This document discusses common casting defects in dentistry, their causes, and methods to prevent them. It begins by classifying defects and dimensions inaccuracies. It then examines specific defects like distortion, surface roughness, porosities, incomplete castings, and discolored castings. For each defect, it outlines potential causes such as wax pattern issues, improper investments, heating/cooling rates, and gas entrapment. It provides tips to control defects like using the proper water/powder ratio, venting molds, and casting procedures. The conclusion emphasizes that following methods can avoid defects and produce high quality castings for clinical success.
Description :
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Description :
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Dental casting investment: A material consisting primarily of an allotrope of silica and a bonding agent. The bonding substance may be gypsum (for use in lower casting temperatures) or phosphates and silica (for use in higher casting temperatures). (GPT 8)
Dental Ceramics and Porcelain fused to metal isabel
Dental porcelain (also known as dental ceramic) is a dental material used to create biocompatible lifelike dental restorations, such as crowns, bridges, and veneers.
Dental waxes are among the routine laboratory materials used in dentistry. For successful lab procedures it is necessary to amplify the material knowledge.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Dental casting investment: A material consisting primarily of an allotrope of silica and a bonding agent. The bonding substance may be gypsum (for use in lower casting temperatures) or phosphates and silica (for use in higher casting temperatures). (GPT 8)
Dental Ceramics and Porcelain fused to metal isabel
Dental porcelain (also known as dental ceramic) is a dental material used to create biocompatible lifelike dental restorations, such as crowns, bridges, and veneers.
Dental waxes are among the routine laboratory materials used in dentistry. For successful lab procedures it is necessary to amplify the material knowledge.
Indian Dental Academy: will be one of the most relevant and exciting
training center with best faculty and flexible training programs
for dental professionals who wish to advance in their dental
practice,Offers certified courses in Dental
implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic
Dentistry, Periodontics and General Dentistry.
Indian Dental Academy: will be one of the most relevant and exciting
training center with best faculty and flexible training programs
for dental professionals who wish to advance in their dental
practice,Offers certified courses in Dental
implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic
Dentistry, Periodontics and General Dentistry.
Casting defects/certified fixed orthodontic courses by Indian dental academy Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078
Casting defects/cosmetic dentistry course by Indian dental academyIndian dental academy
Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.
this is a presentation that describes the laboratory procedure in RPD framework fabrication
also has a flow chart in the beginning explaining steps to be done by dentist and steps to be taken by laboratory technician
https://youtu.be/aaJ6gpQohcs
https://youtu.be/REMKSUty0cE
https://youtu.be/fv3_tWZPJIU
https://youtu.be/GeZIbCwqKYU
if you want me to make ppt on some topic do let me know on the comment section of my youtube channel
Casting procedures /certified fixed orthodontic courses by Indian dental aca...Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078
Students, digital devices and success - Andreas Schleicher - 27 May 2024..pptxEduSkills OECD
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Bio-prospecting tools for drug discovery,
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Reverse Pharmacology.
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The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
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What is the purpose of the Sabbath Law in the Torah. It is interesting to compare how the context of the law shifts from Exodus to Deuteronomy. Who gets to rest, and why?
The Indian economy is classified into different sectors to simplify the analysis and understanding of economic activities. For Class 10, it's essential to grasp the sectors of the Indian economy, understand their characteristics, and recognize their importance. This guide will provide detailed notes on the Sectors of the Indian Economy Class 10, using specific long-tail keywords to enhance comprehension.
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We all have good and bad thoughts from time to time and situation to situation. We are bombarded daily with spiraling thoughts(both negative and positive) creating all-consuming feel , making us difficult to manage with associated suffering. Good thoughts are like our Mob Signal (Positive thought) amidst noise(negative thought) in the atmosphere. Negative thoughts like noise outweigh positive thoughts. These thoughts often create unwanted confusion, trouble, stress and frustration in our mind as well as chaos in our physical world. Negative thoughts are also known as “distorted thinking”.
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
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Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
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2. Introduction
Classification of defect in casting/common
causes of casting defects
Dimensional Inaccuracies or Dimensional errors in
casting
Distortion
Surface roughness
Contents
15. General
problems
Problems with
internal porosity
Problems with
external porosity
accuracy
distortion
bubbles
fins
short rounded margins
miscasting's
pits
localize shrinkage porosity
subsurface porosity
micro porosity
back pressure porosity
19. Dimensional Inaccuracies or
Dimensional errors in casting
The final fit of a casting depends on a balancing out
of contraction and expansion which occurs during
its construction.
22. The tolerance limit of dental castings are
approximately one tenth the thickness of
human hair.
23. Control of Dimensional accuracy
Use mixing water of correct temperature (usually mouth
temperature)
use constant water powder ratio
For hygroscopic expansion immerse the investment
before it reaches initial set
control time and temperature
cast into the heated mould while it is still at the correct
temperature.
32. The surface of a dental casting
should be an accurate
reproduction of the surface of the
wax pattern from which it is made
33. Definition: Relatively finely spaced surface
imperfections whose height, width and
direction establish the predominant surface
pattern.
34.
35. • Improper finishing of wax pattern
• Improper water powder ratio
• Excess surfactant
• Direct wax pattern
• Raid heating rates
• Underheating
• Too high a pressure during casting
• Composition of investment
• Foreign bodies
• Impact of molten alloy
• Pattern position
39. Before starting to invest a direct wax pattern taken from
the mouth it should be washed in water
40. Mold should be heated gradually, at least 60
min should elapse during the heating of the
investment filled ring from room temperature to
700ºC.
A gauge pressure of 0.10 to 0.14 MPa in air pressure casting machine or 3 to 4 turns of the
spring in an average type of centrifugal casting machine is sufficient for small casting.
42. Bubbles of gases trapped between the wax
pattern and the investment produce nodules
on the casting surface.
43. Large nodule- Air trapped during investing
Multiple nodules – Inadequate vacum during mixing
Improper brush technique
Lack of surfactant.
Nodules on occlusal surface –
Prolonged vibration after pouring
55. The temperature of the alloy should be raised higher than its liquidus temperature
Adequate venting the mold
Sufficiently high casting pressure
Accurate W/P ratio
Use large sprue former
Mold should soak heat approximately 1 hour at burnout temperature.
Mold should be removed from burn out oven and cast immediately
Ensure that no debris blocks the ingate
Cast enough metal
57. Localized shrinkage porosity
caused by premature termination of the
flow of the molten metal during
solidification. The linear contraction of
noble metal alloys - changing from a
liquid to solid in at least 1.25%.
58. • Improper sprue design causes suck back
porosity.
• The entering metal impinges onto the mold
surface and creates a higher localized mold
temperature in this region known as Hot
spot.
• Hot spot may retain a localized pool of
molten metal after area have solidified
causing shrinkage void or suck back porosity.
Suck back porosity
59.
60. Simultaneous nucleation of solid grains and
gas bubbles at the first movement that the
alloy freezer at the mold walls.
Subsurface porosity
caused
Can be diminished by controlling the rate at which the molten metal enters the mold.
62. Since back pressure porosity occurs more generally in full crown type
castings, insertion of a wax rod into the core of the investment when
investing the pattern will provide a good means of venting the hot gases
quickly
68. Using more metal when casting so that a good
size button is left us a important precaution.
69. Hygroscopic low burn out technique produces more
of this porosity than high heat techniques.
70. CONCLUSION
Thus, these are the various causes for the failure of the
castings and methods by which these defects can be
avoided, thereby producing a casting of good quality
for clinical success.
71. REFERENCES
Operative Dentistry Modern theory and practice-Marzouk
Dental materials – Philiphs – Anusavice
Full mouth rehabilitation – Kornfield
Restorative Dental materials – Craig
72. Fixed prosthodontics – Rosenstiel
Fundamentals of fixed prosthodontics – Schillinburg.
Australian Dental Journal 1991 36 (5): 391-6
1992 37(1) 93-54
1991 36(4): 302-9
1992 37 (2): 91-7
Notes on Dental Materials – E.C. Coombe
British Dental Journal 1972: 428-435.