Dental Radiography Principles and Techniques: Radiation History

Dental Radiography Principles and Techniques: Radiation History

Introduction

  • The first part of the notes covers the purpose of the material and basic terminology relevant to dental radiography and imaging.

  • Purpose includes:

    • To introduce basic dental imaging terms

    • To detail the importance of dental images

    • To review the history of x-radiation

Key Concepts and Definitions

Radiation Terminology

  • Radiation: Energy carried by waves or streams of particles.

  • X-radiation: High-energy radiation produced by the collision of a beam of electrons with a metal target in an x-ray tube.

  • X-ray: A beam of energy that has the power to penetrate substances and record image shadows on photographic film.

  • Radiology: The science or study of radiation as used in medicine; a branch of medical science that deals with the use of x-rays, radioactive substances, and other forms of radiant energy in the diagnosis and treatment of disease.

  • Radiograph: A picture (visible photographic record) on film produced by the passage of x-rays through an object or body; also referred to as x-ray film. In practice, often simply called an “x-ray,” which is not technically correct since x-ray refers to the energy beam itself.

  • Dental radiograph: A photographic image produced on film by the passage of x-rays through teeth and related structures.

  • Radiography: The art and science of making radiographs by the exposure of film to x-rays.

  • Dental radiography: The production of radiographs of the teeth and adjacent structures by the exposure of film to x-rays.

  • Dental radiographer: Any person who positions, exposes, and processes x-ray film.

  • Image: A picture or likeness of an object.

  • Image receptor: A recording medium (e.g., x-ray film, phosphor plate, digital sensor).

  • Imaging, dental: The creation of digital, print, or film representations of anatomic structures for the purpose of diagnosis.

Importance and Uses of Dental Images

  • Dental images play a critical role by enabling dental professionals to identify conditions that might otherwise go undetected.

  • Functions of dental images include:

    • Detecting lesions

    • Confirming or classifying suspected diseases

    • Localizing lesions or foreign objects

    • Providing information during dental procedures

    • Evaluating growth and development

    • Illustrating changes secondary to caries, periodontal disease, trauma

    • Documenting the condition of a patient

    • Aiding in the development of a clinical treatment plan.

Discovery of X-Radiation and Pioneers in Dental X-Radiation

Discovery of X-Rays (Wilhelm Conrad Roentgen, 1895)

  • Roentgen conducted experiments with vacuum tubes and fluorescent screens, observing that screens glowed even several feet away from the tube. This led to his discovery of x-radiation as a mysterious ray causing the screens to glow.

  • Crookes Tube: A vacuum tube generating cathode rays, which caused a fluorescent plate to glow, leading to early insights into x-rays.

Earlier Experimentations

  • Heinrich Geissler (1838): Built the first vacuum tube.

  • Johann Hittorf (1870): Studied fluorescence using the vacuum tube.

  • William Crookes (Late 1870s): Discovered that cathode rays consisted of streams of charged particles.

  • Philip Lenard (1894): Demonstrated that cathode rays could penetrate thin aluminum foil.

Pioneers in Dental X-Radiation

  • Otto Walkhoff (1895): Made the first dental radiograph with a 25-minute exposure.

  • W.J. Morton (1895): Created the first radiograph using a skull.

  • C. Edmund Kells (1896): Exposed the first dental radiograph in the U.S. using a live person and introduced the paralleling technique.

History of Dental Radiographic Techniques

  • C. Edmund Kells (1896): Introduced the paralleling technique.

  • William H. Rollins: Developed the first dental x-ray unit.

  • Frank VanWoert: First to use film in intraoral radiography.

  • Howard Riley Raper: Established the first college course in radiography for dental students.

  • Subsequent advancements include:

    • William Coolidge (1913): Developed the first hot cathode x-ray tube.

    • Victor X-Ray Corporation (1923): Implemented oil immersion of the tubehead.

    • Innovations in equipment continued through the 1950s and 1960s.

History of Dental Radiographic Techniques (Detailed)

  • Weston Price (1904): Introduced the bisecting technique.

  • Howard Riley Raper (1925): Refined the bisecting technique and introduced the bitewing technique.

  • F. Gordon Fitzgerald (1947): Introduced the long-cone paralleling technique.

  • Hisatugu Numata (1933): First to expose a panoramic radiograph.

  • Yrjo Paatero: Experimented with various imaging techniques like slit beam radiography and rotational techniques.

Digital Imaging in Dentistry

  • Traditional radiography has been in use for over a century. However, digital imaging is replacing traditional methods due to advantages such as instant transmission of images and electronic storage.

  • Key milestones in digital imaging:

    • 1987: Introduction of the first intraoral imaging sensor.

    • 1989: An article discussing direct digital imaging technology was published in the U.S. dental literature.

Three-Dimensional Imaging

  • 1999: Introduction of cone-beam computed tomography to dentistry, allowing for 3D visualization of oral structures for diagnostics and surgical guidance.

Oral and Maxillofacial Radiology Education

  • In 1999, the American Dental Association (ADA) recognized Oral and Maxillofacial Radiology (OMFR) as its ninth specialty program, offering advanced training and requiring a 2-3 year residency after completing dental school, in addition to passing an international board examination.

Conclusion

  • Understanding the historical context and terminology of dental radiography is imperative for dental professionals to effectively utilize imaging in practice.