Anatomy and clinical significance of denture bearing areasOgundiran Temidayo
A presentation on the anatomy and clinical significance of the denture bearing areas by Ogundiran Temidayo who is a dental student at OBAFEMI AWOLOWO UNIVERSITY ILE-IFE
a detailed account of the principles of tooth preparation with main reference from Shillingburg
The presentation is available on request. Mail me at apurvathampi@gmail.com
Anatomy and clinical significance of denture bearing areasOgundiran Temidayo
A presentation on the anatomy and clinical significance of the denture bearing areas by Ogundiran Temidayo who is a dental student at OBAFEMI AWOLOWO UNIVERSITY ILE-IFE
a detailed account of the principles of tooth preparation with main reference from Shillingburg
The presentation is available on request. Mail me at apurvathampi@gmail.com
A simplified explanation of mucostatic and mucocompressive and selective pressure impression technique. difference between rigid and non rigid with the advantages and disadvantages
types of materials, manipulation techniques, uses had described in detail. based on exam point of view
Luting agents for fixed prosthodontics/ orthodontic course by indian dental a...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.
This ppt contains detailed presentation of dental Materials topic, Zinc Oxide Eugenol cements. It will help students to understand different concepts through images. This presentation is Made by Toor E Cina Jadoon, a Student of Sardar Begum Dental college. keep sharing , keep caring. Allah Help those who help others. Jazak allahu khhyr .
Thanks..
ARTIFICIAL INTELLIGENCE IN HEALTHCARE.pdfAnujkumaranit
Artificial intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems. It encompasses tasks such as learning, reasoning, problem-solving, perception, and language understanding. AI technologies are revolutionizing various fields, from healthcare to finance, by enabling machines to perform tasks that typically require human intelligence.
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
Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
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.
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
2 Case Reports of Gastric Ultrasound
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
Tom Selleck Health: A Comprehensive Look at the Iconic Actor’s Wellness Journeygreendigital
Tom Selleck, an enduring figure in Hollywood. has captivated audiences for decades with his rugged charm, iconic moustache. and memorable roles in television and film. From his breakout role as Thomas Magnum in Magnum P.I. to his current portrayal of Frank Reagan in Blue Bloods. Selleck's career has spanned over 50 years. But beyond his professional achievements. fans have often been curious about Tom Selleck Health. especially as he has aged in the public eye.
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Introduction
Many have been interested in Tom Selleck health. not only because of his enduring presence on screen but also because of the challenges. and lifestyle choices he has faced and made over the years. This article delves into the various aspects of Tom Selleck health. exploring his fitness regimen, diet, mental health. and the challenges he has encountered as he ages. We'll look at how he maintains his well-being. the health issues he has faced, and his approach to ageing .
Early Life and Career
Childhood and Athletic Beginnings
Tom Selleck was born on January 29, 1945, in Detroit, Michigan, and grew up in Sherman Oaks, California. From an early age, he was involved in sports, particularly basketball. which played a significant role in his physical development. His athletic pursuits continued into college. where he attended the University of Southern California (USC) on a basketball scholarship. This early involvement in sports laid a strong foundation for his physical health and disciplined lifestyle.
Transition to Acting
Selleck's transition from an athlete to an actor came with its physical demands. His first significant role in "Magnum P.I." required him to perform various stunts and maintain a fit appearance. This role, which he played from 1980 to 1988. necessitated a rigorous fitness routine to meet the show's demands. setting the stage for his long-term commitment to health and wellness.
Fitness Regimen
Workout Routine
Tom Selleck health and fitness regimen has evolved. adapting to his changing roles and age. During his "Magnum, P.I." days. Selleck's workouts were intense and focused on building and maintaining muscle mass. His routine included weightlifting, cardiovascular exercises. and specific training for the stunts he performed on the show.
Selleck adjusted his fitness routine as he aged to suit his body's needs. Today, his workouts focus on maintaining flexibility, strength, and cardiovascular health. He incorporates low-impact exercises such as swimming, walking, and light weightlifting. This balanced approach helps him stay fit without putting undue strain on his joints and muscles.
Importance of Flexibility and Mobility
In recent years, Selleck has emphasized the importance of flexibility and mobility in his fitness regimen. Understanding the natural decline in muscle mass and joint flexibility with age. he includes stretching and yoga in his routine. These practices help prevent injuries, improve posture, and maintain mobilit
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
2.
(n): 1. A powder of calcium oxide, silica,
and alumina used as an ingredient of
mortar and concrete.
2. A binding element. A substance which
makes objects adhere to each other or
something serving to unite firmly.
3.
Dental cements are brittle materials.
They are supplied mainly as powder & liquid.
When mixed to a thin consistency , they are used to
retain - indirect restorations.
- orthodontic bands & brackets
When mixed to a thick consistency , they are used
as:- low strength bases [liner]
- high strength bases
- temporary filling
- root canal sealer
4.
5.
Dental cements can be classified according to the
basic constituent of the powder into:
Zinc oxide based cements
Ion leachable glass based cements
Resin based cements
Others
6.
There are three types :
Zinc Oxide - Eugenol Cement
Zinc Phosphate Cement
Zinc Polycarboxylate Cement
7. Supplied Form: - Powder & Liquid
- Two pastes of contrast colors
- One ready made paste
Composition :
Powder:
- Zinc oxide [sintered to control
its reactivity ]
- Magnesium oxide
- Zinc acetate [accelerator]
Liquid:
- Eugenol [component of oil of
cloves ; weak organic acid]
- Other oil *to mask taste
*to modify viscosity
8.
Setting Reaction :
It is an acid base reaction [ chelation reaction ].
Base + Acid
Salt + H2O
It is a surface reaction
cored structure
P+L
Un-reacted ZnO
moisture +Free Eugenol
+Hydrated Zinc Eugenolate
[amorphous matrix ]
H20 changes ZnO into Zn(OH)2 to react with eugenol
Factors accelerating the setting reaction: * Heat
* Moisture
.·.It sets quickly in the patient`s mouth
The setting reaction is accompanied by slight expansion
9.
Manipulation:
Proportioning according to use .
Optimum P/L should be obtained to achieve best
properties for the cement
or
Equal lengths of the two pastes
Mixing on oil resistant paper pad or glass slab with
stainless steel spatula .
Add all the powder into the liquid at once or
Mix the two pastes until uniform color is obtained
The mix is first putty , then by further mixing a
suitable consistency [thick & crumbly] is obtained
S.T.~10 min. M.T.~1-1.5 min W.T. long
10.
Properties:
1.
Biological Properties:
Its pH is ~7 [neutral]
no chemical irritation
It is sedative in deep cavity [Eugenol]
N.B.
It is highly irritant to the exposed pulp
Anti-bactreial effect [ZnO +Eugenol]
Thermal insulation when used in thick layer
[>0.5mm]
11. Properties:
2. Consistency & Film Thickness:
They depend on
- Powder particle size
- Powder/Liquid [application]
- Viscosity of the mix
12. Properties :
2. Consistency & Film
Thickness :
For luting application , thin
film thickness [free of
defects] is required
[less
than 25µm]
A 2-3 cm string of the mix
occurs , when the flat
surface of the St. St.
spatula is pulled from the
mix
13. ZnO-E has a moderate film thickness 2535µm
For other applications , a thick film
thickness is required
[not less than
40µm]
The mix has the consistency of pie dough
; it can be rolled into a ball with fingers
[nonsticky]
15.
Properties:
4.
Solubility :
It depends on
- Composition
- P/L [ high ratio is desirable]
- Handling of the mix
ZnO-E is the most soluble dental cement due to:
- Leaching of free Eugenol
- Hydrolysis of Zinc Eugenolate matrix
16. Properties :
5. Mechanical Properties :
They depend on - Composition
- P/L [high ratio is desirable]
- Handling of the mix
Poor mechanical properties .
- Compressive strength ~15 MPa
- Tensile strength
~ 5 MPa . ·.brittle
This makes the removal of excess after application &
complete setting
of the cement easier
17.
Modulus of elasticity ~ 5×103 Mpa
Mismatch in the elastic moduli of the base &
restoration create tensile stresses at their
interface causing fracture of either material
.·.The conventional ZnO-E can not be used as a
base under amalgam restoration
18.
19.
Properties :
6.
Retention (Bonding) :
The bond strength of dental cement depends on :
- Strength of the cement
- Film thickness of the cement
- Surface texture of the tooth & restoration
- Design of the restoration
It bonds by mechanical interlocking
20. Properties :
7. Optical Properties :
The presence of un-reacted ZnO in the set mass
Opaque cement
.·.It is contraindicated to be used with translucent
restoration
21.
1.
Modifications:
These are performed either for
powder
liquid
both
Zinc Oxide Noneugenol Cement :
The liquid is formulated with aromatic oils other
than eugenol for patients sensitive to it
22. Modifications :
2. Polymer Reinforced Zinc Oxide –Eugenol
Cement
Powder : - ZnO
80%
- Resin
20 %
Liquid : - Eugenol
- Polysterene
This is for
Solubility
Strength
since the polymer is of low water solubility .
23.
3.
Modifications:
EBA –Alumina Reinforced Cement :
Powder :
- ZnO
70%
- Alumina
30%
Liquid :
- Ethoxybenzoic acid 62%
pinkish in colour
- Eugenol
38%
Alumina in the powder is strong inert additive
The EBA in the liquid allows for the formation of stronger
crystalline matrix
24. Modifications
4.
Slow & Rapid Setting Cement :
The slow setting cement takes 24 hrs to set .
The fast setting cement takes only 5 min. to set .
This depends on * Nature of the powder
* Its particle size
* Concentration of accelerator
25.
Applications :
Low strength base
[liner]
High strength base
[modified version]
Provisional restoration [ filling & cementation]
Final cementation
[ modified version]
Root canal sealer
[ slow setting version]
Periodontal dressing
Surgical dressing
N.B.
Never use ZnO-E with resin based restorations , because
eugenol inhibits their polymerization
strength & aesthetics of C.R.
26.
Introduction :
It is the oldest & most popular cement ,
because of : * Its long history of clinical success
* Favorable handling properties
[i.e. well defined W.T. & rapid S.T.]
* Many applications
Supplied Form :
Powder & Liquid
27.
Composition :
Powder : - Zinc oxide [sintered to control its
reactivity ]
- Magnesium oxide
- Other oxides
* Strength & Smoothness
- Fluorides [only when used for
cementation in orthodontic ]
Liquid : - Aqueous solution of phosphoric acid
Dilution is necessary for the ionization of the
acid to react with the powder
- Aluminum phosphate *Buffer
*Cement former
28.
Setting Reaction :
It is an acid base reaction
Base + Acid
Salt + H2O
It is a surface reaction
cored structure
P + L Mg
Un-reacted ZnO
AL
+Hydrated Zinc-Alumino- Phosphate
[ porous amorphous matrix ]
The reaction is
* exothermic
* accompanied by slight shrinkage
29.
Manipulation :
Proportioning according to use
Optimum P/L should be obtained to achieve best
properties for the cement
Mixing is done on glass slab with ST.ST. spatula
The setting reaction is exothermic causing the
ZnPH mix to set rapidly
S.T.~5-9 min. M.T.~1-1.5 min. W.T. well defined
30.
1.
2.
3.
Manipulation :
For heat dissipation , the following should be
performed :
Use cool dry glass slab , not below the dew point
to avoid moisture condensation [ to keep H2O
content & reaction rate constant ]
Slow addition of small increments of powder to
the liquid
Mixing is done over large area of the glass slab
until the desired consistency is obtained
31.
1.
2.
3.
Manipulation :
N.B.
Any delay after mixing, the viscosity increases rapidly
resulting in larger film thickness
This will impair the proper seating of the restoration during
cementation
Care of the liquid
To keep H2O content & reaction rate constant
Keep the liquid in stoppered bottles
Dispense the liquid just before mixing
Discard the last third [clear or cloudy ]
32. Properties :
1.
Biological Properties :
ZnPH is irritant to the pulp because of
- Its initial acidic pH reaching neutrality within 48 hrs
- No anti bacterial effect
- Slight setting shrinkage
.˙. ZnPH base should be preceded in deep cavity by
- Cavity varnish
- Subbase [cavity liner]
- Dentin bonding agent
Thermal insulation when used in thick layer [>0.5mm]
Fluoride release in certain formulations
33.
1.
1.
2.
Properties :
Biological Properties :
N.B.
The patient may feel some pain during cementation
This can be the result of:
Acidic pH of the cement ; especially for too thin mix
Osmotic pressure developed by the movement of
fluid through the dentinal tubules
This pain is only transient & should subside within few
hrs
35.
Properties :
2.
Consistency & Film Thickness:
They depend on - Powder particle size
- Powder/Liquid [application]
- Viscosity of the mix
36.
37. Properties :
2. Consistency & Film Thickness :
For luting application , a thin film thickness [free of
defects] is required
[less than 25µm]
A 2-3 cm string of the mix occurs , when the flat surface of
the St St spatula is pulled from the mix
ZnPh is known as Crown & Bridge Cement , because
it has the thinnest film thickness
For other applications , a thick film thickness is required
[not less than 40µm]
The mix has the consistency of pie dough ; it can be rolled
into a ball with fingers [nonsticky]
40. Properties :
4. Solubility :
It depends on
- Composition
- P/L [ high ratio is desirable]
- Handling of the mix
ZnPH is soluble in water for the first 24 hrs after
setting ~ 0.04 - 0.2%
Then the solubility is much reduced
The fluoride containing type shows some fluoride
release
decalcification around cemented
orthodontic bands
41. Properties :
Mechanical Properties :
They depend on - Composition
- P/L [high ratio is desirable]
- Handling of the mix
- Compressive strength ~100-150 MPa
- Tensile strength
~ 3-4 MPa . ·. Brittle
This makes the removal of excess after application &
complete setting of the cement easier
- Modulus of elasticity ~ 13×103 MPa [~to dentin]
Mismatch in elastic moduli of the base & restoration create
tensile stresses at their interface causing
fracture of either material
.·.It can be used as a base under amalgam
5.
42. Properties :
6. Retention (Bonding) :
The bond strength of dental cement depends on :
- Strength of the cement
- Film thickness of the cement
- Surface texture of the tooth & restoration
- Design of the restoration
It bonds by mechanical interlocking
43. Properties :
7. Optical Properties :
The presence of un-reacted ZnO in the set mass
Opaque cement
.·.It is contraindicated to be used with translucent
restoration
44.
Applications :
High strength base
Provisional restoration [ filling]
Final cementation of - Metallic restorations
- Ceramometallic restorations
- Orthodontic bands
45.
Supplied Form :
Powder & Liquid
Preproportioned capsule for mechanical mixing
Water settable cement
The liquid is freeze dried & added to the powder
This mixture will be only mixed with distilled H2O
This supplied form has been developed
- To achieve correct P/L , because the viscous
liquid does not make independent drops thus
giving inaccurate amount
- To avoid thickening of the liquid
46.
Composition :
Powder :
-Zinc oxide [ sintered to control its
reactivity ]
- Magnesium oxide
- Other oxides * Strength
Smoothness
- Fluorides [ only when used for
cementation in
orthodontics ]
47.
Composition :
Liquid :
-Aqueous solution of polycarboxylic acid
copolymer
Dilution is necessary for the ionization of
the acid to react with powder
Copolymerization is necessary to avoid
thickening of the liquid
- Sodium Hydroxide *Buffer
- Tartaric acid
*To control S.T. by
controlling the dissolution
of powder surface
48.
Setting Reaction :
It is an acid base reaction
Base + Acid
Salt +H2O
It is a surface reaction
P+L
cored structure
- Un-reacted ZnO
+Hydrated Zinc Polycarboxylate
[amorphous matrix ]
Factors affecting setting reaction * Heat
49.
Manipulation :
Proportioning according to use
Optimum P/L should be obtained to achieve
best properties for the cement
Mixing is done on glass slab with plastic
spatula , because ZnPolyc. adheres to the ST.
ST. spatula
S.T.~7-9 min. [long] M.T.~30-60 sec. W.T.
short
50.
1.
2.
1.
2.
Manipulation :
Extend the W.T. by
Use of cool dry glass slab , not below the dew point to
avoid moisture condensation [to keep both H2O content
& reaction rate constant ]
The powder is added to the liquid in only two halves
N.B.
The correct consistency of the mix is viscous , but the mix
will flow under pressure
The mix should be only used as long as it has glossy
surface , otherwise there will be
* Initial setting of the cement
* No free COOH groups for adhesion
51.
Manipulation :
Care of liquid :
To keep both H2O content & reaction rate
constant
1.
Keep the liquid in stoppered bottles
2.
Dispense the liquid just before mixing
3.
Discard the last third [ clear or cloudy ]
52. Properties :
1. Biological Properties :
Its pH is acidic
chemical irritation
It is less irritant than ZnPh , because the
following :
1. Polycarboxylic acid is weaker than
phosphoric acid
2. Rapid rise to neutrality within 24 hrs
3. Large molecular size of the acid
Difficult
penetration inside the dentinal tubules
53.
Properties :
1.
Biological Properties :
Some antibacterial effect [ZnO]
Thermal insulation when used in thick layer
[>0.5mm]
Fluoride release in certain formulations
54.
Properties :
2.
Consistency & Film Thickness:
They depend on - Powder particle size
- Powder/Liquid [application]
- Viscosity of the mix
55.
2.
Properties :
Consistency & Film Thickness :
For luting application , thin film thickness [free of defects] is
required
[less than 25µm]
A 2-3 cm string of the mix occurs , when the flat surface of the
plastic spatula is pulled from the mix
ZnPolyc. has the highest film thickness 25-48µm
.·.It is difficult to completely seat a retentive well fitting
restoration
For other applications , a thick film thickness is required
[not
less than 40µm]
The mix has the consistency of pie dough ; it can be rolled into
a ball with fingers [nonsticky]
57. Properties:
4. Solubility :
It depends on
- Composition
- P/L [ high ratio is desirable]
- Handling of the mix
ZnPolyc. is ~as soluble as ZnPh
The fluoride containing type shows some fluoride
release decalcification around cemented
orthodontic bands
58. Properties :
5. Mechanical Properties :
They depend on - Composition
- P/L [high ratio is desirable]
- Handling of the mix
- Compressive strength ~55-95 MPa
- Tensile strength
~ 3-6 MPa
.·. Brittle This makes the removal of excess after application &
complete setting of the cement easier
- Modulus of elasticity ~ 4×103 MPa
Mismatch in elastic moduli of the base & restoration
create tensile stresses causing fracture of either material
59.
6.
1.
2.
Properties :
Bonding :
The bond strength of dental cement depends on:
- Strength of the cement
- Film thickness of the cement
- Surface texture of the tooth & restoration
- Design of the restoration
It bonds by chemical bonding of COOH group to
Inorganic portion in enamel & dentin
Bond to enamel> Bond to dentin [ higher inorganic % in
enamel ]
Base metal alloys [ presence of surface oxide ]
60. Properties :
6. Bonding :
N.B.
Chemical bond of ZnPolyc>Chemical bond of
G.I. due to moisture sensitivity of G.I.
ZnPolyc. does not bond chemically to gold
alloy restorations
It bonds by mechanical interlocking
61. Properties :
7. Optical Properties :
The presence of un-reacted ZnO in the set mass
Opaque cement
.·.It is contraindicated to be used with translucent
restoration
64. Cement Base
Used to encourage recovery of the
injured pulp and to protect it against
further chemical or thermal insult
Serves as a substitute for dentin lost
due to decay or preparation
Primary difference between liners and
bases
THICKNESS (>0.75 mm)
69.
Setting Reaction :
It is an acid base reaction [chelation reaction]
Base + Acid
Salt + H2O
It is a surface reaction
cored structure
P+P
- Un-reacted Calcium Hydroxide
+ Calcium Disalicylate
[amorphous matrix]
Factors affecting setting reaction : *Moisture
.·.It sets quickly in the patient`s mouth
70.
Manipulation :
Equal lengths of the two pastes are dispensed
on a paper pad
They are mixed with ST.ST. spatula to uniform
color
The mix is applied only to the cavity floor , as it
is highly soluble
S.T.~2-5min. M.T.~30 sec.
71.
Properties :
1.
Biological Properties :
Its pH is alkaline
un-reacted Ca(OH) 2
.·. It stimulates secondary dentin precipitation ,
when placed in contact to minute traumatic pulp
exposure [direct pulp capping]
Antibacterial effect
Thermal insulation when used in thick layer
72. Properties :
2. Consistency & Film Thickness :
Creamy consistency
Thin film thickness
3.
4.
Dimensional Changes on Setting :
Not mentioned
Solubility :
It is highly soluble
.·.It should not be left on cavity walls or margins
76.
Supplied Form :
- Liquid [clear ;yellowish]
Composition :
- Resin [natural or synthetic]
dissolved in organic solvent
[ alcohol ,acetone or ether ]
77.
Manipulation :
It is applied by a disposable brush [to avoid
contamination] to all cavity walls
The solvent will evaporate leaving a thin coating
of resin
Use a gentle stream of air for drying
Repeat the application up to three times to
ensure a thin uniform coating of resin [more
protective than one thick application]
Tightly cap the cavity varnish bottle immediately
after use to avoid evaporation of solvent
78.
Applications :
It decreases marginal leakage around restorations
It decreases the passage of chemicals from irritating
base, cement or restoration
It protects against the loss of constituents from the
surface of the filling
N.B.
It should not be used under C.R. because it interferes
with the action of the bonding agent which already seal
the dentinal tubules
It should not be used under G.I. because it interferes
with fluoride uptake & chemical bonding