The document discusses impression materials and gypsum products used in dentistry. It defines impression materials as negative records of oral tissues used to create positive dental casts. Desirable properties include accuracy, strength, and compatibility. Common materials discussed are impression compound, zinc oxide-eugenol, and elastomeric materials. Gypsum products set from a fluid mix and are used to fabricate casts from impressions. Factors like water-powder ratio and temperature control setting times.
A dental impression is a negative imprint of hard (teeth) and soft tissues in the mouth from which a positive reproduction (cast or model) can be formed. It is made by placing an appropriate material in a stock or custom dental impression tray which is designed to roughly fit over the dental arches.
A IDEA ABOUT IMPRESSION MATERIALS OF PROSTHODONTICS. I STUDY ABOUT IMPRESSION MATERIALS & MAKE THIS PPT . I THINK IT WILL BE HELPFUL TO STUDENTS OF UNDERGRADUATE IN PRE-CLINICAL STUDY.
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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.
A dental impression is a negative imprint of hard (teeth) and soft tissues in the mouth from which a positive reproduction (cast or model) can be formed. It is made by placing an appropriate material in a stock or custom dental impression tray which is designed to roughly fit over the dental arches.
A IDEA ABOUT IMPRESSION MATERIALS OF PROSTHODONTICS. I STUDY ABOUT IMPRESSION MATERIALS & MAKE THIS PPT . I THINK IT WILL BE HELPFUL TO STUDENTS OF UNDERGRADUATE IN PRE-CLINICAL STUDY.
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.
Impression materials for complete denture/certified fixed orthodontic courses...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.
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Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078
Impression materials/dental implant courses 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.
agar agar and alginate impression materialsRenu710209
agar and alginate are the most commnly used impression material in dentistry for recording impression of the dental arches and for duplication of teeth and associated structures.
agar agar and alginate impression materialsRenu710209
agar and alginate are the most commnly used impression material in dentistry for recording impression of the dental arches and for duplication of teeth and associated structures.
Impression material are used to register or reproduce the form and the relationship of the teeth and the oral tissue, the area involved may vary from a single tooth to the whole dentition, or an impression may be made of an edentulous mouth.
Hydrocolloids and synthetic elastomeric polymer are among the materials most commonly used to make impressions of various areas of the dental arch.
Recent advances in dental materials certified fixed orthodontic courses by In...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
Impression materials/ rotary endodontic courses 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.
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
Recent advances in dental materials/dental crown &bridge course by Indian den...Indian 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.
Impression materials for complete denture/certified fixed orthodontic courses...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
Impression materials/dental implant courses 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.
agar agar and alginate impression materialsRenu710209
agar and alginate are the most commnly used impression material in dentistry for recording impression of the dental arches and for duplication of teeth and associated structures.
agar agar and alginate impression materialsRenu710209
agar and alginate are the most commnly used impression material in dentistry for recording impression of the dental arches and for duplication of teeth and associated structures.
Impression material are used to register or reproduce the form and the relationship of the teeth and the oral tissue, the area involved may vary from a single tooth to the whole dentition, or an impression may be made of an edentulous mouth.
Hydrocolloids and synthetic elastomeric polymer are among the materials most commonly used to make impressions of various areas of the dental arch.
Recent advances in dental materials certified fixed orthodontic courses by In...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
Impression materials/ rotary endodontic courses 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.
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
Recent advances in dental materials/dental crown &bridge course by Indian den...Indian 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.
Prix Galien International 2024 Forum ProgramLevi Shapiro
June 20, 2024, Prix Galien International and Jerusalem Ethics Forum in ROME. Detailed agenda including panels:
- ADVANCES IN CARDIOLOGY: A NEW PARADIGM IS COMING
- WOMEN’S HEALTH: FERTILITY PRESERVATION
- WHAT’S NEW IN THE TREATMENT OF INFECTIOUS,
ONCOLOGICAL AND INFLAMMATORY SKIN DISEASES?
- ARTIFICIAL INTELLIGENCE AND ETHICS
- GENE THERAPY
- BEYOND BORDERS: GLOBAL INITIATIVES FOR DEMOCRATIZING LIFE SCIENCE TECHNOLOGIES AND PROMOTING ACCESS TO HEALTHCARE
- ETHICAL CHALLENGES IN LIFE SCIENCES
- Prix Galien International Awards Ceremony
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
Report Back from SGO 2024: What’s the Latest in Cervical Cancer?bkling
Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
Acute scrotum is a general term referring to an emergency condition affecting the contents or the wall of the scrotum.
There are a number of conditions that present acutely, predominantly with pain and/or swelling
A careful and detailed history and examination, and in some cases, investigations allow differentiation between these diagnoses. A prompt diagnosis is essential as the patient may require urgent surgical intervention
Testicular torsion refers to twisting of the spermatic cord, causing ischaemia of the testicle.
Testicular torsion results from inadequate fixation of the testis to the tunica vaginalis producing ischemia from reduced arterial inflow and venous outflow obstruction.
The prevalence of testicular torsion in adult patients hospitalized with acute scrotal pain is approximately 25 to 50 percent
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New Drug Discovery and Development .....NEHA GUPTA
The "New Drug Discovery and Development" process involves the identification, design, testing, and manufacturing of novel pharmaceutical compounds with the aim of introducing new and improved treatments for various medical conditions. This comprehensive endeavor encompasses various stages, including target identification, preclinical studies, clinical trials, regulatory approval, and post-market surveillance. It involves multidisciplinary collaboration among scientists, researchers, clinicians, regulatory experts, and pharmaceutical companies to bring innovative therapies to market and address unmet medical needs.
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
Couples presenting to the infertility clinic- Do they really have infertility...Sujoy Dasgupta
Dr Sujoy Dasgupta presented the study on "Couples presenting to the infertility clinic- Do they really have infertility? – The unexplored stories of non-consummation" in the 13th Congress of the Asia Pacific Initiative on Reproduction (ASPIRE 2024) at Manila on 24 May, 2024.
4. Definition
A dental impression material is a negative record of the tissue of the
mouth.
The negative reproduction of the tissue given by the impression material
is filled up with dental stone or other model materials to get a positive
cast.
it is used to
reproduce the form
the teeth and the
surrounding
tissues.
6. Die is The positive reproduction of a single tooth
cast or model it is when several teeth or a whole
of the arch is reproduced , called
7. Advantages of using a cast or model
1) models provide a
three-dimensional view
of the oral structures .
2)Many restorations or
appliance are best
constructed on a cast.
3) Saving valuable
clinical time
9. Desirable properties of an impression materials
Biocompatible to the dentist and patient
Acceptable to the patient
Have a pleasant taste , odor, consistency and color
Should set quickly once placed in the mouth
Accurate surface detail
Manipulation should be easy
12. Impression tray
impression tray:
Is The metallic or plastic carrier ,which are use to take
impression of natural teeth & their supporting oral
tissues by the impression materials
13. Impression compound
Impression compound :is
one of the oldest impression
materials .
It can be described as rigid,
reversible impression
material which sets by
physical change on heat.
On a applied heat ,it softens
and on cooling it hardens.
14. cont’s
it is mainly used for making impressions of
edentulous ridges.
modeling compound or modeling plastic
17. Indications
1. used for taking primary
impressions of the edentulous
ridge prior to the construction
of a custom-made impression
tray for complete dentures.
2. Bite registration
Giordano, Gen Dent 2000
18. Requirements of ideal impression compound
be plastic
Biocompatible
Harden uniformly when cooled with out distortion
Exhibit a smooth glossy surface after flaming
Withstand trimming
Should not boil
19. manipulation
Sticks:
Small amount of compound (stick compound) can be softened
over a flame .
Cakes:
Larger amounts of compound are softened in warm water in a
thermostatically controlled water path.
21. Loading the tray:
The softening is loaded onto the tray and quickly
seated on to the tissue to be recorded.
Any delay can cause
the impression to harden prematurely.
22. Precautions
Prolonged impression in water path causes the
compound to become brittle.
overheating in water makes the compound sticky
and difficult to handle.
the impression is removed from the mouth only
after it has completely cooled and hardened.
Then disinfect the compound.
24. Advantages of the compound
The material can be reused a number of times.
accuracy can be improved by flaming the surface.
The material has sufficient body to support itself especially
peripheral portions.
25. Disadvantages
Records less detail because of its high viscosity.
compresses soft tissue during impression.
Distortion due to its poor dimensional stability
Difficult removing if the there are severe undercuts.
27. Indications Zinc oxide-eugenol
1. Temporary filling
2. Temporary cementation
3. Root canal filling material
4. For full arch edentulous impression
without or minor undercut
5. Bite registration
29. Manipulation
Equal length of the two paste is extruded
Mixed with stainless steel spatula in paper
pad or glass slab
Mixing time 45-60 s
Working time 3-5 min
30. Non-Eugenol Pastes
NON-EUGENOL PASTE: developed to overcome
the burning sensation caused by eugenol .
Used in eugenol irritant patients
31. Elastomeric Impression Materials
A material that is used when an extremely accurate
impression is essential.
The term elastomeric means having elastic or rubberlike
qualities.
35. Irreversible Hydrocolloid
Material that cannot return to a solution state after it
becomes a gel.
Alginate :
is the irreversible hydrocolloid most widely used for
preliminary impressions.
39. Non-aqueous elastomers
They are soft and rubber like and far more stronger
and stable than the hydrocolloids.
They are liquid polymers which can be converted to
solid rubber at room temperature.
These materials are most accurate and dimensionally
stable impression materials available in dentistry.
42. Supplied as
Base and catalyst
GENERAL PROPERTIES OF ELASTOMERIC MATERIALS
Excellent reproduction of surface details
They are generally hydrophobic
Coefficient of thermal expansion is high
The shelf life is two years
43. How you can Control of gagging?
1) seat the patient in an upright position.
2) rinse cold water or mouthwash before impression is
made.
3) The impression tray should not be overfilled with
impression material.
44. 4) The posterior portion of the impression tray
should be seated first. Then, the anterior portion
of the tray should be rotated into position. this
permits excess impression material to be
displaced in an anterior direction away from the
soft plate and airway.
45. Cont’s
5. The patient should be instructed to keep the
eyes open during the impression producer.
6. The patient should be directed to breath
through the nose. the dentist should encourage
slow, deep breaths.
7.use topical /spray anaesthesia to numb the area
47. is a naturally occurring, white powdery mineral with the
chemical name calcium sulphate dehydrate (CaSQ4·2H2O).
Their main uses are for:
◦ casts or models
◦ Dies
◦ investments
Gypsum:
48. Conti…….
models and dies should be accurate replicas of the
patient’s hard and soft tissues.
models and dies are prepared
using materials which are initially
fluid and can be poured into the
impression, then harden to form a
rigid replica.
49. Requirements of dental cast materials:
dimensional accuracy
adequate mechanical properties
be fluid at the time it is poured
be sufficiently strong to resist accidental fracture and
abrasion
be compatible with all the other materials with which it
comes into contact
50. Manipulation and setting characteristics
Plaster and stone powders are mixed with water to
produce a workable mix.
(CaSO4)⋅H2O+3H2O→2CaSO4⋅2H2O
Calcium sulphate hemihydrate + water
Calcium sulphate dihydrate
51. Considerable quantities of air may be incorporated
during mixing and this may lead to porosity within the
set material.
Air porosity may be reduced either by:
◦ vibrating the mix in order to bring air bubbles to the
surface
52. For hand mixing u need:
◦ clean rubber or plastic
bowl
◦ spatula
53. Factors which control the setting times of gypsum products can be divided
into:
1)controlled by manufacturers:
the concentration of nucleating agents in the hemihydrate powder
Chemical accelerator
2)controlled by the operator:
Temperature
W/P ratio
mixing time
Control of setting time:
A material that is used when an extremely accurate impression is essential. The term elastomeric means having elastic or rubberlike qualities.
Hydrocolloid impression materials
Hydro means water.
Colloid means gelatin substance.
Material used to obtain preliminary and final impressions.
The two types of hydrocolloids used in dental impressions are agar and alginate. Agar is a reversible hydrocolloid because it can pass
repeatedly between highly viscous gel and low viscosity sol simply through heating and cooling.
However, alginate once converted to the gel form cannot be converted back into the sol, and is therefore said to be irreversible hydrocolloid material.
Agar and alginate may be used independently or in combination to record crown impressions.
Agar was first introduced into dentistry for recording crown impressions in 1937 by Sears1 and was the first elastic impression material available.
It is not commonly used in dental practice today however, because of the need for expensive conditioning baths and water cooled
trays.
Alginate, unlike agar, does not require any special equipment. Being easy to use and inexpensive it is popular for less critical applications
Eg. Apposing casts and study models.
Alginate and agar produce impressions with reasonable surface detail. They are both relatively hydrophilic and are not displaced from wet surfaces as easily as the elastomers2.
However, in respect of recording crown preparations these materials have two major disadvantages.
Firstly, very poor dimensional stability because of the ready loss or imbibition of water on standing in dry or wet environments
respectively.
Secondly, low tear resistance which can be a real problem when attempting to record the gingival sulcus.
Some work supports the use of combined reversible and irreversible hydrocolloid impression systems.3,4
These systems are used in a way similar to the putty-wash technique for silicone rubbers described later in this article, with the agar injected around the preparation to capture surface detail and the more viscous alginate in the impression tray.
The advantages of this combination system compared with agar or alginate used individually is the minimisation of equipment required to record an agar impression (no water cooled tray is needed) and the fact that agar is more compatible with gypsum model materials than
alginate. It is also relatively cheap in comparison to many synthetic elastomers. Lin et al.5 demonstrated that the accuracy of this combination system is better than either the reversible or irreversible materials used separately and is comparable to that of polysulphide impression materials. However, the problems of low tear resistance and poor dimensional stability still apply resulting in the need for impressions to be cast up immediately.
For these reasons, most practitioners tend to reject the hydrocolloids in favour of the synthetic elastomers to produce accurate
and stable impressions.