Textbook of Oral Medicine Oral Diagnosis and Oral Radiology - Free ebook download as PDF File .pdf), Text File .txt) or read book online for free. fssf. Textbook of Dental. Radiology. 2d ed. Olaf E. Langland,. D.D.S., M.S., Francis. H. Sippy,. B.S., tvnovellas.info, and Robert. P. Langlais,. D.O.S., M.S.. Springfield. As a testament to its widespread use as a textbook in dental student education in the United States, Oral Radi- ology: Principles and Interpretation is now.
|Language:||English, Spanish, Arabic|
|Genre:||Business & Career|
|ePub File Size:||28.72 MB|
|PDF File Size:||17.83 MB|
|Distribution:||Free* [*Sign up for free]|
Evolve ® Student Resources for White/Pharoah: Oral Radiology: Principles and . Each new edition of this textbook provides the opportunity to include. download Textbook of Oral Radiology - 2nd Edition. Print Book & E-Book. ISBN , tvnovellas.info Textbook of Dental Radiology Second Edition. Professor and Head Department of Oral Medicine, Oral Diagnosis and.
No part of this publication should be reproduced, stored in a retrieval system, or transmitted in any form or by any means: electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the author and the publisher. This book has been published in good faith that the material provided by author is original. Every effort is made to ensure accuracy of material, but the publisher, printer and author will not be held responsible for any inadvertent error s. In case of any dispute, all legal matters are to be settled under Delhi jurisdiction only. To My Teachers for Teaching me the values and virtues of life, Opening new vistas of ever-broadening knowledge, Taking me out of my ignorance, Patience in teaching to make me understand, Unselfishness in imparting knowledge, And above all for helping me reach where I am. The time constraint and the cost factor were unfavorable for the average student to buy all these books.
He then entered the University of Utrecht in to study physics. Not having attained the credentials required for a regular student, and hearing that he could enter the Polytechnic History of Radiation 5 at Zurich by passing its examination, he passed this and began studies there as a student of mechanical engineering.
He attended the lectures given by Clausius and also worked in the laboratory of Kundt. Both Kundt and Clausius exerted great influence on his development. In he received PhD from the University of Zurich, was appointed assistant to Kundt and went with him to Wrzburg in the same year, and three years later to Strasbourg.
In , he qualified as Lecturer at Strasbourg University and in , he was appointed Professor in the Academy of Agriculture at Hohenheim in Wurtemberg.
In he returned to Strasbourg as Professor of Physics, but three years later he accepted the invitation to the Chair of Physics in the University of Giessen. After having declined invitations to similar positions in the Universities of Jena and Utrecht , he accepted it from the University of Wrzburg , where he succeeded Kohlrauschund found among his colleagues Helmholtz and Lorenz. In he declined an offer to the Chair of Physics in the University of Leipzig, but in , he accepted it in the University of Munich, by special request of the Bavarian government, as successor of E Lommel.
Here he remained for the rest of his life, although he was offered, but declined, the Presidency of the Physikalisch-Technische Reichsanstalt at Berlin and the Chair of Physics of the Berlin Academy. Roentgens first work was published in , dealing with the specific heats of gases, followed a few years later by a paper on the thermal conductivity of crystals.
Among other problems he studied were the electrical and other characteristics of quartz; the influence of pressure on the refractive indices of various fluids; the modification of the planes of polarized light by electromagnetic influences; the variations in the functions of the temperature and the compressibility of water and other fluids; the phenomena accompanying the spreading of oil drops on water.
Roentgens name, however, is chiefly associated with his discovery of the rays that he called x-rays. In he was 6 Textbook of Dental Radiology studying the phenomena accompanying the passage of an electric current through a gas of extremely low pressure. Previous work in this field had already been carried out by J Plucker , JW Hittorf , CF Varley , E Goldstein , Sir William Crookes , H Hertz and Ph Von Lenard , and by the work of these scientists the properties of cathode rays, the name given by Goldstein to the electric current established in highly rarefied gases by the very high tension electricity generated by Ruhmkorffs induction coil, had become wellknown.
Roentgens work on cathode rays led him, however, to the discovery of a new and different kind of rays. On the evening of November 8, , he found that, if the discharge tube is enclosed in a sealed, thick black carton to exclude all light, and if he worked in a dark room, a paper plate covered on one side with barium platinocyanide placed in the path of the rays became fluorescent even when it was as far as two meters from the discharge tube.
During subsequent experiments he found that objects of different thicknesses interposed in the path of the rays showed variable transparency to them when recorded on a photographic plate. When he immobilized for some moments the hand of his wife in the path of the rays over a photographic plate, he observed after development of the plate an image of his wifes hand which showed the shadows thrown by the bones of her hand and that of a ring she was wearing, surrounded by the penumbra of the flesh, which was more permeable to the rays and therefore threw a fainter shadow.
This was the first roentgenograms ever taken. In further experiments, Roentgen showed that the new rays are produced by the impact of cathode rays on a material object.
Because their nature was then unknown, he gave them the name x-rays. Later, Max von Laue and his pupils showed that they are of the same electromagnetic nature as light, but differ from it only in the higher frequency of their vibration. History of Radiation 7 Numerous honors were showered upon him.
In several cities, streets were named after him, and a complete list of prizes, medals, honorary doctorates, honorary and corresponding memberships of learned societies in Germany as well as abroad, and other honors would fill a whole page of this book. In spite of all this, Roentgen retained the characteristic of a strikingly modest and reticent man. Throughout his life he retained his love of nature and outdoor occupations. Many vacations were spent at his summer home at Weilheim, at the foot of the Bavarian Alps, where he entertained his friends and went on many expeditions into the mountains.
He was a great mountaineer and more than once got into dangerous situations. Amiable and courteous by nature, he always understood the views and difficulties of others. He was always shy of having an assistant, and preferred to work alone. He built much of the apparatus he used with great ingenuity and experimental skill.
Roentgen married Anna Bertha Ludwig of Zurich, whom he had met in the caf run by her father. She was a niece of the poet Otto Ludwig. They got married in in Apeldoorn, The Netherlands. They had no children, but in adopted Josephine Bertha Ludwig, then aged 6, daughter of Mrs. Roentgens only brother. Four years after his wifes death, Roentgen died at Munich on February 10, , due to carcinoma of the intestine. History of Radiography X-rays were discovered in , by Wilhelm Conrad Roentgen , see the biographical sketch who was a Professor at Wurzburg University in Germany.
Like most of the scientific discoveries, even the discovery of x-rays was accidental at a time when Roentgen was experimenting with the production of cathode rays. Cathode rays are nothing but stream of electrons.
For his experiment, he used the following: 8 Textbook of Dental Radiology Vacuum tube An electrical current Special screens covered with a material, which fluoresces when exposed to radiation. While experimenting in his darkened laboratory with a cathode ray tube, Roentgen noticed a faint and fluorescent glow coming from a table kept several feet away on which the fluorescent screens were kept.
It was readily apparent to him that the cathode rays could never travel that far. This curious scientific observation prompted him to conclude that these rays were different and hence he named these rays as x-rays. The tube that Roentgen was working with consisted of a glass envelope bulb with positive and negative electrodes encapsulated in it.
The air in the tube was evacuated, and when a high voltage was applied, the tube produced a fluorescent glow. Roentgen shielded the tube with heavy black paper, and discovered a green-colored fluorescent light generated by a material located a few feet away from the tube. He concluded that a new type of rays was being emitted from the tube.
This ray was capable of passing through the heavy paper covering and exciting the phosphorescent materials in the room. He found that the new ray could pass through most substances casting shadows of solid objects. Roentgen also discovered that the ray could pass through the tissue of humans, but not bones and metal objects.
One of Roentgens first experiments late in was a film of the hand of his wife, Bertha Fig. It is interesting that the first use of x-rays were for an industrial not medical application, as Roentgen produced a radiograph of a set of weights in a box to show his colleagues.
Roentgens discovery was a scientific bombshell, and was received with extraordinary interest by both scientists and laymen.
Scientists everywhere could duplicate his experiment because the cathode tube was very well known during this History of Radiation 9 Fig. Many scientists dropped other lines of research to pursue the mysterious rays. Newspapers and magazines of the day provided the public with numerous stories, some true, others fanciful, about the properties of the newly discovered rays. Public fancy was caught by this invisible ray that had the ability to pass through solid matter, and, in conjunction with a photographic plate, provided a picture of the bones and internal body parts.
Scientific curiosity arose by the demonstration of wavelength of x-rays which is shorter than light.
This generated new possibilities in physics, and for investigating the structure of matter. Much enthusiasm was generated about potential applications of x-rays as an aid in medicine and surgery.
Within a month after the announcement of the discovery, several medical radiographs had been made in Europe and in the United States, which were used by surgeons to guide them in their work.
In June , only 6 months after Roentgen announced his discovery, x-rays were being used by battlefield physicians to locate bullets in wounded soldiers. The reason that x-rays were not used in industrial application before this date was because the x-ray tubes the source of the x-rays broke down under the voltages required to produce rays of satisfactory penetrating power for industrial purposes.
However, that changed in when the high vacuum x-ray tubes designed by Coolidge became available. The high vacuum tubes were an intense and reliable x-ray source, operating at energies up to , volts. In , industrial radiography took another step forward with the advent of the ,volt x-ray tube that allowed radiographs of thick steel parts to be produced in a reasonable amount of time. In , General Electric Company developed 1,, volt x-ray generators, providing an effective tool for industrial radiography.
That same year, the American Society of Mechanical Engineers ASME permitted x-ray approval of fusion welded pressure vessels that further opened the door to industrial acceptance and use Fig. A Second Source of Radiation Shortly after the discovery of x-rays, another form of penetrating rays was discovered.
In , French scientist Henri Becquerel discovered natural radioactivity. Many scientists of History of Radiation 11 that period were working with cathode rays, and other scientists were gathering evidence on the theory that the atom could be subdivided.
Some of the researches showed that certain types of atoms disintegrate by themselves. It was Henri Becquerel who discovered this phenomenon while investigating the properties of fluorescent minerals. Becquerel was researching the principles of fluorescence, wherein certain minerals glow fluoresce when exposed to sunlight. He utilized photographic plates to record this fluorescence.
One of the minerals Becquerel worked with was a uranium compound. On a day when it was too cloudy to expose his samples to direct sunlight, Becquerel stored some of the compound in a drawer with his photographic plates. Later when he developed these plates, he discovered that they were fogged exhibited exposure to light. Becquerel wondered as to what would have caused this fogging.
He knew he had wrapped the plates tightly before using them, so the fogging was not due to stray light. In addition, he noticed that only the plates that were in the drawer with the uranium compound were fogged. Becquerel concluded that the uranium compound gave off a type of radiation that could penetrate heavy paper and expose photographic film.
Becquerel continued to test samples of uranium compounds and determined that the source of radiation was the element uranium. Becquerels discovery was, unlike that of the x-rays, virtually unnoticed by laymen and scientists alike.
Relatively few scientists were interested in Becquerels findings. It was not until the discovery of radium by the Curies two years later that interest in radioactivity became widespread. While working in France at the time of Becquerels discovery, Polish scientist Marie Curie became very interested in his work.
She suspected that a uranium ore known as pitchblende contained other radioactive elements. Marie and her husband, French scientist Pierre Curie, started looking for these other elements. In , the Curies discovered another radioactive element in pitchblende, and named it polonium in honor of Marie Curies native homeland. Later that year, the Curie 12 Textbook of Dental Radiology discovered another radioactive element which they named radium, or shining element".
Both polonium and radium were more radioactive than uranium. Since these discoveries, many other radioactive elements have been discovered or produced. Radium became the initial industrial gamma ray source. The material allowed castings up to 10 to 12 inches thick to be radiographed. During World War II, industrial radiography grew tremendously as part of the Navys shipbuilding program. In , man-made gamma ray sources such as cobalt and iridium became available.
These new sources were far stronger than radium and were much less expensive. The man-made sources rapidly replaced radium, and use of gamma rays grew quickly in industrial radiography. Health Concerns The science of radiation protection, or health physics as it is more properly called, grew out of the parallel discoveries of x-rays and radioactivity in the closing years of the 19th century.
Experimenters, physicians, laymen, and physicists alike setup x-ray generating apparatuses and proceeded about their labors with a lack of concern regarding potential dangers. Such a lack of concern is quite understandable, for there was nothing in previous experience to suggest that x-rays would in any way be hazardous. Indeed, the opposite was the case, for who would suspect that a ray similar to light but unseen, unfelt, or otherwise undetectable by the senses would be damaging to a person?
More likely, or so it seemed to some, x-rays could be beneficial for the body. Inevitably, the widespread and unrestrained use of x-rays led to serious injuries. Often injuries were not attributed to x-ray exposure, in part because of the slow onset of symptoms, and because there was simply no reason to suspect x-rays as the cause. Some early experimenters did tie x-ray exposure and skin burns together.
The first warning of possible adverse effects of x-rays came from Thomas Edison, William J Morton, and Nikola Tesla who each reported eye irritations from experimentation with x-rays and fluorescent substances. History of Radiation 13 Today, it can be said that radiation ranks among the most thoroughly investigated causes of disease. Although much still remains to be learned, more is known about the mechanisms of radiation damage on the molecular, cellular, and organ system than is known for most other health stressing agents.
Indeed, it is precisely this vast accumulation of quantitative dose-response data that enables health physicists to specify radiation levels so that medical, scientific, and industrial uses of radiation may continue at levels of risk no greater than, and frequently less than, the levels of risk associated with any other technology. X-rays and gamma rays are electromagnetic radiation of exactly the same nature as light, but of much shorter wavelength.
Wavelength of visible light is on the order of angstroms while the wavelength of x-rays is in the range of one angstrom and that of gamma rays is 0. This very short wavelength is what gives x-rays and gamma rays their power to penetrate materials that light cannot. These electromagnetic waves are of a high energy level and can break chemical bonds in materials they penetrate.
If the irradiated matter is living tissue, the breaking of chemical bonds may result in altered structure or a change in the function of cells. Early exposures to radiation resulted in the loss of limbs and even lives. Men and women researchers collected and documented information on the interaction of radiation and the human body.
This early information helped science understand how electromagnetic radiation interacts with living tissue. Unfortunately, much of this information was collected at great personal expense. Considerable improvizations of the previously crude equipments have also taken place. The earlier equipments were using a higher exposure time for getting the image. However, 14 Textbook of Dental Radiology the knowledge about the harmful effects of x-radiation has helped in the designing of equipments which required less exposure time.
It must also be emphasized that quite a lot of research activities are going on in the development of newer imaging modalities that could truly revolutionize the science of dental radiology. The chronology of these events in the evolution of dental radiology is summarized and given below. This was then considered to be a fourth state of matter, other than the solid, liquid, and gaseous states.
He also proposed the principle of keeping History of Radiation 15 the film and object at right angles to the source of x-ray. Frank Harrison, an English dentist made dental radiographs with 10 minutes of exposure time. His images could differentiate the tooth structure and pulp chamber. He also reported the harmful effects of radiation. Wilhelm Koenig in Frankfurt made 14 dental radiographs. Dr Otto Walkoff made radiographs of the molars with an exposure time of 25 minutes.
William J Morton used roll film. Roentgen was awarded the Nobel Prize in Physics. Kells described time-temperature method of film processing. Weston A Price, a Cleveland dentist, described paralleling technique and bisecting-angle technique. Franklin W McCormack proposed long distance technique. William D Coolidge, an electrical engineer, developed first hot cathode x-ray tube with tungsten filament. Dental x-ray packets consisted of glass photographic plates or films cut into small pieces and hand-wrapped.
Wrapped and moisture-proof dental film packet containing two films were introduced in the market. Howard Riley Raper introduced angle meter. Coolidge made a tube with leaded glass tube, which served as a radiation shield. Eastman Kodak Company developed a darkroom with processing tanks.
Rollins described collimation, intensifying screens, and the necessity of draping the patient with protective aprons for radiographic examination. Films were packed by machines. Further to this, there was no considerable development in the design of the x-ray equipment. Isaac Asimov A neutron walked into a bar and asked how much for a drink.
The bartender replied, "for you, no charge. Jaime - Internet Chemistry Jokes By convention there is colour, by convention sweetness, by convention bitterness, but in reality there are atoms and space.
Energy results when the state of matter is altered. The fundamental unit of matter is the atom. The atoms can be described as the basic building blocks of matter. The atom consists of a central nucleus and orbiting electrons Fig.
An atom is identified by the composition of its nucleus and the arrangement of its orbiting electrons. The protons and neutrons are collectively called as nucleons. The protons carry positive electrical charge and the neutrons are electrically neutral. The number of protons and neutrons in the nucleus of an atom determines its atomic weight. The number of protons is the same as the number of orbiting electrons and determines the atomic number.
Hydrogen has an atomic number of 1 and hahnium Hn has an atomic number of Electrons are tiny negatively charged particles with negligible mass.
The electrons travel around the nucleus in orbits or shells. These shells represent different energy levels. The number of electrons Fig. The distance between the nucleus and the orbiting electrons determines the binding energy. The electrons in the K shell have a greater binding energy than the electrons in the outer shell.
This binding energy is measured in electron-volts eV or kilo-electron-volts keV. A molecule is the smallest amount of a substance with distinct characteristic properties.
In a molecule the atoms are joined by chemical bonds. Molecules are formed by either the transfer of electrons or by sharing the electrons between the outermost shells of atoms. An atom is referred to as a neutral atom when it contains equal number of protons and electrons. An atom with incompletely filled outer shell is electrically unbalanced and tries to gain electron to achieve a stable state. If an atom gains an electron it will have more negative charge. If an atom loses an electron it will have more positive charge.
An atom, which has gained or lost an electron, is called an ion. Ionization refers to the process of converting an atom into ion. An ion pair is formed when an electron is removed from an atom in the ionization process.
The atom thus becomes a positive ion. This ion pair tries to attain electrically stable state neutral atom by reacting with other ions. Radiation is the emission and propagation of energy through space or a substance in the form of waves or particles. Radioactivity is defined as the process by which certain unstable atoms or elements undergo spontaneous disintegration or decay, in an attempt to attain a more balanced nuclear state. A radioactive substance gives off energy in the form of particles or rays as a result of the disintegration of atomic nuclei.
Ionizing radiation is grouped into the following: a.
Particulate radiation b. Electromagnetic radiation. Particulate Radiation Particulate radiations are tiny particles of matter possessing mass and traveling in straight lines and at high speeds. There are four recognized types of particulate radiation. These are described below. Electrons are the beta particles or cathode rays. Beta particles are fast-moving electrons emitted from the nucleus of Radiation Physics 21 radioactive atoms. Cathode rays are high-speed electrons originating in an x-ray tube.
Alpha particles are emitted from the nucleus of heavy metals and exist as two protons and neutrons, without any electrons. Neutrons are accelerated particles with a mass of 1 and without any electrical charge. Electromagnetic Radiation Electromagnetic radiation is defined as the propagation of wave-like energy without mass through space or matter.
Electromagnetic radiations are either man-made artificial or natural. When the electromagnetic radiations are grouped according to their energies it is called as the electromagnetic spectrum Fig.
The individual radiations of the spectrum differ in their wavelengths and frequencies and also in properties. The waves with shorter wavelengths and higher frequencies have more photon energy.
The energy waves have a crest height of the wave and trough depth of the wave. The distance from one crest to another is called the wavelength or lambda.
Figure represents the crest and trough. The frequency of a wave refers to the number of oscillations per unit of time. The wavelength of x-rays is very short and is measured in angstrom units. Ten billion angstroms equal 1 meter.
The x-rays differ from visible light in the wavelength. If the wavelength is less, the frequency is more and more energy it bears.
Possession of greater energy facilitates penetration of matter. The effects of electromagnetic radiation on human tissues can be summarized as given below: Television and radiowaves: No effect on human tissues. Microwaves low energy radiation : May produce heat within organic tissue. Low energy radiation capable of causing less ionization: As these have low ionization effects on living tissues, they are used in magnetic resonance imaging MRI.
This type of radiation is located near the radiowaves. Gamma rays and X-rays: These rays are capable of causing ionization. X-rays have properties of being both waves and particles particles or photons are bundles of energy without any mass or weight and traveling as waves Fig.
A photon is equivalent to one quantum of energy. The x-ray beam is made up of millions of individual photons. The absorption depends on the atomic structure of matter and the wavelength of the x-rays X-rays cause ionization of matter X-rays can cause certain substances to fluoresce or emit radiation in longer wavelength X-rays can produce image on photographic film X-rays can cause biologic changes in living cells Radiation Physics 25 An electrical and magnetic fields fluctuate perpendicular to the direction of x-rays and at right angles to each other Fig.
This is the fundamental principle of x-ray production. The component parts of the x-ray tube are the following: A leaded-glass housing A negative electrode cathode A positive electrode anode The glass tube is a vacuum tube. Evacuation of the glass tube is done to prevent the loss of kinetic energy of the electrons by colliding with the gas molecules and also to prevent the oxidation burn out of the filament.
Image characteristics Processing of film and image formation Infection control in dental radiography Patient management in dental radiography Section III: Intraoral Techniques Intraoral radiography: Bisecting line angle technique Parallel line angle technique Bitewing radiography Occlusal radiography Specialized intraoral techniques Section IV: Radiographic Interpretation Normal radiographic anatomy Principle of radiographic interpretation Quality control in dental radiography Undiagnostic Radiography Section V: Extraoral Techniques Lateral oblique view Skull radiography Cephalometrics Section VI: Specialized Techniques OPG Computed tomography Magnetic resonance imaging Digital radiography CBCT Ultrasonography Nuclear Medicine Positron emission tomography and Fusion Imaging Image Guided Therapy Radiology of Specific Systems Contrast agents Imaging of Temporomandibular Joint Arthrography and Arthroscopy of TMJ Radiographic Diagnosis of Lesions Teeth Anomalies Periodontal Imaging and Diseases Radiological Aspects of Inflammatory Lesions Dental Caries Cysts of the Jaw Tumours of Jaw