CHAPTER 6
Imaging
6.1 INTRODUCTION
The prescription of radiographs for a patient for whom dental implants are planned must be based on a comprehensive history and oral examination. Indeed, the prescription of radiographs to assess implant sites should not be undertaken in isolation, but rather form part of an appropriate and overall radiographic assessment. Where a patient has been referred from another practitioner, sight of existing radiographs may be required to make a full assessment of the patient’s oral status and their suitability for dental implant placement. The Selection Criteria in Dental Radiography, published by the Faculty of General Dental Practitioners UK (FGDP(UK)), presents guidelines on radiographic assessment for the new adult patient [1].
The specific requirements for imaging prior to dental implant placement are set out in the 2011 European Association of Osseointegration (EAO) guidelines for the use of diagnostic imaging in implant dentistry as follows:
‘In investigating a patient for implant treatment, a clinician requires information on bone volume, structure and density, topography, and the relationship to important anatomical structures, such as nerves, vessels, roots, nasal floor, and sinus cavities and any clinically relevant pathology’. [2]
The Selection Criteria in Dental Radiography further states that:
‘Successful implant placement is facilitated by the availability of adequate information about the quantity and quality of bone at the proposed implant site in relation to the position and design of the planned prosthesis’. [3]
6.2 IMAGING IN TREATMENT PLANNING
Image prescription should always follow a thorough history and examination [4]. It is not acceptable to prescribe ‘standard’ imaging for all patients for whom dental implants are considered. Instead, an individual prescription should be made for each patient (B).
| Aspirational | Basic | Conditional |
|---|---|---|
| An individual prescription should be made for each patient based on their individual requirements. (i) | A radiographic assessment must be undertaken prior to implant placement. (i) | If cross‐sectional imaging will improve the outcome for the patient and surgeon then it should be used. (i) |
| If measurements are to be taken from a two‐dimensional image, magnification markers should be used. (i) | The ALARA principle should be followed. Radiographs should be justified and reported. (i) |
Information should first be obtained with conventional radiography. From the history, examination and conventional radiographs, the decision can be made to prescribe cross‐sectional imaging. The EAO guidelines state that ‘The decision to proceed to cross sectional imaging should be based on clearly identified needs and the clinical and surgical requirements of the clinicians involved’ [2] (B).
Every exposure to ionising radiation carries a risk. Whilst this is generally very low in dentistry, the benefits of every exposure to a patient should outweigh the risks, therefore every exposure should be justified on this basis. Once a view has been justified, the radiographic procedure should be optimised. In general, the ALARA principle should be followed, which states that the dose should be kept as low as reasonably achievable [5] (B). Factors such as equipment selection, exposure settings, collimation and quality controls are relevant. The technique should provide the required diagnostic information consistent with the least exposure of the patient to ionising radiation (B).
The range of available imaging techniques prior to dental implant placement is listed in both the FGDP(UK)’s Selection Criteria in Dental Radiography and the EAO guidelines [2, 6].
6.2.1 Conventional Techniques
- Periapical radiography: This technique has the limitation of producing a two‐dimensional image but this often the radiograph of choice for uncomplicated single sites.
- Panoramic radiography: This technique has the limitation of providing only a two‐dimensional view but it provides general information about bone height and the position of anatomical structures.
- Lateral cephalometric radiography and the transymphyseal technique [7]: These techniques may be useful to give a cross‐sectional view of the edentulous anterior mandible.
6.2.2 Sectional or Three‐dimensional Imaging Techniques
- Conventional cross‐sectional tomography: This demanding and time‐consuming technique has been largely replaced by more modern sectional imaging techniques, such as cone beam computed tomography (CBCT), and may be considered obsolete.
- Multi slice medical CT
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