RESORPTION IN THE PRIMARY DENTITION: WHEN IS RESORPTION A NORMAL PHYSIOLOGICAL DEVELOPMENTAL PROCESS AND WHEN IS IT A PATHOLOGICAL PROCESS?
In this overview, physiological resorption of the primary dentition in connection with the normal development of the permanent dentition is described. In focus is also the phenotypic pattern of pathological resorption. Pathological resorption can be either unexpected aggressive resorption, a aggressive resorption with a known aetiology, or lack of resorption. Four different forms of unexpected aggressive resorption are described, and a single example of aggressive resorption following trauma (known aetiology) is given. Lack of resorption is seen in cases, where the primary teeth do not resorb. This is described in three examples. The aetiology behind normal physiological resorption and the pathological deviations from the normal pattern of resorption are seemingly unknown. The aetiology behind resorptions needs to be elucidated in the future.
In the article, the aetiology of resorption and the long-term consequences of pathological resorption in both the primary and permanent dentition are discussed. The aetiological aspect is clarified based on radiographic studies and recent immunohistochemical studies of the periodontal membrane of human teeth. The layers in the periodontal membrane close to the root surface in primary teeth are the same as the layers in the permanent teeth. Therefore, the primary teeth are focused upon in the research model for the resorption process in human tooth tissue.