SELECTION AND USE HOW MANY?

The extremely low radiation dosage employed in dental radiography, especially when com-bined with collimation and protective leaded drapes and collars, provides a high degree of

Fig 3.8

Radio-opaque die injected into the joint space helps de-fine soft tissue joint components in this temporomandibu-lar joint arthrogram.

Fig 3.9

Magnetic resonance imaging of the joint and fossa region,

Fig 3.10

(a) Oblique extraoral view of mandible, (b) Lateral skull projection, suitable for cephalometric analysis.

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Fig 3.11 Current guidelines for ‘How often?’. (This chart has been adapted and reprinted with permission from Eastman Kodak Company.) ADA—American Dental Association AGD—Academy of General Dentistry AAOMR—American Academy of Oral and Maxillofacial Radiology AAOM—American Academy of Oral Medicine AAPD—American Academy of Pediatric Dentistry AAP—American Academy of Periodontology FDA—United States Food and Drug Administration

STRATEGIES IN DENTAL DIAGNOSIS AND TREATMENT PLANNING 38

safety and confidence. The dentist may have to educate patients in this area. The most common radiographs used in dentistry are also very cost-efficient. Therefore, the answer to ‘how many?’

is ‘enough,’ that is, we must obtain a sufficient number of good quality radiographs to make accurate diagnoses. This is a professional, ethi-cal, and legal standard of care. On the other hand, we must also take care not to take more radiographs than are needed simply to fill up slots on the mount. Radiographs should always be based on diagnostic need, rather than any routine protocol.

Example 1. An 18-year-old male patient is seen as an emergency after a blow to the chin (sports accident). There is swelling and bruising on lip and chin, and two lower incisors are very loose. What radiographs are indicated?

Answer. As this is an emergency and not a fully comprehensive examina-tion, only the areas of immediate concern need to be imaged. This would include PA views of the loosened anterior teeth, and panoramic or other extraoral im-ages of the mandible to diagnose or rule out fracture either at the site of the trauma or elsewhere within the mandible. The condyles need to be imaged, be-cause the neck region is the thin-nest portion of the bone, and most at risk of fracture.

Example 2. A 57-year-old new female patient (missing all bicuspids and molars) needs general dental care, includ-ing upper and lower distal exten-sion partial dentures. What radio-graphs are indicated?

Answer. A combination of panoramic film and anterior PAs to image the teeth and surrounding bone will provide good coverage. As an alternative to the panoramic film, holding de-vices of various types can be used to image posterior edentulous ar-eas.

Example 3. A 34-year-old fully dentulous male with numerous visible carious le-sions and fractured teeth is seen for

a new patient examination. He re-calls having bite wing radiographs a year or so ago. What radiographs are indicated?

Answer. The presence of active dental dis-ease calls for current and accurate diagnostic data. A full mouth series, including periapicals of all teeth and double bite wings, is indicated.

HOW OFTEN?

Frequency is another issue involving both cost and exposure. Here again routine protocols (bite wings every 6 months) based solely on time interval are not acceptable. Current guide-lines, developed by a panel of experts repre-senting the ADA, AGD, AAOMR, AAOM, AAPD, AAP, under the sponsorship of the FDA are outlined in Fig 3.11.

Example 1. A 12-year-old boy with eight proxi-mal carious lesions visible on ra-diograph will be placed on 6-month recalls for examination, cleaning, and fluoride. When would you next take bite wing ra-diographs?

Answer. As a result of the high caries rate and likelihood of undetectable in-cipient caries, follow-up bite wings at the 6-month recall are indicated.

Based on findings at that time, con-tinued monitoring at 6–12 month intervals may be indicated.

Example 2. A 40-year-old new female patient has no pathology or abnormality visible in full-mouth radiographs.

No dental treatment is needed, other than routine cleaning. When would you next take a full series of radiographs?

Answer. Assuming that regular check-ups reveal no pathology, and no symp-toms arise, this patient could eas-ily go 3–5 years or more before an-other full series is taken.

Example 3. A pregnant 24-year-old female pa-tient is seen on emergency with an acute dental abscess. She agrees to endodontic therapy, and two

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tional appoint-ments are scheduled.

What radiographs would you take?

Answer. Using appropriate shielding, there is no contraindication to dental ra-diographs in pregnancy. This clini-cal situation clini-calls for periapiclini-cal di-agnostic and measurement films appropriate to endodontic therapy.

Sensitivity to patient concerns and careful education may be required to allay fears.

The general operative principle in the selec-tion and use of dental radiographs is to ob-tain whatever films are necessary for diagno-sis and treatment planning condiagno-sistent with radiation safety and cost-effectiveness. All dental radiographs must meet minimum standards for quality, that is, they must be ‘di-agnostic’ films, properly aligned, exposed, and processed.

Inadequate radiographs can seriously com-promise dental and oral diagnosis, and lead to

inappropriate or untimely treatment. The reader is encouraged to consult the many ex-cellent reference works for specific details re-garding dental radiography.

Digital radiography, employing a radiation-sensitive receiver in place of the X-ray film, can produce digital images on a computer monitor almost instantaneously. It has the advantage of lower radiation exposure as a result of the great sensitivity of the receiver, and having images available immediately is a great convenience and time saver. Applications in endodontic treatment and surgery, especially for measure-ment and assessmeasure-ment of work in progress, are obvious. Drawbacks at this time include the high cost of the technology, difficulty in archi-val storage which requires considerable com-puter capacity, and problems from the medi-colegal standpoint. As digital images can be altered without a trace, their use as evidence can be questioned. These problems may well be addressed with advances in technology in years to come.

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