9. Bases and Liners Flashcards by J L

Effect of Restorative Procedures on the Pulp
• \_\_\_\_ of cavity preparation
• Frictional heat
• \_\_\_\_ of dentin
• Cavitycleansing
• \_\_\_\_ etching of dentin
• Restorative materials
• \_\_\_\_

depth
desiccation
acid
polishing

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Pulpal Response
• Tissue is confined within a ____, unyielding environment (pulp chamber)
• No ____ circulation
– to facilitate removal of irritants and enhance
repair

Therefore, the ____ is more vulnerable to injury than other similar tissues…

rigid
collateral
dental pulp

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Pulpal Response

The remaining ____ from the pulpal extent of cavity preparation to the pulp is the single most important factor in protecting the pulp from insult

dentin thickness

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Pulpal Protection

Many restorative materials that provide excellent properties for the bulk of a dental restoration, may not ____ the dental pulp during ____ or during cyclic thermal or
____ stressing

protect
setting
mechanical

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Pulpal protection
- ____ protection - Leakage of restoration
- ____protection - Dissimilar metals in the mouth like amalgam against gold restorations can cause electrical problems
feeling sensitivity
- ____ protection - don’t want pt to feel pain when eating ice cream or from hot drink > want to protect tooth from thermal changes
- ____ medication - medication can help pulp heal in deeper restorations
- ____ Protection

chemical
electrical
thermal
pulpal
mechanical

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Liners and bases are materials placed
between \_\_\_\_ (and sometimes \_\_\_\_) and the restoration to provide pulpal protection

dentin

pulp

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Pulpal protection
Have an amalgam in the tooth
• if we don’t optibond it, then we are waiting for the amalgam to corrode which seals it
• Another option: bond amalgam to place so ____ can seal. When amalgam breaks down, gap starts to open up and will get recurrent decay
• Good thing about amalgam is that it continues to corrode so it can last for many years and
seal themselves

In deeper restorations where the decay (in red) is close to pulp horn, we can put ____ in and put a ____ where dentin was lost.
• Base (orange) provides ____ protection -> doesnt have to be
condensed hard
• When you condense the amalgam, you are condensing on the ____ and not on the thin dentin
• Also provides ____ protection

interface
medicament
base
mechanical
base
thermal

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Pulpal Protection

There is convincing evidence that ____ growth beneath restorations is the ____ cause of pulpal injury

bacterial

primary

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Pulpal Protection

• Bacteria will penetrate the ____ and ____, which may cause recurrent caries, pulpal irritation, or ____ necrosis.

marginal gap
dentinal tubules
pulpal

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Pulpal hydrodynamics

why is the tooth sensitive?
• if there is ____ movement in the dentin tubules, this can cause pain for pt
• It is a stimuli that induces fluid movement in the tubules where the tubules distort the ____
process in the affront nerves
• As the fluid moves, it pulls on nerve and activates it -> causing pain
• This is why you can do an occlusal adjustment in pt ____ and they are fine
◦Once you go through the enamel and into the dentin, they jump
◦Why? When you go into the dentin, the high speed handpiece is moving fluid into the ____ ->
feel PAIN
◦You can sometimes can in with ____ speed w/o fluid and pt is ok b/c NOT MOVING ____

fluid
odontoblastic
enamel
dentin
low
fluid

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Pulpal Hydrodynamics
• If restoration is not well sealed, fluid flows out ____ and into space between restorative material and tooth surface.
– Stimulus (ex. Hot/cold) causes change in ____ rate, which is interpreted as painful by ____

dentinal tubules
flow
mechanoreceptors

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Objectives of Pulpal Protection

If leakage of chemical irritants from ____ materials or ____occurs

____ complex can become inflamed

To protect against these events, need to seal the outer ends of the tubules along the ____ cavity preparation wall

dental
bacteria
pulp
dentinal

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Tooth sensitivity

Some pts have no caries or periodontal disease, but they have ____ -> will get sensitive teeth
• there are products you can seal the dentin tubules
• ____ use coats the tooth and seals it
• Fluoride (____) can help with sensitivity

sensitivity
oxalate crystals
prevident 1.2%

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Pulpal hydrodynamics

If tubules can be occluded, ____ flow is prevented and ____ cannot induce pain.

Therefore, sealing of the dentinal tubules will decrease temperature senstiivty (generally to ____)

fluid
cold
cold

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Smear Layer
Cutting debris from rotary instruments, which is ____ on the cut surface
Enamel and dentin smear layers are left in ____ for unbonded amalgam restorations
Dentin smear layer produces some degree of ____ sealing

compacted
place
tubule

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Smear Layer
• Very effective barrier
– Limits ____ of potentially toxic substances to pulp
- Cannot be invaded by ____
• But permeable to bacterial ____
• Because it is partially porous, it can not prevent ____ diffusion

This produces ____ protection

diffusion
bacteria
products
slow long-term

chemical

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Smear Layer

All of the decay has been removed here and a smear layer is produced
• there are ____ that seal it
• When bonding, we put ____ here taking the smear layer away, replacing with ____ to bond it

smear plugs
acid
resin

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Terminology

Cavity Sealers:
Provide a protective coating for freshly cut tooth structure of the prepared
cavity. Consist of ____ , ____ and ____ agents.

varnishes
desensitizers
dentin bonding

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Desensitizers
• Gluma
35%____ (hydroxyethyl methacrylate)
5% ____

HEMA is a ____
• it seals the tubules Glutaraldehyde is ____
The combination works very well when pt comes in with no ____ and you don’t think they need an endodontic procedure.
• put Gluma on and pt feels great and wont feel ____
when they rinse with water -> no pain anymore

HEMA
glutaradehyde
resin
antibacterial
caries
pain

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Dentin Bonding Agents
• Used as cavity sealers
• Demonstrated ____ bonding ability to bond restorative material to tooth
• Used to bond ____ and ____ to tooth

multisubstrate
composite resin
amalgam

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Terminology

Liner:
____ layer of material used primarily to provide a barrier to protect the ____ from residual
reactants diffusing out of a ____ and/or oral fluids which may penetrate ____ tooth- restoration interfaces

Liner is added before you ____ the tooth

thin
dentin
restoration
leaky
restore

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Reasons for Use

• Liner
– Seal ____
• Provides ____ barrier to bacteria and their products
– Prevent removal of the ____ by acid
etchants, reducing the potential for increased
dentin ____

If you do composite and put acid on the tooth, it will remove the smear layer and opens up all of the tubules
• we may not want to do this in a ____ restoration
• We can put a liner first and then acid etch so those tubules wont open up

dentin
physical
smear layer
permeability
deep

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• Liner
– Therapeutic effect
• Protect against ____ irritation by restorative materials
• Contribute initial ____ insulation
Ex: you put a deep amalgam next to dentin which is close to the pulp next to a gold crown, and when the amalgam corrodes, 2 dissimilar metals can cause electrical problem
• may not feel pain, but will feel ____
• If you put a ____ under the restoration, it is less likely to be perceived
• Once ____ is over, wont feel anything

Generate some ____ protection
May provide pulpal treatment - Used for ____ and ____ pulp cap

chemical
electrical
weird
liner
corrosion
thermal
direct
indirect

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Reasons for Use
• Liner
– Greatest need with ____ restorations not
well-bonded to tooth

Need this for ____ and ____ crowns (where the tooth is ____ and hasn’t gone under endodontic treatment)

metallic
amalgams
gold
vital

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Clinical Considerations | Applied with minimal thickness (

``` 0.5 dentin pulpal axial lateral ```

``` Materials Liners – ____ – ____ – ____ ```

Calcium Hydroxide Zinc Oxide Eugenol Glass Ionomer

Calcium Hydroxide • Traditionally the most ____ • Thought to stimulate formation of ____ dentin – NO CONCLUSIVE EVIDENCE, UNLESS ____ PULPAL CONTACT Cox CF et al., 1992 • Frequently ____beneath restorations (major ____)** (high ____) • Usually ____ component (paste/paste)

``` popular irregular secondary direct dissolve disadvantage solubility 2 ```

Calcium Hydroxide • pH ____ , very biocompatible, non-____, used ____ to pulp • Some ____ protection (0.5mm) • Compressive strength: very ____ • Modulus of elasticity – ____ • not ____, poor support, flex under ____ forces BIG PROBLEM with this is the very low ____ strength and low ____ of elasticity • cant rely on it to provide support on ____ of amalgam

``` 11-13 toxic directly thermal low low stiff masticatory compressive modulus top ```

Zinc Oxide Eugenol • Believed to have ____ effect on pulp • Inhibits ____ of composite resins ZOE provides the dental office ____ Disadvantage: not compatible with all of the composite systems we use • can use for ____ • If doing a composite or on lay, don’t want to use ____

``` sedative polymerization smell amalgams eugenol ```

Zinc Oxide Eugenol - Pulpal effects: - ____: it is soothing and blunts the pain - ____ - pH ____ - ____ seal: used after endo to seal very well so no more bacteria can get into tooth - anti-____

``` obtundent bacteriocidal 6.6-8 hermetic inflammatory ```

``` Zinc Oxide Eugenol - Indications – sedative ____ restoration – not used in exposure of ____ pulp - Can cause ____ pulp if put on vital pulp – not used under ____ ``` ZOE can be used as a liner underneath a restoration

temporary vital necrotic composite resin

Glass Ionomer - Preferred for lining ____ • Seal dentin because ____ adhere (weakly) • Bond to ____ • Release ____ ions in low concentrations for extended periods of time • Stronger, less ____, and more ____ resistant than calcium hydroxide More used nowadays • it is more preferred b/c it has more positive properties • It chemically (weakly) bonds to dentin • Comparable to composite resin or amalgam • It takes up and releases fluoride • It sets harder so it has more ____ strength • For pulp ____, we will still use calcium hydroxide and still put a layer of glass ionomer on top b/c it can seal and have better compressive strengths

``` cavities chemically composite resin fluoride soluble acid ``` compressive capping

Glass Ionomer • Pulpal response quite ____ – Possibly due to decreased ____ invasion • ____ release • Initial ____ pH • Chemical bond to tooth structure physically excluding ____ • Shown to decrease ____ when placed under amalgam restorations

``` favorable bacterial fluoride low bacteria microleakage ```

``` Glass Ionomer • ____ • Usually 2-component (____/____) • Many newer materials ____ cured – Have better physical properties (high fracture strength, low ____) – Example: ____, Ketac Bond ``` * it is easy to work with * Glass powder system * Light cured * Low solubility, high fractured strength

``` biocompatible powder liquid light solubility vitrebond ```

Terminology Base: A ____ material (1-2mm) used to provide ____ protection for the pulp and to supplement ____ support for the restoration by distributing local stresses from the restoration across the underlying dentin surface. Think of a base as replacing lost dentin • if the restoration is very deep, you want to build up the area in a crown and bridge • It distributes the stress • Has good ____ strength • If you do an occlusal prep that has a very deep part, you can put medicament like a liner that has very good compressive strength above that so you can have a normal pulpal floor to put the restoration on

thick thermal mechanical compressive

Reasons for Use • Base – Used as ____- replacement materials This is a deep cavity that has been cleaned out • very close to pulp • Put a ____ -> ____ -> then restore tooth

dentin liner base

Reasons for Use – Common ____ that must place base to protect from “thermal shock” – Dentin is ____ thermal insulator • Additional insulation ____ needed – Consider Hydrodynamic Effect of Dentinal Sensitivity • ____ movement determines sensory nerve activation to a much greater extent than dentin thickness

misconception excellent rarely fluid

Reasons for Use Base – Mechanical support provides resistance against disruption of thin dentin over pulp during amalgam condensation or cementation procedures – Allows for less bulk of ____ material (Be careful!) • Research shows increased base thickness ____ fx resistance of restoration You lay down the base and let it set so you don’t compress it onto the thin dentin • so you can condense the amalgam with more ____ w/o irritating the pulp Don’t overdo this • if you put too much base on a tooth so your final restoration isn’t too thin • If amalgam too ____ -> it will fracture

restorative decreased pressure thin

Reasons for Use Ideally, ____ mm of dentin or an equally insulating material should exist to protect the pulp As the cavity preparation extends closer to the pulp, a ____ is used to augment dentin to this thickness range

2 | base

Clinical Considerations • Only place on ____ and ____ walls • Not on ____ walls • Not on ____ walls

pulpal axial gingival lateral

Materials - Bases - ____ - ____ - Type of ZOE - ____ - Can be a liner or a base depending how you mix and place it • as a liner, you flow it on • As a base, you add more powder to make it ____ giving you better compressive strength Glass ionomer ____ materials are stronger and stiffer than liner materials

``` zinc phosphate IRM (intermediate restorative material) glass ionomer thicker base ```

Zinc Phosphate • Used in dentistry for over 100 years • Excellent physical properties and support for overlying restorations (high ____ of elasticity) Used a lot in gold ____, only, ____ • Excellent ____ insulation • Provides ____ form

``` modulus inlays crowns thermal resistance ```

Zinc Phosphate • Very ____ shortly after mixing (pulpal problems?) - Need to mix it properly to minimize the acid • can be used as a ____ or ____ – precautions taken to ensure continued health and vitality • Not used for ____ restorations • Does not ____ bond to dentin • ____ manipulation determines properties

``` acidic base cement temporary chemically operator ```

``` IRM • Modified ZOE Modified ZOE with ____ = IRM • Mix to putty-like consistency • Use as a ____ restoration • Use as ____ under amalgam restorations • Not compatible with ____restorations ``` • If a pt cracked their tooth in war, medic can put something in the tooth that is durable until they can get proper treatment • It is ____, blue, or red colored ◦If there’s decay in the tooth, medic would use ____ IRM so the dentist will know there is decay that needs to be removed ◦If it is ____, dentist will just need to restore the tooth • Use IRM to prevent sensitivity ONLY IN ____, not composite • Has good compressive strength

temporary base composite resin ivory red blue amalgam

``` Glass Ionomer • Excellent physical properties • ____ has higher modulus of elasticity and can support restorations • GC lining cement Can be used in: 1. ____ 2. liner 3. ____ very versatile ``` More and more dentists using it as liners and bases • if you use glass ionomer as a base, it is thicker than ____mm • Bonds to ____

conventional cement base 0.5

Resin-Modified Glass Ionomer • Newest material to be used as a ____ • Supported by clinical research * ____ is added to glass ionomer * Has high compressive strength * Used all the time now * It seals the dentin and tooth * It sets hard enough to be a ____ restoration for over a period of time * It can temporize pt’s tooth until they can go get more definitive dentistry * Stays on better than ____

base permanent IRM

New Class of Base? * Based on ____ chemistry * They set harder * Sets for a long time -> ____ min * Most things are light cured or sets very quickly

calcium hydroxide | 8

The best possible base for any restoration is sound ____

tooth structure

Review Calcium Hydroxide – ____ ONLY ZOE – ____ IRM – ____ Zinc Phosphate – ____ Glass Ionomer –____ or ____ ZOE • you can put ZOE on some ____ parts on the restoration. • CANNOT put the bulk of the restoration on ____ of ZOE • Can be used as a temp restoration to get some relief before you restore the tooth ``` IRM • only ____ • Mixed as a ____ • Has good compressive strength ◦Can put ____ over it ```

``` liner liner/temporary restoration base base liner base ``` deeper top base putty amalgam

Shallow, Ideal Cavity Preparation • ____ mm or more of remaining dentin • No ____ for pulpal protection (other than in terms of chemical protection) • Amalgam – Etch, bonding agent, amalgam bonding agent and restore • Composite resin – Etch, prime, bonding agent, restore

2 | need

``` Moderately Deep Cavity Preparation • ____mm of remaining dentin • Place ____ at sites of “less than ideal” protection • Do not use ____ with composite resin ``` • if one area on the occlusal is deeper, can clean it out with slow speed round burr • The rest of the preparation is ideal so we can put a liner of the rest of the restoration • DO NOT use ZOE liner if we will be putting composite on top of that ◦Use ____

1-2 liner ZOE glass ionomer

Deep Cavity Preparation • Less than ____ mm of remaining dentin, but no ____ exposure - You can see ____ • very close to the exposed pulp • Apply ____ to deep areas Apply ____ and then ____ to deeper areas Goal: prevent the pulp from being irreversibly inflamed • If pulp is almost exposed, ____ liner can be applied in the deepest regions and ____ base can be placed over the calcium hydroxide

``` 1 pulp pulpal blushing base liner base calcium hyroxide glass ionomer ```

Shallow: ____ amalgam can be placed on the tooth or could be bonded or use varnish Moderate: Put ____ or ____ in the deeper areas of the prep. Most of the restoration is sitting on sound dentin, so the restoration has a place to properly seat Deep: You have near exposure to the pulp horn. Put ____ liner -> ____ base on top -> then restore with amalgam

``` simple ZOE calcium hydroxide calcium hydroxide glass ionomer ```

Clinical judgment for use of liners and bases – Amount of remaining ____ – Considerations of ____ materials – Type of ____ material being used

dentin adhesive restorative

Pulp Capping Indirect: Indirect pulp capping is when we know we keep taking the decay out of tooth, and we will have an ____ Direct: direct pulp capping is done when we are getting so close to the pulp cap or even ____ to the pulp (may see bleeding) Indirect: no ____ Direct: ____

exposure exposure pulp exposure pulp exposure

Indirect Pulp Capping • Removal of caries from the floor of a cavity just short of clinically ____ the pulp, followed by the application of a “____” to the remaining deep caries. • Supposed to promote ____ and/or formation of ____ dentin. • May avoid pulp exposure and maintain pulp vitality. ``` This is most useful in ____ pts (6-7 years old) that have a lot caries • their tooth is immature • The roots have not formed • Want to keep pulp vital • Or done if pt cannot afford ____ ```

``` exposing medicament remineralization irregular secondary younger root canal ```

``` Indirect Pulp Capping • Small amount of demineralized ____ is left. Sealing ____ or restoration is left to seal out ____ and byproducts ``` * You leave a small amount of ____ dentin * When you put the caris dye on, the dentin will feel ____, but the indicator will still ____ * It is not soft, mushy decay, but it is hard * If you go any further, you will go into the pulp * Use a liner to seal of bacteria and their byproducts

``` dentin liner bacteria demineralized hard stain ```

Indirect Pulp Cap • From the X-ray (Fig 1), looks like need endo procedure and a crown like the premolar • If you want to keep the pulp vital, need to make sure no abscess and that the tooth is testing normally ◦Cannot have a pt do an indirect pulp cap if they have ____ • will want to ____ test as well to make sure pulp is still vital • In Fig3, caries is taken out and it is really close to pulp b/c can see ____ • In Fig4, use ____ to disinfect it and then put it ____ to protect ◦Or can put Dycal first and then glass ionomer ◦So you are putting a medicament in and then sealing it • In Fig5, use ____ to seal everything • In Fig6,7, you bevel the tooth and put composite in • Then tell pt that you tried to keep pulp vital here, so if they have any pain, they will need to let you know ◦Including tooth ____ or they get an ____ ◦Tell pts what you did b/c in case it hurts, they wont be mad at you ◦Can also tell them you did this but they may need a root canal someday

``` toothache (pulpitis) cold blushing glutaraldehyde glass ionomer resin based glass ionomer discoloration abscess ```

Although there is experimental evidence to support the concept of indirect pulp capping it is not permitted in the ____ clinic but allowed in the ____Dental Clinic. The overall policy is currently under review.

main | pediatric

Direct Pulp Capping • When pulp has been exposed ____ or by ____ • “dressing” a pulp exposure with some material, attempting to cause ____ bridging and to maintain pulp vitality

mechanically fracture dentinal

``` Indications • No history of severe, continuous or spontaneous ____ • Respond ____ to pulp testing • Have no observable ____ pathosis • No lingering ____ sensitivity • Mechanical pulpal exposure ``` We can do direct pulp capping where pt has mechanical pulp exposure and the tooth is still ____ • can do this to ____ pts • They respond normal to pulp testing • No apical pathology • No temp sensitivity • You would do a ____ prep where you see some pulp exposure • These are the scenarios you can consider doing a pulp cap instead of ____ procedure

``` pain normally periapical temperature vital trauma crown endo ```

Considerations • ____ of exposure is not a factor in outcome • Critical factor is the ____ OF THE RESTORATION – Studies have shown that direct pulp caps eventually fail if the restoration allows ____ You will need to seal the restoration • if you don’t, then the bacteria can get in and the pulp cap won’t work

size seal marginal microleakage

Procedure - Place ____ dam - Remove ____ caries first • If bleeding, apply pressure with ____ until stops • Place ____ liner over exposure site and adjacent dentin • Can place ____ base over liner

``` rubber superficial cotton pellet calcium hydroxide glass ionomer ```

Direct Pulp Capping ____ is placed directly on the exposed pulpal tissue and a small amount of surrounding dentin. A sealing ____ and/or ____ is placed. This is an example of an MO • there’s a mechanical exposure -> calcium hydroxide liner is placed -> then restore tooth

liner | restoration

Conclusion • Draw backs of calcium hydroxide can be overcome with ____ – ____ • Light cured calcium hydroxide + glass ionomer clinically proven materials with clinical success – ____ – Good physical properties – Provide ____ release – ____ adhesion to tooth structure Over time we want the ____ to reform and the ____ to recede and sea

``` light-cure dissolution antibacterial fluoride chemical ``` dentin tubule bridge pulp

Definitive Restorations Pulpal health should be monitored for a few months ____ to having a cast restoration or being used as an abutment for fixed or removable prosthesis If uncertain, strongly consider ____ therapy prior to restorative treatment If you do a crown for a pt and they have a temp crown, you want to make sure that they don’t have an endo procedure

prior | endodontic

Long-Term Prognosis - ____ - Prognosis. So not as good as indirect pulp cap - Evaluate pulp vitality ____ and ____ at regular intervals – Many are asymptomatic but show radiographic ____ and/or ____ tracts • Advise of possible future need for ____ therapy Have pt check for ____ of tooth and symptoms of ____

``` uncertain clinically radiographically pathosis sinus endodontic discoloration sweating ```

Research - Direct pulp capping with mineral trioxide aggregate (MTA) If you have a kid, you see a lot of decay • since the decay is huge, we know we’re looking at some kind of exposure • They took the whole decay out and witnessed some bleeding • They stopped the bleeding with ____ • Then they used ____ used for endo in primary teeth patients ◦Same chemistry as ____ ◦____ setting material ◦Then they put a restoration on top ◦We can see apecies open at the root (FigE) ◦5 years later (Fig F)- can see ____ has occurred • MTA is not ____ and stays in the tooth • Definitive restoration needs to be placed with bonded ____ • Can see in (Fig5) that the apecies have closed ◦Tooth has stayed ____ and matured • Next year, tooth will be ____ and an endo treatment will need to be done

``` hypochlorite MTA calcium hydroxide slow dentinal bridging removed composite vital symptomatic ```