Dentists rely heavily on X-rays to diagnose hidden dental problems. Dental cavities, gum disease, infections, and many other oral lesions can only be detected in their early stages by taking proper radiographs. Without X-rays, your dentist won't be able to diagnose cavities until they cause pain. Early-stage gum disease can be detected by looking at X-rays of your teeth. Some oral infections don't manifest any symptoms and can only be diagnosed through X-rays. Dentists also use X-rays to communicate with specialists, insurance companies, and other dental providers. Taking X-rays is an essential part of dentistry, which is why most dental visits start off by taking X-rays of your teeth.
There are about three to four common types of X-rays used in dentistry. Dentists use different X-rays for different reasons. Some X-rays are used to diagnose dental cavities and gum disease. Some X-rays are used to visualize nerve canals and sinus membranes. Others X-rays are used for orthodontic diagnosis. Here are the most common types of X-rays used to diagnose various oral conditions:
- Periapical X-rays & bitewing X-rays
- Panoramic radiograph
- Lateral cephalometric
- CT/CBCT scan
Periapical and bitewing X-rays are those little X-rays that the dental assistant takes while you sit in the dental chair. Open, close, bzzzz! Periapical and bitewing X-rays capture lots of fine details on your teeth. Therefore, they are ideal X-rays for diagnosing dental cavities, tooth infections, and even gum disease. Most periapical and bitewing X-rays cover three, four, or maybe five teeth. You need about a dozen or so X-rays to capture the whole mouth. Most dentists typically take anywhere from 12 to 14 periapical X-rays as well as 4 bitewing X-rays on your initial visit. This is referred to as full mouth X-ray series. These X-rays provide your dentist with a full view of what your teeth and jawbone look like. These X-rays are followed by an additional 6 to 8 radiographs on future recall appointments. Recall X-rays are used to diagnose new issues that your teeth may be facing.
Panoramic radiographs are used to visualize wisdom teeth, impacted teeth, sinuses, as well as major nerves and arteries. They also assist with diagnosing Temporomandibular Joint (TM) problems. These X-rays capture a large segment of your skull. They provide your dentist with a broad overview of what your teeth, jaws, and facial bones look like. Panoramic X-rays are useful for oral surgery procedures like tooth extraction and dental implant placement. However, they are not useful for diagnosing dental cavities. While very useful for many procedures, Panoramic X-rays are not a substitute to traditional radiographs for diagnosing cavities.
Lateral cephalometric X-rays are primarily used for orthodontic diagnosis. These X-rays show the relationship between your upper and lower teeth and jawbone from a lateral perspective. Orthodontists use lateral cephalometric X-rays to identify your jaw relationship and monitor your braces treatment. Lateral Cephalometric X-rays can also be used for the diagnosing obstructive sleep apnea (OSA) and certain ENT conditions.
CT scans and CBCT scans capture 3-D images of your facial structures. CT scans are used to capture a 3-D image of the whole jaw. CBCT scans can only capture a small region and not the entire skull. Because CT scans and CBCT scans are 3-D images, they capture details that go undiagnosed on regular X-rays. The main use of CT and CBCT images is to identify important landmarks during dental implant surgery. These X-rays are used to measure bone width, identify nerve location, and measure the jawbone under your sinus membranes. In fact, a CT or CBCT scan is the only acceptable diagnostic radiograph for treatment planning implant dentistry.
It all depends on which dental treatment you need. Periapical X-rays and bitewing X-rays are the most commonly used types of dental X-rays. If you need a couple of cavities fixed or dental cleaning, then you probably need to take a few bitewing and periapical X-rays. If you need your wisdom tooth removed then you need a panoramic X-ray, possibly a CT scan. Braces treatment for overbites and underbites may require a lateral cephalometric X-ray. Dental implants usually require a CT or CBCT scan and other necessary radiographs. Discuss your issues with your dentist to determine which X-rays are the most appropriate for your diagnosis.