CEMENTATION

Question 1

classifications of cements

Answer 1

liners and bases
temp cements
permanent cements

Question 2

liners and bases

Answer 2

GIC eg fuju 9
RM GIC eg fuji 2
- bulk fill
- command set with light cure
- strong adhesive bonds with dentine bonding agents

Question 3

what can loss of a tempo lead to

Answer 3

• pain
• overeruption and loss of space
• drifting of proximal teeth
• damage to core preparations

Question 4

temporary cementation functions

Answer 4

1) provide a seal
2) prevent marginal leakage
3) prevent pulpal irritation
4) low strength to allow easy removal
5) protect preparation

Question 5

ideal properties of temp cement

Answer 5

• Ability to seal against leakage of oral fluids
• Low solubility
• Biocompatibility
• Chemical compatibility with provisional polymer eg protemp
• Ease of use/ease of removal
• Easy to eliminate excess
• Adequate working and setting times
• Compatibility with definitive luting agent (must not interfere)

Question 6

temporary cementation materials

Answer 6

fine particle ZnO E
non eugenol cements eg temp bond

cant use GIC ect too high strength

Question 7

ad and dis of ZoE

Answer 7

easy removal
acceptable sealing properties
obtundent effect on pulp
ease of use

dis
- free eugenol acts as a plasticizer of resin and reduces surface hardness and strength
- eugenol interferes with bond strength of resin cements
must ensure all cement removed prior to definitive resin cement

Question 8

purpose of cement

Answer 8

interface between cement and restoration
interface between tooth and cement
- fill the microgap between tooth structure and restorative material to assist in the retention of the restoration

Question 9

ideal permanent cement properties

Answer 9

• adequate working time with rapid set
• low film thickness (gives even layer)
• low solubility
• high compressive and tensile strengths
• low viscosity
• adhesion to tooth structure and restorative materials
• biocompatible
• cariostatic
• translucency or opacity when required
• radiopaque

Question 10

permanent cement materials

Answer 10

RM GIC
total etch adhesive resin cements
self etching resin cements

Question 11

RM GIC

Answer 11

insoulble in oral fluids
bonds to inorganic phase of dentine
- not strong adhesion and hygroscopic expansion can lead to fracture of ceramic therefore contra indicated for most ceramics

• USED FOR METALS!

Question 12

what is RM GIC made from

Answer 12

acid souble glass
polyacid polymers
polymerizing dimethacrylates

• polymerizing reaction
  acid base reaction

Question 13

advanatges of RM GIC

Answer 13

• Adequate compressive strength, diametral tensile strength, and flexural strength but is less than resin composites
• Easy manipulation and use
• Low film thickness
• Fluoride release similar GIC
• Polymerization is not sig affected by eugenol
• Minimal post-operative sensitivity.
• Some adhesion to enamel /dentine
• Resistance to marginal leakage and some moisture resistance

Question 14

dis of RM GIC

Answer 14

• Dehydration shrinkage due to the glass-ionomer component
• May create stress fractures at exposed cement tooth-restoration interface
• HEMA is responsible for increased water sorption, subsequent plasticity and hygroscopic expansion contraindicating their use for the cementation of all-ceramic crowns and posts in non-vital teeth as expansion induced fracture occurs
• Cement bulk is very hard and difficult to remove

Question 15

total etch adhesive resin cements

Answer 15

etch and bonding agent
ceramic surface etched with HF acid
resin cement with sialine applied to crown
forms micromechnaical bond

NEED good isolation

Question 16

what is total etch adhesive restorations composed of

Answer 16

resin matrix of bis GMA and inorganic particles filler

either self light or dual cured

Question 17

advantages of total etch adhesive resin cements

Answer 17

• superior compressive and tensile strengths
• insoluble in oral fluids
• adhesive
• micromechanical bonding to prepared enamel, dentine, alloys and glass ceramic surfaces
• available in wide range of shades and translucencies

Question 18

disadvanyages of total etch adhesive resin cements

Answer 18

• highly technique sensitive
• high film thickness
• marginal leakage due to PS shrinkage
• severe pulpal reactions when applied to cut vital dentine
• no fluoride release or uptake
• low modulus of elasticity so cannot support long span prosthesis
• difficulty in removing hardened excess resin cement from inaccessible areas
• use of eugenol based provisional luting agents inhibited the complete polymerisation of resin cement

Question 19

self cured resin cemetns

Answer 19

chemical reaction of 2 materials
common in maryland wings on adhesive bridges,
metal inlays, endo posts
where light does not penetrate

Question 20

light cure resin cements

Answer 20

light must reach cement for photo initiators

good for aesthetic restorations, different colour shades

Question 21

dual core resin cements

Answer 21

cure with or without activation from curing light
- light helps seal the margins
fewer shades so less aesthetic

can be used for any NON Metal restorations where there is question of light penetrating

Question 22

self etching resin cements

Answer 22

easy to use
no pre treatment
can be used for metallic or ceramic or PFM

Question 23

bond strengths of the resins

Answer 23

self etching less than resin with total etch

Question 24

cement of choice for each indirect

Answer 24

RM GIC for metal based
high strength ceramic /zirconia cannot be etched so not bonded, unicem used
glass ceramic restorations are etchable with HF, bonded wth primer bonding and resin cement eg calibra