glass ionomer cements can be used with metal and metal-ceramic restorations provided they possess adequate retentive and resistance form.6 they are however, contraindicated for all-ceramic restorations that are low-strength. it is also suitable for use in amalgam restorations, due to its ability to withstand amalgam condensation. it has been said that gi cements can give more rigid support compared to calcium hydroxide cements, making it popular as a lining material. glass ionomer has an aesthetic advantage over zinc phosphate and zinc polycarboxylate when it comes to luting porcelain crowns. this is because of the presence of unreacted cores of glass rather than zinc oxide, therefore making it more translucent. however, improvements are still required to achieve a true match to porcelain. glass ionomer has not been recommended for cementing posts, as the vibration caused by tooth preparation may decrease the retention provided by the cement. in orthodontics, glass ionomer cements are widely used to attach orthodontic bands. the presence of an adhesive seal between the cement and tooth structure additional to fluoride release can help to maintain teeth in good condition throughout orthodontic treatment. however, in practice, the high rate of brackets debonding during treatment has shown that glass ionomer is not a suitable material in this aspect. resin modified glass ionomer rmgic has demonstrated a successful history when used for both metal and metal ceramic restorations the cement also demonstrated good results with metal and composite fibre posts. however, they do not provide adequate retention when used on tooth preparations with poor retention and resistance forms. due to the possibility of hygroscopic expansion, these cements are not recommended for use with all-ceramic restorations that are susceptible to etching and with posts. similar to the glass ionomer cement, rmgic can also be used to provide a high retentive strength when used in cementation of metal copings on uremic teeth with retentive preparations. resin resin cements are widely selected for luting non-metallic restorations, resin bonded bridges, ceramic crowns and porcelain veneers. they are available in a different number of shades, viscosities and aesthetic try-in pastes. these cements are also an option for use with ceramic and resin composite inlays and onlays. they also demonstrated a favourable outcome when used for all-ceramic restorations, veneers, metal or metal-ceramic restorations with compromised retention and resistance form. resin cement is also shown to be useful for cementation of post in endodontically treated teeth. self-adhesive cements self-adhesive cements do not require intermediate steps to bond tooth structure, unlike resin cements. this gives simplicity and efficiency in its use. they are dual-cured and are most effective when bonded to dentine. it is suitable for cementing all-ceramic crowns, porcelain inlays and onlays. self-adhesive resin cements has shown an acceptable clinical result when used for ceramic inlays. self-adhesive resin cements also demonstrated high and adequate survival rates when used as a cement for metal ceramic crowns making it a feasible alternative. zinc oxide eugenol zinc oxide eugenol is used for luting temporary restorations due to its good sealing abilities but inferior physical properties. eugenol containing cements should be used with caution as the eugenol can contaminate the preparation by inhibiting the polymerization of certain resin based composites which are used as a definitive filling material. they also reduce the bond strength of both total and self-etching adhesive systems to dentin if used before an indirect bonding restoration. another report shows that there is no difference in bond strengths of self-adhesive resin cements to dentine between prior application of eugenol free and eugenol containing provisional cements. later publications show a reduction in luting agent bond strengths to dentine when eugenol containing provisional cements are used. nevertheless, contamination of dentine which interference with adhesion of definitive luting agent is inevitable when a provisional cement is used regardless of whether the cement contains eugenol or not. selection of luting agent to be used for a given restoration should be based on a basic knowledge of the materials available, the type of restoration to be placed, the requirements of the patient and the expertise and experience of the clinician. summary properties of cements type of luting agents examples constituents properties advantages disadvantages definitive cements zinc phosphate cements fleck's zinc phosphate cement (mizzy, cherry hill, nj, usa) zinc oxide powder + magnesium oxide (2-10%) + phosphoric acid (45-64%) non-adhesive solely mechanical retention acidic reasonable working time high early strength good compressive strength irritant to pulp (low ph) high solubility (very soluble in its non-matured state) low tensile strength (brittle) polycarboxylate cements poly f plus (dentsply) zinc oxide powder + polyacrylic acid (30-40%) pseudoplastic antibacterial properties adhesive to enamel, dentine, some metals higher tensile strength less irritant to pulp (low ph but less penetration to pulp due to high molecular weight adequate resistance to water dissolution short working time low compressive strength not resistant to acid dissolution glass polyalkenoate cements aquacem (dentsply) fluoroaluminosilicate glass + acrylic acid or of a maleic/acrylic acid copolymer +tartaric acid high early solubility coefficient of thermal expansion similar to tooth cariostatic potential (fluoride release) translucent (can be used for porcelain crowns) tooth sensitivity after restoration delivery susceptible to moisture contamination during 1st few hours of placement resin modified glass polyalkenoate cements and compomers relyx luting cement (3m espe) kromoglass 2 (lascod) kromoglass 3 (lascod) glass ionomer + resin monomer improved biocompatibility cariostatic potential (fluoride release) compressive strength, diametral tensile strength and flexural strength improved compared to zinc phosphate/zinc polycarboxylate/glass ionomer but less than composites easy manipulation and use fluoride release as gic reduced solubility as compared to gic high bond strength to moist dentine hygroscopic expansion, so avoid under conventional all ceramic crowns chemically adhesive resin luting cements panavia f (kuraray dental) relyx arc (3m espe) derive from resin composites with the active constituent being either 4-meta (4-methacryloxyethyl trimellitate anhydride) or mdp (10- methacryloyloxydecyldihydrogenphosphate) adhesively bonded to metal-based restorations difficult to retrieve metal-based crowns cemented resin luting cements relyx unicem adhesive luting with ceramic restorations self-adhesive (etch and bond) high compressive tensile strength low solubility good aesthetic properties does not bond chemically to metal difficult excess removal of cement technique sensitive provisional cements zinc oxide eugenol provisional cement tempbond (kerr) two-paste material (eugenol, zinc oxide) setting time reduces with increase with temperature good sealing ability low tensile strength/compressive strength/solubility eugenol interferes with polymerisation of resin composite zinc oxide non-eugenol provisional cement temp-bond ne™ long chain aliphatic acids/aryl-substituted butyric acid, zinc oxide particles satisfactorily seal and retain well-fitting provisional restorations toxic if placed near pulp tissue resin provisional (very little independent research has been conducted) tempbond clear (kerr) sensitemp (sultan, hackensack, nj, usa) temporary resin cement (mizzy, cherry hill, nj, usa)