EMU Evolution of Dental Panoramic Radiography Research Paper
Research Paper
Topic: Talk about the history of Digital panoramic ( x-ray machine that takes digital panoramic images of teeth). Start with the history of film panoramic, then follow with digital. Start with who was the inventor, what year etc.3
Joen Iannucci Laura Jansen Howerton – Dental Radiography_ Principles and Techniques 2016
Saunders – libgenli.pdf
5th edition
Chapter 1
Pg. 20-24
1
Radiation His tory
LE A R N IN G O B J E C T IV E S
After completion of this chapter, the student will be able to do
the following:
1. De ne the key terms associated with dental radiation.
2. Summarize the importance of dental images.
3. List the uses of dental images.
4. Summarize the discovery of x-radiation.
5. Recognize the pioneers in dental x-radiation and their
contributions and discoveries.
6. List the highlights in the history of x-ray equipment and
lm.
7. List the highlights in the history of dental radiographic
techniques.
8. List the highlights in the history of digital imaging.
The dental radiographer cannot appreciate current x-ray technology without looking back to the discovery and history of
x-radiation. A thorough knowledge of x-radiation begins with
a study of its discovery, the pioneers in dental x-radiation, and
the history of dental x-ray equipment, lm, and radiographic
techniques. In addition, before the dental radiographer can
begin to understand x-radiation and its role in dentistry, an
introduction to basic dental imaging terms and a discussion of
the importance of dental images are necessary. The purpose of
this chapter is to introduce basic dental imaging terms, to detail
the importance of dental images, and to review the history of
x-radiation.
Radiography: The art and science of making radiographs by
the exposure of lm to x-rays
Dental radiography: The production of radiographs of the
teeth and adjacent structures by the exposure of an image
receptor to x-rays
Dental radiographer: Any person who positions, exposes, and
processes dental x-ray image receptors
Image: A picture or likeness of an object
Image receptor: A recording medium; examples include x-ray
lm, phosphor plate, or digital sensor
Imaging, dental: The creation of digital, print, or lm
representations of anatomic structures for the purpose of
diagnosis
DENTISTRY AND X-RADIATION
Basic Terminology
Before studying the importance of dental images and the
discovery and history of x-rays, the student must understand the following basic terms pertaining to dentistry and
x-radiation:
Radiation: A form of energy carried by waves or a stream of
particles
X-radiation: A 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 receptors (photographic lm or digital sensors)
Radiology: The science or study of radiation as used in medicine; a branch of medical science that deals with the therapeutic use of x-rays, radioactive substances, and other forms
of radiant energy
Radiograph: An image or picture produced on a receptor
(radiation-sensitive lm, phosphor plate, or digital sensor)
by exposure to ionizing radiation; a two-dimensional representation of a three-dimensional object
Dental radiograph: A photographic image produced on lm by
the passage of x-rays through teeth and related structures
2
Importance of Dental Images
The dental radiographer must have a working knowledge of the
value and uses of dental images. Dental images are a necessary
component of comprehensive patient care. Dental images
enable the dental professional to identify many conditions that
may otherwise go undetected and to see conditions that cannot
be identi ed clinically. An oral examination without dental
images limits the dental practitioner to what is seen clinically—
the teeth and soft tissue. With the use of dental images, the
dental radiographer can obtain a wealth of information about
the teeth and supporting bone.
Detection is one of the most important uses of dental images
(Box 1-1). Through the use of dental images, the dental radiographer can detect disease. Many dental diseases and conditions
produce no clinical signs or symptoms and are typically discovered only through the use of dental imaging.
DISCOVERY OF X-RADIATION
Roentgen and the Discovery of X-rays
The history of dental radiography begins with the discovery of
the x-ray. Wilhelm Conrad Roentgen (pronounced “ren-ken”),
a Bavarian physicist, discovered the x-ray on November 8, 1895
CHAPTER 1
Ra d ia tio n His to ry
3
FIG 1-1 Roe ntge n, the athe r o x-rays , dis cove re d the e arly
pote ntial o an x-ray be am in 1895. (Courte s y Care s tre am He alth
Inc., Roche s te r, NY.)
BO X 1 -1
Us e s o f De ntal Im ag e s
• To de te ct le s ions , dis e as e s , and conditions o the te e th and s urrounding s tructure s that cannot be ide ntif e d clinically
• To conf rm or clas s i y s us pe cte d dis e as e
• To localize le s ions or ore ign obje cts
• To provide in orm ation during de ntal proce dure s (e .g., root canal
the rapy, place m e nt o de ntal im plants )
• To e valuate grow th and de ve lopm e nt
• To illus trate change s s e condary to carie s , pe riodontal dis e as e , and
traum a
• To docum e nt the condition o a patie nt at a s pe cif c point in tim e
• To aid in de ve lopm e nt o a clinical tre atm e nt plan
(Figure 1-1). This monumental discovery revolutionized the
diagnostic capabilities of the medical and dental professions
and, as a result, forever changed the practice of medicine and
dentistry.
Before the discovery of the x-ray, Roentgen had experimented with the production of cathode rays (streams of electrons). He used a vacuum tube, an electrical current, and special
screens covered with a material that glowed ( uoresced) when
exposed to radiation. He made the following observations
about cathode rays:
• The rays appeared as streams of colored light passing
from one end of the tube to the other.
• The rays did not travel far outside the tube.
• The rays caused uorescent screens to glow.
While experimenting in a darkened laboratory with a
vacuum tube, Roentgen noticed a faint green glow coming
from a nearby table. He discovered that the mysterious glow, or
FIG 1-2 Hand m it Ringe n (Hand w ith Rings ): print o Wilhe lm
Roe ntge n’s f rs t “ m e dical” x-ray, o his w i e ’s hand, take n on
22 De ce m be r 1895 and pre s e nte d to Ludw ig Ze hnde r o the
Phys ik Ins titut, Unive rs ity o Fre iburg, on 1 J anuary 1896.
“ uorescence,” was coming from screens located several feet
away from the tube. Roentgen observed that the distance
between the tube and the screens was much greater than the
distance cathode rays could travel. He realized that something
from the tube was striking the screens and causing the glow.
Roentgen concluded that the uorescence must be the result of
some powerful “unknown” ray.
In the following weeks, Roentgen continued experimenting
with these unknown rays. He replaced the uorescent screens
with a photographic plate. He demonstrated that shadowed
images could be permanently recorded on the photographic
plates by placing objects between the tube and the plate. Roentgen proceeded to make the rst radiograph of the human body;
he placed his wife’s hand on a photographic plate and exposed
it to the unknown rays for 15 minutes. When Roentgen developed the photographic plate, the outline of the bones in her
hand could be seen (Figure 1-2).
Roentgen named his discovery x-rays, the “x” referring to the
unknown nature and properties of such rays. (The symbol x is
used in mathematics to represent the unknown.) He published
a total of three scienti c papers detailing the discovery, properties, and characteristics of x-rays. During his lifetime, Roentgen
was awarded many honors and distinctions, including the rst
Nobel Prize ever awarded in physics.
4
PART I Ra d ia tio n Ba s ics
been postulated that Lenard might have discovered the x-ray if
he had used more sensitive uorescent screens.
PIONEERS IN DENTAL X-RADIATION
FIG 1-3 Early Crooke s x-ray tube rom the Mus e um o Wilhe lm
Conrad Roe ntge n in Würzburg, Ge rm any. The s e f rs t-ge ne ration
“ cold cathode ” x-ray tube s w e re us e d rom the 1890s until
about 1920. Copyright Us e r:Aida / Wikim e dia Com m ons /
CC-BY-SA-3.0 [http://cre ative com m ons .org/lice ns e s /by-s a/3.0)]
/ GFDL [https ://e n.w ikipe dia.org/w iki/Wikipe dia:Te xt_o _the
_GNU_Fre e _Docum e ntation_Lice ns e ]
/
https ://com m ons
.w ikim e dia.org/w iki/File :X-ray_tube _2.jpg
Following the publication of Roentgen’s papers, scientists
throughout the world duplicated his discovery and produced
additional information on x-rays. For many years after his discovery, x-rays were referred to as “roentgen rays,” radiology was
referred to as “roentgenology,” and radiographs were known as
“roentgenographs.”
Earlier Experimentation
The primitive vacuum tube used by Roentgen in the discovery
of x-rays represented the collective ndings of many investigators. Before the discovery of x-rays in 1895, a number of European scientists had experimented with uorescence in sealed
glass tubes.
In 1838, a German glassblower named Heinrich Geissler
built the rst vacuum tube, a sealed glass tube from which most
of the air had been evacuated. This original vacuum tube,
known as the Geissler tube, was modi ed by a number of investigators and became known by their respective names (e.g., the
Hittorf-Crookes tube, the Lenard tube).
Johann Wilhelm Hittorf, a German physicist, used the
vacuum tube to study uorescence (a glow that results when a
uorescent substance is struck by light, cathode rays, or x-rays).
In 1870, he observed that the discharges emitted from the negative electrode of the tube traveled in straight lines, produced
heat, and resulted in a greenish uorescence. He called these
discharges cathode rays. In the late 1870s, William Crookes, an
English chemist, redesigned the vacuum tube and discovered
that cathode rays were streams of charged particles. The tube
used in Roentgen’s experiments incorporated the best features
of the Hittorf and Crookes designs and was known as the
Hittorf-Crookes tube (Figure 1-3).
In 1894, Philip Lenard discovered that cathode rays could
penetrate a thin window of aluminum foil built into the walls
of the glass tubes and cause uorescent screens to glow. He
noticed that when the tube and screens were separated by at
least 3.2 inches (8 cm), the screens would not uoresce. It has
After the discovery of x-rays in 1895, a number of pioneers
helped shape the history of dental radiography. The development of dental radiography can be attributed to the research of
hundreds of investigators and practitioners. Many of the early
pioneers in dental radiography died from overexposure to radiation. At the time x-rays were discovered, nothing was known
about the hidden dangers that resulted from using these penetrating rays.
Shortly after the announcement of the discovery of x-rays in
1895, a German dentist, Otto Walkhoff, made the rst dental
radiograph. He placed a glass photographic plate wrapped in
black paper and rubber in his mouth and submitted himself to
25 minutes of x-ray exposure. In that same year, W. J. Morton,
a New York physician, made the rst dental radiograph in the
United States using a skull. He also lectured on the usefulness
of x-rays in dental practice and made the rst whole-body
radiograph using a 3 × 6 ft sheet of lm.
C. Edmund Kells, a New Orleans dentist, is credited with the
rst practical use of radiographs in dentistry in 1896. Kells
exposed the rst dental radiograph in the United States using a
living person. During his many experiments, Kells exposed his
hands to numerous x-rays every day for years. This overexposure to x-radiation caused the development of numerous
cancers in his hands. Kells’ dedication to the development of
x-rays in dentistry ultimately cost him his ngers, later his
hands, and then his arms.
Other pioneers in dental radiography include William H.
Rollins, a Boston dentist who developed the rst dental x-ray
unit. While experimenting with radiation, Rollins suffered a
burn to his hand. This initiated an interest in radiation protection and later the publication of the rst paper on the dangers
associated with radiation. Frank Van Woert, a dentist from
New York City, was the rst to use lm in intraoral radiography. Howard Riley Raper, an Indiana University professor,
established the rst college course in radiography for dental
students.
Table 1-1 lists highlights in the history of dental radiography.
The development of dental radiography has moved forward
from these early discoveries and continues to improve even
today as new technologies become available.
HISTORY OF DENTAL X-RAY EQUIPMENT
In 1913, William D. Coolidge, an electrical engineer, developed
the rst hot-cathode x-ray tube, a high-vacuum tube that contained a tungsten lament. Coolidge’s x-ray tube became the
prototype for all modern x-ray tubes and revolutionized the
generation of x-rays.
In 1923, a miniature version of the x-ray tube was placed
inside the head of an x-ray machine and immersed in oil. This
served as the precursor for all modern dental x-ray machines
and was manufactured by the Victor X-Ray Corporation of
Chicago (Figure 1-4). Later, in 1933, a new machine with
improved features was introduced by General Electric. From
that time on, the dental x-ray machine changed very little until
a variable kilovoltage machine was introduced in 1957. Later, in
1966, a recessed long-beam tubehead was introduced.
CHAPTER 1
T A B LE 1 – 1
Ra d ia tio n His to ry
Hig hlig hts in the His to ry o f De ntal Im ag ing
Ye ar
Eve nt
Pio ne e r/ Manufacture r
Ye ar
Eve nt
1895
1896
1896
Dis cove ry o x-rays
Firs t de ntal radiograph
Firs t de ntal radiograph in Unite d
State s (s kull)
Firs t de ntal radiograph in Unite d
State s (living patie nt)
Firs t pape r on dange rs o
x-radiation
Introduction o bis e cting
te chnique
Firs t de ntal te xt
Firs t pre w rappe d de ntal f lm s
Firs t x-ray tube
Firs t m achine -m ade f lm packe ts
Firs t de ntal x-ray m achine
Introduction o bite -w ing
te chnique
Conce pt o rotational panoram ics
propos e d
Introduction o long-cone
paralle ling te chnique
Introduction o panoram ic
radiography
Introduction o D-s pe e d f lm
(Kodak Ultra-s pe e d)
Firs t variable -kilovoltage de ntal
x-ray m achine
W. C. Roe ntge n
O. Walkho
W. J . Morton
1978
C. E. Ke lls
1987
W. H. Rollins
1989
W. A. Price
1994
H. R. Rape r
Eas tm an Kodak Com pany
W. D. Coolidge
Eas tm an Kodak Com pany
Victor X-Ray Corp, Chicago
H. R. Rape r
1995
Introduction o de ntal
xe roradiography
Introduction o E-s pe e d f lm
(Kodak Ektas pe e d)
Introduction o intraoral digital
im aging in France
De ntal tom ography s canne rs
be com e available
Introduction o Kodak Ektas pe e d
Plus f lm
Introduction o digital s e ns or or
panoram ic unit
Introduction o cone -be am
com pute d tom ography (CBCT)
or de ntal us e
Cone -be am CT s canne rs available
in Europe
Oral and m axillo acial radiology
be com e s a s pe cialty in de ntis try
Introduction o F-s pe e d f lm
(Kodak/Care s tre am De ntal
INSIGHT)
Cone -be am CT s canne rs available
in the Unite d State s
1896
1901
1904
1913
1913
1913
1920
1923
1925
1933
1947
1948
1955
1957
5
1981
1998
1999
1999
F. G. Fitzge rald
2000
2001
Pio ne e r/ Manufacture r
Ge ne ral Ele ctric
prewrapped intraoral lms and consequently increased the
acceptance and use of x-rays in dentistry. The rst machinemade periapical lm packets became available in 1920.
The lms currently used in dental radiography are greatly
improved compared with the lms of the past. At present, fast
lm requires a very short exposure time, less than 2% of the
initial exposure times used in 1920, which, in turn, reduces the
patient’s exposure to radiation.
HISTORY OF DENTAL RADIOGRAPHIC TECHNIQUES
FIG 1-4 Victor CDX s hockproo tube hous ing (1923). (From
Goaz PW, White SC: Oral radiology and principle s of inte rpre tation, e d 2, St Louis , 1987, Mos by.)
HISTORY OF DENTAL X-RAY FILM
From 1896 to 1913, dental x-ray packets consisted of glass
photographic plates or lm cut into small pieces and handwrapped in black paper and rubber. The hand wrapping of
intraoral dental x-ray packets was a time-consuming procedure.
In 1913, the Eastman Kodak Company manufactured the rst
The intraoral techniques used in dentistry include the bisecting technique, the paralleling technique, and the bite-wing
technique. The dental practitioners who developed these
radiographic techniques include Weston Price, a Cleveland
dentist, who introduced the bisecting technique in 1904,
and Howard Riley Raper, who rede ned the original bisecting
technique and introduced the bite-wing technique in 1925.
Raper also wrote one of the rst dental radiography textbooks
in 1913.
The paralleling technique was rst introduced by C. Edmund
Kells in 1896. Later, in 1920, Franklin W. McCormack used the
technique in practical dental radiography. F. Gordon Fitzgerald,
the “father of modern dental radiography,” revived interest in
the paralleling technique with the introduction of the longcone paralleling technique in 1947.
The extraoral technique used most often in dentistry is panoramic radiography. In 1933, Hisatugu Numata of Japan was
the rst to expose a panoramic radiograph; however, the lm
was placed lingually to the teeth. Yrjo Paatero of Finland is
considered to be the “father of panoramic radiography.” He
6
PART I Ra d ia tio n Ba s ics
experimented with a slit beam of radiography, intensifying
screens, and rotational techniques.
HISTORY OF DENTAL DIGITAL IMAGING
Radiographs have been produced using radiographic lm for
well over a century. Traditional radiography is being replaced
by digital imaging in the dental of ce, and is one of the most
signi cant advances that has occurred in dentistry.
Digital imaging allows for instant and easy transmission of
images and electronic storage. The capability to reduce patient
exposure to radiation while increasing diagnostic potential has
profound implications. In addition, chemical waste associated
with traditional radiography is reduced, which bene ts the
environment.
In 1987, the technology that is used to support dental digital
imaging was introduced in France when the rst intraoral
imaging sensor was introduced. In 1989, an article describing
direct digital imaging technology was rst published in U.S.
dental literature. Since then, digital imaging technology has
become widely accepted and has evolved with improvements in
sensor design and supporting technology.
S U M M A RY
• An x-ray is a beam of energy that has the power to penetrate
substances and record image shadows on photographic lm.
• A radiograph is a two-dimensional representation of a threedimensional object.
• An image receptor is a recording medium; examples include
x-ray lm, phosphor plate, or digital sensor.
• Dental imaging is the creation of digital, print, or lm representations of anatomic structures for the purpose of
diagnosis.
• Disease detection is one of the most important uses for
dental images.
• Wilhelm Conrad Roentgen discovered the x-ray in 1895.
• Following the discovery of the x-ray, numerous investigators
contributed to advancements in dental radiography.
• Digital imaging, one of the most signi cant advances in
dentistry, allows for instant review and transmission of
images, reduces patient exposure, and improves the diagnostic potential.
BIBLIOGRAPHY
Frommer HH, Stabulas-Savage JJ: Ionizing radiation and basic principles of
x-ray generation. In Radiology for the dental professional, ed 9, St Louis,
2011, Mosby.
Haring JI, Lind LJ: The importance of dental radiographs and interpretation.
In Radiographic interpretation for the dental hygienist, Philadelphia, 1993,
Saunders.
Johnson ON: History of dental radiography. In Essentials of dental
radiography for dental assistants and hygienists, ed 9, Upper Saddle River,
NJ, 2011, Prentice Hall.
Langlais RP: Exercises in oral radiology and interpretation, ed 4, St Louis, 2004,
Saunders.
Langland OE, Langlais RP: Early pioneers of oral and maxillofacial radiology,
Oral Surg Oral Med Oral Pathol 80(5):496, 1995.
Langland OE, Langlais RP, Preece JW: Production of x-rays. In Principles of
dental imaging, ed 2, Baltimore, MD, 2002, Lippincott Williams and
Wilkins.
Miles DA, Van Dis ML, Williamson GF, et al: X-ray properties and the
generation of x-rays. In Radiographic imaging for the dental team, ed 4,
St Louis, 2009, Saunders.
Mosby’s dental dictionary, ed 2, St Louis, 2008, Mosby.
White SC, Pharoah MJ: Radiation physics. In Oral radiology: principles and
interpretation, ed 7, St Louis, 2014, Mosby.
White SC, Pharoah MJ: Radiation safety and protection. In Oral radiology:
principles and interpretation, ed 7, St Louis, 2014, Mosby.
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