Dental Radiography and Physics Quiz

History of Dental Radiography

• Wilhelm Conrad Roentgen discovered X-rays in 1895.
• C. Edmund Kells took the first dental radiograph in the U.S.
• The first intraoral sensor was used in 1987.

Radiation Physics

• Atoms contain electrons (-) and protons (+).
• Ionization occurs when an electron is removed from an atom, producing an ion pair.
• Ionizing radiation is radiation that can remove or add electrons to atoms, producing ions.

Uses of Dental Images

• Dental images detect lesions.
• They confirm or classify suspected diseases.
• Dental images localize lesions or foreign objects.
• They provide information during dental procedures.
• Evaluating growth and development is another use.
• Changes secondary to caries, periodontal disease, and trauma can be illustrated.
• The condition of the patient can be documented.
• Clinical treatment plans can be aided.

Parts of the X-Ray Machine

• The control panel controls KVP, mA, and time.
• The extension arm suspends the X-ray tubehead.
• Electrical wires connect the control panel to the tubehead via the extension arm.
• The tubehead houses the X-ray tube, transformers, aluminum disks, and a lead collimator. It also has metal housing, insulating oil, and a tubehead seal. The PID is also part of the tube head apparatus.

Electricity and Electrical Currents

• Amperage (mA) refers to the number of electrons passing through the cathode. Increased mA increases the number of electrons traversing, thereby improving the quantity (or density) of the generated X-rays.
• Voltage (kVp) refers to the speed/power from cathode to anode. Increased kVp increases the quality (or penetrating power) of the X-rays.

Types of Radiation Produced

• General radiation is a type of X-ray.
• Characteristic radiation only occurs at 70 kVp+.
• Primary, secondary, and scatter radiation are produced in an X-ray procedure.

Sequence of Radiation Injury

• The timeframe between exposure and injury indication is the latent period.
• Biological damage is largely caused by free radicals formed in body tissues after exposure to X-rays.
• Repair mechanisms kick in and may fully correct cellular damage; however, long-term damage can accumulate due to prolonged X-ray exposure.
• Injury leads to cell death.
• Recovery is the phase after cell death.
• Cumulative effects occur as a result of repeated exposure to X-rays.

Determining Factors for Radiation Injury

• Total dose, dose rate, tissue quantity, and cell sensitivity influence radiation injury.
• Age also plays a role.

Somatic and Genetic Effects

• Somatic effects impact the patient who is exposed.
• Genetic effects occur in offspring of the exposed individual.

How are we protecting our patients?

• ALARA (As Low As Reasonably Achievable) is the principle of minimizing radiation exposure that is compatible with good clinical practice.
• Proper techniques, including using lead aprons and properly functioning equipment reduce patient exposure.

Operator Protection

• Maintaining distance reduces exposure; it is the most effective form of protection and is easily practiced.
• Avoiding the primary beam via positioning, the use of lead shields, and the utilization of dosimeters (radiosensitive badges) reduce operator radiation exposure.

ALARA Concept

• ALARA stands for As Low As Reasonably Achievable.
• This principle aims to minimize radiation exposure to patients and personnel.

KVP and Time Characteristics

• KVP (kilovoltage peak) alters the energy and therefore the penetration of X-rays (quality).
• Increasing KVP increases the density (amount of black color) in the image.
• mA (milliamperage) and time impact the number of X-rays produced (quantity).
• Increasing mA and/or time increase the density (amount of black color) in the image.

Digital Imaging

• Direct digital imaging systems use CCDs.
• Indirect digital imaging systems use PSPs.
• Exposure times in digital imaging are less than conventional film radiography.

Advantages of Digital Imaging

• The advantages are: higher quality grayscale resolution ; reduction in radiation exposure; faster image review; and reduced equipment and film costs.

Disadvantages of Digital Imaging

• The disadvantages of digital imaging are higher initial setup costs, possible image quality issues, and potential infection control concerns.

Intra-Oral Imaging Techniques

• Paralleling technique is a method used in intraoral imaging; the sensor is parallel to the long axis of the tooth.
• Bisecting technique is an alternative. Bitewing radiographs provide interproximal views.

Extra-Oral Projection Techniques

• Lateral jaw projections, skull projections, and other types of extra-oral projections are used depending on the region being evaluated. Different extraoral positions provide images for different parts of the anatomy.

3-D Imaging Uses

• 3D imaging has a variety of uses, including implant placement, evaluation of dental/facial trauma, and other diagnostic procedures.

Test your knowledge on the history, physics, and applications of dental radiography. This quiz covers key developments, the science behind radiation, and uses of dental imaging in clinical practice. Perfect for students and professionals in dentistry and radiology.