taking a single fast scan or one quick tray impression, is tempting. But rushing this critical step often leads to that dreaded question later: "Can you get the patient back in?"
Minor errors in the initial capture create a downstream effect. A small tear in the margin of a PVS impression or a bit of saliva obscuring a digital scan forces the lab technician to guess. And when we have to guess, the risk of an open margin or poor fit skyrockets.
We advocate for a "Double-Check Protocol." Whether you are taking physical dental impressions or digital ones, assume the first attempt might have flaws.
- For Digital: Scan, then stop and rigorously inspect the data on a large monitor before the patient sits up.
- For Analog: Inspect the impression under magnification. If there is any doubt, whether it’s a pull, a drag, or a void on the margin, retake it immediately.
Taking three extra minutes now saves three weeks of frustration later.
Mastering the Prep: The Foundation of Success
Great results start before the impression material or scanner even touches the tooth. The design of your preparation dictates how well the lab can fabricate the restoration.
Ideal Prep Design
Modern restorative materials like Zirconium or E.max need specific parameters to function correctly. A smooth transition at the margin is crucial.
- Why it matters: It allows the lab technician to meet the manufacturer's minimum thickness requirements without over-contouring. It also provides space to mask dark underlying tooth structures for a more aesthetic result.
- Avoid Feather Edges: Milling machines struggle with feather edges or inconsistent, jagged margins. They simply cannot create a clean transition, leading to a "sloppy" internal fit.
Avoiding Sharp Line Angles
Digital milling machines use burs that have a specific radius. They cannot mill a perfectly sharp 90-degree internal angle.
- The Issue: If your prep has sharp line angles, the mill will over-machine that area to ensure the crown seats, leaving excess space (cement gap) between the tooth and the crown. This reduces mechanical retention.
- Actionable Step: Round off all line angles, specifically the transition from the axial wall to the occlusal plane. This ensures an intimate fit between the intaglio surface of the crown and your prep.
The Art of Clear Margins
Cleanliness is non-negotiable. Whether you are using traditional dental impression putty or a state-of-the-art scanner, the site must be pristine.
Cleanliness is Key
Your prep site must be free of blood, saliva, and debris. Modern intraoral scanners are incredible pieces of technology, but they cannot see through fluid. If there is blood or saliva pooling in the sulcus, the scanner will interpret it as tissue or tooth structure, resulting in an inaccurate model.
- Protocol: Use a 2-cord technique if necessary to manage tissue and control hemostasis.
- Digital Specifics: Keep your scan times short (5-6 seconds per segment) to prevent fluid accumulation. If you see fluid, stop, rinse, dry, and re-scan.
- Remember: Unclear margins force the dental lab to estimate where the edge of the prep ends. This estimation is the leading cause of open margins and costly recalls. Even for digital dental impressions, a dry field is paramount.
Critical Checkpoints Before the Patient Leaves
Before you send the patient home, run through this checklist. It covers the most common reasons we have to call doctors for new dental crown impressions.
1. Occlusal Clearance
We need space to work. Ideally, you should provide 1.5mm of occlusal clearance.
- Benefit: This provides flexibility if the treatment plan changes and allows for stronger, more lifelike restorations.
- Risk: Insufficient clearance leads to thin crowns that are prone to fracture, potentially voiding the warranty.
2. Adjacent Contacts & Path of Insertion
Tight or broad contacts can prevent a crown from seating fully.
- Technique: Use a Sof-Lex disc to refine the contacts of adjacent teeth. You want them to be smooth, vertical, and parallel.
- Why it matters: This prevents "pinpoint" contacts and food impaction issues. It also creates a clear path of insertion (draw), ensuring the crown slides effortlessly onto the prep without binding on undercuts.
3. Bite Registration
Never blindly trust the digital bite scan.
- Action: Visually inspect the patient's bite intra-orally after the scan. Does the digital occlusion map look like what you see in the mouth?
- Digital Workflow: Ensure you capture a full arch scan to give the software enough data points to stitch the bite accurately. This minimizes chair-side adjustments later.
Digital Workflow: Color View vs. Stone View
If you are using an intraoral scanner, you have a secret weapon that many dentists ignore: Stone View (or monochrome mode).
Color scans look impressive to patients, but they can hide defects. The color texture can camouflage saliva bubbles or blood that mimics gingival tissue. When you switch to Stone View, the scan is stripped of color, revealing the surface geometry in stark detail.
The Rule of Thumb: "If you can't see the margin in Stone View, the dental lab can't see the margin."
When to Re-Scan (Red Flags)
If you see any of the following, do not send the case. Delete the data and re-scan:
- Blood in the scan: It distorts the margin.
- Unclear margins: If the line isn't crisp, the crown won't seal.
- Missing scan data: Holes or "Swiss cheese" areas in the model.
- Divergent contacts: Verify the path of draw is clear.
Efficiency Equals Profitability
Taking an extra five minutes to round a sharp line angle, pack a second cord, or verify a dental crown impression in "Stone View" might feel like a delay in the moment. But compare that to the cost of a 45-minute seat appointment where the crown doesn't fit.
Precision is an investment in your own efficiency. When you provide clean data, you get back a restoration that drops right in; no grinding, no adjusting, just cementing.
At Sage Dental Arts, we are dedicated to manufacturing excellence. We use the latest technology, from CAD/CAM to E.max, to deliver superior results. But we are also here to support you. If you are struggling with remakes or want feedback on your impression techniques, we are just a phone call away.
Ready to stop the remake cycle? Partner with a lab that cares about your profitability. Contact Sage Dental Arts today for a consultation or send us your next case to experience the difference.