THE SEALING ABILITY OF IRM(R) WITH THE ADDITION OF HYDROXYAPATITE AS A RETROGRADE ROOT FILLING

The effect of adding 10% & 20% hydroxyapatite (HAP) on the sealing abi lity of IRM (Intermediate Restorative Material) when used as a retrogr ade root filling was assessed using a confocal optical microscope with a fluorescent dye. This was compared with another reinforced zinc-oxi de eugenol cement (Kalzinol), ethoxybenzoic acid (EBA) cement and amal gam. The root canals of 70 extracted human single-rooted teeth were pr epared and filled with gutta-percha and sealer. All the teeth were api cected, retrograde cavities were prepared, and then divided into group s of 10 teeth each and filled with the test materials. A remaining gro up of 10 teeth were used as controls. The extent of dye penetration ar ound IRM, IRM + 10% and IRM + 20% HAP was not significantly different. There was also no difference in the extent of dye penetration between EBA cement and IRM. However the sealing ability of bath these materia ls was better than Kalzinol and amalgam. All the amalgam retrograde ro ot fillings leaked, exhibiting the poorest sealing ability. Dye penetr ated into the root canals of all the positive controls whereas there w as no dye penetration in the negative controls. The addition of 10% or 20% hydroxyapatite did not adversely affect the good sealing ability of IRM.