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Fixed Pros I > Restoration of Extensively Damaged Vital Teeth > Flashcards

Restoration of Extensively Damaged Vital Teeth Flashcards

1
Q

what are the central core guidelines

A
  • pulp and 1 mm thick surrounding layer of dentin should be preserved if possible
  • retentive features should not be cut deeper than 1.5mm at cervical line or central fossa -2mm
  • auxillary retentive features ideally kept in “safe zone”
  • caries removal: deeper areas filled with base
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2
Q

what happens to the central core as we age

A

it shrinks and receds

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3
Q

what 5 categories are involved in decision making

A
  • deciding on the type of restoration to use
  • using defects as retentive features
  • pin placement and retention
  • bases and cores
  • tooth preparation procedures
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4
Q

what restoration do you use with extensive peripheral destruction

A

full crown

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5
Q

what do you do with an isthmus destruction greater than 1/2 intercuspal width

A

inlay or onlay

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6
Q

what do you do when more than 50% of tooth structure is gone and loss of cuspal support

A

crown and likely a core build up too

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7
Q

what do you do with a less destructive central lesion

A

inlay or onlay

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8
Q

what do you do with a large central lesion

A

build up and crown

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9
Q

when would you decide you need RCT

A
  • if pulp is exposed
  • if post is needed for retention of build up
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10
Q

what would qualify as combined extesnive periperal and central destruction

A
  • deep proximal lesions impinging on vital core
  • more than 50% of vital core destroyed
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11
Q

what can you do to increase retention and resistance

A
  • re orientation of sloping surfaces
  • adding grooves
  • adding box forms
  • adding pins with a build up
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12
Q

what can we do to increase resistance form with less than ideal tooth structure remaining

A
  • reduce the total occlusal convergence of the axial walls
  • add grooves
  • add box forms
  • increase wall height
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13
Q

how can you increase wall height

A
  • place finish line more apical
  • pin retained core
  • crown lengthening
  • orthodontic extrusion
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14
Q

how should you reshape axial walls to reduce TOC

A

increased axial reduction in the cervical 1/2 of the preparaion wall

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15
Q

what do you do with sloping surfaces left after cusp fracture or caries removal

A
  • break slope into vertical and horizontal components
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16
Q

what does conversion of a sloping surface into one large vertical wall do

A

weakens the tooth with too much removal and endangers the vital core of the tooth

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17
Q

what should you do in a sloped wall if greater than 3mm vertical wall length apical to the fracture cusp

A

a facial shoulder with axial wall reduction leaves adequate wall legnth for resistance form

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18
Q

describe the grooves that are placed parallel to the long axis of the tooth for resistnace and retention

A
  • at least 1mm wide and deep
  • 0.5mm to 1mm away from the finish line
  • spaced around the tooth
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19
Q

what do proximal grooves do

A

shorten the radius of the arc of rotation

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20
Q

walls of a groove or a box are best placed:

A

perpendicular to the displacing forces

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21
Q

how can box form be used for retention

A
  • remove caries
  • convert caries removal into a box form by squaring walls
  • not needed on intact walls
  • box should be well into dentin to resist displacing forces
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22
Q

when two boxes are needed, less than 180 degrees of tooth circumference remains:

A
  • this poses a great risk for cuspal fracture
  • use a build up and full crown to protect against fracture
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23
Q

what is the risk with placing margin more apical

A

invading the biological width

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24
Q

what do you need to remember to do with a build up

A

finish line needs to be on tooth structure and you still need at minimum 2-3mm of ferrule

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25
Q

how do you remove biological width restriction

A

crown lengthening

26
Q

what does orrthodontic extrusion do

A

extrude the tooth out of the bone to gain some height

27
Q

describe a core build up

A

-replaces lost tooth structure to improve retention of a crown
- a core must be anchored firmly to the tooth and not just palced to fill the void
- retention for a core is often with the use of pins

28
Q

when is a build up needed

A

when more than 50% of tooth structure is lost

29
Q

what are the build up guidelines

A
  • short axial walls: repeated de cementation of crown
  • excessive interocclusal distance- needs pin retained core
  • crown margin needs to be on sound tooth structure
30
Q

describe amalgam as a build up material

A

not retentive but strong
- compressive strength
- dimensional stability
- corrosion- sealing
- isolation technique less senstivie
- often used in RCT teeth into canal for strength

31
Q

describe composite as a build up material

A

retentive but not as strong
- bonds to tooth structure
- still needs help with pins
- tooth prep at same visit
- ease of manipulation
- can be thinner than 2mm
- color of material aids in crown matching

32
Q

when is the use of a pin recommended in a build up

A

if 1/2 or more of the clinical crown has been destroyed

33
Q

when should cusps be shortened or removed in a build up

A

if 1/2 their height are weak

34
Q

for amalgam core, the cavity floors and walls should be _____

A

flattened

35
Q

crown margins in a build up should be at minimum ________ material margin

A

1mm apical to build up

36
Q

what are limitations with an amalgam core build up

A
  • matrix placement can be difficult if tooth is severely broken down
  • slow setting material:10-15 mins before removing band
  • no bonding or natural retention
  • requires at least 2mm thickness
  • color shows through some ceramic crowns
  • final crown prep occurs another day
37
Q

what are the limitations in using composite as a core build up material

A
  • technique sensitive
  • isolation can be challenging
  • microleakage posssible as material shrinks when cured
38
Q

what is the rationale for pins

A
  • pins are helpful to support the build up material when residual tooth structure does not provide adequate retention itself
  • pins increase resistance for build up support
  • the resistance is both internally and apically
  • pins should be placed non parallel
39
Q

what are the guidelines for pin placement

A
  • place in sound, healthy dentin
  • do not damage or undermine nearby enamel
  • angulatin can create problems. avoid perforations or pins into the pulp
40
Q

what happens if the pin is placed in unhealthy dentin

A

the threaded pin will not bite and will just spin in the hole and or fall out

41
Q

how much enamel should be left in pins

A

-flat area of placement
- 0.5 to 1mm from DEJ or axial wall
- at least 0.5mm of dentin should surround the pin

42
Q

what problems do pins introduce

A

-dentin stresses creating micro fractures
- microleakage around the pin

43
Q

what are the guidelines for pin placement

A
  • best used in line angles of posterior teeth to avoid furcation , perforations and the pulp
  • 1 pin per missing cusp, line angle, or axial wall
  • at least 5mm of space between pins
  • max of 4 pins per tooth
44
Q

what is the pin placement procedure

A
  • use pilot drill to make pilot hole, depth gauge is on the drill
  • use slow speed
  • watch angulation and position
  • using filpin latch pin and slow spped handpiece, place pin just in hole, then full rheostat power
  • the pin will snap off at the area of the shaft that has been scored
  • the teeth of the pin should engage in the dentin
  • the pin should not be mobile or able to be easily pulled out
45
Q

describe the self limiting twist drill

A
  • cutting tip and helical flutes
  • 2mm deep
  • one motion without stopping
  • too much wobble or imperfect handpiece technique creates a pilot hole that is too wide
46
Q

if the pin is mobile or pulled out:

A

the dentin is either still decayed or too soft to support a pin

47
Q

how can pins create non parallelism

A

bend them

48
Q

where should pin be during bending

A

in dentin

49
Q

how do you bend the pins

A

bender instruments

50
Q

pins placed in dentin should:

A
  • be 2mm deep into dentin
  • be 2mm coronal into build up
  • minimum 1mm radius of build up still around pin after preparation is done
51
Q

what do you do once pins are placed

A
  • place matrix around prep
  • build up can be placed
  • matrix is removed and now crowm prep can proceed
52
Q

what are the pin complications

A
  • fluted root shape
  • furcation
  • pulp penetration- RCT needed
53
Q

what do you do if pin exits tooth surface above bone

A

flap and smooth to tooth contour

54
Q

what do you do if fractured pin

A

move to another location 1.5mm away

55
Q

what do you do if stripped pin

A

use a larger sized pin

56
Q

what are bases used for

A

to protect pulp in teeth that have excavations that are deep and near the pulp
- to fill undercuts when an entire build up is not needed

57
Q

describe the strength of bases

A

-weaker materials that do not provide strength like a build up
- not strong enough to support grooves, boxes or other retentive features

58
Q

what are the materials for bases

A
  • polycarboxylate cement
  • glass ionomer cement
  • resin modified glass ionomer cement
  • silver reinforced glassed ionomer cement
59
Q

what liner is used with bases

A

CaOH- dycal

60
Q

what is the common protocol/steps for bases

A
  • gluma (gluteraldehyde): 2 x60 sec coats
  • dycal/calcium hydroxide
  • vitrebond
  • glass ionomer
  • routine restoration steps
61
Q

what is the sequence of treatment for extensively damaged teeth

A
  • evaluate periodontal and endodontic health
  • remove all caries or old restorations
  • re evaluate your prep
  • restore
62
Q
A

Fixed Pros I (13 decks)

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