OPERATIVE Flashcards
- What type of mercury is most harmful in the dental setting?
Methylmercury
3 facts about Hydroxyapetite (HA):
- Hexagonal
- White powder
- Low biabsorption rate
Naturally occurring HA in enamel and dentin
CHA Carbonate- substituted HA
CHA increases solubility of enamel
Protective mechanisms (4) of saliva are:
- Bacterial clearance (Glycoproteins in spit make bac clump together)
- Buffer (urea etc dilute plaque acids)
- Antimicrobactiral ( lysozyme, lactoferrin,lactoperoxidase)
- Remineralization (CA, Ph, K, F + proteins like proline-rich sIgA ect)
How does F+ work?
- Remineralizatin
- Dec Solubility of enamel ( lower critical pH)
- Slow metabolism of cariogenic bacteria
4.
____ is the primary causative agent of initial caries
Mutans StrePtOcoccuS ( gram POS bac)
Mutans carry postive charges
Critical pH of enamel, dentin, cementum?
Enamel ( FA) = 4.5
Enamel (CHA) = 5.5
Dentin/Cementum = 6.2-6.7
Enamel demineralization occurs at what pH?
5.5
Pit and fissure lesion shape
Inverted V
Smooth Surface lesion shape
V shaped
Infected dentin vs Affected dentin
infected = wet mushy soft affected = deeper dry leathery ( demin but no bac)
_____ necc for remineralization
intact surface
Progress of lesion is ( order of a cavity)
- ennamel demin
- dentin demin
- ## enamel caviation
The bacteria ___1__ secretes the enzxyme __2___ that causes the formation of extracellular polysaccharide, which allows it to stick to smooth tooth surfaces.
What else does this enzyme do? ___3____
What does this bact contain that makes it grow as opposed to other bac? ____4____
- Streptococ. Mutans or mutans streptococcus
- Glycosyltranferace
- It produces (Metabol. sucrose to lactic acid) and tolerates acid aka acidogenic/aciduric.
- BActeriocins - kill off competing org
Primary cause of dentin caries
lactobacillus
Primary cause of root caries
Actinomyces
Components of Saliva that make it protective
- Glycoproteins ( bacteria agglutination)
- Urea
- Lysozyme (destroy cell wall)
- Lactoferrin (bind to Fe- inactivates it from bac)
- Lactoperoxidase (inactiv. bac enzymes)
- sIgA (secretory immunoglobins antb against bac)
- CA, Ph, K, F
- Crystatin, Histatin, Statherin, proline-rich protiens
CLinical Exam methods for checking for caries
- Visual ( texture /color)
- Tactile ( explorer)
- Radiographs
- Transilluimnation
_____ is loss of tooth structure from mechanical wear
Abrasion (Pathologic Or tooth brush)
most common cause of abrasion = porcelin/ceramic crowns against teeth)
amalgalm marginal gap/ditching = ?
0.5mm or LESS ; no need to replace
____ is caused by acidic food or bev.
Erosion
no bac involved
Ultra Fine Finishing burs have ___ blades?
30 -40 blades
_____ is occlusal wear from fxnl contacts with opposing natural teeth.
Attrition (burxism)
Cutting Instrument number formula 1st Number = 2nd Number = 3rd Number = 4th Number =
- Blade width
- Cutting edge angle ( omitted if 90 deg)
- Blade Length
- Blade Angle
things i want an instrumetn ( penis)
Width [90 omited] Length Angle [curved penis]
The scalers are?
Graceys ( 1-2, 7-8, 11-12, 13-14)
Where are sickle scalers used
Supraging
Where are Currettes used?
Subgingiv
Slow speed drill operates at?
<12,000 RPMs
Lowest possible =400RPMs
Which bur is best for caries removal
Large Round Bur
High Speed drill operates at?
> 200,000 RPMs
Which bur is better for end cutting?
Carbide ( produces less heat)
Which bur is better for side cutting?
Diamons ( produces more heat and has inc hardness)
Cutting burs have ___ blades?
6 blades
______ is defined by the extent of the carious lesion
Outline form
Internal Walls of cavity prep are?
Pulpal
Axial
________ is the jxn of two walls?
Line angle
Dimensions of 330 bur?
1.5mm L x 0.8mm W
Outline for is descirbed by the external outline of the tooth surface to be included in the prep along the ________________.
Cavosurface margin
________ is the jxn of THREE walls?
POINT Angle
Finishing burs have ___ blades?
12 Blades
Eame’s Ratio?
50% Mercury
50% Metal Alloy
What are the components of the metal alloy in amalgam?
50% metall alloy Sliver [strength] Tin [corrosion] Copper [ Strength] Zinc [ Deoxidizer]
(Amal) kept his (silver) in a (tin) can with his (pennies) (copper) near the (sink) (Zinc)
Silver, Tin, Copper, and Zinc are metals in amalgalm what properties does each contribute to the alloy?
Silver = Strength Tin = Corrosion Copper = Strength Zinc = Deoxidizer - but excess expansion if moisture contaminates zinc
Sickos (Silver,Copper) are strong and
Tin-zin = blew away the rock with air ??
Adv (3) of Spherical Amalgalm
- Easier to condense
- Stronger
- Sets faster
speherical = mircospheres of various sizes
Adv of Admixed
- Better proximal contacts (
Disadv = Reqs more condense force
admixed = mix of irregular and spherical parts
With burs as ____1___ increases, ____2____ decreases.
Cutting efficeincy INC
Smoothness DEC
While creating the outline form of a prep do you follow the caries for depth?
No. Initial depth of 0.2-0.5mm into dentin
Only working on the width and length
When to use amalgalm?
Mod- Large lesions Isolation difficult (dry) Lesion onto root fondation/build up/abutment Heavy occlusal loading
____ is loss of tooth strx in cervical d/t tooth flexure
Abfraction
Fine Finishing burs have ___ blades?
18-24 blades
4 main reasons its more difficult to bond to dentin vs enamel
- Compostion [Denitn = 25% water- more org mat]
- Structure [Enamel rods are || dentin has callagen wich is like spageti]
- Depth [deeper = inc in fluid filled tubes ( near pulp) ]
- Smear Layer [dec dentin permeability]
GV Black's Cavity Classification Class I Class II Class III Class IV Class V Class VI
- Pits and fissures [post]
- Proximal [post]
- Proximal w/o incisal edge [Ant]
- Proximal WITH incisal Edge [Ant]
- Cervical third
- Only incisal edge of ant or cusp tip of post
Flat pulpal/ging floors, Round internal line angles, are part of which step in a cavity prep
Resistance Form
After etching you primer with what?
HEMA ( monomer + solvent )
infiltrates enamel prisms and dentin tubes; prevent collagen collapse
HEMA if contacts skin causes CONTACT DERM (
Dimensions of 245 bur?
3mm L x 0.8mm W
ETCH, PRIME, BOND….whats the bond?
Bis-GMA (bisphenol-a-glycidyl-methylmeacrlate)
Chem BONDS to underlying PRIMER AND overlying COMP thru MMA bonds
Outline form of prep gingival floor depth?
- 5mm of clearance
- you can see 0.5mm b/w ging floor of prep and adj tooth
Acid etch = ?
35% phosphoric acid
Acid etch for how long?
15 sec rinse
10 sec
Etched enamel»_space;
chalky white
creates mircoporosities
Amalgalm rxn stages:
y = unreacted tin sliver y1 = strong Ag-Hg matrix [highest strength/ corrosion resistance] y2 = weak Tin-Hg [weakest - creep/corrosion]
Deformation of amalgalm unders compressive stress = ?
creep
___________ = mechinical interface b/w tooth and adhesive
hybrid layer
micromechanical bond (
Under-titurated amalgalm looks like?
Dry, crumbly, sets too quikly
Etching dentin»_space;
exposes layer of collagen, widens dent tubes
Amalgam capsule has __
alloy powder and liquid Hg
External Walls of cavity prep are?
Buccal/Facial
Lingual
Distal
Gingival
Tituration ___
mixes amalgalm components- where the alloy particle is coated with Hg
The key to adhesive dentistry =
micromechanical bond
4th Gen bonding system contiains
Etch
prime
bond/adhesive
3 steps each in own contains ( ex opti bond)
5th Gen bonding sys contains
Etch
prime+adhesive (in one)
2 step ( ex: Universal optibond plue)
RMGI cement is used as a __
base
Vitrebond
If the extn of a prep is _______ the dist from the _______ to the _______, consider capping the tooth
more than 1/2
primary groove (to the)
cusp tip
Resistance form ***
** if from MOD to onlay your matin Resistance Form [RQ}***
CaOH is used as a
liner ( Dycal)
______ is to improve access and visibility
convenience form
Best bur for amalgam prep
carbide
what is GLUMA and how does it work?
5% gluteraldehyde ; 35% HEMA ( Hydroxyethyl methacrylate) water
occludes dentil tubules by cross-linking tubular proteins
Why acid etch ?
remove smear layer
6th GEN bonding syst
- Acid Ethc + Primer
- Adhesive
ex: Clear SE
* less post-op sensitivity
Self-etch bond systems disadv
- leave behind smear layer ( use carbide for less)
- Enamel bond not a strong
- Need to be refrigerated
- No rinse
ADV: less post- op sensitivty b/c smear layer
Class V prep walls for an amalgam should have ___ walls
Divergent ( d/t enamel rods needing to be supported)
7th gen bonding syst
all in one
ex L-pop
______ is the ratio of bond to unbond surfaces
C-factor
Class is INVERSELY proportional to C-factor
Class 1 = 5:1 (5) most shrinkage/microleakage/sens
Class 5 = 1:5 (0.2) least shrinkage
Best bur for composite
Diamond ( coarse)
It is called a ____ when a feather-edge margin is used in a gold onlay
Skirt
_____is beveled shoulder around capped cusp for bracing in a gold only
collar
Amalgalm prep resistance form
90 degree cavosurface margin
90 degree amalgalm margin
1.5-2mm depth thickness of amalgam
Amalgalm prep retention form
occlusal CONvergance
___ and _____ for resistance and rentention form when doing a gold onlay prep
Collar and skirt
Reasons why an amalgam marginal ridge would fx?
- Axiopulpal line angle not rounded
- Ridge too high
- occusal embrasure form incorrect
- Improper removal of matrix band
- Too much carving ( need 1.5-2mm depth)
Self-Cure Comp is _____1_____ with _____2___ as the initiator and ______3_____ as the activator.
- Two-paste syst
- Benzoyl Peroxide (Pimple)
- Tertiary Amine ( Activ)
Composite Resin components (3)
- Resin Matrix ( Bis- GMA can mimic effects of estrogen) negligible)
- Filler Particle ( Silica - Radiopauqe[barium] - affect properties)
- Coupling agent (Silane- promotes adhesion b/w resin & filler (tooth)- binds the inorg/org mat. with hydrogen and covalent bonds)
______ the c-factor means more chance for shrinkage, microleakage, and post-op sensitvity
HIGHER
What are the 3 forms of Hg?
- Methylmercury = most toxic
- Elemental = liquid metallic, in dental amalgalm
- Mercury Salts = inorganic
Glass Ionomer components
Acid = Polyacrylic acid Base = FLuoroalumnisilicate glass
Glass Ionomer ADV: (3)
- FLouride Release
- Self -adhesion to tooth
- rely on chemical bond (vs micromech in comp)
DISADV: Weaker ; longer setting with less setting contrl
______ is the prevention of displacement of restorative material
Retention form
???
GI ( Salt-matrix) >
RMGI »_space;
Compomer aka Polyaicd modified comp resin»_space;>
Resin Composite ( resin -matrix)
S/s of Mercury Tox
- Hypotonia ( muscle weakness)
- Alopecia ( loss of hair)
- Weight loss/ GI disturbance
- Exhaustion
Most toxic form of mercury?
Methylmercury
RMGI sets by :
Both acid base ( GI ) AND Free- radical addition polymerization ( comp) PLUS fluoride release ; stronger than GI
_____________ is the prevention of tooth or restoration fx from occlusal forces
Resisitance form
Light-Cure Comp is _____1_____ with _____2___ as the photoinitiator .
- Single Paste syst
- CamPHOrquinone is PHOtointiactor
- when you CAMP you take PHOTOs*
- Blue visable light @ 468nm light needed to polymerize
Convergent walls, dovetail, and micro-mechanical bonding are aspect of ______ in regards to a cavity prep?
Retention Form
Macrofill / conventional composite has
80% filler ;
Particle size is 8 microns ( makes it strong)
- rough and wear inc roughness over time
Microfill composite has
40% filler ;
0.04 microns ( weak) Particle size
- but better polish / wear resistance ; inc flexure (good for brusixm)
- class V
Microfill composites are considered an appropriate choice for restoring class V cervical lesions or defects in which cervical flexure can be significant. This is true for cases of bruxism, clenching, and stressful occlusion. Their low modulus of elasticity allows them to flex during tooth flexure, better protecting the bonding interface.
Microfill composites also provide a smooth and polished surface in the finished restoration that is less receptive to plaque.
Hybridofill composite has
80% filler ;
1 micron particle size
Both strong good wear -
Nanoofill composite has
0.005-0.01 microns partic size
When comparing composite types the ___1_____ have more strength while the ______2________ have lower water absorption
- larger fillers have more strength ( dnt polish or wear well)
- High filler % ( less room for water to seep in)
Compomers ( polyacrylic modified resin comp) is an:
Annhydrous paste that contains major components of both comp resin and GI ( excpet for H2O) ; slower polymerizationn plus F+ release
- ORTHO*
______ refers to the lightness or darkness of a certain area or color.
Value ( black - gray - white)
Measured on the vertical axis of a Munsell color schematic
T/F. Amalgam does NOT bond directly to the tooth structure.
TRUE.
Mechanical features, such as convergence of cavity walls, adequate preparation depth, grooves, and slots, are incorporated in cavity preparations to retain amalgam fillings.
RDT (remaining dent thick) of greater than 1.5 mm you would place __?
GI cement can be used as cavity liner
________ refers to the angle of lighting or type of light source that make colors appear as the same or different.
Metamerism
The distance traveled by light into tooth structure before it is reflected back outward is known as its _____-
Degree of translucency
The composite-resin restorative material is ___1___ bonded to the adhesive resin through polymerization through ____2_____ bonds
- chemically
2. methyl methacrylate (MMA)
The use of cavity liners should be limited to
those areas of the preparation where there is a possibility of a minute pulpal exposure.
______ teeth are most commonly affected in baby-bottle caries because of bottle positioning.
Maxillary anterior
Compared to RMGICs, resin composites are:
Stronger
More color stable
More wear-resistant
RMGI leak F+
A pH of ____1___ is called the ____2____ because any further drop in pH results in the demineralization of ___3___.
- 5.5
- “critical pH”
- enamel
________ is the degree of the ability of light to pass through.
Penetrance
Bacterial plaque is made up of ______
organic components and non-organic components (minerals).
Organic components of Bacterial plaque include (4):
Polysaccharides
Glycoproteins
Proteins
Lipids
Where should you place a cavity liner ?
- Areas where carious tissue is left in the prep
- Areas of prep where there is a possibility of a minute pulpal exposure
* Application of cavity liners along the entire wall will reduce the retention or bonding of restorative material.
Value
Value refers to the lightness or darkness of a certain area or color.
Non-organic components of bacterial plaque are?
are the mineral components that include the following:
Ca2+
Na+
K+
P-3
F-
Esthetics Facts:
Rounding the incisal point angles of maxillary incisors removes the sharp angles that make the teeth appear worn down and abraded.
Shortening and flattening of incisal edges makes a person appear older, because it also insinuates abrasion of teeth due to old age.
_____ refers to the color itself and its distinctive shades.
Hue ( red yellow blue)
measured by degrees in a circle and is considered the actual color - wavelength of visible light
criterion when determining the effectiveness of a visible light-curing unit are:
- Shade of the composite [affects penetration of light ]
- Wavelength [470 nm.]
- Light exposure time [ not short, not long]
* * NOT F+ release capacity*
Strong ___1____ forces and large condensers should be used to properly condense which type of amalgam alloy 2?
- lateral
- spherical
Spherical vs Admixed amalgam
Spherical= high compressive strength req. strong lateral condensation forces to ensure proper adaptation to the cavity preparation.
Has large particle composition, necessitating good condensation to minimize the gap between the cavity prep and the amalgam.
The snowplow technique employs
the use of flowable composites in conjunction with the posterior composite restorations.
_____________ is where the low viscosity resins micro-mechanically interlock with dentinal collagen.
The hybrid layer, or hybrid zone,
RDT ( remain dent thick) of 0.5 mm or less you would place __?
CaOH as a liner then GI on top
choice of cavity-lining material depends upon
the remaining dentin thickness.
remaining dentin thickness is greater than 1.5 mm, glass ionomer cement can be used as cavity liner but for a remaining thickness of 0.5 mm or less, calcium hydroxide should be used, then glass ionomer should be placed.
The four main characteristics or determinants of proximal grooves are
position, translation, occlusogingival orientation, and depth.
Depth refers to the extent of translation, such as the direction of the movement of axis of the bur.
Removal of smear layer has these 4 consequences:
- Increases wetness of dentin
- Increases bond strength
- Makes microleakage more significant because barrier of bacteria to pulp is removed
- Increases fluid flow onto the exposed dentin surface
cavity liners protects the endangered pulp from
thermal, chemical, electrical, and mechanical trauma.
Dentin provides _____(3)______ to above-lying dental enamel.
chroma, opaqueness, and fluorescence
_______ removes the smear layer and hydroxyapatite within the intertubular dentin, in addition to exposing the collagen fibers.
Etching
Acid-etching is thought to remove the smear layer and creates a microporous enamel layer on which resin tags are formed by adhesive resins.
carving of amalgam should include
- ridge should be carved very nearly to the height of the adjacent marginal ridge.
- Sharp instruments
- Carving strokes should always start on tooth and proceed to amalg-enamel jxn
Bleaching agents like hydrogen peroxide and carbamide peroxide act on
both the dentin and enamel.
Bond strength relies upon the formation of _____ in enamel.
resin tags
Rampant caries control protocols suggest
that caries should be removed, and glass ionomer cement restorations should be placed until the true pulp status can be assessed.
Fluoride is incorporated into enamel during the __________ stage of tooth development.
calcification/mineralization
Fluoride ions can replace the hydroxyl ions during the calcification stage of tooth development, which results in a structure that is more compact and resistant to caries.
___________ is the primary means of retention for pit and fissure sealants.
Micro-mechanical retention
Continuous exposure to visible light used for curing the composite can cause serious damage to the
Retina
Prolonged visible light exposure can lead to photoreceptor cell damage.
When the remaining dentin thickness _____1_____, glass ionomer cement can be used as cavity liner but for a remaining thickness of ____2______, calcium hydroxide should be used, then glass ionomer should be placed.
- is greater than 1.5 mm
2. 0.5 mm or less
bacterial species is considered an early colonizer of supragingival plaque?
Streptococcus sanguinis
The formation of dental plaque consists of three distinct stages:
- Formation of pellicle on the tooth surface
- Initial colonization by bacteria
- Secondary colonization with plaque maturation
Within a few seconds after cleaning the teeth, a thin layer called pellicle is formed on the tooth surface by the saliva, which is then colonized by bacteria within a few hours.
The initial colonizing bacteria are collectively known as supragingival plaque and predominantly consists of Gram-positive facultative microorganisms (Actinomyces viscosus, Streptococcus sanguinis).
It is very important to consider ________ when restoring damaged incisal edges of maxillary incisors.
morphology and translucency
________ is the intensity of any particular hue or color.
Chroma (saturation)
The chroma is measured radially outward from the neutral vertical axis [value] and is considered the purity of the color ( light blue to Bright blue); horizontal
_________ is the emission of light by a substance that has absorbed light or other electromagnetic radiation.
Fluorescence
The caries process occurs when
bacterial acid demineralization exceeds the remineralization by salivary components.
Retention features for class V alloy restorations are typically placed on
Incisal/occlusal and gingival walls
The thickness of enamel in the _____1____ surface is greater than that of the _____2____ surface.
- incisal
2. facial
The rubber dam should be punched_____ to the designated tooth for class V restorations
1 mm facial
enables the rubber dam to completely cover the area to be isolated and making subgingival placement easier if needed
The first increment in a class II restoration must be ____ thick if the snowplow technique is not used. The first increment is placed on the gingival floor of the restoration.
1-mm
________ describes the absorption and scattering of radiation in a medium.
Opaqueness
The maximum depth of resin that can be properly cured per layer is approximately ________.
2 mm
If the composite thickness exceeds 2 mm, inadequate curing occurs. This phenomenon is especially seen with darker shade composites. Filler particles and coloring agents tend to scatter or absorb the curing light within 1–2 mm of the material.
( the first layer in slopt prep = 1mm)
The initial colonizing bacteria are collectively known as supragingival plaque and predominantly consists of _________.
Gram-positive facultative microorganisms (Actinomyces viscosus, Streptococcus sanguinis).
Primer use is intended to provide two main functions in dentin bonding:
- Infiltrate and remove water from enamel prisms, dentin tubules, and exposed collagen network
- Form hybrid layer because it is made of solvents and bi-functional/amphiphilic penetrating monomers
DISADV of microfilled composites include the following:
4
- Increased thermal expansion
- Decreased tensile strength ( small partc size)
- Increased water absorption ( less filler)
- Increased polymerization shrinkage (
40% filler ; 0.04 microns ( weak) Particle size
- but better polish / wear resistance ; inc flexure (good for brusixm)
________ penetrate the collagen network and allow the adhesive resins to form microtags within the intertubular dentin.
Primers
Indications of composite restorations are:
Small- and moderate-sized restorations
Conservative tooth preparations
Areas where esthetics is important
___1__ phase is the major matrix phase in set amalgam, has good __2____ and ___3____ resistance.
1 . γ-1
- strength
- corrosion
how deep retention grooves must be to resist explorer-tip displacement?
0.5mm
Retention grooves are the secondary retention features of a preparation. They are positioned 0.2 mm inside the DEJ, maintaining the enamel support. They are recommended in tooth preparations with extensive proximal boxes in order to enhance retention form and counter proximal displacement. They must be deep enough to resist explorer-tip displacement. Ideally, grooves are 0.5 mm deep.
indications for the placement of a base
- Prevention of other dental materials from irritating the pulp
- Replacement of missing tooth structure
- Thermal protection for the pulp
Bases replace missing tooth structure and support the final restoration.
- insulate the pulp from drastic temperature changes experienced by the restoration.
- provide structure to condense against when placing amalgam.
- protect the pulp from agents that may irritate it.
_________ is the material’s ability to resist deformation under load.
Flexural strength
T/F/ The illusion of decreased width can be achieved with horizontal highlights.
FALSE. increased width can be achieved with horizontal highlights.
Which composite resin constituent provides the most radiopacity?
Barium ( filler)
_______ teeth creates microporosities that adhesives can infiltrate to create retention for composite-resin bonding.
Acid etching
Define Hardness.
Hardness is a measure of how resistant solid matter is to various kinds of permanent shape change when a force is applied.
T/F. Conventional glass ionomers contain water soluble polymerizable resin
FALSE.
Conventional glass ionomers contain water soluble polyacids and basic ion-leachable glass in their composition.
RMGI’s were formulated by adding a water soluble polymerizable resin such as 2-HEMA in the acidic cement liquid.
_______ corrodes the carbon steel and anneals the cutting edge of the bur.
Heat sterilization
advantageous properties of zinc oxide-eugenol cement?
- It provides an excellent marginal seal.
- It has a soothing effect on dental pulp.
- It can be easily removed from cavity preparations.
_______ is the tendency of solid materials to return to their original shape after being deformed.
Elasticity
disadvantages of amalgam restorations (3)
Does not bond to tooth structure on its own
Esthetics
Brittleness
Composite resins are classified as ___(3)______ based on their viscosities.
flowable, condensable, and packable,
- flowable = low viscosity (20-25% lower then normal resin)
- flowable d/t inc resin)
- Inc Filler % INC viscosity
_______ is the infolding of the outer surface of the tooth and must be diagnosed radiographically.
Dens in dente aka Dens invaginatus.
It occurs most often in maxillary lateral incisors, and bilateral occurrence is not uncommon.
______ of the resin composites measures the material’s ability to resist the propagation of a crack.
Fracture toughness
Fracture toughness is a quantitative way of expressing a material’s resistance to brittle fracture when a crack is present.
Brittle fracture is very characteristic of materials with low fracture toughness.
Placement of ______ ________into the cavity prep often allows the amalgam to set before it is adapted and properly condensed into the floor and walls of the cavity, resulting in voids in the restoration and an open gingival margin.
excessive amalgam
T/F. The illusion of increased length can be achieved with vertical highlights.
True.
T/F. Surfaces smoother than usual give the impression of a larger size.
TRUE.
Whenever restorations are finished with unusually smooth surfaces, they give the impression of larger size and vice versa. Teeth appear larger than their actual size when the value is increased.
T/F. Conventional glass ionomers use free radical polymerization to cure
FALSE.
Conventional glass ionomer cements undergo a chemical self-setting acid-base reaction created by mixing an ion-leachable fluoroaluminosilicate glass powder with an aqueous polyacrylic or polcarboxylic acid.
The radiant exposure for a curing light producing 1,000 mW of power with a spot size of 2 cm² and an exposure time of 40 seconds is
20,000 mJ/cm².
(1,000 mW × 40 s) ÷ 2 cm² = 20,000 mJ/cm²
_______ roughens the exposed enamel rods and dentin, thus creating micromechanical abrasions that allow the bonding agent to flow and adhere to the tooth surface.
Acid etching
_____ removes surface debris, allowing for a clean bonding site.
Acid Etching
T/F. Conventional glass ionomers contain basic ion-leachable glass
TRUE
________(2)______ deposition can result from aging or mild irritation such as abrasion, attrition, and occlusal stress.
Sclerotic dentin
Sclerotic dentin is harder, denser, less sensitive, and more protective of the dental pulp.
The setting reaction of self-cure, chemical cure, or auto-curing sealants is __________ in nature.
exothermic
A significant amount of heat energy is liberated. It is advised to use light-curing sealants for safety, good manipulation, and ease of handling.
_______ creates higher bond strength between composite restoration and tooth structure while also decreasing micro leakage.
Acid etching
Amalgam alloy typyes ( 2)
Low-CU (<12% ; Y, Y1, Y2) and High CU (>12%+ ; Y,Y1 - less corrosion and creep)
If a low-copper, zinc-containing alloy is moisture-contaminated, it will result in surface blistering, internal corrosion, and a delayed expansion of up to 4% by volume beginning 3 to 5 days after the contamination and continuing for up to 6 months, which can lead to creep and a reduction in strength of up to 24%.
Addition of zinc to an amalgam reduces the negative effects of delayed expansion.
trituration does what?
removes the oxide coating and wets each particle of alloy with mercury. Properly triturated amalgam is a homogenous mass with a slightly reflective surface. It flattens slightly if dropped on a tabletop.
Enamel cavosurface angles of _____ are ideal.
90–100°
Such angles conserve dentinal support and restoration strength, helping the restoration withstand the forces of mastication without fracture.
Retentive bevels are typically found around the margins of a ______ restoration.
class V
______ ______ ( 2) is a condition in which a combination of small white, brown, and yellow spots are seen all over the surfaces of the teeth.
Mottled enamel
tx: Microabrasion with hydrochloric acid (HCl)/pumice
_________ is the term for the enamel bevel placed on the facial side of a class IV preparation
Esthetic bevel
Esthetic bevels are typically placed at 60°.This bevel is placed to remove or mask the line of demarcation between the restorative material and the tooth structure
Placement of an esthetic bevel also makes the restoration conservative, increases the resin bond strength, and decreases the chances of fracture.
DMFS” stands for which of the following?
Caries prevalence can be recorded as “DMFT” or “DMFS” as follows: Decayed Missing Filled Surfaces Teeth
Most important in shade selection
Value
Which (chroma, value, hue) depends on wavelength
Hue
“Hue rides the wave”
Indirect restoration vs direct resotration
indirect = anything made by lab ( inlay,onlay, crown ect)
direct = comp amalgam
Three parts of the hand instrument
Blade, Shank, Handle
The ____1_____ method was developed called _____2____. It is caries ___3__ by the application of a gel to the tooth which selectively softens the carious dentin, thus facilitating removal of this tissue. This minimizes pain and should not affect healthy tissue.
- chemomechanical
- Carisolv (Medi Team)
- removal
Enamel comprised of __1__ with a __2___ surface energy while dentin is comprised of _3__ with a _4__ surface energy.
- Hydroxapetite
- High surface E
- Hydroaptetit AND COLLAGEN
- Low surface E
A triangular reamer with 60 degree cutting edges would require ______ degrees of rotation for one reaming motion arc.
The motion of reaming involves rotating an instrument clockwise, in an arc that goes from one cutting edge to the next. A triangular reamer having three 60 degree cutting edges would, therefore, require 120 degrees of rotation in order for one arc.
low-copper amalgam alloys:
Low-copper amalgams form a tin-mercury (γ2) phase, which is highly susceptible to corrosion. Because of this, high-copper alloys have been developed and are now the primary amalgam type in use. Low-copper amalgams used to be more prominent in the first half of the 20th century.
Resin-modified glass ionomer (RMGI) has greater ___________ than glass ionomer (GI)
flexural strength
_____ are undifferentiated mesenchymal cells that form the dental pulp.
Fibroblasts
_______ form the primary, secondary, and tertiary layers of dentin.
Odontoblasts
_____- form the highly calcified dental enamel.
Ameloblasts
______ is a protein that forms the organic matrix of mature tooth enamel.
Enamelin
Injury resulting in tissue changes from excessive occlusal forces applied to a tooth or teeth that have normal, health supporting periodontium = ______?
Primary occlusal trauma
Secondary occlusal trauma is an injury resulting in tissue changes from normal or excessive occlusal forces that are applied to ___________.
a tooth or teeth with reduced support
The main characteristics of this type of trauma are the presence of bone loss, attachment loss, and normal OR excessive occlusal forces.
Two types of dental amalgam
Admized and Spherical
Admixed (mix of irreg/sphere, more condensation force, Better prox contact)
Speherical ( microsphere, easy to condense, Stronger, sets faster)
In dental amalgam what does the alloys contribute? Sliver= Tin= Copper Zinc =
Silver = strength Tin = corrosion Copper = strength Zinc = deoxidizer [of other alloys] but excess expansion if moisture contaminated
In the four observed zones of a sectioned incipient lesion, the deepest zone is?
Translucent
- Dark zone- the light is blocked by the many small pores, which are too small to absorb quinoline solution. These smaller vapor-filled pores make the region appear opaque.
- Body of the lesion- the largest portion of the incipient lesion during the demineralizing phase.
- Translucent zone- the deepest and advancing zone of the enamel lesion.
- Suface zone- the area unaffected by the caries process. It has a lower pore size than the body of the lesion and radiopacity when compared to unaffected enamel.
T/F. GI chemically bonds to not only enamel and dentin but also cementum.
TRUE.
This is particularly helpful for subgingival restorations
Benefits of using amalgam with smaller particle size?
- Smoother surface
- Increased working time - sets slower
- Stronger restoration
CONS:
- Rougher surface
- larger particle size = weaker
GI is in fact made from the reaction of _____1_____ with ___2____.
- silicate glass
2. polyacrylic acid
Whats wrong with the amalgam if it is shiny and smooth
Nothing - normal
Amalgam phases
Y =
Y1=
Y2 =
Y = unreacted silver-tin Y1 = strong silver-mercury matrix *HIGHEST STRENGTH* Y2 = weak tin-mercury * corrosing/creep/weakest*
Y1 = corrosion resistance
_____is an aqueous or volatile organic suspension of zinc oxide or calcium hydroxide (Dycal) that can be used on the cavity surface.
A cavity liner
Whats wrong with the amalgam if it is warm, wet, soft, sets too quickly
OVER-titiurated
is a material which occludes the dentinal tubules and provides a protective barrier for the freshly cut tooth structure of the prepared cavity.
Sealer (cavity sealer)
Base (cavity base)
________, usually cement, is used to protect a prepared cavity before the insertion of a permanent restoration. It is used to protect the pulp tissue and replace any dentin removed.
The ART technique is the ____1______, which only uses ________ to excavate carious lesions.
- Atraumatic Restorative Treatment
2. hand instruments
T/F. Older Amalgalm alloys had low amounts of copper <12%.
TRUE.
THis type has Y, Y1, Y2
Newer = ~20% Copper = Y, Y1 = less corrosion/creep
