Root resorption is a process of multifactorial origin related to the loss of tooth structure at the apices of the roots of teeth in response to:
- Mechanical
- Inflammatory
- Autoimmune
- Infectious Stimulus
Genetic susceptibility accounts for 2/3 of the variation in external apical root resorption with some individuals being more susceptible to root resorption due to DNA polymorphisms within/near candidate genes in the pathway implicated in external apical root resorption.
Mechanical causes of root resorption is caused by orthodontic treatment, where forces are applied to teeth to effect teeth movement and alignment. The direction, duration, and magnitude of the force all have an impact on the degree of root resorption. When examined under a microscope, 90% of patients who undergo orthodontic treatment will exhibit some signs of root resorption. However the average amount of root resorption is small and less than 2mm, this does not have a long term impact on the longevity of the tooth. However in a small percentage of patients who are genetically more susceptible to root resorption, orthodontic treatment can cause root resorption of more than 4mm or 1/3 of the original root length. To ascertain your risk for root resorption, an X-ray will be taken to assess for any incidental findings of root resorption which may suggest a predisposition for root resorption.
Inflammatory and infectious stimuli may be caused by either an injury such as trauma to the teeth or tooth decay resulting in bacteria reaching the apical area of the tooth root.
Autoimmune stimulus means that the body's own immune system mistakenly attacks itself. As the pathway involved with external apical root resorption involves cells that help fight inflammation. An overactive immune system may wrongly activate this pathway and cause root resorption.
