exocad Design Tips: Occlusion, Contacts, and Emergence Profile

exocad is the most widely used dental CAD software in the independent lab market, and for good reason — it's flexible, extensively customizable, and the library ecosystem is mature. But flexibility also means there are a lot of ways to produce suboptimal designs. This article focuses on three areas where technicians most commonly need to refine their approach: occlusal contact design, proximal contact management, and emergence profile geometry.

Occlusal Contact Design in exocad

Understand the Biogeneric vs. Proposal Tools

exocad generates initial crown geometry using either the biogeneric algorithm (derives shape from adjacent and opposing teeth in the scan) or a library tooth proposal. Both are starting points — they are never final without review.

The biogeneric tool is excellent at generating anatomically plausible crowns quickly, but it will occasionally produce incorrect occlusal contacts — particularly in edentulous segments where the opposing arch data is incomplete, or when the bite registration doesn't fully close. Always verify occlusion in the 3D view after initial generation before moving to fine adjustment.

Using the Occlusion Visualization

In exocad's design window, use the occlusion color map (View → Occlusion or the colored contact display toggle, depending on version). This shows contact proximity using a heat map — red/orange for close contacts or interferences, blue/green for clearance. Best practice:

• Posterior crowns in centric: target uniform light green contacts on cusp tips and marginal ridges. Avoid red contacts at cusp tips or fossa that would represent a heavy or premature contact.
• Check lateral excursion contacts using the articulation simulation if your exocad version includes it (DentalCAD 3.0+ includes virtual articulator integration)
• Do not design anterior restorations with heavy lingual incisal contacts unless specifically requested — this is a common source of sensitivity and fracture

Adjusting Occlusal Contacts

If the auto-generated design has unacceptable contacts, use the Free Form tool to sculpt the surface. Tips:

• Use "Pull" mode with a large brush radius (5–8 mm) to make global adjustments to fossa depth without creating abrupt transitions
• Use a small radius (1–2 mm) and "Smooth" mode for localized contact removal
• When removing a contact by thinning a cusp, check the minimum thickness display to ensure you're not violating the minimum wall thickness for your material
• After Free Form adjustments, re-check the full occlusal color map — adjusting one area can shift contacts elsewhere

Proximal Contact Management

Contact Strength Settings

exocad controls proximal contact strength through the Contact Strength slider in the Design Parameters or Dental Parameters panel. The slider runs from 0 (no contact) to a positive value (tight contact). Clinically, you want contacts that hold shimstock with light resistance.

Recommended starting values (adjust for your specific lab workflow and articulator accuracy):

• Posterior crown contacts: +50 to +80 µm contact strength
• Anterior crown contacts: +30 to +50 µm
• Bridge span contacts (mesial/distal of the bridge): +80 to +100 µm (bridges tend to seat with slightly more resistance, so design contacts slightly stronger to compensate)

These values assume a well-calibrated scanner and articulated model. If your clinician is consistently reporting open contacts or contacts that require adjustment, adjust the contact strength setting up or down accordingly and document the change.

Contact Location

Where the contact touches matters as much as how strong it is. In exocad, visually verify the contact point location in the 3D view:

• Posterior contacts should be in the occlusal-middle third of the proximal surface — not at the cervical third (causes food packing and gingival pressure) and not at the cusp tip (premature and difficult to adjust)
• Anterior contacts should be centered faciolingually and in the middle third of the proximal surface
• Implant crowns: avoid over-contoured proximal contacts that push against the adjacent tooth — this is the #1 cause of adjacent tooth mobility reports after implant crown delivery

Emergence Profile Design

For Crown-on-Tooth Preparations

Emergence profile for a tooth-supported crown is relatively straightforward — the emergence should mimic the contour of the pre-existing tooth. In exocad, check the cervical area of the design against the scan by toggling the underlying tissue scan visibility. The restoration should not over-contour or undercontour beyond the adjacent tooth profile unless specific anatomy correction is requested.

Common mistakes:

• Overcontouring the facial buccal surface to gain shade match — this creates a "ledge" that traps plaque and causes gingival inflammation
• Designing a flat or concave emergence at the gingival margin — should be slightly convex for tissue health

For Implant Restorations

Implant emergence profile design has clinical consequences that go beyond esthetics. The emergence profile shapes the peri-implant tissue — both its volume and health.

Emergence Angle Principles

Research consistently shows that narrow emergence angles (<30° from the implant axis) support better peri-implant tissue health than wide, flared profiles. In practice:

• Start with a concave or straight profile directly above the implant platform
• Transition to the desired crown anatomy over the height of the soft tissue cuff
• Avoid convex emergence at the subgingival level — this compresses tissue and is associated with bone loss over time
• For tissue-level implants (Straumann TL), the emergence profile begins above the roughened implant collar — design convexity above this point only

Designing Emergence in exocad

1. In the implant crown workflow, use the "Tissue Margin" tool to accurately place the gingival margin from the scan data
2. Increase the display of the subgingival area by adjusting the transparency of the model
3. Use Free Form to shape the subgingival portion — start concave or straight, then transition outward at or above the gingival crest
4. Compare to contralateral anatomy where available
5. For single implants in esthetic zones, a provisional restoration shaped by the clinician before final impressions gives you a template — request a scan of the shaped provisional if possible

Minimum Thickness Checks Before Export

Before exporting any design for milling, run the minimum thickness check in exocad (Analysis → Minimum Thickness or the dedicated button depending on version). Set the threshold to the minimum for your material:

• Zirconia 3Y: 0.4 mm (axial), 0.5 mm (occlusal)
• Zirconia 4Y/5Y: 0.5 mm (axial), 0.8 mm (occlusal)
• Lithium disilicate (pre-crystal CAD): 0.5 mm standard
• PMMA/composite: 0.5–0.8 mm depending on brand

Any area highlighted as below minimum must be addressed in the design before milling. Never rely on "it'll probably be okay" — thin areas that the software flags are potential fracture sites that will fail in service.

Design Workflow Efficiency Tips

• Save custom parameter presets: For each material and restoration type you commonly design, save a named parameter preset in exocad. This prevents having to reset contact strength, cement gap, and minimum thickness every time.
• Use the Undo history aggressively: If a Free Form adjustment goes wrong, Ctrl+Z multiple times — the undo history in exocad is deep enough to back out most mistakes.
• Batch similar cases: Design all the same restoration type (e.g., all molar crowns) in a session rather than switching back and forth — context switching burns time.
• Library maintenance: Keep your exocad implant and tooth libraries updated. Outdated library entries are a silent source of fit errors that can be hard to diagnose.