Managing Dental Laboratory Coordination

Documents to Request

• Completed lab prescription (ADA-compliant Rx form)
• Impressions or intraoral scan files (STL/PLY with bite registration)
• Shade photographs (with shade tab in photo, 90-degree angle, corrected white balance)
• Opposing arch impression or scan
• Face-bow record (if full-arch or complex occlusion)
• Pre-operative photographs showing tooth position, gingival contour, and existing restorations
• Implant component documentation (manufacturer lot number, platform specifications)
• Any prior lab work for this patient (for consistency reference)

Step 1: Lab Prescription Writing

Required Prescription Elements (FDA 21 CFR 807 / ADA Standard)

Step 2: Shade Selection and Communication

Shade Selection Protocol

1. Remove bright-colored items from the patient's field (lipstick, colorful bibs)
2. Select shade at the beginning of the appointment before tooth dehydration
3. Use daylight-corrected lighting (5500K) or a calibrated shade-matching light
4. Hold shade tab at the same plane as the tooth; evaluate at arm's length
5. Determine value (lightness/darkness) first — this is the most critical dimension
6. Map cervical, body, and incisal thirds separately; most teeth are not uniform
7. Photograph with shade tab adjacent to the prepared and adjacent teeth using:
   • Consistent white balance (custom or daylight preset)
   • Cross-polarized filter if available (eliminates specular reflection)
   • Gray card in frame for post-processing reference

Digital Shade Devices

Communicating Shade to Lab

• Always send photographs even when using a spectrophotometer
• Include the shade tab in the photo for lab-side verification
• Note any characterization: translucency, hypocalcification spots, crack lines, halo effects
• For anterior cases, send full-face smile photo for proportional and color context

Step 3: Material Selection Decision Framework

Fixed Restoration Material Guide

Step 4: Receiving Inspection and Quality Assessment

Incoming Lab Work Checklist

1. Visual inspection: Check for chips, cracks, voids, or rough surfaces under magnification
2. Shade verification: Compare to shade tab under calibrated light; check cervical, body, incisal zones
3. Marginal fit: Seat on die or model; margin gap should be ≤ 120 µm (ADA-accepted threshold)
4. Contact evaluation: Assess mesial and distal contacts with shimstock (hold, not excessive)
5. Occlusal check: Articulate on model; verify centric contacts and excursive clearance
6. Internal fit: Check internal surface for positive seat; no interfering nodules
7. Pontic design: Verify tissue surface matches prescription (ovate, ridge lap, etc.)
8. Material confirmation: Verify lab invoice matches prescribed material
9. Implant components: Confirm abutment type, torque specifications, and anti-rotational feature match prescription

Rejection Criteria

• Visible crack or chip that compromises structural integrity
• Shade mismatch detectable under standard lighting
• Marginal gap exceeding 200 µm at any point
• Open or excessive contacts that deviate from prescription
• Wrong material fabricated
• Implant component mismatch (wrong platform, connection, or angulation)

Step 5: Lab Performance Tracking

Metrics to Track Per Lab

Quarterly Lab Review

• Compile metrics from case log
• Identify top remake categories (shade, fit, material, design)
• Schedule lab technician visit for complex anterior and implant cases
• Review any patient complaints traceable to lab quality issues

Step 6: Digital Workflow Integration

Intraoral Scan File Management

Digital Design Review (CAD Preview)

1. Request a CAD preview from the lab before milling or printing for complex cases
2. Review contour, contact design, occlusal anatomy, and emergence profile on screen
3. Approve or request modifications BEFORE fabrication — changes after milling require a remake
4. Digital design approval should be documented in the case log with the date and approving clinician

3D Printing in Prosthodontics

Checkpoint B: Post-Delivery Alignment (Mandatory)

1. Did the restoration seat passively with acceptable marginal fit?
2. Does the shade match adjacent teeth under multiple lighting conditions?
3. Are contacts and occlusion confirmed with shimstock and articulating paper?
4. Was the patient satisfied with esthetics and comfort at the delivery appointment?
5. Has the case been logged in the lab performance tracking system?

Quality Audit

Guidelines

• The lab prescription is a legal medical device order — never send impressions without a signed, complete prescription
• Shade photographs are mandatory for all anterior restorations and recommended for premolars
• Specify material by full name and type; "zirconia" alone is insufficient because 3Y-TZP, 4Y-TZP, and 5Y-TZP have different translucency and strength profiles
• Use digital impressions (intraoral scanning) when available — they eliminate pouring errors and allow instant quality checks at chairside
• Request a try-in stage (bisque bake for PFM, unglazed for all-ceramic) for anterior esthetics cases before final glazing
• Never accept a remake without documenting the defect and communicating the issue to the lab — silent acceptance perpetuates quality problems
• Maintain a case log that links each lab case to the patient record, prescription, delivery date, and outcome
• For implant cases, always send the implant analog, scan body, or digital library file — never expect the lab to guess the implant platform