A crown that is designed, milled and fitted in a single appointment sounds like a straightforward improvement on the two-visit routine, but the comparison is more nuanced than marketing suggests. Fit, survival and cost all depend on the material and the operator as much as on the technology used ...

A crown that is designed, milled and fitted in a single appointment sounds like a straightforward improvement on the two-visit routine, but the comparison is more nuanced than marketing suggests. Fit, survival and cost all depend on the material and the operator as much as on the technology used to make the crown.
The conventional pathway begins with tooth preparation and an impression, after which a laboratory technician fabricates the crown over one to two weeks. The patient wears a temporary crown in the interim and returns for cementation at the second appointment.
Chairside systems capture the preparation with an intraoral scanner, design the restoration in software and mill it from a ceramic block in the surgery. The crown is glazed or polished and cemented within the same visit, typically in two to three hours.
Marginal gap is the distance between the crown margin and the tooth surface, and it is the most commonly reported laboratory measure of fit. Gaps below roughly 120 micrometres are widely regarded as clinically acceptable.
A systematic review in the Journal of Dentistry in 2014 reported mean marginal gaps of approximately 50 to 100 micrometres for chairside milled crowns and 70 to 150 micrometres for laboratory-fabricated crowns. A study in the Journal of Prosthetic Dentistry in 2019 found no clinically meaningful difference when the same material and the same scanning workflow were used.
A larger marginal gap increases plaque retention and the risk of recurrent decay, which is why fit matters for longevity. Digital scanning also reduces the distortion associated with elastomeric impression materials, which can offset the resolution limits of milling.
A meta-analysis in the Journal of Dentistry in 2014 reported five year survival of approximately 94 to 96 per cent for all-ceramic crowns and ten year survival of roughly 85 to 90 per cent. Ceramic chipping and loss of retention were the most frequent modes of failure.
Lithium disilicate and zirconia offer higher fracture resistance than feldspathic ceramics, and monolithic designs avoid the veneering layer that chips most often. A study in the Journal of Prosthetic Dentistry in 2018 found that monolithic zirconia crowns had lower chipping rates than layered alternatives.
A failed chairside crown can usually be remilled quickly if the original scan is retained, whereas a laboratory crown requires a new impression and another fabrication cycle. This difference affects practical downtime more than it affects survival statistics.
Fee structures vary by region, but the chairside pathway often carries a higher single-visit fee because the practice must recover the cost of the scanner and milling unit. Traditional crowns may cost less per unit while requiring an additional appointment.
Time away from work, travel and the cost of a replacement temporary crown are frequently omitted from comparisons. A study in the Journal of the American Dental Association in 2016 reported that patients valued single-visit treatment highly when the total time burden was considered rather than the fee alone.
Temporaries can loosen, fracture or leak, and each of these events risks sensitivity and pulpal irritation between appointments. A study in Operative Dentistry in 2013 found that temporary crown complications affected a substantial minority of patients over a two week interval.
A single appointment removes the risk of a temporary failure and reduces the total number of injections and visits. It also allows immediate correction of fit or occlusal issues while the patient is still in the chair.
Intraoral scanners capture the preparation, the opposing arch and the occlusion in a few minutes, and the digital file can be re-examined without repeating the appointment. A study in the Journal of Dentistry in 2017 reported that scanner accuracy was equivalent to that of conventional impressions for single units.
Design software proposes a restoration based on the scanned data, and the clinician adjusts the margin, the contact points and the occlusal surface. A study in the International Journal of Prosthodontics in 2018 found that operator experience influenced the final fit more than the software version did.
Ceramic blocks are milled to a tolerance of a few tens of micrometres and then crystallised, stained and polished or glazed. A study in Dental Materials in 2016 reported that the finishing protocol influenced surface roughness and bacterial adhesion more than the milling process itself.
Chairside crowns suit patients with limited availability, those who travel long distances, and cases where a temporary would be difficult to manage. They also suit anterior restorations where immediate aesthetics matter.
Laboratory fabrication offers greater flexibility for complex shades, extended spans and cases requiring a specific technician's artistry. A study in the International Journal of Prosthodontics in 2017 noted that highly characterised multi-unit cases were often better served by a laboratory workflow.
The crown margin is the site where recurrent decay begins, so cleaning should include the junction between the crown and the tooth. Interdental brushes or floss should be used daily, and a study in the Journal of Clinical Periodontology in 2015 confirmed that interdental cleaning reduces marginal inflammation.
Patients should have the occlusion checked at review, because a crown that sits slightly high concentrates load and can cause both discomfort and material failure. A powered brush such as the BrushO with a pressure sensor helps protect the margin and the adjacent gingiva during daily cleaning, where excess force is most likely to cause recession.
Patients should ask which material will be used, whether the practice mills restorations on site and what the replacement policy is if the crown fails within a defined period. A study in the Journal of the American Dental Association in 2018 found that patients who discussed material options reported higher satisfaction with the final restoration.
Questions about cleaning around the margin, expected sensitivity and review intervals help patients maintain the restoration in the years that follow. Clear aftercare instructions reduce avoidable returns and extend the service life of the crown.
Same-day and traditional crowns achieve comparable marginal fit and survival when the same material and digital workflows are used, so the choice depends mainly on convenience, complexity and cost structure. Chairside milling excels for straightforward single units and time-poor patients, while laboratory fabrication retains advantages for complex, highly aesthetic cases.
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Sep 28
Sep 28

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