DH220 Dental Materials

Lecture #2

Prof. Lamanna RDH, MS

Restorative Dentistry

Intermediary Materials:Dental Cements, Temporary Restorations

& Periodontal Dressing

The tooth is prepared and an intermediary material is placed.

What is the purpose of placing intermediary materials? Answer

Where are intermediary materials placed? Answer

Next

A. Which of Black’s Classification is this caries?

B. Which of Black’s Classification are these preparations?

1 23

AnswerAnswer

Varnish1. Composition: resin = natural

or synthetic

2. Use: seal dentinal tubules, prevent chemical irritation to the pulp, and migration of metallic ions.

3. Application: 2 thin coats

4. Location: floor & walls in prep.

5. Special characteristics:

- Rapid evaporation due to solvent; during use the cap must be replaced immediately.- Easily abraded, negating functional purpose.- Should not be used with composite or resin restoration; inhibits proper curing.

Liner1. Composition: Ca(OH)2*, ZOE, GI

2. Use: prevent bacterial invasion; chemical irritation; pulp cap - *Ca(OH)2

only.

3. Application: thin layer

4. Floor of prep, dentin only

5. Special characteristics:

Ca(OH)2 – 1. bacteriostatic – inhibits bacterial spread 2. ↑ pH (11) – stimulus for 2° dentinal formation 3. ↑ solubility – used only in the deepest portion

of the cavity prep. – closest to the pulpal horn 4. compatible with ALL restorative materials

Glass Ionomer – 1. releases fluoride for therapeutic advantage (anticariogenic effect) 2. direct (chemical) adhesion to enamel, dentin, and cementum.

3. radiopaque

ZOE – 1. non-irritating to pulp – eugenol has a soothing (obtundent) effect on the pulp.

2. not utilized as a direct pulp cap – eugenol in a high concentration can be toxic to the pulp.

3. not used under composite restor. – interferes with polymerization.

Base1. Composition: ZOE, GI,

ZOP, Zinc Polycarboxylate

2. Use: thermal/elect. insulator, replacement for missing dentin, mechanical support for restoration

3. Application: Thick layer

4. Location: floor of prep,dentin only.

base

5. Special characteristics:

ZOP - 1. Acidic cement – chemical irritant to the pulp – used in conjunction with calcium hydroxide liner in deep cavities (< 1mm dentin remaining) 2. very specific mixing technique:

• mixed by increments (cut into several sections of powder) • allows for exothermic reaction (release of heat)

Zinc Polycarboxylate –

1. direct (chemical) adhesion to enamel, dentin, and cementum. 2. polyacrylic acid – not as irritating to the pulp as phosphoric acid 3. not as strong as ZOP

Varnish, Liner, & Base Application

varnish

base

liner

*if pulpal exposure –Ca(OH)2 onlyas pulp cap

*

Cement1. Composition: ZOE, GI, ZOP,

Zinc Polycarboxylate, andResin cement

2. Use: luting agent

3. Application: runny, loose

4. Location: inside crown, bridge,etc.

5. Special Characteristics:Resin cement:

1. material of choice for luting.

2. requires use of etching agent.

3. mechanical retention to enamel by acid-etch technique

p. 94

Maryland Bridge

1. Facial view of bridge

2. Lingual view – luted with resin cement

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2

pontic

1

Weakest point of a crown is the margin. Always carefully evaluate the margin for washout when dental charting your patients.

Marginal washout

Identify the following intermediary materials: liner, base, or luting agent.

1

2

Answer

3

Composition:ZOE, ZOP, Zinc Polycarboxylate,

GI, and Resin Cement

** Review the typed handout for the composition of these five materials**

Differences between these materials??????

1. Consistency of the mixture – ex: thin, thick

2. Intended use by the clinician – ex: liner, base

3. Powder particle size – ex: small, large

Temporary & Interim RestorationsI. Temporary Restorations –

A. Use: - provisional for short term – days, weeks.

- pulpal healing for determination of treatment (ie: endo.)

- fabrication of lab work.

B. Material: - ZOE – obtundent effect ** not used if composite is placed!!!

- GI, ZOP, etc. WHY??

Answer

II. Interim Restorations –

A. Use: - provisional for long term – months, up to a year.

B. Material:

- preformed crowns – stainless steel or aluminum

- crowns & bridges – acrylic (polymer)

Periodontal dressing

1. Use: patient comfort from possible injury after surgery, undisturbed healing, reduce possibility of 2º bleeding & infection, and acts as a splint.

2. Composition: zinc oxide & non-eugenol paste - most commonly used material.

3. Handling: Lab

4. Placement: Lab

5. Ingredients: any item listed cause concern??

(p. 7 in typed handout)

1. Before surgery

4. After surgery

2. 3. Placement and removal

of dressing

Mixing TechniqueReference Dental Materials Lab

ZOP

Glass ionomer -pull test for luting consistency

ZOP – mixed for a base consistency

Mixing & handling guidelines – see separate handout in your Lab workbook p. 53 - 56.

Just a few -

** Review the handout for special characteristics of each material in Lab workbook (p. 53 + 54).

It’s show time……mixing dental cements.

Visit www.edpuzzle.com to view 8 very short videos on the mixing techniqueof intermediary materials, pulp cap and periodontal dressing.

Mixing Glass Ionomer Mixing ZOP