Lecture 11: Cements

Question 1

what do dental cements do?

Answer 1

create a connective layer to adhere to the two surfaces

Question 2

what are the classifications of dental cements?

Answer 2

• type I: luting agents, permanent and temporary
• type II: restorative materials (fillings)
• type III: liners (pulp capping) or bases (protection) placed within cavity

Question 3

when are permanent cements used?

Answer 3

long term cementation of inlays, crowns, bridges, laminate veneers, orthodontic fixed appliances

Question 4

what are temporary cements used for?

Answer 4

provisional coverage to protect the tooth until the permanent restoration is ready to be cemented

Question 5

what are resin-based cements?

Answer 5

low viscosity versions of restorative composites

Question 6

what is a one paste system and a two paste system for resin-based cements? and how are they cured?

Answer 6

• one base: methylacrylate monomers, initator
• two base:
  *base paste; methylacrylate monomers, initiator
  *catalyst paste: methylacrylate monomers, initiator, activator
• curing: light (less common) or chemical reactions

Question 7

what are temporary resin cements used for ?

Answer 7

• eliminate the problem of potential contamination of teeth by eugenol and other oil based cements when bonding agents and resin cements

Question 8

temporary resin cements have _______, meaning they are easy to remove

Answer 8

low bond strength

Question 9

the commercial example of a resin based cement, 3M - ESPE RelyX Veneer cement, has what composition?

Answer 9

resin: BISGMA and TEGDMA
fillers: zirconia/silica and fumed silica

Question 10

bases are generally _____ than cements and provide ______ for the pulp

Answer 10

stronger, thermal protection

Question 11

low strength bases function as what?

Answer 11

barrier to irritating chemicals

also called liners

Question 12

glass ionomer cements (GIC) are what type?

Answer 12

water based

Question 13

what can glass ionomer cements be used for?

Answer 13

• as restorative: class III and V, intermediate restorations
• as luting: luting cements, adhesives for orthodontics
• as base: pit and fissure sealants, core build up materials

Question 14

what is the composition of glass ionomer cements and what is the reaction?

Answer 14

• liquid: polymeric-water soluble acid
• powder: glasses
• water
• reaction: formation of a cross linked gel matrix that surrounds the partially reacted powder particles

Question 15

what happens during the setting reaction of glass ionomer cements?

Answer 15

• acids starts to dissolve the glass (powder) releasing calcium, aluminum, sodium and fluorine ions
• polyacrylic acid chains are then cross linked by Ca2+
• fluorine ions are dispersed in the matrix

Question 16

what does the addition of tartaric acid do to GICs?

Answer 16

decreases viscosity, increases work time and shortens setting time

Question 17

what is the glass (powder) composition?

Answer 17

silica, calcium, alumina and fluoride

Question 18

what do fillers control in the glass (powder) composition?

Answer 18

• the release of ions
• the setting characteristics
• solubility
• release of fluoride

Question 19

glass ionomers chemically can bond to tooth structure by ?

Answer 19

chelation of the carboxyl groups of the polycarboxylate acids

Question 20

glass ionomer cements have relatively _____ mechanical response and the retention of them is primarily _____ but some _____ occurs

Answer 20

low, micromechanical, chemical bonding

Question 21

GIC are considered superior to many types of cements because ?

Answer 21

they are adherent and translucent

Question 22

what do GICs release for an anti-carcinogenic effect?

Answer 22

fluoride which inhibits demineralization

Question 23

resin modified glass ionomer cements are what????

Answer 23

water based

Question 24

what are resin modified glass ionomer cements used for?

Answer 24

water soluble methacrylate-based monomer that used to replace part of the liquid component of conventional GIC

Question 25

what is the composition and reaction of RMGIs?

Answer 25

-powder: fluoroaluminosilicate glass and a microencapsulated catalyst system
- liquid: polycarboxylic acid modified with methacrylate, HEMA, tartaric acid
curing: acid-base glass ionomer reaction using chemicals, lights or both

Question 26

zinc oxide eugenol is ?

Answer 26

oil based

Question 27

what are some characteristics of zinc oxide eugenol?

Answer 27

• sedative effects on the pulp
• cementation on prepared teeth with dental tubules
• commonly used for luting and intermediate restorations
• short term cementation
• weak and easily cleaned from casting

Question 28

what is the composition and reaction of type I zinc oxide cement?

Answer 28

powder: oxide, rosin and zinc acetate (accelerator)
liquid: eugenol
reaction: catalyzed by water, forms an amorphous chelate of zinc eugenolate

Question 29

what is the composition of type II zinc oxide cement (polymer reinforced)?

Answer 29

• powder: zinc oxide and acrylic resin
• liquid: eugenol

Question 30

what is the composition of type II zinc oxide cement (EBA reinforced)?

Answer 30

• powder: zinc oxide and alumina
• liquid: eugenol
  **forms a stronger crystalline matrix

Question 31

what are the cements used at KSoD?

Answer 31

-adhesive resin cement
- RMGI
- ZOE
- Resin-based
- luting