Quiz 2 - Spring

Question 1

What is the occlusal reduction for a all ceramic partial coverage restoration?

Answer 1

2.0 mm clearance both function and non-functional

Question 2

What is the name of the stubby 018 diamond and what are its measurements?

Answer 2

It is the 6845KR-018 diamond and it is 1.3 mm at the tip and 1.9 mm near the shank

Question 3

What is the name of the skinny tip-only diamond used for rounding?

Answer 3

889-009 diamond

Question 4

What are the main five indications for all-ceramic partial coverage?

Answer 4

1. Both vital and non-vital teeth
2. Excellent esthetic requirements, but not superior
3. Significant mesial and or distal damage with buccal or lingual tooth structure remaining
4. Must have enamel to bond with on both buccal and lingual
5. Ideal when axial reduction for full coverage crown would otherwise remove most of remaining buccal and or lingual tooth structure

Question 5

What are the requirements to be able to do a all ceramic partial coverage?

Answer 5

Must have enamel to bond with on both buccal & lingual (The more the better…)
Must be able to maintain an isolated, dry field of operation
What is the patient’s gingival health status? What is the patient’s plaque control ability? Is an antisialogogue indicated?
Rubber dam isolation for bonding is required at SOD
Must isolate in such a way that proximal surfaces of adjacent teeth are exposed Isolation must allow unobstructed seating of restoration
Isolation must not interfere with removal of excess bonding resin
NOTE: If significant sub-gingival component to the restoration exists that could compromise bonding, then a restoration that does not depend upon bonding is indicated.

Question 6

What do you do if intaglio surface of restoration is contaminated?

Answer 6

If the restoration is tried in intraorally and the intaglio surface is contaminated with saliva, blood, try-in paste, etc., it must be cleaned before final bonding. Use 37% PhO4 for 60 seconds, followed by rinsing and placing in water and ultrasonic for five minutes. (Dr. Taylor says to apply 37% Phosphoric Acid to intaglio surface for 30 seconds, then do 30 second spray rinse of restoration with air/water syring, air dry, apply silane to intaglio surface, then air dry.
If an alternate method is desired, Ivoclar recently introduced Ivoclean, which has been specifically developed to clean ceramic after intraoral try-in procedures. The intaglio surface is coated with Ivoclean for 20 seconds, rinsed thoroughly with water, and dried with oil-free air
Ivoclean creates optimum conditions for adhesive cementation for maximum bond strength. While phosphoric acid may be used to clean the surface of glass ceramic restorations, its surface-deactivating effect on zirconium- oxide ceramics and base metal alloys inhibits bonding. In a study, restorations cleaned with Ivoclean after intraoral try-in demonstrated the highest bond strengths when compared to other cleaning methods, regardless of material type.

Question 7

Why use phosphoric acid instead of hydrofluoric acid to clean intaglio surface of restoration?

Answer 7

Hydrofluoric acid is a poisonous and caustic liquid that is extremely irritating to the skin and lungs, and concerns about its use intraorally have been reported. Thus, in intraoral repair, phosphoric acid is preferred for etching and decontamination of bonding surfaces. Additionally, phosphoric acid has previously been proposed as a ceramic surface cleaning agent based on the assumption that it is a good organic solvent.

Question 8

What are the bonding appointment steps for an all ceramic partial coverage?

Answer 8

This is a 4-handed procedure
¡ Anesthetize if tooth is vital
¡ Isolate with cotton rolls &/or absorbent cards
¡ Remove temporary
¡ Clean excess temporary material &/or bonding agent from tooth with hand scaler
¡ Gently scrub prepared tooth with flour of pumice in polishing cup
¡ Thoroughlyrinsepreparedtooth&adjacentteeth
¡ Replacecottonroll&/orabsorbentcard
¡ Drypreparedtoothandadjacentteeth
¡ MarkocclusalcontactsonadjacentteethinMI
¡ Place restoration on prepared tooth
¡ Check proximal contacts (Assistant holds while you check with floss.)
¡ Check margins
¡ Check occlusion with contrasting color of articulating ribbon or paper – Light touch only, NO heavy closing or grinding at this point! Evaluate only MI, as un-bonded restoration will tip and move on prepared tooth in excursive movements.
¡ Adjust as necessary
¡ Decide shade of esthetic resin cement (either Variolink or Calibra) you would like to use and set aside (DO NOT dispense yet!) – Use in dual cure mode (mix base + catalyst)
¡ Apply 37% phosphoric acid etch gel to intaglio surface of restoration for 30 seconds to remove salivary &/or blood contaminants
¡ 30 second spray rinse of restoration with 3-way air/water syringe (Exercise care not to allow restoration to slip from wet, gloved fingers and become an airborne projectile.)
¡ Thoroughly air dry restoration
¡ Apply silane to intaglio surface of restoration
¡ Air dry
¡ Isolate tooth with rubber dam. (Exercise caution not to create gingival bleeding!)
¡ 37% phosphoric acid etch of prepared tooth enamel for 15 seconds.
¡ Place Microprime over entire prepared tooth surface – wait 60 seconds.
¡ Air-dry with 3-way syringe until liquid has evaporated. (Shiny surface will likely remain.)
¡ Place 2nd coat of Microprime – wait 30 seconds.
¡ Air dry until liquid has evaporated. (Shiny surface will likely remain.)
¡ Mix Photobond and apply to both intaglio surface of restoration and prepared surface of tooth.
¡ Thin Photobond on both surfaces with gentle stream of air from 3-way syringe. (Clear line of H2O before moving to Photobond!)
¡ Mix and apply esthetic bonding resin cement to intaglio surface of restoration.
¡ Place restoration onto prepared tooth
¡ Extinguish overhead light and rotate amber headlamp filter into active position
¡ Assistant now holds restoration securely onto tooth via steady, firm pressure, directed apically (A pair of closed cotton forceps works nicely for this.)
¡ Wipe excess resin cement from buccal & lingual margins with scaler (DO NOT use cotton roll for this as marginal deficiencies may be created.)
¡ Floss (your 2nd piece) proximal surfaces, exercising caution not to cause gingival bleeding
¡ “Tack-cure” occlusal surface while still maintaining firm apical pressure on restoration
¡ Breathe…
¡ Assistant my now discontinue application of apical pressure on restoration
¡ Remove as much excess resin cement as you are able to, exercising caution not to disturb restoration
¡ Final light-cure of bonded restoration:
Straight occlusal (20 seconds) Distal-lingual (20 seconds) Mesial-lingual (20 seconds) Distal-buccal (20 seconds) Mesial-buccal (20 seconds)
¡ Remove remainder of excess resin cement and finish margins as needed (Usually, hand instrumentation alone is sufficient for this, unless either marginal gap is significant or large pieces of excess resin remain attached to tooth.)
¡ Remove rubber dam
¡ Check occlusion, including excursive movements and adjust, intraorally, as necessary
¡ Verify fit and feel of new restoration with patient
¡ Give post-operative instructions:
No chewing precautions now
If anesthetized, “ Your numbness may last another hour or two. Be careful not to bite your tongue, cheek or lip.”
Advise patient that some post-operative sensitivity, for several days following, is normal.
¡ Dismiss patient

Question 9

What are the steps of bonding the temporary for an all ceramic partial coverage made of Triad Provisional material?

Answer 9

■ Rinse and dry prepared tooth
■ DO NOT etch unless there is little to no mechanical retention &/or resistance
■ If etching is necessary, only spot etch a small area of buccal and lingual enamel
■ Apply bonding agent to intaglio surface of temporary and prepared tooth
■ Apply a layer of flowable composite to the intaglio surface of the temporary
■ Place temporary on prepared tooth
■ While assistant is holding temporary in place, remove excess flowable composite
■ Make sure to floss proximal surfaces
■ Cure temporary into place
■ Remove any remaining excess flowable composite with scaler

Question 10

What are the three silica-based ceramic materials?

Answer 10

1. Feldspathic porcelains
2. Leucite-reinforced ceramics
3. Lithium disilicate ceramics

Question 11

What are the two non-silica-based ceramic materials?

Answer 11

1. Zirconia

2. Alumina

Question 12

What are the flexural strengths of the different types of ceramics?

Answer 12

Feldspathic porcelain 65-120 MPa
Leucite-reinforced ceramic 120-140 MPa
Lithium disilicate ceramic 300-400 MPa
Alumina 650 MPa
Zirconia 800-1500 MPa

Question 13

What are the indications for Feldspathic porcelains?

Answer 13

Indications for feldspathic porcelains

• Highly esthetic veneers or anterior crowns in cases where color masking is not an issue

Question 14

What are the indications for leucite-reinforced ceramics?

Answer 14

Indications for leucite-reinforced ceramics
• Esthetic veneers and anterior crowns
• As a layering porcelain on leucite-reinforced, lithium disilicate, alumina, or zirconia cores

Question 15

What are the indications for lithium disilicate ceramics?

Answer 15

Indications for lithium disilicate ceramics
• Veneers
• Premolars and molars - inlays, onlays and crowns
• Three-unit bridges – anterior and premolar region

Question 16

What are the indications for zirconia-based ceramics?

Answer 16

Indications for zirconia-based ceramics
• Anterior and posterior crowns
• Bruxers – full-contour crowns
• Anterior and posterior bridges (maximum 14-unit bridges, span
depends on product and number of abutments)
• Endodontically treated teeth
• Implant abutments
• Inlay bridges
• Maryland bridges
• Block-out of darkened tooth structure or cores

Question 17

What is the composition of feldspathic porcelains?

Answer 17

Leucite (potassium aluminosilicate) and glass

Question 18

What is the composition of leucite-reinforced ceramics?

Answer 18

45% leucite

Question 19

What is the composition of lithium disilicate ceramics?

Answer 19

65% lithium disilicate crystals dispersed in glassy matrix

Question 20

What is the most common type of zirconia-based ceramic in dentistry?

Answer 20

Partially stabilized zirconia, specifically, yttria-stabilized zirconia (Y-TZP)

Question 21

Which type of ceramic is a worry for wearing down the opposing dentition?

Answer 21

Zirconia

Question 22

What is the definition of an adhesive resin cement?

Answer 22

Cement based on acrylic or diacrylate resin with adhesive monomers that bond well to metal substrates. Adhesive resin cements may require a separate primer for bonding to ceramic and tooth substrates.

Question 23

What is the definition of an esthetic resin cement?

Answer 23

Tooth-colored or translucent cement based on diacrylate resin that requires a bonding agent for adhesion to tooth structure and separate primers for bonding to ceramic substrates.

Question 24

What is the definition of a self-adhesive resin cement?

Answer 24

Cement with adhesive components that eliminate the need for separate primers for bonding to tooth structure and ceramic substrates.

Question 25

What is the definition of a silane primer?

Answer 25

(Silane coupling agent) – primer based on silane used with silica-based ceramics (feldspathic porcelain, leucite-reinforced ceramic, lithium disilicate ceramic).

Question 26

What is the definition of a ceramic primer?

Answer 26

Primer based on acidic adhesive monomers used with alumina- and zirconia-based ceramics. Ceramic primers may contain silane and metal primers.

Question 27

What are the characteristics of esthetic resin cements?

Answer 27

• Self-etch or total-etch bonding agent is needed for bonding to tooth substrates.
• Silane or ceramic primer is needed for all-ceramic restorations.
• Curing mode options – can be light- or dual-cured.
• Light-cured cement is available for veneers.
• Stronger mechanical properties than self-adhesive resin cement.
• Multiple shades available.
• Most esthetic resin cements provide water soluble try-in pastes.

Question 28

What are the characteristics of adhesive resin cements?

Answer 28

• Primer is needed for bonding to tooth substrates.
• Silane coupling agent is needed for silica-based ceramics.
• Can bond directly to zirconia without primer.
• Curing mode options – can be light-, dual-, or self-cured.
• Several shades available.
• May release fluoride.

Question 29

What are the characteristics of self-adhesive resin cements?

Answer 29

• Self-etching – no phosphoric acid or special primer needed for bonding to tooth substrates.
• Can bond directly to zirconia without primer.
• Curing mode options – can be light-, dual-, or self-cured.
• May release fluoride.
• Usually available in universal, translucent and opaque shades.

Question 30

What is the composition of resin cements?

Answer 30

Resin cements are composed of diacrylate resins and glass filler. They are usually dual-cured resins that can be light activated and can self-cure.

Question 31

What is the pH change that self-adhesive resin cements undergo during setting?

Answer 31

During setting, self-adhesive resin cements typically undergo a change in pH from acidic (pH 2-3) to less acidic (pH 5-6). The early acidity of the cement allows it to etch and adhere to tooth structure.

Question 32

Which cements require etching and bonding, and what are the details?

Answer 32

Esthetic resin cements and adhesive resin cements require etching and priming steps. A silanating agent is required with esthetic resin cements for bonding to silica-based ceramics. A zirconia primer is required with esthetic resin cements for zirconia bonding. Follow the manufacturers’ instructions on how to apply such bonding systems to get strong bonding and enough working time. The working time of the cements may be accelerated with the primer and the bonding agents. Most of these dual-cured cements are paste-paste system with auto-mix dispensers. Excess cement can be removed easily after brief tack-curing (2-5 seconds) with a curing light.

Question 33

The separate use of a bonding agent is recommended with self-adhesive resin cements. True or False?

Answer 33

False. Although bonding agents may be compatible with self-adhesive resin cements, their use makes the manipulation more complicated and does not dramatically improve bond strength to tooth structure. Higher bond strengths to tooth structure can be obtained with esthetic resin cements that are bonded with separate bonding agents.

Question 34

What can primers do and with which type of ceramic are silanating agents used?

Answer 34

Primers improve bonding between resin cements and various restorative materials and can be classified based on the substrate (silica-based ceramics, alumina, zirconia, alloy) for which they are intended. Silanating agents are used with silica-based ceramics (feldspathic porcelain, leucite-reinforced ceramic, lithium disilicate ceramic). Modern silanating agents are one-bottle systems with good shelf life.

Question 35

What key ingredient is involved with primers used for alumina or zirconia ceramics?

Answer 35

Acidic adhesive monomers

Question 36

In general, restorations prepared from feldspathic porcelain and leucite-reinforced ceramic should be bonded with adhesive or esthetic resin cements. True or False?

Answer 36

True. They are recommended because of their higher mechanical properties and higher bond strength to tooth structure than others.

Question 37

What are silica-based ceramics pre-treated with before silanation and placement of resin cement?

Answer 37

Typically, silica-based ceramics are pre-treated with hydrofluoric acid gel (HF) before silanation. HF can dissolve the surface of silica-based ceramics and roughen it.

Question 38

Hydrofluoric acid gel is used to roughen up the surface of zirconia before placement of resin cement. True or False

Answer 38

False. If ceramic primer, self-adhesive cement or adhesive cement that contains an acidic adhesive monomer is used, air-particle abrasion is the easiest way to form a roughened surface to increase mechanical retention. Zirconia is a non-silica-based ceramic and thus doesn’t etch using traditional methods. Retention of zirconia-based ceramic restorations depends on mechanical roughening of the surface and chemical bonding with adhesive monomer in special primers or resin cements. An acidic adhesive monomer such as MDP bonds to zirconia-based ceramics. The phosphate ester group of the acidic monomer results in chemical bonding to metal oxides (MxOy, oxidized surface of base-metal alloys), zirconia-based ceramics and other ceramics. It is effective, therefore, to use self- adhesive or adhesive resin cement including an adhesive monomer for cementation. In the case of esthetic resin cement, the ceramic primer including an acidic adhesive monomer is needed as a pre-treatment.

Question 39

What was the difference of using air abrasion vs a fine diamond to roughen up the ceramic surface of a zirconia-based crown?

Answer 39

Sandblasting with alumina results in a roughened ceramic surface, whereas abrasion with a fine diamond produces a smoother smear layer on the ceramic surface. Both types of mechanical treatment resulted in higher bond strengths than bonding to the sintered surface of the zirconia-based ceramic.

Question 40

Self-adhesive resin cements and adhesive resin cements show a lower incidence of sensitivity than traditional crown and bridge cements. True or False?

Answer 40

True

Question 41

Marginal staining of self-adhesive resin cements and adhesive resin cements was reported to be higher than that of traditional non-adhesive, crown and bridge cements. True or False?

Answer 41

False, was reported to be lower

Question 42

Esthetic resin cements were shown to be the most commonly selected for cementation of zirconia-based ceramic restorations. True or False?

Answer 42

False. Self-adhesive resin cements are.

Question 43

What type of cement is the best choice for zirconia-based ceramic restorations when the restoration does not require the highest retention?

Answer 43

Self-adhesive resin cements are the best choice for zirconia-based ceramic restorations, when the restoration does not require the highest retention. They are less technique sensitive than bonding with adhesive or esthetic resin cements and offer more retention and better marginal sealing of tooth structure than the traditional glass ionomer cements. No separate bonding agent is necessary, reducing much time and effort. Cleanup is also easy with self-adhesive resin cements. The cement can usually be peeled off the marginal areas, with the advantage of leaving less cement in the area after cementation. Post-operative sensitivity of self-adhesive resin cements has been reported to be less than traditional crown and bridge cements.

Question 44

What are the simple rules for selecting which cement to use for feldspathic porcelain restorations?

Answer 44

• Feldspathic porcelains require resin cement bonded to both tooth structure and ceramic.
• Use a dual-cured esthetic resin cement with a dual-cured total-etch (etch-and-rinse) bonding agent for thicker or more opaque veneers.
• Etch the porcelain with hydrofluoric acid etchant.
• For bonding to the porcelain, use a silanating agent or appropriate ceramic primer.

Question 45

What are the simple rules for selecting which cement to use for leucite-reinforced restorations?

Answer 45

• Leucite-reinforced ceramics require resin cement bonded to both tooth structure and ceramic.
• Use dual-cured esthetic resin cement with a dual-cured total-etch (etch-and-rinse) bonding agent for thicker or more opaque veneers.
• For the tooth, use an adhesive resin cement or a dual-cured esthetic resin cement.
• Etch the ceramic with hydrofluoric acid etchant.
• For bonding to the ceramic, use a silanating agent or an appropriate ceramic primer.

Question 46

What are the simple rules for selecting which cement to use for lithium disilicate restorations?

Answer 46

• Lithium disilicate ceramics should be bonded with an esthetic resin or an adhesive resin cement for best retention and esthetics.
• Use a dual-cured esthetic resin cement with a dual-cured total-etch (etch-and-rinse) bonding agent for thicker or more opaque veneers.
• For bonding to tooth structure, use an adhesive resin cement or a dual-cured esthetic resin cement.
• Etch the ceramic with hydrofluoric acid etchant.
• For bonding to the ceramic, use a silanating agent or an appropriate ceramic primer.
• Lithium disilicate ceramics can be cemented with traditional crown and bridge cements when retention is adequate.

Question 47

What are the simple rules for selecting which cement to use for zirconia-based restorations?

Answer 47

• Zirconia-based ceramics with ideal retention can be cemented with traditional crown and bridge cements or bonded with resin cements.
• Zirconia-based ceramics with less than ideal retention require a resin cement bonded to both tooth structure and ceramic.
• Use adhesive resin cement, dual-cured esthetic resin cement, or self-adhesive resin cement when bonding is required.
• Sandblast (MicroEtcher IIA, Danville Materials) the intaglio surface of zirconia using 50 um alumina at 30 psi for increased bond strength.
• Use zirconia primer on the intaglio surface of zirconia when increased bonding is required.
• Silanating agents are not compatible with zirconia.
• Hydrofluoric acid is not compatible with zirconia.

Question 48

When should lithium disilicate and zirconia-based ceramic restorations be bonded?

Answer 48

Suitable for Cementation with Self-adhesive Resin Cement
• Tooth preparation with adequate cervical-occlusal height: h > 3 mm
• Tooth preparation with adequate taper: a = 2 – 5 degrees
Bonding with Adhesive Resin Cement or Esthetic Resin Cement
Recommended
• Tooth with short clinical crown: h 5 degrees
Note: Occlusal reduction of preparations for zirconia-based ceramics
• Non-functional cusps: > 2.0 mm • Functional cusps: > 2.5 mm