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micro-CT for Dental Applications

A two-part interview with Dr. Marco Versiani, University of Sao Paulo, Brazil

Using micro-CT Imaging to Understand Tooth Anatomy

Micro computed tomography, commonly referred to as micro-CT is a non-destructive 3D X-ray imaging technique. It provides high resolution images of the internal structure of a sample. It usually does not require sample preparation and the complete internal structure of the specimen can be visualized three-dimensionally in a single scan. In addition, the sample is left intact, so it can be further studied using other techniques.

Although on a much smaller scale and capable of much greater resolution, the micro-CT is based on the same principles as the CAT scanners used in hospital to acquire images of human internal organs. Similarly, the smaller dental cone beam computed tomography (CBCT) scanner allows dentists to acquire more detailed 3D images of teeth, bone, and nerve pathways when a regular X-ray is not sufficient.

In a recent interview Dr Marco Versiani, an invited researcher at the Dental School of Ribeirão Preto, University of Sao Paulo, described how micro-CT facilitates his research to further understand the influence of root canal anatomy in several endodontic procedures.

Endodontics is the branch of dentistry that specialises in the root canal and tissues surrounding the roots of a tooth. The root canal is the space inside a tooth that contains the dental pulp tissue and this is the site of endodontic procedures. Therefore, in the same way that anatomy is the foundation of medicine, root canal anatomy can be considered the foundation of the endodontics specialty.

Being accurate and non-destructive, micro-CT has provided many impressive and significant results in dental research. Micro-CT has the added advantage that it allows the same target area of the same sample to be assessed at different steps of an experimental procedure. This enables the use of more reliable controls in studies, which makes the data obtained more robust. Micro-CT is a more accurate imaging tool than CBCT, but can only be used for research purposes. However, it has proved extremely valuable for validating in vivo clinical data obtained using CBCT.

Micro-CT has overcome key limitations of conventional methodologies, such as sectioning and 2D radiography, but also offers additional advantages. It can be used to evaluate opaque objects, like teeth, both qualitatively and quantitatively. Mathematical algorithms from micro-CT technologies allow evaluation of parameters that is impossible to precisely acquire using traditional tools such as sectioning or clearing techniques. For example, micro-CT can be used to determine the volume, surface area and 3D geometry of the root canal.

In 2011, the Dental School of Ribeirão Preto at University of Sao Paulo, launched the Root Canal Anatomy Project (http://rootcanalanatomy.blogspot.com) to share their research findings, as micro-CT equipment is not widely available in all countries. Dr Marco Versiani explained "our intention when we created this project was to offer for free images and videos developed in our SKYSCAN machine to professors, students and also clinicians throughout the world". Nowadays, the website has more than 1.5 million visitors and the available material were downloaded more than 300000 times. Their research has also recently been published in a book entitled "The Root Canal Anatomy in Permanent Dentition".

Dr Marco Versiani and his team use the Bruker SKYSCAN 1174, the world's most compact X-ray micro-CT equipment. This scanner can be adjusted for imaging samples of different densities and scans an entire sample in a matter of minutes, making it a versatile research tool. In addition, it is accompanied by software that provides fast volumetric reconstruction, quantitative analysis and realistic 3D visualization.

The main reasons that led to the Bruker-microCT company being chosen over its competitors were the ease of use and the user and technical support available, since it was for use by dentists who may not have a great understanding of the science behind imaging technologies.

Dr Marco Versiani commented "the learning curve of the software is lower than the other companies... 24 hours a day, 7 days a week we are able to talk and to send our doubts to the scientists from SKYSCAN Bruker-microCT". Also "Every year the company promotes a user meeting in Belgium and it is an outstanding opportunity to meet people from all around the world and to share knowledge. And this is an important aspect of being a Bruker-microCT user".