CADCAM Flashcards
What is an impression in GPT?
A negative likeness of copy in reverse of the surface of an object
An imprint of the teeth and adjacent structures for use in dentistry
Why are models a useful idea?
They form good records (pre-treatment or study models)
They facilitate diagnostic waxup
Post-treatment
Medico-legal
Restorations/prosthesis fabrications can be made using them
What is the aim of impression making?
Producing a replica of the tooth
100% accurate recording of the margin
Produce replica of surrounding teeth enough to articulate cast
Proximal contacts
Occlusal surfaces
Contralateral
Anterior teeth to establish anterior guidance and disclusion
How far above the margin should the impression be taken?
0.5mm or more beyond the margin (ease of die trimming or emergence profile)
What are the steps of taking a polymeric/conventional impression?
Tray and tray adhesive
Gingival retraction
Moisture control
Block undercuts (causes distortion of impression)
Assemble automix (and bleed cartridges)
Communication with the DA (not able to be done alone)
Execute the impression
Setting time
Impression removal
Assess result
What are the steps needed for digital/scan impressions?
Set up trios cart fasten tips
Scan calibration
Enter patient and tooth prep details
Gingival retraction
Moisture control
Execute scan
Assess result
What is the hybrid workflow?
Prep
Conventional impression
Lab (pour model, film model, film die, scan model or use digital impression, CAD, CAM, finish)
Insert/restoration deliver
What are the digital impression benefits?
Quality and workflow improvements
Innovativeness and patient acceptance
Time benefits
Financial advantages
Communication
Leadership and early adopter benefits (very few dentists have access to these in Australia)
What are the disadvantages to using digital impressions?
Skills update and transition stress
Digital confidence and mindset
Costs and investments
Accuracy concerns
Medico-legal concerns
Time
What is needed for a digital impression?
Camera needs light (not too little not too much) Overhead or loupe lights can interfere, Metals can reflect
Risk of fogging so there’s a built in heater
Decontamination - scanning tips
Damage to lens/mirror
Gyro / photos / stitching needs calibration and time and position can distort the image.
How should scanning technique look? (Overall style of scanning)
Systematic
Steady, allow time for stitching/acquisition
Beginners (Watch the tip and listen for the clicks until you are spatially aware of teh scanner (avoid tongue, soft tissue, and the uvula)
What is the technique used for scanning with CADCAM?
Press button
Start with occlusal over 5s or 6s as it does best with flat surface/level movements parallel to the occlusal plane
Then direct the scanner mesially
Rotate buccal/lingual then finish
Press button
Assess result
What are the steps undertaken at ohcwa/uwa dental school?
Finalize tooth preparation
Digital impression/scan
Temporary crown made and ready to cement
Polymeric/conventional impression
What should be done if the prep needs modification?
If your prep requires modification or checking with scanner then defer impression
If you modify the prep you need to redo the scan
What are the important considerations with soft tissue?
Capturing soft tissue
Soft tissue interference (subgingival margins(
Muco0static bs muco-compresssive forces.
