Bacterial invasion of the periodontium in a case of juvenile periodontitis.

A case of juvenile periodontitis is described where biopsy material taken from a lower right incisor during periodontal surgery revealed plaque-derived bacteria present within the periodontal connective tissue. The gingival connective tissue contained an inflammatory infiltrate which exhibited a profound loss of collagen and was dominated by plasma cells, many of which had a bizarre cytoplasmic morphology, The invading bacteria were morphologically heterogeneous but mainly gram-negative. Some were found in a patchy distribution in the apical margins of the inflammatory infiltrate and more numerous groups of organisms were in the collagenous connective tissue apical to the infiltrated area. Polymorphonuclear neutrophils (PMN) were seen in association with the bacteria and some PMN showed phagocytosis of bacteria without significant degranulation. This is the first description of bacterial penetration of the periodontium in juvenile periodontitis; it is not known how frequently this occurs but it is an interesting finding in a condition where there is known impairment of one branch of the host's defence mechanisms, namely pMN phagocytosis and degranulation.