Week 8- Cementing and Bonding Flashcards
What are advantages of digital dentistry?
- Better fitting restos
- More diversity
- Increased speed in resto techniques
- More time efficient solutions at lower cost
- More predictable outcomes
Should you bond or cement crowns if there is adequate retention from prep?
Cement (rely x unicem)
What is the potential issue with 3Shape TRIOS MOVE +?
May not take into consideration occlusal factors (lengthening teeth might be issue in protrusion)
What is the curing method of rely x unicem and how long does it take to set?
Dual cured. If not light cured, takes 4 minutes to set.
What would be required for this tooth before placing crown?
Crown lengthening (electrosurgery or laser to remove gingival tissue to get more length of crown)
Why does zirconia need to be cleaned after try in?
Phosphate and calcium ions from saliva contaminate zirconia fitting surface
What is used to clean zirconia?
Ivoclean (removed calcium and phosphate). Paint on and wash off
Why does lithium disilicate glass not need to be cleaned after saliva contamination?
It does not attract calcium and phosphate ions
What should be placed on lab form for zirconia crown?
Aluminium oxide blast fitting surface (micromechanical retention)
How is ivoclean used?
- Wash contaminated fitting surface with water and dry
- Cover entire bonding surface of resto with layer of ivoclean using an applicator
- Allow 20 secs for ivoclean to absorb phosphate contaminants.
- Rinse with water and dry
Why doesn’t phosphoric acid gel clean zirconia fitting surface?
Etching gel inhibits bonding agent to form a bond with the surface
How is EMAX etched?
HF acid
What is used instead of HF acid for etching emax at JCU dental (due to safety concerns)?
Ivoclean and monobond
How is ivoclean and monobond used?
- Paint on fitting surface for about a minute
- Wash off and dry
- This silanates emax surface and resin can be bonded.
How is SpeedCEM plus used?
- Following AlO blast and ivoclean, speed cem is applied onto fitting surface.
- Crown is placed in pts mouth
- Light cure margins for 5 seconds and remove excess cement
What is the bonding mechanism of SpeedCEM?
Adhesive monomer in material is MDP (phosphate and methacrylate)
What can be used to cement zirconia crown?
Rely x unicem
SpeedCEM
Why should you polish zirconia after adjusting it?
Microcracks develop which must be polished away.
How should zirconia crowns be adjusted and polished?
- Check occlusion with articulating paper
- Take out of mouth and place on die
- Use slow speed to adjust
- Polish with Zircon-Brite
- Clean and cement in place
How should emax be adjusted?
- Bond in place before checking occlusion.
- Emax will crack if adjusted when not bonded.
Why does excess cement need to be removed after crown placement?
Avoid plaque formation which can lead to tooth sensitivity and perio disease.
How can gingival margins of crowns be finished?
Non-cutting safe end finishing burs that will protect soft tissues.
Can GIC be used for cementing veneers and crowns?
No
