CBCT, also known as C-arm CT, Cone Beam Volume CT or flat panel CY is a medical imaging technique, like a conventional CT scan. It provides fast and accurate visualization of bony anatomical structures in three dimensions. It is essentially X-ray computed Tomography where the X rays are divergent, forming a cone. Unlike traditional dental x-rays that are flat images, CBCT scan can provide multiple images of the teeth, soft tissues, bone and nerve pathways. The image quality is better due to reduced scatter radiation. These images help compile exact 3D images of various angles of the face and jaw. It also allows the dentist to zoom into specific maxillofacial structures with alternate angles for clearer evaluation.
CBCT is important in planning and diagnosis in implant dentistry and interventional radiology among other things. In dentistry, it is used in oral surgery, endodontics and orthodontics.
CBCT is an important tool in image-guided radiation therapy for patient positioning and verification. Nearly 600 distinct images can be captured by rotating the CBCT scanner around the patient's head. In interventional radiology, a single 200 degree rotation over the region of interest provides volumetric data. The scanning software collects the data and reconstructs it, producing a digital volume composed of three dimensional voxels of anatomical data that can be manipulated and visualized with specialized software.
CBCT offers invaluable information in planning and assessment of surgical implants. A dental cone beam scan is the preferred method for pre surgical assessment of dental implant sites. Since CBCT is a 3D rendition, there are several structures that can be viewed with this facility, which are not available with conventional 2D radiology. CBCT offers an undistorted view of the dentition. That is why it is used for accurately visualizing both erupted and non erupted teeth. It is also used in tooth root orientation and anomalous structures.
Use of CBCT in Interventional Radiology (IR)
The scanner is mounted on a C arm in the IR suite offering real time imaging. Since this can be done on a stationary patient, it eliminates the time spent to transfer a patient from the Angiography suite to a conventional computed Tomography scanner. It also facilitates many applications of CBCT during IR procedures. Both primary and supplementary form of imaging can be done with CBCT. For fluoroscopy and soft tissues, it can be very helpful during complex procedures to reduce patient's radiation exposure.
Clinical applications of CBCT
In hepatocellular carcinoma, CBCT contrast confirms that the proper artery is selected to deliver the therapy. For benign prostatic hypertrophy BPH, CBCT provides soft tissue details needed to visualize prostatic enhancement, identify duplicated prostatic arteries and avoid non target embolization. During abscess drainage, CBCT confirms needle tip location after placement under ultrasound and confirms drain placement by revealing contrast injection into the desired location.
For adenoma adrenal vein sampling, contrast enhanced CBCT shows perfusion of the adrenal gland to confirm catheter placement for obtaining a satisfactory sample. During stent placement, CBCT improves the visualization of intracranial and extracranial stents. CBCT guides needle placement and allows diagnostic accuracy, sensitivity and specificity in lung nodules. After correction of vascular anomalies, CBCT sensitively detects small infarcts in tissue during the procedure to prevent further shunting.
Although it is a compact, faster and safer version of the regular CT, dental CBCT delivers more radiation than conventional dental X rays. Even properly shielded CBCT exposes patients to radiation many times more than 2D digital dental x rays. However, improved outcomes at lowered cost and time saving, reduced morbidity and reduced need for exploratory procedures and other such benefits of CBCT continue to make it popular with practitioners.
A cosmetic dentist is a general dentist with an added dimension. Besides performing the functional requirements of a dentist, the cosmetic dentist pays close attention to the appearance of the dental work. Cosmetic dentistry is not generally taught in dental schools as part of the normal curriculum. A cosmetic dentist, in addition to qualifying as a dental graduate needs to pursue additional training after graduation and undergo specialist accredited training in the field. Cosmetic dentistry covers a multitude of procedures that improves the beauty and health of one's smile. Cosmetic dentistry can be as simple as re-contouring of one or more teeth or as comprehensive as an aesthetic and functional rehabilitation. Cosmetic dentistry can brighten a dull teeth, whiten stained teeth, close gaps between teeth, repair chipped teeth, mask metal fillings and straighten crooked teeth.
Techniques adopted by a cosmetic dentist
A cosmetic dentist adopts latest dental techniques to improve the treatment and reduce the 'chair time' of the patient. Some of the latest techniques are:
Temporomandibular Joint Disease
Temporomandibular Joint Disease or TMJ is a group of conditions that involve the temporaomandibuluar joints. These joints are located in front of each ear and connect the lower jaw bone to the skull. The temporomandibular joints allow sideward and up-and-down movements such as speaking, chewing food, biting and speaking. A person suffering from Temporomandibular joint disease has pain in the jaw and surrounding tissues that make movement painful. TMJ is also referred to as myofacial pain dysfunction and Costen's syndrome. Mandibular muscle tension caused due to stress can be a cause for TPD. Certain triggering factors for TMJ may be teeth grinding, teeth clenching, dental problems and high stress.
It is noticed that more women, especially in their childbearing years tend to be affected by TMJ than men. Some form of arthritis, hormones, autoimmune conditions and low-grade infections are thought to be the causes for Temporomandibular Joint Disease. There is a dull ache in the jaw joint and ears. Persons suffering from temporomandibular joint disease suffer headaches and pain in the neck, shoulder and back. They may find it difficult to open the mouth comfortably or notice locking of the jaw. Swelling is sometimes noticed on the sides of the face. There might be ear pain or ringing in the ears. These symptoms may last a few weeks.
A diagnosis of TMJ can be made after an examination of the cheek muscles for any neurological symptoms. The physician will check for any joint clicking sounds and assess the range of motion of the mandibular joints. Analgesics or NSAIDs are prescribed to reduce pain and discomfort. Muscle relaxants such as diazepam are used to reduce muscle spasms. Therapy such as massage, exercise and electrical stimulation can aid in improving the strength and motion of the mandibular joints. Dental therapy such as orthodontics can help in rectifying an abnormal bite and teeth misalignment. Cortisone injections are given to those who do not respond to any other treatment. Patients suffering temporomandibular joint disease can alleviate the pain and other symptoms by eating soft food, applying ice or moist heat and avoiding extreme jaw movements that can be painful. The jaw must be rested.
Bibliography / Reference
Collection of Pages - Last revised Date: February 18, 2018