Author/Editor		Hribar, S; Rauter, A; Štrancar, J; Pavlica, Z; Petelin, M
Title		Ureditev hidroksiapatitnih kristalov v dentinu
Translated title		Arrangement of hydroxyapatite crystals in dentine
Type		članek
Source		Zobozdrav Vestn
Vol. and No.		Letnik 64, št. 1
Publication year		2009
Volume		str. 3-8
Language		slo
Abstract		Background: Dentine forms the bulk of the tooth. It is a hard elastic tissue that protects the pulp chamber. Knowledge of the arrangement of hydroxyapatite (HA) crystals is important for understanding the mechanical properties of dentine and the progression of tooth decay. Materials and methods: Dentine samples (1.5 x 3 x 4 mm) and dentine powder were prepared from 10 human upper first incisors extracted because of advanced periodontal disease. The samples and the powder were irradiated with C060 gamma rays at room temperature in the presence of air to a final dose of 5 IJGy. EPR spectra were measured at different orientations relative to the magnetic field. The arrangement of HA crystals and dentinal tubules was studied by comparing the measured spectra with those obtained by a new simulation method.Results: The proportion of aligned HA crystal s in dentine amounted to 5.6 ± 0.7 per cent; other crystals had random orientation. The aligned crystals formed intratubular dentine, their longer axes lay perpendicular to the axes of dentinal tubules. In root dentine, the slope of the tubules, determined with reference to the vertical axis passing through the root centre, amounted to 24.3 o ± 2 degrees. Conclusion: On the basis of data from the literature and our results, we conclude that the arrangement of HA crystals and the collagen fibril network determine the mechanical properties of dentine and the progression of tooth decay.
Descriptors		DENTIN HYDROXYAPATITES CRYSTALLIZATION ELECTRON SPIN RESONANCE SPECTROSCOPY