Intra-oral Radiograph

February 20, 2011 by Lee Chun Hoe

Dental intra-oral radiographs a.k.a X-rays. Dentists use radiographs for multiple reasons: to find hidden dental structures, malignant or benign masses, bone loss, and cavities.

How does x-ray of your teeth formed?

X-ray of your teeth is formed by a controlled burst of X-ray radiation which penetrates oral structures at different levels, depending on varying anatomical densities, before striking the film or sensor.

Teeth appear lighter because less radiation penetrates them to reach the film.
Dental caries, infections and other changes in the bone density, and the periodontal ligament, appear darker because X-rays readily penetrate these less dense structures.
Dental restorations (fillings, crowns) may appear lighter or darker, depending on the density of the material.

Should Patients Have Concerns About Radiation Exposure?

The dosage of X-ray radiation for dental is typically safe, around 0.150 mSv for a full mouth series, according to the American Dental Association website. It is equivalent to a few days’ worth of background environmental radiation exposure, or similar to the dose received during a cross-country airplane flight (concentrated into one short burst aimed at a small area).

Incidental exposure is further reduced by the use of a lead shield, lead apron, sometimes with a lead thyroid collar. Operator exposure is reduced by stepping out of the room, or behind adequate shielding material, when the X-ray source is activated.

Types of intra-oral radiographs

Bitewing
Periapical

Bitewing radiograph

Bitewing radiograph designed the placement of the film packet to reveal the coronal halves of the maxillary and mandibular teeth, inter-proximal contacts and portions of the interdental septa.

It is indicated primarily to detect or monitor interproximal caries if the proximal surfaces of the teeth cannot be visually or tactilely examined.

Occlusal caries, crestal alveolar bone level and secondarily for eruption patterns, caries and restoration proximity to pulp spaces, primary molar furcation pathology and developmental anomalies may also be detected with bitewing radiographs.

Periapical Radiograph

PA radiography describes intra-oral techniques designed to show individual teeth and the tissues around the apices. Each image usually shows two to four teeth and provides detailed information about the teeth and the surrounding alveolar bone.

Indications for PA radiograph are:

Detection of apical infection/inflammation
Assessment of the periodontal status
After trauma to the teeth and associated alveolar bone
Assessment of the presence and position of unerupted teeth
Assessment of root morphology before extractions
During endodontics
Preoperative assessment and postoperative appraisal of apical surgery
Detailed evaluation of apical cysts and other lesions within the alveolar bone
Evaluation of implants postoperatively.