Common Scanning Errors and How to Fix Them
Intraoral scanning errors waste chair time and delay case delivery. Learn to identify and correct the most common scanning mistakes before submitting to your lab.
Why Scan Quality Matters
2-3 Days Lost
Average delay from rescans
$150-300
Cost of remake from bad scan
Patient Frustration
Additional appointment needed
Error 1: Incomplete Margin Capture
Problem
Preparation margins not fully captured, especially on lingual/palatal aspects or subgingival areas.
Visual Indicators:
- • Gray/fuzzy areas at margin
- • Mesh "holes" in gingival area
- • Discontinuous margin line
- • Scanner freezes during capture
Solution
Before Scanning:
- ✓ Use retraction cord (double cord technique)
- ✓ Apply hemostatic agent if bleeding
- ✓ Dry tooth completely with air syringe
- ✓ Check prep with explorer for sharp lines
During Scanning:
- ✓ Angle scanner tip to "see" subgingival
- ✓ Make 3-4 passes around prep margin
- ✓ Scan from occlusal down to margin
- ✓ Verify margin capture before moving on
Error 2: Motion Artifacts & Blurring
Problem
Scanner moved too quickly or patient moved during capture, causing distorted geometry.
Causes:
- • Scanner tip moved > 2mm/second
- • Patient swallowed or gagged
- • Inadequate patient stabilization
- • Saliva pooling causing scanner confusion
Solution
Technique Adjustments:
- ✓ Move scanner in slow, steady motion
- ✓ Pause briefly when scanner tone changes
- ✓ Use bite block for patient stabilization
- ✓ Give patient "swallow breaks" every 30 sec
Speed Guidelines by Scanner:
- • iTero: ~1 tooth per 3-4 seconds
- • 3Shape: Continuous sweep, 1mm/sec
- • Cerec: Faster OK, but watch for gaps
Error 3: Missing Opposing Arch Data
Problem
Opposing arch scan incomplete, especially distal regions, making occlusal contact design impossible.
Why It Happens:
- • Operator assumes "it's not the prep, so less important"
- • Difficult to scan (limited opening, gag reflex)
- • Scanner loses tracking in posterior
- • Saliva accumulation not managed
Critical Areas:
- ✓ At least 1 tooth mesial to prep
- ✓ At least 2 teeth distal to prep
- ✓ Full occlusal surface of opposing tooth
- ✓ Lingual/palatal cusp tips for clearance
Error 4: Inaccurate Bite Registration
Digital bite registration is the most common cause of occlusal interferences and high contacts.
Common Mistakes
❌ Patient Not in CR
Patient closes into habitual occlusion, not centric relation
❌ Insufficient Contact Area
Only scanning buccal cusps, missing lingual/palatal
❌ Soft Tissue in Way
Cheek or tongue interfering with closure
❌ Motion During Capture
Patient opens slightly or shifts during bite scan
Correct Bite Registration Protocol
- 1.Have patient practice closing into CR (chin point method or bimanual manipulation)
- 2.Dry both arches thoroughly before bite scan
- 3.Retract cheeks/lips away from scan area
- 4.Instruct: "Close gently into the back teeth and hold still"
- 5.Scan from buccal around to lingual on both sides
- 6.Verify scanner shows green "accepted" indication
Error 5: Powder Application Issues
For scanners requiring powder (older CEREC, some 3Shape models):
Too Little Powder
- • Shiny spots where tooth reflects light
- • Scanner can't acquire surface
- • Gaps in mesh data
Fix:
Apply additional thin layer, hold spray 10cm away
Too Much Powder
- • Visible clumps on tooth surface
- • Rounded/softened margin detail
- • Inaccurate dimensions (+100 microns)
Fix:
Blow off excess with air syringe, reapply light coat
Pre-Submission Quality Checklist
Preparation Arch
- ☐Complete margin visible 360° around prep
- ☐No gray/fuzzy areas on prep or adjacent teeth
- ☐At least 2 teeth mesial and distal captured
- ☐Tissue not overhanging margin
- ☐No motion artifacts or distortions
Opposing & Bite
- ☐Opposing arch includes 2+ teeth past prep
- ☐Occlusal surfaces fully captured (not flat/smooth)
- ☐Bite registration shows green "accepted"
- ☐Contacts visible in bite scan (not gaps)
- ☐Buccal and lingual cusps included in bite
Lab Quality Review
Our technicians inspect every scan within 2 hours of submission. You'll receive immediate notification if rescanning is needed before we start fabrication.
Margin Completeness
Dimensional Accuracy
Occlusal Clearance
Need Scanner Training?
Schedule a free 1-on-1 training session with our scanning specialist