Radiographic Assessment Options For Dental Implants Flashcards
Role of imaging
Pre/peri/post-operative roles
Preoperative modalities
Roles/ technologies / assessment
Radiographic templates (ITI Video)
Prescriptive/ indicative
Why is cross sectional CBCT imaging unique in contrast to tomography and multi-slice CT imaging
It is a dynamic and interactive process
Can be used to direct the placement of implant fixtures - indirectly by construction of restrictive surgical guides or directly by the use of image guided navigation
Preoperative roles
Determine bone volume
Prosthodonticall/Surgical driven site assessment
Bone quality
Width/height
Orientation
Correlation
Anatomic consisderations
Proximity to vital structures
What is the quality of bone within the alveolar ridge?
Cortical bone/trabecular bone pattern
Bone resorption topography
What vital structures encroach on the residual alveolar ridge ?
Maxilla - sinus, nasopalatine canal
Mandible- mental foramen, inferior alveolar canal
Consider prosthetic space requirements
Inter-coronal space
Oro-facial space
Inter-radicular space
Inter-occlusal space
Fixed inter occlusal space
Allow for soft tissue, abutment, metal, restorative material, +/- cement
Anterior - 10-12mm
Posterior - 8-9 mm
Removable inter occlusal space
Allow for soft tissue, adequate abutment and prosthetic thickness
Bar - greater than or equal to 15 mm (15 -17 mm)
Attachment - greater than or equal to 7mm (10-12mm)
A guide, derived from the diagnostic ___________, used to assist in the preparation for and the placement of implants. It dictates drilling _________ and angulation.
Wax-up, position
Post operative objectives
- Monitor osseointegration - bone to implant interface, marginal bone level stability
- Immediate or delayed review of implant position
- Establish osseointegration failure
- Prior to implant retrieval
- Graft success
Monitoring ossoeintegration : Radiographic success criteria
Subjective (patient satisfaction)
Prosthetic criteria
Peri-implant soft tissue criteria
Implant - absence of pain, mobility, Radiographic
Implant radiography
< 1.5 mm crestal bone loss at 1 yr
<0.2 mm annual crestal bone loss after 1st year
Absence of peri-implant radiolucency
Bone to implant interface
0.2 mm pa limitation
Non integration = continuous RL
Overshoot artifact
Apical RL = drill/mental foramen
Marginal bone level stability
Initial angular defect after loading
Subsequent bone loss
Subsequent bone loss type
Branemark - 0.05 mm/yr
Roughened surface - 0.4-0.5 mm/yr
Subsequent bone loss load
0.05-0.1 mm /yr
2 stage - 0.5-1mm 1st year
1 stage - 0.6mm (Mn) 1.1 mm (Mx)
Radiographic grid ruler Half units of interthread distance (thread pitch)
Branemark 0.6 thread pitch, accuracy = 0.3mm
Digital intraoral radiography
Highest resolution of all modalities
10% magnification
Long cone paralleling technique mandatory
Cost and utility
Rigid = minimizes distortion
Measurement algorithm = reduces intra/inter observer realizability
Digital intraoral radiography advantages
Identification of local anatomy
Assessment of mesio-distal orientation- relative root angulations
Measurement accuracy = good MD, excellent A-C (vertical) using standardized (callibration) techniques
Digital intraoral radiography disadvantage
No bucco-lingual information
Pano advantages
Available
Simple to perform
Cheap
Excellent screening of the status of the dentition
Pano linear measurement calibration
-Digital image calibration with RO balls provides clinically acceptable vertical measurement accuracy (95% confidence interval approx 10%)
-2mm safety zone
-Linear opaque markers assist in determining trajectory for measurement
Pano measurements and implant criteria
Interarch
Space between adjacent teeth
Space between roots
Residual ridge
Pano interarch (ridge to occlusal platform) distance
6.5 mm minimum
Pano restorative space (between crowns)
6.5 mm minimum
Pano Me-Di bone volume (between roots)
1.5 mm from root to implant on either side
Implant diameter plus 3mm (min 6.5 mm)
Pano minimal residual alveolar ridge dimensions mandible
12 mm above IAC for 10 mm Implant
Therefore height = implant (10 mm) + safe zone (2mm)
Pano minimal residual alveolar ridge dimensions max
11mm from maxillary sinus for 10 mm implant
Height = min. Implant height (10mm) + safe zone (1mm) = 11mm
CBCT advantages
Assess available alveolar bone in 3D - quality, height and width
Bone and proposed implant inclination
Spatial relationship of Anatomic structures
CBCT disadvantages
Limited availability, moderate cost, technique sensitive, extended learning curve
Application of CBCT in implantology
Significant increase in radiation dose to the patient (c.f pano and selected PA) is offset by increased reliability and accuracy in assessment and predictability in treatment outcome
CBCT avoiding para sagittal parallax error
Displacement or difference in the apparent position of an object viewed along two different lines of sight
CBCT avoiding vertical parallax error
Displacement or difference in the apparent position of an object viewed along two differnet lines of sight
CBCT software measurement/virtual implant simulation
Review orthogonal images
Review 3D volumetric rendering
Create reformatted panoramic image and cross sections
Measure bone volume at specific sites
Select appropriate virtual implant type and size
Prosthetcially driven virtual implant placements- Oro-facial, apical-coronally, mesiodistally
