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Build up and foundation Flashcards

1
Q

Liner

A

Materials that are placed as a thin coating (usually less than .5mm on surface of cavity preparation.)

although they provide a barrier to chem irritant they are NOT athermal insulator or used at bulk

Ex: dical, vitrabond

these materials dont have sufficient hardness or strength to be used alone in deep cavity.

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2
Q

type of liners

A 
Varnishes
Calcium Hydroxide
Glass Ionomers
Resins
Resin-modified Glass Ionomers

ex. vitrabond is resin modified

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3
Q

Varnishe types

A

copalite,
duraphate (colgate oral phram)
suraflor (pharmsicnence)

(last 2 a for sensitive cervical lesions, they are fluoride varnishes)

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4
Q

CaOH

A

pH 11
Basicity inhibits bacterial growth and neutralizes acidic bacterial byproducts

Pulpal irritant that stimulates the formation of reparative dentin

Extracts growth factors from the dentin matrix to produce dentin bridge

*good for endo, protects and stimulates secondary dentin

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5
Q

Calcium hydroxide types

A

Dycal (Dentsply Caulk)
Prisma VCL Dycal (Dentsply Caulk)
Life (Kerr)
TheraCal LC (Bisco) resin-modified calcium silicate – Ca2+ in basic environment

*dycal we use in clinic

use when pulpal exposure may even happen but use dycal and cover it

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6
Q

Glass ionomers

A

Form ionic bond between carboxylates and calcium in the dentin and enamel

Provide sustained fluoride release to counter the effects of microleakage

Should **not be used as pulp capping agents

The most common formulations are now in the form of resin-modified glass ionomers

Very moisture sensitive until set

Also can be damaged by desiccation, especially during setting

(so remember cant contaminate with saliva and cant blast with air you cant contaminate or air it)

ketac and fuji are examples

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7
Q

Resin properties

A

resins are :
high compressive strength
high tensile strength
low solubility

*NOT recommended for direct pulp capping

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8
Q

Bases are

A

Can be considered as restorative substitute for the dentin that was removed by caries and/or the cavity preparation.

Are generally thicker than a liner.

Act as a barrier against chemical irritation, provide thermal insulation, and can resist the condensation forces on a tooth when placing a restoration.

Can be shaped and contoured after placement into the cavity preparation.

Are often used to build out to “Ideal” in preparation for either the direct or indirect restorative material.

(something there to restore whats missing- helps build to the ideal for a future build up)

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9
Q

Base types

A 
Reinforced Zinc Oxide & Eugenol (IRM)
Zinc Phosphate (Flecks)
Zinc Polycarboxylate (Tylok Plus, Durelon, Hybond, etc…) --> a permanent cement..only way to get it off is to blast it off.

Glass Ionomer (Ketac Fil Plus, Fuji II Core Material, etc…)
Resin (Core Paste, Luxacore, Compcore, etc…)
Resin Modified Glass Ionomer (Vitremer)

(dont leave Eugenol under composite because it will SOFTEN RESINS!)

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10
Q

Why build up?

A

Enhance connection of indirect restorative material to existing tooth structure.
Permit the creation of ideal retention and resistance form in the crown preparation.
Should help to direct occlusal forces axially.
Eliminate undercuts to allow a line-of-draw for the indirect restoration.
Reduce the volume requirement of the indirect restorative material (more significant if working with Au alloys).

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11
Q

Build ups also

A

Generally involve a greater volume of material than a base.

Can be placed over liners with vital teeth.

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12
Q

Build ups for vital teeth

A

First, Is a build-up necessary?
Maybe, if substantial portions of coronal tooth structure are missing.
Yes, if over ½ of coronal tooth structure is missing.

Then, answer this question: Can this tooth be predictably restored without a post? if answer is no then do a root canal.

Will pins or retentive grooves/pot holes be necessary?

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13
Q

cover protect and seal

A

important facts for buildups

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14
Q

both pins and posts

A

dont strengthen teeth but just thsorten the conneciton

only put post in endo resotred tooth if indicated. small iamter of ttooth is greater chnaceo f post due to endo.

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15
Q

Ferrule is key at how many mm?

A

2mm!

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16
Q

When are posts usually deemed unnecessary?

Should we remove tooth structure to get a stronger post?

A

when adequate coronal tooth structure is present to retain a core

NO

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17
Q

Thinnest post w/ adequate strength is :

A

recommended

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18
Q

for best retention it was found that post surface should

A

NOT BE SMOOTH

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19
Q

Remaining coronal tooth structure was found tohave the highest correlation in regard to success of final restoration of

A

endo treated teeth

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20
Q

The survival of endodontically treated, maxillary anterior teeth, restored with full-coverage ceramic crowns, is more dependent upon

There was _____between parallel and tapered glass-fiber posts.

A

retaining three to four walls of coronal tooth structure than on the shape of the post.

little difference

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21
Q

Maxillary Incisors with compromised roots restored with

A

cast posts had fracture strength values more than twice that of the fiber post groups

However, all the fractures resulted in unrestorable roots.

With prefabricated posts where resin filled the space between the post and the flared root walls, 60 to 80% of the failures resulted in non-restorable root fractures

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22
Q

PFM is best way to cover a

A

endodontically treated tooth

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23
Q

2mm ferule helps exhibit stronger and high fracture strengths

A

when restored with all ceramic crowns indep of ferrules

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24
Q

ferrule is more important in custom cast post core than in prefabricated post and composite core

A

.

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25
Q

Overall strongest combination in studies are casta and post core and

A

pfm crown with 2 mm ferrule

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26
Q

Ferrule affect

A

in endo treated teeth positvely affect the fracture strength of fiber post

27
Q

post length

A

stidy indicates that ferrule effect and stiffness of post NOT POST LENGTH have a critical effect on dentin stress levels.

28
Q

“for the cast post and core, the shear stress at the interface was mainly produced in the post end area, which increased with decrease of post length.”

A

Shear stress is usually directed at 135° degrees to long axis of tooth.
Increased post length decreased shear stress at apical end of post.

*shorter post transfers more stress to end of the post or canal, so longer posts are better typically.

29
Q

The magnitude of shear stresses was influenced by post length.
Peak shear stresses increased substantially as post length was decreased.

A

..

Conversely, shear stress decreases as post length increases.

30
Q

The length of the post has a significant effect on its retention and in most instances, the more deeply the post is placed,

Posts with a length of at least 3-quarters of the length of the root offered

Short posts are especially dangerous and have a much higher failure rate.

A minimum of ____ gutta percha must remain to preserve the apical seal.

A

the more retentive it becomes.

the greatest rigidity and least root deflection (bending) when compared with posts that were a half or a quarter the root length.

of 4 to 5 mm ``

31
Q

what kind of posts should we want

A

“select a post that is as long as possible within the long axis of the tooth, and of a minimum diameter to maximize preservation of remaining dentin.” we want 2/3 length of the root

too short is when it is 1/3 or length of the root

32
Q

Many factors that influence your decision on post length
Exercise caution in curved roots
Exercise caution when navigating the canal with your post drills
Ideal post length is probably between 2/3 to 3/4 the total length of the root
Remember: Must also maintain minimum of 4 to 5 mm of gutta-percha at apex

A

,,

33
Q

tapered posts produce

parallel posts generated their greatest stress at the

A

greatest stress at coronal shoulder

apex of the canal prep

34
Q

Parallel posts resisted tensile, shear, and torquing forces better than tapered posts and distributed stress more uniformly along their length during function.

Several studies have reported that a well-adapted, passively luted, parallel-sided post provided the most retentive post with the least stress.

A

..

35
Q

the parallel-sided, serrated, vented post produced stresses that were distributed most uniformly along its length and appeared

Tapered self-threaded screws are the most likely to cause

A

best able to protect the dentin.

stress fracture and are not recommended.

36
Q

Dentin stresses were reduced by:

A

Bonding the dowel

increasing modulus of elasticity of the dowel

increasing diameter of the dowel

increasing length of the dowel
parallel sided dowels

*glass fiber post has increased modulus of elasticity

37
Q

A parallel post with a tapered apical end may be the best overall, and most universally appropriate post shape.

A

..

38
Q

The lentulo spiral is the superior method of placement for most cements. (Not with RelyX Unicem)

The luting agent may also be placed in the canal with a needle tube, as long as the tip of the tube is inserted to the bottom of the canal space and the material is extruded from the tip as it is slowly removed from the canal.

After the luting agent is placed in the canal, the post can be coated with the luting agent and inserted.

A

Relyx in clinic (material in clinic with its consistency a lentulo wont work, got put in canal and pump it and introduce it again )

39
Q

“The most reliable results in fiber post cementation are obtained by etch-and-rinse adhesives in combination with dual-cure resin cements.”

A

there are self adhesive resins (realx unison) but these are lower in comparison to etch and rinse adhesives

bottom line: you want the canal clean rinsed drie

40
Q

“Resin-reinforced glass ionomer cements demonstrate some excellent properties; however, there has been a suggestion of post-set expansion that may make this cement unsuitable for post cementation.”

A

SO never use a RMGI as a cement

41
Q

Self adhesive rein cements are less technique sensitive but

A

lower in comparison to etch and rinse

42
Q

Delayed cememntaiton of fiber post at least 24hr post endo treatment results in

A

resulted in higher retentive strengths in comparison to immediate cementation and the best results were obtained when the luting agent was brought into the post space with lentulo spirals or specific syringes.

so wait a day!

43
Q

Resin cement thicknes

A

not larger than .3mm

44
Q

in oversized canals bonding the posts with the ___

A

core build up material is probaly indicated

45
Q

cements are better for

core are better for

A

crown seating

build ups

46
Q

RESULTS: self-adhesive resin cements exhibited significantly higher bond strengths than the self-etching resin cement.

A

.

47
Q

preserve these guys for long term post endo restoration

A

tooth tissue, ferrule effect, adhesions

48
Q

fiber posts

A

are the best way to go

49
Q

preservation of tooth structure is a must

posts should NEVER be used with the intention of reinforcing the tooth

review of functional and parafunctional forces must be undertaken before restoring the tooth, as these will influence the prognosis

A

.

50
Q

MOST Common failure is caused by

A

fatigue fracture

51
Q

Abutmments cement and reoncstruction are all subjected to stress caused by

A

occlusal force and fatigue grcture may occur at the weakest point of where the maxium stress occurs

52
Q

Weakest point is freq in connection

A

with endo tx teeth restored with post and cores

53
Q

The literature points to nonaxial forces as a risk for fatigue fracture of teeth, cement, and restorative material.
Favorable occlusal prosthesis design is probably more important for survival of structurally compromised endodontically treated teeth than is the type of post used.

A

.

54
Q

The technique:

A
  1. Remove all damaged tooth structure including caries, fractures, etc…
  2. Test the integrity of any remaining pillars of tooth structure by applying moderate lateral force with an instrument.
  3. Where possible, eliminate non-axial loading of build-up against tooth.
55
Q

Build-up cores should be supported by flat tooth structure that delivers a purely compressive force upon axial loading.

Remove weakened axial walls prior to core build-up.

A

.

56
Q

To eliminate non-axial loading:

A

create near horizontal and vertical planes of tooth structure with no sharp line angles as they can create points of stress in both dentin and the build-up material . (steps)

Slight truncation (undercut) is favorable for retention of the build-up.

Spicules of dentin less
than 2 mm in width are usually best eliminated.

57
Q

After extensive loss of tooth structure, vital teeth can be built up completely with composite restoration material.
Sometimes, the use of additional retentive features, such as pins, potholes and grooves, is indicated.
In exceptional cases, root canal therapy may be indicated, allowing the utilization of a post to aid in the retention of a build-up core.
Endodontically treated multi-rooted teeth can be built up entirely with composite, utilizing the pulp chamber and root canal access for retention.
in single-rooted teeth, a post is usually necessary to reinforce the retention of coronal tooth structure to the root.

A

..

58
Q

type of pins

A

Cemented
Friction Locked
Threaded

59
Q

Pin Placement

A

-Advise patient that pins put tooth at endodontic risk
Place only when absolutely necessary

  • Be aware of your dental anatomy!***
  • Best locations are usually at line angles
  • Place approximately 0.5 to 1.0 mm inside of DEJ (1/4 round pilot hole)
  • Parallel outer surface of root
  • Hand placement only – DO NOT DRIVE IN WITH SLOW SPEED MOTOR!**
    Less likely to strip threaded dentin
    Less internal stresses introduced into dentin
  • If necessary, bend pin to be contained largely within core of build-up
60
Q

Drill techqniue

A

¼ Round Pilot Hole
Place tip of pin drill into pilot hole.
Orient angulation, mesio-distally and bucco-lingually to avoid PDL and pulp.
At slow speed, penetrate into dentin ½ depth of threads on pin drill.
Pull out.
Again at slow speed, penetrate now to full depth and remove.
DO NOT OVER-PREPARE!

61
Q

Post preparation

A

Start with a Gates Glidden #2 or #3
Keep minimum of 5 mm of Gutta Percha to maintain apical seal
Confirm with radiograph if necessary
Watch for Gutta Percha at end of drill to help confirm position within canal
Allow drill to follow path of least resistance

62
Q

Posts were deemed to be unnecessary when adequate coronal tooth structure was present to retain a core.
Do not remove additional tooth structure in order to construct a stronger post.
The thinnest post with adequate strength was recommended.

For best retention, it was found that post surfaces should not be smooth.
Remaining coronal tooth /occlusal forces structure was found to have the highest correlation in regard to success of the final restoration of endodontically treated teeth.

A

remember post surface should NOT be smooth for best retention

63
Q

Bonding the post

A

Condition the tooth surface for bonding, including the canal
Thoroughly dry tooth,

including canal with paper points

Mix cement and apply according to manufacturer’s instructions
Insert post

FP (11 decks)

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