Dental Radiographyexamination plays a vital role in the diagnosis and treatment planning of both children and adults. It has to be stressed that radio-graphs have an additional importance in the evaluation and treatment planning of pediatric dental patients.
A complete dental radiography examination of the dentition and associated structures should include a radio graphic survey as well In pediatric dental practice. Dental Radiography also play a significant role in the assessment of growth and development.
Dental Radiography, at the simplest level, help in the detection of dental caries and at the most complex level in the diagnosis of cysts, tumors or any other major craniofacial disorders.
The work of many scientists culminated in the discovery of X-rays by Roentgen on November 8. 1895. The then unknown and invisible rays were given the name X-rays by Roentgen because of the simple fact that the nature of these rays were not known at the time of the discovery.
However discovery of X-rays changed the medical science rapidly, bringing in a great revolution. X-rays have also been widely used in dentistry and have a special place in pediatric dentistry where the growing child with a developing dentition needs to be assessed carefully.
Types of Dental Radiography
The radiographs taken of a child patient can be broadly grouped into two categories: intra-oral and extra-oral radiographs.
Accordingly, the film used in pediatric dental practice for dental radiography examination can be grouped into:
1. Intra-oral films
2. Extra-oral films
Intra—oral films are meant for positioning inside the mouth during exposure. There are three types of intraoral dental radiography projections:
- lntraoral periapical (IOPA) radiographs
- Bitewing radiographs
- Occlusal radiographs
- Size 0 is used for bitewing and periapical radio graphs of small children.
- Size 1 is used for radiographing the anterior teeth in adults. This film is not routinely used.
- Size 2 is the standard film used for anterior occlusal radiograph, periapical radiograph and bitewing survey in mixed and permanent dentition.
Occlusal films have a size of 57 x 76 mm and are taken for visualizing the entire maxillary or mandibular arches.
Extra oral films
Most of the extra-oral films are used in intensifying screen-film combination. The extra-oral films used in dental radiography vary in their sizes depending on the individual projection for which they are employed.
- 1.5 x 7 inches films – these films are used for temporomandibular joint (TMJ) views and lateral oblique views.
- 8 x 10 inches films: These films are used for lateral cephalograms, paranasal sinus view, etc.
- 6 x 12 inches film: These films are used for orthopautoniography.
Composition of films
A dental radiography film is an image receptor system. On exposure to x-rays, there is formation of an invisible image or latent image which when chemical processed transforms into a visible image which can be viewed under trans—illumination.
An X-ray film consists of the following components:
1. Base: The base of x-ray film is made up of a polyester, polyethylene terepthalate. The base helps in supporting the emulsion which gets chemically activated when exposed to x-rays. The base also provides rigidity to the film.
2. Adhesive layer: An adhesive layer is present over the base to attach the film emulsion to the film base.
3. Film emulsion: The film emulsion is the main image receptor system of x-ray film, as this is sensitive to both light and x—rays. The emulsion mainly consists of silver bromide crystals with some amount of silver iodide.
As it has already been mentioned, when the film is exposed to x-rays, a latent image is formed in the film which gets converted to a visible image only when chemically processed.
For dental radiography to be of proper diagnostic quality, it should be free from technical or processing errors and it should give sufficient information pertaining to the area radio graphed or for which purpose the dental radiography projection is made.
Visualization of dental radiography
Visualization of a radiograph requires a good source of extraneous light. A thorough knowledge of the basic anatomy and the radiographic appearance of various osseous structures is very essential in the proper interpretation of radiographs. Radiographs should be examined in a quiet area that is free from multiple extraneous stimuli.
Conditions and Areas routinely Evaluated
- The degree and variation of calcification of the teeth. and the size, shape, position and angulation of the unerupted teeth:
- The presence or absence of teeth, including anomalies in number, delayed eruption, or impaction.
- Carious lesions and interproximal carious lesions in particular. Incipient lesions on the facial and lingual surfaces are not seen in a radiograph and are more readily found with an explorer. Dental radiography evidence of caries is seen only when substantial amounts of decalcification has occurred and a change in density is noted.
- Degree and variation of root resorption of the primary teeth, as well as the root development of the permanent teeth.
- The presence of any periapical pathosis or bone lesion.
Conditions and Areas for Evaluation on Periodic Visits:
All previously mentioned areas and conditions are and should be part of a periodic dental radiography examination. In addition, the following should be evaluated:
- Ectopic eruption.
- The presence of residual primary roots.
- The possibility of removal of a primary tooth because of interference with the eruption of the permanent tooth
- Proper sequence of eruption
- Evaluation of old restorations and detection of recurrent lesions
- In emergency situations. the degree of pulpal involvement, the amount of alveolar bone loss or the presence of periapical pathosis is detected
- Finally, in the case of traumatic injury, the possibility of a root fracture, and the type and area of the fracture, are evaluated.
Recommended radiographic examination of children and adolescents
Dental radiography should be taken judiciously and only after thoroughly evaluating the patient clinically. The following guidelines can be employed while advising radiographs for a child patient or an adolescent patient.
1. Child patient (before the eruption of the first permanent tooth)
- New patient: 2 bitewing projections of the posterior region
- Recall patients: Bitewing examination at 6 months interval.
Clinically no caries or no increased susceptibility to caries: Bitewing radiograph at 12 to 24 month intervals.
Deep caries: Selected IOPA dental radiography
2. Child patient after the eruption of the first permanent tooth
- New patient: Selected IOPA radiographs, posterior bitewings, occlusal views, and OPG
- Recall patient: Bitewing radiographs and selected IOPA radiographs, if indicated.
- Clinically no caries: Posterior bitewing dental radiography
- Deep caries: Selected IOPA radiograph
3. Adolescent (permanent dentition and before the eruption of the third molars)
- New patient: Posterior bitewing radiographs and a selected IOPA radiograph.
- Recall patient: Posterior bitewing radiograph at 6 to 12 month intervals.
- Clinically no caries: Posterior bitewing radiographs
- Deep caries: A selected IOPA radiograph and or bitewing dental radiography.