Occlusal Radiography: used to examine large areas of maxilla or mandible on film size 4(for adult),while for children size-2 film can be used. The film is named because the patient occlude or bites on the entire film. Uses of Occlusal Radiography: 1-To locate retained roots of extracted teeth. 2- To locate supernumerary, unerupted or impacted teeth. 3-To locate foreign bodies in the maxilla or mandible. 4- To locate salivary stone in duct of submandibular gland. 5-To locate and evaluate the extent of lesion e.g,cyst ,tumors in maxilla or mandible. 6-To evaluate the boundaries of maxillary sinus. 7-To evaluate fracture of maxilla or mandible. 8-To aid in examination of patients who can not open their mouth more than few millimeters. 9- To examine the area of cleft palate. 10.To measure changes in size and shape of maxilla or mandible. .
Principles of the Occlusal Technique : The film is positioned with white side facing the arch that is being exposed. The film is placed in mouth between the occlusal surfaces of maxillary and mandibular teeth. The film is stabilized when the patient gently bites on the surface of the film.
Anterior Maxillary Occlusal Projection
Main clinical indications:• Periapical assessment of the upper anterior teeth, especially in children and adults unable to tolerate periapical films.• Detecting the unerupted canines, supernumerary teeth and odontomes. Determining the bucco/palatal position of unerupted canines when using the parallax method .• Evaluation of the size and extent of lesions such as cysts or tumors in the anterior maxilla.• Assessment of fractures of the anterior teeth and alveolar bone. It is especially useful in children following trauma because film placement is straightforward.Lateral Maxillary Occlusal Projection (Upper oblique occlusal)
Main clinical indications of Lateral Maxillary Occlusal Projection :• Periapical assessment of the upper posterior teeth, especially in adults unable to tolerate periapical films.• Evaluation of the size and extent of lesions such as cysts, tumors affecting the posterior maxilla.• Assessment the condition of the antram floor. • As an aid to determining the position of roots displaced inadvertently into the antrum during attempted extraction of upper posterior teeth.• Assessment of fractures of the posterior teeth and associated alveolar bone including the tuberosity.Anterior Mandibular Occlusal Projection
Centering point : symphysis menti Direction of beam in the midline , 45° to the plane of the film. Main clinical indications:• Periapical assessment of lower incisor teeth, especially useful in adults and children unable to tolerate periapical films.• Evaluation of the size and extent of lesions affecting the anterior part of the mandible.• Assessment of displaced fractures of the anterior mandible in the vertical plane.Cross-Sectional Mandibular Occlusal Projection
Image field.The soft tissue of the floor of the mouth .The lingual and buccal plates of the mandible from second molar to second molar. To examine the floor of the mouth (e.g., for sialoliths), the exposure time should be reduced to one half the time used to create an image of the mandible.Patient’s head tilted back so that the ala-tragus line is almost perpendicular to the floor. Direct the central ray at the midline through the floor of the mouth approximately 3cm below the chin, at right angles to the center of the film.
Main clinical indications:• Detection of radiopaque calculi in the submandibular salivary ducts .• Assessment of the bucco-lingual position of unerupted mandibular teeth.• Evaluation of the bucco-lingual expansion of the body of the mandible by cysts, tumours.• Assessment of displaced fractures of the anterior body of the mandible in the horizontal plane.
Anterior True Lower Occlusal View
Lateral Mandibular Occlusal ProjectionImage field. The soft tissue of half the floor of the mouth, the buccal and lingual cortical plates of half of the mandible, and the teeth from the lateral incisor to the contralateral third molar. When this view is used to provide an image of the floor of the mouth, the exposure time should be reduced to one half that used to provide an image of the mandible. The alatragus line is almost perpendicular to the floor. Direct the central ray perpendicular to the center of the film through a point beneath the chin, approximately 3 cm posterior to the point of the chin and 3 cm lateral to the midline.