Background: Primary teeth are excellent model to figure out the differences in morphological and histological features of tooth resorption. They may be exfoliated due to physiological resorption of their roots or the coexistent physiological and pathological resorption that are usually observed in the replacement period of dentition.
Aim: The aim of this study was to evaluate the qualitative differences in the appearance of the roots of primary teeth undergoing physiological or coexistent physiological and pathological root resorption.
Material and Methods: Twenty primary teeth were examined, Ten exfoliated teeth with physiological resorption represented Group I and ten extracted teeth with coexistent physiological and pathological resorption represented Group II.
Results: At light microscopic examination, group I showed deep round wave like resorption fossae filled with many odontoclasts, and the pulp showed inflammatory cell infiltration along with areas of dystrophic calcification. The odontoblasts were disorganized or disappear completely. Repair by cementum like tissue deposition was found internally. SEM examination revealed variable sized numerous resorption lacunae with smooth edges that had a circular or polygonal shape. Group II showed irregular resorbed root surface and various size odontoclasts besides thick granulation tissue. The pulp was degenerated, necrotic and contained calcification globules. The odontoblastic layer couldn't be identified. Cementum repair was evident externally but at the internal resorption surface. By SEM, the resorption fossae were smaller and irregular in shape with thinner edges.
Conclusion: There were various morphological differences between physiological and coexistent physiological and pathological resorption of human primary teeth