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74 Cards in this Set
- Front
- Back
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What are the advantages / disadvantages to an AMALGAM cast-post-core?
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ADV:
- conservative of tooth structure - straightforward technique DIS: - low-tensile strength - corrosion with base metal |
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AMALGAM Cast-post-cores are recommended on which teeth generally?
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- molars with adequate coronal tooth structure
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What are the advantages / disadvantages to an GLASS IONOMER cast-post-core?
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ADV:
- conservative of tooth structure - straightforward technique DIS: - low strength - difficult condensation |
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What are the indications to use GLASSIONOMER or COMPOSITE cast post cores?
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- teeth with minimum tooth structure missing.
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What are the advantages / disadvantages to a CUSTOM cast-post-core?
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ADV:
- high strength - better fit than prefab DIS: - less stiff than wrought wire - time consuming, complex procedure |
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What are the indications for CUSTOM CPC?
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- elliptical or flared canals
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Which teeth generally have CIRCULAR canals?
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- maxillary CENTRAL INCISORS
- maxillary FIRST PREMOLAR (two roots) - mandibular second premolar - maxillary molars (distobuccal roots) |
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Which teeth generally have MESIODISTAL ELLIPTICAL canals?
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- maxillary molars (palatal roots)
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Summarize the steps for inserting PREFABRICATED POST:
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1. enlarge canal one or two sizes with a drill/endo file/ or reamer than matches configuration of post
2. Use prefabricated post that matches drill size. 3. Do not remove excessive apical structure |
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Summarize the steps for CUSTOM MADE POST / DIRECT PROCEDURE:
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1. lightly lubricate the canal and notch a loose fitting dowel - should extend to full depth of canal
2. use bead-brush technique to add resin to the dowel and seat it in the prepared canal (first add resin to canal orifice) 3. Do not allow resin to fully harden within the canal. loosen and repeat several times while still rubbery 4. Once resin has polymerized remove the pattern 5. form the apical part of the post by adding additional resin and reseating and removing (make sure it doesn't lock in the canal 6. identify any undercuts that can be trimmed away carefully with a scalpel. POST PATTERN MUST BE INSERTED AND REMOVED EASILY WITHOUT BINDIND IN THE CANAL |
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Summarize the steps for CUSTOM MADE POST / INDIRECT PROCEDURE:
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1. Cut piece of ortho wire / paper clip to length and shape like a J
2. Verify the fit of the wire in each canal - should be loose and fit to the FULL depth of the canal. It SHOULD NOT fit tightly 3. Coat the wire with tray adhesive, Lubricate the canals to facilitate removal of impression material 4. Using lentulo spiral - fill canals with elastomeric impression material (MUST SPIRAL CLOCKWISE). Pick up small amount of material with largest lentulo that will fit into canal. Insert first at a LOW ROTATION SPEED, then INCREASE the speed while withdrawing the lentulo from the post space - this avoids material being dragged out of canal. REPEAT until post space is filled. 5. Seat wire reinforcement to the full depth of each post space, syringe in more impression material around the prepared teeth, and insert the impression tray 6. Remove the impression, evaluate it, and pour the working cast as usual |
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Summarize the step-by-step procedure for creating an AMALGAM CORE:
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1. Apply rubber dam, remove gutta percha, leave approx. 5mm of apical GP.
2. Remove any existing restoration, undermined enamel, or carious/weakened dentin. Establish cavity form using conventional principles or resistance and retention. PINS ARE NOT REQUIRED. 3. Protect pulpal floor with cement base if you suspect it being thin. 4. Fit a matrix band. 5. Condense first increments of amalgam into the root canals with an endodontic plugger 6. Fill the pulp chamber and coronal cavity in the conventional manner 7. Carve the alloy to shape, impression can be made immediatley. Alternatively, the amalgam can be built up to the anatomic contour and later prepared for a complete crown. |
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Summarize the step-by-step procedure for creating CAST METAL CORE / Direct Procedure for Single-rooted teeth:
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1. use pre-fab or custom resin post
2. Add resin by the "bead" technique, dipping a small brush in monomer and then into polymer and applying it to the post. 3. Slightly overbuild the core and let it polymerize fully 4. Shape the core with carbide finishing burs or paper disks. Use water spray to prevent overheating of acrylic resin 5. Remove the pattern, sprue and invest immediately. |
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Summerize the step-by-step procedure for creating CAST METAL CORE / Direct Procedure for Multi-Rooted Teeth:
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1. Fit pre-fab posts into the prepared canals - one is roughened the others are left smooth and lubricated. All posts should extend beyond eventual preparation
2. Build up core with autopolymerizing resin 3. Shape the core to final form with carbide burs 4. Grip the smooth, lubricated posts with forceps and remove them 5. Remove, invest, and cast the core with the roughened single post. 6. After verifying fit at try-in, cement the core and auxillary posts to place |
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Summarize the step-by-step procedure for creating CAST METAL CORE / Indirect Pattern for Posterior Teeth
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1. Wax the custom made posts as described previously
2. Build part of the core around the first post 3. Remove any undercuts adjacent to the otehr post holes and cast the first section 4. Wax additional sections and cast them. |
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What is the MINIMUM thickness of remaining tooth structure that should be kept during Cast-post-core procedures?
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1 mm
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What are the two CONTROLLED REDUCTION techniques?
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TROUGHS
SELECTIVE INSTRUMENTATION |
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What is TYPE I metal used for?
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Simple inlays
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What is TYPE II metal used for?
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Complex Inlays
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What is TYPE III metal used for?
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Crowns and fixed partial dentures (Bridges)
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What is TYPE IV metal used for?
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Removeable Partial Dentures
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What are the three classes of CAST DENTAL ALLOYS:
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High noble - min 60% noble and 40% gold
Noble - min 25% noble, and less than 40% gold Base - less than 25% noble, includes nickel/ chromium |
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What are the principal goals of cementation?
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- retention of prosthesis
- sealing (elimination of microleakage) |
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What are the IDEAL PROPERTIES of DENTAL CEMENTS?
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1) WORKING TIME should be adequate to allow proper mixing, loading, and seating of restoration
2) SETTING TIME should be rapid after proper positioning 3) MANIPULATION - low technique sensitivity so that slight deviation of ideal condition or handling will not critically affect result 4) FILM THICKNESS should be less than 30 microns 5) BONDING/ADHERENCE to tooth structure and restorative material 6) SOLUBILITY should be low in water and resistant to acid attack 7) COMPRESSIVE and tensile strength should be high 8) THERMAL INSULATION when used as a base 9) PULPAL RESPONSE should be low, biocompatible, possible obtundant 10) FLUORIDE RELEASING thought to be anti-cariogenic 11) COLOUR should be transparent or tooth-coloured for esthetic demands 12) EASE OF CLEANING adherence to tooth, soft tissue, and restoration impedes post-cementation cleanup |
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What is one DISADVANTAGE of tooth coloured cements?
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- difficult to identify during cleanup
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Define MODULUS OF ELASTICITY:
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resistance to plastic deformation under high load
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COMPRESSIVE/TENSILE:
What is the STRONGEST to WEAKEST list of cements? |
- resin
- resin reinforced GIC/GIC - Zinc phosphate - polycarboxylate |
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BOND STRENGTH:
What is the STRONGEST to WEAKEST list of cements? |
- resin
- polycarboxylate - resin reinforced GIC - zinc phosphate - GIC |
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What will increased film thickness limit?
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seating
marginal adaptation |
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FILM THICKNESS:
List SMALLEST to LARGEST of the cements? |
- resin reinforced GIC
- GIC - zinc phosphate - resin |
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Post-cementation thermal sensitivity has been reported for which cements?
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- Zinc phosphate
- GIC |
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Why do Zinc Phosphate and GIC sometimes have post-cementation sensitivity?
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- low pH at initial mixing
- microleakage? |
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What is the composition of Zinc phosphate cement?
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Zinc oxide
+ MgO + Phosphoric acid |
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What are the ADVANTAGES of ZINC PHOSPHATE cement?
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- long track record
- good physical properties - predictable, high rigidity (MOE) - easy to remove set material |
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What are the DISADVANTAGES of ZINC PHOSPHATE cement?
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- no bond to tooth/restoration
- incidence of tooth sensitivity - increased microleakage compared to other cements |
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How can working time be extended for ZINC PHOSPHATE cement?
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- incremental mixing
- cooled slab |
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What are the recommendations for ZINC PHOSPHATE cement use?
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- good general purpose
- conventional crowns - posts with retentive preparations |
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What is the composition of ZINC POLYCARBOXYLATE cement?
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- polyacrylic acid
- zinc oxide - polycarboxylate acid |
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What are the ADVANTAGES of ZINC POLYCARBOXYLATE cement?
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- bonds enamel and dentine
- reasonable track record - good working characteristics - good biocompatibility - kind to the pulp (near neutral pH) |
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What are the DISADVANTAGES of ZINC POLYCARBOXYLATE cement?
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- low rigidity - can deform under pressure
- low tensile strength - difficult to remove excess |
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What is the recommendation of use for ZINC POLYCARBOXYLATE cement?
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- retention of long-term PROVISIONAL crowns or short term provisional crowns if PREPARATION IS UN-RETENTIVE
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What is an example of ZINC POLYCARBOXYLATE cement?
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Poly-F Plus
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What are some examples of GIC cement?
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- Fuji I, Ketac-Cem
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What is the composition of GIC cement?
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- polyacrylic italmic acid copolymer
- calcium fluoroaluminosilicate glass |
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What are the ADVANTAGES of GIC cement?
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- low chemical bond to tooth
- high fluoride release - good compressive strength (low MOE) - low solubility - low film thickness |
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What are the DISADVANTAGES of GIC cement?
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- moisture sensitive techniques
- high solubility in first 24 hours - difficult to protect margins from moisture contamination - over-drying may cause sensitivity - time required to develop maximum strength - low MOE |
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What are some clinical steps for using GIC cement?
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- clean with flour of pumice and isolate tooth
- do not over dry - if dry, moisten with cotton rolls - clean cement after final setting |
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What is the recommended use of GIC cement?
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- general purpose
- conventional crown and bridge work |
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What are some examples of RESIN MODIFIED GIC cement?
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- FUJI Plus
- Rely X |
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What are the ADVANTAGES of RESIN MODIFIED GIC CEMENT?
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- fluoride release
- excellent physical properties - medium - high strength - low chemical and micromechanical bond to tooth - insoluble |
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What are the DISADVANTAGES of RESIN MODIFIED GIC cement?
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- moisture sensitive techniques
- excess material at margin may be difficult to remove - less soluble than GIC in first 24 hours - over drying causes sensitivity - possible cement expansion - shorter clinical track record |
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What are some choices for ESTHETIC RESIN cements/
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- Choice 2 veneer cement
- Rely X veneer cement |
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What are the ADVANTAGES of ESTHETIC RESIN CEMENT?
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- high strength
- insoluble - excellent bond to tooth with etching procedures - good bond to etched metal and silanated ceramic - inhbiits crack formation and progression in ceramic restorations - available as dual cure or light cure |
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What are the DISADVANTAGES of ESTHETIC RESIN CEMENT?
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- multiple steps
- moisture sensitive techniques - possible sensitization to polymerization shrinkage - little to no fluoride release - increased film thickness - dual core may not be completely set in thick areas |
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What are the ADVANTAGES of ADHESIVE RESIN CEMENT?
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- good bond to etched metal and tooth
- high strength - insoluble |
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WHat are the DISADVANTAGES of ADHESIVE RESIN CEMENT?
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- multiple steps
- moisture sensitive techniques - little to no fluoride release - increased film thickness - some anaerobically setting cements (ie PANAVIA) may set too quickly in endodontic canals preventing seating of post |
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What are the ideal requirements of TEMPORARY CEMENTS?
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- should retain the restoration while providing good seal and low sensitivity
- should have low bond strength to allow easy removal - should have reasonable setting time |
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What are the different kinds of TEMPORARY CEMENTS?
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- Zinc oxide eugenol
- non-eugenol Zinc oxide - Resin - zinc polycarboxylate |
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What is the PRIMARY SOURCE of colour of a tooth?
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Dentin
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WHat are the THREE COMPONENTS of colour?
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VALUE - luminosity / brightness, most influential
CHROMA - saturation / intensity HUE - colour itself |
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Which portion of the crown is the BRIGHTEST?
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- middle third
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Which portion of the crown is the LEAST BRIGHT?
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Incisal third
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How do mandibular incisors shade compare to that of maxillary?
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Mand incisors usually one shade lighter than max
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How do CANINES shade compare to that of other teeth?
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Usually canines are one or two shades darker than maxillary incisors
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Define METARMERISM:
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- two colours that appear to be a match under a given lighting condition but have different spectral reflectance are called metamers, and the phenomen is known as metamerism
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How does one avoid the problem of METAMERISM?
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- select shade and confirm it under different lighting conditions
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What is the SEQUENCE of SHADE SELECTION?
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- determine HUE
- determine CHROMA - determine VALUE - determine METAMERIC EFFECT |
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What are the different HUES of the SHADE GUIDE?
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A: brownish tones
B: yellowish tones C: grey tones D: reddish tones |
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Which tooth generally has the most saturation of colour (hue) ?
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- CANINES
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What does the SQUINT test help with?
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Enhances ability to select VALUE
Decrease ability to see HUE |
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How does one perform the squint test in shade matching?
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Observer concentrates on which colour disappears from sight first - tooth or shade tab. The one that FADES FIRST has the lower value.
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Which type of light is the most critical of all lighting for revealing metameric changes in colours?
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Subdued tungsten light
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What are the GENERAL PRINCIPLES in SHADE SELECTION?
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1) Use shade guide that matches type of porcelain that is used
2) Patient should be viewed at eye level 3) Shade comparison should be made under different lighting conditions to reduce metameric effect, 4) preferably at the START of the appointment while tooth is still wet 5) teeth should be clean, remove calculus and stain by prophy 6) distracting, brightly coloured lipstick should be removed 7) make shade selection initially with tooth and guide dry 8) shade selection should be made QUICKLY to avoid colour fatigue 9) concentrate on MIDDLE THIRD of the tooth 10) ideally use a second shade guide for value only 11) make a drawing of a tooth for prescription - |
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How can one "reset" the eyes after colour fatigue?
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Rest eyes on a grey surface to balance receptors
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