Root Resorption: Causes

Pathogenesis (development of disease)

Resorption can occur within a dentition on one or more teeth. Mechanisms and causes of root resorption have not been definitively determined. Quite a few possible triggers are under discussion. Root cementum or dentin is degraded by odontoclasts (somatic cells that degrade dentin), which are of the same cell type as osteoclasts (somatic cells that degrade bone) and also share their ultrastructural and histochemical properties. However, while bone undergoes lifelong remodeling processes, tooth roots are protected against resorption. In addition to other factors, root coverage by pre-cement (root surface) or predentin (root canal) plays an important role. A loss of integrity of the root coverage leads to resorption. Main factors

  • Trauma
    • Dental accident
    • Periodontal therapy (procedures related to the analysis, diagnosis, prevention and treatment of periodontitis/inflammation of the periodontium).
    • Pressure (orthodontics, impacted teeth/occlusion of teeth, cysts, tumors).
  • Infection of the root canal
  • Invasive tissue

Etiology (causes)

Biographical causes

  • Genetic diseases
    • Hereditary hyperoxaluria (primary hyperoxaluria) – inborn error of metabolism with autosomal recessive inheritance in which there is too much oxalate in the urine [aggressive external resorptions due to inflammatory response to calcium oxalate deposits in the periodontium] [Moskow 1989]
  • Genetic predisposition
    • Abnormal root shape/length [apical (“affecting the root tip”) resorption]
    • Ectopic (“to be found in an unusual place”) erupting teeth (pressure)
    • [in discussion: apical/lateral root resorption; internal resorption]
  • Hormonal factors
    • [in discussion for internal absorption:]
    • Pregnancy

Causes due to disease

  • Allergies [apical resorption]
  • Bronchial asthma [apical resorption]
  • Bruxism (teeth grinding) [cervical resorption]
  • Habits (damaging habits in which jaw deformities may occur) [apical resorption].
  • Herpes zoster [under discussion for internal resorption]
  • Hyperparathyroidism (hyperparathyroidism of the parathyroid gland).
  • Idiopathic (diseases with unknown cause) resorption due to unexplained immunological processes.
  • Impacted tooth (trapped tooth → pressure) [lateral resorption].
  • Subsequent tooth germ [physiological deciduous tooth root resorption]
  • Neighboring tooth [undermining resorption of a deciduous tooth]
  • Occlusal trauma (damage to the periodontium (tooth-supporting apparatus) due to overloading/misloading of a tooth with a normal periodontium).
  • Periodontitis (inflammation of the periodontium) [external resorption].
  • Pulp necrosis (death of the dental pulp), partial [metaplastic internal resorption].
  • Pulpitis dental neuritis), chronic [internal resorption/internal granuloma]
  • Trauma (dental accident) with damage to cementum, dentin and/or periodontium [infection-related resorption] [internal resorption/internal granuloma].
    • Extrusion (“lengthening of a tooth”).
    • Contusion (“damage to a tooth by direct, blunt force from the outside”).
    • Loosening
    • Lateral dislocation (lateral misalignment)
    • Infraction (collapse of a bone, incomplete fracture).
    • Intrusion (tooth is pushed into the bone by external force).
    • Extraoral (“outside the oral cavity”) retention after total dislocation (knocking out of a tooth)/avulsion (the tooth (with root) has completely dislodged from its bone compartment)
    • Germ invasion
    • Root fracture (root fracture)
  • Tumor (→ pressure)
  • Injuries to the alveolar bone
  • Root canal infection
    • + vital tissue in the area of resorption [internal infection-related resorption].
    • + passing the infection into the periodontium (periodontium) [external infection-related resorption].
  • Root cementum damage
    • [Limitation to <20% of surface area: external transient resorption]
    • [ > 20 %: external replacement resorption, ankylosis (“fusion of the teeth with the jawbone”)]
    • + sulcular infection (inflammation of the gingival furrow) [under discussion for external invasive cervical resorption/ECIR].
  • Tooth eruption (→ pressure)
  • Cyst (→ Pressure)

Laboratory diagnoses – laboratory parameters considered independent risk factors.

  • Hypocalcemia (calcium deficiency) [apical/lateral absorption].
  • Vitamin A deficiency [under discussion for internal absorption]

Operations

  • Periodontal therapy (procedures related to the analysis, diagnosis, prevention and treatment of periodontitis/inflammation of the periodontium).
  • Tooth replantation (reimplantation of a tooth).
  • Tooth transplantation
  • Surgical procedures [trauma-induced resorption]
  • Éinterventions at the enamel-cement junction [cervical resorption].

Other causes

  • Desmodont damage (periodontal damage) due to extraoral (“outside the oral cavity“) dry storage of a totally luxated tooth prior to replantation [replacement resorption].
  • Endodontic treatment (treatment of the root canal system including the root tip) [apical resorption].
  • Internal bleaching (bleaching) [under discussion for cervical resorption]
  • Orthodontic treatment (→ pressure) [apical/cervical/internal resorption]
  • Physiological mesial migration of teeth (turning of teeth towards the center of the jaw or even forward from the midline of a jaw).
  • Pulp capping (via capping of the pulp), direct [under discussion for internal resorption].
  • Pulpotomy (endodontic treatment (treatment of the pulp) to remove the bacterially infected crown pulp (pulp in the crown area of the tooth) while preserving the root pulp vital (alive)) [under discussion for internal resorption]
  • Restorative therapy [under discussion for internal resorption]