2. Introduction
The main challenges for
centuries have been the
development and selection of
biocompatible, long-lasting
,direct-filling tooth restoratives
materials that can withstand the
adverse conditions of the oral
environment .
3. Introduction
Restorative dental materials consist of all
synthetic components that can be used to repair or
replace tooth structure, including bonding agents,
liners, cement bases, amalgams , composites,
compomers, hybrid ionomers, cast metals, and
ceramics .
4. Ideal restorative material would be :
1. biocompatible .
2. bond permanently to tooth structure.
3. match the natural appearance of tooth structure.
4. exhibit properties similar to those of tooth enamel, dentin .
5. capable of initiating tissue repair or regeneration of missing or
damaged tissues.
6. 1) AMALGAM
Dental amalgam is produced by mixing liquid
mercury with solid particles of an alloy
containing predominantly silver, tin, and
copper.
is used most commonly for posterior
restorations and for cores .
7. AMALGAM
Disadvantages
Advantages
1. silver color does not match
tooth structure.
2. somewhat Brittle.
3. Are subject to corrosion and
galvanic action.
4. Do not help retain weakened
tooth structure.
1. easy to insert .
2. are not technique sensitive.
3. have adequate resistance to fracture
4. prevent marginal leakage
5. can be used in stress-bearing areas .
6. have long service life .
7. cost effective .
9. Varnish
used as a liner for cavity preparations.
inhibits surface bounding of composite resin system.
Prevents fluoride release from Glass ionomer .
When used with amalgam :
reduces micro- leakage at restoration margins,
inhibits penetration of corrosion products into dentine .
does not prevent thermal sensitivity .
10. 2)resin based Composite:
Disadvantages
Advantages:
Dimensional unstable.
should be placed in dry field.
Instable in water.
Esthetic
rapidly set
strong
it is hardness similar to dentine.
low thermal conductivity
11. Classification of Composite
1. Macrofilled composites
2. Microfilled Composites
3. Small-particle And Hybrid Composites
1. Chemical Curing.
2. Light Curing.
12. Method of manipulation of composite resin
3) Washing
2) Acid-etching.
1) Cavity preparation
6) composite resin placed
5) Resin-bonding agent
4) Dried for at least 15 sec.
13. 3) Glass ionomer
introduced by Wilson & Kent in 1972.
Material was based on reaction between silicate glass
powder & polyacrylic acid.
They bond chemically to tooth structure & release
fluoride for relatively long period.
Note : Initial release is high. But declines after 3
3 months. After this, fluoride release continuous for a
for a long period.
14. CLASSIFICATION OF GI
For luting
For restoration
Type I
Type II.1 Restorative esthetic
Type II.2 Restorative reinforced
Type II
For liner & bases
Type III
Fissure sealent
Type IV
As Orthodontic cement
Type V
For core build up
Type IV
‘self-cured’
OR
‘light-cured’
15. ADVANTAGES AND DISADVANTAGES OF GI
Disadvantages
Advantages
1) Low fracture and wear resistance.
2) Low resistance.
3) Water sensitive.
4) Less esthetic .
5) Potential for discolouration &
staining.
6) The complete setting reaction takes
place in 24 hrs, cement should be
protected from saliva during this
period
1) Anticariogenic property (Release F-).
2) Biocompatibilty .
3) bonds chemically to the tooth structure (Bonding
with enamel is higher than that of dentin ).
4) Better mechanical properties.
5) Inherent adhesion to the tooth surface
6) Good marginal seal.
7) Thermal expansion similar to that of tooth
structure
8) Minimal cavity preparation required.
9) is tooth coloured material & available in different
shades
16. USES OF GLASS IONOMER
1. Class I, II, III and V restorations in primary teeth.
2. Class III and V restorations in permanent teeh.
3. Caries control with:
A. high risk patients.
B. ITR.
C. ART.
4. For luting.
5. Cavity base and liner.
6. For core build up.
7. As an orthodontic bracket adhesive.
17. MODIFICATIONS OF GI
1. Water settable glass ionomer cement
2. Resin modified glass ionomer cement
3. Metal modified glass ionomer cement (Cermet)
4. Compomer
18. Method of manipulation of G I :-
Mix powder & liquid
on paper or glass slab
by metal spatula.
Should be pleased on
dry field.
19. 4.Compomer
• They were introduced in the early 1990s as a hybrid
of two other dental materials: dental composites and
glass ionomer cement.
• Setting reaction is light activated ( cured by light in
increments of 2 to 2.5 mm ).
• Adhesive system is based on acid etch found with all
composite resin.
• used for restorations in low stress–bearing areas.
20. 4.Compomer
• Recent product is recommended for class 1 and
class 2 restorations .
• Recommended for patients at medium risk of
developing caries .
• packaged in unit-dose compules and syringes.
• They require a bonding agent to bond to tooth
structure.
• compomers release less fluoride than do
conventional and hybrid GICs.
21. Other restorative materials
1) Zinc oxide eugenol
(Zinc oxide powder) + (eugenol liquid)
• ZOE modifications
• because of the low compressive strength of ZOE
added named intermediate restorative material
(IRM) & increasing the setting time limits the
properties of the eugenol.
21
22. 1) Zinc Oxide-Eugenol
uses
Type
is used for temporary cementation,
Type I
is intended for long-term cementation of fixed prostheses
Type II
is used for temporary fillings and thermal insulating bases,
Type III
whereas Type 1V cement is indicated for intermediate restorations.
Type IV
Varieties of ZOE cements also serve as root canal material in primary
teeth and periodontal dressings
23. 1) Zinc Oxide-Eugenol
Disadvantages
Advantages
• cause inflammation&necrosis if directly placed to pulp.
• hydrolyze in oral fluids.
• may cause internal resorption
anti microbial properties.
anti inflammatory properties..
non toxic.
ability to relief pain .
Stimulates reparative dentin when
used in indirect pulp capping.
24. 2) Calcium hydroxide
Calcium hydroxide cements are supplied in :
visible light-cured system.
two-paste system.
The alkaline pH aids in preventing bacterial
invasion.
base paste containing
A catalyst paste containing :
1) calcium tungstate.
2) calcium phosphate.
3) zinc oxide in glycol salicylate to
form an amorphous calcium
disalicylate.
1) calcium hydroxide.
2) zinc oxide.
3) zinc stearate in ethylene toluene.
4) Sulfonamide.
26. Introduction
Isolation from cheeks & tongue is necessary to
permit good access & clear view of , the teeth .
isolation from saliva is important because moisture
affects the setting reactions & the physical properties
of amalgam & other restorative materials
28. 4.Rubber dam
advantages :
1) Better access & visualization are gained by retracting
soft tissues .
2) providing dark contrasting background to the teeth .
3) Moisture control is superior to other forms of
isolation .
4) by preventing aspiration or swallowing of foreign
bodies & by protecting soft tissues .
5) decreased operating time.
6) Many children tend to become more quiet & relaxed
with rubber dam in place
29. Contraindications of Rubber Dam
1. The presence of fixed orthodontic appliances .
2. A very recently erupted tooth.
3. Child with an upper respiratory tract infection ,
congested nasal passages ,or other nasal
4. Patient allergy to latex.
5. Severe gingival inflammation .
Note : small (2_3cm) hole is cut in the dam this allow
for some mouth breathing children .
30. Armamentarium of Rubber
Dam
Clamp.
A Rubber Dam Punch
5 X 5 Inch Sheets of
Medium Latex,
Clamp Forceps
Rubber Dam Frame.
Plastic Frame Metal Frame
32. Common rubber dam clamps for pediatric restorative
dentistry
• Partially erupted permanent molars : 14A, 8A ( ivory )
clamps have jaws angled gingivally to seat below subgingival height of
contour .
• Fully erupted permanent molars: 14A , 8 Ivory .
• Second primary molars : 26 , 27 ( sswhite ) , w2A ( hygenic ) .
• First primary molars, premolars & canine: 2A Ivory , 27 ( sswhite ).
33. Placement of rubber dam
• rubber dam is centered horizontally on the face and the upper lip
is covered by the upper border of the dam and does not cover
the nostrils.
• The minimal number of the holes necessary for good isolation .
• If interproximal lesion restored, at least one tooth anterior and
one tooth posterior to the tooth .
34. Placement of rubber dam
• slit technique : isolation several teeth, punch 2 holes
approximately ½ inch apart and cut the rubber dam and
connecting the 2 holes .
• another method to punch holes : approximately 1 1/4-inch
square in the center of a sheet of rubber dam, each corner of the
square indicates punch holes for the clamp-bearing.
35. Placement of rubber dam
• If the holes are punched too far apart, the dam will not readily fit between the contact
areas.
• if the holes are punched too close together, salivary leakage will contaminate the
operating field.
• The large punch hole: clamp-bearing tooth and per molars.
• The medium sized: the premolars, primary molars.
• The second smallest : maxillary permanent incisors,
• the smallest :primary incisors and lower permanent incisors.
36. Placement of rubber dam
• selecting clamp, place .
• 12- to 18- inch of dental floss on the bow of the clamp .
• Place the clamp on the tooth ,seating it from lingual to bucal direction
• the jaws of clamp are placed below the height of contour and are not impinging on gingival
tissues .
• place the finger on buccal and lingual jaws of clamp and apply pressure to ensure that the
clamp is stable.
• and with index fingers stretch the most posterior hole over the bow and wings of clamp .
• places the frame over the rubber dam.
38. Removing the rubber dam
Rinse away all debris and cut and remove any ligatures.
The clamp, frame, and dam are then removed as a unit with the rubber dam forceps .
Inspect the mouth to see that no small pieces of dam have been left .
Gently massage the tissue around the clamped tooth, and rinse and evacuate the oral
cavity .
39. Optradam
• is an anatomically shaped rubber dam .
• used without metal clamps.
• can easily be placed by one person.
• High patient comfort due to the flexible material .
• Less postoperative discomfort.
41. Matrix Application
Matrices must be placed for interproximal restorations to aid in restoring
normal contour and normal contact areas and to prevent extrusion of
restorative materials into gingival tissues. Many types of matrix bands are
available for use in pediatric dentistry.
42. Matrix Application
Three types of matrix bands are available for use in pediatric
dentistry:
1) T-band:
allows multiple matrices, and no special equipment is needed .
No need for a retainer.
easy wedging.
Easily adapted on any tooth.
Contours itself to the anatomy of the tooth.
43. Matrix Application
2) Spot-welded matrix: allows multiple
matrix placements, and a spot welder is
required.
3)Tofflemire matrix: used infrequently
because it does not fit primary tooth contour,
and is not suitable for use with multiple
matrices.
44. Wooden wedge
used to :
hold the matrix band at the cervical margins.
to retract gingival papilla.
To avoid cutting the interseptal rubber dam and
underlying gingiva.
.
45. Wooden wedge
. Faulty wedging results in:
Concavity in the cervical part of the proximal box, which can be
caused by using too large wedge.
Overhanging restoration, this is caused by the wedging being too
loose.
Open contact which is caused by inadequate wedging pressure to
separate the approximated contacts.
47. Resin infiltration
It is a microinvasive approach in which noncavitated caries lesions are
infiltrated with a low-viscosity resin lesion to strengthen, stabilize, and
limit the lesion's progression.
Indications:
• Small interproximal lesion
• Postorthodontic white spots
48. Introduction
Treatment of interproximal caries usually is limited to two choices:
1-Noninvasive measures include:
• Primary prevention: application of fluorides + improvement of oral hygiene +
dietary control
• Secondary prevention: Enhancement of lesion remineralization .
2- Invasive (restorative):
when noninvasive measures are ineffective, invasive intervention is indicated.
49. • Clinical Application
• Rubber dam is application
• Teeth are separated by flattened wedge.
• A special Applicator(matrix) is inserted between the
separated teeth.
design helps deliver the materials needed for treatment through the
perforations precisely to the lesion and helps protect the adjacent tooth
surface on the non-perforated side.
50. • Clinical Application
• Application of 15%hydrochloric acid etching gel for 2 min .
• water rinsing and air drying
• The infiltrant is applied , After 3 min of application, the infiltrant has penetrated
into the lesion deep enough.
• Excess resin material is removed with a gentle air blow,
• light curing
• A second coat is applied for only 1 min in the same way.
51. • Clinical Application
• Application of 15%hydrochloric acid etching gel for 2 min .
• water rinsing and air drying
• The infiltrant is applied , After 3 min of application, the infiltrant has penetrated
into the lesion deep enough.
• Excess resin material is removed with a gentle air blow,
• light curing
• A second coat is applied for only 1 min in the same way.
53. the steps are identical to the interproximal
application, except for:
1. The location of the lesions
2. the use of a different applicator
54. Class I & class II cavity
preparation for amalgam
and composite
By :
Dr / Najma Mohamed Alamami
alamaminajma@gmail.com
55. Introduction
• The objectives of restorative treatment are to repair
or limit the damage from caries, protect and
preserve the tooth structure, reestablish adequate
function and restore esthetics.
• Restoration of primary teeth differs from restoration
of permanent teeth, due in part to the differences in
tooth morphology .
56. Black & modern cavity preparation :
Modern type
Black type
1)Gain access to the caries.
2)Remove the caries .
3)Plain the cavity outline.
4)Complete cavity preparation.
1)Gain access for cavity preparation not
necessarily to the caries.
2)Prepared the cavity to standard out line
and shape.
3)Remove any remaining caries
57. Tooth preparation for restoration
General considerations:
1) The outline including all retentive
fissures and carious areas
dovetailed
as conservative as possible
58. 2) pulpal floor flat
depth is 0.5 mm into dentin (approximately
1.5 mm from the enamel surface)
slightly rounded
Tooth preparation for restoration
General considerations:
59. 3)cavosurface
margin.
The cavosurface margin should be
placed out of stress-bearing areas.
and should have
no bevel.
cavosurface angle should form
approximately 90° to avoid marginal
deterioration of amalgam
Tooth preparation for restoration
General considerations:
60. 4)The isthmus should be one third of the intercuspal width.
5)The buccal and lingual walls should converge slightly in an occlusal
direction to aid in retention.
6) The mesial and distal walls should flare at the marginal ridge so as
not to undermine the ridges.
Tooth preparation for restoration
General considerations:
61. Class I amalgam
Class I amalgam could be appropriate
if enamel walls can withstand occlusal
forces and the tooth is expected to
exfoliate within 2 years.
62. Class I cavity preparation of amalgam restoration
in primary teeth
• Administer anesthesia
• Rubber dam
• Using a no 330 bur . ( small, rounded-end carbide burs ) in
the high-speed hand piece.
• For the first primary molars, the depth is approximately
1(min) to 1.25mm (maximum),
• for the second primary molars it is1.25mm (min) to
1.5mm (maximum)
Rounded-end, high-speed
carbide burs No. 329,No.
330, No. 245, and No. 256
63. Class I cavity preparation of amalgam restoration
in primary teeth
• Extend the buccal and lingual grooves approximately equal to the width of the 330
bur and create a dovetail.
• For the second primary molar, at least 1.5mm tooth structure must remain on buccal
and lingual grooves, and 1.25mm at the marginal ridges.
• Remove all carious dentin.
• Smooth the enamel walls and refine the final outline form.
• Rinse and dry the preparation.
64. Common errors with Class I amalgam
restorations:
1- Preparation not including all susceptible fissures.
2- Too deep or too shallow cavity preparation.
3- Overextension of the occlusal width weakens the cusps and leaves both
enamel and amalgam poorly supported.
4- Excessive flare of the cavosurface margins.
5- Undermining the marginal ridges.
65. General considerations:
The proximal box should :follow the contour of the
surfaces ,converge occlusally and parallel to the
long axis of the tooth .
The buccal, lingual and gingival walls should all
contact with the adjacent tooth, just enough to allow
of an explorer to pass.
Class II cavity preparation in primary teeth of
amalgam restoration
66. General considerations:
• The isthmus width should be ⅓ the intercuspal distance.
• if the proximal walls flare widely, then SSC would be a better
• The gingival floor perpendicular to the long axis of the tooth.
• No bevel at the gingival margin.
Class II cavity preparation in primary teeth of
amalgam restoration
67. General considerations:
• The axial wall extend 0.5 mm into
follow the proximal contour of the tooth.
• The axiopulpal line angle is rounded to
stress concentration and to provide
bulk of restoration.
Class II cavity preparation in primary teeth of
amalgam restoration
68. Common errors with Class II cavity
restoration:
1) Isthmus cut too wide or too narrow.
2) Too great flare of proximal walls.
3) Angles formed between the axial, and buccal or lingual walls are too
great.
4) Gingival contact with adjacent tooth is not broken.
5) Axial wall is not conforming to the proximal contour of the tooth and
the mesio-distal width of the gingival floor is greater than 1mm.
70. Class I and class II cavity preparation for
composite restoration
The steps in preparation of a primary or
permanent molars for composite resin are
very similar to those for preparation for
amalgam, but with a few alterations.
71. Class I and class II cavity preparation for
composite restoration
Few alterations :
• Incipient lesion can be prepared by using a no. 2
small, round or a no. 330 bur .
• Class I carious lesion that extend into the dentin,
removing all the carious dentin with round bur &
spoon.
72. Class I and class II cavity preparation for
composite restoration
Few alterations :
• It is recommended that a class II preparation is
restricted to the region of the caries with little to no
occlusal extension .
• Extending the proximal box line angles in self-
cleansing area is not necessary.
• A short bevel to the cavosurface is recommended.
73. When class II carious lesion exist on posterior teeth in
the absence of class I lesion, several approaches may be
taken:
1. Modified slot preparation
2. Tunnel preparation.
74. 1. Modified slot preparation :
involves access to the carious lesion
from either the occlusal, buccal or
lingual direction.
75. 2 - Tunnel preparation.
The objective is to maintain the sound enamel in the marginal ridge area.
When the ideal preparation for class I lesion is completed, prepare a
small tunnel toward the proximal carious area using a small round bur.
77. ART
ART or Atruamatic Restorative Treatment – An
approach where carious tooth tissues are removed with
hand instruments and the resultant cavity and adjoining
fissures restored and sealed with an adhesive dental
material, usually glass ionomer.
78. A. The essential hand instruments
include:
• Mouth mirror
• tweezers
• An explorer
• Spoon excavator( small, medium and large)
• Dental Hatchet
• Applier/Carver
• Mixing pad and spatula .
81. DEFINITION OF conservative adhesive restoration (CAR)
• It combines the preventive approach of sealing
susceptible pits and fissures with conservative cavity
preparation of caries occurring on the same occlusal
surface.
• Teeth suitable are those that demonstrate small
,discrete regions of decay, often limited to a single pit.
• do not require anesthesia
82. Clinical Steps of PRRS
1.Isolation of tooth surface
2. Remove caries from isolated pits and fissures
3. Etch, rinse and dry
4. Restore cavity by resin material
5. Apply sealant
6. Check occlusion
7. Periodic re-evaluation
83. Originally three types of CARs were described (types A,B,and C later
changed to types 1,2,and 3)
• Type 1: minimal pit and fissure decay: enameloplasty (
not more than 1/3 the enamel thickness), pit and fissure
sealant.
• Type 2: caries extend to dentine: protective base-
etching, wash& dry, bonding agent, and wear resistance
posterior composite.
• Type 3: as type 2 + pit and fissure sealant applied to
adjacent pit and fissure
85. Restoration of Primary Incisors and Canines
Adhesive materials: resin-based composite or resin ionomer products are
placed into class III and class V restorations in primary anterior teeth.
Class IV restorations may also be done, however if too much tooth structure
has been lost Full Coverage with crown is done.
86. 1) Class III Cavity Preparation in Primary
Teeth
•Steps of Cavity Preparation
• Adminestration of L.A.
• Rubber dam application
• cavity preparation is made (access is achieved labially or
lingually)
( Using no. 330 or no. 2 round bur)
• Caries Removal
• Cavity Restoration (resin-based composite or resin ionomer )
87. Characteristic of Proximal Box
• The box is perpendicular to a line tangent to the
labial surface.
• Gingival, Labial and lingual walls follow the
contour of outer surface.
• Depth of axial wall 0.5mm in dentin .
• Retentive undercuts may be placed.
• Beveling of cavo-surface margin 0.5mm (by fine
tapered diamond or flame shaped finishing bur)
88. Modified class III with labial or lingual locks
Modified slot
preparation with
gingival extension
Slot preparation
Dove tail preparation
in presence of gingival
decay
in very small class
III
(most common)
present in the middle third
not extending half labial/ lingual
surface
just reach dentin
89. Class V Cavity Preparation in Primary
Teeth
More common in adults.
Maxillary and mandibular second molars are
most susceptible
Labial & buccal surfaces are more affected than
lingual.
affect maxillary primary incisors In baby bottle
caries .
90. Class V Cavity Preparation in Primary
Teeth
• Anesethesia is given.
• Rubber dam is applied.
• No. 330 bur is used
• Pulpal wall is convex.
• Depth just reach dentin.
• Caries is removed by low speed rose head bur or sharp excavator.
• Mechanical retention is achieved by No. ½ round bur making a small undercuts in
the :
gingivo axial line angle.
inciso axial line angle.
• Beveling of the entire cavo-surface margin is done.
93. Anterior crowns used in children
• Discoloration may due to carious , congenital
defect or trauma.
• If the decay is extensive, a crown may be
recommended.
• For posterior primary teeth there is nothing
better than stainless steel crowns.
94. • Types of crowns for restoring anterior teeth
Open face stainless steel
crown
Stainless steel crown
Stip crowns
.Ceramic (EZ crowns)
Jacket crowns
Pre veneered
crown(nusmile)
95. 1) “strip crown.”
the resin crown technique
definition
Transparent plastic crown forms used for restoring primary
anterior & posterior teeth.
• So anterior strip crowns with composite resin provides an
aesthetic and durable restoration.
96. Indications of strip crown
1.Extensive or multisurface caries in primary incisors.
2.Congenitally malformed teeth.
3.Fractured or discolored due to trauma.
4.Incisors with large interproximal lesions or hypoplastic
defects or received pulp therapy
5. Incisors with multiple developmental disturbances
(e.g.ectodermal dysplasia)
97. Contra indications of strip crown :
•Minimal amount of enamel left (inadequate for retention).
•Deep overbite.
•Bruxism
•Presence of periodontal disease.
98. Advantages of strip crown :
1. Esthetic.
2. -Better retention than polycarbonate crowns.
3. -Ease of repair if fracture occurred.
4. -Functional; allow for normal incisal wear.
5. -Conservative; small amount of tooth structure is removed.
99. Dis advantages:
1. Fracture or debonding.
2. Time consuming.
3. Technique sensitive.
4. Difficult moisture control in subgingival preparations due to bleeding.
5. More fragile than st.st crowns.
6. May discolor over time.
100. Preparation and Placement of
Adhesive Resin-Based Composite
Crowns (Strip Crowns):
1. Administer anesthesia.
2. Select the shade of composite
3. rubber dam isolation .
101. 4. Select celluloid crown form with a mesiodistal width approximately equal
to the tooth
5. Remove decay with a large round bur in the low-speed handpiece or with
spoon excavators
102. 5. Reduce the incisal edge ( 1.5 mm).
6. Reduce the interproximal surfaces ( 0.5 to1.0
mm).
7. Reduce the facial surface at least 1.0 mm and the
lingual surface by at least 0.5 mm.
• 0.5mm supragingival
• Create a feather-edge gingival margin.
8. Place a small undercut on the facial surface in the
gingival one third of the tooth .
103. 9. Trim the selected crown form by cutting away
excess material gingivally with scissors, and trial fit the
crown form. ((1mm below the gingival crest )).
10. punch a small hole in the lingual surface with an
explorer to act as a vent for the escape of trapped air
and Excess material .
11. Etch the tooth with acid gel for 15 to 20 seconds.
104. 12 .Rinse and dry the tooth; then apply bonding agent
13. Fill the crown with composite ( two thirds)and seat onto the
tooth.
15-Seat the packed crown (1mm below) the gingival margin &
make sure its in proper occlusion.
16. Polymerize the material.from the facial and lingual
directions.
14. Remove the celluloid form by using a composite finishing bur
or a curved scalpel blade .
15. Remove the rubber dam evaluate the occlusion.
16. Little finishing should be required on the facial surface.
106. Stainless Steel Crown:
Introduced by Dr. William Humphrey in 1950.
SSC are prefabricated crown form that are adapted to
individual teeth and cemented on it with a
biocompatible luting agent .
107. Based on shape:
There are three type of SCC based on shape
1-Staright sides untrimmed
2-Pre-trimmed or Pre-festooned
3-Pre-contoured
109. 2-For restorations of multisurface caries.
3-Where an amalgam is likely to fail such as a proximal box
extended beyound line angles.
110. 3- Fractured teeth.
4- Rampant caries and for patients at high caries risk.
5- For primary teeth with developmental defects such as hypoplastic teeth
and amelogenisis and dentigenesis imperfecta.
111. 6- In children with bruxism and extensive teeth wear.
7- As an abutment for space maintainer when both crown and space
maintainer are required.
112. Indications for young permanent molar teeth
1-Interim restoration of a broken-down or traumatized tooth .
2-Teeth with developmental defects .
3- Restoration of permanent molar which requires full coverage
but is only partially erupted.
113. Clinical procedures
Primary molars
(1) Steps of preparations:
(A) Evaluate the preoperative occlusion:
To check the following:
1-The opposing tooth has extruded due to long standing carious lesion.
2-Mesial drift due to proximal caries.
3-Cusp-fossa relation bilaterally.
114. (B) Local anesthesia administration and rubber dam application:
Rubber dam for isolation with the placement of wooden wedge to
avoid damaging of the adjacent tooth structure.
115. (C) Deepening of the occlusal grooves:
Use the tip of the bur ( 169 L fissure bur or diamond bur )
the occlusal grooves by 1- 1.5 mm through the buccal ,
proximal surfaces.
(D) Reduction of the Cusps:
Sweep the side of the bur mesiodistally over each cusp so
occlusal surface is reduced by 1-1.5 mm comparing the
marginal ridges and following the original anatomy exept
pulpotomy or pulpectomy is performed.
116. (E) Proximal reduction:
Hold the bur (169 L ) slightly convergent to the occlusal slightly back from
sweep bucco-lingually till:
1-Contact is broken so explorer pass between adjacent teeth
2-Proximal slices are slightly convergent to occlusal
3-Proximal slices end in a feather edge at the gingival crest with no ledges or
interfere with crown seating
4-Proximal slices are straight when viewed from occlusal with proper angulations
lingually.
5-Proximal slices are smooth
118. •
(F) Roundation of sharp edges:
•
-Bevel the occluso-buccal and occluso-lingual line angles by sweeping the
bur mesio-distally at 3o degree - 15 degree angle to the occlusal surface.
•
-Round the gingival border of the bevel.
119. (G) Buccal and Lingual reduction:
OPTIONAL
Where there is a large buccal bulge interfering with the seating of the crown.
Minimal reduction of 0.5 – 1 mm
Original anatomy is preserved
Reduction end in feather edge at gingival crest
120. Some tips
1- trying the selected crown for size before carrying out any lingual or
reduction
2-To obtain retention , the crown must seat subgingivally to a depth of
and a degree of gingival blenching seems to be acceptable
3-The buccal cervical ridge is the most important factor in the SCC
reduction of the buccal surface lead to loss of the retention
121. (2)Crown selection:
Three main consideration in selecting the proper SCC:
1-Adequate mesio-distal diameter.
2-Light resistance to seating.
3-Proper occlusion height.
122. (3) Crown contouring and adaptation:
It may be necessary to remove the rubber dam at this stage
1-After a proper crown is selected, place on prepared tooth from buccal to palatal in
teeth and from lingual to buccal in mandibular teeth and seat completely.
2- Mark gingival margin with an explorer or scaler and remove the crown. Reduce the
margin of the crown with the heatless stone 1mm below mark on crown.
3- If space loss has occurred, the crown can be squeezed with flat nosed pliers to a
in order to fit in a narrow mesio-distal space.
123. 4-Use #114 pliers to contour buccal and lingual surfaces of the crown. In
oreder to:
• -provide mechanichal retention of the crown
• -protection of the cement from exposure to oral fluid
• -maintainance of the gingival health
5-Use # 800-417 crown crimping pliers around the entire margin of
crown (crown should now be adapted to the normal anatomy of the
tooth).
125. 6-Again try the crown on by seating on the prepared tooth..the crown
should “Snap” into the correct position
7-Check margins with a explorer. Margins should be well adapted to
the tooth structure.
126. 8- Check the occlusion.
9-In order to remove the crown, a large spoon excavator can be used to
dislodge the crown off the tooth.
128. The crown margin should have:
-smooth edges
-knife-edge margins
-smooth curved margins
-no bend
-no scratches
129. (5)Crown cementation:
…The following cement can be used:
1-Polycarboxylate cement.
2-Glass ionomer cement.
3-Zinc phosphate cement.
4-Adhesive cement.
130. Steps of cementation:
1-Before cementation a cavity varnish must be applied on a vital tooth.
2-Clean and dry the crown and the tooth .
3-Fill the crown with the cement while the mix is glossy.
4-Seat the crown firmly into occlusion, instruct the patient to bite on a tongue blade or
band seater to ensure complete seating.
5-Remove excess cement with explorer on labial and lingual and with floss
interproximally
6-Make a final check and follow up.
131. Placement of adjacent crown:
…. It is similar to previous technique but with additional factors:
1-Prepare the occlusion reduction of one tooth completely before the
beginning at the other tooth to avoid under-reducing both.
2-Contact between adjacent proximal surfaces should be broken
approximately 1.5 mm space at the gingival bevel.
3-It is generally best to begin placement and cementation of the
crown first.
132. Reasons for Failures of Stainless Steel
Crowns
1- Poor tooth preparation.
2- Poor crown retention and adaptation.
3- Poor cementation technique.
4- Occlusal surface of crown wears through due to heavy bruxism.
5- Poor distal margin adaptation allows permanent molar to erupt
ectopically under a second primary molar.