In a controlled clinical study published in BMC Oral Health, researchers timed both ways of capturing a patient’s bite. The digital scan averaged about 248 seconds. The traditional tray-and-material impression took roughly 605. Same patients, same mouths, two weeks apart so nobody remembered the first round clearly. Every participant said they preferred the scan.
That gap is the reason the equipment in your dentist’s operatory looks nothing like it did in 2010. And the change runs deeper than your comfort in the chair, because once the impression becomes a file instead of a physical object, everything downstream of it changes too. Your appointment count included.
The 605-Second Problem
You know the old routine even if you never learned the names for it.
A tray full of putty gets pushed onto your upper arch. You sit there breathing through your nose, trying not to gag, while it sets. Then the lower arch. Then a bite registration. The tray goes in a box, the box goes on a courier, and the courier goes to a dental lab that might be across town or in another province entirely.
Meanwhile you get a temporary crown made of acrylic, glued on with cement designed to fail on purpose so it can come off later. You go home with it. You avoid chewing on that side. Two or three weeks later you come back, get frozen a second time, and find out whether the lab nailed the fit.
If it did not, the whole loop starts over.
That was normal dental care and formula for decades, and honestly it worked. Millions of solid crowns came out of it. But it had four failure points stacked in a row, and every one of them cost you time.
What a Scanner Actually Does in Your Mouth
A wand roughly the size of an electric toothbrush handle passes over your teeth. It projects light onto the surfaces and captures thousands of frames per second, stitching them into a 3D model that builds up on a monitor while you watch.
No tray. No setting time. If your dentist misses a spot, they rescan that spot instead of redoing the entire arch.
The model shows up on screen at a magnification you would never get with a hand mirror, which is why a lot of patients end up having a completely different conversation about their own teeth. You can see the crack. You can see the wear facet on the molar you grind at night. Arguing with a photo of your own enamel is harder than arguing with a description of it.
Then the file goes somewhere. That destination is the part that actually matters.
The Milling Unit in the Back Room
If the clinic sends the file to a lab, you have saved the goop and the courier and not much else. The two-visit structure stays.
If the clinic has a mill, the file travels fifteen feet instead of fifteen kilometers. Design software builds the crown against your scanned bite, the dentist adjusts the margins and contacts on screen, and a milling unit carves the restoration out of a solid ceramic block while you sit in the chair.
Depending on the material, there is usually a firing cycle after milling. Lithium disilicate blocks come out of the mill in a soft, chalky blue state and go into a furnace to reach full strength and final shade. That step alone runs 20 to 30 minutes, which is why “same day” in practice means a two-hour appointment, not a fifteen-minute one.
The Birmingham VA dental clinic ran the workflow for a Marine veteran who showed up expecting the usual weeks-long wait and had the design, fit, and delivery finished the same day. That reaction is the standard one. Most people have no idea their clinic can do this until it happens to them.
Where the Same-Day Version Holds Up
Single crowns on back teeth are the sweet spot, which happens to cover most of the crowns you will ever be offered. The evidence there is reasonable. A 10-year follow-up in The Journal of Prosthetic Dentistry examined 426 CAD-CAM lithium disilicate crowns and reported 10-year survival between 94.7% and 95.8%, with success rates in the 93% to 94% range. Most of those crowns, 275 of them, were milled chairside rather than in a lab.
If your molar cracked on a popcorn kernel and needs one unit of coverage, you are squarely in the territory the research supports. Inlays, onlays, and short-span work sit there too.
Where the Lab Still Wins
Here is the part your dentist should be telling you, and some do not.
A University of Leipzig team tracked chairside-milled posterior crowns for 15 years. Twenty-two crowns were available for recall, six had failed, and survival came out at 80.1% with a success rate of 64.2%. That is a small sample from crowns placed in 2006 and 2007 on equipment three generations older than what is sold today, so read it as a limit on certainty rather than a verdict. It is still a useful correction to the brochure version.
Full-arch cases, complicated bites, heavy cosmetic work across the front teeth: these are where a skilled technician spending three days on layering and shade produces something a two-hour mill cycle cannot match. A clinic that mills everything regardless of the case is telling you something about its priorities.
Two Visits or One: A Side-by-Side Look
| Traditional lab workflow | Same-day chairside workflow | |
|---|---|---|
| Impression | Tray and material, roughly 10 minutes | Digital scan, roughly 4 minutes |
| Temporary crown | Yes, worn 2 to 3 weeks | None needed |
| Freezing appointments | Two | One |
| Total elapsed time | 2 to 3 weeks | One appointment, often 2 hours |
| If the fit is off | New impression, new lab cycle | Redesign and re-mill the same day |
| Best suited to | Complex cosmetic cases, full-arch work | Single crowns, onlays, short-span restorations |
Why This Lands Differently in a Winnipeg Winter
Everything above is true in San Diego too. The math changes here.
A second appointment in February means scraping your windshield, budgeting for whatever Kenaston is doing that morning, and taking another block of time off work. A temporary crown that pops off on a Sunday means calling an emergency line instead of enjoying your weekend. Neither of those is a clinical problem. Both are the reason people cancel and let a cracked molar sit for eight months.
Cutting one visit out of the loop removes the exact friction that makes people quit halfway through treatment. That is the real argument for the technology, and it has almost nothing to do with the ceramic.
It also helps to know what your local options are. If you are comparing clinics, a dentist in winnipeg who runs scanning and restorative work under one roof can spare you the referral shuffle between three offices spread across the city, which matters a lot more in January than it does in July.
Five Questions Worth Asking, Borrowed From the Dentists
The Canadian Dental Association publishes a position statement telling dentists how to evaluate a new technology before adopting it. It asks them to assess the published evidence, talk to colleagues already using it, weigh benefits against risks for patient care, complete hands-on training first, and choose training providers who disclose their conflicts of interest.
Flip that list around and you get a decent set of questions for the person holding the scanner:
- How long have you been milling in-house, and roughly how many units so far?
- Which cases do you send to a lab instead, and why?
- What material are you using for my specific tooth?
- What happens if the fit is off after it is cemented?
- Does this cost me more than the lab version, or less?
A dentist who enjoys these questions is a good sign. A dentist who gets cagey about question two is a different kind of sign.
What the Technology Does Not Fix
The scanner does not prep your tooth. The mill does not decide where the margin goes. The software does not spot the crack that brought you in.
A clinical instructor at Boston University’s dental school put it plainly after supervising students on their first same-day restorations: the technology makes ceramic work simpler, but it “does not replace the dental training required from the operator.”
A 2025 scoping review that fed into an FDI policy statement made the same point at the profession level, cautioning against overreliance on digital tools. A poorly prepped tooth scanned in high resolution is still a poorly prepped tooth. The judgment calls that decide whether your crown lasts 5 years or 15 sit entirely with the human, and no amount of hardware moves that responsibility anywhere else. Which is a slightly deflating ending for an article about machines. It is also the honest one.
So What Should You Do With Any of This?
You do not need to shop for a scanner brand. You need to know that the two-visit crown is no longer the only path, that the single-visit version has solid evidence behind it for straightforward cases, and that a clinic willing to explain where it draws the line between chairside and lab work is telling you something true about how it practices.
Next time somebody mentions a crown, ask what happens to the impression after they take it. The answer tells you more about the office than any tour of the equipment would.
