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28 Cards in this Set
- Front
- Back
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list the seven steps of cavity prep in proper sequence
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1.outline
2.resistance 3.retention 4.convenience 5.remove caries 6.smooth walls 7.clean surface |
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importance of outline form
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this refers to placement of cavity prep margins in positions they will occupy in the completed cavity prep. ouline form is influenced by:
extent to which enamel is cariously undermined extent and position of deep non coalesced fissures and pits location of pulp horns masticatory facets and wear strength of restorative material placed esthetics extension for prevention |
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importance of resistance form
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placement and shape of cavity prep walls that best enable the tooth to withstand functional stress on restoration and remaining tooth structure. Resistance form is obtained by:
provision of a seat to withstand stress placement of walls at rt angels to masticatory forces adequate tooth reduction to provide for bulk material removal of all undermined enamel removal of weak cusps |
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importance of retention form
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refers to design of cavity prep that best permits the restoration to resist displacement through tipping or lifting forces of mastication
ex: dovetails, coverging walls, retentive grooves, and mechanical locks |
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importance of convenience form
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refers to shape of prep to allow observation,acess, and ease of operation while restoring the tooth.
influenced by: acess to area extension for prevention location of caries amt of tooth seperation size of instrument used salivation |
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what is removal of remaining caries influenced by?
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extent of caries
state of pulpal health amt of remaining sound dentin |
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importance of finishing enamel walls and margins
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get best marginal seal between restorative material and tooth and provide max strength of both enamel and restorative material at the margins. this step is accomplished by judicious use of sharp hand instruments and is influenced by:
direction of enamel rods prescnece of irregular enamel rods amt of remaining dentin |
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explain extension for prevention
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philosophy that preps should include removal of pits and fissures tht are carious or have deep non colesced fissures
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explain why principle of extension for prevention may be modified in regard to non carious pits and fissures of teeth
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the non carious deep pits and fissures may be treated more conservatively be sealing them w/resin sealant
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list the various elements that may be used to provide retention in cavity preps
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buccal and lingual walls converging slightly
dovetails |
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explain general considerations of ideal class I cavity prep design as they related to the 7 steps of cavity preparation
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make sure to conserve max tooth structure
make prep as thin buccolingually as possible while including all caries but never narrower than smaller condenser smooth cavosurface margins for cleansability |
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discuss guidelins for Class I cavity prep on typodont
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all major pits and fissures of occlusal surface of typodong are cariously involved and must be included in prep but this may not be case in clinical situation
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list and explain criteria that should be met by properly completed calss I occlusal cavity prep
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1.classic outline form
2.all cavosurace margins are on smooth surface 3.ideal isthmus width of size of narrowest condenser 4.sloped proximal-occlusal walls 5.margins flow around cusps 6.no sharp cavosurface angles 7.no cavosurface bevels 8.no margins in wear areas 9.pulpal wall perp to Long axis of tooth 10.pulpal wall at depth of 1.5 mm (.5mm into dentin) 11.pulpal wall in dentin 12.buccal/lingual walls converge 13.all internal walls smooth 14.line angles sharp 15. all debris removed |
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describe variations in class I cavity outlines that might be required man 1 pm
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man first pm: the pulpal wall is not perpendicular to long axis of tooth as it is normally, instead the pulpal wall is parallel to plane running from buccal cusp to lingual cusp. this protects prominent buccal pulp horns. Transverse ridge is maintained when possible
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what teeth require modification in class I cavity prep?
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man 1 pm
max molars |
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describe variation in Class I cavity outline that may be required for max molars
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oblique ridge is maintained whenever possible
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purpose of blacks 7steps of cavity prep
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represent systematic, scientific procedure for efficiency in cavity prep
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what is indication for Class I amalgum restoration?
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caraious tooth structue in occlusal fissures detected clinically and w/BWX
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What are objectives of Tx for Class I amalgum restoration?
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eliminate caries lesions
remove any enamel that has been undermined by caries process preserve as much tooth structure as possible create strong restoration that mimics original tooth structure |
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does presence of deep or stained fissure alone justify placement of restoration?
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no. when there is concern that dentin at the base of a deep fissure may become carious the fissure should be sealed w/flowable resin composite
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what is difference in groove, fissure, and pit?
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groove is linear channel on surface of tooth
fissure is linear cleft. it is result of incomplete fusion of enamel of adjoining dental lobes a pit is a pinpoint fissure of junction of several fissures |
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should grooves that have no fissures or caries be routinely incluede in occlusal outline form of class I cavity prep for amalgum?
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usually in class I amalgum preparation,occlusal fissures, or at least those in dev grooves has been included in prep even when area of fissure system have not been carious
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how does the philosphy of txt toward tx of Class I differ from GV blacks philosophy of extension for prevetion?
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author says that carious denin left at base of sealed fissure does not progress, therefore extension for prevention is not justified
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are majority of restorations completely protected from leakage begween tooth and restorative material?
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most restorations exhibit some leakage at margins although it is minimal.
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what is purpose of extablishing smooth curves in cavity outline form?
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to facilitate the uncovering of the margins during carving of amalgum. margins should not be jagged bc it is difficult for dr to know whether restoration margin appears to be irrecgular bc of enamel or flash
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why is it important to prepare enamel margins at an angle of 90 degrees or more?
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to resist fx
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what is danger for a cusp that is reduced by more than 1/3 of intercuspal distance during cavity prep?
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crack or fx
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what should be done if an occlusal carious lesion is so extensive that it encroaches upon the proximal surface or the marginal ridge of the tooth?
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if an occlusal caries lesion encroaches on the enamel of the proximal surface so that when the carious dentin is removed, the proximal enamel has no dentinal support, consideration should be to convert the Class I to a Class II prep.
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