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
What can you tell me about amalgam seperators?
- They reduce the amount of amalgam discharted into the sewer system from dental vacuum systems
How do amalgam seperators work?
- By sedimentation
- Filtration
- and ion exchange
Is there a national EPA ruling on the use of amalgam seperators?
- EPA released a ruling in July 2017 requiring dental practies nationwide to install amalgam seperators
- The rule closely follows ADA’s own best managemnt practices and incorporates three of BMPs
- Requiring use of seperators
- Prohibiitng providers from flushing down a drain waste amalgam (such as from traps or filters);
- Prohibiting the use of bleach or chlorine-containing clearners thay may lead to the dissolution of solid mercury when cleaning chair-side traps and vacuuum lines.
- The date for compliance for most dentists will be at the end of 2020
What do new ADA guidelines on nonrestorative treatment for carious lesions regarding coronal surface of permanent teeth?
- Prioritize the use of 38% SDF solution (biannual application) over 5% sodium fluoride varnish (application once per week for 3 weeks)
What do new ADA guidelines on nonrestorative treatment to arrest or reverse noncavitated carious lesions on occlusal surfaces of permanent teeth?
- Sealants + 5% F varnish (application every 3-6 months) or…
- Sealants alone over 5% sodium fluoride varnish alone or
- 1.23% acidulated phosphate fluoride gel (application every 3-6 months or
- 0.2% sodium fluoride mouthrinse (once per week).
What do new ADA guidelines on nonrestorative treatment to arrest or reverrse noncavitated carious lesions on facial or lingual surfaces of permanent teeth?
- Use 1.23% acidulated phosphate fluoride gel (application every 3-6 months) or
- 5% sodium fluoride varnish (application every 3-6 months)
What do new ADA guidelines on nonrestorative treatment to arrest or reverse noncavitated carious lesions on approximal surfaces of permanent teeth?
- Use 5% infiltration + 5% sodium fluoride varnish (application every 3-6 months
- Resin infiltration alone
- Resin infiltration + 5% sodium fluoride varnish (application every 3-6 months or
- Sealants alone
What do new ADA guidelines on nonrestorative treatment to arrest or reverse noncavitated and cavitated carious lesions on root surfaces of permanent teeth?
- Prioritize use of 5,000 ppm fluoride (1.1% sodium fluoride) toothepaste or gel (at least once per day) over 5% sodium fluoride varnish (application every 3-6 months)
- 38% SDF + potassium iodide solution (annual application)
- 38% SDF solution (annual application) or
- 1% chlorhexidine + thymol varnish (application every 3-6 months).
What is silver diamine fluoride?
- SDF is produced as a colorless liquid containing silver particles and 38% (44,800 ppm) fluoride ion
What is the chemical breakdown of SDF?
- 25% silver
- 8% ammonia
- 5% fluoride
- 62% water at pH 10.5
How does SDF work?
- The silver works as an antimicrobial
- The fluoride supports remineralization
- The ammonia in the formula stabilizes high concentrations in solution
What is the SMART technique?
- Silver modified atraumatic restorative technique
- This involves placing an opaque glass ionomer cement atop an SDF traeted carious lesion to mask any staining
What is CAMBRA?
- Caries Management By Risk Assessment
- Identify the cause of disease by assessing risk factors and correct problem by addressing each risk factor
What are some risk factors in caries risk assessment?
- Diet
- CHO consumption
- # of active lesions over past few years
- # of DMF teeth
- Salivary function
- Oral hygiene status
- F exposure
- Root surface exposure
- Orthodontics
What is the critical pH of enamel?
5.5
What are two major types of resin-based bonding agents sytems available?
- Etch and rinse
- Self etch
What is selective etching?
- Selective etching is the placement of phosphoric acid on enamel only when using self-etching bonding agents.
What does research say about selective etching?
- Recent systematic reviews of the literature clinical studies found no difference in rentetion, however fewer marignal defects and improved marginal integrity and less marginal discoloration were observed with selctive etch.
What did a recent systematic review find about the use of adhesive bonding agents with sealants?
- Adhesive systems increase the retention of pit and fissure sealants and etch-and-rinse systems are preferable to self-etching systems
What bonding agent do you use and why?
- Systematic reviews (Peumans 2014) of controlled clinical studies clearly demonstrate that.
- Non simplified bonding agents
- 2-Step self-etch bonding agent like Clearil SE Bond is the best performing bonding agent with the lowest failure rate folowed closely by the three-step etch and rinse bonding agent, OPtibond FL in NCCLs
What can you tell me about the new Universal Adhesives?
- “Simplified” bonding agents that may be placed in etch-and rinse-, self-etch or selective etch modes
- Most are lower in pH and contain an MDP-type functional monomer, which is better for bonding to dentin
- May contain glass and oxide ceramic primers
- But…may not be as universal as claimed…
- Recent laboratory studies suggest that the bond strengths of Scotchbond Universal, (contains silane) to glassy ceramic, is not as effective as silane alone
- “Simplified may be more susceptible to hydroysis over time
- Very limited clinical research is available evaluating this new class of bonding agents
What is immediate dentin sealing (IDS)?
- Management of the dental tissues between the preparation and provisionalization phase of restorative treatment may play a role in the success of indirect bonded restorations
- In the development of these restorations, the exposed vital dentin immediately after tooth preparation is susceptible to insult from bacterial infiltration and microleakage during the provisionalization phase.
- Bacterial and fluid penetration through the exposed dentinal tubules can potentially result in colonization of microorganisms, post-operative sensitivity, and the potential for subsequent irritaiton of the pulp.
- In attempt to avoid these possible sequelae, immediate application of a bonding agent after preparation has preposed with the IDS technique
What are the results of published studies regarding Immediate Dentin Sealing (IDS)
- IDS has been studied in the laboratory and significantly improved over the years with positive results with respect to bond strength, gap formations, bacterial leakage, and post-cementation hypersensitivity.
- Although laboratory studies have been favorable, very limited clinical research has been published evaluating the efficacy of this technique
- The techniques involves additional steps
- A recent 3 year clinical study found no difference between immediate and delayed dentin sealing of IPS e.max Press restorations.
What are Matrix Metalloproteinases?
- MMPs are a class of zinc and calcium dependent endopeptidases that are trapped within the mineralized dentin matrix during tooth developemnt
- The release and the subsequent activation of these endogenous enzymes during dentin bonding procedures are thought to be responsible for the in vitro manifestation of thinning and disappearance of collagen fibrils from incompletely infiltrated hybrid layers has also been confirmed in in vivo studies
How do you counteract MMP when using bonding agents?
- The application of chlorhexidine, a well known antibacterial agent with MMP inhibiting properties when applied to acid-etched human primary dentin resulted in the preservation of collagen integrity within the hybrid layers
What do recent studies regarding MMPs report?
- Recent systemiatic review of ten clinical studies of Class I and V restorations found no difference with 6 to 36 month follow-up with or without the use of MMP inhibitors
What composite do you use and why?
How would you classify it?
- Filtek Supreme Ultra which is a Nanocomposite
- Z250 which is a Microhybrid
What is a Giomer?
- A composite similar to traditional methacrylate-based composites, but contains pre-reacted glass-ionomer particles that may provide a source of fluoride release
- Very limited clinical stuides avilable
- One recent long-term study was published in JADA, but it was not compared to any other products
What is an Ormocer?
- Organically modifed ceramic
- Fillers and resin matrix based on silicon dioxide
- Recent clinical studies finding no difference between Ormocers and traidiotnal methacrylates in Class I and 2 restorations over 5 years
What are bioactive resin materials?
Can you name some examples?
- Calcium silicate and calcium aluminate materials that form apatite-like material on its surface
- Activa (Pulpdent)
- Limited research available on these newer bioactive resin materials
Why do we place estehtic restorative composites in increments of no more than 2 mm?
- Esthetic restorative composites are placed in 2 mm increments because of the attenuation of the light and concerns of polymerization-shrinkage stress
What can you tell me about the new bulk-fill composite resins?
- The new bulk-fill restorative composites can be cured up to 5 mm and the flowable composites reportedly up to 4 mm
How do bulk-fill composites gain greater depth of cure?
- Greater depth of cure is gained by the use of more photoinitiators
- Additional photoinitiator types
- Greater translucency
What is tri-sited curing?
- Tri-sited curing is the curing of the composites from the occlusal, buccal and lingual to gain greater polymerization and additional depth of cure
How are the manufacturers reducing shrinkage stress in bulk-fill materials?
- Shrinkage stress may be reduced in some bulk-fill materials by incorporation of stress-reducing resins
What do the clinical studies demonstrate so far comparing the performance of incremental vs. bulk-fill technique?
- For the most part, laboratory studies confirm the manufactueres’ claims.
- A recent systematic review of limited clinical studies and a consensus by SMEs concluded that the performance of bulk-fill composites should be similar to that of incrementally placed composites, but with easier placement.
- However, multiple, long-term clinical studies are not yet available
What did recent systematic reviews of controlled clinical studies find as far as longevity of posterior amalgam restorations compared to composite restorations?
- A recent Cochrane systematic review (2014) found that posterior composite restorations were 2 times as likely to fail and had twice the risk of secondary caries compared to posterior amalgam restorations.
- Another recent systematic review (2015) found that posterior composites had a higher risk of secondary caries than amalgam restorations, but with no difference in fracture. (Fracture toughness should be the same in both)
What is the difference between Partial Caries Removal (PCR) and Stepwise Total Caries Removal (SWT)?
- Partial caries removal - the dentist removes part of the dentinal caries and seals what is left into the toth permanently
- Stepwise excavation - this technique removes caries in stages over two visits some months apart, allowing the dental pulp time to repair itself and lay down dentine
What were the results of recent systematic review regarding Partial Caries Removal and Stepwise Total Caries Removal?
- Successful vitality and restorative outcomes for both PCR and SWT at 2 years.
- PCR had fewer pulpal complications over a 3 year perio than SWT
What is the evidence-base for non-fluoride containing preventative agents like Xylitol?
- A recent Cochran systematic review (2015) found low quality evidence that fluoride toothpaste containing xylitol may be more effective than fluoride only toothpaste in preventing caries
- Low quality and insufficient evidence exists to determine whether any other xylitol-containing products can reduce caries
What does the research say about Amorphous Calcium Phosphate (ACP)?
- Systematic reviews suggest that ACP may be equal to fluoride in its reminderalization effect, but the research is more equivocal whether ACP may augment fluoride in reducing demineralization and enhancing remineralization
- A recent systematic review found a lack of evience for the use of MI Paste/Plus over fluoride for prevention of early dental caries
- There is low quality evidence to support the use of MI Paste/Plus for the treatment of white spot lesions from orthodontics
- No benefit from MI Paste/Plus (with fluoride) over MI Paste
