Root Inclination and Today’s Orthodontics

Before orthodontic treatment can begin, it is important to obtain the precise mesiodistal angulation and faciolingual inclination for all teeth being treated. Current technology focuses the most on crown angulation and inclination in general, while the roots do not receive as much attention as they should. Positioning roots correctly is necessary for any orthodontic treatment that is of any use, but because orthodontists tend to focus on the position of the crown, not the root, optimum teeth alignment doesn’t always take place.

The roots are typically overlooked because roots do not directly affect the preferred esthetics of the face that an orthodontic patient is ultimately striving for. Research has indicated that it is still reasonable to suggest that positioning the roots in their right places in the basal bone may reduce the amount of relapse occurring after orthodontic treatment, which is a plus in itself.

Up to now, orthodontists have discovered that problems which occur with crown alignment which have been observed through radiographs are due to incorrect root angulation. It is of utmost importance that these problems are corrected sooner rather than later, as the whole aim of administering orthodontic treatment is to achieve proper and stable teeth positioning. This involves all parts of the tooth, including crowns and roots. However long it takes, patients are looking for a favorable facial appearance as the outcome.

Panoramic x-rays versus cone-beam computed tomography (CBCT) to determine root position

Throughout orthodontic treatment, panoramic x-rays have been used extensively to check root position, even though they are not known for their accuracy. This inaccuracy is allegedly due to distortions found in panoramic radiographs because of non-orthogonal x-ray beams that are directed at the targeted teeth.

Cone-beam computed tomography (CBCT) is a new and more accurate approach for getting images of the position and angulation of the teeth’s roots. They are able to take a 3D image of all the teeth and the roots with minimal exposure to radiation. This breakthrough should be of great interest to the orthodontic community and fulfils the main aim of orthodontic treatment, which is to manipulate misaligned teeth from malocclusion to being more esthetic, so that the complete tooth, crown and root are positioned so as to be both more functional and more esthetic.

A well used way to ensure ideal occlusion is Andrew’s six keys. Four of these keys, namely faciolingual, mesiodistal, occlusal gingival positions and axial rotation, are solely governed by the teeth’s crowns, which are generally relatively easy to monitor clinically. Despite this, crowns do not always indicate accurately enough the complete tooth inclination and angulation.

Mesiodistal angulation and faciolingual inclination can be better established if the orthodontist can get a 3D view throughout the orthodontic treatment process. It is not good enough to depend on imagery found from panoramic radiographs, as the images are often distorted. CBCT provides the accuracy that the orthodontic community really needs to minimize the treatment time of orthodontic teeth alignment solutions.

Why root angulations are important to the orthodontist

Detecting root angulation is important because the optimum position of the roots needs to be achieved so that each root sits independently from others and stands in a parallel position in relation to adjacent roots. It has been found that panoramic x-rays don’t necessarily show the root’s positions with enough accuracy. Some orthodontists notice issues in crown alignment after observing improper root angulations using radiographs. The American Board of Orthodontics issued a recommendation that assessing root angulations should be carried out. This assessment necessitates root parallelism and takes away points if the roots of adjacent teeth are not parallel to one another or make contact with one another. If the angulation of the roots can be detected they can be corrected by the orthodontist.

The process for using CBCT scans and software for detecting tooth angulation/inclination

Accurate diagnostic imaging is important for both orthodontic diagnosis and the planning of treatment. It is also an essential tool that permits the orthodontist to monitor closely the progress of orthodontic treatment. Today, CBCT is more frequently used to provide more complete images of orthodontic patients’ teeth and roots than the use of panoramic images and cephalograms. CBCT scanners have been in use for fifteen years. Orthodontists and dentists can locate inclination/angulation of the teeth using CBCT and compatible software. This is not necessarily a quick process, as it may take some time to locate and segment the roots.

Quality of CBCT scans for root angulation

The orthodontist may see some discrepancies in 3D CBCT images of root positions, but in contrast panoramic radiographs tend to offer false information. This makes 3D CBCT scans far more reliable than anything that has come before it to detect root angulation as well as images of the teeth and crowns.

Coming soon for orthodontists

At CephX, our aim is to help orthodontic practitioners globally to save valuable time by offering accurate dental imagery analyses. We offer an instant service which is made up of the highest quality cephalometric analysis that helps to improve productivity and efficiency in your practice. Currently, we provide a cephalometric analysis service for 2D cephalometric x-rays. The dental practitioner uploads the patient’s cephalometric x-ray scan, and within a matter of seconds he or she will receive the full cephalometric analysis. There are 2 more services we will be adding soon which offer automatic and instant results too. These are:

1. A cephalometric analysis service for 3D cephalometric scans using CBCT.
2. Teeth segmentation, including Root Recognition which provides information about every tooth, root direction, impacted tooth position and supernumeraries, using CBCT.