Dent Material Cement, Bases, Liner

Cements

Most frequently used

Many applications

Not universal → material specific but all used across dent

Dent assistant role: Manipulate the cement to proper consistency w/in mixing time

Definition time

Regular Cement: any agent that binds to surface to form a hard, brittle, material

Dent Cement: Substance placed in the mouth as a viscous liquid + set to a hard mass

Luting agent: Material that cements two components together like Indirect restoration, orthodontic, bracket, pins, and post.

Luting agents are all cement but not all cement are luting

Acid/Base reactiong

Most cement reaction are acid/Base( except resin)

Either:

Power + Liquid = cement

Paste + paster = Cement

Catalyst + base = Cement

ADA + ISO CLassification

American Dent Association + International standard Org

Type I: luting agent → cement restoration

Type II: Temporary or interim restoration ( except glass ionomer((permeant))

Type III: basses/liner

Protection/Sedation

Protection from pulpal irritants

Bacterial

Mechanical ( trauma from cutting the tooth)

Chemical irritants

thermal conductivity ( occurs when metal restoration is close to tooth)

Dentin too thin to withstand occlusal forcesC

Cavity Varnish ( not cement)

Solution of natural resin (Copal) + Solvent ( alcohol or Chloroform)

Most commonly used is Copalite

High evaporation → must be cap

2-3 layer is needed

Do not pool

Seals dentin tubules protection from irritants

decrease microleakage between tooth + restoration

Cavity Varnish Application

Small amount on cotton pallet + place thin layer on cavity prep → dry for 5-15 seconds or use w/ air syringe → repeat 2-3 layers

Type III cements - Bases + Liners

Liner- Thin layer of protective material over dentin to seal tubules( small hollow structure in dentin that runs towards nerve) from chemical/bacterial irritants

Dycal

Most commonly used liner - Calcium hydroxide + ZN Oxide

Application - Use as liner when dentin is thin over pulp → stimulate secondary dentin growth

Bases

Greater bulk to restore part of missing tooth

Thermal insulator

stronger in part to thickness → support final filling

May irritate pulp

( Pulp → Dentin → liner → Base → finial restoration (amalgam/composite)

Liner Vs Base

Liner:

• Protect pulp from irritation

• Weaker, thinner, no thermal isolation

• cannot support finial restoration

• may stimulate 2ndary dentin grown (dycal)

Base:

• Irritant to pulp

• thermal base, stronger and thicker

  • support to final restorative material

Exceptions

Glass Ionomer liner are very stronger and can be used as base to support finial restoration

Cement cannot be used as finial restoration (unless glass ionomer)

Commonly used in Class V preparation( shaping cavity on gingival third)

very versatile

Type I Cement

Luting agents

Ideal properties:

Adhesion to tooth surface, restorative material

Strength to resist functional force

Not soluble in oral fluids + achieve low film thickness

biocompatible + anticariogenic properties

Radiopacity, ease to manipulation

esthetic and color stability

Adhesion

Bonding of dissimilar material by the attractive force of atoms + molecules

2 Types:

Mechanical- based on the interlocking of one material to another (Velcro)

Chemical- molecular level, 2 diff material swap electrons or share electrons

Adhesion of luting agents

Must be able to adhere to tooth as well to the restorative material being used

Luting agents

Must able to resist forces of mastication + not fracture.

Good compressive strength but limited tensile, shearing, torsion, + flexure

Most demanding clinical requirement

Must have:

Set in mouth, Liquid → hard rock in min, Biocompatible. highly insoluble, must fit precisely (.01)

Luting agent Vs Base/liner

Luting agent needs to be more insoluble than Base and liner

Because Base liner are more soluble ( to acid) they must be covered by final restorative materials.

A luting agents can be exposed to the oral cavity at restoration marginsA

Anticariogenic Properties

Desirable if luting agent can help prevent cavity

Many luting agent release fluoride`

Luting agents classified by composition

Water-base - Zn phosphate + polycarboxylate, GI, Resin-Mod GI

Resin-based- Resin based, esthetic. self- adhesive, provision

Oil-based- ZN oxide eugenol (Zoe)

Zinc Phosphate

Advantage - Low film thickness, Inexpensive, High rigidity, Thermally insulate

Acid/base not all acid neutralized:

Phosphoric acid( liquid) + H2O + Zinc oxide (powder) = Zinc phosphate

exothermic → need cold glass to mix

Disadvantages: Pulpal irrational, Mechanical bond only, technique sensitive, compared to other it has lower strong + more soluble

Not used as much

Zinc Polycarboxylate

Known as Polycarboxylate cement

Zn oxide powder + polyacrylic acid

Bond to tooth structure ( little microleakage)

biocompatible, little pulp irrational

Not very strong, more soluble (GI is the same but better)

Commonly used is duralon

GIC or Glass ionmer cement

Glass powder + Polyacrylic acid

Polyacrylic acid attack the glass to release fluoride (FI) ions

Fun fact:

Bacteriostatic , anticariogenic, re-mineralize tooth structure , can be recharged

It release FI but if patient uses OTC fluoride product or FI Products form dent office, it can re incorporate into the GI for future release

Advantage:

Strong, relatively insoluble, adhesive, biocompatible, fast set time

Resin-modified GI

GI + resin (composite)

2 setting reaction":

Acid/base - reaction occurs on its own

Resin polymerization: can cure on its own but the polymerization reaction need extra help ( light cure)

Advantages:

High tensile + compressive strength, FI release, insoluble, Chemical adhesion to tooth, little sensitivity, think film thickness

Resin- based luting agent

Similar to composite filling material but has lower viscosity to have proper working factor

Uses: Adhering ortho bracket, ceramic crown, Traditional crown and bridges, ceramic inlay/onlays( must be cemented w/ resin-base agent or it will fracture)

Advantage: Very low solubility, high bond strength. self cure, light cure, or dual cure, great with non-retentive crowns or occlusal forces

Compomer

Subset of resins

Resin → compomer ← GI

Oil-based Luting agent

Zn oxide eugenol ( ZOE) O- oil

Zn oxide (powder) + eugenol

Uses: temporary → low strength

• Provisional cementation, temporary restoration, Bases, root canal sealer, periodontal dressing

What to know:

ZOE cannot be used under composite restoration, don’t use on provisional crown if the permanent crown is to be cemented, not lot of Non-eugenol zinc oxide available

Eugenol

Brownish liquid

oil of clove

obtundent agent that sedates the pulp

irritant to oral mucosa + pulp if direct contact

antibacterial

good marginal seal

Neutral phR

Root canal sealers

Endodontic sealer are made of Zn oxide eugenol

Surgical packs

Periodontal dressing

Use post surgery + made of non-eugenol zinc oxide ( can’t use eugenol as it a major irritant)

• Provide support

• comfort during healing

• bleeding control