A method of synthesizing hydroxyapatite nanorods, having high purity, high crystallinity and high aspect ratio is disclosed here. In one embodiment, high crystalline hydroxyapatite nanorods with relatively stoichiometric structure are prepared via hydrothermal method at 200.degree. C. and under moderate acidic conditions. The synthesized hydroxyapatite nanorods have a diameter of 30-95 nm, a length of 850-1400 nm with an average aspect ratio of 24, degree of crystallinity of 73% and stoichiometry ratio of 1.69. Further it discloses the use of HAp in dental adhesive. The dental adhesive comprising synthesized HAp shows improved diametral tensile strength and high microshear bond strength. Energy dispersive X-ray mapping confirmed the uniform distribution of nanorods in the adhesive matrix. The synthesized hydroxyapatite nanorods have high colloidal stability in the dental adhesive solution. The nanorods are well dispersed and protected from aggregation by their high surface charges confirmed by zeta potential measurement.