ROOT RESORPTION IN ORTHODONTICS

Description

Root resorption is a condition characterized by a partial loss of root cementum and dentin.
Root resorption of the deciduous dentition is a physiological process and it is a necessary precursor to the eruption of permanent teeth.
Permanent teeth root resorption is a pathological inflammatory process and it can be affected by several factors

Apical root resorption can be also related to an orthodontic treatment and it can be present during the treatment or at the end of it.

This root resorption is called orthodontically- induced inflammatory root resorption (OIRR) and it is considered a distinct pathologic process.

Patient-related and treatment-related factors are involved in the onset and progression of this root resorption.1. Cemental or surface resorption with remodeling. In this process, only the outer cemental layers are resorbed, and they are later fully regenerated or remodeled. This process resembles trabecular bone remodeling.

2. Dentinal resorption with repair (deep resorption). In this process, the cementum and the outer layers of the dentin are resorbed and usually repaired with cementum material. The final shape of the root after this resorption and formation process may or may not be identical to the original form.
. Circumferential apical root resorption. In this process, full resorption of the hard tissue components of the root apex occurs, and root shortening is evident.
Orthodontic forces applied to the biologic system act similarly on bone and cementum, which are separated by the periodontal membrane. If there are no differences in the biologic behavior of these two organs, both would resorb equally.

Since cementum is more resistant to resorption compared with the more vulnerable bone, applied forces usually cause bone resorption, which leads to tooth movement. However, resorption of the cementum and dentin may also occur
Several theories explaining the resistance of the dental tissues, especially cemental resistance to resorption, exist.

It is documented that the uncalcified mineral tissues, osteoid, precementum, and predentin are resistant to resorption and may initially prevent loss of root tissue.

These layers might contain noncollagenic materials, eg, the cells themselves, that possess potent anticollagenase propertiesAfter extensive research in this field, mainly with tooth replantation models, Andreasen, relates surface resistance to the innermost cellular layer of the periodontal ligament.

This layer supplies the protective mechanism to the root, as well as the potential for a repair.
The cementoblasts, fibroblasts, osteoblasts, endothelial, and perivascular cells are included in this layer
However, continuous pressure will eventually lead to resorption of these areas
Root resorption occurs when pressure on the cementum exceeds its reparative capacity and dentin is exposed, allowing multinucleated odontoclasts to degrade the root substance.

Acc to Rudolph ,Resorption typically attacks the root tip and