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Fixed Pros II > week 6- Cementation > Flashcards

week 6- Cementation Flashcards

1
Q

what are the steps for delivering the final prostheses before seeing the patient

A
  • evaluate the framework/final prosthesis
  • any need for remake or alteration
  • may any adjustments prior to the patient appointment
  • check the prosthesis for:
  • proximal contacts
  • internal surface
  • marginal adaptation
  • inter abutment stability
  • occlusal contacts
  • occlusal anatomy and finish
  • axial contours
  • overall design
  • clean the prosthetic for patient try in
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2
Q

what should you look for in your framework prior to patient appointment

A
  • metal ceramic finish lines
  • framework design to support porcelain
  • pontic contours
  • connector location; dimension, contour
  • adequate cut back for porcelain
  • adequate metal thickness in areas to be veneered
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3
Q

what frameworks is it necessary to try in to ensure the fit prior to porcelain veneering

A

metal ceramic or zirconia based

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4
Q

framework is tried in to check:

A
  • proximal contacts
  • internal fit
  • marginal integrity
  • stability
  • occlusion
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5
Q

when is shade selection confirmed

A

at the framework try in appointment

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6
Q

once ceramic is veneered at try in you should check:

A
  • same things as when framework was tried in
  • any adjustments needed like occlusion or contacts
  • patient approval and acceptance and consent for cementation
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7
Q

before removing the temporary what should you do

A

take an impression of the temporary to save you time just in case you need to remake a temp, especially if you adjusted the first temp a lot. it also might help remove the old temp

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8
Q

how should you remove the temporary

A
  • using curved hemostat gently rock the temporary back and forth to break the current seal
  • grasp the temporary in a manner in which the temporary is not likely to break
  • clean out the inside of the temp, disinfect it and set aside
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9
Q

before removing the temporary always make sure you have either:

A

the temporary matrix or take a new one

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10
Q

if the temp doesnt come off what do you do

A

section it off

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11
Q

how should you take a temp off teeth with an RCT, post or build up

A

section it off and cut it off with a bur

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12
Q

if the temporary does not come off easily or you are concerned at all about the materials and their stability under the temp what should you do

A

section it off

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13
Q

how should you section a temp bridge off and what should you use

A

use a very thin tapered diamond to section M-D and B-L and then gently remove the sections by applied lateral force in between the criss crossed lines you just made

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14
Q

once the temporary is removed:

A

-clean off any excess cement chunks
- clean the tooth preparations with pumice slurry

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15
Q

if the framework wobbles or rocks on the preparations what should you check

A
  • proximal contacts
  • internal surface
  • margin adaptation
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16
Q

how should you evaluate proximal contacts

A
  • evaluate visually and with floss or shimstock
  • mark areas and adjust as needed if contact is inhibiting full seat
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17
Q

how should you check the internal surface

A
  • use “fit checker” or similar to check internal surface
  • adjust any “positive” areas
  • only minor adjustments should be made in the internal surface
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18
Q

what does a positive defect in checking the margin mean

A

there is too much framework material and this can be polished away with a stone or rubber wheel to see if this allows the rock to disappear

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19
Q

what does a negative defect means when checking the marginal adaptation

A

you have an open margin and a new impression will need to be taken

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20
Q

if the framework is still rocking, the contacts are appropriate and the internal surface is not hindering the seat then what is wrong with it

A

the framework may be distorted

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21
Q

what should you do if the framework is distorted

A
  • section the framework through a connector
  • evaluate each retainer separately
  • if individually each retainer fits, move forward with solder technique
  • if individually either retainer still wobbles or rocks, take a new impression
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22
Q

if the framework is sectioned the cut should be:

A
  • at least 0.2mm wide
  • flat
  • have parallel sides
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23
Q

what do you do after you section the distorted framework

A
  • to make sure retainers are solidly placed and stationary make a Duralay relation
  • once Duralay has set, evaluate framework to make sure rocking or wobble has been removed
  • make a plaster “pick up” index after duralay is set to stabilize the framework as you send it to the lab
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24
Q

once framework returns from soldering at the lab what should you evaluate on the framework-

A
  • proximal contacts
  • internal fit
  • marginal integrity
  • stability
  • occlusion
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25
Q

if the permanent prosthesis seats properly what should you do

A
  • first take a pre veneering radiograph to confirm margins
  • then take a shade and send it back to the lab for porcelain veneering
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26
Q

what are the phases in the lab script

A
  • please pour impression, pin and section cast, articulate master cast with enclosed opposing cast using interocclusal record. return for die trimming and evaluation of articulation
  • please fabricate metal- ceramic framework using noble alloy as follows. return in one piece for framework try in:
  • phase 3: please add porcelain to complete FPD according to above specifications
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27
Q

what are the steps in delivering the final prostheses with the metal and porcelain

A
  • remove the temp, clean and prepare teeth for seating by making sure all temporary cement is removed and tooth has been pumiced
  • try in framework and check for marginal adaptation, pontic adequacy and any rock or wobble
  • take a pre cement radiograph to confirm margins
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28
Q

what is fit chekcer used for

A

to determine if any part of the prep or intalgio surface needs to be adjusted to enable full seating of bridge

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29
Q

what would you do with an open proximal contact

A

send back to the lab to add on more porcelain

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30
Q

what tissue contact with the pontic should you be looking for

A
  • passive contact with the tissue
  • slight blanching of the tissue is acceptable
  • more than slight blanching adjust the pontic/tissue contact
  • if adjustment is made this tissue portion needs to be highly polished
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31
Q

when the bridge fully seats, has floss and pontic fit is acceptable next is:

A

occlusion

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32
Q

check occlusion in:

A

MI, lateral and protrusive movements
- canine guidance should be maintained

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33
Q

anterior bridges need to have appropriate length in protrusive to protect against:

A

porcelain chipping

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34
Q

how should esthetics of the final prostheses be evaluated

A
  • look at the angulation of the facial
  • step back and view the patient from several feet away
35
Q

when do you ask the patient if they are happy with the esthetics

A

after you, the dentist, are happy with the esthetics

36
Q

when is the patients approval signed as consent signed

A

prior to cementation

37
Q

final step prior to cementing is:

A

polishing and finishing

38
Q

how are metals polished

A

brown and green polishers
- green polishers work very well
- brown is course
- green is fine
- two step polishing

39
Q

what do you need to stay away from when polishing and why

A

at the ceramic metal junction because the colors can stay in the porcelain and contaminate the porcelain porosities, it will look ugly

40
Q

if it is necessary to smooth or polish at the metal- ceramic junction:

A

the burr/stone should be help perpendicular to the junction otherwise, the metal particles contaminate the porcelain decreasing the esthetics
- and move side to side not up and down
- if you have to move up and down make sure the bur is spinning away from the incisal edge

41
Q

how should you polish porcelain

A

margin adjustment should be made perpendicular to the margin and rotation of polisher should be toward bulk of material

42
Q

which material is easiest to polish prior to cementation

A

porcelain

43
Q

how should you adjust ceramic

A
  • use gentle forces when inserting and testing the fit of the bridge
  • do not overheat/create excess vibration. this leads to microcracks and tends toward fracture
  • use fine diamonds
  • use separate instruments for metal and porcelain
  • polish porcelain with diamond rubber points and then a fine diamond impregnated polishing paste
44
Q

why is it important to keep as much anatomy as possible while adjusting metal or porcelain

A

it can lead to poor occlusion in other areas and can cause occlusal disharmony

45
Q

what is another name for conventional cements

A

luting cements

46
Q

what are the conventional cements

A
  • zinc-oxide eugenol (temporary cement): Temp bond
  • zinc polycarboxylate (temporary cement): Durelon
  • zinc phosphate cement: gold standard all cements are compared to
  • glass ionomer cement
  • resin modified glass ionomer: Rely-X-Luting
47
Q

what does luting mean

A

the use of a moldable substance to seal a space or to cement two components together

48
Q

what are the advantages and disadvantages of luting cements

A
  • A: adhesion to tooth substance and alloys, easy manipulation, strength, solubility, firm thickness properties comparable to zinc phosphate, fluoride release
  • D: needs accurate proportioning, critical manipulation, lower compressive strength, greater viscoelasticity than zinc phosphate, short walking time, clean surfaces needed for best adhesion
49
Q

what is another name for resin based cements

A

adhesive cements

50
Q

what are the resin based cements

A
  • adhesive resin cement with dentin bonding agent: total or selective etch
  • self etch: self etching primer with no extra dentin bonding agent
  • self-adhesive: no etch, no additional dentin bonding agent needed but does require a primer
51
Q

which resin cements bond to the tooth

A

self etch and self adhesive
- SpeedCem Plus

52
Q

what are the advantages and disadvantages with resin based cements

A
  • A: high strength, low oral solubility, high micromechanical bonding to dentin, alloys and ceramic surfaces
  • D: need for meticulous and critical technique, more difficult sealing, higher film thickness, possible leakage, pulpal sensitivity, difficulty in removal of excess cement
53
Q

describe adhesive resin cement

A
  • requires use of dentin bonding agent
  • dentin bonding agent bonds to tooth and resin
  • cement bonds to dentin bonding agent
  • most esthetic cement system
  • most retentive
  • used for veneer restorations mostly
54
Q

describe self etch adhesive resin

A

cement does not require a separate dentin bonding agent but requires tooth pre treatment in the form of a primer

55
Q

describe self adhesive resin

A

cement requires no dentin bonding agent nor does it require a self etch primer pre treatment
- resin cement interacts directly with the tooth surface
- generally creates higher bonds to dentin

56
Q

what are the considerations when using resin cements on all ceramic restorations

A
  • resin cements require a moisutre free environment
  • required for low strength glass ceramics
57
Q

what are the considerations for RMGI with all ceramic restorations

A
  • RMGI cements are contraindicated with low strength glass ceramics
  • the RMGI ceramics absorb water and expand as they set which could cause fracture of ceramics especially at margins
  • need adequate retentive preps
  • RMGI is great with metal, PFM and zirconia restorations
58
Q

why are RMGI cements recommended for eMax crowns

A

to offset the brittle nature of glass ceramic

59
Q

when are RMGI cements used

A

with IPS eMax when tooth preparations are sufficiently deep axially and with margin thickness of at least 1mm, retentive mechanically, and patients are highly caries prone

60
Q

what are the steps to determine which type of cement to use

A
  • type of material
  • design of material
  • tooth prep and location - retentive vs non retentive prep
  • additional factors: caries prone patients, weird occlusion, moisture isolation, clencher or grinder
61
Q

what cement has the most to least amount of steps

A

adhesive cements > self adhesive cements > conventional cements

62
Q

what cement requires the most retentive prep to least

A

conventional cements > self adhesive cements > adhesive cements

63
Q

In PFM cementation with adequate preparation retentive features what cements can be used and what is the most commonly used

A
  • zinc phosphate
  • glass ionomer
  • RMGI - most common
64
Q

in PFM cementation without totally adequate preparation retentive features, wacky occlusion, or bruxer what cement is used

A

resin cement - either dual cure or self cure

65
Q

what is the cement of choice with glass ceramics

A

resin cement- dual cure or self cure

66
Q

what is the restoration pre cementation treatment for ceramics

A
  • internal surface: HF acid etch to roughen for micromechanical retention for eMax or feldspathic porcelain. done by lab. sandblasting or diamond bur roughening would damage the surface of these ceramics
  • silane treatment in internal surface to enhance the chemical bond between glass/ceramic/resin cement
67
Q

what cement is used in zirconia cementation with adequate preparation retentive features and what is most commonly used

A
  • zinc phosphate
  • glass ionomer
  • RMGI - most common
68
Q

what cement should be used in zirconia cementation without totally adequate preparation retentive features, wonky occlusion or bruxer

A

resin cement

69
Q

what is the internal surface pre treatment for zirconia

A
  • abrasion needed. lab leaves internal too smooth
  • air abrasion or diamond bur leaving horizontal roughened lines on internal walls
70
Q

in zirconia cementation adhesive promoting agent can be used but must contain:

A

MDP

71
Q

what is the adhesive promoting agent made of in zirconia cementation

A

methacryloyloxydecyl dihydrogren phosphate

72
Q

what is the downside of eugenol

A

inhibits polymerization of any composite resin

73
Q

what removes eugenol residue

A

acid etchant

74
Q

what does provisional cement residue do

A

occludes tubules and decreases effective bonding

75
Q

what does cleaning the tooth with pumice do

A

removes the temporary cement residue

76
Q

what should the patient close down on to seat the crown

A

soft cotton roll, not anything hard because it leads to fracturing

77
Q

if occlusion does not permit solid pressure for crown seating:

A

firm pressure from finger is used to fully seat the crown until cement has cured on its own or it has been light cured

78
Q

when using a curing light for resin cement, seat the crown full of cement and:

A

tack the cement

79
Q

what is tacking the cement and why do we do it

A
  • turn on your curing light while on the facial margin and immediately turn it off
  • place the curing light on the lingual and turn it on and immediately turn it off
  • this allows you to partially cure the cement so it peels away
80
Q

what happens if you cure fully with too much excess

A

it will be very challenging to be able to remove all the cement
- youll need high speed handpieces

81
Q

once excess cement is removed with hand pieces:

A

floss to remove interproximal excess
- once all cleaned, fully cure on facial and lingual and move light around to cure interproximal areas too

82
Q

now that prosthesis is cementeD:

A

-Recheck occlusion
- adjust if necessary: use a fine diamond to avoid excess heat
- polish with diamond impregnanted discs or points
- take a post cementation radiograph
- discuss OHI with patient

83
Q
A

Fixed Pros II (13 decks)

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