--- title: "CBCT vs OPG X-ray UK | Orthodontic Scan Comparison" url: https://virtualconsultant.online/guides/cbct-vs-opg-xray-uk description: "Compare CBCT, OPG and lateral cephalometric X-rays for orthodontic diagnosis, including what each scan shows, radiation dose." updated: 2026-08-27T00:00:00Z publisher: Virtual Consultant Online --- Records X-rays Safety # CBCT vs OPG X-ray UK Orthodontic X-rays should be chosen for a clear clinical reason. CBCT gives 3D detail, while OPG and ceph images answer many routine questions with lower exposure. [Start Photo Assessment](https://virtualconsultant.online/evaluations/quote) [Compare Costs](https://virtualconsultant.online/costs) ## What does an OPG show in orthodontic assessment? An OPG (orthopantomogram or dental panoramic tomogram) is a 2D curved-plane X-ray that images the entire dentition, jaws, and surrounding structures in a single exposure. For orthodontic purposes it shows the number, position, and stage of development of all teeth including unerupted and impacted teeth; root length and shape; bone levels; the temporomandibular joints; wisdom teeth; and any pathology such as cysts or root resorption. It is the most common radiograph taken as part of orthodontic records and is routinely justified before any comprehensive course of orthodontic treatment. The radiation dose from a modern digital OPG is approximately 2 to 4 microsieverts — equivalent to a few hours of background radiation or a short domestic flight. ## What does a lateral cephalometric radiograph show? A lateral cephalogram (lateral ceph) is a standardised 2D profile X-ray taken at a fixed distance with the head in a reproducible position using a cephalostat. It allows precise measurement of jaw relationships, incisor inclination, facial proportions, and skeletal pattern. Cephalometric analysis quantifies the angle of the upper and lower jaw relative to the cranial base, the degree of overjet, the inclination of the upper and lower incisors, and the vertical facial height. This information is essential for planning extraction cases, overjet correction, jaw surgery assessment, and growth modification. A lateral ceph is not always required — it is most clinically valuable when a skeletal discrepancy is suspected or when jaw surgery is being considered. The dose is approximately 3 to 6 microsieverts. ## When is CBCT (cone beam CT) needed in orthodontics? CBCT provides three-dimensional information about the dentofacial structures that two-dimensional radiographs cannot. It is clinically justified in specific scenarios: precise localisation of impacted canines or other impacted teeth where the relationship to adjacent root surfaces is unclear from a 2D image; assessment of root resorption during or after treatment; evaluation of supernumerary teeth or odontomes in complex positions; airway assessment for sleep apnoea planning; pre-surgical assessment of the temporomandibular joints; and assessment of bone volume and anatomy before miniscrew or implant placement. CBCT should not be used as a routine imaging modality in place of 2D radiographs when 2D imaging would adequately answer the clinical question. UK and European guidelines (SEDENTEXCT, FGDP) are explicit that CBCT is only appropriate when the clinical benefit justifies the higher radiation dose, which ranges from approximately 20 to 200 microsieverts depending on field of view. ## What is the ALARA principle and why does it matter for orthodontic imaging? ALARA stands for As Low As Reasonably Achievable. In UK dental and orthodontic practice, it is the guiding principle for radiation protection and is enshrined in the Ionising Radiation (Medical Exposure) Regulations 2017. It means that each radiograph should be clinically justified — the benefit must outweigh the risk — and that the lowest dose technique sufficient to answer the clinical question should be selected. In orthodontic practice this means: preferring digital OPG and lateral ceph over film-based equivalents (lower dose); using the smallest CBCT field of view that covers the area of interest rather than a full dentofacial scan; and not taking radiographs at routine intervals simply by protocol when there is no specific clinical indication. Patients are entitled to ask why a radiograph has been recommended and what information it will provide that affects their treatment plan. Orthodontists operating within a defined population, such as children, have additional responsibilities to minimise cumulative exposure. ## How do orthodontic images compare in radiation dose? To contextualise orthodontic radiation: a single bitewing X-ray delivers approximately 1 microsievert; a periapical film 1 to 3 microsieverts; a digital OPG 2 to 4 microsieverts; a digital lateral ceph 3 to 6 microsieverts; a small field-of-view CBCT approximately 20 to 50 microsieverts; and a large field-of-view CBCT up to 200 microsieverts. Annual background radiation in the UK from natural sources is approximately 2,700 microsieverts. The combined OPG and lateral ceph taken at the start of a comprehensive orthodontic course represents a very small fraction of annual background exposure. CBCT at a small field of view is still within a manageable dose range when clinically justified but should not be used routinely. These figures are approximate and vary by equipment, technique, and patient anatomy. ## What other imaging might be used during orthodontic treatment? Beyond OPG, lateral ceph, and CBCT, orthodontists occasionally use intraoral periapical radiographs to assess specific teeth in more detail than an OPG permits — commonly to monitor root resorption around specific incisors, to assess the eruption path of impacted teeth, or to evaluate the apical area of a tooth of concern. An anterior occlusal radiograph provides a 2D view of the upper or lower front region and is sometimes used for upper canine localisation as an alternative to periapicals. Digital dental models (intraoral scans) have largely replaced plaster study models at progressive practices and provide 3D tooth measurements without any radiation exposure. Photography is a non-ionising part of orthodontic records that documents soft tissue profile, smile, and dental occlusion. ## Useful related pages [Orthodontic X-ray Radiation UK](https://virtualconsultant.online/guides/orthodontic-xray-radiation-uk) [Orthodontic Records UK](https://virtualconsultant.online/guides/orthodontic-records-uk) [Orthodontic Treatment Plan](https://virtualconsultant.online/guides/orthodontic-treatment-plan) [Wisdom Teeth and Braces UK](https://virtualconsultant.online/guides/wisdom-teeth-and-braces-uk) [Impacted Canine Orthodontics UK](https://virtualconsultant.online/guides/impacted-canine-orthodontics-uk) [Get a Virtual Consultation](https://virtualconsultant.online/evaluations/quote) This guide is for general information only. It is not a diagnosis, treatment plan, or substitute for advice from a registered dentist or orthodontist. ### Compare next steps [Orthodontist Near Me](https://virtualconsultant.online/locations/orthodontic-treatment-near-me) [Clear Aligners Near Me](https://virtualconsultant.online/treatments/clear-aligners-near-me) [Invisalign Near Me](https://virtualconsultant.online/locations/invisalign-provider-near-me) [Browse Locations](https://virtualconsultant.online/locations) ### Ready for a clearer starting point? Upload guided photos and receive an indication of likely treatment options and pricing before booking appointments. [Get an Online Quote](https://virtualconsultant.online/evaluations/quote) ### Frequently Asked Questions Is CBCT always better than an OPG for orthodontics? No. CBCT provides three-dimensional information that 2D radiographs cannot, but it delivers a higher radiation dose and should only be used when the specific clinical question cannot be answered by an OPG or other 2D image. For routine orthodontic assessment — tooth number, eruption status, root lengths, jaw anatomy — an OPG is appropriate. CBCT is justified for impacted teeth with uncertain root proximity, root resorption assessment, airway analysis, and surgical planning where 3D anatomy is critical to safe treatment. Do all patients getting braces need X-rays? Most patients starting a comprehensive course of orthodontic treatment need at minimum an OPG and often a lateral ceph, as these images provide clinical information that cannot be gathered from examination alone and that directly affects treatment planning decisions. Not every patient needs a CBCT or full series of periapicals. The radiographs taken should be those clinically justified by the findings on examination. If you are having a limited or cosmetic course of treatment where records are less complex, fewer images may be appropriate. Can I refuse an orthodontic X-ray? You have the right to ask why an X-ray has been recommended, what clinical information it will provide, and whether the treatment can proceed safely without it. For some treatment decisions — such as extractions, impacted tooth management, or jaw surgery planning — proceeding without the required radiographic information would be clinically unsafe and your clinician may not be able to continue with the planned treatment. For straightforward alignment cases, there may be more flexibility. Raising concerns with your clinician is always appropriate; they should be able to explain the justification for any imaging they recommend. What is the radiation dose from a dental panoramic X-ray? A modern digital OPG delivers approximately 2 to 4 microsieverts, which is equivalent to a few hours of natural background radiation or less than one day of the UK annual average background dose of approximately 2,700 microsieverts. This is extremely low and the risk to health from a single OPG is negligible. The dose is substantially lower than from older film-based systems. Including a lateral cephalogram adds approximately another 3 to 6 microsieverts, meaning a standard orthodontic records set is well within acceptable limits. When is CBCT justified for an impacted tooth? CBCT is clinically justified for an impacted tooth when a 2D OPG or periapical radiograph cannot clearly show the tooth's position relative to adjacent root surfaces, the degree of root resorption present, or the relationship to critical anatomical structures. This is most commonly relevant for palatally impacted upper canines in proximity to the roots of the lateral incisor or central incisor, where the three-dimensional position determines the risk of root resorption during surgical exposure. If the OPG clearly shows an uncomplicated labial canine position with no root proximity concerns, a CBCT is not required. Why does my orthodontist need a lateral ceph? A lateral cephalometric radiograph allows precise measurement of the skeletal jaw relationship and incisor inclinations — information that cannot be reliably estimated from clinical examination alone. It determines whether a bite problem is dental (teeth position) or skeletal (jaw bone relationship), which directly affects whether braces alone can achieve the desired result or whether jaw surgery is needed. It is particularly important for extraction planning, overjet or underbite cases, jaw surgery assessment, and growth modification with functional appliances. Some straightforward cosmetic alignment cases may not require a lateral ceph, but for any case with a bite discrepancy it provides essential planning information. How often do I need X-rays during orthodontic treatment? Routine interval radiographs during fixed brace treatment are not recommended unless there is a specific clinical indication — for example, monitoring root resorption in a susceptible patient, assessing the eruption of an impacted tooth that is being surgically exposed, or evaluating a tooth that has been causing unexplained symptoms. UK and European guidelines (FGDP radiography guidelines 2020) advise against taking radiographs at fixed time intervals without clinical justification. Your orthodontist should explain the reason for any radiograph taken during treatment. Explore your options Quick links Not sure where to start? Use these quick links to explore orthodontic treatments, typical costs, and helpful guides that explain what different options involve. Whether you're researching braces or clear aligners, comparing pricing, or just getting a feel for what comes next, you can browse at your own pace and come back when you're ready to request a quote. Explore [Get Quote](https://virtualconsultant.online/evaluations/quote) [Costs](https://virtualconsultant.online/costs) [Browse Treatments](https://virtualconsultant.online/treatments) [Teeth Straightening](https://virtualconsultant.online/treatments/teeth-straightening) [Browse Problems](https://virtualconsultant.online/problems) [Locations](https://virtualconsultant.online/locations) [Near Me](https://virtualconsultant.online/locations/orthodontic-treatment-near-me) [NHS Eligibility Checker](https://virtualconsultant.online/about/do-i-qualify-for-nhs-treatment) [IOTN Score Checker](https://virtualconsultant.online/about/iotn-score-checker) [How To Take Orthodontic Photos](https://virtualconsultant.online/about/process/how-to-take-orthodontic-photos) [Online Orthodontist](https://virtualconsultant.online/guides/online-orthodontist-uk) [Research Papers](https://virtualconsultant.online/research) [Social Channels](https://virtualconsultant.online/social) ## Ready for a personalised answer? Upload guided photos and get a tailored recommendation for your teeth and bite. [Start Photo Assessment](https://virtualconsultant.online/evaluations/quote) [Find an Orthodontist](https://virtualconsultant.online/locations) Citation details Title CBCT vs OPG X-ray UK | Orthodontic Scan Comparison Publisher Virtual Consultant Online Published 2024-06-01 Updated 2026-08-27 URL [https://staging.virtualconsultant.online/guides/cbct-vs-opg-xray-uk](https://staging.virtualconsultant.online/guides/cbct-vs-opg-xray-uk)