Gopi Krishna Conservative Dentistry Pdf Download
This manual provides step-by-step pictures and illustrations of the various laboratory exercises, which students have to learn and perform in their Ist and IInd year BDS course for the preclinical conservative dentistry and endodontics examination. This is the only book of its kind that would serve as a guide for learning as well as practicing the exercises on models in the preclinical laboratory. Segregated into ten well defined chapters, the book: - Provides synopsis of topics related to conservative dentistry and endodontics. - Includes clear description with illustrations of every instrument and equipment used. - Provides details regarding the composition, properties, uses and manipulation of the various dental materials. - Includes clear description with images of the phantom head and typodont teeth used in the preclinical laboratory along with a beginners pictorial guide in using the airotor and micromotor rotary instruments. - Discusses the various features, rules and fundamental of tooth preparation. - Provides step by step pictorial representation along with explanation of all laboratory plaster and typodont model exercises - Provides more than 200 commonly asked question to held students prepare for their viva voce examination along with the frequently asked spotters - Includes an exhaustive glossary of conservative dentistry and endodontic terms.
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Preclinical Manual of
Conservative Dentistry
and Endodontics
SECOND EDITION
V Gopikrishna MDS, FISDR
Vice Principal, Academics
Professor, Department of Conservative Dentistry and Endodontics
Thai Moogambigai Dental College and Hospital
Dr MGR Educational and Research Institute University
Chennai, INDIA
and
Founder Director
Root Canal Centre
Chennai (India) and Dubai (UAE)
CONTENTS
Contributors vii
Preface ix
Acknowledgements xi
Chapter 1 Synopsis of Conservative Dentistry 1
V Gopikrishna
Defi nition of Conservative Dentistry (Operative Dentistry) 1
Indications for Conservative Dentistry 1
Structure of Teeth and Supporting Tissues 2
Occlusion 15
Causes of Loss of Tooth Structure 23
Non-carious Destruction of Tooth 40
Chapter 2 Instruments and Equipment 45
V Gopikrishna and G Vijayalakshmi
Defi nition 45
Materials Used for Manufacturing Instruments 45
Classifi cation of Operative Dental Instruments 46
Parts of Hand Cutting Instruments 47
Instrument Nomenclature (According to GV Black) 50
Instrument Formula 50
Instrument Designs 53
Classifi cation of Instruments Based on their Usage 55
Instrument Grasps 70
Rests 72
Rotary Cutting Instruments 75
CONTENTS
xiv
Procedures for Forming Proper Contact and Contours 86
Separators 93
Wedges 94
Finishing and Polishing Materials 96
Equipment 98
Chapter 3 Dental Materials and their Manipulation 101
V Gopikrishna, G Vijayalakshmi, and I Porkodi
Rationale for Studying Dental Materials 101
Restoration 101
Properties of an Ideal Dental Restorative Material 103
Classifi cation of Dental Material 104
Dental Cements 106
Rules for Handling Dental Materials 107
Liners 109
Bases 113
Zinc Oxide Eugenol Cement 126
Mineral Trioxide Aggregate (MTA) 129
Biodentine 130
Dental Amalgam 131
Clinical Considerations in Amalgam Restorations 141
Adhesion to Tooth Structure 144
Smear Layer 146
Dental Adhesives (Bonding Agents) 147
Classifi cation of Dental Adhesives 147
Resin Composites 153
Pit and Fissure Sealants 159
Inlay Wax 160
Investment Materials 161
Dental Casting Alloys 163
Chapter 4 Know Your Operating Field 167
V Gopikrishna
Dental Chair 167
Phantom Head 167
Typodont Teeth 168
Instrument Tray 169
Compressed Air–Water Line 170
CONTENTS
xv
Three-Way Syringe 171
Cavity Holder 171
Beginners' Guide for Using Instruments and Equipment 172
Chapter 5 Fundamentals of Tooth Preparation and
Pulp Protection 191
V Gopikrishna
Introduction 191
Tooth Preparation 191
Nomenclature 192
GV Black's Classifi cation of Tooth Preparations 196
Objectives of Tooth Preparation 198
Initial Tooth Preparation Stages 199
Final Tooth Preparation Stages 213
Chapter 6 Preclinical Plaster Model Exercises 225
G Vijayalakshmi and V Gopikrishna
Introduction 225
Class I Tooth Preparation: Walls, Line Angles, and Point Angles 225
Class II Tooth Preparation: Walls, Line Angles, and Point Angles 251
Class III Tooth Preparation: Walls, Line Angles, and Point Angles
in Proximal Approach 274
Class IV Tooth Preparation: Walls, Line Angles, and Point
Angles—Proximal Approach 278
Class V Tooth Preparation: Walls, Line Angles, and Point Angles 282
Chapter 7 Preclinical Typodont Exercises 285
V Gopikrishna and G Vijayalakshmi
Preclinical Exercises 285
Class I Tooth Preparation for Amalgam Restoration 285
Class II Tooth Preparation for Amalagam Restoration 308
Ivory No. 1 Matrix and Retainer Placement 345
Class III Tooth Preparation for a Glass Ionomer Cement/
Composite Restoration 350
Class III Tooth Preparation ⫺ (Palatal Approach) ⫺
Glass Ionomer Cement Restoration 355
Class IV Tooth Preparation for Composite Restoration 357
Class V Tooth Preparation 361
CONTENTS
xvi
Tooth Preparation, Fabrication of Wax Pattern,
and Casting Procedure for Cast Metal Inlay 367
Fabrication of Wax Pattern and Casting Technique 373
Casting Defects 384
Chapter 8 Introduction to Preclinical Endodontics 387
V Gopikrishna
Endodontics 387
Pulp Cavity 387
Pulp Chamber 387
Root Canals 389
Tooth Anatomy and its Relation to the Preparation
of Access Opening 389
Goals of Access Cavity Preparation 396
Armamentarium for Access Cavity Preparation 396
Access Cavity Preparation of a Maxillary Central Incisor 397
Errors in Access Opening in Maxillary Anterior Teeth 400
Shaping and Cleaning of Radicular Space 400
Chapter 9 Common Viva Questions and Spotters 407
G Vijayalakshmi, E Sivapriya, and V Gopikrishna
Commonly Asked Viva Questions 407
Frequently Asked Spotters 439
Chapter 10 Glossary of Terms 451
M Abarajithan and V Gopikrishna
Anatomical Landmarks 451
Dental Caries 454
Noncarious Destruction of Teeth 455
Tooth Preparation and Nomenclature 455
Indirect Restorations 458
Instruments and Equipment 459
Properties of Dental Materials 461
Types of Dental Materials 463
Endodontics 468
V Gopikrishna
SYNOPSIS OF
CONSERVATIVE DENTISTRY
CHAPTER
1
"I keep six honest servingmen (they taught me all I knew); their names are What and
Why and When and How and Where and Who..."
— Rudyard Kipling
DEFINITION OF CONSERVATIVE DENTISTRY (OPERATIVE DENTISTRY)
According to Sturdevant, operative dentistry is the art and science of the diagnosis,
treatment, and prognosis of defects of teeth that do not require full coverage restora-
tions for correction. It involves the restoration of proper tooth form, function, and
aesthetics, while maintaining the physiologic integrity of the teeth in harmonious rela-
tionship with the adjacent hard and soft tissues. This fi eld of dentistry is also referred
to as conservative dentistry .
Patients seek dental treatment for symptoms, such as pain, sensitivity, trauma, decay,
bleeding gums, discolouration of teeth, and for aesthetic corrections. The management
of most of these problems is under the purview of this branch of dentistry. Hence,
operative dentistry/conservative dentistry forms the core of any dental practice.
Operative dentistry/conservative dentistry deals with:
• Prevention of dental diseases
• Interception of degenerative processes
• Preservation of the oral tissues
• Restoration of lost tooth structure
• Aesthetic correction of discoloured or malaligned teeth
INDICATIONS FOR CONSERVATIVE DENTISTRY
• Dental caries causing loss of tooth structure
• Noncarious loss of tooth structure
Attrition
Abrasion
Erosion
PRECLINICAL MANUAL OF CONSERVATIVE DENTISTRY AND ENDODONTICS
2
Abfraction
Developmental defects
• Traumatic injuries causing loss of tooth structure/s
• Aesthetic management/improvement of the colour and shape of teeth
• Repair or replacement of existing restorations.
STRUCTURE OF TEETH AND SUPPORTING TISSUES
A tooth has a crown portion seen clinically in the oral cavity and a root portion embe-
dded in a bony socket surrounded by the periodontium ( Fig. 1.1
).
Fig. 1.1 Component tissue and supporting structures of the tooth
Enamel
• It is the hardest substance of human body.
• It is a highly mineralized structure containing 95− 98% inorganic matter, predominantly
hydroxyapatite ( Fig. 1.2 ).
• It is translucent in nature ( Fig. 1.3 ).
SYNOPSIS OF CONSERVATIVE DENTISTRY
3
• Enamel provides the external shape to the tooth and protects the underlying dentin
and pulp.
• Enamel thickness varies from one set of tooth to another and is thicker at the incisal
or occlusal areas and becomes progressively thinner, till it terminates at the cemento-
enamel junction ( Fig. 1.4
).
Fig. 1.2 Prism and interprismatic enamel made
of hydroxyapatite ( Courtesy: Mathias Nordvi,
University of Oslo, Norway. From Sureshchandra
& Gopikrishna: Grossman's Endodontic Practice
13
th
edition, 2014, Wolters Kluwer)
Fig. 1.3 Translucency of enamel shown
Occlusal third
or
incisal third
Middle third
Gingival third
+24
o
–2
o
–2
o
+90
o
+90
o
htootroiretnAhtootroiretsoP
+24
o
Fig. 1.4 Variations in thickness and direction of enamel in human teeth
Dentin
• Dentin forms the largest portion of the tooth structure and is covered by enamel in
the crown portion and cementum in the root portion ( Fig. 1.5 ).
PRECLINICAL MANUAL OF CONSERVATIVE DENTISTRY AND ENDODONTICS
22
Figure 1.29 depicts both ADA universal and FDI nomenclature systems.
9
10
11
12
13
14
15
16
21 Central incisor
23 Canine
24 First premolar
25 Second premolar
26 First molar
27 Second molar
28 Third molar
38 Third molar
37 Second molar
36 First molar
35 Second premolar
34 First premolar
32 Lateral incisor
22 Lateral incisor
31 Central incisor
33 Canine
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
Maxillary arch
Outside numbers
FDI system
1
2
3
4
5
6
7
8
Maxillary arch
Mandibular
arch
11
12
13
14
15
16
17
18
48
47
46
45
44
43
42
41
Permanent dentition
roi
r
etsoP
Anterior
Anterior
Posterior
Inside numbers
Universal system
Fig. 1.29 Figure illustrating both the ADA universal nomenclature and FDI nomenclature systems
SYNOPSIS OF CONSERVATIVE DENTISTRY
23
CAUSES OF LOSS OF TOOTH STRUCTURE
The various causes of loss of tooth structure ( Fig. 1.30 ) are provided in Box 1.1 .
Restoration
integrity
Craze lines
Demineralization
Erosion/abrasion
Attrition
White spot
active or
arrested?
Plaque
Crack
Root caries
Cavitation
Fig. 1.30 Causes of loss of tooth structure
BOX 1.1 Causes of loss of tooth structure
• Dental caries
• Non-carious conditions
Tooth wear
Attrition
Abrasion
Abfraction
Erosion
Trauma
Developmental defects/malformation
Acquired developmental defects
• Enamel hypoplasia
• Dental fl uorosis
• Tetracycline staining
Hereditary conditions
• Hypodontia/Microdontia
• Amelogenesis imperfecta
• Dentinogenesis imperfecta
I. Dental Caries
Defi nition
Dental caries is defi ned as a multifactorial, transmissible, and infectious oral disease
caused primarily by the complex interaction of cariogenic oral fl ora (biofi lm) with fer-
mentable dietary carbohydrates on the tooth surface overtime.
• Dental caries is the most predominant cause of loss of tooth structure ( Fig. 1.31 ).
• It is an irreversible microbial disease of the calcifi ed tissues of the teeth characterized
by demineralization of the inorganic portions and dissolution of the organic portion.
Fig. 1.31 Dental caries occurring in the pits and fi ssures of a molar tooth
PRECLINICAL MANUAL OF CONSERVATIVE DENTISTRY AND ENDODONTICS
24
Factors causing dental caries ( Fig. 1.32 )
Caries is a multifactorial disease and the most important factors are
• Tooth (host)
• Cariogenic biofi lm
• Fermentable carbohydrates
• Time
DENTAL
CARIES
Cariogenic biofilm
during which
actors were
together
Tooth host
Fermentable
carbohydrates
other three
)
e period Tim
(
f
()
Fig. 1.32 Keyes Jordan diagram for dental caries—four essential factors for caries initiation
Pathophysiology of dental caries
Dental plaque or biofi lm is a tenaceous fi lm on the surface of teeth composed of bacte-
ria, like Streptococcus sanguis and Streptococcus mutans . These bacteria present in
plaque biofi lm ferment a suitable dietary carbohydrate substrate to produce acid causing
the plaque pH to fall. The critical pH for enamel and dentin is 5.5 and 6.2, respectively.
Repeated fall in pH below the critical pH overtime may result in demineralization of a
susceptible tooth structure. When the pH returns to neutral and when the concentration
of Ca and P supersaturated minerals gets added back to partially demineralized enamel,
remineralization starts. This demineralization–remineralization cycle is elaborated in
Box 1.2 . When the demineralization cycle overwhelms the ability of the host to remin-
eralize, then dental caries manifests clinically.
SYNOPSIS OF CONSERVATIVE DENTISTRY
25
BOX 1.2 Demineralization and remineralization cycle (From Gopikrishna: Sturdevant's Art and
Science of Operative Dentistry: A South Asian Edition, 2013, Elsevier)
I n Acid production: Cariogenic bacteria in the
biofi lm metabolize refi ned carbohydrates for en-
ergy and produce organic acid by-products.
II n Critical biofi lm pH: These organic acids, if
present in the biofi lm ecosystem for extended
periods, can lower the pH in the biofi lm to below
a critical level (5.5 for enamel, 6.2 for dentin).
III n Demineralization: The low pH drives calcium
and phosphate from the tooth to the biofi lm in an
attempt to reach equilibrium, hence resulting in a
net loss of minerals by the tooth or demineralization .
IV n Remineralization: When the pH in the
biofi lm returns to neutral and the concentration
of soluble calcium and phosphate is supersatu-
rated relative to that in the tooth, mineral can
then be added back to partially demineralized
enamel, in a process called remineralization .
V n Demineralization and remineralization
cycle: This process takes place several times a
day over the life of the tooth and is modulated by
many factors, including:
Number and type of microbial fl ora in the biofi lm
Diet
Oral hygiene
Genetics
Dental anatomy
Use of fl uorides and other chemotherapeutic
agents
Salivary fl ow and buffering capacity
Inherent resistance of the tooth structure and
composition that will differ from person to
person, tooth to tooth, and site to site.
VI n Progression of disease: Repeated deminer-
alization events may result from a predominantly
pathologic environment causing the localized dis-
solution and destruction of the calcifi ed dental
tissues, evidenced as a caries lesion or a 'cavity'.
Severe demineralization of enamel results in the
formation of a cavitation in the enamel surface.
Subsequent demineralization of the inorganic
phase and denaturation and degradation of the
organic phase result in dentin cavitation.
BOX 1.3 Caries lesion—defi nitions
Caries lesion: Tooth demineralization as a result of
the caries process. Other texts may use the term
carious lesion . Laypeople may use the term cavity .
Smooth surface caries: A caries lesion on a
smooth tooth surface.
Pit-and-fi ssure caries: A caries lesion on a pit-
and-fi ssure area.
Occlusal caries: A caries lesion on an occlusal
surface.
Proximal caries: A caries lesion on a proximal
surface.
Enamel caries: A caries lesion in enamel, typi-
cally indicating that the lesion has not penetrated
into dentin (Note that many lesions are detected
clinically, as enamel caries may very well have
extended into dentin histologically).
Dentin caries: A caries lesion into dentin.
Coronal caries: A caries lesion in any surface of
the anatomic tooth crown.
Root caries: A caries lesion in the root surface.
Primary caries: A caries lesion not adjacent to an
existing restoration or crown.
Secondary caries: A caries lesion adjacent to an
existing restoration, crown, or sealant. Other
term used is caries adjacent to restorations and
sealants (CARS) . It is also referred to as recurrent
The common terms used in this manual to defi ne caries lesions is provided in
Box 1.3 .
Continued
PRECLINICAL MANUAL OF CONSERVATIVE DENTISTRY AND ENDODONTICS
32
ii. Cavitated enamel caries Cavitated
enamel lesions can be initially detected
as subtle breakdown of the enamel sur-
face. These lesions are very sensitive to
probing and can be easily enlarged by us-
ing sharp explorers and excessive probing
force. More advanced cavitated enamel
lesions are more obviously detected as
enamel breakdown.
BOX 1.5 Remineralization mechanism of a white spot lesion (WSL)
The supersaturation of saliva with calcium and
phosphate ions serves as the driving force for the
remineralization process
Non-cavitated enamel lesions retain most of the
original crystalline framework of the enamel
rods, and the etched crystallites serve as nucleat-
ing agents for remineralization
Calcium and phosphate ions from saliva can pen-
etrate the enamel surface and precipitate on the
highly reactive crystalline surfaces in the enamel
lesion
The presence of trace amounts of fl uoride ions dur-
ing this remineralization process greatly enhances
the precipitation of calcium and phosphate, result-
ing in the remineralized enamel becoming more
resistant to subsequent caries attack, because of
the incorporation of more acid-resistant fl uorapa-
tite
Remineralized (arrested) lesions can be observed
clinically as intact, but discoloured, usually
brown or black, spots. The change in colour is
presumably caused by trapped organic debris and
metallic ions within the enamel. These discol-
oured and remineralized arrested caries areas are
intact and are more resistant to subsequent car-
ies attack than the adjacent unaffected enamel.
They should not be restored, unless they are aes-
thetically objectionable.
Clinical Note
This stage cannot be remineralized and
the carious lesion has to be removed and
the tooth restored with an appropriate
restoration.
Fig. 1.41 CPITN probe: Community Periodon-
tal Index for treatment needs probe ( Courtesy:
Hu-Friedy Mfg. Co. From Gopikrishna: Sturdevant's
Art and Science of Operative Dentistry: A South
Asian Edition, 2013, Elsevier)
PRECLINICAL MANUAL OF CONSERVATIVE DENTISTRY AND ENDODONTICS
36
II. Reaction to a moderate-intensity attack: Reparative dentin formation The sec-
ond level of dentinal response is to moderate-intensity irritants , by forming reparative
dentin ( Box 1.6 ) .
BOX 1.7 Mechanism of pulpal necrosis
Small, localized infections in the pulp produce an
infl ammatory response involving capillary dila-
tion, local oedema, and stagnation of blood fl ow
As the pulp is contained in a sealed chamber,
and its blood is supplied through narrow root
canals, any stagnation of blood fl ow can result
in local anoxia and necrosis
The local necrosis leads to more infl ammation,
oedema, and stagnation of blood fl ow in the
immediately adjacent pulp tissue, which be-
comes necrotic in a cascading process that
rapidly spreads to cause entire pulpal necrosis
BOX 1.6 Mechanism of reparative dentin
formation
Infected dentin contains a wide variety of
pathogenic materials or irritants , including
high acid levels, hydrolytic enzymes, bacteria,
and bacterial cellular debris.
The pulp may be irritated suffi ciently from high
acid levels or bacterial enzyme production to
cause the formation (from undifferentiated
mesenchymal cells) of replacement odonto-
blasts (secondary odontoblasts)
These cells produce reparative dentin (reac-
tionary dentin) on the affected portion of the
pulp chamber wall
Clinical Note
i. This dentin is different from the normal dentinal apposition that occurs through-
out the life of the tooth by primary (original) odontoblasts.
ii. The structure of reparative dentin varies from well-organized tubular dentin (less
often) to very irregular atubular dentin (more often), depending on the severity of
the stimulus.
iii. Reparative dentin is an effective barrier to diffusion of material through the tubules
and is an important step in the repair of dentin.
iv. Severe stimuli also can result in the formation within the pulp chamber of unattached
dentin, termed pulp stones , in addition to reparative dentin.
v. The pulpal blood supply may be the most important limiting factor for the pulpal
responses.
III: Reaction to severe, rapidly advancing caries characterized by very high acid
levels: Pulpal necrosis and periradicular progression of disease
The third level of
dentinal response is to severe irritation. Acute, rapidly advancing caries with high levels
of acid production overpowers dentinal defences and results in infection, abscess, and
death of the pulp ( Box 1.7 ).
SYNOPSIS OF CONSERVATIVE DENTISTRY
37
Clinical Note
i. Maintenance of pulp vitality depends on the adequacy of pulpal blood supply.
ii. Recently erupted teeth with large pulp chambers and short, wide canals with large
apical foramina have a much more favourable prognosis for surviving pulpal infl am-
mation, than fully formed teeth with small pulp chambers and small apical foramina.
Bacterial plaque
Zone 1 : Normal
dentin
Zone 3 : Infected
dentin (outer
carious dentin)
Zone 2: Affected
dentin (inner
carious dentin)
Fig. 1.45 Dentinal caries with outer infected dentin and inner affected dentin
Zones of dentin caries Three different zones have been described in carious dentin
( Fig. 1.45 ).
Zone 1: Normal dentin
• The deepest area is normal dentin , which has tubules with odontoblastic processes
that are smooth and no crystals are present in the lumens.
• The intertubular dentin has normal cross-banded collagen and normal dense apatite
crystals.
• No bacteria are present in the tubules.
• Stimulation of dentin (e.g. by osmotic gradient [from applied sucrose or salt], a bur,
a dragging instrument, or by desiccation from heat or air) produces a sharp pain.
Zone 2: Affected dentin
• Also called inner carious dentin , affected dentin is a zone of demineralization of
intertubular dentin and of initial formation of fi ne crystals in the tubule lumen at
the advancing front.
• Damage to the odontoblastic process is evident.
• Affected dentin is softer than normal dentin and shows loss of mineral from intertu-
bular dentin and many large crystals in the lumen of the dentinal tubules.
• Stimulation of affected dentin produces pain.
• Although organic acids attack the mineral and organic contents of dentin, the colla-
gen cross-linking remains intact in this zone.
• The intact collagen can serve as a template for remineralization of intertubular dentin
and this region remains capable of self-repair, provided that the pulp remains vital.
• The affected dentin zone can also be subclassifi ed into three subzones:
a. Subtransparent dentin
b. Transparent dentin
c. Turbid dentin
V Gopikrishna and G Vijayalakshmi
INSTRUMENTS AND
EQUIPMENT
CHAPTER
2
DEFINITION
Instrument
Instruments are small hand-held devices that are used for various procedures while
treating a patient, e.g. mouth mirrors, probes, dressing plier, and condensers.
Equipment
Equipment are larger devices that aid the clinician while treating a patient, e.g. dental
chair, operating stool, X-ray unit, and amalgamator.
MATERIALS USED FOR MANUFACTURING INSTRUMENTS
1. Carbon steel: They contain 0.51.5% carbon in iron. They are harder and sharper
than stainless steel, but tend to corrode and are prone for fracture.
2. Stainless steel:
a. Pure stainless steel: They are alloys comprising of 7085% iron, 1525% of
chromium, and 1 2 % of carbon. They are the most commonly used material
for the manufacture of dental instruments. Their main disadvantage is their
tendency to lose their sharpness due to repeated usage.
b. Stainless steel with te fl on/titanium nitride coating: These are instruments
which are specifi cally used for the placement and handling of dental composites.
The advantage is that the composite does not stick to this coating and make
the placement of composites simplifi ed.
3. Carbide inserts: Some instruments are made with carbide inserts to provide more
durable cutting edges.
'A man who works with his hands is a . . . Labourer
A man who works with his hands and his brain is a . . . Craftsman
But a man who works with his hands and his brain and his heart is an Artist' .
—Louis Nizer
PRECLINICAL MANUAL OF CONSERVATIVE DENTISTRY AND ENDODONTICS
46
4. Others: Other alloys of titanium, nickel, cobalt, or chromium are used in the
manufacture of hand instruments.
CLASSIFICATION OF OPERATIVE DENTAL INSTRUMENTS
Instruments are broadly classifi ed as:
1. Hand instruments: These are manually used instruments.
2. Rotary instruments: These are engine-driven instruments.
The most commonly employed classifi cations for hand instruments are given in Box 2.1 .
BOX 2.1 Classifi cation of operative dental instruments
I. Sturdevant's classi fi cation
A. Cutting instruments
i. Excavators
• Ordinary hatchets
• Hoes
• Angle formers
• Spoons
ii. Chisels
• Straight chisel
• Curved chisel
• Binangle chisel
• Enamel hatchet
• Gingival marginal trimmer
iii. Others
• Knives
• Files
• Scalers
• Carvers
B. Noncutting instruments
• Amalgam condensers
• Mirrors
• Explorers
• Probes
II. GV Black's classifi cation
This classifi cation is based on the use of the in-
strument.
1. Cutting instruments
A. Hand
• Chisels
• Excavators
• Hatchets
• Hoes
B. Rotary
• Burs
• Stones
• Discs
2. Condensing instruments
• Pluggers
• Hand
• Mechanical
3. Plastic instruments
• Spatulas
• Cement carriers
• Carvers
• Plastic fi lling instruments
• Burnishers
4. Finishing and polishing instruments
A. Hand
• Orangewood sticks
• Polishing points
• Finishing strips
B. Rotary
• Finishing brushes
• Mounted brushes
• Mounted stones
• Rubber cups
5. Isolation instruments
• Rubber dam kit (frame, clamps, sheet,
forceps, and punch)
• Saliva ejector
• Cotton roll holder
• Evacuator tips and equipment
6. Miscellaneous instruments
• Mouth mirror
• Explorers
• Probe
• Pliers
• Scissors
• Others
PRECLINICAL MANUAL OF CONSERVATIVE DENTISTRY AND ENDODONTICS
56
2. i. Plane mirror: This is the more commonly used mirror, which provides distortion-
free images.
ii. Concave surface: This provides various degrees of magnifi cation. The drawback
is its tendency to distort the image view.
3. i. One-sided mirror: Mirror is placed on one side of the circular metal disc with
the reverse side being made of the
metal.
ii. Twin-sided: Both sides have mirrors
that aid in indirect vision even while
retracting tissues ( Fig. 2.12 c).
2. Explorer
Explorer is mainly a diagnostic instrument
that is formed of three parts, namely handle,
shank, and an exploring tip.
The most common explorers used clinically
in operative dentistry are:
i. Straight explorer: This explorer has a
mild curvature near the exploring tip
( Fig. 2.13 a).
ii. Arch explorer (Shepherd's hook): This
has a semicircle or an arch-shaped
working end with exploring tip at right
angle to the handle ( Fig. 2.13 b).
iii. Interproximal explorer (Briault's
probe): In this explorer, the shank has
two or more angles and the exploring
tip is used for ( Fig. 2.13 c):
•
Detecting proximal carious lesion.
•
Assessing marginal fi t of restorations.
•
Removing excess restorative materi-
al, while shaping the occlusal embra-
sure in proximal cavities.
3. Probes
• Probes are used in restorative dentistry to
determine the dimensions and features of
preparations and restorations.
• The three most common probes employed are:
i. Williams probe: This is characterized
by a lack of marking at the 4th and the
6th mm.
(a) (b) (c)
Fig. 2.13 (a) Straight explorer; (b) Arch
explorer (Shepherd's hook); (c) Interproximal
explorer (Briault's probe) ( Courtesy: Hu-Friedy
Mfg. Co.)
Fig. 2.12 (a) Front surface mirror; (b) Back
surface mirror; (c) Double-sided mirror
(c)
(b)
(a)
INSTRUMENTS AND EQUIPMENT
57
Clinical Note
The main differences in these probe designs are
based upon:
i. Position of the millimetre markings.
ii. Differences in the diameters.
iii. Confi guration of the markings (notched or
painted).
ii. CPITN probe (Community Periodontal Index
for Treatment Needs probe): This probe has
a 0.5 mm ball-ended probe tip with a colour
coding between 3.5 and 5.5 mm markings
( Fig. 2.14 a).
iii. UNC 12 probe (University of North Carolina
probe) ( Fig. 2.14 b).
4. Dressing Plier
Dressing plier also known as dental tweezer is a
diagnostic instrument useful in carrying things to
and from the mouth ( Fig. 2.15 a).
This instrument has two arms with angled tips which is used for:
• Grasping or transferring materials in and out of the oral cavity.
• Placing and removing cotton rolls for isolation of the cavity.
• Placing cotton pellets for drying the cavity.
One of the modifi cations of the dressing plier is the locking plier.
Locking plier
• Locking plier has a lock in the middle, that clips the two beaks fi rmly against each
other ( Fig. 2.15 b).
• It helps in avoiding slippage of anything carried.
II. Cutting Instruments
1. Excavators
i. Ordinary hatchet (bibevelled)
ii. Hoe excavator
iii. Angle formers
iv. Spoon excavator
a. Cleoid excavator
b. Discoid excavator
(a) (b)
Fig. 2.14 Probes: (a) CPITN probe; (b)
UNC 12 probe (Courtesy: Hu-Friedy
Mfg. Co.)
INSTRUMENTS AND EQUIPMENT
67
• The working ends of certain plastic instruments are coated with titanium or titanium
aluminium nitride, so that the composite resin does not stick on to the instrument
( Fig. 2.31 c).
• They help both in carrying and placement of the composite resins on to the tooth
structure.
iv. Amalgam carriers
• Amalgam carriers are used to insert the mixed amalgam into the prepared cavity.
• They have a hollow cylinder into which the triturated dental amalgam can be loaded
( Fig. 2.32 ).
• Both single- and double-ended carriers are available.
• Double-ended carriers are plunger-operated with a fi nger lever that pushes the
amalgam into the prepared cavity.
• Available in various sizes: Mini, regular, large, and jumbo.
c
(a)
(b)
Fig. 2.31 (a and b) Clinical application of the plastic instrument; (c) Plastic instrument ( Courtesy: Hu-Friedy
Mfg. Co.)
(a) (b)
Fig. 2.32 (a) Amalgam carrier with a fi nger plunger ( Courtesy: Hu-Friedy Mfg. Co.); (b) Traditional
amalgam carrier
PRECLINICAL MANUAL OF CONSERVATIVE DENTISTRY AND ENDODONTICS
68
v. Condensers
• Condensers are used for compacting amalgam or direct gold into the prepared cavity
( Fig. 2.33 ).
• They can also be used to push glass ionomer cement or resin composite into the pre-
pared cavity.
• The working ends or nibs of the condensers may be round, triangular, parallelogram,
or elliptical in shape.
• The most commonly used ones have a round shape with a fl at end (face). Flat-faced
round condenser allows maximum condensation pressure ( Fig. 2.33 a).
• They can also be used in narrow or conservative cavities (contours of regular con-
denser faces are usually fl at, concave, and angular faces provide convenience in
buccal and lingual surfaces).
(a)
(b)
c
Fig. 2.33 Condensers: (a) Round-shaped condensers with fl at ends; (b) Rectangular-shaped condensers
with fl at ends; (c) Diamond-shaped condensers with fl at ends ( Courtesy: Hu-Friedy Mfg. Co.)
vi. Carvers
Carvers are used to shape amalgam and resin composite materials after they have been
placed in the tooth preparation ( Fig. 2.34
).
a. Hollenback carver or Wards C carver:
•
Double-ended binangled instrument, which is used to remove excess amalgam
and shape amalgam to the natural tooth contour ( Fig. 2.34 a).
•
It is also used for carving inlay wax during fabrication of inlays and onlays.
b. Diamond carver or Frahm's carver: Bibevelled cutting edges used primarily for
occlusal carving of amalgam restorations ( Fig. 2.34 b).
c. Cleoid–discoid carver: Also used primarily for occlusal carving of amalgam
restorations ( Fig. 2.35 ).a
d. Walls no. 3 carver: It is useful for carving occlusal surfaces and for carving facial
and lingual surfaces of large amalgam restorations ( Fig. 2.34 c).
e. Interproximal carver (IPC): It has very thin blades and is valuable for carving
proximal amalgam surfaces near the interproximal contact area ( Fig. 2.34 d).
INSTRUMENTS AND EQUIPMENT
69
vii. Burnishers
• Burnishing is defi ned as the process to make a material shiny or lustrous, especially
by rubbing.
• They are used to make the surface of the restoration smooth, shiny, and polished.
• They are also used to contour metal bands, so as to provide the desired contours of
the restoration.
• They are double-ended instruments with angulated shanks.
• Nibs are smooth-faced and has different shapes: Ball-shaped, egg-shaped, or conical-
shaped ( Fig. 2.36
).
(a)
(b)
(c)
(d)
Fig. 2.34 (a) Hollenback carver; (b) Diamond carver or Frahm's carver; (c) Walls no. 3 carver;
(d) Interproximal carver (IPC) ( Courtesy: Hu-Friedy Mfg. Co.)
(a)
(b)
Fig. 2.35 Cleoid discoid carver: (a) Cleoid end; (b) Discoid end. They are useful for carving the
occlusal surfaces of amalgam restorations
INSTRUMENTS AND EQUIPMENT
89
3
6 5 4 2 1
Fig. 2.63 Toffl emire matrix retainer: (1) Smaller outer nut; (2) Larger inner nut; (3) Rotating spindle;
(4) Frame; (5) Guide slot; (6) Head
d. Frame: Holds the parts of the matrix retainer together.
e. Guide slot: Diagonal slot where the matrix band is placed and is secured by the
spindle.
f. Head: It accommodates the matrix band and is U shaped. It has a closed end and
an open end which contains the guide slot. The open end of this outer guide slot
should be held facing the operator while insertion of the matrix band into the
retainer and should always be facing gingivally during the insertion of the matrix
around the tooth.
Types Different types of Toffl emire retainer available are:
• Universal/straight
• Contra-angle
• Contra-angle junior
Types of bands ( Fig. 2.64 )
a. No. 1 Toffl emire band: Also referred to as the universal band.
b. No. 2 Toffl emire band: Also called as the MOD bands, two extensions projecting at
its gingival edge to allow matrix application in teeth with very deep gingival margins
in the proximal aspects of the tooth.
c. No. 3 Toffl emire band: It is also used for MOD cavities and has deeper gingival
margins.
4. Compound-supported matrix
• Custom-made matrix/anatomical matrix.
• Employs 5/16 inch wide, 0.002 inch thick stainless steel band cut to a length such
that it wraps around the one-third of the facial and lingual side beyond the prepared
proximal side.
PRECLINICAL MANUAL OF CONSERVATIVE DENTISTRY AND ENDODONTICS
90
(a)
(b)
dnab erimelffoT 2.oNdnab erimelffoT 1.oN
(c)
No.3 Tofflemire band
Fig. 2.64 Different types of Toffl emire bands
• Band is wedged and stabilized by applying softened impression compound facially,
lingually, and occlusally on the adjacent tooth.
5. T-band matrix ( Fig. 2.65 )
• Preformed T-shaped stainless steel matrix band is used without a retainer.
• Long arm is bent to surround the tooth and it overlaps the short arm, which is then
bent over the long arm and thus retains the shape.
• Band is supported by wedging and low-fusing compound.
6. Precontoured matrix Small, precontoured dead soft metal matrices in various
sizes are held in place by a fl exible metal ring. It is used for both amalgam and
Threads
(a)
(b)
(c)
(d)
(e)
(f)
(g)
Fig. 2.65 (a) T-band; (b) Folding one arm of T; (c) Folding another T and making a small loop; (d) Fold-
ing of longer arm of T; (e) Longer entering the loop formed by smaller arms making a band; (f) Buccal
view of T-band around the molar teeth after trying the thread; (g) Bucco-occlusal view of banded molar
INSTRUMENTS AND EQUIPMENT
91
composite restorations, e.g. Palodent bitine matrix system, and Composi-tight matrix
system ( Figs 2.66 and 2.67 ).
Fig. 2.67 Bitine ring placed to stabilize and
retain the sectional matrix
Fig. 2.66 Sectional matrix placed in a class II
cavity in a maxillary fi rst molar
7. Copper band matrix
• Various sizes are available and are selected according to the diameter of the tooth.
• Used in badly broken down teeth, especially those receiving pin amalgam restorations
and complex class II cavities.
• Provides excellent contour, but it is time-consuming.
8. Automatrix
• Retainerless matrix system indicated for complex amalgam restorations ( Fig. 2.68 ).
• It has:
a. Automatrix bands of various thickness and selected according to the height of the
tooth.
Fig. 2.68 Automatrix
V Gopikrishna, G Vijayalakshmi, and I Porkodi
DENTAL MATERIALS AND
THEIR MANIPULATION
CHAPTER
3
RATIONALE FOR STUDYING DENTAL MATERIALS
1. To understand the properties and behaviour of dental materials.
2. To be able to handle and manipulate the materials properly.
3. To be able to access and use the appropriate material for the given clinical
condition.
4. To be able to educate patients.
RESTORATION
Restoration of teeth is done to remove diseased tissue and to restore form, function,
and appearance.
Choice of Restoration
It is based on:
• The tooth to be restored (anterior/posterior)
• Surface of the tooth to be restored (occlusal/buccal/proximal)
• Amount of destruction of the tooth structure
Classication of Restoration
Restoration can be classied based on many criteria.
I. Based on fabrication
• Direct restoration
Restorative material placed directly into the cavity, e.g. amalgam, composite, and
glass ionomer cement.
'Education is what remains after one has forgotten what one has learned in school'.
— Albert Einstein
Dental Materials anD tHeir ManiPulation
105
I. Based on their Composition (Box 3.1)
BOX 3.1 Classification of dental materials based on their composition
Inorganic salts
Crystalline
ceramics
Glasses
Alloys
Intermetallic
compounds
Rigid polymers
Waxes
Elastomers
Polymers
Composites
Metals
Ceramics
Dental
materials
i. Ceramics
Ceramics are chemical mixtures of metallic and non-metallic elements, which form ionic
bonding or covalent bonding. Most of them are semi-crystalline silicates and oxides, like
Al
2
O
3
.
ii. Metals
Metal is an opaque lustrous chemical substance that is a good conductor of heat and
electricity.
Metal alloy: It is a chemical mixture of metallic elements producing more than one
phase, e.g. dental amalgam alloy; cast noble alloy, and base metal alloy.
iii. Polymers
Polymers are long molecules composed principally of non-metallic elements that are
chemically bonded by covalent bonds.
Dental Materials anD tHeir ManiPulation
115
Composition of GIC (Table 3.2)
Fig. 3.8 Type II–An aesthetic restorative glass ionomer cement (Courtesy: Shofu)
Powder
(aluminosilicate powder containing
calcium and fluoride)
Liquid
(polyacrylic acid copolymerized
with other acids)
Silica — 35–40 %
Alumina — 20–30 %
Calcium uoride — 15–20 %
Aluminium uoride — 1.5–2.5 %
Aluminium phosphate — 9.8%
Sodium uoride — 5%
Polyacrylic acid — 40–50 %
Itaconic acid, maleic acid, tartaric acid — 5%
Water — 45–50%
Table 3.2 Composition of GIC
Manipulation (Fig. 3.9)
• Powder and liquid are dispensed on to a paper pad.
• Powder should be incorporated rapidly into liquid.
• Use of plastic spatula is recommended.
• Mixing time not to exceed 45260 s.
• The nal mix should have a glossy surface.
• The working time is about 2 min.
• Final setting time is 7 min.
Dental Materials anD tHeir ManiPulation
117
Setting reaction of GIC (Box 3.3 and Fig. 3.10)
BOX 3.3 Setting reaction of glass ionomer cement
The acidic liquid solution (pH 5 1) dissolves portions of the periphery of the silicate glass particle,
releasing calcium, aluminium, uoride, silicon, and other ions.
Calcium ions are chelated quickly by carboxyl side groups on polyacrylic acid polymer chains. The same
carboxylic acid side groups also are capable of chelating surface ions on the calcium ions from the tooth
structure
Cross-linking of the polyacrylic acid chains takes place producing an amorphous polymer gel.
During the next 24 to 72 h, the calcium ions are replaced by more slowly reacting aluminium ions to
produce a more highly cross-linked matrix that is now mechanically stronger.
It is now believed that during the maturation involving aluminium ion cross-linking, silicon ions and
unbound water participate in producing an inorganic co-matrix, best described as a hydrated silicate.
This process generates true chemical bonds at all internal and external interfaces when the reaction
conditions are correct (Fig. 3.10)
F
F
F
F
F
F
Ca
++
Ca
++
AI
++
Ca
++
CO CO
–
CO CO
–
CO CO
–
CO CO
–
CO CO
–
–
O CO
–
O CO
–
O CO
–
O CO
–
O CO
–
O CO
–
O CO
–
O CO
++
Ca–
++
Ca–
++
Ca–
++
Ca
++
Ca
–
3
4
PO
–
3
4
PO
–
3
4
PO
–
3
4
PO
Polyacrylate displaces
phosphate and calcium
Polyacid monomers
Polyacid copolymer matrix
Ionic interaction
Tooth structure
CO O
–
CO O
–
CO O
–
CO O
–
CO O
–
Fig. 3.10 Setting reaction and chemical bonding of glass ionomer cement to the tooth structure
Dental Materials anD tHeir ManiPulation
121
described as composites to which some glass ionomer components have been added
(Box 3.4).
• It contains a dimethacrylate monomer and an ion leachable glass.
5. Calcium aluminate GIC
• Hybrid cement made of calcium aluminate and GIC.
• Indicated as luting cement for xed prosthesis.
• Powder contains calcium aluminate, polyacrylic acid, tartaric acid, strontium-
uoro-alumino glass, and strontium uoride.
• Liquid contains water and additives.
Glass Ionomer–Composite Continuum (Fig. 3.15 and Table 3.3)
BOX 3.4 Comparison of RMGIC with compomer
RMGIC Compomer
Display acid base reaction and chemical behav-
iour of traditional glass ionomer cements
HEMA (hydroxyethyl methacrylate) or dimethyl
methacrylate is added to the polyacid
Chemical bonding with the tooth similar to GIC
Polymer-based composites that have been
slightly modied to permit uoride release from
glass matrix phase
Contains a dimethacrylate monomer and an ion
leachable glass
They require a dentin bonding agent after acid
etching of the substrate for micromechanical
bonding with the tooth
Glass-ionomer
cements
Resin-modified
glass ionomers
(hybrid ionomers)
Compomers
(polyacid-modified
resin composites)
Resin composites
(glass containing
hydrophobic resins
Fuji I, Fuji II, Fuji IX,
Ketac Fil, Ketac Cem,
Shofu I, Shofu II
Vitrebond, Vitremer XR
ionomer, Fuji Liner LC,
Fuji II LC, Fuji plus,
Photac Fil Photac Bond
Dyract, Variglass,
Geristore Compoglass
F, Resinomer, F2000
Charisma, Prodigy
Tetric Ceram,
TPH, Z350,
Ceram X Mono
Fig. 3.15 Glass ionomers and composite resins are the two different kinds of direct tooth-coloured
restorative materials. Resin-modified glass ionomer is basically a glass ionomer with a little composite
resin integrated into it while a compomer is basically a composite with little glass ionomer integrated
into it
Preclinical Manual of conservative Dentistry anD enDoDontics
122
II. Zinc Polycarboxylate Cement Fig.3.16
Its ADA specication number is 96 and its composition is provided in Box 3.5.
Sturdevant's Art and Science of Operative Dentistry: A South Asian Edition, 2013, Elsevier)
Material's
class
Flexural
strength
(MPa)
Flexural
modulus
(GPa)
Compressive
strength (MPa)
Diametral tensile
strength (MPa)
Shear bond
strength
(MPa)
Shrinkage
(% vol)
Conventional
glass ionomer
25 8 85–90 22225 325 3
Resin-modied
glass ionomer
35270 4 1702200 35240 8214 3.5
Compomer 97 628 2102245 45247 14 4.5
Resin
composite
140 18 2002350 65275 24228 3
Table 3.3 Mechanical properties of glass ionomers and resin composite (From Gopikrishna:
Fig. 3.16 Zinc polycarboxylate cement (Courtesy: Shofu)
BOX 3.5 Composition of zinc polycarboxylate
Powder Liquid
Zinc oxide − 90%
Magnesium oxide − 10% (stannic oxide may be
substituted in the place of magnesium oxide)
Bismuth oxide
Aluminium oxide
Polyacrylic acid − 40%
Itaconic acid
The composition of zinc polycarboxylate is provided in Box 3.5
Preclinical Manual of conservative Dentistry anD enDoDontics
132
Materials
(abbreviation) Liquid
Powder
components Reaction type
Reaction product
matrix
Setting time
(min)
Retention
Compressive
strength(mpa) Pulp response Advantages Disadvantages
Unmodied ZOE
(ZOE)
Eugenol ZnO Acid-base
reaction
Crystalline zinc
eugenolate
4-10
Mechanical 6-28 pH57 PULP
SEDATIVE
BIOCOMPATIBLE
OBTUNDENT
EFFECT
LOW STRENGTH
Higher SOLUBILITY
AND DISINTEGRATION
Resin-reinforced
ZOE (R-ZOE)
Eugenol ZnO, polymer,
resin
Acid-base
reaction
Crystalline zinc
eugenolate
5
Mechanical 48 Similar to ZOE Good initial sealing
and adequate
strength for nal
cementation of
restorations
LOW STRENGTH
Higher SOLUBILITY
AND DISINTEGRATION
EBA-modied ZOE
(ZOE-EBA)
Eugenol,
EBA
ZnO, Al
2
O
3
,
polymer
Acid-base
reaction
Crystalline zinc
eugenolate,
crystalline zinc
ethoxybenzoate
Mechanical 55 Similar to ZOE Long working time,
good ow and low
irritation to pulp
Hydrolytic
breakdown, plastic
deformation, poorer
retention
Zinc phosphate(ZP) H
3
PO
4
,
H
2
O
ZnO Acid-base
reaction
Crystalline tertiary
zinc phosphate
5.5
Mechanical 104 IRRITANT HIGH ELASTICITY PULP IRRITANT NO
BONDING NO ANTI-
CARIOGENICITY
Polycarboxylate(PC) PAA, H
2
O ZnO Acid-base
reaction
Amorphous zinc-
polyacrylate gel
6-9
Chemical 55 MILD (LARGE
MOLECULAR
SIZE)
CHEMICAL
BONDING
LESS PULP
IRRITANT
LESS WORKING TIME
Conventional GI (GI) PAA, H
2
O F-Al-Si glass Acid-base
reaction
Amorphous
aluminopolyacrylate
gel
7
Chemical 86 MILD FLUORIDE
RELEASE
CHEMICAL
BONDING
Initial slow setting
Moisture sensitive
Resin-modied GI
(RMGI)
PAA, H
2
O,
water-
soluble
monomers
F-Al-Si glass Light and
chemically
activated
polymerization
and acid-base
reaction
Amorphous
aluminopolyacrylate
gel, cross-linked
polymer
4
Chemical 170—200 Mild to
moderate
Control set, uoride
release, high exural
strength.
More microleakage
Compomer (CM) Monomers F-Al-Si glass Light-activated
polymerization
Amorphous cross-
linked polymer,
aluminopolyacrylate
gel
Command
set by light
activation
MICRO-
MECHANICAL
210—245 Moderate Fluoride release Cannot be used for
stress-bearing areas.
Composite (or resin)
(CP)
Monomers Silicate glass Light /
chemically
activated
poymerization
Amorphous cross-
linked polymer
Command
set by light
activation
MICRO-
MECHANICAL
200—350 Moderate MICRO-
MECHANICAL
BONDING
Polymerization
shrinkage Technique
sensitive
Table 3.6 Summary of dental cement classifications, abbreviations, reactants, and reaction products
Dental Materials anD tHeir ManiPulation
133
Materials
(abbreviation) Liquid
Powder
components Reaction type
Reaction product
matrix
Setting time
(min)
Retention
Compressive
strength(mpa) Pulp response Advantages Disadvantages
Unmodied ZOE
(ZOE)
Eugenol ZnO Acid-base
reaction
Crystalline zinc
eugenolate
4-10
Mechanical 6-28 pH57 PULP
SEDATIVE
BIOCOMPATIBLE
OBTUNDENT
EFFECT
LOW STRENGTH
Higher SOLUBILITY
AND DISINTEGRATION
Resin-reinforced
ZOE (R-ZOE)
Eugenol ZnO, polymer,
resin
Acid-base
reaction
Crystalline zinc
eugenolate
5
Mechanical 48 Similar to ZOE Good initial sealing
and adequate
strength for nal
cementation of
restorations
LOW STRENGTH
Higher SOLUBILITY
AND DISINTEGRATION
EBA-modied ZOE
(ZOE-EBA)
Eugenol,
EBA
ZnO, Al
2
O
3
,
polymer
Acid-base
reaction
Crystalline zinc
eugenolate,
crystalline zinc
ethoxybenzoate
Mechanical 55 Similar to ZOE Long working time,
good ow and low
irritation to pulp
Hydrolytic
breakdown, plastic
deformation, poorer
retention
Zinc phosphate(ZP) H
3
PO
4
,
H
2
O
ZnO Acid-base
reaction
Crystalline tertiary
zinc phosphate
5.5
Mechanical 104 IRRITANT HIGH ELASTICITY PULP IRRITANT NO
BONDING NO ANTI-
CARIOGENICITY
Polycarboxylate(PC) PAA, H
2
O ZnO Acid-base
reaction
Amorphous zinc-
polyacrylate gel
6-9
Chemical 55 MILD (LARGE
MOLECULAR
SIZE)
CHEMICAL
BONDING
LESS PULP
IRRITANT
LESS WORKING TIME
Conventional GI (GI) PAA, H
2
O F-Al-Si glass Acid-base
reaction
Amorphous
aluminopolyacrylate
gel
7
Chemical 86 MILD FLUORIDE
RELEASE
CHEMICAL
BONDING
Initial slow setting
Moisture sensitive
Resin-modied GI
(RMGI)
PAA, H
2
O,
water-
soluble
monomers
F-Al-Si glass Light and
chemically
activated
polymerization
and acid-base
reaction
Amorphous
aluminopolyacrylate
gel, cross-linked
polymer
4
Chemical 170—200 Mild to
moderate
Control set, uoride
release, high exural
strength.
More microleakage
Compomer (CM) Monomers F-Al-Si glass Light-activated
polymerization
Amorphous cross-
linked polymer,
aluminopolyacrylate
gel
Command
set by light
activation
MICRO-
MECHANICAL
210—245 Moderate Fluoride release Cannot be used for
stress-bearing areas.
Composite (or resin)
(CP)
Monomers Silicate glass Light /
chemically
activated
poymerization
Amorphous cross-
linked polymer
Command
set by light
activation
MICRO-
MECHANICAL
200—350 Moderate MICRO-
MECHANICAL
BONDING
Polymerization
shrinkage Technique
sensitive
Preclinical Manual of conservative Dentistry anD enDoDontics
134
Clinical application Cement recommended
Base/liner for amalgam restorations:
Cavity with remaining dentin thickness greater than
0.5 mm
RMGIC
Zinc phosphate (low acid type)
Zinc polycarboxylate
Base/liner for amalgam restorations:
Cavity with remaining dentin thickness lesser than
0.5 mm or exposure
Calcium hydroxide liner followed by a base of either
RMGIC
or zinc polycarboxylate
or zinc phosphate (low acid type)
Base/liner for composite restoration:
Cavity with remaining dentin thickness greater than
0.5 mm
RMGIC / glass ionomer cement
Base/liner for composite restorations:
Cavity with remaining dentin thickness lesser than
0.5 mm or exposure
Calcium hydroxide liner followed by a base of
RMGIC / glass ionomer cement
Temporary lling material Zinc oxide eugenol
Intermediate lling material IRM (intermediate restorative material), EBA
Sealing of shallow cavity Copalite varnish
Deep caries management Calcium hydroxide followed by a temporary/
intermediate lling material
Direct/indirect pulp capping
Direct pulp capping
Calcium hydroxide followed by a temporary/
intermediate lling material
MTA or Biodentine
Temporary luting cement Zinc oxide eugenol polymer
Zinc polycarboxylate (thin mix)
Permanent luting cement Glass ionomer cement
Resin luting cement
Table 3.7 Selection of cements according to clinical application
A clinician has to thus select a restorative cement according to the given clinical
situation taking into consideration the principle application of each cement (Table 3.7).
Classication
BOX 3.7 Classification of amalgam
I. Based on copper content
• Conventional or low copper alloy
• High copper alloy
• High copper admixed alloy
• High copper unicompositional alloy
II. Based on amalgam alloy particle geometry
and size
• Lathe cut alloy
• Regular-cut
• Fine-cut
• Microne-cut
• Spherical alloy
• Admixed alloy
III. Based on zinc content
• Zinc containing alloy
• Zinc free alloy
IV. New amalgam alloys
Dental Materials anD tHeir ManiPulation
135
Constituents Low copper (%) Admixed (%) Unicompositional (%)
Silver 63270 69 40260
Tin 26229 17 22230
Copper 225 13 13230
Zinc 022 1
Table 3.8 Composition of alloy particles
Alloy
Mercury
Residual alloy
Mercury
reaction
products
Fig. 3.25 Setting reaction of amalgam
Setting Reaction (Fig. 3.25)
The general descriptive reaction is as follows, but varies according to the composition
of the amalgam alloy being used.
BOX 3.8 Phases of amalgam
Silver–tin phase
g
(Gamma)
Ag
3
Sn
Silver–mercury phase
g
1
(Gamma 1)
Ag
2
Hg
3
Tin–mercury phase
g
2
(Gamma 2)
Sn
7-8
Hg
Copper–tin phase
e
(Epsilon)
Cu
3
Sn
Copper–tin phase
h
(Eta)
Cu
6
Sn
5
Alloy particles for amalgam Dental amalgam
1 → 11
Mercury Non-reacted alloy powder particles
The various phases that are involved during the setting reaction of amalgam is provided
in Box 3.8.
V Gopikrishna
KNOW YOUR
OPERATING FIELD
CHAPTER
4
DENTAL CHAIR
• This clinical equipment comprises of an electrically operated and retractable patient
seating chair, to which compressed air, water line, micromotor, spittoon bowl, and an
overhead light is attached ( Fig. 4.1 ).
• It is also accompanied by a dental operator stool on which the clinician sits, while
handling the patient procedures.
Fig. 4.1 Dental operating chair
PHANTOM HEAD
• In the preclinical training area, instead of a dental chair, a phantom head is employed,
which simulates the environment present in the patient's oral cavity ( Fig. 4.2 ).
'The differences between a competent person and an incompetent person are
demonstrated in the knowledge of his surroundings'.
— Ron Hubbard
KNOW YOUR OPERATING FIELD
171
THREE-WAY SYRINGE
• Three-way syringe is a chairside metal syringe connected to an air–water line
( Fig. 4.10 ).
• It comprises of two buttons: One designated for water spray, while the other one
is for air spray.
• If both the buttons are pressed simultaneously, then the resultant spray is an air–
water spray.
• It is a useful device to cleanse the tooth preparation.
Water spray button
Air spray button
Three way syringe
Fig. 4.10 Three-way syringe
CAVITY HOLDER
• Cavity holder is an extension from the tray holder and would be in close proximity to
the operator ( Fig. 4.11 ).
• It would hold the following:
Either one/two air–water lines, to which airotor handpieces can be attached.
Three-way syringe.
Airmotor/micromotor base, to which the latch-type contra-angled or straight hand-
piece can be attached.
Speed control valve
for the airmotor/micromotor
Three-way
syringe
Airmotor/
micromotor base
Airotor water
spray regulator
Air-water line to
which an airotor
hardpiece is connected
Air-water line
Fig. 4.11 Cavity holder and its attachments
PRECLINICAL MANUAL OF CONSERVATIVE DENTISTRY AND ENDODONTICS
172
BEGINNERS' GUIDE FOR USING INSTRUMENTS AND EQUIPMENT
I. Connecting the Airotor Handpiece to the Air–Water Line
The air–water line is attached to the airotor handpiece with the help of coupling.
Step 1 n Appreciation of air–water line and airotor nozzle morphology ( Fig. 4.12 ).
Base of the
airotor handpiece
line coupling
Water line
Air-water
Air line
Water line nozzle
Air line nozzle
Fig. 4.12 Left: The air–water line consisting of a larger opening, which is the air line and one or two
smaller opening/s, which brings in the water line. Right: The connecting end of the airotor handpiece,
which has a larger nozzle for the air line and a smaller one to which the water line is connected
Airotor
handpiece
line coupling
Air-water
Fig. 4.13 Keep the air line and water line in alignment with the nozzles at the base of the airotor
handpiece. The coupling surrounding the top of the air–water line is then gently retracted
Step 2 n Retraction of air–water line coupling ( Fig. 4.13 )
Step 3 n Insertion of air–water line into the handpiece ( Fig. 4.14 )
FUNDAMENTALS OF TOOTH
PREPARATION AND PULP
PROTECTION
V Gopikrishna
CHAPTER
5
INTRODUCTION
Initially, the operator should assess the clinical condition of the tooth and formulate an
appropriate treatment plan. This involves the proper diagnosis and fi nalization of the
kind of restorative treatment in consultation with the patient's needs and aspirations.
The preparation of the tooth structure for a restoration varies according to the kind
of restorative material being chosen. However, there are certain core fundamental
principles that an operator has to follow immaterial of the kind of restoration. This
chapter would give an overview of the basic principles and nomenclatures involved dur-
ing tooth preparation.
Clinical Note
Earlier, preparation of tooth was referred to as cavity preparation, as a carious tooth is
usually cavitated. Currently, many indications for restorative treatment are not related
to carious destruction. Hence, the preparation of a tooth is referred to as tooth
preparation.
TOOTH PREPARATION
Defi nition
Tooth preparation is defi ned as the mechanical alteration of a defective, injured, or
diseased tooth such that placement of restorative material re-establishes normal form
and function, including aesthetic corrections, where indicated.
'Success is neither magical nor mysterious...
Success is the natural consequence of consistently applying the basic fundamentals'.
— Jim Rohn
PRECLINICAL MANUAL OF CONSERVATIVE DENTISTRY AND ENDODONTICS
200
I. Outline form and initial depth for pit and fi ssure lesions (Class I)
Factors that determine the outline form for pit and fi ssure lesions are as follows:
• The extent to which the enamel has been involved by the carious process.
• The extensions that must be made along the fi ssures to achieve sound and smooth
margins.
• The limited bur depth related to the tooth's original surface while extending the
preparation to sound external walls that have a pulpal depth of approximately
1.5−2 mm and maximum depth into dentin of 0.2 mm ( Fig. 5.15
).
701
0.75 mm
0.5 mm
DEJ
0.2 mm
(a)
CEJ
DEJ
0.2 mm
(b)
Fig. 5.15 Initial tooth preparation. Note in (a) and (b) that extensions in all directions are to sound tooth
structure while maintaining a specifi c limited pulpal or axial depth regardless whether end (or side) of
bur is in dentin, caries, old restorative material, or air. DEJ and CEJ indicated in (b). Note in (a) that
initial depth is approximately two-thirds of 3 mm bur head length, or 2 mm, as related to prepared
facial and lingual walls, but is half the No. 245 bur head length, or 1.5 mm, as related to central fi ssure
location
Clinical Note
The preparation is placed in dentin for the following reasons:
i. To avoid seating the restoration on the very sensitive DEJ, where maximum intercon-
nection of dentinal tubules exist.
ii. To give bulk for the restorative material.
iii. To allow the restoration to take advantage of the dentin's elasticity during insertion
and function.
FUNDAMENT ALS OF TOOTH PREPARATION AND PULP PROTECTION
201
OK
½ to – Consider capping
3
2
or more–recommend capping
2
3
½
Primary groove
Cusp tip
Central
groove
Mandibular molar
Facial groove
2
3
½
Primary
groove
Fig. 5.16 Rule for cusp capping: If extension from a primary groove toward the cusp tip is no more than
half the distance, then no cusp capping; if this extension is from one-half to two-thirds of the distance, then
consider cusp capping; if the extension is more than two-thirds of the distance, then usually cap the cusp
Rules
• Rule 1 n Extend the tooth preparation margin, until sound tooth structure is ob-
tained and no unsupported or weakened enamel remains.
• Rule 2
n Avoid terminating the margins on extreme eminences, such as cusp height
or ridge crests.
• Rule 3
n If the extension from a primary groove includes one-half or more of the
cuspal incline, then consideration should be given to capping the cusp. If the exten-
sion is two-thirds, then cusp capping should be done ( Fig. 5.16 ).
Fig. 5.17 Extension into the fi ssures during initial placement of outline form
• Rule 4 n Extend the preparation margin to include the entire fi ssure that cannot be
eliminated by appropriate enameloplasty ( Fig. 5.17 ).
PRECLINICAL MANUAL OF CONSERVATIVE DENTISTRY AND ENDODONTICS
208
Fig. 5.27 Box/inverted truncated shape cavity preparation for achieving primary resistance form
Clinical Note
i. Minimally extended faciolingual walls conserve dentin, supporting the cusps and fa-
ciolingual ridges, maintaining as much strength of the remaining tooth structure as
possible. This resistance is against the obliquely delivered forces and the forces in
the tooth's long axis.
II. Second principle of minimal faciolingual extension
The faciolingual extension of the external walls is restricted to allow strong cusp and
ridge areas to remain with suffi cient dentin support.
Clinical Note
The relatively horizontal pulpal and gingival fl oors prepared perpendicular to the
tooth's long axis help resist forces in the long axis of the tooth and prevent tooth
fracture from wedging effects caused by opposing cusps.
(a) (b)
Fig. 5.28 Resistance forms must consider resistance of tooth to fracture from forces exerted on restoration.
Flat fl oor (a) will help prevent restoration movement, whereas a too rounded pulpal fl oor (b) may allow
a nonbonded restoration rocking action producing a wedging force, which may result in shearing of
tooth structure
FUNDAMENT ALS OF TOOTH PREPARATION AND PULP PROTECTION
209
IV. Fourth principle of cusp capping
Reducing and covering (capping) weak cusps, and enveloping or including enough of a
weakened tooth within the restoration in extensive tooth preparations to prevent or resist
fracture of the tooth by forces in the long axis and obliquely (laterally) directed forces.
Clinical Note
i. A tooth weakened by extensive caries deserves consideration of the fourth principle
( reducing and capping weakened cusps or extending to include cusps entirely ) in ob-
taining the primary resistance form during tooth preparation.
ii. The basic two rules that guide the reduction of cusps during initial tooth preparation:
•
Cusp reduction should be considered when the outline form has extended half the
distance from a primary groove to a cusp tip, and
•
Cusp reduction usually is strongly recommended when the outline form has extend-
ed two-thirds the distance from a primary groove to a cusp tip.
(a)
(b)
Fig. 5.29 Rounding or coving of internal line angles to minimize stress concentrations
ii. Vale experiment had proved that the tooth's resistance to fracture decreases
signifi cantly when:
•
Marginal ridges are involved
•
Intercuspal distance is increased
III. Third principle of rounded line angles
Slight rounding of internal line angles to reduce stress concentrations in tooth structure
( Fig. 5.29
).
Clinical Note
Internal and external angles within the tooth preparation are slightly rounded, so that
stresses in the tooth and restoration from masticatory forces are not as concentrated
at these line angles. Rounding of internal line angles reduces the stress on the tooth,
and resistance to fracture of the tooth is increased.
G Vijayalakshmi, and V Gopikrishna
PRECLINICAL PLASTER
MODEL EXERCISES
CHAPTER
6
INTRODUCTION
Plaster model exercise deals with preparation of tooth from class I to class V in
plaster models of different teeth, which are three times the size of the natural teeth.
Tooth are prepared with the help of an enamel chisel and the tooth dimensions are
measured with a graduated probe (Williams probe).
These exercises are meant to make the student:
i. Appreciate the tooth morphology better.
ii. Understand the nomenclature of the tooth walls and surfaces.
iii. Understand the basic principles of tooth preparation including outline, resistance,
retention, and convenience forms.
CLASS I TOOTH PREPARATION: WALLS, LINE ANGLES, AND POINT
ANGLES
Exercise I: Class I in Maxillary First Premolar ( Figs 6.1⫺6.14 )
Dimensions
• Width of the tooth: 2.5 mm at the centre and 3 mm at the dovetail region
• Depth of the tooth: 4⫺5 mm
"A person who never made a mistake never tried anything new."
— Albert Einstein
PRECLINICAL PLASTER MODEL EXERCISES
241
Fig. 6.78 Occlusal anatomy
Fig. 6.79 Central pit
Fig. 6.80 Central fi ssure
Fig. 6.81 Outline form
Fig. 6.82 Outline involving the buccal and lingual
grooves
Fig. 6.83 Outline showing dovetail in mesial margin
PRECLINICAL MANUAL OF CONSERVATIVE DENTISTRY AND ENDODONTICS
242
Fig. 6.85 Punch cut in the central pit
Fig. 6.86 Measuring the depth of the punch cut
with a graduated probe
Fig. 6.87 Tooth extended using a chisel
Fig. 6.88 Tooth extended mesiodistally
Fig. 6.89 Measuring the depth of the tooth
Fig. 6.84 Circumventing along the cusp
PRECLINICAL PLASTER MODEL EXERCISES
243
Fig.6.90 Tooth extended into buccal and lingual
grooves for prevention of further caries formation
Fig. 6.91 Giving an inverted truncated shape to
the tooth
Fig. 6.92 Undercut formed at pulpal line angles
Fig. 6.93 Dovetail, a retentive feature at proximal
margins
Fig. 6.94 Pulpal fl oor checked for fl at smooth
surface for providing resistance feature
Fig. 6.95 Sharp margins and line angles rounded
PRECLINICAL MANUAL OF CONSERVATIVE DENTISTRY AND ENDODONTICS
244
Fig. 6.96 Cavosurface margin at 90 degrees
known as butt joint
Fig. 6.97 Measuring the fi nal depth of the tooth
Fig. 6.98 Completed tooth preparation
Exercise VII: Class I Tooth with Buccal Extension in Mandibular
First Molar ( Figs 6.99⫺6.127 )
Dimensions
• Width of the tooth
3 mm (measuring till the groove and near the dovetail region)
2 mm between the cusps
• Depth of the tooth: 4⫺5 mm
• Mesiodistal extension of the tooth: 10⫺12 mm
• Width of the buccal extension: 1.5⫺2 mm
• Depth/height of the axial wall: 3 mm
• Width of the gingival seat (mesiodistal): 2.5 mm
• Depth of the gingival seat (buccolingual): 2.5⫺3 mm
PRECLINICAL PLASTER MODEL EXERCISES
269
Fig. 6.223 Buccoproximal wall
Fig. 6.224 Buccoproximal fl are on the distal side
Fig. 6.225 Linguoproximal fl are
Fig. 6.226 Measuring the proximal (distal) ditch cut
Fig. 6.227 Measuring the width of the tooth near
the central fi ssure
Fig. 6.228 Completed MOD tooth—occlusal view
PRECLINICAL PLASTER MODEL EXERCISES
277
Fig. 6.264 Measuring the axial wall depth pala-
tolabially
Fig. 6.265 Probe pointing to the axiolabial line
angle. Measuring the mesiodistal extension
Fig. 6.266 Axiolabioincisal point angle
Fig. 6.267 Probe pointing to the axiolabiogingi-
val point angle in the gingival seat
Fig. 6.268 Completed tooth preparation—palatal
view
Fig. 6.269 Completed tooth preparation—
proximal view
'I've missed over 9,000 shots in my career. I've lost almost 300 games. 26 times I've been
trusted to take the game-winning shot . . . and I've missed, I've failed over and over and
over again in my life. And that is why I succeed'.
— Michael Jordan
V Gopikrishna and G Vijayalakshmi
PRECLINICAL TYPODONT
EXERCISES
CHAPTER
7
PRECLINICAL EXERCISES
• Class I tooth preparation for amalgam restoration
Mandibular fi rst molar
Mandibular fi rst premolar
Maxillary fi rst molar
Mandibular fi rst molar with buccal extension
• Class II tooth preparation for amalgam restoration
MO—mesio-occlusal tooth in mandibular fi rst molar
Box only MO—mesio-occlusal tooth in mandibular fi rst molar
Conservative MO—mesio-occlusal tooth in mandibular fi rst molar
DO—disto-occlusal tooth in maxillary fi rst molar
MO—mesio-occlusal tooth in mandibular fi rst premolar for composite restoration
DO—disto-occlusal tooth in mandibular fi rst premolar
MOD—mesio-occluso-distal tooth in mandibular fi rst molar
• Class III tooth preparation for glass ionomer restoration
• Incisal build up (Class IV) of maxillary central incisor for composite restoration
• Class V tooth preparation for glass ionomer restoration in mandibular fi rst molar
• Cast metal inlay tooth preparation, fabrication of wax pattern, and casting technique
in a mandibular second molar
CLASS I TOOTH PREPARATION FOR AMALGAM RESTORATION
Defi nition of Class I
Tooth preparation in one or more of the following locations:
a. Pits and fi ssures of occlusal surfaces of molars and premolars.
PRECLINICAL MANUAL OF CONSERVATIVE DENTISTRY AND ENDODONTICS
320
Fig. 7.89 Occlusal preparation extended mesi-
ally without breaking the proximal enamel wall
Dovetail
Reverse curve
Fig. 7.90 Dovetail given on the uninvolved proxi-
mal side. Reverse curve and proximal fl are given
on the mesial side
Fig. 7.91 Bur placed extracoronally to ascertain
the proposed depth of the proximal box
Fig. 7.88 Occlusal preparation completed
PRECLINICAL TYPODONT EXERCISES
321
Fig. 7.92 Proximal ditch cut prepared with an in-
tact margin after placement of matrix band to pre-
vent the inadvertent nicking of the adjacent tooth
Fig. 7.93 Refi ning the axial wall and the gingival
seat
(a)
(b)
Fig. 7.94 (a, b) Removal of the thin shell of enamel wall with a chisel or hatchet
PRECLINICAL MANUAL OF CONSERVATIVE DENTISTRY AND ENDODONTICS
322
Fig. 7.97 Cleaving the marginal enamel and planing the walls with a hatchet
(a) (b)
Fig. 7.96 (a, b) Gingival marginal trimmer used to rounden the axiopulpal line angle
Fig. 7.95 Contact broken in all three planes—facially, lingually, and gingivally
PRECLINICAL TYPODONT EXERCISES
323
Fig. 7.98 Planing the gingival fl oor to render it
smooth and free from irregularities with a hatchet
Fig. 7.99 Using a gingival marginal trimmer to
plane the gingival seat margin
Fig. 7.100 The round end of the plastic instru-
ment is moved along the pulpal fl oor in order to
check the convenience form
Fig. 7.101 Completed Class II mesio-occlusal
tooth preparation
PRECLINICAL TYPODONT EXERCISES
337
Fig. 7.142 Amalgam restoration after completion of the polishing procedure
Exercise VI n Class II Box Only Tooth Preparation MO (Mesio-Occlusal) in a
Mandibular First Molar ( Figs 7.1437.147 )
Fig. 7.144 Punch cut on the involved marginal
ridge without breaking the proximal wall
Fig. 7.143 Outline form
Fig. 7.145 Initial tooth preparation without breaking the contact
V Gopikrishna
INTRODUCTION TO
PRECLINICAL ENDODONTICS
CHAPTER
8
ENDODONTICS
Endodontics is the branch of dentistry that deals with diagnosis, treatment, and
prevention of pulpal and periradicular diseases. It includes preservation of vitality of
the tooth, treatment of a diseased pulp, and restoration of the tooth to its form and
function.
PULP CAVITY
The pulp cavity is the central cavity within a tooth and is entirely enclosed by dentin,
except at the apical foramen (Fig. 8.1). The pulp cavity may be divided into:
• A coronal portion n Pulp chamber
• A radicular portion n Root canal
PULP CHAMBER
In anterior teeth, the pulp chamber gradually merges into the root canal and this divi-
sion becomes indistinct. In multirooted teeth, the pulp cavity consists of a single pulp
chamber and usually three root canals, although the number of canals can vary from
one to four or more.
• Roof of the pulp chamber consists of dentin covering the pulp chamber occlusally or
incisally (Fig. 8.1).
• A pulp horn is an accentuation of the roof of the pulp chamber directly under a cusp
or developmental lobe. The term refers more commonly to the prolongation of the
pulp itself directly under a cusp.
'Never must the physician say the disease is incurable. By that admission he denies God,
our Creator; He doubts Nature with her profuseness of hidden powers and mysteries'.
— Paracelsus
Preclinical Manual of conservative Dentistry anD enDoDontics
390
Fig. 8.2 Microcomputed tomographic three-dimensional models of the most common root canal config-
uration in all groups of teeth. In most of the teeth, the common root canal morphology is the presence of
one canal per root with the exception of the mandibular incisors, the maxillary premolars, the mesiobuc-
cal root of maxillary first molar, and the mesial root of mandibular molars, which used to have two root
canals. B: buccal; P: palatal; MB: mesiobuccal; DB: distobuccal; M: mesial; D: distal (Courtesy: Marco
Versiani, PÈcora and Sousa-Neto, Brazil; Adapted from Suresh Chandra and Gopikrishna: Grossman's
Endodontic Practice 13th ed; Wolters Kluwer)
introDuction to Preclinical enDoDontics
391
TREATMENT PROCEDURES IN ENDODONTICS
I. Vital Pulp Therapy
Denition
Vital pulp therapy is the treatment initiated on an exposed pulp to repair and maintain
the pulp vitality. The aim of vital pulp therapy is to treat reversible pulpal injuries in
order to maintain pulp vitality in both primary and permanent teeth. It includes two
distinct therapeutic approaches:
1. Indirect pulp capping: Advocated in cases of deep carious lesions.
2. Direct pulp capping or pulpotomy: Advocated in cases of pulp exposure.
Clinical Note
The clinical decision to choose between direct versus indirect pulp capping would be
based on the clinician's ability to clinically distinguish between infected and affected
dentin (Table 8.1).
A. Indirect pulp capping
Denition
Indirect pulp capping is dened as a procedure wherein the deepest layer of the
remaining affected carious dentin is covered with a layer of biocompatible material
in order to prevent pulpal exposure and further trauma to the pulp (Fig. 8.3).
B. Direct pulp capping
Denition
Direct pulp capping is dened as a procedure in which the exposed vital pulp is covered
with a protective dressing or base placed directly over the site of exposure in an
attempt to preserve pulpal vitality (Box 8.1).
Table 8.1 Differences between infected and affected dentin
Sl. No. Infected dentin Affected dentin
1 Soft and demineralized dentin teaming with
bacteria
Demineralized dentin, not yet invaded by
bacteria
2 Collagen is irreversibly denatured Collagen cross-linking remains
3 Cannot remineralize Can act as template for remineralization, if
appropriate biocompatible material is placed
over it
4 Soft necrotic tissue followed by dry leathery
dentin which flakes away with an instrument
Discoloured and softer than normal dentin that
does not flake easily
5 Dyes: 1% acid red in propylene glycol stains
only irreversibly denatured collagen
Does not stain with the caries-detecting dye
introDuction to Preclinical enDoDontics
393
III. Apexication
Denition
Apexication is dened as a method to induce a calcic barrier across an open apex
of an immature pulpless tooth.
BOX 8.1 Clinical decision chart between direct and indirect pulp capping
Deep Carious Lesion
Anesthesia and rubber dam isolation
Removal of Caries,
A. Infected dentin removed with a round bur (#6 or #8)
in a slow speed handpiece
B. Peripheral carious dentin removed with spoon
shaped excavator(31 and 33 L)
No pulpal Exposure
Pulpal Exposure
Affected dentin is covered with
hard set Ca(OH)
2
and an overlying
base of IRM
Wait for 6-8 weeks
Patient asymptomatic
Anesthesia and rubber dam isolation
Temporary filling material is
removed carefully
Clinically confirm the change in colour and
hardness of affected dentin
Hard set Ca(OH)
2
is placed followed by an RMGIC
liner and a bonded composite restoration
2nd appointment
Direct Pulp Capping/
Cvek Pulpotomy/ Full Pulpotomy
Clinical Note
Apexication differs from apexogenesis, which is dened as the physiological process of
root development in a tooth.
introDuction to Preclinical enDoDontics
405
BOX 8.2 Flowchart for Ingle's radiographic method of working length determination. (Adapted
from Suresh Chandra and Gopikrishna: Grossman's Endodontic Practice 13th
ed; Wolters Kluwer)
Diagnostic radiograph used to estimate the working length of tooth by measuring
the tooth from a stable occlusal reference point till the radiographic apex
Subtract atleast 1 mm from this length as
This measurement is transferred to a diagnostic instrument with a silicon stop,
which is placed in the root canal and working length radiograph taken
On the radiograph, measure the difference between the end of the instrument
and the radiographic apex of the root
Tip of the instrument ends 0.5 mm–1.0 mm from the radiographic
root apex (Working length established)
Short of the radiographic apex
by more than 1.0 mm
Beyond the radiographic apex
Reduce this value from the earlier
estimated length and adjust stopper
on the diagnostic instrument accordingly
Add this value to the earlier estimated
length and adjust stopper on the
diagnostic instrument accordingly
Retake the working length radiograph Retake the working length radiograph
■
Minor constriction is always present short of the anatomic apex
■
Compensation for radiographic image distortion
G Vijayalakshmi, E Sivapriya, and V Gopikrishna
COMMON VIVA QUESTIONS
AND SPOTTERS
CHAPTER
9
'He who asks a question is a fool for fi ve minutes,
He who does not ask a question remains a fool forever'.
— Chinese Proverb
COMMONLY ASKED VIVA QUESTIONS
Defi ne operative dentistry.
According to Sturdevant, 'Operative dentistry' is the art and science of diagnosis,
treatment, and prognosis of teeth that do not require full coverage restoration for cor-
rection. Such treatment should result in the restoration of proper tooth form, function,
and aesthetics, while maintaining the physiological integrity of the teeth in harmonious
relationship with the adjacent hard and soft tissues, all of which should enhance the
general health and welfare of the patient.
Defi ne tooth preparation.
Tooth preparation is defi ned as the mechanical alteration of a defective, injured, or
diseased tooth, such that placement of restorative material will re-establish normal
form and function, including aesthetic corrections where indicated.
What are the types of tooth preparation?
• Conventional: A preparation where apart from removal of diseased portion, exten-
sion is also made so as to include all pits and fi ssures and unsupported areas to
prevent further caries formation for a specifi c restoration, e.g. amalgam, direct fi lling
gold, and cast restoration.
• Conservative: It is a preparation where tooth structure is removed as much as need-
ed for a given restoration, without extending for prevention of further decay, e.g.
slot, box only, tunnel, occlusal pits, composite restoration, and glass ionomer
restorations where only diseased portion is removed.
PRECLINICAL MANUAL OF CONSERVATIVE DENTISTRY AND ENDODONTICS
408
Currently, between conventional tooth preparation and conservative tooth
preparations which one is recommended?
Conventional tooth preparations are taught during conservative pre-clinical laboratory
training to enable a student to improve his/her tactile skills.
In clinical practice, preservation of tooth structure is of paramount importance. Hence,
conservative tooth preparation is the design of choice that is clinically recommended.
Who is the father of modern operative dentistry?
Dr GV Black.
Defi ne class i tooth preparation.
Tooth preparations involving the pits and fi ssures of the premolars and molars and
on the occlusal two-thirds of the facial and lingual surfaces of premolars and molars.
It also includes preparations on the lingual surface of the maxillary incisors.
Defi ne class ii tooth preparation.
Tooth preparations involving the proximal surface (mesial and distal) of the posteriors.
Defi ne class iii tooth preparation.
Tooth preparations involving the proximal surfaces of the anteriors that do not involve
the incisal edge.
Defi ne class iv tooth preparation.
Tooth preparations involving the proximal surfaces of the anteriors that involve the
incisal edge.
Defi ne class v tooth preparation.
Tooth preparations involving the gingival third of the facial, lingual, or palatal surfaces
of all teeth.
Defi ne class vi tooth preparation.
Tooth preparations involving the incisal edge and the cuspal heights of the posteriors.
Why should the pulpal fl oor not be placed at DEJ and should be placed in
sound dentin for silver amalgam tooth preparations?
Pulpal fl oor should not be placed at DEJ, as the possibility of hypersensitivity increases.
The reason for this is attributed to the branching of dentinal tubules and the cytoplasmic
processes into two, resulting in more number of dentinal tubules at DEJ.
The advantage of placing the preparation fl oor on to the dentin is the resilience of
dentin aids in the retention form of the amalgam restoration. The relatively increased
COMMON VIVA QUESTIONS AND SPOTTERS
409
depth of preparation into the dentin would also improve the resistance form of the
amalgam restoration.
How to differentiate between dentin and enamel during tooth preparation?
• Dentin is yellower than enamel.
• Dentin is opaque and dull compared to enamel, while enamel is shiny and refl ects
light better (highly translucent).
• There will be a metallic sound when a probe is passed over enamel, whereas it is
smooth in dentin.
• Clinically, the patient could experience hypersensitivity when a probe is passed over
dentin.
What is height of contour?
The area of greatest circumference on the facial and lingual surfaces of the tooth is
called 'height of contour'. In the posterior teeth, the height of contour is located in the
gingival third of the facial surface and in the middle one-third of the lingual surface.
What is proximal contour area?
Proximal contact area denotes the area of proximal height of contour of the mesial or
distal surface of a tooth that touches (contacts) it's adjacent tooth in the same arch.
What are internal and external walls?
• Internal wall: An internal wall is a prepared surface that does not extend to the
external tooth surface.
• External wall: External wall is a prepared surface that extends to the external tooth
surface.
What are enamel wall and dentinal wall?
The enamel wall is that portion of a prepared external wall consisting of enamel.
The dentinal wall is that portion of a prepared external wall consisting of dentin in
which mechanical retention features may be located.
What is cavosurface angle?
It is the angle of the tooth structure formed by the junction of a prepared cavity wall
and the external tooth surface.
What is the cavosurface angle for an amalgam tooth preparation?
Cavosurface angle for an amalgam tooth preparation is 90°.
What is the cavosurface angle for an inlay tooth preparation?
Cavosurface angle for an inlay tooth preparation is 135145°.
PRECLINICAL MANUAL OF CONSERVATIVE DENTISTRY AND ENDODONTICS
420
What are the dimensions and design of 245 tungsten carbide bur?
No. 245 Tungsten Carbide bur has a head length of 3 mm and a tip diameter of 0.8 mm.
The sides of the bur is slightly convergent towards the shank and slightly rounded at the
corners of the end.
What are the important hand instruments used for amalgam and inlay
cavity preparations?
Design Formula
Use and mode
of action
Spoon
excavators
Double-ended instrument.
One blade is curved to
right and another to left.
Cutting edge along the
periphery of the circular
blade
15-7-14 Scooping action
Hoe
Cutting edge
is perpendicular to the long
axis of the instrument
4½-1½-22 Used to remove
unsupported enamel
rods and undermined
enamel. Distally
bevellled hoe is useful
in medial wall and
mesially bevelled hoe
for the distal wall.
Downward cutting
motion or push or
pull for smoothening
fl oors
Enamel
hatchet
Paired instrument with a
right and left instrument.
Cutting edge is parallel to
the long axis of the shaft.
Straight blade and is a
single plane instrument.
Three- numbered
instrument.
10-7-14 Remove unsupported
enamel rods and
undermined enamel.
Push motion.
GMT
(Gingival
Marginal
Trimmer)
Paired double-ended
instrument. Curved blade.
Cutting edge is not at right
angle to the blade and
hence has a four number
formula.
12½-90-7-14 and
12½-85-7-14 are the
distal and medial
pairs for amalgam
preparations.
12½-100-7-14 and
12½-75-7-14 are the
distal and medial
pairs for inlay
preparations.
Bevelling or trimming
unsupported enamel
margins of the gingival
seat and rounding of
axiopulpal line angle.
Lateral scraping
motion.
M Abarajithan and V Gopikrishna
GLOSSARY OF TERMS
CHAPTER
10
Operative dentistry is the art and science of the diagnosis, treatment, and prognosis
of defects of teeth that do not require full coverage restorations for correction. Such
treatment should result in the restoration of proper tooth form, function, and aesthet-
ics, while maintaining the physiological integrity of the teeth in harmonious relationship
with the adjacent hard and soft tissues, all of which should enhance the general health
and welfare of the patient.
ANATOMICAL LANDMARKS
Crown: It is the part of a tooth that is covered with enamel or an artifi cial substitute
for that part.
Neck: It is the slightly constricted part of a tooth between the crown and the root.
Root: The part of the tooth below the neck covered by cementum and attached by the
periodontal ligament to the alveolar bone.
Dentinoenamel junction (DEJ): The dentinoenamel junction (DEJ) is the junction of the
enamel and dentin.
Cementoenamel junction (CEJ): The cementoenamel junction (CEJ) is the junction of
the enamel and cementum.
Anatomic tooth crown: The anatomic tooth crown is the portion of the tooth covered
by enamel.
Clinical tooth crown: The clinical tooth crown is the portion of the tooth crown, which
is exposed to the oral cavity.
Cusp: A cusp is an elevation or mound on the crown portion of a tooth making up a
divisional part of the occlusal surface.
'A rose is a rose is a rose'.
— Gertude Stein
PRECLINICAL MANUAL OF CONSERVATIVE DENTISTRY AND ENDODONTICS
452
Cingulum: A cingulum is the lingual lobe of an anterior tooth and makes up the bulk of
the cervical third of the lingual surface.
Ridge: A ridge is any linear elevation on the surface of a tooth and is named according
to its location (e.g. buccal, incisal, or marginal ridge).
Triangular ridge: Triangular ridges descend from the tips of the cusps of molars and
premolars towards the central part of the occlusal surface.
Oblique ridge: Oblique ridge is a ridge obliquely crossing the occlusal surfaces of maxillary
molars connecting the distobuccal cusp and the mesiopalatal cusp.
Fossa: A fossa is an irregular depression or concavity. Central fossa is seen on the occlusal
surface of molars.
Developmental groove: Developmental groove is a shallow groove or line between the
primary parts of the crown or root. Sound coalescence of the lobes results in grooves;
faulty coalescence results in fi ssures.
Pits: Pits are small pinpoint depressions located at the junction of developmental
grooves or at terminals of those grooves.
Embrasures (spillways): When two teeth in the same arch are in contact, their curva-
tures adjacent to the contact areas form spillway spaces are called embrasures.
Contact area: It is the area in which the two proximal surfaces of adjacent teeth come
into contact.
Intercuspal distance: It is the distance between two cusp tips.
Occlusion: It is the interrelationship between the incising and occlusal surfaces of the
maxillary and mandibular teeth.
Enamel: It is a mineralized tissue that forms a protective covering of variable thick-
ness over the entire surface of the crown of the tooth. It is the hardest tissue in the
human body that provides a resistant covering suitable for mastication. Its composition is
approximately 96% inorganic and 4% organic substance and water.
Ameloblasts: Ameloblasts are cells that help in formation of enamel. They originate
from the embryonic germ layer, ectoderm.
Enamel rods: Enamel is composed of enamel rods or prisms which run from the dentino-
enamel junction to the surface through the structure of enamel. Enamel rods are always
perpendicular to the DEJ and external enamel surface.
Gnarled enamel: Enamel rods at the cuspal and incisal regions appear intertwined,
twisted, and are more irregular. Gnarled enamel aids in resisting the high masticatory
loads without fracture.
Dentin: Dentin is a mineralized tissue that forms the bulk of the crown and root of the
tooth, giving the root its characteristic form; surrounds coronal and radicular pulp,
forming the walls of the pulp chamber and root canals; composition is approximately
67% inorganic, 20% organic, and 13% water.
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