The metabolism of progesterone may play a special role in the gingival physiology. The lower the metabolism the higher its hormonal activity in the tissue. In healthy human gingiva, progesterone is metabolized only partially and is therefore in an active form. In the present study, gingival samples from pregnancy gingivitis (n = 1) and granulomas (n = 4) were studied histologically and biochemically. All samples were homogenized and then incubated with [4-14C]-progesterone and NADPH for 2 h at pH 7.4 and 37 degrees C. The metabolites were separated and characterized with column, solvent and thin-layer chromatographies as well as radioautography and quantified with liquid scintillation counting. The results showed low metabolism of progesterone, indicating active hormonal function as in healthy gingiva. It is suggested that progesterone functions as an immunosuppressant in the gingival tissues of pregnant women, preventing the rapid acute-type of inflammatory reaction against plaque, but allowing an increased chronic-type of tissue reaction, resulting clinically in an exaggerated appearance of inflammation.

Osteogenesis imperfecta (OI) results from various gene mutations leading to defects in type I collagen, which is the major component of both bone and dentin. Yet dentinogenesis imperfecta (DI) is found only in half of the patients with OI. Here we document patients from three families with OI and DI lacking the clinical and radiographic features of DI in permanent teeth. However, light and transmission electron microscopic studies of dentin of deciduous and permanent teeth revealed various changes in the morphology of the dentinal tubules and collagen fibers. In one family, diagnosis of DI preceded that of OI. The grade of severity of dentinal manifestations in patients with OI apparently forms a continuum from normal dentin structure to severe DI, and the marked difficulty in diagnosing mild DI may have led to underestimating its frequency. Furthermore, patients with DI should be carefully examined for the possible presence of OI.

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