To determine whether the inflammation afflicting the sinus mucosa shortly after oroantral communication is due to an injury or an infection, microbiological studies of two biopsy preparations each were performed simultaneously in 20 patients with the diagnosis: radix in antro. As a rule, notwithstanding the time of oroantral communication aerobe micro-organisms corresponding to the local conditions of oral and nasal flora. Primary asepsis of the sinus mucosa being assumed, an infection of the sinus maxillary has to be taken into account only one hour after the dislocation of a root of the tooth into the sinus maxillary. After six hours the infection will be followed by an inflammatory reaction.

For further elucidation of the connection between tumor differentiation, intensity of stroma reaction and the capacity of prostacyclin biosynthesis comparable investigations were performed on the PGI2 formation and the microscopic pattern of 10 tissue samples from naevus cell tumors, skin basalioma, oral pavement epithelium carcinoma and their direct adjoining region. The effects were compared with 10 tissues from healthy oral mucosa and facial skin. The results indicate that the PGI2 activity depends on the quantity of cells within the tissue. The various cells were stimulated in a different manner. The highest values of the PGI2 biosynthesis were found in cells of an inflammatory proliferation direct adjoining the oral pavement epithelium carcinoma. This shows a connection between tumor differentiation, intensity of stroma reaction and the activity of prostacyclin biosynthesis, possibly indicating a criterion of malignity for the prognosis of the tumor disease.