The document discusses the principles and techniques for cast metal inlay restorations, including materials used, indications and contraindications, advantages and disadvantages. It covers cavity design considerations like apico-occlusal taper, convergence angles, and preparation features. Furthermore, it examines bevel designs and their significance in strengthening tooth structure and improving marginal adaptation of cast restorations.
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
The cast metal restoration is versatile and is especially applicable to Class II onlay preparations. The process has many steps, involves many dental materials, and requires meticulous attention to prepration.
Tooth treatment planned to be restored with an intracoronal restoration, but the decay or fracture is so extensive that a direct restoration, such as amalgam or composite, would not be able to sustain or bear forces.
Additionally, when decay or fracture incorporate areas of cusp or remaining tooth structure that undermines perimeter walls of a tooth, an onlay might be indicated.
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
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
The cast metal restoration is versatile and is especially applicable to Class II onlay preparations. The process has many steps, involves many dental materials, and requires meticulous attention to prepration.
Tooth treatment planned to be restored with an intracoronal restoration, but the decay or fracture is so extensive that a direct restoration, such as amalgam or composite, would not be able to sustain or bear forces.
Additionally, when decay or fracture incorporate areas of cusp or remaining tooth structure that undermines perimeter walls of a tooth, an onlay might be indicated.
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.
A concise and brief presentation on cleaning and shaping of root canals. Colorful and well pictured. Ideal for UG students and PG students to get a good understanding of BMP techniques.
Inlays and onlays / implant dentistry course/ implant dentistry courseIndian 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.
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.
A concise and brief presentation on cleaning and shaping of root canals. Colorful and well pictured. Ideal for UG students and PG students to get a good understanding of BMP techniques.
Inlays and onlays / implant dentistry course/ implant dentistry courseIndian 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.
direct filling gold... material aspect, types, condensation, cavity design, modifications. detaied seminar for post gradutes.... any doubts or suggestions contact dr.mb@hotmail.com
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.
1.Introduction
2.Historical perspective
3.Classification
4.Desirable properties
5.Functional mechanical properties
6.Alloys for
A]. All Metal Prosthesis
B]. Resin – Veneered Metal Restoration
7. High noble and noble alloys for Metal- Ceramic Prosthesis
8. Alternative Technologies for fabricating prosthesis
Biological Hazards and precautions – risks of dental laboratory
technician
10. Guidelines for selection and use of base metals for crown and
bridge applications.
11. Partial denture alloys and guidelines for selection
12. Alternatives technologies for fabricating prosthesis
13. Recent advancements
Materials used in restorations/ orthodontic course by indian dental academyIndian dental academy
Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.
PRESENTATION ON GOLD ALLOYS USED IN DENTISTRY. USEFUL FORALLBRANCHES OF DENTISTRY SPECIALLY PROSTHODONTICS AND CONSERVATIVE DENTISTRY. INCLUDES VARIOUS CATEGORIES OF ALLOYS AND THEIR ADVANTAGES, DISADVANTAGES, USES ETC.
Base-Metal-Alloys used in dentistry..pptxKalpanaNunia1
Dentists should be aware of the corrosion properties and biocompatibility of any alloy they use.
In the absence of detailed data on corrosion for an alloy, use of high-noble and noble alloys of single-phase microstructure will minimize biologic risk.
Patients with Ni allergy may have sensitivity for cobalt. Such patients should be tested to rule out allergy before giving Co-Cr restoration.
Flu Vaccine Alert in Bangalore Karnatakaaddon Scans
As flu season approaches, health officials in Bangalore, Karnataka, are urging residents to get their flu vaccinations. The seasonal flu, while common, can lead to severe health complications, particularly for vulnerable populations such as young children, the elderly, and those with underlying health conditions.
Dr. Vidisha Kumari, a leading epidemiologist in Bangalore, emphasizes the importance of getting vaccinated. "The flu vaccine is our best defense against the influenza virus. It not only protects individuals but also helps prevent the spread of the virus in our communities," he says.
This year, the flu season is expected to coincide with a potential increase in other respiratory illnesses. The Karnataka Health Department has launched an awareness campaign highlighting the significance of flu vaccinations. They have set up multiple vaccination centers across Bangalore, making it convenient for residents to receive their shots.
To encourage widespread vaccination, the government is also collaborating with local schools, workplaces, and community centers to facilitate vaccination drives. Special attention is being given to ensuring that the vaccine is accessible to all, including marginalized communities who may have limited access to healthcare.
Residents are reminded that the flu vaccine is safe and effective. Common side effects are mild and may include soreness at the injection site, mild fever, or muscle aches. These side effects are generally short-lived and far less severe than the flu itself.
Healthcare providers are also stressing the importance of continuing COVID-19 precautions. Wearing masks, practicing good hand hygiene, and maintaining social distancing are still crucial, especially in crowded places.
Protect yourself and your loved ones by getting vaccinated. Together, we can help keep Bangalore healthy and safe this flu season. For more information on vaccination centers and schedules, residents can visit the Karnataka Health Department’s official website or follow their social media pages.
Stay informed, stay safe, and get your flu shot today!
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
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
It surrounds the urethra just below the urinary bladder. It has anterior, median, posterior and two lateral lobes
It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
- 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
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.
Pulmonary Thromboembolism - etilogy, types, medical- Surgical and nursing man...VarunMahajani
Disruption of blood supply to lung alveoli due to blockage of one or more pulmonary blood vessels is called as Pulmonary thromboembolism. In this presentation we will discuss its causes, types and its management in depth.
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
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.
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.
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
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
1. By:-
Abhijeet Khade
P G Student
Dept. of Conservative Dentistry
NHDC
2. CONTENTS:-
Introduction.
Materials for cast restorations
Indications & Contraindications
Advantages and disadvantages
Principles of Cavity design for Cast inlay
restorations.
Tooth preparation for Inlay Class II cast
metal inlays
Bevels- Various types and significance.
Variations in proximal margin design.
Tooth Preparations For Cast Restorations
With Surface Extension.
Conclusion
References
3. INTRODUCTION
Dr. Phil brook in 1897,was the first to introduce
Inlay in dentistry who gave the concept of forming
an investment around a wax pattern, eliminating the
wax, and filling the resultant mold with a gold alloy.
In 1907 Taggart changed the practice of restorative
dentistry by introducing his technique for cast gold
dental restorations.
It was most certainly Taggart who recognized the
significance of cast gold restorations.
4. METERIALS FOR CAST RESTORATIONS
Until recently gold-based alloys have been the only
ones used for cast dental restorations. The ADA
sp#5 still requires 75% of gold-plus- platinum group
metals to be present in alloys for cast restorations
According to Sturdevant there are 4 distinct groups of
alloys.
The traditional high gold alloys.
Low gold alloys.
Palladium-silver alloys
Base metal alloys.
5. ACCORDING TO MARZOUK:
1. Class-I: Gold and platinum group based alloys.
2. Class-II: Low gold alloys (gold content < 50%).
3. Class-III: Non-gold palladium based alloys.
4. Class-IV: Nickel-chromium based alloys.
5. Castable moldable ceramics
6. CHARACTERISTICS OF CAST GOLD
ALLOYS
According to ADA sp#5 the alloys are characterized
as follows-
Type I-soft gold alloys
Type II-medium hard alloys
Type III-hard alloys
Type IV-extra hard alloys
7. According to ADA specification No.5:
1. Type-I (Soft): For restorations subject to very
slight stress such as inlays.
2. Type-II (Medium): For restorations subject to
moderate stress such as onlays.
3. Type-III (Hard): For high-stress situations,
including onlays, crowns, thick veneer crowns
and short-span fixed partial dentures.
4. Type-IV (Extra hard): For extremely high stress
states, such as endodontic posts and cores, thin
veneer crowns, long span fixed partial dentures
and removable partial dentures.
8. Alloy Type Total noble metal content
High Noble (HN) Contains 40 wt.% Au +
60 wt.% of noble metal
elements (Au + Ir + Os + Pd
+ Rh + Ru).
Noble metal (N) Contains 25 wt.% of the
noble metal elements.
Predominantly base metal Contains < 25 wt.% of the
(PB) noble metal elements.
9. In,Fe,Zn,
Type Au Cu Ag Pd
Ga
I 83% 6 10 0.5 Balance
II 77% 7 14 1 Balance
III 75% 9 11 3.5 Balance
IV 69% 10 12.5 3.5 Balance
10. INGREDIENTS OF NOBLE METAL ALLOYS:
The most important element in dental gold alloys is
gold, copper, silver, platinum metals and zinc.
1. Gold:
Gold is primarily responsible for deformability
(ductility).
Ranks lowest in strength.
Characteristic yellow color with a strong metallic
luster.
Density (Sp gravity) 19.3 g/cm3.
Tarnish resistance.
Fusion temperature – 1063o C.
11. 2. Platinum: May be added to
1. Strengthen the alloy.
2. Raise the fusion point (1755).
3. Import rigidity, nobility and hardness.
4. Whiten the alloy.
5. Specific gravity-- 21.37.
6. Also malleable and ductile.
3. Palladium:
Serves the same functions but is much less
expensive than platinum.
12. 4. Iridium, Ruthenium and Rhodium:
Trace amounts of these metals are added as
“Grain Refiners” melting point .
As little as 0.005% is sufficient to refine the grain
size. Grain refiners produce smaller grains.
Fine-grained alloys are generally stronger and
more ductile than coarse-grained alloys.
Indium can also act as a scavenger for the alloy
during casting procedure. Also serve to increase
the tarnish and corrosion resistance.
13. 5. Silver:
It contributes to the strength and hardness of the
alloy. Although it mimics gold in its deformability
effect, it adversely affects the malleability and it
lowers tarnish resistance.
Food containing sulfur compounds, cause severe
tarnish on silver.
Silver serves to balance the red color given by
copper.
Adding small amounts of palladium to silver
containing alloys prevents the rapid corrosion of
such alloys in the oral environment
14. 6. Copper:
Contributes strength and hardness, but
decreases the malleability of the alloy, i.e., it
decreases the tarnish and corrosion resistance .
The content should not exceed 16%. Gives the
alloy reddish appearance. Lowers the fusion
temperature.
7. Zinc: (Present only in low percentages, around
0.5%)
Acts as a deoxidizer and reduces the oxygen
content (because O2 released during
solidification results in porosity).
15. Modu
Dens Yield -lus Rate
Type of Melting Hardne
-ity stren of of
cast Elongation range ss
(gm/ gth elasti tarni
materials (o F) (VHN)
cm3) (MPa) city( sh
PSI)
Class I 20-25% 943-960 16.6 103 80 10-12 0%
Class II 20% 924-960 15.9 186 101 12 2-3%
Class III 15-18% 924-960 15.5 207 121
5-
15
10%
ClassIV 3-11% 834-916 12.8 241 138 30 0%
1021-
ClassV 0% 10.6 262 143 60 0%
1099
16. INDICATIONS
Large restorations
Endodontically treated teeth
Teeth at risk for fracture
Dental rehabilitation with cast metal alloys
Diastema closure and occlusal plane correction
Prosthodontic abutment
Correction of occlusion
Wide open contacts and occlusal plane correction
Adjunct to periodontal therapy to correct tooth
anamolies predisposing to plaque accumulation
Sub gingival lesions
17. CONTRAINDICATIONS
Physiologically young dentition with large pulp
chambers are poor candidates for cast restoration
Developing and deciduous teeth
High plaque / caries indices.
Dissimilar metals.
Esthetics
Small restorations
19. DISADVANTAGES
Extensive tooth preparation
Cemented restoration, discrepancy and micro
leakage
Abrasive and splitting force on natural teeth
Galvanic currents
Number of appointments and higher chair time
Cost and Temporary restoration requirement
Technique sensitive
20. PRINCIPLES OF CAVITY DESIGN FOR CAST
INLAY RESTORATIONS.
Basic differences between Amalgam and Cast
restoration preparation are
Intercuspal distance
Undercuts
Bevels- occlusal and gingival
21. APICO-OCCLUSAL TAPER
PREPARATION
For maximum retention in a cast restoration
opposing walls and opposing axial surfaces of a
tooth preparation should be perfectly parallel to
each other.
Taper should be an average of 2-5 degree from
path of preparation. It can be decreased or
increased according to the length of the preparation
wall and/or axial surface, surface involvement and
internal anatomy in the preparations.
22. CONVERGENT ANGLE
Extension of opposing walls, which diverge toward
the occlusal form a convergent angle. A bisection of
this angle positions the “line of draw” which is
perpendicular to the pulpal floor.
23.
24. PREPARATION PATH:
The preparation should have a single insertion
(draw) path, opposite to the direction of the occlusal
loading. This path is usually parallel to the long axis
of the tooth. So that the completed cavity will have
draft (no under cut).
25. PREPARATION FEATURES OF THE
CIRCUMFERENTIAL TIE
The peripheral margin anatomy of the preparation
is called circumferential tie.
Enamel must be supported by sound dentin.
Enamel rods forming the cavosurface margin
should be continuous with sound dentin.
Enamel rods forming the cavosurface margin
should be covered with the restorative material
Angular cavosurface angles should be trimmed
26. BEVELS
Bevels are the flexible extensions of a cavity
preparation, allowing the inclusion of surface
defects, supplementary grooves, or other areas on
the tooth surface.
Require minimum tooth involvement
Bevels create obtuse-angled tooth structure i.e. the
strongest configuration and acute-angled marginal
alloy i.e. burnish able. Thus makes it possible to
decrease the cement line.
A lap, sliding fit is produced at gingival margin.
It results in 30-degree metal that is burnish able.
Weak enamel is removed.
27. SIX TYPES OF BEVELS
Partial Bevel: involves part of enamel wall, not
exceeding 2/3rds its dimension. It is not used in
cast restorations, except to trim weak enamel rods.
Short Bevel: includes entire enamel wall, but not
dentin, it is used with class-I alloys specially for
type 1 & 2 (Gold platinum based alloys).
Long Bevel: includes all enamel & up to ½ of the
dentinal wall, its major advantage is that it
preserves the internal boxed-up resistance. , most
frequently used for the 1st 3 classes of cast
material.
28. Full Bevel: Includes all of the dentinal and enamel walls
of the cavity wall or floor. Its use should be avoided
except in cases where it is impossible to use any other
form of bevel
Counter Bevel: when capping cusps to protect and
support these, this type of bevel is used, opposite to an
axial cavity wall, on the facial or lingual surface of the
tooth.
Hollow ground bevel (concave)- All the types of bevels
are in the form of a flat plane, but any of them especially
that last three can be prepared in a concave form.
29.
30. PRINCIPLES OF CAVITY DESIGN FOR
CAST INLAY RESTORATIONS
An Inlay is defined as a restoration which has been
constructed out of the mouth from gold, porcelain or
other metal and then cemented into the prepared
cavity of the tooth.
The class-II inlay involves the occlusal and
proximal surfaces of a posterior tooth and may cap
one or more cusps but not all of the cusps.
The class-II onlay involves the proximal surfaces of
a posterior tooth and caps all of the cusps.
31. TOOTH PREPARATIONS FOR CLASS II
CAST METAL INLAYS
Initial preparation
Occlusal step
Proximal box
Resistance and Retention form
Final preparation
Removal of infected caries and pulpal protection.
Preparation of bevels and flares
Modifications
33. OCCLUSAL STEP
Initial entry is made in the central fossa/pit with a
tapered fissure bur no.271 to establish the pulpal
floor (punch cut) to a depth of 1.5mm.
The depth is determined by the extent of existing
carious lesions or restorations or the need for
additional retention
35. Long axis of the bur should be parallel with long axis of
tooth.
36. The occlusal outline is
extended mesiodistally along
the central groove and
stopped just short of the
marginal ridge. The bur is
kept in the vertical position in
the long axis of the tooth
through-out the preparation
so that its taper provides the
3 to 5-degree divergence to
the facial and lingual walls
(total divergence of 6 to 10
degrees).
37. PRIMARY RESISTANCE FORM
Use of box shape
Preservation of cusps and marginal
ridges
Slight rounding of internal line angles
Capping weakened cusps
Adequate thickness of restorative
material
52. M
Insertion of suitable base and completed base.
53. PREPARATION OF BEVELS AND FLARES
The slender flame shaped fine-grit diamond is used
to bevel the occlusal and gingival margins and to
apply the secondary flare on the proximal-facial and
lingual walls.
It will result in 30-400 marginal metal & 140-1500
cavosurface margin
55. For the facial and lingual proximal walls in an inlay
cavity preparation for castings flares are used, which
are the flat or concave peripheral portions of the facial
and lingual walls
There are 2 types of flares
The primary flare
The secondary flare
The primary flare:
Is the conventional and basic part of the cavity
facially and lingually for an intra coronal preparation.
It is very similar to a long bevel formed of enamel and
part of dentin on the facial or lingual wall. Primary
flares also have a special angulation i.e., 450 to the
inner dentinal wall proper.
56. Functions and indications –
These design features perform the same function
as bevels.
They can bring the facial and lingual margins of the
cavity preparation to cleansable finishable areas.
They are indicated for any facial or lingual proximal
wall of an intracoronal cavity preparation.
57. SECONDARY FLARE
It is almost always a flat plane super imposed
peripherally to a primary flare. It is usually prepared
solely in enamel. Unlike primary flares, secondary
flares may have different angulations, involvement
and extent depending on their function
Functions and indications of secondary flare-
Lesions with wide bucco-lingual extensions
Contact areas too broad
99. CAPPING CUSPS
When the occlusal outline is extended up the cusp
slopes more than half the distance from primary
groove, capping the cusp should be considered.
If it is extended two thirds or more, capping is
necessary.
103. BOX
Introduced by Dr.G.V Black in which the proximal
cavities are prepared box shaped with buccal and
lingual walls and a definite gingival floor.
Advantages-
It has its own resistance and retention form.
Direct wax pattern can be made.
The outline form of the proximal surface can be
made on all types of teeth.
Minimum display of metal.
104. Disadvantages-
It involves removal of lots of tooth structure.
Clinically it is time consuming.
Narrow bevels leave a sharp edge and an undercut
gingivally , which cannot be satisfactorily
reproduced.
While taking impression distortions and breaking of
wax pattern occurs.
106. SLICE PREPARATION
This form of cavity is modified so that the proximal
surface is flat without definite side walls. This is
slice preparation which depends for its retention
mainly on the occlusal key, channels or locks cut in
the axial wall.
Historically ,a slice referred to the placement of
extra coronal taper using a disk of adequate
diameter to contact nearly the entire proximal
surface
107. INDICATIONS
As abutment in bridge work
Small carious lesion only on the middle of the
proximal surface.
To improve retention form.
Teeth with proximal undercuts can be eliminated
which facilitates taking impression.
Advocated for quadrant work where proximal
outline form can be rapidly developed.
For indirect wax pattern technique.
108. Advantages-
Less tooth structure is sacrificed.
Quicker and easier.
Well protected enamel margins.
Increases resistance and retention form by
exposing a larger amount of tissue surface to the
frictional grasp of the restoration.
109. Disadvantages-
Thoma(1951)pointed out that it displays
unnecessary amount of gold.
Reduced retention form.
Direct wax pattern cannot be made as
distinguishing between the margins is difficult.
The margins of metal which we’ll get are very thin
which can get distorted.
110. Slice preparation-
involves conservative
disking of the proximal
surface to establish the
buccal and lingual
extent of finish lines
and provide a lap joint
for finishing.
112. Auxiliary slice preparation-wraps partially around the
proximal line angles, thus providing additional tooth
support.
Resistance form is enhanced.
Provide external retention form.
113. MODIFIED FLARE
In view of the shortcomings of box type and slice
type preparations ,Barishman advocates a modified
preparation which may be called the box cum
gingival slice.
Modified flare is nothing but a combination of box
and slice preparation taking advantage of the box
preparation and slice preparation.
Minimum disking of the proximal walls is done for
better finishing and polishing
114.
115. TOOTH PREPARATION WITH SURFACE
EXTENSIONS
INDICATIONS-
Surface extensions are required to include facial or
lingual defects beyond the axial angle of the tooth.
Surface extensions are required to eradicate severe
peripheral Marginal undercuts, which have not been
removed by the maximum angulations and extent of
a secondary flare.
A surface extension is necessary to encompass an
axial angle for reinforcing and supporting reasons.
116. A surface extensions is needed to add to the
retentive capability of the restoration proximally
especially with shortened facial and lingual walls or
as a reciprocal means of retention
More surface extension is required to fulfil the
objectives of secondary flares in extremely wide
cavities or contact areas
117. REVERSE SECONDARY FLARES
Can be added to a cavity (tooth) preparation in lieu
of a secondary flare
The reverse secondary flare is in the form a partial
bevel. It involves only enamel with its maximum
depth at its junction with the main cavity
preparation. In ends on the facial or lingual surface
with a knife edge finishing line, and its extent
should not exceed the height of contour of the facial
or lingual surface in the mesio-distal direction nor
should it include the tip of the cusp.
118.
119. SKIRT
This is a more extensive surface extension than the
reverse secondary flare also superimposed on the
basic intracoronal inlay or onlay cavity preparation
facially and or lingually
INDICATIONS-
Skirting is required to involve defects with more
dimensions (especially depth) than those that can
be involve in a reverse secondary flare
A skirt is required to import resistance and retention
on a cast restoration in lieu of a missing or
shortened opposing facial or lingual walls.
120.
121. Skirting is necessary when the contact areas and
contour of the proximal surface are to be changed
Skirts are essential facially and lingually for tilted
teeth in order to restore the occlusal plane.
122. COLLAR
This type of surface extension is the most involving
surface wise and depth wise.
They are two types
a) Cuspal collars
b) Tooth collars
Cuspal collars which involve the facial or lingual
surface of one cusp only in a multi-cusped tooth.
Tooth collars involve the entire facial or lingual
surfaces of the tooth.
123. INDICATIONS
They help in retention and resistance when an
entire cusp is lost prior to the tooth preparation or
when it is necessary to remove if due to excessive
undermining.
They help retention in shortened teeth.
They help resistance and to enhance support for
tooth that is endodontically treated.
124.
125. CONCLUSION
Cast restorations form an integral link in the dental
restorative chain. They are an excellent choice in
many demanding situations. Understanding the
principles of tooth preparations and the intricacies of
cast restorations will enable the dentist to optimally
utilize this excellent option when the clinical situation
demands.
126. REFERENCES
Art and science of operative dentistry-Sturdevant
Principles and practice Operative Dentistry-
Charbeneau
Fundamentals of operative dentistry-Marzouk
Operative Dentistry-Summit
Atlas of inlays, onlays, crown and bridges-
Shillinberg
Inlays Crowns & Bridges-Cowell and Curson
Textbook of Operative Dentistry-Vimal Sikri