Apatite- mullite glass-ceramics have been developed recently as dental materials. The effect of L1OZ and B2O3 content on the sintering and devitrification behaviour ol glasses in the AI2O3-SiO2-P2O5-CaF2-CaO (apatite-mullite) systen:r along with the properties of the resultant glass-ceramics (GCs) was investigated in this study. Glasses were produced by conventional melt-quenching technique and the GCs were produced through sintering and crystallization of glass powder compacts. The resulting glass ceramics were chatacterised using variety of techniques including Differential Thermal Analysis (DTA), X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The XRD results inclicated the crystallization of the apatite-mullite particles both with and without L|OZ andB2O3 addition. Scanning electron microscopy (SEM) examination of heat treated glasses (glass-ceramics) revealed precipitation of rod shape apatite and nano-size spherical mullite particles.Sintering behaviour of glass powders was studied by measuring the percentage of shrinkage in the heat treated samples. GCs with higher amount of LiO2 and B2O3 demonstrated better sintering behaviour and showed higher density values. The chemical resistances of the sarnples were determined by measuring their water absorbtion behaviour. The results also indicated that the presence of LiO2 and B2O3 had beneficial effect on the sintering and water absorption behaviour of the samples

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