Root Resorption

Root Resorption

1. Process

   • Resorption by Giant cells (mononuclear phagocytes)
   • Resorption of tooth prevented by Pre-dentine & Pre-cementum layer (not fully mineralised)
   • Resorption occurs when fully mineralised dentine or cementum is present against soft tissue
     • Damage to pre-dentine/pre-cementum layer
     • Death of Odonto/Cementoblasts -> layer becomes fully mineralised)
   • Consistent stimulation required for continued resorption
     • Otherwise resorption stops after 2-3wks & surface repaired with cementum-like material (not fully mineralised)
       • = Transient root resorption
         • No clinical significance
         • Normal wear & tear
         • Not detectable

2. Inflammatory resorption

   • Giant cell stimuli = Inflammation
     • Systemic disorder
     • Pressure
     • Infection
   • External resorption
     • Cervical
       • Aggressive form
       • Less common
       • 1) Minor trauma -> damage below attached junctional epithelium
         • 2) Pre-cementum lost
           • 3a) Junctional epithelim grows down & protects root from giant cell colonisation
           • 3b) Giant cells colonise root
             • 4a) Transient root resorption
             • 4b) Stimulus -> progressive resorption
               • Pulp space infection
                 • Non-vital pulp
                   • Raise flap, clean defect & repair (GIC/composite)
                   • RCT
               • Plaque build up -> external infection
                 • Vital pulp
                   • Pre-dentine prevents pulpal invasion
                   • Treatment
                     • Improve OH
                     • Raise flap, clean defect & repair (GIC/composite)
               • Bleaching agents
       • Diagnosis
         • Localised gingival swelling/bleeding
         • Pulpitis/PAP signs
         • Pink spot on tooth
         • Radiograph
     • Non-cervical
       • Stimulus
         • Pressure
           • Orthodontic treatment
           • Ectopic/unerupted tooth
             • U3s causing resorption of U2s
         • Infection
           • Apical periodontitis (chronic)
           • Canal contents stimulate giant cells
           • Treatment = RCT
             • Dress with CaOH for 1wk before obturation
           • Initial insult often = Trauma
         • Systemic disorders
           • Hyperparathyroidism
           • Paget's disease
           • Tumours
     • Bone & root resorption
       • Radiographically
         • Radiolucency moves in relation with different radiograph views
         • Tramlines of pulp chamber visible over radiolucency
   • Internal resorption
     • Radiographically
       • Radiolucency does not move with different radiograph views
       • No tramlines visible
     • Stimulus
       • Infected pulp
         • Toxins damage pre-dentine layer
         • 1) Death of odontoblasts -> no further dentine deposition
           • Trauma -> pressure from bleeding/clot formation
           • 2) Giant cells colonise & transient root resorption occurs
             • 3a) Resorption arrests if pulp recovers (no further inflammation) or Pulp dies
             • 3b) Chronic pulp inflammation -> Progressive resorption
     • Diagnosis
       • Pulpitis signs?
       • Trauma history
       • Pink spot on tooth
       • Radiographic
     • Treatment = RCT
       • CaOH for 1wk before obturation

3. Replacement resorption = Ankylosis

   • = complete fixation of joint by bony union (no PDL, root fused to bone)
   • Diagnosis
     • High metallic percussion note
     • Rock-solid tooth
     • Radiographically
       • loss of PDL
       • Root merges with bone (moth eaten)
   • Cause = Trauma -> damaged PDL
     • Luxation
     • Avulsion
   • Treatment = none
     • Tooth crown may fracture or decoronate