What is a CBCT scan, and how does it differ from a panoramic X-ray?
Cone-beam computed tomography (CBCT) is an X-ray examination that shows the teeth and jawbone in three-dimensional slices. According to Guy’s and St Thomas’ NHS Foundation Trust, it provides information that ordinary dental X-rays cannot, such as the exact shape and structure of the jawbone, and helps decide whether implants are possible.
The panoramic X-ray (OPG), which many patients know from their own dentist, shows the whole jaw in one two-dimensional image. Jacobs and colleagues stress in BMC Oral Health (2018) that two-dimensional images cannot depict complex three-dimensional structures.
| Feature | Panoramic X-ray (OPG) | CBCT | Medical CT |
|---|---|---|---|
| Image | two-dimensional overview | three-dimensional slices | three-dimensional slices |
| Bone width from cheek to tongue | not visible | visible | visible |
| Field of view | whole jaw | adjustable from a small region to the whole face | large region |
| Radiation dose | low | higher than OPG, lower than CT | highest |
What is assessed on a CBCT scan before implants?
According to Jacobs and colleagues, CBCT is used to assess bone volume and shape, anatomical boundaries and the proximity of important structures. The consensus statement of the International Team for Implantology (ITI, 2013) notes that CBCT can be the imaging of choice when disease of the jawbone or sinus is suspected, and recommends a radiographic guide during the scan so that the planned tooth position is visible on the image. Planning usually looks at:
- Bone height: it determines the implant length. If there is too little in the back of the upper jaw, a sinus lift may be needed.
- Bone width: the thickness from cheek to tongue cannot be seen on a panoramic X-ray. If bone is missing around the implant site, a bone graft may be considered.
- Nerve canal in the lower jaw: the position of the canal carrying the nerve to the lower lip and chin is measured.
- Sinus: in the back of the upper jaw, the position of the sinus floor and the condition of the sinus are assessed.
Guided implant surgery is also planned on the three-dimensional scan.
Is a CBCT scan needed before every implant?
Not necessarily, but it is often useful, and the sources place the emphasis differently. The 2012 position statement of the American Academy of Oral and Maxillofacial Radiology recommends cross-sectional imaging for all implant sites and CBCT as the preferred method. The ITI consensus statement (2013) asks for the decision to be made after a thorough examination and according to the individual patient’s needs: CBCT is indicated when information beyond the examination and conventional X-rays is required. It also notes that a clinically meaningful advantage of CBCT over two-dimensional methods for implant survival or complications has not yet been shown.
Jacobs and colleagues name situations in which CBCT is particularly helpful: unusual anatomy, aesthetic challenges in the upper front teeth, insufficient bone volume and complex procedures such as bone grafting. The European Commission’s guideline (Radiation Protection 172) requires a history and examination before every CBCT scan and states that it should not be carried out routinely on everyone.
How much radiation does a CBCT scan involve?
The dose varies widely with the machine and the size of the field of view. The European Commission compiled effective doses for adults in Radiation Protection 172 (in microsieverts, µSv):
| Examination | Effective dose |
|---|---|
| Small intraoral dental X-ray | under 1.5 µSv |
| Panoramic X-ray | 2.7–24.3 µSv |
| CBCT, small and medium field of view | 11–674 µSv (median 61 µSv) |
| CBCT, whole face and jaws | 30–1,073 µSv (median 87 µSv) |
| Medical CT of the jaws | 280–1,410 µSv |
The guideline summarises this as: CBCT doses are generally higher than those of conventional dental X-rays and lower than those of medical CT. Guy’s and St Thomas’ translates a CBCT scan of the jaw into roughly 6 to 30 days of natural background radiation, and a medical CT of the same region into 63 to 154 days. Jacobs and colleagues recommend that the dose for implant planning should preferably correspond to 2 and at most 10 panoramic X-rays (20–100 µSv).
How is the dose kept as low as possible?
The American Dental Association (ADA) describes the ALARA principle: every scan must be justified by its benefit, and the dose is kept as low as reasonably achievable. According to the ADA, CBCT is the largest single contributor to diagnostic radiation in dentistry and should only be used when lower-dose methods cannot provide the necessary information. In practice this means:
- Limiting the field of view: the European Commission asks for the smallest field of view compatible with the clinical situation, and the ITI recommends restricting it to the region of interest wherever possible; a single implant rarely requires a scan of the whole face.
- Matching resolution to the question: according to Jacobs and colleagues, the resolution should be chosen according to age, anatomy and the clinical question.
- Avoiding repeat scans: the European Commission advises against repeating a CBCT scan without a new assessment of benefit and risk; the ADA recommends making a serious effort to obtain images from previous examinations.
On lead aprons: since 2024 the ADA no longer recommends thyroid collars for dental imaging, because rectangular collimation and correct positioning are more effective. If in doubt, ask how the practice handles this.
Can X-rays from home be used?
Existing images are valuable. The ADA recommends using images from previous examinations, and the European Commission advises against repeating CBCT without a new assessment. The ITI recommends systems that fully support the DICOM standard so that images can be transferred between different machines and software.
Ask your dentist at home for the image data itself, in the case of a CBCT scan in DICOM format on a CD, USB stick or as a download, not just the written report or a printout. If teeth have been removed or bone has been grafted since the scan, it no longer shows the current state of your mouth; whether a new scan is needed is decided by the dentist after the examination. What else to bring is listed in our guide documents for dental treatment in Türkiye.
What applies in pregnancy?
Say before any scan if you are or might be pregnant. The International Atomic Energy Agency (IAEA) recommends first considering an option without X-rays for women of childbearing age; if the scan is needed, it is taken with the lowest possible dose. According to the IAEA, the dose to the unborn child from dental X-rays including CBCT is between 0.009 and 7.97 µSv, usually less than it receives from natural sources in a single day. Since implants can usually be planned, the CBCT scan and the surgery are often postponed during pregnancy; see our guide dental treatment during pregnancy.
How is the CBCT scan before implants handled at Rönesans?
Our clinic has its own CBCT scanner; bone height, bone width and the distances to the nerve canal and the sinus are assessed in three dimensions, so you do not need to visit another facility for the scan. You can send existing images from home, such as a panoramic X-ray or a CBCT scan, on WhatsApp to +90 532 363 49 54 for a preliminary assessment; whether a new scan is needed on site is decided after the examination.
Our dentists review your case together on the basis of the examination and the CBCT scan, and you are treated by a dentist you know from the start. Before treatment starts, you receive a written treatment and cost plan, and when you leave, copies of your X-rays for your dentist at home. For the scan, you remove jewellery on the head and neck, glasses and removable dentures, as Guy’s and St Thomas’ also advises. The treatment process is described on our dental implants page, and planning your trips in the guide how many days to stay in Türkiye for dental implants.