CAD Design — Project Preview Before Production

One of the most common reasons for complaints about prosthetic work is the discrepancy between the clinician's expectations and the final product. The error doesn't lie in the material or the milling machine — it lies in the fact that the design wasn't approved before production. At deltalabs., the CAD design is always sent to the clinician for approval before machining begins.

What is a CAD Preview?

A CAD preview (digital wax-up) is a three-dimensional model of the future restoration shown to the clinician before milling or printing begins. In practice, these are renderings from several perspectives: mesial, distal, occlusal, and labial. The clinician sees the exact shape, contours, and relation to adjacent teeth — not a sketch, but a real geometric model from which the restoration will be fabricated. Corrections reported at this stage cost minutes. Corrections after production cost days.

When and What We Send for Approval

Standard at deltalabs.:

Approval deadline: 48 hours. If we do not receive a response within this time, the project is automatically approved, and we proceed with production.

What We Evaluate During the CAD Stage

The CAD technician checks the design for four parameters: Preparation Shape. Does the extent of the preparation allow for adequate material thickness? For zirconia, the minimum is 0.5 mm for copings; for zirconia veneers, 0.3 mm. If the preparation is too scant — we inform before production. Occlusal Space. How much space is there between the prepared tooth and the opposing arch? The minimum space for a monolithic zirconia crown is 1.0–1.5 mm. Less than that — production is possible, but quality may require compromise. Proximal Contact. The contact point with adjacent teeth. The technician designs it based on scanner data. If adjacent teeth were not scanned, the contact is designed based on anatomy and may require adjustment upon delivery. Contour and Anatomy. Does the design fit the surrounding dentition? Is the cervical line correct? Is the inclination angle consistent with adjacent teeth?

Example from Practice

A clinician submitted a scan for a 3-unit posterior bridge. The CAD technician detected in the preview: insufficient space between the pontic and the gingival ridge — a risk of plaque accumulation and hygiene issues. Information sent to the clinician before production: proposal to change the pontic contour from saddle-shaped to hygienic-convex. The change took 4 hours. The restoration was sent without problems. Without the preview stage: a saddle-shaped pontic bridge, a hygiene problem after several months, a complaint, and redesign.