salicylates and calcium-phosphate--monobasic--anhydrous

Calcium hydroxide cements can lack long-term stability and achieve sustained release by matrix-controlled diffusion of hydroxyl ions. Tetracalcium phosphate (TTCP) hydrolyzes slowly to form calcium hydroxide and a thin insoluble apatite layer that prevents further reaction. In this study, mechanical amorphization was used to create a setting calcium-hydroxide-releasing cement from TTCP. The effect of high-energy ball milling of TTCP on the mechanical properties of the cement was investigated. X-ray diffraction data were used to determine the phase composition of the set cements. An accelerated in vitro test compared pH of water after prolonged boiling of nanocrystalline TTCP cements and a calcium salicylate material. As milling time increased, cement compressive strength and degree of conversion increased. Hydroxyl ion release from the cement was comparable with that from a calcium salicylate material. This new cement system offers the antimicrobial potential of calcium salicylate materials combined with the long-term stability of insoluble apatite cements.

Topics: Anti-Bacterial Agents; Apatites; Calcium Hydroxide; Calcium Phosphates; Compressive Strength; Crystallography; Dental Cements; Hardness; Humans; Hydrogen-Ion Concentration; Hydroxides; Materials Testing; Nanotechnology; Salicylates; Solubility; Stress, Mechanical; Surface Properties; Time Factors; Water; X-Ray Diffraction

An in vitro dye leakage study was performed to compare the apical leakage of a fill with injectable calcium phosphate cement (CPC) filler/sealer and a master silver cone with leakage from a fill of Sealapex sealer and laterally condensed gutta-percha. Ten instrumented, extracted, single-rooted human teeth were obturated with either laterally condensed gutta-percha and Sealapex as the sealer or with a single master cone and the CPC paste sealer. Additional teeth were included in the study to serve as controls. The teeth were placed in 1% poly-R dye solution (pH 7.0) for 5 days. After the teeth were longitudinally sectioned apical leakage of dye was measured. There were no significant differences between the CPC and Sealapex groups. The single cone CPC procedure provided an adequate apical seal against dye penetration. Should retreatment become necessary the single cone may be removed to provide access for instrumentation.

Topics: Calcium Hydroxide; Calcium Phosphates; Coloring Agents; Dental Cements; Dental Leakage; Gutta-Percha; Humans; Root Canal Filling Materials; Root Canal Obturation; Salicylates; Silver