Causes of Tooth Resorption - Resorption of bone is a normal physiological response to stimuli throughout the body - Root resorption in permanent dentition and sometimes in the primary dentition is pathological - Chronic stimuli damage the protective layers of the root, exposing dentin to osteoclasts - Common causes of root resorption include inflammation from pulp necrosis, trauma, periodontal treatment, orthodontic tooth movement, and tooth whitening - Less common causes include pressure from malpositioned ectopic teeth, cysts, and tumors - Dental trauma - Orthodontic treatment - Endodontic treatment - Periodontal disease - Genetic factors

Pathophysiological Mechanisms of Tooth Resorption - Osteoclasts are responsible for the resorption of the root surface - Receptive activator of nuclear factor kappa-B ligand (RANKL) is a regulator of osteoclast function - Osteoprotegerin (OPG) inhibits RANKL and osteoclast activity - Bacterial presence leads to pulpal or peri-periapical inflammation, causing leukocyte chemotaxis - Damage to the periodontal ligament can lead to RANKL release activating osteoclasts - Activation of osteoclasts - Release of cytokines and prostaglandins - Interaction between RANKL and RANK - Disruption of the balance between resorption and formation - Inflammatory response in the periodontal ligament

Classification of Tooth Resorption - Resorptive lesions are categorised as internal or external - Internal root resorption involves the loss of intraradicular dentin from within the root canal - External root resorption is the loss of tooth structure from the external surface of the tooth - External inflammatory root resorption is caused by trauma or pressure on the root surface - External cervical root resorption affects the cervical area of the tooth, below the epithelial attachment - External root resorption - Internal root resorption - Inflammatory root resorption - Replacement root resorption - Surface resorption

Diagnosis of Tooth Resorption - Clinical examination - Radiographic imaging (e.g., periapical, panoramic, cone beam computed tomography) - Transillumination - Vitality tests - Histopathological examination (in severe cases)

Treatment of Tooth Resorption - Monitoring and observation (for mild cases) - Endodontic therapy - Orthodontic treatment modification - Surgical intervention (e.g., root resection, hemisection) - Restorative procedures (e.g., crown, bridge, implant)