piden midterms

• Inventions and Discoveries

  Porcelain Pontics

  Amalgam Fillings

  Dental X-ray

  Anesthesia: Dental Engine
• Amalgam Fillings

  It is an alloy made by mixing mercury (Hg) with a silver (Ag) tin (Sn) alloy.
• Dental amalgam alloy is a silver tin alloy to which varying amount of copper and small amount of zinc has been added
• According to Skinner’s, amalgam is a special type of alloy in which one of its constituents is mercury.
• In dentistry, it is common to use the term amalgam to mean dental amalgam.
• Dental Amalgam is first used by Chinese.
• There is a mention of silver mercury paste by Sukung (659 A.D.) in the Chinese medic.
• In 1578, lshitichen used 100 parts of Hg, 45 parts of Ag and 100 parts of Sn.
• In 1800s, introduced in France an alloy of bismuth (Bi), lead (Pb), tin (Sn) and mercury (Hg) plasticized at 100 “C poured directly into cavity.
• During 1819 in England, Bell advocated the use of a room temperature mixed amalgam as a restorative material.
• During 1836, in France, M. Traveau is credited with advocating the first form of amalgam paste.
• In 1833, Crawcours Brothers introduced amalgam to U.S.
• In 1895, to ovcercome expansion problems of amalgam, G.V. Black developed a formula:

  67% silver

  27% tin

  5% copper

  1% zinc
• 1890 - 1963 - GV Black’s formula was well accepted and not much changed for nearly sixty years
• In 1946, Skinner added copper (Cu) to the amalgam alloy composition in a small amount.
• In 1971, Johnson designed a spherical particle alloy with composition of:

  64% silver

  26% tin

  10% copper
• 1973 - first single composition spherical alloy named Tytin (Kerr) a ternary system (silver/tin/copper) was discovered by Kamal Asgar of the University of Michigan
• During 1980’s, alloys similar to Dispersalloy and Tytin was introduced.
• Liu Wen-Thai (1508) and Li Shih-Chen (1578) discussed its formulation; 100 parts of mercury to 45 parts of silver and 90 parts of tin, trituration of these ingredients produced a paste said to be as solid as silver
• Silver (Ag)

  Constitutes approximately 2/3rd of conventional amalgam alloy.
• Tin (Sn)

  Second largest component and contributes 1⁄4 of amalgam alloy.
• Gama-2 phase

  which is the weakest phase and contributes to failure of amalgam restoration.
• Copper

  Contributes mainly hardness and strength.
• Zinc (Zn)

  acts as Scavenger of foreign substances such as oxides.
• Indium (In)/Palladium (Pd):

  They help to increase the plasticity and the resistance to deformation.
• 1845 - first amalgam war
• 1920 - second amalgam war
• 1980 - third amalgam war
• Dr. Huggins - a practicing dentist in Colorado. He was convinced that mercury released from dental amalgam was responsible for human diseases affecting the cardiovascular system and nervous system.
• Dental Radiograph

  It is a radiographic procedure that is used or employed to take images of the teeth, bones, and soft tissues around them, in order to identify, diagnose, plan treatments and monitor both treatments and lesion development.
• The Radiographers practicing dental radiography are called Dental Radiographers and provide dental images/radiographs for the dentist.
• The first dental clinic was established by Dr. C.E. Kells in July 1896, using Xray machine.
• Intra - Oral Radiography - Bitewing

  Detection or monitoring of interproximal caries if the surface is cannot visually examine.
• Extra-Oral Radiography: Oblique Lateral Radiograph

  An extra-oral radiograph that can be taken using a dental x-ray set which will allow visualization of the posterior teeth, angle, ramus, and condyle of the mandible and posterior maxilla.
• Extra-Oral Radiography: Cone Beam Computed Tomography (CBCT)

  The use of CBCT is valuable adjunct in assessing and diagnosing pathology in endodontics, oral pathology, anomalies of the developing dentition.

   
• Tube Head

  This tube emits radiation in the form of photons. X-ray photons expose the film.
• Extension Arm

  It is attached to the metal extension arm by means of a yoke that can revolve 360 degrees horizontally where it is connected
• Cylinder (Cone)

  It is affixed to the tube head and is used to align the tube head with the patient and x-ray.

   
• The components of the control panel are switches, dials, gauges, and lights.
• After making the exposure, process the X-ray film.