Fichas
Operative test 1
Fichas del conjunto (200)
- 1treatment of disease and defects of hard tissues of teeth that doesn't require full coverage restorationoperative dentistry
- 2what does operative restore?form, function, and esthetics
- 3Where is enamel thickest and thinnest?Thickest at occlusal
Thinnest at CEJ - 490-92% hydroxyapatite strong and brittleenamel
- 5How are enamel rods arranged?Larger diameter near surface, smaller near dentin
perpendicular to long axis-->DO NOT LEAVE UNSUPPORTED - 6hypomineralized regions that extend into enamel from DEJenamel tufts
- 7thin faults between enamel rod groups that extend from enamel toward DEJenamel lamellae
- 8odontoblastic processes crossed into enamelenamel spindles
- 9Is DEJ hypo or hypermineralized?hypo zone
- 10What are factors of enamel solubility?More soluble as you approach DEJ
Fluoride lowers acid solubility - 11largest portion of tooth forms walls of pulp chamber and formed immediatly prior to enamel forms t/o life of pulp in root and coronal regionsdentin
- 12Canals extending from DEJ/DCJ to pulp lined with peritubular dentin and surrounded by interbuluar dentindentinal tubules
- 13describe dentinal tubules at pulpgreatest diameter and highest concetration
- 14secondary odontoblasts that respond to moderate irritantsreparative dentin
- 15primary dentin in which the peritubular dentin widens and fills witch calcified material less sensitivesclerotic dentin
- 16What's the hardness of dentin?1/5 enamel
3x harder near DEJ than pulp
50% hydroxyapatite - 17what gives rise to dentinal sensitivity?fluid movement in tubules
- 18idea that odontoblast processes are wrapped in nerves and dentinal tubules contain fluid when enamel/cementum is lost, seal is lost and pain results from fluid movementhydrodynamic theory of pain sensitivity
- 19gunk created when dentin is cut that prevents sensitivity but is hard to bond tosmear layer
- 20compare colors of enamel and dentinenamel: gray, semi-translucent, shiny and dependent on underlying dentin
white when dehydrated
dentin: yellow-white, dull opaque - 21softer than dentin and formed continually 50% hydroxyapatite, 50% organic material and watercementum
- 22what are the objectives of tooth preparation?remove defects
provide necessary protection to pulp
extend restoration as conservatively as possible
resist fracture when chewing
restore esthetics and function - 23what are prep walls designed to do?retain restoration
resist fracture - 24where are primary caries found?pits and fissures
enamel smooth surface
root surface - 25carries left by operator intentionally or on accident only acceptable when affected dentin near pulpresidual caries
- 26microleakage present at junction between restoration and tooth may not be visible on radiographrecurrent caries
- 27appearance of acute vs chronic cariesacute: light color
chronic: dark and shiny - 28Preparations: simple compound complexsimple = one surface
compound = 2 surfaces
complex = 3+ surfaces - 29internal wall of prep parallel to long axis of toothaxial wall
- 30internal wall perpendicular to long axis of tooth and above the axial wallpupal wall or floor
- 31wall perpendicular to long axis of tooth and close to gingival linegingival wall
- 32prepared cut wall that is flat and perpendicular to occlusal floor provide stabilizing seats for restoration and distribute stress in toothfloor
- 33where do we want occlusal forces directed?along the long axis of the tooth
- 34junction of prepared cavity wall and external surface of tooth bevel, 90, or champfercavosurface angle or margin
- 35when enamel rods are not supported by sound dentin brittle and fracture easilyunsupported enamel
- 36preparation on occlusal surfaceClass I
- 37prep on proximal surfaces of molars and premolarsclass II
- 38prep of proximal surfaces of incisors and canines that do not involve incisal edgeclass III
- 39prox surfaces of incisors and canines +incisal edgeclass IV
- 40prep in gingival 1/3 of smooth surfacesClass V
- 41prep of incisal edge or cuspclass VI
- 42depth of outline form for class Imax 2.0 mm for pit and fissure
- 43depth of outline form for class IIaxial wall depth .2-.8 mm into dentin
extend gingival margins apical to contact
extend interproximal margins to embrassures - 44enameloplastyremove shallow enamel fissure or pit (less than 1/3 enamel)
creates smooth surface - 45when is resistance (to fracture) form compromised?When margin exceeds 2/3 distance between central groove and cusp tip (must cap weak cusps)
when margin ends 1/2 distance between central groove and cusp tip (consider capping weak cusp) - 46what is involved in resistance form?internal line angles slightly rounded
external line angles slightly rounded
flat floors
bevels - 47sufficient thickness of restorative material for resistance?amalgam 1.5 mm
gold 1-2 mm
porcelain 2.0mm - 48what is involved in retention form?dovetail
wall length
convergence for amalgam/parallel for inlays - 49form that allows you to access the defect with good ergonomicsconvience form
- 50what is involved in secondary retention?retention grooves and points
- 51what is involved in secondary resistance?fewer extensions, round axiopulpal line angle
- 52alloy of silver, copper, tin and zinc mixed with mercury that can be packed into a dental preparation which will set up to form a solid restorationamalgam
- 53properties of amalgam (5)1. high compressive strength and low tensile strength (brittle in small bulk)
2. sensitive to moisture--expands
3. still a good choice in moisture situations since you can scrape out top contaminated layer
4. corrodes, although modern alloys have hi copper content to minimize
5. regenerates a seal with tooth via oxides--prevents microleakage - 54disadvantages of amalgam (6)1. poor esthetics
2. requires mercury hygiene
3. full depth prep needed
4. doesn't bond to tooth structure
5. thermal conductor, requires liner
6. may ditch at margins - 55advantages of amalgam (6)1. Less difficult to use in moisture control problems
2. Hi wear resistance and compressive strength
3. low cost, less time
4. long-lasting
5. regenerates seal
6. less prone to decay than composite - 56Indications for amalgam (8)1. Moderate to large class I or II
2. Heavy occlusal wear
3. High caries
4. difficult isolation
5. gingival margin on root
6. Class V in non-esthetic zone
7. Temporary restorations on questionable teeth
8. buildups under crowns for badly damaged teeth - 57what does isolation provide?visibility, access, and moisture control
- 58methods of isolationrubber dam
cotton rolls
retraction cord
isolite/isovac system - 59margins in amalgam prepall cavosurface angles on axial surfaces should be 90
margins can be slightly obtuse on occlusal surface
NEVER ACUTE--No undermined enamel - 60how deep should amalgam preps be?all the way thru enamel and .2 to .5 mm into dentin
- 61what is rule for outline form on amalgam prep?prep must not terminate in the bottom of a fissured groove or pit
- 62how do we achieve retention form in amalgam preps?don't bond to tooth structure-->converging walls or retention grooves
- 63how do we achieve resistance form in amalgam prep? (6)1. maintaining tooth structure to avoid tooth fracture
2. having floors perpendicular to occlusal force in multi surface restoration to prevent restoration fraction
3. Rounding internal angles to prevent tooth fracture
4. Smoothing outline form to prevent restoration fracture
5. Proper depth prevents restoration fracture
6. Avoid sharp external line angles in areas of occlusal stress to prevent restoration fracture - 64what do we classify a buccal pit amalgam and why?Class I
occurs in occlusal 2/3 of molar tooth
restores a developmental pit - 65axial depth of a buccal pit1.5 mm
- 66wall convergence of buccal pit?all walls converge except occlusal apex of triangle
- 67what bur for buccal pit?330
- 68convergence of class Iisthmus walls: converged 3*
walls at termination of buccal and lingual groove: diverged 3*
mesial or distal wall: diverged 3*--> leaves dentin support for ridge - 69minimum isthmus width for class I1 mm
- 70what depth do we need to achieve for occlusal amalgams inside DEJ?.2mm inside DEJ
molars: 2 mm
premolars: 1.5-2 mm - 71bur placement to enter long axis of toothbur inclines more mesially in mandible and distally in maxilla the further posterior we go due to curve of spee (AP)
bur inclines more lingually in mandible and buccally in maxilla the more posterior we go due to curve of wilson - 72shape of axial wall in class Vconvex
- 73what is found and occlusal axial LA and gingival axial LA in class Vretention grooves!
- 74convergence of class Vall walls diverge-->retention grooves needed
- 75what determines outline of class V?the extent of the carries
- 76depth of class Vtypically 1.5
minimum thickness of enamel left at gingival margin: 1 mm depth
margin is on root: .75 depth - 77where do you place retention grooves?entirely in dentin, just inside the DEJ!!!
- 78types of hand instrumentscutting (excavators, chisels)
non-cutting (amalgam condensors, mirrors, explorers, probes) - 79—green = face
red = nib
orange = cutting edge
pink = blade - 80pros of double ended vs single ended instrumentsdouble ended: more efficient
single ended: safer - 81types of shank anglesmon angle
contra-angles:
triple angle
bin angle - 82types of bevelsbi-bevels: chisels, hatchets
single bevels: gingival margin trimmers - 83types of gingival margin trimmersmesial: place bevels on mesial cervical margin of prep
distal: place bevel on distal cervical margin - 84instrument formula 4 numbers1. width of blade in .10 mm
2. angle of cutting edge to instrument shaft clockwise as percent of 360 (sometimes missing)
3. length of blade in mm
4. angle of blade relative to long axis of handle in clockwise centigrade as percent - 85ordinary hatchetsplace retention, sharpen line angles
- 86hoesplane walls, form line angles
- 87angle formerscreate retention
- 88straight/ wedelstaedt chiselplane walls
- 89enamel hatchetscut enamel
- 90gingival margin trimmerbevel
- 91types of burs (rotary cutting instrument)finishing burs
lab burs
surgical removal of bone
tooth prep - 92types of bur shanklatch-type
friction grip - 93types of bur shapesround
inverted cone
pear
straight fissured
tapered fissue - 94bur classification systemarbitrary numerical code in us for head size and shape
- 95carbide bursstiffere and stronger than steel but more brittle
- 96types of diamond bursflat end taper
flat end cylinder
flame
wheel - 97diamond bursdifferent particle size of diamond for diff purposes
higher hardness and cutting effectiveness
for intracoronal and extracoronal tooth prep
bevel enamel margins
enameloplasty - 98modified pen graspgreatest sense of touch!!
3rd and 4th fingers on nearby tooth, palm away from operator - 99inverted pen graspfor maxillary arch on anterior teeth
palm toward operator - 100palm-and thumb grasppower grasp
thumb rests on point distal from operating site - 101modified palm-and-thumb graspthumb on same tooth or adjacent tooth
power + delicacy - 102Sharpen instruments at first sign of dullness!! What do dull instruments do?more pressure
more pain
less control
takes longer
reduces quality - 103ways to sharpen instrumentstationary stones
mechanical sharpeners
handpiece sharpening stones - 104Basic principles for sharpening1. clean and sterilize instrument
2. position blade
3. use light pressure
4. use rest or guide
5. remove as little metal as possible
6. lightly hone unbeveled side
7. resterilize - 105process by which all forms of microbial life (bact, spores, fungi, viruses) are completely destroyedsterilization
- 106what are 4 acceptable methods of sterilization?autoclave
dry heat
chemiclave
ethylene oxide - 107heat and time for autoclaving250*F
15 PSI
20 mins - 108heat and time for dry heat320*F
60-120 mins - 109heat and time for chemiclave270*F
20-40 PSI
20 min - 110heat and time for ethelene oxideseveral hours, below 100*C
- 111an infectious microbiologic disease of teeth resulting in localized dissolution and destruction of calcified tissuesdental carries
- 112elements of caries formationteeth
bacteria (s. mutans)
substrate (carbohydrate) - 113most prevalent locations for caries?pit and fissures
- 114where do we find pits and fissure cariesclass I
occlusal surfaces posterior teeth
buccal pit on post molars
lingual surface of lateral incisors - 115how to ID pits and fissures cariesdrage explorer (not stick)
shadowing
radiographs when large enough - 116how fast do pits and fissure caries formpresence of hi conc of s mutans is followed by carious lesion in 6-24 mo.
place sealants shortly after eruption - 117how to diagnose interproximalradiographs (bitewings)
difficult to diagnose visually - 118characteristics of smooth surface class V cariesseen in gingival thinrd of buccal/lingual surface
indicative of high caries rate
reversible until cavitated and easily restored
prevalent in soda sippers - 119characterictics of root surface cariesrapid succcesion
asymptomatic
closer to pulp
difficult to restore
old ppl - 120caries developed at margin of restoratioreccurent/secondary caries
- 121gelationous mass of bacteria adhering to tooth surfacedental plaque
- 122types of bacterias. sanguis
s. mitis (normal oral flora, slows growth of s mutans)
B. melaningenicus (obligate anaerobe assoc with PD) - 123what pH does demineralization of enamel and dentin occur?enamel: 5.5
dentin: 6.2 - 124what happens to ph after sugar exposure?pH remains below 5.5 for 20-60 min after each sugar exposure
- 125reversible until cavitation takes placedemineralization
- 126process that occurs in enamel when there is no cavitation and ph is above 5.5 can occur with HA crystals or Fl- HA crystals being taken from saliva for cystal formation an ongoing process in every oral cavity as ph shiftsremineralization
- 127benefits of salivapH buffer (bicarobonate)
bacterial clearance (1-1.5L flushes non-adherent bacteria and excess food debris)
direct anticariogenic activity (lysozymes, lactoperoxidase, lactoferrin) - 128methods of caries preventiongeneral health
xerostomia
fluoride
oral hygiene instructions
dietary counseling
sealants - 129steps to placing occlusal amalgam1. Place liner/base for deep caries
2. Seal dentinal tubules (only in very young or sensitive teeth)
3. Mix amalgam
4.dispense into well and pick up with carrier
5. deposit amalgam into prep
6. condense amalgam with hollenback condensor
7. overfill prep 1 mm beyond margins
8. pre-carve burnishing
9. carve amalgam to margins
10. check and refine occlusion with articulating paper
11. smooth surfaces - 130what is an example of a liner and how do we place it?Ca Hydroxide (Dycal, life)
2 paste system, mixed and placed in deep areas away from margin with dycal instrument
stimulates reparative dentin formation - 131what is an example of a base, how do we place, and what does is do?Glass ionomer (vitrabond)
placed in deep areas away from margins, via 2 paste system and light curing
liberates fluoride to inhibit reccurent caries and insulate - 132what are types of densensitizers under amalgam?Copal resin: inexpensive and quick, but leaves film
unfilled, dentin bonded resins: middle cost, more than one step, acid etching, film
gluteraldehyde and HEMA (glumma): no film and one step but expensive and caustic to soft tissues/pulp. should be dried with air - 133what is UMKC policy on dentin desensitizerssmear layer usually seals dentinal tubules
use glumma on especially sensitive tooth after placing a ilner or base first in deep preps - 134what should we aim for for occlusion on occlusal amalgamspreserve cusp eats in bottoms of fossae-->long axis forces on teeth
- 135convergence in a class ii amalgamlingual and buccal wall of box: 3-4* convergence
convex axial wall
45* axiopupal line angle - 136class II amalgam prep open contactsgingival contact: .5 mm
buccal/lingual contact: .2 - .5 mm - 137an open sigmoid shape in the outline form of the buccal side of a class II prepreverse-S curve
- 138what does reverse S-curve accomplish?1. smoothly rounded outline form (resistance to amalgam fracture)
2. Keeps narrowest part of prep away from axiopulpal line angle (2 places most likely to fracture)
3. Allows prep to break contact on buccal side of box but also allows buccal wall to meet tooth surface at 90* cavosurface angle - 139what are the objectives of Class II prep?1. include all caries, existing restorative material and undermined enamel
2. create 90* cavosurface margins on all box walls
3. ideally, create no more than .5 mm clearance with adjacent proximal surface facially, lingually, gingivally - 140purpose of retention grooves in class IIretain amalgam in box from interproximal displacement
grooves do not go into gingival floor - 141exception for class I and class II preps on first premolar?crown tilts lingually so prep should enter parallel to long axis of crown not root
- 142how should you remove caries on an axial wall, pulpal floor, or boxdon't deepen the entire wall or floor, just scoop out the caries or create a box within a box
- 143how much natural structure should support a restorationa tripod
do not cover floor with CaOh--> too soft to support restoration - 144functions of a good matrix band1. enough rigidity resist deformation but is burnishable and displaceable to allow for contact
2. assists in est. contour
3. must prevent leakage of amalgam creating gingival overhang
4. Convient to install
5. easy to remove - 145how can you close the an open margin between a matrix band and toothuse a wooden wedge at the more open embrassure (lingual)
- 146what is ideal marginal ridge form for class II amalgamtriangular inclined plane descends from ridge crest to pit and deflects food to occlusal surface
marginal ridge has straight area perpendicular to long axis of tooth-->long axis forces - 147what is ideal fossa form for class II amalgamcarve anatomy so that occlusal stop in MIP is in the bottom of the fossa --> long axis forces on teeth
- 148how should attempt restorations in quadrant dentistryrestore alternate teeth first, eliminate over contours, then restore the rest
- 149describe special mandibular 1st premolar prepprep should incline lingally to paralel long axis of tooth crown. includ only pit adjacent to box to preserve transverse ridge
- 150describe special maxillary first molar prepcreate a central fossa prep parallel to long axis of tooth and a distolingual groove prep (considered class I even though it is 2 surfaces) with a distolingual tilt to avoid distolingual cusp
leave oblique ridge if it is at least 1 mm wide - 151describe preparations in estethic zonenot necessary to open contact a full .5 mm, keep margin back in embrasure, barely breaking contact
- 152how can u deal with a small distal cusp in mandibular first molar1. create ideal outline form avoiding it
2. include cusp in prep
3. cap cusp - 153box only prepfor small interprox carries with no pit and fissure grooving and no previous occlusal restoration or occlusion on marginal ridge
create retention grooves all the way up to occlusal surface - 154slot preparationused for root caries on interproximal surface of tooth with gingival recession
approach from facial or lingual horizontally and place retention grooves - 155rotated teethconsider using slot prep or other methods to approach malpositioned teeth
- 156how should you approach adjoining restorationsprepare in a way that doesn't leave existing restoration weak
when joining class V and class II, may be able to prep and restore class II first - 157how should you restore a class VI prepfill with bonded composite resin--in this case, composite will strengthen the tooth
- 158any substance other than a drug that can treat, augment, or replace a tissue or function of body (all dental materials which involve exposure to pt)biomaterial
- 159types of primary bondsionic, covalent, metallic
- 160electrostatic attraction of + and - charges involving electron transfer between ions Prop: non directional, strong bonds (100-200 kcal/mol); no free electrons so good thermal and electrical insulators ex: crystal, ceramics, gypsumionic bonds
- 161valence electrons shared by 2 different atoms Properties: directional bonds (50-100 kcall/mol); high electrical and thermal conductivity due to free e, water insoluble ex: water, diamond, polymerscovalent bonds
- 162cluster of positive metal ions surrounded by gas of electrons Props: non-directional bonds (100 kcal/mol), hi electrical and thermal conductivity ex: amalgam and gold alloymetallic bonds
- 163examples of secondary inter atomic bondshydrogen bonds, van der walls
- 1644 types of material propertiesbiological
surface
physical
mechanical - 165biological response to a material in contact with human body ex: allergiesbiological properties
- 166unique properties of a material associated with its surface ex: surface nrg or tension, surface wettingsurface properties
- 167properties dependent on type of atoms and bonding present in material size or shape has no effect (structure insesitive) ex: color, electrochemical, thermalphysical properties
- 168rxn of a material to the application of external force (load) size and shape affect (structure-sensistive)mechanical properties
- 169develops in material to oppose a load =load/area increases with a higher load in smaller areastress
- 170stress of material at fracture dependent on type of force applied ex: compressive, tensile, torsion, shear, flexurestrength
- 171measure of stress necessary to fracture a material by 2 opposing forces directed toward each other usually high even in brittle materialscompressive strength
- 172measure of stress necessary to fracture a material by 2 opposing forces directed away from each other tends to be lowest value in brittle materialtensile strength
- 173twisting, compound stress used in dental implant teststorsion
- 174stress necessary to rupture a material by two opposing parallel forces directed toward each other not in same plane intermediate between compressive and tensile strengthshear strength
- 175measure of stress to cause failure in bending 3 point bend testflexural strength
- 176combo of compressive and tensile stres somehow realted to flexural strength??compressive load
- 177occlusal load/ occlusal contact area minimized by trapezoidal occlusal contact worsened by premature occlusal contactocclusal stress
- 178change in shape or deformation that occurs in a material when load is applied exists whenever stress does change in length/unit original lengthstrain
- 179point on a stress/strain diagram associate with material fracture (strength)final stress point
- 180temporary distortion of a material by a load. when removed, returns to original shapeelastic strain
- 181permanent distortion of a material by a force beyond elastic limitplastic strain
- 182deformation below elastic limit impression materialselasticity
- 183plastic deformation from tensile strength beyond elastic limit ortho wireductility
- 184plastic deformation from compressive strength beyond elastic limitmaleability
- 185minimal to no plastic deformation ceramic and porcelainbrittleness
- 186stiffness of material within elastic range important for restorations--> minimal flexure under occlusal loadselastic modulus
- 187energy absorbed to reach elastic limitresiliance
- 188energy absorbed to cause fracturetoughness
- 189properties of ceramicstrong and stiff
low elasticity
brittle
low resilence and low toughness - 190properties of metal/alloystrong, stiff
some elasticity
ductile
hi resiliance, hi toughness - 191why are ceramics as strong as metals but not as toughionic bonds in ceramincs will repulse during bending-->fracture
metallic bonds will not repulse-->plastic deformation - 192properties of dental composite1. weak
2. not modulus
3. brittle
4. resiliance = toughness
both low - 193properties of elastic polymerweak
low modulus
elastic
ductile
resistant
toughness varies - 194mix of mercury with any other metalamalgam
- 195silver in amalgamincreases strength and decreases amalgam flow
- 196tin in amalgamdecrease setting expansion
- 197copper in amalgamstrengthen silver-tin allow, incr corrosion resistance, less suceptible to creep
- 198zinc in amalgamcauses expansion with moisture
less brittle, 02 scavenger - 199indium and palldium in amalgamreduces corrosion
- 200compare alloy particle geometry of amalgamlathe: more Hg to wet powder, more condensation pressure, roughest surface
Spherical: less Hg, more plastic and harder to develop interprox contact, smooth
Admixed: better condensation, intermediate Hg and smoothness
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- Operative Fichas sobre Operative test 1, creado por Katie Hayes el 01/02/2019.
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