Mock Oral Board Flashcards
How would you manage this patient’s estehtic concers?
What is the etiology?
- Etiology
- Fluorosis
- Pre-eruptive trauma
- Demineralization
- Treatment options would range from most conservative to more aggressive
- Microabrasion
What is microabrasion?
- Chemo/mechanical removal of superficial enamel
- Uses acid/abrasive solution with mechanical/rotary instruments
What is the active ingredient in enamel microabrasion?
- HCl acid (Prema 10% HCl)
How deep can the fluorosis be for enamel microabrasion to work?
- For lesions less than 200 microns
- Most brown spots respond well
- 25-50% of white spot lesions are too deep
- No long term clinical studies
What are some indications for chariside bleaching?
- Mild fluorosis
- Mild tetracycline staining
- Stains from aging
- Diet
- Smoking
What are contraindications for bleaching?
- Dark staining
- Multiple large restorations
- moderate to severe tooth sensitivity
- Pregnant or nursing patient
What are active ingredients for bleaching?
- In office: higher concentrations of hydrogen peroxide 25-35%
- Home: 3-15%
- Or 10-35% carbamide peroxide
What is the concentration of hydrogen peroxide in white strips?
6-14%
Is there any difference in efficacy between home bleaching and combined bleaching (office and home)?
No difference after 1 week
How do white strips compare to home bleaching in trays?
- Clinical study by Costa - no difference
How do light or laser assisted bleaching compare to unassisted chairside bleaching?
- Controlled clinical studies show no significant improvement
What does the research say about Icon?
- A recent clinical sutyd found a significant improvmement in white spot lesions after orthodontic treatment that was stable for 6 months
- However several laboratory studies hve suggested that resin infiltrated white spot lesions may be more susceptible to incresed staining
You have a patient that presents with multiople class V carious lesions - how do you manage the isolation of these teeth?
- Surgical isolation (single envelope flap)
- Modify 212 clamp (bend lingual beak occlusally)
- Punch RD hole to facial, holes far apart
What are the various crystalline phases of zirconia?
- Monoclinic
- Tetragonal
- Cubic
What factor determines the phases of zirconia…
- Stability of these phases is dependent on increasing temperature
- Possible to achieve each phase at room temperature by adding stabilizing oxides
What is the strongest form of zirconia?
- Tetrongonal phase which is a high temperature phase stablized by adding 3 mol% yttria and therefore known as 3% yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP)
What have newer zirconia formulas looked like regarding yttria content?
- Newer more translucent materials have been crated using 4 mol% and 5 mol% yttria partially-stabilized zirconia (4Y-PSZ and 5Y-PSZ)
What is transformation toughening?
- In a ceramic composed of tetragonal zirconia dispersed in a zirconia matrix, the stress field advancing ahead of a propagating crack transforms the small tetrongal particles to larger monoclinic particles
- The newer zirconia products that utilize the cubic phase at a higher ratio do not exhibit the transformation toughening exhibited by 3Y-TZP materials and have reduced strength.
If we need to bond to zirconia, would we etch with HF acid?
- Polycrystalline ceramics are not etchable with acids and can be more challenging to bond.
What techniques are available to bone to zirconia?
- Ceramic primers contain bi-functional monomers such as 10-MDP which can bond to metal oxides in crystalline ceramics and methacrylate in resin cements.
- Or adhesive resin cements that contain MDP could be utilized
What is tribochemical silica coating?
- The use of silica-coated particle to embed silica into a substrate such as poloycrystalline ceramics or composite to create a surface that may be silanated to increase bond strength
- Example: CoJet
Can we air-abrade zirconia materials to roughen the intaglio and gain more rentention?
- Concern is with unwanted phase transformation…
- But recent systematic reviews demonstrate that tetragonal zirconia may be safely air-abraded
- Little research exiss on the effect of air-abrasion on the new weaker cubic zirconia materials
What can you tell me about the millable ceramic polymer materials?
- Essentially these are composite resin restorative materials that have been highly polymerized
- Potentially greater fracture toughness
- Better edge quality
- No crystallization necessary
- New study suggests a potentially higher rate of debonding for full crowns for some of these materials
- Bonding to pre-polymerized composite may be problematic and they have a lower modulus of elasticity, so they tend to flex under function
What do clinical studies suggest as far their use as crowns?
- Lava Ultimate is essentially Filtek Supreme Ultra, a nanocomposite that is highly polymerized
- Vita Enamic is a resin-infiltrated ceramic network that may peform more similar to glassy ceramics.
- Limited clinical studies are available to recommend this class of millable material
- May be more suitable for inlays/onlays
What can you tell me about recent agreements and legislation to reduce the palcement of amalgam restorations?
- The European Union recently enacted a law that prohibits the use of amalgam starting in July 2018 in deciduous teeth
- Children < 15 years
- and pregnant breastfeeding women
What is the Minamata Convention?
- A meeting that took place in November 2013
- Sponsored by the United Nations
- Over 120 countries signed a global agreement to reduce and use, emissions, and handling of mercury across a variety of industries to include electronics, energy, mining, and waste.
- For denistry, it call for the phase down of the use of amalgam