Study of a hydraulic dicalcium phosphate dihydrate/calcium oxide-based cement for dental applications.
By mixing CaHPO(4) x 2H(2)O (DCPD) and CaO with water or sodium phosphate buffers as liquid phase, a calcium phosphate cement was obtained. Its physical and mechanical properties, such as compressive strength, initial and final setting times, cohesion time, dough time, swelling time, dimensional and thermal behavior, and injectability were investigated by varying different parameters such as liquid to powder (L/P) ratio (0.35-0.7 ml g(-1)), molar calcium to phosphate (Ca/P) ratio (1.67-2.5) and the pH (4, 7, and 9) and the concentration (0-1 M) of the sodium phosphate buffer. The best results were obtained with the pH 7 sodium phosphate buffer at the concentration of 0.75 M. With this liquid phase, physical and mechanical properties depended on the Ca/P and L/P ratios, varying from 3 to 11 MPa (compressive strength), 6 to 10 min (initial setting time), 11 to 15 min (final setting time), 15 to 30 min (swelling time), 7 to 20 min (time of 100% injectability). The dough or working time was over 16 min. This cement expanded during its setting (1.2-5 % according to Ca/P and L/P ratios); this would allow a tight filling. Given the mechanical and rheological properties of this new DCPD/CaO-based cement, its use as root canal sealing material can be considered as classical calcium hydroxide or ZnO/eugenol-based pastes, without or with a gutta-percha point.
Laboratoire de Chimie Générale et Minérale, Faculté de Pharmacie de Montpellier, 15 Avenue Charles Flahault, 34060 Montpellier Cedex 2, France.
Hasna
H
el-Briak
Denis
D
Durand
Josiane
J
Nurit
Sylvie
S
Munier
Bernard
B
Pauvert
Phillipe
P
Boudeville
D017610:Calcium Compounds / Q000737:chemistry; D002130:Calcium Phosphates / Q000737:chemistry; D003738:Dental Cements / Q000737:chemistry*; D006801:Humans; D007267:Injections; D019563:Mechanics; D010087:Oxides / Q000737:chemistry; D012212:Rheology; D012387:Root Canal Filling Materials / Q000737:chemistry; D013696:Temperature; D013997:Time Factors
D017610:Calcium Compounds; D002130:Calcium Phosphates; D003738:Dental Cements; D010087:Oxides; D012387:Root Canal Filling Materials; C485828:alpha-tricalcium phosphate; C485830:tetracalcium phosphate; C485838:calcium phosphate, monobasic, anhydrous; C020243:calcium phosphate; C016538:lime; C485829:calcium phosphate, dibasic, anhydrous