Intraoral Imaging Key Terms Flashcards

11/10/26

What are the three primary types of intraoral radiographic exposures?

Periapical, Interproximal (Bitewing), and Occlusal examinations.

What is the purpose of a Periapical examination?

To examine the entire tooth (crown and root) plus 2 mm to 3 mm of surrounding supporting alveolar bone.

What is the purpose of an Interproximal (Bitewing) examination?

To capture the coronal portions, interproximal contact zones, and crestal alveolar bone of both maxillary and mandibular arches on a single receptor.

What is the purpose of an Occlusal examination?

To record broad segments of either the maxillary or mandibular arch on a large single receptor, showing occlusal surfaces and transverse relationships.

What is a Complete Mouth Series (CMS) or Full Mouth Series (FMX)?

An exhaustive survey of periapical and bitewing radiographs designed to examine all dentulous or edentulous tooth-bearing areas across both arches.

How many total receptors are typically in a Complete Mouth Series (CMS/FMX)?

16 to 20 images (and up to 21 images depending on technique, age, and anatomy).

What is the standard breakdown of exposures in a CMS/FMX?

6 to 8 anterior periapicals, 8 posterior periapicals, and 4 to 6 bitewings.

What does the term "periapical" mean etymologically?

Derived from the Greek "peri" (around) and Latin "apical" (root tip), meaning around the root tip.

What clinical conditions are periapical radiographs used to diagnose?

Pulpal status, periapical pathologies (cysts, granulomas, abscesses), root fractures, impactions, and surrounding periodontal health.

How are anterior periapical receptors oriented and why?

Vertically, to accommodate the narrower arch anatomy and longer crowns and roots of incisors and canines.

How are posterior periapical receptors oriented and why?

Horizontally, to fit the broader posterior anatomy and capture multiple premolars or molars along their horizontal span.

What anatomical landmark is intentionally omitted in a standard bitewing radiograph?

The root apices (if root apices are needed, periapicals must be taken).

What are the four primary diagnostic uses of bitewing radiographs?

1) Detecting interproximal caries, 2) Evaluating restorations for overhangs/open margins/recurrent decay, 3) Detecting subgingival calculus, and 4) Assessing alveolar crestal bone levels.

When are horizontal bitewings vs. vertical bitewings indicated?

Horizontal bitewings are standard when crestal bone loss is minimal or absent; vertical bitewings are indicated for moderate to advanced periodontal disease to see deeper crestal bone loss.

How many vertical bitewings are typically used in a vertical bitewing survey?

Up to 6 vertical exposures (covering premolars, molars, and anterior teeth if indicated).

What two criteria are required for a bitewing image to be considered diagnostic?

Visible crestal alveolar bone and open interproximal contacts (no overlapping contact areas).

What is included in a standard four-image bitewing series vs. a two-image (2 BWX) series?

A 4-image series has 2 premolar and 2 molar bitewings (right and left). A 2-image series has 1 bitewing per side and is used for pediatric patients (before permanent second molars erupt) or adults missing several posterior teeth.

What receptor size is used for an occlusal radiograph and how is it placed?

Size 4 receptor, placed flat between the occlusal surfaces of the teeth like a sandwich.

What conditions are occlusal radiographs essential for identifying?

Retained roots, supernumerary or unerupted teeth, foreign objects, salivary duct stones (sialoliths) in the floor of the mouth, jaw fractures, and cleft palate boundaries.

What is the film composition of a 21-film CMS/FMX series?

21 total films: 12 Size 2 receptors (posterior PAs and bitewings) and 9 Size 1 receptors (narrow anterior PAs).

What is the film composition of an 18-film CMS/FMX series?

18 total films, all Size 2 receptors (6 anterior PAs, 8 posterior PAs, and 4 bitewings).

What is the film composition of a 20-film CMS/FMX series with vertical bitewings?

20 total films, all Size 2 receptors, substituting horizontal bitewings with vertical bitewings for periodontal patients.

Who may legally prescribe dental radiographs and on what basis?

Only a licensed dentist, based solely on an individualized clinical examination and medical necessity (never at fixed, arbitrary calendar intervals).

What are the general historical guidelines for average intervals for an FMX vs. periodic bitewings?

FMX: every 5 to 7 years. Periodic bitewings: every 6 to 18 months depending on individual caries risk and periodontal status.

What does ALARA stand for and what does it require?

As Low As Reasonably Achievable; it requires keeping all radiation exposure to patients and operators to the absolute minimum necessary to obtain diagnostic data.

What protective equipment must be placed on every patient before intraoral radiographs?

A lead apron with an integrated or attached thyroid collar to shield the radiosensitive thyroid gland from scatter radiation.

How must lead aprons and thyroid collars be disinfected and stored?

Disinfected with intermediate-level disinfectant wipes after every patient; hung flat or draped smoothly on a hanger/bar (never folded or creased, which cracks the internal lead sheet).

How does the lead apron protocol differ for panoramic radiography?

A double-sided lead apron (front and back) is used WITHOUT a thyroid collar, because a thyroid collar blocks the rotating beam and creates a large radiopaque triangular ghost image across the anterior mandible.

What are the clinical uses for Intraoral Receptor Sizes 0, 1, 2, and 4?

Size 0: pediatric primary dentition. Size 1: adult anterior PAs and small child posterior bitewings. Size 2: standard adult posterior PAs and bitewings. Size 4: occlusal radiographs.

What items make up the standard armamentarium for a CMS/FMX tray setup?

Rinn XCP beam alignment devices, 18–20 films/plates (or wired digital sensor), barrier envelopes/sleeves, film/software mount, labeled disposable cup for exposed films, and lead apron with thyroid collar.

Define Parallel, Perpendicular, Long Axis of the Tooth, and Central Ray (CR).

Parallel: equidistant lines/planes that never intersect. Perpendicular: at a 90° right angle. Long Axis: imaginary line dividing the tooth longitudinally from crown to root apex. Central Ray: central core of the primary x-ray beam.

What are the alternative names for the Paralleling Technique and why is it the ADA standard of care?

Also called Extension Cone Paralleling (XCP), Right-Angle, or Rinn Technique. Endorsed by the ADA because it eliminates angulation guesswork, minimizes dimensional distortion, preserves root lengths, and reduces radiation exposure.

What is Rule 1 (Receptor Placement) of the Paralleling Technique?

The receptor must cover the specific teeth and surrounding structures designated for each exposure (anterior teeth centered vertically; posterior teeth centered horizontally).

What is Rule 2 (Receptor Position) of the Paralleling Technique?

The receptor must be positioned parallel to the long axis of the tooth, placed away from the tooth toward the midline of the oral cavity to accommodate palatal curvature and alveolar slope.

What is Rule 3 (Vertical Angulation) of the Paralleling Technique?

The central ray of the x-ray beam must be directed strictly perpendicular (90°) to both the receptor and the long axis of the tooth.

What is Rule 4 (Horizontal Angulation) of the Paralleling Technique?

The central ray must be directed straight through the interproximal contact areas between adjacent teeth to prevent contact overlapping.

What is Rule 5 (Central Ray Alignment) of the Paralleling Technique and what happens if it fails?

The primary x-ray beam must be completely centered over the receptor and aiming ring; failure to align the beam results in a partial exposure defect called a cone-cut.

What do the Rinn XCP color codes Blue, Yellow, and Red represent?

Blue: Anterior Periapicals (vertical). Yellow: Posterior Periapicals (horizontal). Red: Bitewings (horizontal or vertical).

How should a patient be positioned and prepared prior to intraoral x-ray exposure?

Seated upright with the maxillary occlusal plane parallel to the floor, draped with a lead apron and snug thyroid collar, with eyeglasses, removable dental prostheses (dentures/retainers), and oral/facial piercings removed.

Why do systematic intraoral exposure sequences always begin with the anterior teeth?

Anterior receptors are smaller and more comfortable, are less likely to trigger a gag reflex, and help the patient adjust to the biteblock before moving to sensitive posterior areas.

What is the standard anterior exposure sequence using the Blue Rinn XCP?

Start at maxillary right canine (#6), move across to maxillary left canine (#11), drop down to mandibular left canine (#22), and move across to mandibular right canine (#27).

What is the standard posterior exposure sequence using the Yellow Rinn XCP?

Maxillary right premolars (#4–5) -> maxillary right molars (#1–3) -> mandibular left premolars (#20–21) -> mandibular left molars (#17–19) -> reassemble for maxillary left premolars/molars -> mandibular right premolars/molars.

What is the standard bitewing exposure sequence and what vertical angulation is used if using bite tabs without an aiming ring?

Right premolar BWX -> right molar BWX -> left premolar BWX -> left molar BWX. When using bite tabs without an aiming ring, set vertical angulation to approximately +10°.

What is the "Dot in the Slot" rule and why is it important?

The raised embossed dot on intraoral film must face the incisal/occlusal edge inside the biteblock slot so it does not obscure diagnostic details at the root apex, and so its orientation identifies right vs. left during mounting.

What is the "White in the Ring" rule and what happens if a film is exposed backward?

The plain white exposure side must face the x-ray tube head centered inside the aiming ring. Exposing the colored/labeled lead-foil back side causes a herringbone/tire-track artifact and severe underexposure.

How do you adjust receptor placement for a patient with Torus Palatinus (Maxillary Torus)?

Place the receptor on the far palatal side of the torus (further away from the teeth) into the deepest section of the vault to maintain parallelism rather than resting it on top of the bony growth.

How do you adjust receptor placement for a patient with Mandibular Tori (Torus Mandibularis)?

Place the receptor lingual to the tori, deeper toward the center of the tongue (away from the sensitive lingual mucosa), and gently angle it until the patient bites down.

What do maxillary and mandibular tori look like on a radiograph?

Distinct, dense, well-defined, smooth radiopaque masses superimposed over the coronal and middle thirds of the tooth roots.

What causes Overlapping on a radiograph and how do you fix it?

Caused by a horizontal angulation error where the central ray does not pass straight through the interproximal spaces. Fix by adjusting the tube head horizontally perpendicular to the arch curve and receptor.

What causes Elongation vs. Foreshortening on a radiograph?

Elongation (teeth look abnormally long/stretched) is caused by insufficient/too flat vertical angulation (like a low sun casting a long shadow). Foreshortening (teeth look short/blunted) is caused by excessive/too steep vertical angulation (like a high midday sun).

What is Cone-Cutting, what causes it, and how do you fix it?

A clear, unexposed curved or straight radiopaque border on the film caused by failing to center the PID/cylinder over the aiming ring. Fix by centering the PID completely over the aiming ring before exposing.