Author/Editor		Petelin, M; Skalerič, U; Cevc, P; Schara, M
Title		The permeability of human cementum in vitro measured by electron paramagnetic resonance
Type		članek
Source		Arch Oral Biol
Vol. and No.		Letnik 44, št. 3
Publication year		1999
Volume		str. 259-67
Language		eng
Abstract		The structure and permeability of cementum are changed during the course of periodontal disease. In this study, the transport of water-soluble, spin-labelled molecules through cementum was studied by electron paramagnetic resonance (EPR). Cementum samples cut from different parts of the root were classified into four different groups: (A) samples exposed to the oral environment, (B) samples exposed to the periodontal-pocket environment; (C) samples cut from periodontally involved teeth but not exposed to saliva or periodontal pocket and (D) samples from sound young teeth extracted for orthodontic reasons. In order to obtain undamaged cementum, a dentine layer was left on each sample. Two methods were used to measure the diflfusion coefftcients of spin-labelled molecules in cementum-dentine samples. First, the method of one-dimensional EPR imaging (EPRI) was used to evaluate the penetration of spin-labelled molecules into the cementum/dentine structure. Second, the diaphragm-cell method was used to determine the diffusion coeffcients of the labelled molecules through the cementum under steady-state conditions. The results indicate that the interface between cementum and dentine is a barrier to diffusion. A set of diffusion (D) and partition (K) coefficients to describe the molecular transport in cementum, barrier and dentine was generated from the experimental data of both methods. For cementum (c), the barrier (b) and dentine (d) these coeflficients were: Dc =10 -8 cm2/s, Db =10 -10 o cm2/s, Dd =10 -6 cm2/s and K = 0.1. For the particular periodontally involved and uninvolved teeth the value of the rate-limiting barrier was DbA = 0.3 +- 0.03 x 10 -10 cm2/s, Db B = 1 +- 0.3 x 10 -10 cm2/s, DbC = 0.3 +- 0.03 x 10 -10 cm2/s, DbD = 0.4 +- 0.05 x 10 -10 cm2/s. (Abstract truncated at 2000 characters)
Descriptors		DENTAL CEMENTUM PERIODONTAL POCKET ELECTRON SPIN RESONANCE SPECTROSCOPY PERMEABILITY SPIN LABELS AGE FACTORS DIFFUSION DIFFUSION CHAMBERS, CULTURE