OP 1 Final Flashcards
shape of the preparation itself
outline form
What do these 4 factors establish?
- Access to the lesion (allows to visualize extent of caries and for burs to reach all carious lesions)
- Extent of the lesion (the extent of the caries in the dentin is what ULTIMATELY determines the preparation size)
- Restorative material to be used (ie amalgam or porcelain need a 90 degree cavosurface margin but composite or gold need a beveling of the margin)
- Esthetics
Outline form
T/F Outline form should be made so that occlusal contact NEVER hits the margin of the restoration
True
shape given to the prep to prevent fracture of either the restoration or the tooth
resistance form
What are these 3 things examples of?
- adequate bulking of amalgam
- rounding of internal line angles
- horizontal pulpal and gingival floors being prepared perpendicular to the tooth’s long axis
resistance form
Why is the prep placed 0.5 mm into the dentin?
- Avoid the sensitive DEJ
- Provide adequate bulk of restorative material
- Take advantage of the dentin’s resilient nature
What prevents fracture?
Resistance form
shape that prevents the restoration from being displaced by tipping or lifting forces
retention form
What are these 5 things examples of?
- undercuts
- truncations
- grooves
- pins
- dovetails
Retention form
What prevents displacement?
Retention form
What will come from converging walls, and sometimes the dovetail?
Primary retention
What helps retain the restoration in case the primary retention fails?
Secondary retention
What are these 11 things examples of?
- grooves
- coves
- extensions
- skirts
- beveled margins
- pins
- slots
- steps
- amalgam pins
- etchants
- adhesives
Secondary retention
What can also sometimes be considered a secondary retention factor?
Dovetails
shape that allows the needed procedure to be performed
convenience form
what allows for vision, access, etc. and is what influences the outline form itself?
convenience form
Why do amalgam preparations tend to have to have a few extra things done to them in order to be appropriate?
Amalgam does not directly adhere to the tooth
Because amalgam does not directly adhere to the tooth, what is usually necessary in order to maintain proper strength of amalgam restorations?
expansions of the prep
T/F Although dovetails are always beneficial on any preparation, they are VERY important for amalgam
True
What do amalgam preparations for class IIs require in order to minimize undermined enamel rods?
(while with composite, it is not necessary)
Reverse S curve
What is very vital in order to have maximal strength in amalgam restorations?
Compacting
T/F Amalgam does not need to be triturated to activate
FALSE, amalgam must be triturated in order to activate!!
T/F Amalgam cannot be added onto set amalgam and must be redone if necessary
True
Amalgam cannot be polished/finished until at least ____________ after placing placing (use _________ first and then ________; on slow speed); Has _______ tensile strength.
24 hours; brownie; greenie; low
T/F Composite preparations usually have a more conservative outline
True
What is NOT necessary for class II composite preps that is necessary for class II amalgam preps?
Reverse S curve
Axial wall retention grooves
What is the retention form in class II composite preps?
Converging walls (primary)
Adhesive system (secondary)
T/F Composite restorations tend to be weaker and are not the best choice for posterior teeth
True
What is more prevalent and can progress more rapidly in composite restorations?
Recurrent/secondary caries
What is the longevity of a composite restoration in comparison to an amalgam restoration?
1/2 the longevity of amalgam
What is necessary for composite, but NOT necessary for amalgam?
Etching
Curing light
T/F Composite CAN be added to composite unlike with amalgam, and finishing/ polishing can be done immediately with composite unlike amalgam
True
the process of curing monomers being converted from an aggregate of freely flowing molecules to a rigid assembly of cross-linked polymer chains
polymerization
What results in a substantial volume contraction during curing?
Polymerization
The higher the degree of conversion, the higher the ________________ _____________
polymerization shrinkage
The higher the ___________ ____________, the lower the polymerization shrinkage
filler content
Polymerization shrinkage with bonding can cause ___________ at the restorative interface. The more tension, the higher the likelihood of ____________ _____________
tensions; post-op sensitivity
Incremental placement of composite should be done __________ to avoid opposite walls in roughly _________ increments
obliquely; 2mm
What is the exception when it comes to recommended thickness of composite increments?
Box of a class II prep
(should be a roughly 1mm horizontal placement first before doing the standard oblique 2mm rule afterwards)
The interaction between two dissimilar metals and saliva; causes an electric shock to occur
Galvanic sensitivity/shock
A gold crown touching an amalgam restoration or aluminum foil touching amalgam
Galvanic sensitivity/shock
Pain, increased odds of restoration fracture AND/OR tooth fracture, increased sensitivity, periodontal issues around finished tooth, TMJ/TMD problems, root canal, unhappy patients
Clinical manifestations of hyperocclusion
Reasons for post-op sensitivity (6)
- Aggressive tooth preparation (ex: inadequate use of a cooling system, inefficient cutting instruments, & deep preps getting closer to more open dentinal tubules)
- Lack of adequate condensation of amalgam, ESPECIALLY with lateral condensation of proximal boxes
- Incorrect use of adhesive systems; ie using it for too long of a time (enamel and dentin have different etching times)
- Not using a liner or base when indicated
- Formation of microgaps from restoration shrinkage
- Aggressive finishing of restoration
Ways to prevent post-op sensitivity (3)
- Be mindful of the tooth preparation and the systems that you are using!! (for example, make sure to use etchants properly or a desensitizer solution after dentin acid etching)
- Add composite incrementally to reduce polymerization shrinkage
- Be careful with finishing/polishing restorations
T/F Traumatic occlusion is NOT an initiating factor, but can be a CONTRIBUTORY factor to periodontal disease
True
Trauma from occlusion has been linked to higher risk of what?
Furcation involvement
What is the main type of acid used in enamel etching?
Phosphoric acid (35-37%)
GI Conditioner is usually composed of what?
Polyacrylic acid
Composite curing is ________ activated, with dentistry using ______ light
light; blue
What occurs when light is placed on the composite?
Polymerization
Polymerization shrinkage related to bonded and unbonded surfaces follows what?
The cavity geometric configuration system, or C-factor
The higher the C-factor, the higher the __________
stresses
C-factor can be found by ?
Bound surfaces/unbound surfaces
What is the C factor in a class I?
5
What is the C factor in a class II?
2
What is the C factor in a class V or sealant?
0.2
Contraindications of resin (5)
- Allergy
- Replacement of cusps
- Large restorations on those with bruxism or where occlusal stress would be on restoration
- High caries risk (pt. noncompliance)
- When rubber dam isolation is not possible
Contraindications of amalgam (3)
- When esthetics are high priority
- Extensive destruction of tooth
- Cavity is small (leading to unnecessary removal of tooth structure)
Which material tends to show better results with posterior teeth regarding a longevity prognosis?
Amalgam
There is increasing evidence that properly accomplished posterior __________ ____________ restorations can be quite durable (up to 10 years)
resin composite
Etching time for cut enamel
15-30 seconds
Etching time for uncut enamel
45-60 seconds
Etching time for dentin
No more than 15 seconds
How long should you thoroughly rinse off etch?
10-20 seconds
How long should you dry the surface with an air blast after thoroughly rinsing off etch?
5 seconds or longer, if needed
What are you trying to accomplish when drying the surface with an air blast after thoroughly rinsing off etch?
Want to remove pooled water, but keep the dentin moist
(Do NOT overdry - collapse of collagen fibers can lead to suboptimal resin infiltration)
What is the purpose of etching?
To create microscopic roughness that increases surface area and potential for surface interactions with the bonding agent
What does etching cause specifically in dentin?
Dentin conditioning
Etching causing dentin conditioning, in which it exposes bundles of _________ that allows the primer to infiltrate and turn it into a __________ substrate
collagen; hydrophobic
What happens once dentin conditioning takes place?
Bond/resin can flow through the primed dentin and locked into place with curing
T/F Some amount of microleakage after placing a restoration is to always be expected
True
Small gaps or spaces that develop between the tooth and a restorative material.
This can allow things such as bacteria, fluids, molecules or ions to flow through if the space is large enough
Microleakage
What is the best way to reduce marginal leakage in amalgam restorations?
Proper condensation
What is the best way to reduce microleakage in composite restorations? (3)
- Proper application of bonding agents
- Proper preparation and cleaning of the tooth
- Incremental addition of material
What are the main reasons that microleakage occurs in composite restorations?
Polymerization process and shrinking
What is the most ideal contact angle of adhesive?
0 degrees
Smooth surface interproximal lesions are generally ___________ at the enamel surface and ____________ as it reaches dentin
wider; narrower
Pit/fissure lesions are ___________ at the enamel surface and __________ as they get towards the DEJ
narrower; wider
Caries affecting pits and fissures on occlusal 1/3 of molars and premolars, occlusal 2/3 of molars and premolars, and lingual part of anterior teeth
Class I
Caries affecting proximal surfaces of molars and premolars
Class II
Caries affecting proximal surfaces of central incisors, lateral incisors, and cuspids without involving the incisal angles
Class III
Caries affecting proximal including incisal angles of anterior teeth
Class IV
Caries affecting gingival 1/3 of facial or lingual surfaces of anterior and posterior teeth
Class V
Caries affecting cusp tips of molars, premolars, and cuspids
Class VI
Which caries classification is most and least common?
Most common = class I
Least common = class VI
Enamel rods tend to lead ___________ and flatten as you get ___________(and ultimately slightly leaning apically towards the very end)
coronally; gingivally
Occlusal preps need _____________ while with Class V preps you need slight ____________ (to prevent too much undermined enamel)
convergence; divergence
What does lateral expansion of decay mean?
When a carious lesion reaches the DEJ, it will rapidly spread in a lateral fashion across it
When do you use GI? (3)
- Class III restorations out of occlusion and do not pose esthetic concerns
- Pediatric dentistry
- Class V restorations that do not pose esthetic concerns
When do you use amalgam? Why?
Posterior-occlusal restorations due to high longevity and ability to withstand occlusal forces
When do you use composite?
- Restorations in esthetic regions
- Restorations that do not require large preps
What can be used as a liner/base, sealant, luting agent, or as a restorative material?
GI
What is the advantage of GI?
Releases fluoride and can be recharged
What are the disadvantages of GI?
Low flexural strength, compressive strength, and tensile strength
What is GI usually mixed with in order to have better longevity?
Resin
What does RDT stand for?
Remaining dentin thickness
What is the MOST important factor in maintaining pulpal health?
RDT (remaining dentin thickness)
Why is RDT the most important factor in maintaining pulpal health?
Dentin has a very good buffering capacity (so no more than necessary should be removed!)
The larger the RDT, the less likelihood of …
bacteria reaching the pulp
What does ZOE stand for?
Zinc oxide eugenol
What is ZOE used as?
A base in pulpal protection procedures
ZOE is a _______ strength and _________ solubility base
low; high
What can ZOE be used for?
Indirect pulp capping under amalgam or GI
T/F ZOE can have occlusal contacts as a sedative restoration
FALSE
What material can be left as a base if the tooth is asymptomatic for 14 days and be restored over with amalgam or GI?
ZOE
T/F ZOE can be used under composite restorations
FALSE, it can NEVER be used under composite!!!
Can ZOE be used in conjunction with adhesive dentistry?
NO
Can ZOE be used a first layer for direct pulp capping?
NO, it can only be used for indirect pulp capping!
What material is a liner used to assist in reparative dentin formation?
Dycal
How should Dycal be applied?
In a very thin layer, less than 0.5 mm
When is Dycal NOT needed?
- When secondary dentin is present
- Sclerotic changes have occurred
When is Dycal needed?
- When you are within 1mm of pulp chamber
- When a pulp exposure has occurred
- When a pulp exposure has possibly occurred (pink dentin)
T/F Dycal is a weak material and must be covered with a stronger material such as GI
True
What is the most accepted theory of pain transmission?
Hydrodynamic theory
What are dentinal tubules filled with?
Odontoblastic processes and dental fluid
Small fluid movements arising from cutting, drying, pressure changes, osmotic shifts, or temperature changes distort odontoblasts and stimulate nerves
Hydrodynamic theory
When are some clinical examples of when temporary restorations are needed? (6)
- Emergency patients when there is limited time
- When a restoration is needed, but will need removal soon for additional procedures to be done (such as with a root canal)
- Temporary crown to wear while final crown is being made
- Displaced crown with post/core
- Trauma including pulp exposure
- Fractured posterior tooth
What can be used to maintain space and occlusal relationships?
Interim partial/complete dentures
What are some functions of temporary restorations? (8)
- Protect enamel, dentin, and pulp
- Protect gingiva
- Protect soft tissues
- Protect margins
- Prevent drifting/tilting/movement
- Maintain occlusal relationships
- Maintain esthetics
- Reduce sensitivity
What has a positive influence on tooth structure when given at low doses?
Fluoride
Prior to tooth eruption, __________ can be incorporated as __________during the mineralization process
fluoride; fluorapatite
Hypomineralization of enamel
Fluorosis (too much fluoride)
As a topical treatment, fluoride has a ________ uptake by the tooth and helps to __________ demineralization and ___________ remineralization
rapid; inhibit; promote
What kind of enamel is more resistant to decay?
Remineralized enamel
Why is remineralized enamel more resistant to decay? (4)
- Has larger crystals with higher amounts of fluoride
- Interferes with microorganisms
- Reduces solubility of enamel
- Seals dentinal tubules to alleviate hypersensitivity
Fluoride is __________ in high concentrations
bactericidal
What are the reasons for fractured restorations and teeth? (6)
- Restoration has high contact
- Margins/walls are not 90 degrees to tooth
- Pulpal floor is not deep enough
- Internal angles are not slightly rounded
- Buccal/lingual walls are not converging
- Incorrect/insufficient condensing of amalgam (if applicable)
Where is the location of decay in contact areas?
ALWAYS just apical to the interproximal contact point
Features that are necessary for all preps regardless of outlines
Primary retention features
What are the primary retention features of an amalgam prep?
- Converging walls
- Retention grooves (if needed)
What are the primary retention features of a composite prep?
Converging walls
What feature is considered primary retention if it is a part of buccal/lingual grooves?
Dovetails
Caries formula
Sugar + bacteria = decrease in pH/increase in acidity
Acidity causes tooth decay if high enough
Dental caries are a ___________ disease
site-specific
What bacteria are caries linked to?
S. mutans
Process of removing surface defects or scratches created during the contouring process using cutting or grinding instruments
Finishing
Most refined of the finishing processes, removing the finest surface particle
Polishing
Which alloy?
Disadvantages = requires a higher mercury amount, needs early condensation with a small condenser, and needs higher packing forces during condensation
Lathe-cut
Which alloy?
Advantages = high positive pack handling quality to provide good proximal contacts (it is crunchier) and it causes minimal material-related post-operative sensitivity.
Lathe-cut
Which alloy?
Disadvantages = requires a larger condenser, has a shorter working time (BUT it leads to a higher early strength so that aspect can be an advantage), no positive pack capability (poorer contacts and more overhangs) and there is a greater risk of post-operative sensitivity
Spherical alloy
Which alloy?
Advantages= requires a lower condensation pressure to achieve the same strength.
Spherical alloy
Which alloy needs a varnish or alternative dentin sealer and greater burnishing?
Spherical alloy
Which alloy is typically only good for amalgam cores or places where lower condensation forces are preferred?
Spherical alloy
Which alloy is a mixture of both the lathe-cut and spherical types of amalgam and combines the best of both geometries?
Admixed alloy
Which alloy has high packing pressures with small condensers still being required, but obtains positive interproximal contacts?
Admixed alloy
Which alloy has a slightly faster setting time and low post-operative sensitivity?
Admixed alloy
