Operative Flashcards
Carbonate substitution_________ solubility of
hydroxyapatite
increases- easier to decay.
Critical pH
* Enamel (FA)
* Enamel (CHA)
* Dentin and Cementum
- Enamel (FA)= 4.5
- Enamel (CHA)= 5.5
- Dentin and Cementum= 6.2-6.7
- Root-surface lesions progresses slowly or rapidly?
Rapidly because no enamel
Shapes of
* Pit and fissure lesions
* Smooth-surface lesions
- Pit and fissure lesions à inverted V-shape
- Smooth-surface lesions à V-shaped
- Infected dentin
- Affected dentin
- Infected dentin= superficial, wet, soft, mushy, necrotic
- Affected dentin= deeper, dry, leathery, demineralized but not invaded by bacteria
Requires _________ surface for remineralisation
intact
occurs at junction of tooth and restoration indicating microleakage
Secondary/Recurrent
caries that remain in a completed tooth prep
Residual caries
Bacteria
* Enamel caries
* Dentinal caries
* Root caries
- Streptococcus mutans -enamel caries
- Lactobacillus - dentinal caries
- Actinomyces- root caries
rapidly damages tooth structure, light-colored, soft, infectious
Acute or rampant caries
brown/black, hard, caries-resistant if exposed to fluoride (dentinal lesion has sclerotic dentin)
Arrested caries
Tooth needs ______% mineral loss to be detected radiographically
30-40%
In transillumination Shadows can indicate
interproximal caries
Marginal gap or ditching _________mm is judged carious or
caries-prone
> 0.5 mm
loss of tooth structure by mechanical wear
Abrasion
occlusal wear from functional contacts with
opposing natural teeth
Attrition
Treatment Plan Sequencing and functions
- Urgent phase= acute infection, pain, swelling
- Control phase= caries, oral hygiene
- Reevaluation phase
- Definitive phase= ortho, prosth, surgery
- Maintenance phase
Rx for incipient smooth-surface lesions
Remineralisation
Rx for pits and fissures
sealents
Functions
– Scalers
– Excavators
– Chisels
– Other
– Scalers - Calculus
– Excavators - Dentin
– Chisels - Enamel
– Other - Restoration
Sickle scaler
Curette
Sickle scaler= supragingival calculus
Curette= subgingival calculus
Rotary Instruments
* Low-speed handpiece ______ rpm
– ____ bur for safe caries removal
* Medium-speed handpiece ____rpm
* High-speed handpiece___ rpm
- Low-speed handpiece
– <12,000 rpm
– Large round bur for safe
caries removal - Medium-speed handpiece
– 12,000-200,000 rpm - High-speed handpiece
– >200,000 rpm
- Carbide
– Better for ____cutting
– Produce _______ heat - Diamond
– Better for ____cutting
– Produce ________ heat
– ________ hardness
- Carbide
– Better for end-cutting
– Produce lower heat - Diamond
– Better for side-cutting
– Produce higher heat
– Greater hardness
cutting= __________blades
* Finishing= ________ blades
* Fine finishing= ______blades
* Ultra fine finishing= _________blades
cutting= 6 blades
* Finishing= 12 blades
* Fine finishing= 18-24 blades
* Ultra fine finishing= 30-40 blades
- 245
– ________ mm
– ________shaped - 330
– _________ mm
– _________shaped
– Smaller size is helpful for ______
preparations - 169L
– shape?
- 245
– 3 mm x 0.8 mm
– Pear-shaped - 330
– 1.5 mm x 0.8 mm
– Pear-shaped
– Smaller size is helpful for pediatric
preparations - 169L
– Tapered fissure
Outline Form
initial depth of _____mm into dentin
Extend gingival floor to get ____mm clearance
* Extend facial and lingual proximal walls to get ________mm clearance
initial depth of 0.2mm into dentin
Extend gingival floor to get 0.5mm clearance
* Extend facial and lingual proximal walls to get 0.5mm clearance
Demineralised enamel is called
undermined enamel is called
Friable
Unsupported
________ enamel need to be removed because bonding agent may not be effective
Friable
Primary resistance features
Flat pulpal and gingival floor
rounded internal line angles
Primary Retention Form
Convergent
* Dovetail
- Convergent walls prevent _______ displacement
- Dovetail prevents _________displacement
- Convergent walls prevent occlusal displacement
- Dovetail prevents proximal displacement
GLUMA Composition
GLUMA
– 5% glutaraldehyde
– 35% HEMA (hydroxyethyl
methacrylate)
– Water
Liner include
CaOH or RMGI
Liner uses
- Used for direct or near pulp exposures
- Provides a barrier to protect dentin from residual reactants of
restoration and oral fluids - Electrical insulation
- Thermal protection
- Pulpal treatment (formation of tertiary dentin)
Base includes
RMGI or GI cement
Base uses
- Used for metal restorations
and when liner is used - Thermal protection
(especially under amalgam
and gold) - Distributes local stress
across all underlying dentin
Remaining Dentin Thickness
* Amalgam
– ≥2mm
– 0.5-2mm
– <0.5mm
* Composite
– ≥0.5mm
– <0.5mm
* Gold or Ceramic
– ≥2mm
– 0.5-2mm
– <0.5mm
- Amalgam
– ≥2mm sealer
– 0.5-2mm base, sealer
– <0.5mm liner, base, sealer - Composite
– ≥0.5mm bond
– <0.5mm liner, base, bond - Gold or Ceramic
– ≥2mm cement
– 0.5-2mm cement (2mm thick)
– <0.5mm liner, base, cement
Secondary Resistance and
Retention Form
- Retentive grooves
- Beveled enamel margins
- Slots
- Pins
- Slots
– At least ____ mmdeep
– At least ____mm long
– ________mm inside DEJ - Pins
– _________ pin most
common
– Usually where a _________l wall is
missing
- Slots
– At least 1mm deep
– At least 1mm long
– 0.5mm inside DEJ - Pins
– Self-threaded pin most
common
– Usually where a vertical wall is
missing
Amalgam Preparation bur
Composite Preparation bur
Use a carbide bur for smooth walls
Use a coarse diamond for rough walls
- Collar
- Skirt
- Provide _________ R&R form
- Collar= beveled shoulder around capped cusp for bracing
- Skirt= feather-edge margin
- Provide secondary R&R form
Amalgam composition
50% mercury
50% metal alloy
* Silver
* Tin
* Copper
* Zinc
uses
* Silver
* Tin
* Copper
* Zinc
- Silver à strength
- Tin à corrosion
- Copper à strength
- Zinc à deoxidizer, but excess expansion if moisture
contamination
Trituration phases
* γ=
* γ1=
* γ2=
- γ= unreacted silver-tin
- γ1= strong silver-mercury matrix
- γ2= weak tin-mercury
- Normal mix=
- Over-trituration=
- Under-trituration=
- Normal mix= shiny, smooth
- Over-trituration= warm, wet, soft, sets too quickly
- Under-trituration= dry, dull, crumbly, sets too quickly
- Low-Copper- _____% Cu in the alloy
- High-Copper- ____% Cu in the alloy
- Low-Copper– <12% Cu in the alloy
- High-Copper– ≥12% Cu in the alloy
γ2 phase missing in high/ low copper alloy
High copper
less corrosion and creep is seen in high/low copper alloy
High copper
Which alloy particles is stronger and sets faster- Spherical/ admixed
Spherical
Better proximal contacts- Admixed/spherical
Admixed
Dental Amalgam contraindications
Very small Class VI lesions
High esthetic demands
Allergic to metals
- Preparation walls diverge occlusally due to
orientation of enamel rods in ________ class of amalgam
five
Acute mercury toxicity symptoms
– Muscle weakness (hypotonia)
– Loss of hair (alopecia)
– Weight loss/GI disorders
– Exhaustion
Mercury Forms
- Methylmercury= organic, most toxic
- Elemental= liquid metallic, in dental amalgam
- Mercury salts= inorganic
Enamel bonding has _______ MPa of shear bond strength
20+ MPa of shear bond strength
Reliable and predictable enamel/ dentin bonding
Enamel bonding
Enamel and dentin composition
organic
mineral and
water
Enamel
2% organic, 88% mineral, 10% water
Dentin
25% organic, 50% mineral 25% water
- Etched enamel
- Etched dentin
- Etched enamel - chalky or frosty white,
creates microporosities - Etched dentin - exposes layer of
collagen, widens dentinal tubules
Primer example and it causes
HEMA, Contact dermitities
Etching is done with _____ and time
Etch for 15 seconds
* 30-40% phosphoric acid
___________ Prevents collagen collapse
Primer
Bond/Adhesive creates ______bond
Micro-Mechanical bond
Hybrid Layer is a mechanical interface blw
Mechanical interface between tooth and adhesive
Larger fillers= less/more strength
Higher filler content= less/more water absorption
more strength
less water absorption
- Composites shrink as they polymerize ___%
2-3%
Higher C-factor means Less/more chance for shrinkage,
microleakage, and post-operative sensitivity
more
Glass Ionomer composition
- Acid= polyacrylic acid
- Base= fluoroaluminosilicate glass
Glass Ionomer rely on________________ bond
composite resin rely on _____________ bond
chemical
MMB
anhydrous single pastes that contain major ingredients of both
CR and GI except for water
Compomer
More rapid polymerization
slower polymerization
Resin-Modified Glass Ionomers
Compomers (Polyacid-Modified Resin
Composites)
attracted use in orthodontics
Compomers (Polyacid-Modified Resin
Composites)
- Self-Cure composites _____ paste system
- Light-Cure _______ Single-paste system
TWO
Single
_________ nm light needed to initiate polymerization in light cure resins
468 nm
Light-cure ___________ photoinitiator
– Camphorquinone is
photoinitiator
Self cure initiator and activator?
– Benzoyl peroxide is initiator
– Tertiary amine is activator
Enamel can be etched for up to __________ seconds and dentin can be etched for up to _________ seconds.
Enamel can be etched for up to 20-30 seconds and dentin can be etched for up to 15-20 seconds.
Which type of dentin require a longer etching time
tertiary dentinis the most irregular and resilient, so it requires a longer etching time
Composite shade 1 represents the_______chroma and_________value
1 represents theleastchroma andhighestvalue (whiter)
Darker and more opaque shades of composite take _________to cure.
Darker and more opaque shades of composite take longerto cure.
The patient has brown discoloration and chalky enamel, which is indicative of___________I.
amelogenesis imperfecta type III.
The order in which teeth most commonly experience cracked tooth syndrome is:
Mandibular second molars
Mandibular first molars
Maxillary premolars
Hot/cold sensitivity within two weeks of an amalgam dental restoration placement is most likely due to the _____________
thermal conductivityof the amalgam
Root cariesare often difficult to properly isolate and keep clean making it a great option for_____________.
resin-modified glass ionomers.
Layering resin composite over glass ionomer is commonly referred to as a ___________.
sandwich technique
Composite is an ideal restorative material for small Class __________ slot preparations when standard isolation isnotan issue.
Class II slot preparations.
Abfraction is presented with ________ cervical lesions. Abrasion is presented with __________ cervical lesions.
Abfraction is presented with angular cervical lesions. Abrasion is presented with rounded cervical lesions.
Nanofill particles have least/ most wear resistance.
Most because Composites with the smallest-sized spherical particles exhibit the mostwear resistance.
Senile caries, or root caries in older patients, results from ___________.
gingival recession.
___________ cementis the most commonly used cement for ceramic inlay and onlays.
Resin cement
_________ is an excellent choice of material to restore root caries as it has the ability to release fluoride.
Resin-modified glass ionomer
One of the disadvantages of glass ionomers is the _______ of the material, which can be irritating if placed close to the pulp.
Low pH
Abfraction has an _________ notch in thee cervical region, while abrasion has a __________ notch.
Angular and rounded respectively
Which of the following composite fillers exhibits the most wear resistance?
Nanofill
Occlusal caries will most often present with gray discoloration shown through the translucent enamel.
Translucency of the enamel
Why does dentin collapse during etching?
Exposed layer of collagen
which base or liner may interfere with the polymerization of a resin composite restoration?
ZOE
