Bases, Liners, and Ideal Class II Preps Flashcards Preview

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Flashcards in Bases, Liners, and Ideal Class II Preps Deck (60)
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1
Q

What are the four criteria that are established during the initial stage of cavity design?

A
  1. outline form and initial depth
  2. resistance form
  3. retention form
  4. convenience form
2
Q

What is done during the final stage of cavity prep design?

A
  1. removal of remaining pits, fissure, infected dentin, and old restorative material
  2. protecting the pulp
  3. secondary retention/resistance form
  4. finishing enamel walls to remove unsupported rods
  5. cleaning, inspecting, conditioning
3
Q

What is the initial depth of a cavity design?

A

0.2-0.8 mm pulpally from the DEJ (into dentin)….usually 0.5mm

4
Q

_______ is the shape and placement of cavity walls that best enables both the restoration and the tooth to withstand masticatory forces delivered along the long axis of the tooth.

A

Resistance Form

5
Q

________ is the shape or form of the prepared cavity that resists displacement or removal of the restoration from tipping or lifting forces.

A

Retention Form

6
Q

_________ is the shape or form of the cavity that provides for adequate observation, accessibility, and ease of operation.

A

Convenience Form

7
Q

What are the four functions of the dentin-pulp complex?

A
  1. Formative (primary/secondary dentin)
  2. Defensive (reparative dentin via odontoblasts)
  3. Nutritive (supply of vital cells)
  4. Sensory (protective/pain response)
8
Q

What is the single sensory response of the dentin-pulp complex?

A

PAIN

9
Q

The Hydrodynamic Theory suggests that pain responses are due to ____________.

A

micro-movements of tubule fluids

10
Q

What type of changes could cause movement of tubule fluids?

A
  • osmolarity changes
  • thermal changes
  • desiccation
  • pressure changes
  • high-speed cutting
11
Q

What are the three possible diagnoses of the pulp status?

A
  1. Normal/Healthy
  2. Pulpitis
  3. Necrotic
12
Q

Reversible pulpitis shows a sensitivity to ______.

Irreversible pulpitis shows a sensitivity to _______.

A

Reversible: COLD
Irreversible: HOT

13
Q

Tooth pain can be evaluated based on these five characteristics:

A
  1. Location
  2. Intensity (sharp or dull; pulp pain is sharp)
  3. Cause of onset (hot, cold, sweet stimulus or spontan)
  4. Duration (lingers or short)
  5. Pain during occlusion
14
Q

Name three clinical methods for testing pulp status.

A
  1. Cold Test /Hot Test
  2. Electric Pulp Test (EPT)
  3. Percussion Test
15
Q

Why do we need bases and liners?

A

to protect the pulp and minimize post-op sensitivity

many materials do not act kindly to the pulp, ex. acid

16
Q

How do bases and liners minimize post-op sensitivity or protect the pulp?

A
  • thermal barrier
  • chemical barrier
  • electrical barrier
  • mechanical barrier
  • control of inflammation
  • control of fluid movement
17
Q

Why are calcium hydroxide liners often placed into very deep preparations?

A

calcium hydroxide stimulates reparative dentin

18
Q

What is a liner?

A

relatively thin layers of material used to:

  1. provide a barrier to protect dentin from residual reactant diffusion or from oral fluids
  2. electrically insulate
  3. thermally protect
  4. provide pulpal treatment (some formulas)
19
Q
Types of Liners include: 
\_\_\_\_\_\_\_ Liners (copal varnish and adhesives), 
\_\_\_\_\_\_\_ Liners (CaOH/Dycal),  
\_\_\_\_\_\_\_\_ Liners (GI/KetacCem), 
\_\_\_\_\_ Liners (ZOE), and
 \_\_\_\_\_\_\_ (Optibond Solo/Gluma).
A
Solution
Suspension
Cement
Eugenol
Dentin Bonding Systems/Sealers
20
Q

True or False: If the remaining dentin thickness is greater than 2.0mm, two layers of copal varnish can be used under amalgam.

A

True

21
Q

List the three common liners used under amalgam (from thinnest to thickest)

A
Solution Liners (2-5 micrometers)
Suspension Liners (20-25 micrometers)
Cement Liners (200-1000 micrometers)
22
Q

One layer of copal varnish will provide a ____% seal, Two layers of copal varnish will provide a ____% seal.

A

55%

85%

23
Q

True or False: CaOH, RMGI, and ZOE are all types of liners.

A

True

24
Q

What are bases?

A

bases are used to provide thermal protection for the pulp and to supplement mechanical support for the restoration
-they distribute local stresses across the underlying dentin surface

25
Q

How thick are typical cement bases?

A

1 - 2 mm

26
Q

Dental cements that are used as a base are mixed at a _____ powder to liquid ratio to increase the final compressive strength.

A

higher

27
Q

Bases provide _____ protection for the pulp and _____support for restorations.

A

thermal

mechanical

28
Q

If the ideal prep design does not remove all carious tissue, what should you do?

A

-extend access opening laterally until the DEJ is no longer carious, remove any carious dentin

29
Q

The RDT (remaining dentin thickness) after preparing a moderately carious lesion is between 0.5 and 2.0 mm thick. A base and liner are placed for amalgam and composite restorations. How do they differ?

A

Amalgam:
Base replaces the missing dentin
-GI and ZnPO4 base
-Copal Varnish or Adhesive liner

Composite:
Minimal Base theory
-GI/ZOE = base
-Copal Varnish or Adhesive = liner

30
Q

Bases and Liners often differ only by their _______.

A

consistency (Powder to liquid ratio)

31
Q

Why is zinc phosphate more difficult to use as a base?

A

a particular mixing technique must be used

32
Q

True or False: RMGI can act as both a liner and a base.

A

True

33
Q

BOARDS: When mixing CaOH for use as a liner, what is the ratio of powder to liquid?

A

mix equal portions of each

34
Q

BOARDS: When mixing ZOE for use as a liner, the paste-liquid system uses ____ drops of liquid per scoop of powder.

A

2 to 3

35
Q

True or False: Bases replace the dentin and enamel.

A

False, bases replace dentin only…do not allow it to coat the enamel margins

36
Q

Why have GI materials replaced ZnPO4?

A

Advantages of GI:

  • adheres to the tooth structure (dynamic ion process)
  • Fluoride release
  • proven clinical record of retention
  • dimensionally stable
  • biocompatible (much kinder to the pulp)
37
Q

True or False: Glass Ionomer materials increase in strength over the course of 24-72 hours as Aluminum ions replace Calcium

A

True

38
Q

KetacCem is a common type of _____.

A

RMGI

39
Q

Caries are considered “extensive” when they are how close to the pulp?

A

when there is less than 0.5mm remaining dentin thickness

40
Q

When pulp capping, how does the type differ based on pulp exposure or near exposure?

A

Near Exposure = less than 0.5mm RDT
= INDIRECT pulp cap

Pulp Exposure = DIRECT pulp cap

41
Q

The ______ pulp cap is used as a defense by initiating reparative dentin.

A

indirect

42
Q

_____ days after the placement of an indirect pulp cap, the cells will differentiate.

A

15

43
Q

After ___ days there will be microscopic evidence of reparative dentin and after _____ days there will be radiographic evidence.

A

30 days = microscopic

100 days = radiographic

44
Q

How do the indirect and direct pulp cap differ?

A

They both have the 15 day differentiation, 30 day microscopic dentin, 100 day radiographic dentin
-however, the direct pulp cap is less effective and the results are not as good

45
Q

The CaOH Liner combines a CaOH paste with a ______ paste, which causes a _______ reaction.

A

polyphenol

acid-base

46
Q

How are the polyphenol groups in CaOH linked?

A

crosslinked by calcium ions

47
Q

CaOH Liner has _____ solubility.

A

HIGH

10-30% volume is lost in 10 years

48
Q

What is the brand name of CaOH liner?

A

Dycal

49
Q

When ionized in low concentration, CaOH stimulates ______.

A

odontoblast formation/reparative dentin

50
Q

What are five factors that contribute to prognosis related to pulp capping?

A
  1. Size of exposure (smaller exposure = better results)
  2. Tooth symptoms
  3. Hemorrhage control
  4. Field Cleanliness (rubber dam)
  5. Sealing the access
51
Q

When is a “sedative restoration” material used? Give two materials that fall into this category.

A

for questionable pulp status or
emergency treatment with limited time

  1. Reinforced ZOE B&T (base and temporary)
  2. IRM (intermediate restorative material)
52
Q

Oil of clove (in ZOE) acts to ______.

A

dull pain (obtundent)

53
Q

Reinforced ZOE cannot be used under ______.

A

composite

54
Q

Why can’t ZOE be used under composite?

A

inhibits polymerization

causes poor bond strength and microleakage

55
Q

For deep caries (with less than 0.5mm RDT) that is asymptomatic, what should be placed under the amalgam restoration?

A
  1. CaOH (or RMGI)
  2. Base
  3. Copal Varnish
  4. amalgam
56
Q

For deep caries (less than 0.5mm RDT or exposure) that is questionable , what should be placed in the cavity?

A
  1. CaOH

2. Sedative Fill (ZOE)

57
Q

Compare liner/base use prior to amalgam preparations:

  1. Shallow tooth prep
  2. moderate-depth tooth prep
  3. very deep tooth prep
A
  1. Shallow: varnish or sealer applied to walls
  2. Moderate: varnish or sealer on walls, liner of ZOE or CaOH for thermal protection
  3. Deep: varnish or sealer on walls, CaOH liner in deepest portion, then GI base
58
Q

How much RDT would indicate the use of medicament prior to placement of amalgam or composite?

A

less than 0.5mm RDT

you would then need a liner on top, then a sealer

59
Q

How much RDT would indicate the use of a liner prior to placement of amalgam or composite?

A

less than 2mm RDT indicates the use of liners

you would then need a sealer on top

60
Q

Always make sure that there is no basing material on ________.

A

margins!

base is only to be placed in the deeper part of the prep, away from margins