Intra-oral radiographs Part 2 Flashcards
Indications for Bitewing radiographs
Detection of interproximal caries (posterior teeth)
Detecting occlusal caries
Monitoring progression of dental caries
Detection of secondary/residual caries below restorations
Assessment of existing restorations
Assessment of the periodontal status
useful for evaluating alveolar bone crest and changes in bone height can be assessed by comparison with the adjacent teeth.
Height of the pulp chamber (pulp horns)
Interproximal contour/contact of restorations; overhangs
To detect interproximal calculus
for better visualization exposure should be reduced* as calculus has relatively low density
Principles of bitewing
The film is placed in the mouth parallel to the crowns of both the upper and lower teeth.
The film is stabilized when the patient bites on the bitewing tab of bitewing holder.
The central ray of the x-ray beam is directed through the contacts of the teeth, using a +10 degree vertical angulation
Four types of bitewing films are available. (Also available as phosphor plates)
Size 0-used to study posterior teeth of children, always placed horizontally. 22*35
Size 1-used to examine posterior teeth in mixed dentitions or anterior teeth of adults. It is placed horizontally for the former and vertically to the latter.
Size 2-used to examine posterior teeth of adults and is always kept horizontally. 32*41
Size 3- a longer and narrower film used only for posterior bitewing radiographs
spans horizontally from premolar to molar areas (1 film per side L and R)
results in overlapping of the contacts
Advantages of film holder
Film packet can be held firmly and cannot be displaced by the tongue.
Position of the holder relative to the teeth is recordable and reproducible.
Position of the x-ray tube head determined by the holder ensuring that the x-ray beam is always at right angles to the film packet.
Avoids coning off the anterior part of the film (cone cutting)
All parts of the holder are autoclavable
Position indicating device and angulation
If the bitewing holder is used, the aiming ring indicates the proper PID angulations.
If the bitewing tab is used, then both the horizontal and vertical angulations must be precisely determined.
Horizontal angulations – the central ray is perpendicular to the curvature of the arch and through the contact areas of teeth.
Vertical angulations
the central ray is perpendicular to the long axis of tooth,
a +10o vertical angulation is recommended for the bitewing radiograph,
to compensate for the slight bend of the upper portion of the film and the slight tilt of the maxillary teeth
Anatomic structures found in a bitewing
Interproximal areas
Crestal bone
Crowns
Horizontal vs Vertical bitewings
Vertical bite-wing radiographs can be used to examine
reduced alveolar bone level even when bone loss has been considerable and are best used as a post treatment or follow-up film
Horizontal bite-wing radiograph cannot adequately
visualize severe bone loss but they can
best demonstrate proximal and secondary caries
Position indicating device and angulation
If the bitewing holder is used, the aiming ring indicates the proper PID angulations.
If the bitewing tab is used, then both the horizontal and vertical angulations must be precisely determined.
Horizontal angulations – the central ray is perpendicular to the curvature of the arch and through the contact areas of teeth.
Vertical angulations
the central ray is perpendicular to the long axis of tooth,
a +10o vertical angulation is recommended for the bitewing radiograph,
to compensate for the slight bend of the upper portion of the film and the slight tilt of the maxillary teeth.
Occlusal radiographs Indications
To locate retained roots of extracted teeth.
To locate supernumerary, unerupted or impacted (canine/third molar) teeth.
To locate foreign bodies in either jaws.
To locate salivary stones in Wharton’s duct in the floor of mouth.
To locate and evaluate the extent of lesions (e.g.. cyst, tumor, tori, etc.) in the maxilla and mandible.
Sequestra
Edentulous patients
Occlusal size film
Occlusal film Size 4 (3 times larger than Size-2 films) (57x76mm) for adults
However, can be used in children (folded in half)
