Major challenges in cosmetic dentistry are to accomplish appropriate and satisfactory reproduction of natural shade of teeth.1
The kind of shade guide, individual ability to choose shades and conditions the choice is made under, all have influence on reliability and accuracy of the procedure.
Shade selection in dental practice is an important but difficult task.
Dentists are challenged to satisfy the aesthetic requirement of patients when they select the shades for fabrication of prosthesis. Most dentists are usually not trained for shade selection.2
Tooth Colored Restorative Materials describes in brief regarding the various materials used as cements and crown for loss of tooth structure either by caries or other factors like trauma, GERD, Abrasion etc
Major challenges in cosmetic dentistry are to accomplish appropriate and satisfactory reproduction of natural shade of teeth.1
The kind of shade guide, individual ability to choose shades and conditions the choice is made under, all have influence on reliability and accuracy of the procedure.
Shade selection in dental practice is an important but difficult task.
Dentists are challenged to satisfy the aesthetic requirement of patients when they select the shades for fabrication of prosthesis. Most dentists are usually not trained for shade selection.2
Tooth Colored Restorative Materials describes in brief regarding the various materials used as cements and crown for loss of tooth structure either by caries or other factors like trauma, GERD, Abrasion etc
Introduction
History
Bleaching agent
Classification of Bleaching technique.
Vital bleaching technique
Effect of vital bleaching on tooth structure
Effect of vital bleaching on tetracycline stain
Effect of vital bleaching on Fluorosis stain
Effect of vital bleaching on restorative material
Conclusion
References
Endodontic emergencies include Pre-treatment emergency of which hot tooth is a commonly encountered situation.
This ppt is contains concise pickup notes on Hot tooth.
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
Smear layer is a controversial topic in the field of operative dentistry and endodontics. This presentation includes composition, concepts, structure, advantages, disadvantages, and removal methods of smear layer.
IATROGENIC EFFECTS ON THE DENTAL PULP
1.Local Anesthesia
2.Cavity/Crown Preparation
3.Dental Materials
4.Depth of Preparation
5.Specific Materials
6.Vital Tooth Bleaching
PROTECTING THE PULP FROM THE EFFECT OF MATERIALS
VITAL PULP THERAPIES
Introduction
History
Bleaching agent
Classification of Bleaching technique.
Vital bleaching technique
Effect of vital bleaching on tooth structure
Effect of vital bleaching on tetracycline stain
Effect of vital bleaching on Fluorosis stain
Effect of vital bleaching on restorative material
Conclusion
References
Endodontic emergencies include Pre-treatment emergency of which hot tooth is a commonly encountered situation.
This ppt is contains concise pickup notes on Hot tooth.
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
Smear layer is a controversial topic in the field of operative dentistry and endodontics. This presentation includes composition, concepts, structure, advantages, disadvantages, and removal methods of smear layer.
IATROGENIC EFFECTS ON THE DENTAL PULP
1.Local Anesthesia
2.Cavity/Crown Preparation
3.Dental Materials
4.Depth of Preparation
5.Specific Materials
6.Vital Tooth Bleaching
PROTECTING THE PULP FROM THE EFFECT OF MATERIALS
VITAL PULP THERAPIES
it's taken from Ingel's Endodontic.Clinical evidence which indicates the presence of severe pulpal pathosis dictates a treatment policy of pulp extirpation and endodontic therapy
Bacteria are responsible for most pulpal disease The
pulpal injury beneath restorations is also microbial
and not due to cytotoxicity of the materials. Bacteria
and their products occur between the restoration and
the dentin as a result of microleakage Dental caries begins beneath a biofilm of dental plaque
when environmental factors favor the growth and
metabolism of acidogenic bacteria. The population of
bacteria that are present in carious lesions is mixed and
variable.variety of products are released or formed on the
death of the bacteria. These include acids and proteinases
that dissolve and digest the enamel and dentin,
and toxins including lipopolysaccharide (LPS) and
lipotechoic acid (LTA). Although bacteria can readily
travel within dentinal tubules
Tooth resorption is the progressive loss of dentine and cementum by the action of osteoclasts. This is a physiological process in the exfoliation of the primary dentition, caused by osteoclast differentiation due to pressure exerted by the erupting permanent tooth
Pediatric Endodontics - Indirect and Direct pulp capping,Pulpotomy, Pulpecto...Karishma Sirimulla
this seminar consists of basis differences in root canal pattern between primary and permanet teeth followed by various definitions techniques and medicaments used in indirect pulp capping, direct pulp capping, pulpotomy, pulpectomy, apexogenesis and apexification
Tooth hypersensitivity is a common problem encountered in everyday life and clinical practice. This presentation clearly shows causes, methods of prevention and treatment in such cases.
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.
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
MANAGEMENT OF ATRIOVENTRICULAR CONDUCTION BLOCK.pdfJim Jacob Roy
Cardiac conduction defects can occur due to various causes.
Atrioventricular conduction blocks ( AV blocks ) are classified into 3 types.
This document describes the acute management of AV block.
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.
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.
Factory Supply Best Quality Pmk Oil CAS 28578–16–7 PMK Powder in Stockrebeccabio
Factory Supply Best Quality Pmk Oil CAS 28578–16–7 PMK Powder in Stock
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Hot Selling Organic intermediates
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.
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
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
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.
Maxilla, Mandible & Hyoid Bone & Clinical Correlations by Dr. RIG.pptx
pulp protection.pdf
1. Dr. Hadil Abdallah Altilbani
BDS Santiago de Compostela University Spain.
MSc. University of Valencia Spain.
Department of Endodontics University of Palestine .
2.
3.
4. Introduction
Embryologically and physiologically Dentin
and pulp are so intimately related that
dentin can be considered as the peripheral
calcified portion of the dental pulp.
However This intimate relation extends
beyond embryological and physiologic
considerations.
It has important clinical implications.
It means that pulp would react
when dentin is injured whether the
injury is caused by caries, attrition,
abrasion, erosion or operative procedures.
5.
6.
7. Dynamic Dental Pulp
Responds to external stimuli in a variety of ways
A variety of stimuli have been demonstrated to have an effect on the
pulp. The reactions of the dental pulp to respective irritants are largely
dictated by the character and duration of a stimulus.
Ability to form dentin throughout life
Potential for regeneration and repair diminishes with age
Very sensitive to thermal stimuli
Encased in a low compliance environment
Scarcity of collateral circulation
Why pulp is unique?
8. MODES OF IRRITATION TO PULP
• 1. DIRECT-
• Direct irritation to the pulp-
Dentin organ- Carious/
iatrogenic pulp exposure
• Allows direct access for the oral
flora and other irritating
ingredients
• 2. INDIRECT-
• Irritating toxins/chemicals enter
through the dentinal tubules
9. 1. Bacterial irritants:
Most common cause for pulpal
irritation are bacteria or their
products which may enter pulp
through a break in dentin either
from:
– Caries
– Accidental exposure
– Fracture
– Percolation around a restoration
– Extension of infection from
gingival sulcus
– Periodontal pocket and abscess
– Anachoresis (Process by which
microorganisms get carried by the
bloodstream from another source
localize on inflamed tissue).
PULPAL IRRITANTS
10. 2. Iatrogenic:
– Thermal changes.
– Orthodontic movement
– Periodontal curettage
– Periapical curettage
– Use of chemicals like temporary and permanent
fillings.
3. Idiopathic
– Aging
– Resorption—internal or external.
4. Traumatic
Acute trauma like fracture
Chronic trauma including parafunctional
12. Dental caries - Facts
• Dental caries is the most common route for
causing irritation to the pulp.
• Dental caries is localized, progressive, decay of the teeth
characterized by demineralization of the tooth surface
by organic acids, produced by microorganisms .
• From the carious lesion, acids and other toxic substances
penetrate through the dentinal tubules to reach the
pulp.
• Destroys dentin at a rate of 1mm/six months
13. Pulpal Reaction to caries
Three basic reactions protecting pulp
1. Decrease in dentin permeability
2. Tertiary dentin formation
3. Inflammatory & Immune reactions
14. Dentin permeability -
Importance
• Channels of diffusion – Dentinal tubules
• More no of tubules per unit area
towards pulpal side as compared to
peripheral dentin
• Clinical importance – Dentin
beneath a deep cavity
preparation is more permeable
than dentin underlying a shallow
cavity
15. Decrease in dentin permeability
• First defense to caries
– SCLEROTIC DENTIN
Combination of
• An increased deposition of intratubular dentin
• Direct deposition of mineral crystals (Whitlokite) into narrowed
dentinal tubules
18. 3. Pulpal Immune Response
• The bacterial toxins, enzymes, organic acids and the products of tissue
destruction show inflammatory response in the pulp.
• The degree of pulpal inflammation beneath a carious lesion depends on
closeness of carious lesions with pulp and permeability of underlying
dentin.
• Early response is characterised by focal accumulation of
chronic inflammatory cells
• Dental caries stimulates the accumulation of pulpal dendritic cells in
and around odontoblastic layer
Progressive inflammation
21. EFFECT ON PULP
•Intact pulpal blood flow is critical
•Dental pulp is enclosed in a rigid chamber and
cannot benefit from collateral circulation
•Reduction of blood flow – Reduction in clearance
of large molecular weight toxins or waste
products •
•Reduction in blood flow during a restorative
procedure could lead to an increase in
concentration of irritants accumulating within
the pulp.
•Vasoconstrictor of local anesthetic (LA)
potentiates and prolongs anesthetic effect by
reducing blood flow in the area.
22. • Local Anaesthetic delivered through an intra osseous
route or periodontal ligament route The supplemental
anesthetic techniques can compromise the inflamed pulp’s
ability to heal by reducing the blood flow
•Fortunately, the rate of oxygen consumption in the
healthy pulp is relatively low, and if necessary, pulp cells
can produce energy anaerobically through the pentose
phosphate pathway of carbohydrate metabolism.
26. One key requirement of a successful restorative
procedure maintaining the pulp vitality is to cause
minimal additional irritation of the pulp so as not to
interfere with normal pulpal healing.
• This involves the avoidance of thermal stimuli
caused by operative procedures, toxicity of
restorative materials and bacteria penetration.
27. Factors affecting response of pulp to tooth preparation
1. • Pressure
2. • Heat
3. • Vibration
4. • Remaining dentin thickness
5. • Thermal and mechanical injury
6. • Speed
7. • Nature of cutting instruments.Heat
3-PULPAL REACTION TO RESTORATIVE
PROCEDURE
28. 1. The Pressure of instrumentation
On exposed dentin causes the aspiration of the
nuclei of the odontoblasts or the entire
odontoblasts themselves or nerve endings from pulp
tissues into the dentinal tubules.
This will stimulate odontoblasts, disturb their
metabolism and may lead to their complete
degeneration and disintegration.
This can occur by excessive pressure of hand or
rotary instruments, especially in decreased effective
depths.
Sometimes this pressure may move some
microorganisms from infected cavity floor or wall
into the pulp, leading to its irritation.
Factors affecting response of pulp to tooth preparation
32. Cutting of dentin with always produces some amount of
heat which is determined by several factors such as:
Mech.Energy >>>> Cut + Heat
Based on that equation several factors influence the
quantity of the heat produced;
i. Size and shape of the cutting instrument.
ii. Speed of rotation.
iii. Length of time, the instrument is in contact with dentin.
iv. Amount of pressure exerted.
Factors affecting response of pulp to tooth preparation
• Heat
33. 2. Heat production
Is the second most
damaging factor.
Any restorative procedures leads
to increase in pulpal temperatures
Irreversible pulp pathosis → pulp
abscess formation
If the cavity floor ≤ 0.5 mm from
the pulp, areas of coagulation
necrosis could be detected.
34. That “heat” is a function of:
a. RPM (apeed), i.e. more the RPM more is the heat production.
b. Pressure is directly proportional to heat generation.
c. Surface area of contact, which is related to the size and shape of the
revolving tool.
The more the contact between the tooth structures and revolving tool, the more is the
heat generation.
Heat creates destruction in the pulp tissues, coagulate protoplasm, and burn dentin if
the temperature is amply elevated.
d. Desiccation, if occurring in vital dentin such that water in the protoplasm of
Tome’s fibers is eliminated, can cause aspiration of the odontoblasts into the tubules .
The subsequent disturbances in their metabolism may lead to the complete
degeneration of odontoblasts.
Desiccation increases the permeability of the vital dentin to irritants like
microorganisms or restorative materials.
35.
36. Blushing of teeth during or after cavity or crown
preparation has been seen in teeth after cutting.
After dentin is cut, the coronal dentin develops pinkish hue and this hue
is due to vascular stasis and hemorrhage in the sub-odontoblastic layer.
37.
38. • First principle to
eliminate sources of
pulp injury is
NEVER
CUT DRY
Coolant sprays should be used even in
nonvital or devitalized tooth structures,
since the heat will burn the tooth
structures, and these burnt areas will be
sequestrated later leaving a space
around the restoration where failures
can occur.
39. Use of Coolants
In deep cavities air blast should
not be used to dry the cavity,
instead cotton pellets should be
used. Or use short blasts of air.
Air blast can cause desiccation of
dentin which can damage the
odontoblasts.
Water spray is considered as the
ideal coolant.
Coolants are most effective method
to reduce the thermal damage.
40. 3. Vibrations
The higher the amplitude, the more destructive may be the response of the
pulp.
The reaction is termed as the rebound response which is due to
the effect of the ultrasonic energy induced.
It is characterized by:
1. Disruption of the odontoblasts
2. Edema
3. Fibrosis of pulp tissues proper.
4. Changes in ground substance.
In addition to affecting the pulp tissues, vibration can create
microcracks in enamel and dentin.
These cracks may transmit and coalesce, directly joining the oral
environment with pulp and periodontal tissues.
Vibrations also increase the permeability of the dentin and enamel.
41.
42. Vibratory phenomenon.
Shock waves produced by vibration are
particularly pronounced when:
The cutting speed is reduced.
Distorted bur.
Loose bur clutch.
Eccentric rotation looseness of handpiece tip.
43. Physical irritation from a procedure
Factors affecting response of pulp to tooth preparation
1) • Pressure
2) • Heat
3) • Vibration
4) • Remaining dentin thickness
5) • Mechanical injury
6) • Speed
7) • Nature of cutting instruments.Heat
44. The depth of the cavity
is the most disadvantageous
exasperating factor to the pulp.
Most important is the thickness of
the dentin bridge between the
floor of the cavity and the roof of
the pulp chamber, also termed as
the effective depth.
Lesser is the effective depth,
more destructive the pulpal
response will be.
DENTIN THICKNESS
. REMAINING
4
45. • Most critical factor in determining the intensity of pulp reaction is RDT
• 2mm of RDT provides adequate protection
• So it is advocated that if RDT < 2mm
• USE OF A PROTECTIVE BASE IS MANDATORY
46. Importance of remaining dentin thickness
0.5mm
1 mm
2 mm
Remaining
dentin
thickness
25%
10%
Minimal
or nil
Effect of
toxic
substances
47. Physical irritation from a procedure
Factors affecting response of pulp to tooth preparation
1) • Pressure
2) • Heat
3) • Vibration
4) • Remaining dentin thickness
5) • Mechanical injury
6) • Speed
7) • Nature of cutting instruments.Heat
48. 6. Speed
Speed of Rotation
Ultra high speed should be used for removal of enamel and
superficial dentin.
It should be kept in mind that without the use of
coolant there is no safe speed.
High speed without coolant can produce burning of dentin,
which in turn affects the integrity of the pulp.
49. 7. Nature of Cutting Instrument
Thermal damage to the pulp was greater with steel burs than
with carbide burs, because of greater heat produced by steel
burs.
Uncooled carbide burs and diamond instruments produce
severe damage to the dental pulp.
Diamond burs cause most damage to pulp due to its abrasive
action and need for increased pressure.
Larger size burs cause greater damage due to increased heat
generation, cutting of larger area and reduced effectiveness of
the coolants.
Improper use of handpiece, use of old, broken down and
damaged handpiece can cause pulpal damage from eccentric
bur rotation and heavy cutting force necessitated by poor
torque characteristic.
50. Effect of Rotary instruments
• Rotary abrasive instruments (stones)
are not recommended for cutting in
vital dentin, as their abrasive action
will elevate the temperature of
surrounding dentin.
• It may crush vital dentin
• It should be confined to enamel
• Rotary cutting instruments (burs) are
biologically acceptable if used over
RDT of 2mm or more
• Carbides provides more cool cutting
51. 1. Tooth Preparation (Restorations/ Crown)
2. Acid Etching
3. Chemicals from restorative materials (Cements/ Bases)
Effects of Caries, Microleakage, Restorative procedures
and materials is Cumulative
Restorative procedures causing pulp injury
52. Acid Etchants
• Acid etching is an important step
in the placement of composite
restorations.
• Commonly used acid etchant is 37
percent phosphoric acid.
• It has been shown that acid etching
does not cause pulpal injury if used
with the recommended time.
• Etching results in the Dissolution
the smear layer opens the dentinal
• tubules and increasing the
permeability of dentin
• On the contrary acid etching also
enhances bacterial penetration of
dentinal tubules
53. 1. Tooth Preparation (Restorations/ Crown) Mechanical and Thermal effect.
2. Acid Etching
3. Chemicals from restorative materials (Cements/ Bases)
Effects of Caries, Microleakage, Restorative procedures
and materials is Cumulative
restorative procedures causing pulp injury
54. EFFECT OF CHEMICAL IRRITANTS ON PULP
Various filling materials produce some irritation ranging from
mild to severe, as do various medicaments used for
desensitization or dehydration of the dentin.
Restorative Materials on Pulp
1. Acidity
2. Absorption of water from dentin during setting
3. Heat generated during setting
4. Poor marginal adaptation leads to bacterial penetration
5. Cytotoxicity of material
55. Cavity Varnishes, Liners, and
Bases
The use of cavity liner is advocated
under restorative material to reduce the
sensitivity of freshly cut dentin and to
protect pulp.
All liners and bases reduce dentin
permeability but to different extents.
Bases provide the largest reduction,
varnishes the least.
60. Zinc Oxide Eugenol
Zinc oxide eugenol is temporary filling material that is also used
for provisional and permanent cementation of crowns, bridges, inlays
and as liner and base.
Of all the filling materials, it has always been considered the safest from
biological aspect.
• Anesthetic properties:
Zincoxide eugenol has been used as an anodyne for pulpal pain.
The sedative effects are apparently because of ability of eugenol to block
or reduce nerve impulse activity.
This effect is obtained only when a reasonably thin mix of ZOE is used
Eugenol, is toxic when placed in direct contact with tissue. .
Another advantage of ZOE is that there is no heat rise during setting.
• Antiseptic properties:
It inhibits bacterial growth on cavity walls.
• Sealing ability:
It has good adaptation to dentin.
61.
62.
63. Zinc Phosphate
Zinc phosphate cement can cause severe pulpal damage because of
its irritating properties.
Toxicity is more pronounced when the cement is placed in deep
cavity preparations.
In deep cavities, zinc phosphate cement should not be used
without an intervening liner of zinc oxide eugenol or calcium
hydroxide.
Effect of zinc phosphate on pulp are due to:
1. • Components of zinc phosphate
2. • Acidic nature
3. • Heat produced during setting
4. • Marginal leakage.
64. Zinc Polycarboxylate Cements
Zinc polycarboxylate cement contains modified zinc oxide powder
and an aqueous solution of polyacrylic acid.
It chemically bonds to enamel and dentin and has antibacterial
properties.
Polycarboxylate cement is well tolerated by the pulp, being
roughly equivalent to zinc oxide eugenol cements in this respect.
Used as cavity liner or luting cement.
68. Amalgam
Amalgam has been used in dentistry since ages.
It is considered one of the safest filling materials
with least irritating properties.
Even if varnish is not employed, within a period of a
few weeks, marginal seal develops between the
tooth and the restoration due to its corrosion
products.
It has been shown to produce discomfort due to its
high thermal conductivity.
So liners or bases are necessary to provide thermal
insulation.
69. Effects of Amalgam on Pulp
• Mild to moderate inflammation in deep caries
• Harmful effects due to corrosion products
• Inhibition of reparative dentin formation due to damage
to odontoblasts
• Copper in high copper alloy is toxic
• High mercury content exerts cytotoxic effects on pulp
• Postoperative thermal sensitivity due to high thermal
conductivity.
70. RESTORATIVE RESINS
Despite having several advantages, they are not considered best
materials because of their high coefficient of thermal expansion
and polymerization shrinkage, which results in marginal
leakage, subsequently the recurrent caries and ultimately the
pulp damage.
Monomer present in composite resins also acts as an irritant to
the pulp.
71. Prevention of Pulpal Damage due to Operative Procedure
• To preserve the integrity of the pulp, the dentist should observe
certain precautions while rendering treatment.
• Excessive force should not be applied during insertion of
restoration.
• Restorative materials should be selected carefully, considering
the physical and biological properties of the material.
• Excessive heat production should be avoided while polishing
procedures.
• Avoid applying irritating chemicals to freshly cut dentin.
• Use varnish or base before insertion of restoration.
• Patient should be called on recall basis for periodic evaluation
of status of the pulp.
72. Science is a mystery that we won’t ever stop trying to reveal its
secrets so what’s the next material we’ll discover?