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60 terms

jp2014 RESD521_midterm

Advantages of the Class 2 Amalgam restoration
- longterm restoration (10-20 years)
- Can be placed quickly and easily
- Conservative preparation - less cutting than an inlay/onlay
- Short term low cost
Disadvantages for the Class 2 Amalgam restoration:
- material corrodes and tarnishes
- low tensile strength - can fracture at isthmus and at margins
- poor esthetics - color is wrong; limited to posterior teeth
- difficult to manage occlusion and contours
Retentive features for the Class 2 Amalgam MO cavity preparation:
- occlusal dovetail
- converging approximal walls
- parallel or converging occlusal walls
- pyramidal undercuts in the dentin of the facial and lingual proximal walls
- acute axiogingival line angles
Indications for the use of the Class 2 Amalgam:
- primary molar teeth
- cheap
- disease control in caries ravaged posterior dentition
- routing restoration for posterior approximal lesions
- build-ups for more extensive restorations
Contraindications for Class 2 Amalgam:
- esthetics
- undermined cusps
Describe Instrumentation of Class 2 cavity prep for Amalgam:
- Matrix
- Function - to contain the amalgam in a stable form during condensation
- Requirements - smooth surface, stability, control contours and contact area, convenient to apply and remove
- Toffelmire system:
- Advantage - fast and easy
- Disadvantage - poor proximal contours, must pass through both contacts and contacts not restored, tension on the tooth
Extra Information session1:
- Enamel on gingival wall needs a slight 20 degree bevel
- Finishing and Polishing Surface Removal
- Decreases corrosion and tarnish
- Decreases hot/cold sensitivity
- Makes it easier for patient to clean
- Redefine anatomy and margins
- Abrasive Action: Particle Shape, Hardness, Load, Direction, Speed
Advantages of the Class 2 Composite restoration:
- strength of the restored tooth is improved; cusps are bonded together
- Minimal tooth reduction required; bonding aids retention
- No thermal or galvanic reactions
- Early strength and wear resistance is good
- Bonding agents decrease sensitivity and prevent microleakage
- Color is good and stable
- Materials are radiopaque
Disadvantages of the Class 2 Composite restoration:
- Extremely technique sensitive. Takes considerable time for placement
- Sometimes post-op sensitivity
- Proximal contours are difficult to achieve. Poor contact areas
- Wear and durability have been questioned
- Not used for heavy occlusion
Cavity Prep for Class 1 and 2 Composite Restoration different from Amalgam
- Pumice and clean teeth; select shade; place rubber dam
- Prepare class 2 cavity
- Rounded internal line angles
- Bevels occlusal and gingival
- If liner is needed; place Dycal and Vitrebond (glass ionomer liner)
- Apply All-Etch 32% H3PO4 to cavity for 30 seconds, rinse
- Apply Primer A + B over cavity; 3-5 coats; appears glossy; dry
- Place Dentin/Enamel Bonding Resin (thin), cure 20 sec.
- Place Matrix and Wedge for separation
- Place increments of composite; cure 40 sec./incr
- Remove matrix and contour with discs, finishing burs. Wash
- Etch surface 15 sec. rinse, dry
- Apply Primer A + B 2-3 coats
- Place Fortify Cure 20 sec.
Matrix application for Class 2 Composite Restoration
- wedge from lingual
Insertion, Cure, and Finish of Class 2 Composite Restoration
- wedge from lingual
Extra Information session 2:
- Slight enamel bevel 20 degrees on gingival cavosurface margin
- Cause of Fracture and Recurrent Decay
- Only cured for 20 seconds
- Too high and fractured
- Puddle of bonding agent left a void
- Wedged used for:
- Push down gingivae
- Separate teeth
- Secure matrix band
Video: Class 2 Composite Disadvantages:
- Open contact
- Curved Contour
- Voids in proximal box
- Finishing of occlusal
RMGI (Vitrebond) used for:
- filling material
- gingival decay
- Recession
- Fluoride release
- Decrease sensitivity
- Make a prep look better (gain draw, proper form)
- Expands and contracts with tooth
Features for an Ideal Composite Restorative Material:
- Excellent Physical properties
- High-gloss polishability
- Fracture resistance
- Color stability
- Universal usage
- Radiopacity
- Extensive shade range
- Ease of handling
- High viscosity
- Clinically proven
Ideal Bonding System (the de-dedeh ones)
- high bond strength
- bond to wet surface
- bio-compatible
- total seal of dentin tubules
- self or dual cure
Custom Matrix System:
- Advantage
- Superior contour and contact
- Greater stability
- Greater adaptability
- Less stress o the tooth
- Disadvantage
- More time involved
What is maximum thickness of each resin increment in Class 2?
2 mm
Where does polymerization shrinkage begin in photoinitiated resin restorations?
Margin? Therefore use fortify to preserve marginal integrity
How thick is the smear layer on dentin?
10-15 microns
What is the % shrinkage that occurs in photoinitiated resin restorations? If the surface area is 1.0 mm, how much contraction gap is likely to occur?
2%; 0.02 mm
What is the maximum isthmus width for Class 2 composite restorations?
1.0 mm, 0.5 mm clearance
If the gingival wall in a Class 2 composite preparation is solely on dentin, what is the best way to manage the gingival wall prior to placement of the composite material?
Dentin must be kept moist for ALL-BOND 2. If close to pulp, Dycal should be applied to the area nearest the pulp
Describe "pre-wedging" for Class 2 composite restorations.
Wedge before placement of a matrix to insure tighter contacts.
What are the causative factors for small voids appearing on the surface during finishing?
Lack of incremental curing?
Principles for Class 3 Composite preps:
- Approach from Lingual
- Protect incisal angle of tooth
- Preserve the facial plate of enamel
Class 3
Must have retentive grooves (1/4 round bur)
Class 4
Axial wall should be 1.5 mm in length
Problems with using Pins in Class 4:
- Stain
- Porosity
- Leakage
Article: Initial Preparations for Amalgam Restorations
- Outline: only include caries
- Narrow the outline more longer the life and less marginal deterioration
- Blah blah blah
- Class 2 "slot type" preparation is used for approximal caries and to conserve tooth structure; retentive grooves must be placed
- Only cut where there is caries
Article: Overcoming the challenges of Class II resin-based composites
- Resin-based composites (RBCs)
- Amalgam will end for Class Restorations, RBCs win!
- Problems:
- Proximal Contacts
- Postoperative Tooth Sensitivity
- Endodontic "boom" due to pulpal death caused by Class I and II
- Self-etching primers obdurate canals and decrease post-op sensitivitiy
- GLUMA Desensitizer eliminate post-op sensitivity
- RMGI Liner (Vitrebond) eliminates post-op sensitivity
- Preventing the "white line" due to 2% polymerization shrinkage adding stress on the bonded cusps by curing in increments and proper finishing
- Use Loupes
- Sharp Burs: 7406 occlusal, 7901 gingival overhangs, 7801 occlusal grooves
- Low speed and light pressure
- Optimum vision with NO water spray
- Avoid tooth trauma
- Challenges to overcome:
- Lower polymerization shrinkage to below 1%
- Flowable is 6%
- Match the wear resistance of RBCs to enamel
- Lead to fracture and TMJ problems
Article: Abfraction; A solution to the enigma?
- Def: solitary non-carious cervical lesions in posterior teeth resulting from undermined enamel and eccentric forces on teeth
- 3 Causes of Abfraction:
- Attrition: the physiolocigc wearing away of tooth substance
- Erosion: loss of tooth from acid dissolution
- Abrasion: tooth structure destruction resulting from mechanical means
- NOT due to brushing; know physical characteristics of enamel and dentin AND forces generated during function
- Enamel
- Cervical 1/3: prisms horizontal
- Occlusal 2/3: prisms almost vertical
- Prisms resist fracture under compression
- Dentin
- Resilient to tensile forces but not compressive
- 3 Main stresses in occlusion
- Compressive (vertical), shear (sliding/twisting), tensile (stretch)
- Def: "pathological loss of hard tissue substance caused by biomechanical loading forces. These lesions are due to flexure and ultimate fatigue of enamel and dentin at a location away from the point of loading."
- Abnormal forces = tensile and compressive forces
- Ie contact on buccal slope of mandibular lingual cusp - tooth "bends" towards lingual - enamel rods compress lingual surface and tensile stress on buccal surface - tensile stressed concentrate at CEJ - create stain on bonds in inorganic matrix b/w enamel rods - susceptible to other non-carious breakdown (erosion, abrasion, attrition)
- "frictional ablation" = soft tissue hyperactivity creates a frictional wear on oral hard tissues
- Most common site for abfraction is Premolars (Mx and Md)
- Due to differences in composition and flexure, v-shaped lesions occur in dentin at the cervical margin; enamel range from hairline cracks to semilunar shape to cusp tip invagination
Procedure steps for class 2 amalgram
1. pumice and clean tooth; check occlusionm place rubber dam
2. prepare class 2 cavity
3. if base is needed; place dycal; fuji 2 glass ionomer liner/vitrebond; cure
4. place primer A-B over dentin and enamel
5. place matrix; wedge
6. insert and condense amalgam; precarve burnish optional
7. remove matrix; carve anatomy
8. after carve burnish
9. remove rubber dam; clean sulcus
10. check and adjust occlusion
11. polish after 4 hrs
enamel hatchet
for finish occlusal
(disk for proximal)
Depth of cavity
right angle
buccal (upper)
lingual (lower)
Protecting marginal ridge
gingival bevel
20 degree
Principles of cavity prep
1. outline form
2. resistance form
3. retention form
4. convenience form
5. remove decay
6. enamel finish
7. clean cavity
finish and polish (advantages)
1. decrease corrosion and tarnish
2. decrease hot/cold sensitivity
3. make it easier for patient to clean
4. redefine anatomy and margins
Abrasive action
particle shape
particle hardness
particle load
particle direction
particle speed
245, 329 pear shaped bur
open prep; pulpal and gingival
168 taper fissure bur
occlusal fissures; axial wall, retnetive groove
width of a 21 hoe
width of a 23 hoe
temp of mixing zinc phosphate
allbond 2 primer penetrates what?
intertubular and peritubular
white line of a class 5 is due to
gap contraction
class 5 retention
opposing gingival and occlusal wall
bonding agent
why belvel a class I inlay?
remove enamel rod
adapt gold margins
angle of floor to wall in an inlay (class I)
GI advantages
Fluoride release
bond to tooth
same thermal expansion as enamel
Unused resin
surface sealant
bonding agent
mixture of particle sizes
type of resin-based composites
flowable microfill
flowable nanofill
flowable microhybrid