Guided Implant Surgery

Question 1

Implant Placement: Pitfalls

Answer 1

• Patient movement while drilling
• Limited surgery time due to LA
• restricted visual field
• mental transfer of 2D x-ray to 3D
• Esthetics
• Biomechanics
• Functional Constraints of prosthesis

Question 2

Guided Implant Surgery Involves:

Answer 2

• CBCT
• extraoral and intraoral scanners
• rapid prototyping and 3D printing
• Guided Surgery

Question 3

Guided Implant Surgery: General Info

Answer 3

• Developed in Mid 1990s
• CBCT allowed:
  
  • volumetric jaw bone imaging
    
    • low cost and radiation
  • Large amount of info pre-op
    
    • available bone volume and quality
    • location of anatomy and pathology
• Completely planned pre-op

Question 4

Guided Implant Surgery: Workflow

Answer 4

Exam→Planning→Execution

Question 5

Guided Implant Surgery: Examination & Limits

Answer 5

• requires CBCT
• used with flap and flapless approach
  
  • No Flap=No Graft
• Edentulous vs partially edentulous patients
  
  • Edentulous:
    
    • 1 Scan System:
      
      • create radiopaque resin replica of pts prosthesis
    • 2 Scan System: (Dual scan w/Fiducial Markers)
      
      • 1st-with prosthesis markers & Bite registration
      • 2nd- with prosthesis markers
  • Partial Edentulous:
    
    • Virtual Computerized Prosthetic Wax-up
    • Scan analogue or cast
    • data superimposed on CBCT
• Limits:
  
  • Prosthetic Thickness for correct segmentation
  • artifacts
    
    • Motion-during CBCT
    • Metal
  • Correct tooth setup
  • Incorrect
    
    • fiducial markers (Double-scan)
    • Matching of scan and CBCT

Question 6

Guided Implant Surgery: Planning & Limits

Answer 6

• 3rd party software
  
  • plan implant placement and fixation pins/screws
• Digital info→ produce stent with analogue method or CAM rapid prototyping (Milling or 3D printing)
• Limits:
  
  • not enough inter arch space
  • Unavailable Drill lengths (Drills to long)
  • Thin guide material→ Break
  • Printing Angulation Error (0.25-1.5°)

Question 7

Guided Implant Surgery: Execution & Limits

Answer 7

• Try guide in mouth before surgery
  
  • bite index, mini-screws, fixation pins and temp implants can be used
• punch technique-Flapless approach
  
  • Drill Keys-Drills w/physical or visual stop
• Accuracy:
• Limits:
  
  • Rotated guide→Inaccurate implant position
    
    • Fix with bite index
    • check Occlusal of guide
  • Local anesthesia changes mucosa
  • Depth (Most significant error)
    
    • Debris within osteotomy
    • Deformed Guide
    • Low gray values

Question 8

Accuracy

Answer 8

• difference b/w the:
  
  • planned (what you want) and
  • inserted (what you actually got) implant placement
• 4 parameters (Deviation of the __) (Van Ash/Tahm)
  
  • entry point (0.99/0.9 mm)
  • Apex (1.24/1.39 mm)
  • Long Axis (3.81 /3.5°)
  • Depth
• Guide vs no guide:
  
  • Significant Deviation
• Guides: Tooth supported> Mucosa supported> Bone supported

Question 9

What are the main steps to plan a guided surgery?

Answer 9

• CBCT
• extra/intraoral scanners
• 3D printing

Question 10

What are the indications of guided surgery?

Answer 10

• Limited Mouth Opening
• No flap needed
• Have Time to plan
• Whenever you can do it

Question 11

What are the limitations of guided surgery?

Answer 11

• Correct and accurate images
• Insufficient arch space
• cumulative deviation
• mucosal changes
• deviation of depth
• breaking of guide