Radiopacity of resin-modified glass ionomer liners and bases.
BACKGROUND
Lining and base materials for restorations have traditionally been autopolymerized and include conventional glass ionomer cements. Light-cured resin-modified glass ionomer cements have recently become available, but a lack of information exists regarding their radiopacity.


OBJECTIVE
In this study the radiopacity of glass ionomer cements was assessed with a standard method that related densitometric measurements to an equivalent thickness of aluminum.


METHODS
Radiographs were made of specimens with seven materials commonly used as liners and bases: two reinforced zinc oxide-eugenol cements (Kalzinol and Intermediate Restorative Material, De Trey Dentsply), a zinc phosphate cement (SS White, S.S. White Manufacturing), three resin-modified glass ionomer liners (Vitrebond [3M Dental Products], Fuji Lining LC [GC Dental], and Photac-Bond [ESPE Dental Medizin GmbH]), and a conventional glass ionomer liner/base (Ketac-Bond, ESPE Dental-Medizin GmbH), with dentin as a control. The radiopacity of all materials was compared with dentin.


RESULTS
Kalzinol had the greatest radiopacity of the materials tested. The glass ionomer cements were substantially less radiopaque than other materials. The conventional glass ionomer cement, Ketac-Bond, was more radiopaque than the three resin-modified glass ionomer cements. Of the three resin-modified glass ionomer materials, Vitrebond was the most radiopaque and Fuji Lining LC was the least radiopaque.


CONCLUSIONS
Future resin-modified glass ionomer materials are recommended to be formulated to increase radiopacity for improved clinical detection.
Shah
P M
PM
Department of Conservative Dentistry, United Medical and Dental Schools, Guy's Hospital, London, United Kingdom.
Sidhu
S K
SK
Chong
B S
BS
Ford
T R
TR
D015502:Absorptiometry, Photon; D003287:Contrast Media; D003736:Dental Cavity Lining; D003804:Dentin / Q000000981:diagnostic imaging; D004338:Drug Combinations; D005054:Eugenol; D005557:Formaldehyde; D005899:Glass Ionomer Cements / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D008768:Methylmethacrylates; D011861:Radiography, Dental; D012117:Resins, Synthetic / Q000737:chemistry; D015034:Zinc Oxide; D015035:Zinc Oxide-Eugenol Cement; D015036:Zinc Phosphate Cement
D003287:Contrast Media; D004338:Drug Combinations; D005899:Glass Ionomer Cements; D008768:Methylmethacrylates; C088835:Photac-Bond; D012117:Resins, Synthetic; D015035:Zinc Oxide-Eugenol Cement; C061499:Ketac-Bond; C067790:Vitrabond; C084541:Fuji glass-ionomer lining cement; D005557:Formaldehyde; D005054:Eugenol; C031667:IRM cement; D015036:Zinc Phosphate Cement; C003799:N2 Dental Cement; D015034:Zinc Oxide