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Water loss at normal enamel histological points during air drying at room temperature
Author(s) -
MEDEIROS R.C.G.,
LIMA T.A.S.,
GOUVEIA C.R.,
SOUSA F.B.
Publication year - 2013
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1111/jmi.12037
Subject(s) - enamel paint , relative humidity , diffusion , humidity , chemistry , mineralogy , materials science , analytical chemistry (journal) , composite material , meteorology , chromatography , thermodynamics , physics
Summary This in vitro study aimed to quantify water loss at histological points in ground sections of normal enamel during air drying at room temperature (25°C) and relative humidity of 50%. From each of 10 ground sections of erupted permanent human normal enamel, three histological points ( n = 30) located at 100, 300 and 500 μm from enamel surface and along a transversal following prisms paths were characterized regarding the mineral, organic and water volumes. Water loss during air drying was from 0 to 48 h. Drying occurred with both falling and constant‐drying rates, and drying stabilization times ( T eq ) ranged from 0.5 to 11 h with a mean 0.26 (±0.12)% weight loss. In some samples ( n = 5; 15 points), T eq increased as a function of the distance from the enamel surface, and drying occurred at an apparent diffusion rate of 3.47 × 10 −8 cm 2 s −1 . Our data provide evidence of air drying resulting in air replacing enamel's loosely bound water in prisms sheaths following a unidirectional water diffusion rate of 3.47 × 10 −8 cm 2 s −1 (from the original enamel surface inward), not necessarily resulting in water evaporating directly into air, with important implications for transport processes and optical and mechanical properties.