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Mucosal changes at erupting molars in germfree rats
Author(s) -
Magnusson B.
Publication year - 1969
Publication title -
journal of periodontal research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.31
H-Index - 83
eISSN - 1600-0765
pISSN - 0022-3484
DOI - 10.1111/j.1600-0765.1969.tb01964.x
Subject(s) - molar , connective tissue , oral cavity , biology , pathology , dentistry , anatomy , medicine
An accumulation of inflammatory cells in the tissue adjacent to the newly established dentogingival junction of erupting teeth has been reported by several investigators. In order to elucidate the role played by bacteria in the induction of this presumed defence reaction against irritants from the oral cavity, the first and second molars were studied in seven germfree rats aged 14 to 20 days and in age‐matched control animals. After previous demineralisation and embedding in paraffin the molars on one side were serially sectioned sagittally. Inspection of the molar areas revealed no differences in the stage of eruption between the two groups. Also, the general histologic picture was almost identical in the two groups. Before fusion of the dental and oral epithelia, only the ordinary cells of loose connective tissue were present. As soon as the molar appeared in the oral cavity, both germfree and control animals regularly showed some accumulation of inflammatory cells in the vicinity of the epithelial confluence. The greatest number of cells as well as an absolute dominance of leucocytes was noted at the onset of the reaction. Later, lymphocytes became frequent, but then the total number of inflammatory cells, and the proportion of lymphocytes, was smaller in the germfree animals than in the controls. At this stage the numbers of inflammatory cells also varied considerably in different areas around each molar.