Contact Angle Measurements on Human Enamel — An in vitro Study of Influence of Pellicle and Storage Period

In this study, contact angle (Θ) measurements on enamel from four patients were carried out in vitro. The experiments were done with and without the acquired pellicle. The results show that if ΘA, ΘB, and Θ C are the contact angles of enamel with pellicle, enamel 3-7 μm under the anatomical surface, and enamel 100-200 μm under the surface, then ΘA > ΘB > ΘC, respectively. The biological variation in one patient is comparable to the biological spreading among patients; the biological variations are several times greater than are the experimental errors. Storage experiments indicate that enamel surfaces change strongly after extraction if stored in water; main changes occur within one wk.