The first aim of this study is to create a cumulative dose-response curve for acetylcholine in men (low serum estrogen levels) to determine the lowest concentration with which we can induce a maximal vasodilation effect on the human gingiva. Furthermore, the second aim of this study is the characterization of the age-dependent effect of sex hormones on gingival blood flow, as well as of the gender differences by applying this concentration to premenopausal men and women with low and high estrogen levels, as well as to postmenopausal subjects.

Gender differences were observed in studies according to gingival microcirculation between physiological circumstances and during wound healing as well.

For blood flow measurement, Laser Speckle Contrast Imaging is a reliable tool. It has good reproducibility, does not touch the measured surface, is easy to use, and can simultaneously measure on a bigger surface.

Two wells are fabricated on the surface of the right lateral incisor (test site) and the labial surface of the left central incisor (control site). These wells are opened towards the high-permeability gingival sulcus, so the dropped solutions acetylcholine vs. physiological saline can easily penetrate the gingival tissues. After applying the solutions, the blood flow is monitored for 19 minutes.

In the study's second phase, blood sampling is taken before the gingival blood flow measurement.

Inclusion Criteria:

• healthy systemic and periodontal conditions

Exclusion Criteria:

• systemic disease and medication
• periodontal disease
• smoking

women and men