1. Ceramic strengthening techniques aim to reduce tensile stresses by introducing compressive stresses. Methods include dispersion strengthening by adding crystalline particles, metal bonding, thermal tempering, and ion exchange.
2. Proper design and fabrication techniques are important to maximize ceramic strength. These include adequate thickness, rounded line angles, sufficient occlusal reduction, and controlling stresses from bonding cement.
3. Newer high-strength ceramics like zirconia use phase transformations to toughen the material. Stresses from the monoclinic to tetragonal phase change on cooling inhibit crack propagation.
Introduction
CERAMICS : An inorganic compound with non-metallic prosthesis typically consisting of oxygen and one or more metallic or semi-metallic elements that is formulated to produce the whole part of a ceramic based dental prosthesis. – GPT 7.
The word Ceramic is derived from the Greek word “keramos”, which literally means ‘burnt stuff’, but which has come to mean more specifically a material produced by burning or firing.
An inlay may cap none, or may cap all but one cusp.
Sturdevant’s 4th ed. page579
Inlays may be used as single-tooth restorations for proximo-occlusal or gingival lesions with minimal to moderate extensions
Shillingburg page 1
An inlay may be defined as a restoration which has been constructed out of mouth from gold, porcelain, or other material & then cemented into the prepared cavity of a tooth.
William McGehee pg410
direct filling gold... material aspect, types, condensation, cavity design, modifications. detaied seminar for post gradutes.... any doubts or suggestions contact dr.mb@hotmail.com
Introduction
CERAMICS : An inorganic compound with non-metallic prosthesis typically consisting of oxygen and one or more metallic or semi-metallic elements that is formulated to produce the whole part of a ceramic based dental prosthesis. – GPT 7.
The word Ceramic is derived from the Greek word “keramos”, which literally means ‘burnt stuff’, but which has come to mean more specifically a material produced by burning or firing.
An inlay may cap none, or may cap all but one cusp.
Sturdevant’s 4th ed. page579
Inlays may be used as single-tooth restorations for proximo-occlusal or gingival lesions with minimal to moderate extensions
Shillingburg page 1
An inlay may be defined as a restoration which has been constructed out of mouth from gold, porcelain, or other material & then cemented into the prepared cavity of a tooth.
William McGehee pg410
direct filling gold... material aspect, types, condensation, cavity design, modifications. detaied seminar for post gradutes.... any doubts or suggestions contact dr.mb@hotmail.com
Silver amalgam is undoubtedly the most commonly used restorative material.
If amalgam is manipulated properly and used, it is still one of the best dental restorative material where its indicated
The average life span of an amalgam restoration is upto 8-10 yrs if manipulated correctly.
Howerver many amalgam restorations fail in function, mainly due to iatrogenic factors and can be avoided by careful attention to all the details during preparation and placement of amalgam restorations
This presentation explains various reasons for the amalgam restoration to fail in the oral cavity
Description :
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Rasamanikya is a excellent preparation in the field of Rasashastra, it is used in various Kushtha Roga, Shwasa, Vicharchika, Bhagandara, Vatarakta, and Phiranga Roga. In this article Preparation& Comparative analytical profile for both Formulationon i.e Rasamanikya prepared by Kushmanda swarasa & Churnodhaka Shodita Haratala. The study aims to provide insights into the comparative efficacy and analytical aspects of these formulations for enhanced therapeutic outcomes.
share - Lions, tigers, AI and health misinformation, oh my!.pptxTina Purnat
• Pitfalls and pivots needed to use AI effectively in public health
• Evidence-based strategies to address health misinformation effectively
• Building trust with communities online and offline
• Equipping health professionals to address questions, concerns and health misinformation
• Assessing risk and mitigating harm from adverse health narratives in communities, health workforce and health system
Local Advanced Lung Cancer: Artificial Intelligence, Synergetics, Complex Sys...Oleg Kshivets
Overall life span (LS) was 1671.7±1721.6 days and cumulative 5YS reached 62.4%, 10 years – 50.4%, 20 years – 44.6%. 94 LCP lived more than 5 years without cancer (LS=2958.6±1723.6 days), 22 – more than 10 years (LS=5571±1841.8 days). 67 LCP died because of LC (LS=471.9±344 days). AT significantly improved 5YS (68% vs. 53.7%) (P=0.028 by log-rank test). Cox modeling displayed that 5YS of LCP significantly depended on: N0-N12, T3-4, blood cell circuit, cell ratio factors (ratio between cancer cells-CC and blood cells subpopulations), LC cell dynamics, recalcification time, heparin tolerance, prothrombin index, protein, AT, procedure type (P=0.000-0.031). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and N0-12 (rank=1), thrombocytes/CC (rank=2), segmented neutrophils/CC (3), eosinophils/CC (4), erythrocytes/CC (5), healthy cells/CC (6), lymphocytes/CC (7), stick neutrophils/CC (8), leucocytes/CC (9), monocytes/CC (10). Correct prediction of 5YS was 100% by neural networks computing (error=0.000; area under ROC curve=1.0).
Adv. biopharm. APPLICATION OF PHARMACOKINETICS : TARGETED DRUG DELIVERY SYSTEMSAkankshaAshtankar
MIP 201T & MPH 202T
ADVANCED BIOPHARMACEUTICS & PHARMACOKINETICS : UNIT 5
APPLICATION OF PHARMACOKINETICS : TARGETED DRUG DELIVERY SYSTEMS By - AKANKSHA ASHTANKAR
These lecture slides, by Dr Sidra Arshad, offer a quick overview of the physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar lead (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
6. Describe the flow of current around the heart during the cardiac cycle
7. Discuss the placement and polarity of the leads of electrocardiograph
8. Describe the normal electrocardiograms recorded from the limb leads and explain the physiological basis of the different records that are obtained
9. Define mean electrical vector (axis) of the heart and give the normal range
10. Define the mean QRS vector
11. Describe the axes of leads (hexagonal reference system)
12. Comprehend the vectorial analysis of the normal ECG
13. Determine the mean electrical axis of the ventricular QRS and appreciate the mean axis deviation
14. Explain the concepts of current of injury, J point, and their significance
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. Chapter 3, Cardiology Explained, https://www.ncbi.nlm.nih.gov/books/NBK2214/
7. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
Basavarajeeyam is an important text for ayurvedic physician belonging to andhra pradehs. It is a popular compendium in various parts of our country as well as in andhra pradesh. The content of the text was presented in sanskrit and telugu language (Bilingual). One of the most famous book in ayurvedic pharmaceutics and therapeutics. This book contains 25 chapters called as prakaranas. Many rasaoushadis were explained, pioneer of dhatu druti, nadi pareeksha, mutra pareeksha etc. Belongs to the period of 15-16 century. New diseases like upadamsha, phiranga rogas are explained.
- Video recording of this lecture in English language: https://youtu.be/kqbnxVAZs-0
- Video recording of this lecture in Arabic language: https://youtu.be/SINlygW1Mpc
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
NVBDCP.pptx Nation vector borne disease control programSapna Thakur
NVBDCP was launched in 2003-2004 . Vector-Borne Disease: Disease that results from an infection transmitted to humans and other animals by blood-feeding arthropods, such as mosquitoes, ticks, and fleas. Examples of vector-borne diseases include Dengue fever, West Nile Virus, Lyme disease, and malaria.
Antimicrobial stewardship to prevent antimicrobial resistanceGovindRankawat1
India is among the nations with the highest burden of bacterial infections.
India is one of the largest consumers of antibiotics worldwide.
India carries one of the largest burdens of drug‑resistant pathogens worldwide.
Highest burden of multidrug‑resistant tuberculosis,
Alarmingly high resistance among Gram‑negative and Gram‑positive bacteria even to newer antimicrobials such as carbapenems.
NDM‑1 ( New Delhi Metallo Beta lactamase 1, an enzyme which inactivates majority of Beta lactam antibiotics including carbapenems) was reported in 2008
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
Basavarajeeyam is a Sreshta Sangraha grantha (Compiled book ), written by Neelkanta kotturu Basavaraja Virachita. It contains 25 Prakaranas, First 24 Chapters related to Rogas& 25th to Rasadravyas.
DISSERTATION on NEW DRUG DISCOVERY AND DEVELOPMENT STAGES OF DRUG DISCOVERYNEHA GUPTA
The process of drug discovery and development is a complex and multi-step endeavor aimed at bringing new pharmaceutical drugs to market. It begins with identifying and validating a biological target, such as a protein, gene, or RNA, that is associated with a disease. This step involves understanding the target's role in the disease and confirming that modulating it can have therapeutic effects. The next stage, hit identification, employs high-throughput screening (HTS) and other methods to find compounds that interact with the target. Computational techniques may also be used to identify potential hits from large compound libraries.
Following hit identification, the hits are optimized to improve their efficacy, selectivity, and pharmacokinetic properties, resulting in lead compounds. These leads undergo further refinement to enhance their potency, reduce toxicity, and improve drug-like characteristics, creating drug candidates suitable for preclinical testing. In the preclinical development phase, drug candidates are tested in vitro (in cell cultures) and in vivo (in animal models) to evaluate their safety, efficacy, pharmacokinetics, and pharmacodynamics. Toxicology studies are conducted to assess potential risks.
Before clinical trials can begin, an Investigational New Drug (IND) application must be submitted to regulatory authorities. This application includes data from preclinical studies and plans for clinical trials. Clinical development involves human trials in three phases: Phase I tests the drug's safety and dosage in a small group of healthy volunteers, Phase II assesses the drug's efficacy and side effects in a larger group of patients with the target disease, and Phase III confirms the drug's efficacy and monitors adverse reactions in a large population, often compared to existing treatments.
After successful clinical trials, a New Drug Application (NDA) is submitted to regulatory authorities for approval, including all data from preclinical and clinical studies, as well as proposed labeling and manufacturing information. Regulatory authorities then review the NDA to ensure the drug is safe, effective, and of high quality, potentially requiring additional studies. Finally, after a drug is approved and marketed, it undergoes post-marketing surveillance, which includes continuous monitoring for long-term safety and effectiveness, pharmacovigilance, and reporting of any adverse effects.
Muktapishti is a traditional Ayurvedic preparation made from Shoditha Mukta (Purified Pearl), is believed to help regulate thyroid function and reduce symptoms of hyperthyroidism due to its cooling and balancing properties. Clinical evidence on its efficacy remains limited, necessitating further research to validate its therapeutic benefits.
5. Griffith flaws
They are minute submicroscopic surface
defects (scratches and cracks) present on the
glass surface and act as stress concentration
centers when subjected to tensile stresses
6. •Possible causes of ceramic
surface micro-cracks:
•CTE Mismatches between veneer and
core porcelains.
•Heat generation during grinding and
adjustment .
•the destructive, repetitive masticatory
force that occurs in the oral cavity.
7. Compressive forces
In case of tensile forces, the
forces tend to open crack
sites, resulting in crack
propagation
Compressive
forces, however, tend to
approximate the edges of
surface cracks
Tensile forces
8.
9. •These imperfections may result
from:
Incomplete fusion of particles during
sintering due to improper Firing time or
temperature
If one crystal is out of line or twisted as
compared to its neighbor, the bonds between
them may be stretched or distorted causing
weakness of ceramic structure.
10. Ions of the same charge (positive or negative)
may cause electrostatic repulsion leading to
stresses in this region and finally cracks may
occur.
11. The sizes and shapes of porcelain
particles can be an important factor;
12. Thermal stresses which may develop
during cooling can create internal
flaws, causing the fused porcelain
particles to separate at their interface
porosity .
13.
14. •Fatigue refers to the
degradation of strength over time.
• Clinically, ceramic crowns must
function in the presence of
moisture, externally from saliva and
internally from a cementing agent
.
• Two types of loading
conditions can lead to fatigue:
Cyclic (repetitive) loading & static
loading. In the oral
environment, there is a combination
of both conditions.
15. •The possible mechanism of
ceramic’s fatigue:
I. a chemical reaction between water
molecules and glass surfaces .
II. The absorbed moisture lowers the
energy required for crack
propagation .The pre-existing flaws
grow to critical dimensions.
III. Since stress concentration increases
with length, crack propagation
continues until the load is removed or
fracture occurs.
19. PFM
System
Fusing the porcelain to
an oxide coated metal
provides rigid support
against propagation of
ceramic surface cracks
when
exposing
to
tensile stresses
•The currently used metal-ceramic systems:
i. Nobel metal alloy systems: high gold, low gold and gold
free
Ii`Base metal alloy systems: Ni-Cr, Ti
23. Application of opaquer layer (2 layers) with a
brush and then, firing
After ceramic veneering, firing and finishing
24. Success of Metal-ceramic systems depends
on a strong bond between the metal and
fused ceramic which can be;
•Mechanical Interlocking: the roughened
alloy surface produced by sandblasting
provides irregularities into which porcelain
can flow.
•Van der Waal forces or "wetting bonds”
Depends on surface tension of porcelain in
the liquid state (its contact angle and
wettability)
25. A contact angle greater than 90 degrees
indicates a lack of wetting
and, consequently, lack of adhesion .
26.
27. • External surface compression :
thermal expansion coefficient [CTE] of
the veneered porcelain must be slightly less
than
that
of the metal
alloy. During
cooling, the porcelain is held in a state of
compression as shrinkage of the metal
occurs.
Chemical bonding:
through the oxide layer at porcelain-metal
interface a chemical bonding between the
porcelain to metal occurs.
28. •For precious metal ceramic bond:
Bonded tin foil: platinum foils are electroplated
with a layer of tin oxide to which aluminous
ceramic is attached
•For Base metal ceramic bond:
Base metals can form oxides on their surface
through an oxidative firing
29. 1.Inadequate esthetic, this can be due to:
1. loss of translucency found in natural teeth. In
addition, the underlying metal color often
penetrates the porcelain making it appear
grayer than the surrounding teeth .
30. 2. Opaque porcelains are used
to mask the metal coping;
however,
they
are
highly
reflective causing a less than
natural appearance . In an
attempt
to
avoid
this
reflection,
metal-ceramic
restorations
are
often over
contoured.
2. Galvanism .
3.allergic reactions
in the gingiva.
31. An all-ceramic
restoration in which
crown is bonded to the
underlying dentin and
Dentin bonded
any available enamel
ceramics
using a composite
resin–based luting
material
This method reinforces the ceramic structure
with no need to internal strengthening
mechanisms.
32. The bond is mediated through;
1.Mechanical interlocking; through
sandblasting and etching [a hills and valleys
microscopic appearance]. When the resin flows
over the etched surface, it flows into surface
imperfections, and when the resin hardens, the
imperfections act as undercuts firmly bonding the
resin in place.
2.Chemical bond; through application of silane
coupling agent which bonds through the Si
molecule to the silica in the porcelain and to the
acrylic bonding agents in restoration.
33. Technique
The internal surface of the
sandblasted crown is etched
with hydrofluoric acid
After etching ,The crown is
opaque white.
Silane is applied to the crown
34. A gingival retraction cord is
placed.
The adjacent teeth are
protected with Teflon tape.
The tooth is etched with 37%
phosphoric acid.
35. resin cement is applied
gingival retraction cord is
removed
Final result
36. LUMINEERS
A veneering
system which
can be fabricated
so thin that tooth
reduction is not
usually
necessary.
Its structure and manufacturing resemble that
of EMPRESS I.
37. •How do Lumineers differ from traditional
porcelain veneers?
•They are thinner. The typical Lumineers will
measure on the order of 0.2 to 0.3 mm thick while
the traditional veneer’s thickness ranged from 0.4
to 0.8mm.
•This decreased thickness means that a dentist can
bond an ultra-thin Lumineer directly to an
unprepared tooth, without creating an end result
that is grossly over contoured.
•Lumineers ® can be placed using a "no drilling /
no shots [anesthesia]" protocol.
38. •Disadvantages:
•Poor esthetic as the little amount of opaquer
is unable to mask the tooth shade.
• over contoured or look too toothy: if nodrilling technique is applied.
39. •Indications:
•The patient demands a no-drilling placement
process: ex; people with dental phobias.
•The patient demands a totally reversible
procedure: using a no-drilling technique offers the
possibility that they can be removed if the patient
is unhappy with the appearance they have
created
.
•(In-between visits to avoid the problems
associated with appearance, roughness, or thermal
sensitivity.)
41. When a tough, crystalline material such as alumina
(Al2O3) is added to a glass, the glass is toughened
and strengthened, because the crack cannot pass
through the alumina particles as easily as it can
pass through the glass matrix.
42. •The magnitude of increased strength
depends on:
the
crystal type; toughness and their
geometrical shape.
crystal size; small crystals are better.
the inter-particle spacing; close approximation
is better
relative CTE to the glass matrix as a close
match between the CTE of crystalline material
and the surrounding glass matrix increases
45. I. Thermal tempering:
• rapidly cooling the glass
surface while the center is
hot and in the molten state
produces a skin of rigid glass
surrounding the molten core.
•As the molten core solidifies
it tends to shrink. The pull of
the solidifying molten core,
as it shrinks, creates residual
compressive stresses within
the outer surface,
46. Limitations;
Simple shapes are required such that
uniform stresses distributions can
occur, Dental restorations, however, are
characterized by complex shapes, sharp
angles and varying thickness.
47. 2. Glazing:
•By coating the core
ceramic with a thin layer
of a veneering ceramic
having a slightly lower
(CTE).
•This mismatch allows the core material to
contract slightly more upon cooling; leaving the
veneering ceramic in residual compression
48. 3) Ion Exchange or chemical tempering:
•This process involves the exchange of larger
K+ ions for the smaller Na + ions (a common
constituent of a variety of glasses).
•By placing the glass in a bath of molten
potassium nitrate, K+ ions in the bath exchange
places with some of Na + of the glass particles.
The K+ is larger than the Na + . crowding of the
K+ ions in place previously occupied by the
smaller Na + ion creates residual compressive
stresses in the surfaces of the glass .
49. Limitation
the depth of the compression
zone is less than 100 μm, so
that this effect would be
easily worn out after long–
term exposure to certain
inorganic acids.
52. •Using strong
core materials with
appropriate
thickness; since
these stresses are
distributed on the
inner surface (core
material is in
tension).
Occlusal force
Compressive
stresses
Tensile stresses
cracking
54. •The marginal designs generally
accepted during ceramic crowns
preparation are;
•deep chamfer
• flat shoulder
• shoulder with rounded internal
angles.
•Acute angled preparations
[beveled or featheredge]finish lines are to be
avoided
55. •Non-uniform finish line causes the
porcelain at the cervical region to vary in
thickness with a potential for premature
fracture during fabrication procedures, in the
process of seating or after cementation.
•All transitions and line angles are to be
rounded to avoid stress concentrations.
56. •Accurate registration of
occlusion, avoiding the
premature
contacts
which may act as stress
bearing zones on the
ceramics.
•Adequate cement gap
(internal relief) to avoid
tensile stresses exerted
from excess luting
cement on ceramic
crown
57. •Adhesive cementation is preferred
because conventional cements are strong in
compression and weak in tension.
In case of a FPD,
The connectors
are the weakest
point and the
most stress
bearing area
58. •To reinforce the connector area:
1. Increasing the
connectors height
to at least 4mm.
However, in the
posterior region
subjected to higher
loads, the
2. The minimal recommended
connector height
connector cross section
may be limited by
area is 12–16 mm2
the short clinical
although this may interfere
molar crowns.
with biological and esthetic
considerations.
59. Continuous change in
dimensions
Sudden change
Increasing the Radius of curvature at the
connectors area in the gingival embrasure to
0.45 mm increases the fracture resistance as it
allows the crack to propagate smoothly from
the gingival embrasure toward the pontic
smoothly .
63. Zirconia (ZrO2) ceramic is a good example for
this mechanism. The material is polymorph
occurring in three forms:
monoclinic (M) at room temperature
tetragonal (T) ≥ 1170C and cubic(C) ≥ 2370°C.
Pure zirconia at room temperature
Pure zirconia at 1170 C
64. Transformation from the monoclinic to the
tetragonal phase is associated with a 5%
volume decrease.
Reversely, during cooling, the transformation
from the tetragonal to the monoclinic phase is
associated with a 3% volume expansion.
65. The inhibition of these transformations
can be achieved by adding stabilizing
oxides (CaO, MgO, Y2O3), which allow
the existence of tetragonal-phase
particles at room temperature.
66. When stress develops in the tetragonal
structure and a crack in the area begins to
propagate,
the tetragonal grains transform to
monoclinic grains.
The associated volume expansion
results in compressive stresses at the
edge of the crack and extra energy is
required for the crack to propagate further.