A diagnostic wax-up is the design of the future tooth shape, in wax or digital, that you use for an intraoral mock-up and agree with the patient before any preparation. For multi-unit esthetic cases, changes in tooth length or proportion, and bite raising.
In multi-unit esthetic cases, the key question is not “is the restoration beautiful” but “is it what the patient agreed to”. A wax-up, in wax or digital, is the visual agreement between dentist, patient and lab. You use the wax-up model to make an intraoral mock-up; once the patient has seen and approved the shape, length and smile line, our job is to reproduce that design faithfully.
A wax-up is most useful for multiple anterior veneers or crowns, changes in tooth length or proportion, bite raising or vertical dimension changes, and prosthetically driven implant placement (a virtual wax-up is used when planning a surgical guide).
In our lab, the approved wax-up is scanned and becomes the reference for the whole final design. Veneers or crowns are designed from the wax-up template, adjusting only minimum thickness and margins to the actual preparations, and the design file is superimposed on the wax-up file to check deviation before milling. Quality control then comes down to comparing the restoration with the wax-up, and chair time drops because the shape was approved in advance.
We do not change an approved wax-up on our own. If it needs adjusting, please be specific, for example “keep the shape, shorten the incisal edges by 0.5 mm”. Preparing through the mock-up also keeps restoration thickness even, instead of compensating by making the restoration thicker.
Diagnostic wax-ups are scheduled case by case, depending on the number of units and the extent of the change. For multi-unit veneer cases, please send the approved wax-up together with the post-preparation scan so the restorations follow the design.
To discuss a specific case, contact our team or start through the ordering process.
Written for dentists and technicians. Khai Nguyen Dental Lab works to clinical prescription only and does not sell directly to patients.
Both give the same thing: a target tooth form that you and the patient approve before any preparation. They differ in what we need from you, what you receive, and how changes are made.
| Aspect | Analog (wax) | Digital |
|---|---|---|
| Input | Impressions or models and a bite registration | Scans of both arches and the bite (STL, PLY, DCM) |
| You receive | A model with the wax-up | The design file, review screenshots, and a printed model if you need a mock-up |
| Changes | Wax added or carved on the model | Edited in the file and can be overlaid on the previous version |
Per our brochure, a digital wax-up design takes 12 hours from receipt of complete data, with a 2-hour express option (see our CAD design service). If you need a printed model, note it on the prescription; we confirm fabrication and shipping time when we accept the case.
You take a silicone key from the wax-up model, load it with provisional material and seat it on the unprepared teeth. The patient sees shape, length and smile line in the mouth and in the face. Gürel describes the sequence of mock-up, wax-up, aesthetic pre-evaluative temporaries (APT) and silicone index as a way for patients to assess esthetics, phonetics and function, and as the communication channel between dentist, patient and ceramist.
A mock-up is not an exact copy of the wax-up. In an in vitro study on 30 typodont maxillary central incisors, a uniform 0.3 mm digital wax-up was transferred to resin trial restorations through a silicone index made on printed casts; the trial restorations were 0.20 ± 0.14 mm thicker than the wax-up, mostly at the cervical area (Luo et al., 2024). Check and clean cervical excess before the patient approves the mock-up or you prepare through it.
When the wax-up is additive, you can prepare through the mock-up so that depth is measured from the target form rather than from the existing tooth. Magne and Belser (2004) describe this mock-up-driven approach for porcelain laminates and state that it allows more enamel to be preserved. In Gürel et al. (2012), 66 patients received 580 veneers prepared with an additive mock-up and the APT technique and were followed for 12 years: over 80% of preparations stayed in enamel; 42 veneers failed, but where preparations were limited to enamel the failure rate from debonding and microleakage was 0%. Coachman et al. (2014) add calculated parameters to the mock-up to show how much to reduce and where.
After preparation, a silicone key sectioned horizontally or sagittally shows the remaining space against the wax-up. Detailed principles are in minimally invasive preparation for crowns and veneers. When ordering, please state whether you need a mock-up key, a reduction key, or both.
The same silicone key can be used to make the provisionals after preparation, so the patient wears the approved form while the definitive restorations are made. This is the real-life test: eating, speaking and seeing the new form. If anything changes during that period (incisal edge, length, smile line), send intraoral photos of the provisionals with notes, or a scan of them, so we update the wax-up before making the definitive restorations rather than following the old version.
A wax-up is set from the face, not only from the model. We need a frontal smile photo, a lips-at-rest photo showing incisal display, and retracted intraoral views. The minimum set, how to shoot on-axis and the three errors that ruin a set are in dental photography for the dental laboratory.
Sources: Gürel G. Porcelain laminate veneers: minimal tooth preparation by design. Dent Clin North Am. 2007;51(2):419-431; Luo T, Li J, Xie C, Yu H. Accuracy of three digital waxing-guided trial restoration protocols for controlling the depths of tooth preparation for ceramic veneers. J Prosthet Dent. 2024;131(1):56-63; Magne P, Belser UC. Novel porcelain laminate preparation approach driven by a diagnostic mock-up. J Esthet Restor Dent. 2004;16(1):7-16; Gürel G et al. Clinical performance of porcelain laminate veneers: outcomes of the aesthetic pre-evaluative temporary (APT) technique. Int J Periodontics Restorative Dent. 2012;32(6):625-635; Coachman C et al. The influence of tooth color on preparation design for laminate veneers from a minimally invasive perspective. Int J Periodontics Restorative Dent. 2014;34(4):453-459.
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