Vergleichende lichtmikroskopische Untersuchung von gesundem und erkranktem parodontalem Ligament (PDL) des Menschen

Abstract

Inflammatory disease of the periodontium (periodontitis) is characterised by an irreversible loss of tissue that anchored the teeth. In Germany periodontitis has replaced caries as the main reason for the loss of teeth. The present study is focused on the periodontal ligament (PDL) that finally enables the connection to the alveolar bone. As a functional unit the periodontium includes - beside gingiva, cementum and PDL - also the alveolar bone. That is the reason why experimental research on humans is ethically hindered and the main evidence is won by animal research. Nevertheless there are some important histological studies about the human PDL that especially investigate cellulary, structural and extracellular matrix elements, also concerning stem cells. However lots of questions about human PDL could not be answered yet. According to the present state of knowledge a systematic study of human periodontal ligament by comparing healthy and disseased tissue does not exist. So it is the aim of the present paper to win more evidence in research of the human PDL. By using the inflammatory markers HAM-56, CD 11b and anti-neutrophil-elastase the present study showed that principally there are more infammatory cells in the disseased PDL, but actually their quantity was quite less. The characterisation of fibroblasts and cells closed to the cementum showed a higher amount and bigger size of cells in the healthy PDL that is probably caused by aging process. The immunohistochemical detection of coallagen type I, III, IV and XII does not show any difference between heathy and disseased samples. Nonetheless – in contrast to earlier investigations – collagen type III could not be detected in the cementum. According to the present stage of knowledge the verification of collagen type XII in the human PDL was provided for the first time. Apart from the presence of a tendentially higher amout of CD 90-positive endothelial cells, the investigation of the human PDL - by using the adhesion molecules CD 29, 44 and 90 - showed no disparity between heathy and disseased tissue. Still, according to the present state of knowledge, in the present study the detection of CD 29- and CD 90-positive fibroblasts and cells closed to the cementum, as well as CD 29-, CD 44- and CD 90-positive endothelial cells were provided in healthy and disseased human PDL for the first time.