Technology notice: CAD/CAM describes a design and manufacturing workflow, not one material or quality level. Clinical examination, preparation, material selection, bonding and quality control remain essential.

What is CAD/CAM dentistry?

CAD/CAM means computer-aided design and computer-aided manufacturing. Dental anatomy is digitised with an intraoral scan or laboratory scanner, a restoration is designed in software and then manufactured by milling or another controlled process. The workflow is used for crowns, inlays, onlays, veneers, bridges, dentures, implant components, guides and models.

“Computer made” does not mean untouched by humans. The dentist or technician defines margins, insertion path, contacts, occlusion, thickness and material. The manufactured restoration then requires inspection, finishing and sometimes staining, crystallisation, sintering or veneering.

The digital workflow

Diagnosis, preparation and tissue management.
Digital or conventional impression and bite record.
Design using material-specific parameters.
Nesting within a block, disc or production batch.
Milling, printing or centralised manufacturing.
Post-processing, finishing and quality checks.
Clinical try-in, adjustment and bonding or cementation.

Chairside and laboratory CAD/CAM

Chairside systems can scan, design and mill selected restorations in one visit. This may avoid a provisional and second anaesthetic, but speed should not compress diagnosis, crystallisation, adhesive isolation or adjustment. Complex shade matching and extensive rehabilitation may benefit from laboratory collaboration.

Laboratory systems offer broader material and equipment choices, technician characterisation and batch manufacturing. A clinic can also scan chairside and transmit the file to a laboratory, creating a hybrid workflow.

CAD/CAM materials

Blocks and discs include feldspathic ceramic, leucite ceramic, lithium disilicate, zirconia, hybrid ceramic, composite, PMMA, PEEK and metals. Each requires different minimum thickness, bur strategy, post-processing and bonding. Selecting from a software library does not make materials interchangeable.

Zirconia typically requires sintering after milling. Some lithium-disilicate blocks require crystallisation firing. PMMA may serve as a provisional rather than a definitive ceramic substitute. Material identity and lot information should remain traceable.

Accuracy and fit

Fit is affected by every step: scan quality, margin detection, software settings, milling resolution, bur wear, post-processing and cement space. A digitally smooth margin can still be based on an incorrect clinical scan. The restoration must be evaluated on the tooth rather than accepted because software shows no collision.

Internal adaptation and marginal fit are not the only outcomes. Contact strength, occlusion, emergence profile, cleansability, aesthetics and biological response all matter.

Subtractive and additive manufacturing

Milling is subtractive: burs remove material from an industrial block or disc. It offers established workflows but wastes unused stock and has geometric limits related to bur diameter. Additive manufacturing builds an object layer by layer and can create complex shapes with less stock waste, but resin chemistry, orientation, support removal and post-curing strongly influence properties.

A printed object is not automatically equivalent to a milled one with the same generic material name. Regulatory indication and validated processing must be checked.

Same-day crowns

A same-day crown can be convenient when the tooth, material and aesthetic demands suit the workflow. The preparation is scanned, designed and milled, then tried in and bonded or cemented. Some cases still require laboratory work, staged tissue healing or additional characterisation. “Same day” should never imply skipping necessary endodontic, periodontal or caries assessment.

Potential advantages

Rapid transfer and reproducible digital records.
Industrial material blanks with documented processing.
Visual design tools for thickness and contacts.
Single-visit options for selected restorations.
Ability to duplicate or modify archived designs.

Limitations and failure points

Deep or contaminated margins can be scanned incorrectly.
Automatic proposals may create poor anatomy or over-contour.
Thin areas can fracture during milling or service.
Incorrect sintering or crystallisation changes properties.
File and library incompatibility can disrupt continuity.
Machine calibration, bur wear and maintenance affect output.

Clinical survival

Systematic reviews report favourable outcomes for many CAD/CAM ceramic restorations, but results are heterogeneous and depend on material, restoration type and follow-up. CAD/CAM is not itself the reason a restoration survives. Tooth condition, preparation, bonding, occlusion, hygiene and maintenance remain major determinants.

Data governance and traceability

The record should identify the scan, design version, material, manufacturer, lot or blank, machine and post-processing where relevant. Open export formats reduce dependence on one vendor, although some metadata can be lost. Patient data and facial scans require secure transfer and controlled access.

Design parameters that matter

Software settings include cement space, margin offset, minimum thickness, connector area, milling compensation and contact strength. Default values are starting points, not universal biological truths. Increasing cement space may improve seating but can reduce support or change marginal behaviour; enforcing minimum thickness can create an over-contoured crown if preparation space is inadequate.

Virtual articulators and automated occlusion tools approximate movement from the records supplied. A static bite scan may not reproduce excursive contacts, muscle guidance or changes when anaesthesia wears off. Clinical adjustment remains necessary.

Try-in and delivery

Before cementation, the restoration should be checked for complete seating, marginal adaptation, proximal contacts, occlusion, shade and surface integrity. Excessive internal adjustment can create defects or thin the restoration. Ceramic surfaces altered chairside require material-specific polishing; glaze alone is not a substitute for a smooth adjusted surface.

Bonding protocols depend on the substrate and restorative material. Glass ceramics, zirconia, composite blocks and metals require different cleaning, primers and cements. The convenience of one-visit production does not justify a generic adhesive protocol.

Remakes and archived designs

A stored design can speed replacement, but the mouth may have changed through tooth movement, recession, wear or tissue healing. A duplicate should not be manufactured without checking current records. The original failure also needs diagnosis: duplicating a fractured design can duplicate its weak point.

Environmental claims

Digital workflows can reduce physical impressions and shipping, while milling produces unused stock and relies on burs, furnaces and energy. Printing uses resins, supports and cleaning materials. Environmental benefit depends on the complete workflow and remake rate; “paperless” or “digital” alone is not proof of lower impact.

Questions to ask

Which material and production route will be used?
Is a same-day workflow clinically appropriate?
Who designs and quality-checks the restoration?
What firing, sintering or post-curing is required?
Can the design and material details be retained in my record?
How will fit, bite and cleansability be verified?

Evidence summary

CAD/CAM can make restorative workflows efficient and reproducible, but it is a chain whose accuracy is limited by its weakest step. Good outcomes require correct indication, precise clinical records, material-specific production and final human verification.

Sources

Prepared as general educational information. Clinical and laboratory teams must follow the validated workflow for the exact material and device.

CAD/CAM Dentistry