Diagnostic radiography is an integral part of the clinical process. It is predicated on a careful correlation of patient history and clinical findings. Radiographs should be ordered in those instances in which the clinician anticipates that the expected information obtained will contribute materially to the proper diagnosis, treatment, and prevention of disease. Consequently, the clinician’s responsibility in obtaining radiographs involves two major considerations: (1) the clinical decision to order radiographic studies, and (2) the selection of an appropriate number and type of radiographic views necessary to conduct the examination.
|Why are the radiographs necessary?|
|What alternate diagnostic aids are available?|
|What risks are inherent in the use of ionizing radiation?|
|What radiation protection measures will be taken?|
|What effect the lack of quality dental radiographs may have on the diagnosis, treatment, and prognosis?|
In order to maximize diagnostic yield yet minimize the risk of unnecessary exposure, clinicians are responsible for assuring that all radiographs are obtained in accordance with the current standard of care. The type of radiographs, the number of films taken, the date on which they were taken, and the diagnostic data obtained should be documented in the progress notes. Furthermore, since radiographs often represent the only evidence of past dental treatment or disease and serve as the basis for future treatment decisions, they must be retained as part of the patient’s permanent record.
Before initiating any radiographic procedures, the clinician is further responsible for obtaining the patient’s consent. The consent given by the patient may be implied or expressed. An implied consent is sufficient for commonly performed procedures that have few known risks. When a procedure has perceived or potential risks associated with it, such as the use of ionizing radiation on a child or a pregnant woman, the clinician should receive the guardian’s or the pregnant patient’s expressed consent (Table 6.1).
Open contacts in the primary dentition will often allow the clinician to visually inspect the proximal surfaces of posterior teeth. However, closure of contacts may potentially lead to the development of proximal carious lesions. Therefore, posterior bitewing radiographs are recommended for new patients with primary dentition where the proximal surfaces are not easily visualized or explored.
The incidence of dental caries tends to increase in children with a transitional or mixed dentition as a result of socialization, dietary modifications, and changes in daily oral hygiene procedures. Posterior bitewing radiographs are recommended for new patients with a transitional dentition for the detection of caries. This survey may be augmented with selected periapical views when clinical evidence suggests the presence of an apical pathosis or periodontal disease (rare). Periapical/occlusal views may be appropriate to assess the presence/absence and growth/ development of all permanent teeth. A panoramic view with posterior bitewing radiographs is an acceptable alternative.
Increased independence and socialization, changing dietary patterns, and decreased attention to daily oral hygiene characterize this age group. Each of these factors may result in an increased risk for dental caries. Although proximal surfaces continue to show caries development, there is a tendency for caries activity to shift from proximal surfaces to surfaces with pits and fissures. An individualized radiographic examination should consist of posterior bitewing radiographs and selected periapical views. A panoramic view may facilitate the assessment of the presence, position, and stage of development of third molars.
Although the incidence of proximal caries in the adult patient population is declining, it is important to assess proximal surfaces in new adult patients for primary and recurrent disease activity (the incidence of root surface caries increases with age, but the usual method of detecting such lesions is by clinical examination). In addition, adult patients may have signs and symptoms of periodontal and/or pulpal disease, or have missing teeth requiring replacement. Therefore, adult dentate patients should have posterior bite-wing radiographs and selected periapical films. Routine full mouth radiographs are not indicated unless the patient presents with clinical evidence of generalized dental disease or evidence of extensive past dental care.
Radiographic examination for occult disease in this patient population cannot be justified on the basis of disease prevalence, morbidity, mortality, radiation dose, and cost. However, a full mouth series of periapical radiographs or a panoramic view of the edentulous patient in conjunction with anticipated prosthetic reconstruction is appropriate to assess the presence or absence of impacted teeth, retained roots, bony spicules, residual cysts or infections, developmental abnormalities of the jaws, intrabony tumors, and systemic conditions affecting bone metabolism. In addition, diagnostic imaging provides information on the anatomical location of the mandibular canal, the position of the mental foramen and maxillary sinus, and the relative thickness of soft tissues covering the alveolar ridges.
In spite of the general decline in the incidence of dental caries, subgroups of children have a higher caries experience than the general population. The identification of patients in these subgroups may be difficult on an individual basis. Consequently, children with primary dentition with closed posterior contacts that show no clinical caries and that are not at risk for the development of caries benefit from an examination consisting of posterior bitewing radiographs, performed at intervals of 12–24 months. This recommendation is based on evidence that dental caries progress more rapidly in primary teeth (thinner enamel with higher organic components) than in permanent teeth.
The incidence of dental caries generally increases during the transitional period. In addition, the enamel of permanent teeth undergoing posteruptive maturation may facilitate faster progression of carious lesions. Therefore, children with a transitional dentition who show no clinical caries and are not at risk for the development of caries benefit from an examination, consisting of posterior bitewing radiographs, performed at intervals of 12–24 months.
The caries process in the permanent dentition takes about 36 months to progress from initial involvement of the enamel surface to the dentin. Consequently, it is recommended that in adolescents who show no clinical caries and are not at high risk for the development of caries, an examination consisting of posterior bitewing radiographs be performed at intervals of 18/>