Digital dental impressions vs traditional moulds

Dr James Tran

September 20, 2026 · Patient Education · 5 min read

The choice between a scanner wand and a tray of impression material usually comes down to what is being made. For a single crown, a bridge on natural teeth or a set of aligners, the evidence suggests the two methods give a similar fit. For a full denture or a bridge across a whole jaw of implants, the choice is less clear cut, and a tray is still often used.

This guide goes through the common treatments one by one, so you know what to expect and why.

Two ways of recording the same teeth

A traditional mould, or conventional impression, uses a tray filled with a soft material such as alginate or silicone. It is pressed over the teeth and held still for a few minutes while it sets, then removed and usually poured in stone to make a model. A digital impression uses an intraoral scanner: a slim wand with a camera that is moved around the teeth while software builds a 3D model on a screen. Nothing has to set, and the file can go straight to the lab.

If you mainly want to know how each one feels in the chair, our companion article on what a digital scan and a putty impression are like covers the appointment itself.

A treatment room at Lumi Dental with a 3D scan of a patient's teeth displayed on the screen — A finished intraoral scan appears as a 3D model that can be turned and checked before it goes to the lab.

Crowns, onlays and bridges on natural teeth

This is where the research is most settled. A 2025 overview of 28 systematic reviews in the Journal of Prosthetic Dentistry (Kaitatzidou and colleagues) found no statistically significant difference in accuracy, or in the fit of the finished restoration, between digital scans and conventional impressions for crowns and short bridges. The authors also noted that many of the reviews they pooled were of low methodological quality, so the evidence has limits.

In practice, the factors that matter most are the ones that affect any record: a dry field, gums that are not bleeding, and a clear view of the edge of the preparation. If a crown has come loose or a temporary has dropped out, our guides on what to do when a crown falls off and a temporary crown that has come off explain the next steps.

Aligners, retainers and guards

Clear aligner treatment is planned from a digital model of the teeth, so a scan is the natural starting point. Retainers, night guards and sports mouthguards can be made from either a scan or a mould. A stored scan has a practical advantage here: if a retainer is lost, a new one may be able to be made from the existing file, provided the teeth have not moved. Our article on retainer types and how long to wear them covers the options.

Implants: one or two are straightforward, a full arch is debated

For single implants and short implant bridges, the Kaitatzidou overview again found no significant accuracy difference between digital and conventional methods. Full-arch implant bridges are different. That overview reported conventional impressions outperforming digital scans for complete-arch fixed prostheses, while a 2026 meta-analysis in the Journal of Prosthodontics (Alfaraj and colleagues), mostly drawn from laboratory studies, concluded that digital methods can achieve comparable accuracy. When the evidence is split like this, the dentist's technique and the specific system used matter a great deal, and your dentist may add extra checks of the fit before the final bridge is made.

Full dentures still often start with a tray

A full denture rests on gum, not teeth, and its seal depends on the edges reaching the right depth in the soft tissue of the cheeks and floor of the mouth. A 2026 scoping review in the Journal of Prosthetic Dentistry (Mohamedin and colleagues) found that scanners struggle with toothless ridges because there are few landmarks to stitch images together and the movable tissue at the edges is hard to capture. It concluded that reliable evidence that scans can fully replace conventional impressions for complete dentures is lacking. For that reason, many full dentures are still made from conventional impressions, sometimes combined with digital steps later on.

Comfort favours scanning

Across the studies that asked patients, scanning comes out ahead. A 2026 systematic review in Frontiers in Oral Health (Ramos-Morro and colleagues) found digital impressions were consistently reported as faster and more comfortable in adults, although only a small number of studies measured comfort. A meta-analysis in children (Garcovich and colleagues, International Journal of Paediatric Dentistry, 2026) found less gagging, less breathing difficulty and a strong preference for scanning. If you have a sensitive gag reflex, mention it when you book.

A dentist holding a model of the teeth and explaining it to a patient sitting in a dental chair — A model, printed from a scan or poured from a mould, helps explain what is being planned.

Scans can be compared over time

A digital record can be stored and lined up with a later scan of the same mouth, which makes it easier to see gradual changes such as tooth wear, gum recession or teeth shifting after orthodontics. A plaster model can be kept, but comparing two of them by eye is far less precise.

How we decide at Lumi

Lumi Dental uses a 3D intraoral scanner for most records, and scans can be sent to our in-house lab. Where a case calls for a conventional impression, such as many full dentures, your dentist will explain why. If you have found impressions difficult before, tell us when you book so we can plan around it.

What patients ask

Is a scan more accurate than a mould?

For crowns, short bridges and single implants, current reviews find no meaningful difference. For full-arch implant bridges the research is mixed, and for full dentures conventional impressions are still widely used.

Why would my dentist use a tray instead of a scanner?

Usually because of the type of treatment, most often full dentures, or because bleeding or a deep margin would stop the camera seeing clearly.

Can I ask for a scan?

Yes. It is reasonable to ask which method suits your treatment and why, particularly if you gag easily.

Talk to us about your treatment

If you are planning a crown, a retainer, aligners or implants, our dentists can explain how your records will be taken and what each step involves. See our current deals or read about the general dentistry team at Lumi Dental in Melrose Park.

Sources

Dr James Tran, dentist at Lumi Dental, Melrose Park

Written by Dr James Tran

Dr James Tran (BDent, University of Sydney; Graduate Diploma in Oral Implants) is a general dentist at Lumi Dental in Melrose Park. The team writes these articles to give clear, evidence-based dental information to help you make informed decisions about your care.