CEMENTATION Flashcards
classifications of cements
liners and bases
temp cements
permanent cements
liners and bases
GIC eg fuju 9 RM GIC eg fuji 2 - bulk fill - command set with light cure - strong adhesive bonds with dentine bonding agents
what can loss of a tempo lead to
- pain
- overeruption and loss of space
- drifting of proximal teeth
- damage to core preparations
temporary cementation functions
1) provide a seal
2) prevent marginal leakage
3) prevent pulpal irritation
4) low strength to allow easy removal
5) protect preparation
ideal properties of temp cement
- 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)
temporary cementation materials
fine particle ZnO E
non eugenol cements eg temp bond
cant use GIC ect too high strength
ad and dis of ZoE
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
purpose of cement
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
ideal permanent cement properties
- 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
permanent cement materials
RM GIC
total etch adhesive resin cements
self etching resin cements
RM GIC
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!
what is RM GIC made from
acid souble glass
polyacid polymers
polymerizing dimethacrylates
- polymerizing reaction
acid base reaction
advanatges of RM GIC
- 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
dis of RM GIC
- 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
total etch adhesive resin cements
etch and bonding agent
ceramic surface etched with HF acid
resin cement with sialine applied to crown
forms micromechnaical bond
NEED good isolation
what is total etch adhesive restorations composed of
resin matrix of bis GMA and inorganic particles filler
either self light or dual cured
advantages of total etch adhesive resin cements
- 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
disadvanyages of total etch adhesive resin cements
- 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
self cured resin cemetns
chemical reaction of 2 materials
common in maryland wings on adhesive bridges,
metal inlays, endo posts
where light does not penetrate
light cure resin cements
light must reach cement for photo initiators
good for aesthetic restorations, different colour shades
dual core resin cements
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
self etching resin cements
easy to use
no pre treatment
can be used for metallic or ceramic or PFM
bond strengths of the resins
self etching less than resin with total etch
cement of choice for each indirect
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
