X-ray of the maxillofacial region (x-ray of the teeth)

In dental practice, traditional methods of X-ray examination are still used mainly. The method of choice is radiography. Radiography of the maxillofacial region is rarely performed: in some cases, with trauma, to determine the location of foreign bodies, with angio- and sialography. However, radiography is usually combined with radiography.

Depending on the location of the X-ray film in relation to the teeth, intraoral and extraoral methods of radiography are distinguished. Inside-mouth radiographs of teeth can be performed on any X-ray diagnostic apparatus, but the most suitable for these purposes are special dental devices.

For intraoral radiography use a packaged or specially cut (3x4 cm) film, packed in opaque standard packages. The film is pressed in the area under investigation with a finger (contact pictures), retained with the help of special film holders (interproximal shots, "radiography with parallel rays") or closed teeth (snapshots, occlusal).

When radiographing the teeth, the patient sits, resting the back of the head on the headrest, the middle sagittal plane is vertical and perpendicular to the floor of the cabinet. In the case of radiography of the upper teeth, the head is located so that the conditional line connecting the external auditory aperture with the base of the nose is parallel to the floor of the cabinet. When taking pictures of the teeth of the lower jaw, a conditional line running from the external auditory aperture to the corner of the mouth is parallel to the floor of the cabinet.

Intraoral contact (periapical) radiography

Given the shape of the alveolar processes and the peculiarities of the location of the teeth in them, certain rules must be observed in order to obtain an undistorted image. The rule of isometry, or the rule of a bisector, was proposed by Cieszynski in 1906: the central ray is directed to the tip of the root of the tooth being studied perpendicular to the bisector of the angle formed by the tooth axis and the film. With an increase in the angle of inclination of the tube, the length of the tooth decreases, and when it decreases, the length of the tooth increases. In order to facilitate the execution of pictures on the tube of the tube, a scale is shown.

In order to obtain a separate image of the teeth, the central beam of x-rays must pass perpendicular to the tangent (tangent rule) drawn to the arc at the location of the tooth being examined. The central beam of rays is directed to the tops of the roots of the teeth to be examined: on the upper jaw they are projected onto a conditional line running from the tragus of the ear to the base of the nose, at the bottom - 0.5 cm above the lower edge of the bone.

Intraoral roentgenography

X-rays are performed in vain if an intraoral contact image is to be made (increased gag reflex, trismus in children), if necessary, examination of the alveolar process and hard palate, to assess the condition of the cortical plates of the lower jaw and the bottom of the oral cavity. X-rays are used for examination of all teeth of the upper jaw and anterior lower teeth. When taking pictures, the above isometric and tangential rules must be observed.

Interproximal radiographs

The film is held by the film holder or by a piece of thick paper attached to the wrapper of the film and sandwiched between the closed teeth. The central ray is directed perpendicular to the crowns and the film. On the roentgenogram without distortion, the image of the marginal sections of the alveolar processes (interdental septa), the crowns of the upper and lower teeth, is obtained, which is essential in assessing the effectiveness of treatment of periodontal diseases. The technique makes it possible to produce identical pictures in dynamics. At a radiography of all departments carry out 3 - 4 pictures.

Shooting with "parallel rays" ("long-focus radiography") is carried out using a powerful X-ray tube with a localizer tube of 35-40 cm in length. In the mouth, the film is held by a film holder or special rolls of porous materials parallel to the long axis of the tooth. Due to the large focal length, image distortion of the margins and teeth in the image does not occur. The technique provides the possibility of obtaining identical images that are used in periodontology.

Extraoral (x-ray) radiographs

Extraoral radiographs make it possible to assess the state of the divisions of the upper and lower jaws, temporomandibular joints, facial bones not receiving a display or visible only partially on intraoral photographs. In view of the fact that the image of the teeth and the surrounding formations is less structured, extraoral images are used to evaluate them only in cases when it is impossible to perform intraoral x-rays (increased gag reflex, trismus, etc.).

Yu I Vorobyov and M.V. Kotelnikov in 1966-1969 years. A technique for obtaining extraoral x-rays in oblique contact and tangential projections on the dental apparatus was developed. When radiographing the frontal sections of the jaws, the first oblique contact projection is used. A cassette with a film and reinforcing screens is pressed against the superciliary arc on the investigated side, flattening the tip of the nose and displacing it. The head is turned toward the study by approximately 60 °. The central beam of X-rays is directed perpendicularly to the film through the nerve muscle at the level of the angle of the lower jaw.

When radiographing the area of molars and premolars (second oblique contact projection), the cassette is pressed against the malar bone on the investigated side. The central bundle is directed perpendicularly to the film below the lower edge of the lower jaw to the region of the second premolar.

When examining the angle and branch of the lower jaw (third oblique contact projection), the mid-sagittal plane is parallel to the plane of the cassette, pressed to the malar bone on the investigated side. The central beam is directed perpendicularly to the film on the upper part of the branch.

Extraoral contact radiography makes it possible to assess the condition of teeth, marginal parts of alveolar processes, periapical areas, the ratio of the roots of premolars and molars with the maxillary sinus and the mandibular canal.

By informativeness, the technique is not inferior to intraoral contact radiographs.

Radiography in oblique tangential projections is used to assess the state of the vestibular divisions, primarily the upper jaw.

The patient sits in the dental chair, the head rests on the headrest. The central beam of rays is directed along the tangent to the investigated region perpendicular to the cassette with the film and the amplifying screens. Depending on which area is displayed on the contour (central, lateral incisor, canine, premolars, molars), distinguish 5 tangential projections.

The chin-nasal projection is used for examination of the maxilla, maxillary sinuses, nasal cavity, frontal bone of the orbit, zygomatic bones and zygomatic arches.

On the radiographs of the facial skull in the fronto-nasal projection, the upper and lower jaws are visible, the skull base and cervical vertebrae are projected onto them.

Radiography of the body and the branches of the lower jaw in the lateral projection is carried out on the dental X-ray diagnostic apparatus.

An X-ray of the skull in the anterior axial projection is performed to evaluate the walls of the maxillary sinus, including the posterior, nasal cavity, zygomatic bones and arches; It shows the lower jaw in the axial projection.

With the most common method of radiographing the temporomandibular joint on the dental unit, the central beam of X-rays is sent through a half-lunar clipping of the opposite side (according to Parma). The tube is brought as close to the half-lunar tenderloin of the healthy side as possible, thereby providing an increase and clarity of the image, which facilitates the analysis of the radiographic picture of the joint of the investigated side. X-rays of each joint are performed with a closed and open mouth.

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