The Importance of Precise 3D Localization of Impacted Teeth Using CBCT in Orthodontics

An impacted tooth, i.e. a tooth which hasn’t completely erupted, is unlikely to do so because of its position in relation to adjacent teeth and nearby bone or soft tissue. Impacted teeth are most commonly the mandibular 3rd permanent molar, the maxillary permanent canine or, on occasions, the premolars. The impaction could be vertical, horizontal, mesioangular, distoangular and sometimes inverted, which is actually a rare occurrence. Inversion is quite extreme, as in this case the tooth has reversed its position and is upside down. In order for orthodontists or dentists to correctly treat this condition they need to be able to localize it precisely to make a treatment program easier to implement.

The cause of impacted teeth

Typically, a tooth becomes impacted when the patient’s mouth does not have sufficient space for it. The most likely teeth to become impacted are the wisdom teeth. Because they are the last to erupt, the jaw and mouth may have stopped growing, leaving no space for these newly erupting teeth. Maxillary canines, or cuspids, may also become impacted.

When the canine teeth are impacted, you may use eruption aids, such as braces to encourage the impacted teeth to erupt. If you are unable to get the impacted tooth to erupt it may need to be extracted and a dental bridge or implant can then be fitted into the space. Accurate imaging techniques are vital to determining possible treatment options.

When dentists and orthodontists need to localize impacted teeth

It’s difficult to see the topography of both the impacted tooth and the area around it without using a reliable imaging diagnostic tool. Up to now, before treatment could take place, 2D imaging techniques have typically been used to get dental imagery in order to make an accurate diagnosis and for localizing the non-erupted teeth so that treatment can be planned. More recently, it has been discovered that 2D radiography has not been sufficient to determine the precise location of the problem, including what the impact is on adjacent teeth, and the structure of the affected tooth’s roots, which is key to starting any type of useful treatment.

The cephalogram, or ceph, has been in use by orthodontists as the usual method of getting dental imagery for analyzing the dental, skeletal and soft tissue relationships in patients for a number of years. 2D, or direct cephalometric x-ray technology, has been used successfully for many decades by orthodontists. Currently, orthodontists still use this method, although some dental clinics have begun to use 3D cephalometric analysis as an addition. If a patient is seeking to get teeth straightened through the use of braces treatment or aligners, the better the analysis of the patient’s teeth, the better the subsequent treatment program initiated.

The most recent diagnostic tools used by dentists and orthodontists

At the forefront of diagnostic tools, as well as computed tomography (CT) and 3D tools, is cone-beam computed tomography (CBCT), which has been shown to produce high-quality 3D images that provide an accurate diagnosis with a minimum amount of distortion. The cost factor is important, but this technique compares favorably with others and it clearly reduces radiation exposure to much lower levels than other CT technology. CBCT has shown its capability to improve diagnosis and its contribution to modifying treatment planning for impacted teeth. CBCT has shown it can more accurately localize a tooth, evaluate its position in relation to other teeth, assess the follicle size and analyze resorption of any adjacent teeth. A dentist working alone needs to annotate teeth, including impacted teeth, which can be hard work because imaging software is used which is then interpreted manually.

Studies have indicated that CBCT provides much more information than other methods for localizing impacted teeth, root resorption, cleft palate and 3rd molar assessments. CBCT also provides better images of roots, so it’s a valuable tool for the assessment of pre-orthodontic or post-orthodontic root re-sorption. It has also been shown to be the best option for determining the angulations of roots.

The increase in availability of CBCT technology has meant that the greater use of it has led to further development of the technique by dentists and orthodontists leading to better treatment outcomes for patients. As far as impacted teeth are concerned, images obtained through CBCT are able to accurately determine their angulation and buccal-palatal location. It is also able to pinpoint the exact location of impacted teeth in relation to adjacent teeth’s roots as well as the extent of resorption.

Being able to get an accurate view of these features is important in planning appropriate treatment to move the impacted tooth in the arch and lower the risk of root resorption taking place in adjacent teeth. Different kinds of imaging software permit CBCT image reconstruction in several planes, which offers a more precise view of the position of the impacted tooth.

When CBCT should be used

Cone-beam computed tomography (CBCT) has taken over more recently as an important method of collecting 3D volumetric data. However, it is typically considered that it should only be used in certain cases when more conventional radiography is unable to provide adequate diagnostic information. The sort of specific situations include those patients who suffer from a cleft palate, assessing the position of an un-erupted tooth, a supernumerary tooth, identifying root resorption and planning orthognathic surgery.

2D diagnostic imaging, like traditional radiographs, cephs, photos and videos, has been used routinely to provide orthodontic diagnosis for many years, but not with complete accuracy. The limitation of this type of imaging has been overcome by CBCT and is likely to be used more often in the future. It’s a useful diagnostic tool for planning braces and aligner treatment as it gives a better overall image of the structure of the teeth.

Artificial intelligence in the dental world

As more and more devices are used to assess the status of teeth, so Artificial Intelligence (AI) and machine learning are starting to dominate all areas of life. AI is revolutionizing the transforming of unstructured data into useful information which is likely to become just as relevant to the dental industry. AI provides an end to end solution which in the end will provide better outcome for patients.

At CephX, we help orthodontic practitioners throughout the world save valuable time by providing accurate dental imagery analyses and interpretations. We offer an immediate service which is the highest quality cephalometric analysis that improves your practice productivity and efficiency.

Currently, we offer 2D x-ray analysis only, but soon we are opening our doors to 3D analyses, as well as immediate and accurate 3D teeth annotation, including the localization of impacted teeth.

Read more about History of Cephalometric Analysis – Using Our Heads
and Retainers and Maintenance: Preserving Your Patients’ Investment