Bitewing radiograph

A bitewing radiograph is the intraoral posterior view that shows the anatomical crowns and the interproximal alveolar bone level in a single image. Current ADA and AAOMR guidance makes it the indicated radiograph for posterior proximal caries you can't see clinically. For root morphology and periapical lesions, the same guidance names the periapical radiograph instead.

Synonyms: bitewing; bite-wing radiograph; bitewing X-ray; interproximal radiograph

What does a bitewing show that other views don't?

Two things in the same image: the proximal surfaces of the posterior teeth, and the bone crest between them.

Horizontal bitewings are reliable for proximal caries and for the interproximal alveolar bone level [3]. In a retrospective review of 320 dental-school records of patients already showing posterior bone loss, a greater number of horizontal bitewings showed the entire anatomical crown than vertical ones did [4].

The guidance is narrower than "it finds cavities", and the narrowness is the useful part. For posterior proximal caries that isn't clinically visible, bitewings are indicated [1]. For anterior proximal caries that isn't clinically visible, periapical radiographs are [1]. The bitewing's answer set is posterior, and it starts where your eyes and probe stop. For occlusal caries and for root caries, the guidance is softer: periapical or bitewing radiographs may be indicated [1].

The crestal bone is the second half of the answer set and it's the half that gets forgotten. One study of 21 patients with periodontitis found bitewing radiography the most accurate of the radiographic methods it compared for assessing crestal bone level, with periapical radiography the least accurate; the authors concluded that both bitewing and panoramic radiography are preferred to periapical images for crestal bone assessment [8].

None of this is new. When radiography is applied in the clinic for caries detection, the recommended technique is the bitewing projection — a technique Wenzel's review traces to Raper in 1925, continued since with only minor alterations [6]. What has changed is what else is available, and the guidance is explicit that CBCT is not indicated for caries detection [1].

What can't a bitewing show?

Start with the apex, because it's the question beginners bring to the wrong view. To assess root morphology, root blunting or resorption, and periapical lesions, the periapical is the view the guidance names as most appropriate [1].

Four more limits worth holding:

Root surface caries. Bitewings can assist in detecting it in proximal areas, but the usual method of detecting root surface caries is clinical examination [2].

Whether periodontal disease is active. Radiographic evidence of the presence and severity of periodontal bone loss does not indicate active disease [1]. The radiolucent crest tells you where the bone is, not what it's doing.

The extent of bone loss, and furcations. On a horizontal bitewing, interproximal root caries, horizontal and vertical alveolar bone loss, and furcation involvement are all difficult to detect [3]. In one randomised cross-over trial of 20 patients, furcation areas in molars were detected on 100% of vertical bitewings against 57.5% of horizontal ones [3]. The same review of 320 dental-school records found vertical bitewings showed the level of alveolar bone loss in 52.81% of cases against 3.75% for horizontal bitewings, and the furcations in 43.44% against 1.25% [4]. Two studies, two sets of criteria — but the direction is the same, and it is not subtle.

A restoration margin, reliably. In a systematic review, visual, radiographic and laser fluorescence detection of secondary caries had similar sensitivities of 0.50 to 0.59 and specificities of 0.78 to 0.83. Most of the pooled studies were performed in vitro on permanent posterior teeth, and the review reports that most had high risk of bias or applicability concerns [5]. Treat a clean margin on a radiograph as weak evidence, not as an answer.

What it's confused with

When is a bitewing the right view to take?

The decision runs in one order, and the radiograph is not first. A thorough evaluation of the patient history and clinical findings should precede radiographic examination [1], and radiographic screening for the purpose of detecting disease before clinical examination should not be performed [2].

Once you've looked, the indications are specific:

• Posterior proximal caries that isn't clinically visible — bitewings are indicated [1].
• Depth estimation of proximal caries on surfaces you can see — periapical or bitewing radiographs may be indicated [1]. That's where radiographic depth classification does its work, and where how early a proximal lesion becomes visible starts to matter.
• Occlusal caries, and root caries — periapical or bitewing may be indicated [1].
• A patient with a history of, or with active, periodontal disease — vertical bitewings are recommended to assess bone levels in the permanent dentition [1]. For evaluating periodontal structures after a comprehensive clinical examination, a 2D full-mouth series including vertical bitewings as necessary is recommended [1].
• Anterior proximal caries that isn't clinically visible — take a periapical, not a bitewing [1].

At a recall visit for a patient with periodontal disease, the guidance defers to you: clinical judgment as to the need for and type of images, which may consist of, but is not limited to, selected bitewing or periapical images of areas where periodontal disease other than nonspecific gingivitis can be found clinically [1].

How often should bitewings be repeated?

By risk and dentition, not by calendar. The current ADA and AAOMR recommendations set posterior bitewing recall intervals as follows [1]:

The frequency of radiographic recall should be determined on the basis of caries risk assessment, and a patient's caries risk status may change over time, so an individual's radiographic recall interval may need to change with it [1][2].

The 2012 ADA and FDA recommendations explain that time-based schedules were adopted because attempts to identify criteria that would accurately predict a high probability of finding interproximal carious lesions have not been successful for individuals; each schedule's range derives from research into the rate at which interproximal caries progresses through enamel, and professional judgment determines the optimum time within the suggested interval [2].

One caution about all of the above: it is national guidance, not a universal rule. The 2026 ADA and AAOMR recommendations are a US document, published as an update to the 2012 ADA and FDA recommendations [1]. UK practice works to the College of General Dentistry's Selection Criteria for Dental Radiography, now in its third edition, which the Care Quality Commission expects dental practices in England to comply with [7]. Read the guidance that applies where you're registered.

Common errors

Bringing the wrong question. Root morphology, root blunting or resorption, a suspected periapical lesion — those are periapical questions [1]. A bitewing will not refuse to be read; it will just not answer.

Turning the interval into a calendar. The interval follows caries risk assessment, and risk changes [1][2]. "Bitewings every two years" is a habit, not a recommendation.

Reading bone level as disease activity. The radiograph shows presence and severity of bone loss, which does not indicate active disease [1].

Expecting a horizontal projection to stage periodontal bone loss. It largely doesn't [3][4]. If bone loss is the question, the vertical projection is what the guidance recommends [1].

Overlapping the contacts and reading on anyway. See overlapped contacts, and the order you read a bitewing in.