title: Water loss at normal enamel histological points during air drying at room temperature.
abstract: 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 (Teq ) ranged from 0.5 to 11 h with a mean 0.26 (±0.12)% weight loss. In some samples (n = 5; 15 points), Teq increased as a function of the distance from the enamel surface, and drying occurred at an apparent diffusion rate of 3.47 × 10⁻⁸ cm² 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 cm² 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.
authors.affiliation: Master Program in Dentistry, Health Sciences Center, Federal University of Paraiba, Cidade Universitária, João Pessoa, Paraiba, Brazil.
authors.forename: R C G
authors.initials: RC
authors.lastname: De Medeiros
authors.forename: T A S
authors.initials: TA
authors.lastname: De Lima
authors.forename: C R
authors.initials: CR
authors.lastname: Gouveia
authors.forename: F B
authors.initials: FB
authors.lastname: De Sousa
mesh_terms: D000388:Air; D003743:Dental Enamel / Q000737:chemistry*; D003890:Desiccation; D006801:Humans; D006813:Humidity; D008963:Molar / Q000737:chemistry; D013696:Temperature; D014867:Water / Q000032:analysis*
chemical_list: D014867:Water