Table 2.

Overview of key findings for different radiographic techniques, including advantages, disadvantages and their usefulness in caries detection and diagnosis for the different sites at which caries might occur. Caries on the buccal and lingual surfaces of teeth are completely accessible to visual examination, so radiography would normally have no role to play. The table is based on both scientific evidence and expert opinion

Radiographic technique	Advantages	Disadvantages	Caries Diagnosis Applicability
Bitewing radiography	Correct geometry allows for: • Optimal geometry for proximal tooth surface assessment • Optimal geometry for alveolar bone level assessment • Maxillary and mandibular teeth captured in one image • High image resolution (high image detail) • Relatively low radiation dose (1–5 µSievert) • Low economic costs	• Not always comfortable for every patient • Not easy to position a holder if opposing teeth are missing (geometry may be compromised) • In case of dental crowding interproximal dental surfaces cannot always be visualised (overlapping projections) • More than one image sometimes needed per side in a fully dentate patient. • Only two-dimensional	Occlusal caries  • No diagnostic value for enamel-only lesions  • Moderate sensitivity and high specificity for dentine lesions  • Has value for dentine lesions which, on visual examination, show initial enamel demineralisation. Proximal caries  • Low to moderate sensitivity and high specificity for early lesions  • low risk of false positive diagnoses  • Higher sensitivity for deeper lesions Root surface caries  • Low level of evidence available for diagnostic accuracy  • Risk of misinterpreting “cervical burn-out” for caries and vice versa Recurrent caries  • Moderate sensitivity with relatively high specificity, with greater value for proximal surfaces.  • Risk of interpreting residual caries, deliberately left in deep cavities, as recurrent caries.  • Risk of interpreting restoration deficiencies as recurrent caries.
Periapical radiography	Correct geometry allows for: • convenient interproximal tooth surface assessment • alveolar bone level assessment • relatively low radiation dose (1–5 µ Sievert) • Low economic costs	• Not always comfortable for every patient • might not have ideal vertical X-ray beam angulation for caries detection • Not easy to position a holder if opposing teeth are missing (geometry may be compromised) • In case of dental crowding, interproximal dental surfaces cannot always be visualised (overlapping contact points) • Multiple radiographs needed to image all the teeth in most patients • Only two-dimensional	Limited evidence on periapical radiography, as research is overwhelmingly on bitewings, but diagnostic accuracy is likely to be similar assuming paralleling technique is used. Any vertical angulation on the radiograph, relative to a bitewing, is likely to reduce diagnostic accuracy. Occlusal caries  • As for bitewing radiography if image geometry is ideal Proximal caries  • As for bitewing radiography if image geometry is ideal Root surface caries  • As for bitewing radiography if image geometry is ideal Recurrent caries  • As for bitewing radiography if image geometry is ideal  • Vertical X-ray beam angulations might conceal lesions below restorations.
Panoramic radiography	• If patient is positioned according to manufacturer’s guidelines, a diagnostic overview of both maxilla and mandible is produced with minimal interproximal overlap between teeth • relatively low radiation dose (on average 24 µSievert) • Moderate economic costs	• If patient is not positioned according to manufacturer’s guidelines, an inferior quality overview of both maxilla and mandible is produced with often enormous interproximal overlap of teeth • Secondary “ghost” images may compromise interpretation • Lower image resolution than intraoral radiography • Good patient cooperation needed in view of extended exposure time • Lower image resolution than intraoral radiography • Only two-dimensional	No systematic review evidence. Most diagnostic accuracy research is old and lacks relevance to modern panoramic X-ray systems Occlusal caries  • Has some diagnostic value for dentinal lesions Proximal caries  • Lower sensitivity likely due to overlap of contact points and/or overlying soft tissue and air  • Lower specificity possible due to overlying radiolucency from air in the oral cavity Root surface caries  • As for proximal caries, although overlap of roots of adjacent teeth less likely. Recurrent caries  • Likely to be similar to bitewing radiography, although diagnostic accuracy might be reduced by lower image resolution
Modified panoramic radiography – “extraoral bitewing”	• If patient is positioned according to manufacturer’s guidelines a periapical view of both maxillary and mandibular posterior teeth is produced with minimal interproximal overlap between teeth • Useful for patients who cannot tolerate intraoral radiography • relatively low radiation dose (approximately 15 µSievert) • Moderate economic costs	• If patient is not positioned according to manufacturer’s guidelines, an inferior quality overview of both maxilla and mandible is produced with often enormous interproximal overlap between teeth • Ghost images may compromise interpretation • Lower image resolution than intraoral radiography • Good patient cooperation needed in view of extended exposure time • Lower image resolution than intraoral radiography • Only two-dimensional	No systematic review evidence. Very limited primary research studies. Occlusal caries  • As for conventional panoramic radiography. Deep lesions can be well demonstrated. Proximal caries  • Assuming fewer overlapping contact points, sensitivity is similar to that with conventional bitewing radiography Root surface caries  • As for conventional panoramic radiography Recurrent caries  • As for conventional panoramic radiography
Cone beam computed tomography (CBCT)	• “Three dimensional” imaging of teeth is provided by multiplanar reformatting • Might assist in assessment of cavitation of proximal caries	• Streaking and beam hardening artefacts may compromise interpretation, leading to false positive diagnoses • Lower image resolution than intraoral or panoramic radiography • Motion artefacts common due to long scanning times radiation dose relatively high, varying with field of view, resolution and mA settings (10-1100 µSievert) • High economic costs	Current evidence and guidelines suggest CBCT should not normally be used specifically for caries diagnosis, but that scans taken for other reasons should be examined for dental caries. For all caries types, detection can be substantially reduced if artefact from metal (e.g. crowns, implants) is present Occlusal caries  • Higher sensitivity than radiography in the absence of restorations but lower specificity Proximal caries  • Higher sensitivity and similar specificity to radiography in the absence of restorations  • Might be able to detect cavitation Root surface caries  • No systematic review evidence for diagnostic accuracy  • Most likely, better diagnostic accuracy than for radiography Recurrent caries  • No systematic review evidence for diagnostic accuracy.  • Likely reduction of sensitivity and specificity