DEN 130 1 H - Dental Radiology= 20

Focus on bisecting technique in dental imaging, covering principles, procedures, equipment, and applications.

Define key terms associated with the bisecting technique.
State the rule of isometry.
Illustrate location of receptor, tooth, imaginary bisector, central ray, and position-indicating device (PID).
List beam alignment devices and receptor holders for the bisecting technique.
Describe receptor size used with bisecting technique.
Explain correct and incorrect horizontal angulation.
Explain correct and incorrect vertical angulation.
State vertical angulation ranges recommended for periapical exposures in the bisecting technique.
State basic rules of bisecting technique.
Detail patient and equipment preparations necessary before using the bisecting technique.
Discuss exposure sequence for 14 periapical receptor placements.
Describe each of the 14 periapical receptor placements recommended for use in the bisecting technique.
List advantages and disadvantages of the bisecting technique.

Purpose: Present key concepts, procedures for patient preparation, equipment preparation, and receptor placements in bisecting technique.
Discuss advantages and disadvantages of the technique with helpful tips.

Key Terms:
- Angle: The figure formed by two rays diverging from a common point.
- Bisect: To divide something into two equal parts.
- Triangle: A polygon with three edges and vertices.
- Equilateral Triangle: A triangle where all three sides are equal in length.
- Right Triangle: A triangle with one angle measuring 90 degrees.
- Congruent Triangles: Triangles that are identical in shape and size.
- Hypotenuse: The longest side of a right triangle, opposite the right angle.
- Isometry: A transformation that preserves lengths, angles, and areas.
- Long axis of the tooth: An imaginary line that runs through the center of the tooth.
- Central ray: The primary axis of the x-ray beam.

Rule of Isometry: States that two triangles are equal if they have two equal angles and share a common side.
In dental imaging, this principle leads to the formation of two imaginary equal triangles.

Receptor Placement: The receptor should be placed along the tooth's lingual surface.
Imaginary Bisector: The angle formed by the receptor and the long axis of the tooth is bisected, creating two imaginary triangles that are right and congruent.
Central ray is directed perpendicular to the imaginary bisector.

Beam Alignment Devices: Tools to position the intraoral receptor.
- Aiming Rings: Facilitate easy alignment of PID and eliminate patient stabilization needs.
- Recommended Devices:
- Rinn BAI System
- Stabe Bite-block
- Rinn Snap-A-Ray Holder
- Ezee Grip digital sensor holder.

Size 2 receptor traditionally used with specific placement orientations:
- Anterior: Long portion in a vertical direction.
- Posterior: Long portion in a horizontal direction.

Angulation: The alignment of the central ray in horizontal and vertical planes.

Definition: The positioning of the tubehead and central ray direction in a side-to-side plane.
Correct Horizontal Angulation: Central ray directed perpendicular to the arch curvature and through contact areas.
Incorrect Horizontal Angulation: Leads to overlapped contact areas.

Definition: Positioning of PID in an up-and-down plane.
Correct Vertical Angulation: Radiographic image is the same length as the tooth.
Incorrect Vertical Angulation: Results in images that do not correspond with the tooth length.
Results of Angulation Errors:
- Foreshortened Images: Caused by excessive vertical angulation.
- Elongated Images: Resulting from insufficient vertical angulation.

Maxillary Teeth:
- Canines: +45 to +55 degrees
- Incisors: +40 to +50 degrees
- Premolars: +30 to +40 degrees
- Molars: +20 to +30 degrees
Mandibular Teeth:
- Canines: -20 to -30 degrees
- Incisors: -15 to -25 degrees
- Premolars: -10 to -15 degrees
- Molars: -5 to 0 degrees

Key Parameters:
- Receptor placement
- Receptor position
- Vertical angulation
- Horizontal angulation
- Receptor exposure

Follow infection control measures and prepare treatment area/supplies.
Seating: Ensure the patient is correctly seated, with adjustments made to their chair and headrest.
Lead Apron: Must be secured, including a thyroid collar.
Remove Objects: Patient should remove eyeglasses and any intraoral objects.

Set appropriate exposure factors before opening sterilized beam alignment device package.

Anterior Positioning:
- Start with maxillary right canine.
- Continue through all maxillary anterior teeth, ending with maxillary left canine.
- Move to mandibular arch, beginning with mandibular left canine and exposing all mandibular anterior teeth, finishing with mandibular right canine.
Posterior Positioning:
- Begin in maxillary right quadrant, transitioning to mandibular right quadrant, then to maxillary left quadrant, finishing in mandibular left quadrant.
- Within each quadrant, expose the premolar receptor first, followed by the molar receptor.

Defined as the specific area for receptor positioning pre-exposure, influenced by the teeth and surrounding structures for radiograph efficacy.

Maxillary Canine: Image must include the entire crown and root, the apex, surrounding structures, and interproximal alveolar bone.
Maxillary Incisor: All four incisors, crowns and roots, including apices and surrounding structures should be visible.
Mandibular Canine: Entire crown and root, apex, and interproximal areas must appear.
Mandibular Incisor: Visibility of the entire crowns and roots of four incisors required, as well as interproximal contacts.

Maxillary Premolar: Should capture all crowns/roots of the first and second premolars and first molar.
Maxillary Molar: Must include crowns/roots of the first, second, and third molars, plus relevant surrounding details.
Mandibular Premolar & Molar: Capture all crowns/roots and adjoining structures necessary.

Open floor for clarifications or further inquiries regarding the bisecting technique in dental imaging.