Definition: A reinforced eugenolate cement in which zinc oxide is combined with a liquid containing ortho-ethoxybenzoic acid (EBA) and eugenol, plus reinforcing fillers (e.g. quartz, hydrogenated rosin). The resulting zinc chelate matrix is stronger and less soluble than standard zinc oxide-eugenol.
Clinical Case
A 45-year-old patient requires a cast metal onlay on a heavily restored lower molar. There is concern about pulpal status, and you want a cement that offers good pulpal tolerance but with higher strength and lower solubility than conventional zinc oxide-eugenol (ZOE). You choose an EBA cement as the luting agent.
Uses
Cavity bases under amalgam where improved strength over ZOE is desired.
Luting cement for cast restorations in situations where a pulp-friendly but mechanically stronger cement is preferred.
How to use them in clinical practice?
Assess indication
Need for a eugenolate-type cement with higher strength and lower solubility than ZOE.
Prepare tooth and restoration
As for other cements: clean, dry but not desiccated.
Dispense and mix
Dispense powder (ZnO + fillers) and liquid (EBA + eugenol) as per manufacturer.
Mix to a thick, creamy or putty-like consistency depending on whether it will be used as a base or a lute.
Higher powder loading is achievable than with ZOE due to fillers.
Place
As base: place on cavity floor and adapt.
As luting agent: load internal surface of restoration and seat.
Set and finish
Allow to set in the tooth under normal oral conditions.
Remove excess, adjust occlusion, polish as needed.
Constituents
Powder
Zinc oxide (~60%)
Inert fillers (quartz ~35%, hydrogenated rosin ~5%) for reinforcement
Liquid
Ortho-ethoxybenzoic acid (EBA)
Eugenol
Typically EBA:eugenol ratio ~2:1 (varies by product)
Chemistry
Both EBA and eugenol contain ortho-substituted aromatic groups capable of chelating zinc ions.
On mixing, zinc ions form chelate complexes with these ligands, producing a robust zinc eugenolate/EBA matrix.
Reinforcing fillers help distribute stress and improve mechanical performance.