Cone Beam CT Scanner
Cone Beam CT Technology for Endodontics - Why Guess?
Our on-site Cone Beam CT (CBCT) Scanner allows us to image the inside, and around your tooth in 3D. This enhances diagnosis as studies have shown 30%-40% of abscesses cannot be visualised through standard 2D x-rays. Fractures and missed canal anatomy can also be identified bringing increased clarity to treatment planning and the chances of successful treatment.
Having been one of the first endodontic practices in the UK with its own 3D scanner, we updated our machinery to the Veraview X800 manufactured by Morita, designed to be the world's first "Total Performance Imaging" system, providing outstanding image quality ensuring a precise and reliable diagnosis even in the most demanding cases.
The cone beam CT scanner is central to the way in which we practice at the Academy of Advanced Endodontics and provides reliability in diagnosis and subsequent treatment planning. Richard has reported on thousands scans of teeth with endodontic issues. His expertise in this relatively new and effective diagnostic modality has resulted in the practice becoming a referral centre for complex cases used by both endodontists and general practitioners.
Overview
Root canal treatment is carried out deep inside teeth in order to remove either a dying nerve or infected material that has entered the nerve spaces. The disease process inside these spaces damages the bone of the jaw surrounding the tooth.
For decades the only way to assess these areas accurately and to diagnose disease and plan treatment is through the use of x-rays. Traditionally, an x-ray beam is passed through the jaw and teeth. The relative absorptions of the radiation are projected onto an x-ray sensitive film placed into the mouth. The resultant image, which requires developing, will show the complex shapes of the tooth in one plane only, areas of decay, and bone damage that has occurred, but sometimes only if it has progressed to a relatively advanced stage.
We have integrated into the practice the newest, next generation of x-ray machines. A Cone Beam CT scanner – the Veraview X800 from Morita (Japan). We are now able to clearly see the complete root canal anatomy, roots and surrounding bone by taking slices through the tissues. This enhances our ability to predict what is inside the tooth, and disease around the tooth can be more accurately diagnosed. This leads to enhanced treatment planning and the ability to target treatment where it is necessary, leading to quicker and easier treatment and often reducing the overall costs of treatment.
Technology
The problem with standard intra-oral x-rays, whether standard or digital, is that the image is a two-dimensional representation of a three dimensional complex block of human tissue. The image flattens all the anatomical detail so that we can only guess at the true 3-dimensional shapes within. This squashed image hides the fine detail of root canal anatomy, the roots themselves, and the surrounding bone that can often be the key to diagnosing difficult pain cases. However, as the best system we have, endodontists in particular, have acquired great skills in being able to diagnose and predict the shapes beneath from these images.
Many times, though we are left providing a ‘best guess’ and have to carry out invasive treatment procedures to try and learn what lies beneath. CT scanners have been around for quite some time in general medicine, but they require huge machines that deliver large quantities of radiation. The innovation of the Cone Beam CT technology is that it can take small volume cylindrical scans of 4 X 4cm, suitable for 2-3 teeth analysis. The limited volume together with the digital plate reduces radiation to one of the lowest currently possible for a CT scan.
Dental X-Ray Radiation Risk, Background Radiation and CT machines
X-rays are present in the atmosphere (cosmic radiation) and background radiation also comes from geological structures. Medical x-ray machines produce significant amounts of radiation and the principle governing rule to exposure is to always keep this as low as reasonably possible, employing a favourable risk-benefit ratio.
The level of risk varies according to age and the parts of the body exposed to the radiation. Some areas are more sensitive to others. Dental x-rays generally carry less risk as the jaws are less sensitive areas. The table below (www.xrayrisk.com) calculates the additional risk of cancer from a 4x4cm 3D CBCT scan to an average 40-year-old female. The baseline risk of a cancer is 37.5% (1 in 3) for women and a scan will add a further risk of 0.000285% (1 in 350,887). That is one hundred times less risk than being hit by a meteorite (1 in 3,200).
As a comparison consider that the estimated lifetime risk of being killed in a road traffic accident in the UK is 0.42% (1 in 240 chance) or by a bolt of lightning is 0.001% or 1 in 100,000 chance.
In terms of the amount of radiation, or the dose, it might be useful to compare the doses of various sources of radiation. From dosimetry carried out on our scanner the calculated average dose of the smallest scan was 0.028mSv (Morita X-ray Dosage Information). Based on these figures a 4x4cm Morita scan is equivalent to 4 days of background radiation living in London or just over 1 day living in Cornwall.
Source of exposure Dose
Dental x-ray 0.005 mSv
100g of Brazil nuts 0.01 mSv
Chest X-Ray 0.014 mSv
Transatlantic Flight 0.08 mSv
UK annual average radon dose 1.3 mSv
CT scan of the head 1.4 mSv
UK average annual radiation dose 2.7 mSv
USA average annual radiation dose 6.2 mSv
UCT scan of the chest 6.6 mSv
Average annual radon dose to people in Cornwall 7.8 mSv
The radiation exposure doses below are taken from an article in the International Endodontic Journal*
*Patel S, Dawood A, Pitt Ford T, Whaites E. The potential applications of cone beam computed tomography in the management of endodontic problems. International Endodontic Journal, 40, 818–830, 2007