suction andisolationCoarse tapereddiamond or carbidebur - trim 2Check fit of Try-InCrownAdjust prep asneededClean and dry prepApply primerApply cementSeat crownRemove excesscementCheck occlusion andcontactsPolish cementInstruct patientSchedule recall
Similaire à suction andisolationCoarse tapereddiamond or carbidebur - trim 2Check fit of Try-InCrownAdjust prep asneededClean and dry prepApply primerApply cementSeat crownRemove excesscementCheck occlusion andcontactsPolish cementInstruct patientSchedule recall
Similaire à suction andisolationCoarse tapereddiamond or carbidebur - trim 2Check fit of Try-InCrownAdjust prep asneededClean and dry prepApply primerApply cementSeat crownRemove excesscementCheck occlusion andcontactsPolish cementInstruct patientSchedule recall (20)
Glomerular Filtration rate and its determinants.pptx
suction andisolationCoarse tapereddiamond or carbidebur - trim 2Check fit of Try-InCrownAdjust prep asneededClean and dry prepApply primerApply cementSeat crownRemove excesscementCheck occlusion andcontactsPolish cementInstruct patientSchedule recall
2. Strip crown
Open-faced SS crown
discoloration
total failure
chipping
Durable △
Retentive O Esthetic X
Durable X
Retentive X
Preveneered SS crown
Durable △
Retentive O
Esthetic △
Esthetic O
3. WHAT IS ZIRCONIA?
• Physical property : close to metal
• Color : tooth-like
• “Ceramic Steel”
5. The word “Zirconium” is derived from
the Arabic word “Zargon” which
means “golden in color”.
6. Zirconia in its natural state is a
polycrystalline ceramic without a glass
component. It is a polymorph that occurs
in three forms:
7. Pure Zirconia at room
temperature occurs in the
Monoclinic form and is stable
to 1170 °C
Above this temperature it
transforms to the Tetragonal
structure
And further to the Cubic
phase at 2370 °C
8. • The volume expansion caused by the cubic to
tetragonal to monoclinic transformation induces
large stresses, and these stresses cause ZrO2 to
crack upon cooling from high temperatures.
• When the zirconia is blended with some other
oxides, the tetragonal and/or cubic phases are
stabilized.
• Effective dopants include magnesium
oxide(MgO), yttrium oxide(Y2O3, yttria), calcium
oxide(CaO), and cerium(III) oxide(Ce2O3).
9. • By adding small percentages of yttria,
these phase changes are eliminated, and
the resulting material has superior thermal,
mechanical, and electrical properties
(PSZ : partially stabilized zirconia).
10. • For dental use ;
• Yttrium tetragonal polycrystals : Y-TZP
• Stabilized by adding 3mol% yttria
12. In the late 1960’s , the
development of Zirconia
as a biomaterial was
refined. The first
recommended use of
Zirconia as a ceramic
biomaterial was in the
form of the ball portion of
the femur head in total hip
replacement.
13. Zirconia Ceramics in Dentistry
Endodontic Posts
Implant posts and abutments
Crown and bridge frameworks –
porcelain veneered
14. Its physical, mechanical (i.e., high strength, hardness,
wear resistance, resistance to corrosion, modulus of
elasticity similar to steel, coefficient of thermal
expansion similar to iron, and elevated fracture
toughness) and chemical properties make zirconia a
material of interest for biomedical sciences.
15. Scanning electron microscopy(SEM) observation of
fibroblasts cultured on zirconia : cells grow on the
whole zirconia surface, covering it with a cellular layer.
21. Advantages of zirconia crowns
• Esthetics in addition to strength
• Biocompatibility
• Chair-time decreased
• No impression : only 1-visit
22. Monolithic Zirconia Primary Crowns
Advantages
• Lifelike esthetics to rival custom laboratory fabricated crowns
• Proven durability in adult dentistry for more than 10 years
• Good alternative for patients sensitive to nickel
• Full coverage protection
• Minimal chair time
• Tooth reduction similar to SSC
• Can be repeatedly autoclaved
23. Monolithic Zirconia Primary Crowns
Disadvantages
• No crimping – tooth must be prepared to fit crown
• Saliva and hemorrhage must be controlled
• Cost
• Learning curve at outset
24.
25.
26. Resin-bonded luting has proved to be the best
choice for Zr-ceramic restorations, although the
use of conventional cementation may also be
permissible.
30. Classification of Resin Cement
Bonding agent +
ceramic primer
Self-etching
primer to dentin
One component
One component
31.
32. • Introduced 10 years ago
• Preservation of smear layer : no
postoperative sensitivity
• Water resistance
• Fluoride release
• Physical properties : similar to resin cement
• Minimize the possibility of contamination by
simplifying procedures
39. Zirconia crowns for
primary anterior teeth
• Strong adhesive strength like permanent crown
is not necessary
• Bleeding
• Passive fit : hard to hold the crown in the
proper position
Recommendation : Light-cured
cement (resin or RMGI)
45. Dental wear is defined as tooth loss or surface damage
caused by direct contact between teeth or between
teeth and other materials. Dental wear, one of the
physiological phenomena that are experienced in a
The surface hardness and friction coefficient are
lifetime, occurs as a complex form of chemicalof
commonly used to estimate the degree of wear and
mechanicaldental materials. Conventionally, greater
restorative wear.
Accordinghasscientific studies, however, there is no
hardness to been believed to cause more wear.
significantmore wear was expected from zirconia, as
Therefore, correlation between the restoration
hardness and the degree of wear of antagonistic teeth.
zirconia has strong surface hardness.
On the other hand, the degree of wear is more affected
by the surface structure and the roughness of the
restorations or environmental factors.
46. Wear of Pediatric Enamel by Different
Ceramic Materials (Pilot Project)
Gary Frey, DDS
Davette Johnson, DDS
Houston Center for Biomaterials and Biomimetics
University of Texas School of Dentistry at Houston
7500 Cambridge St. Suite 5350
width
height
Houston, TX 77054-2008
Stylus
Material
X-axis wear
Y-axis wear
Depth
1
Zirconia
93.6 microns
98.8 microns
46 microns
3
Zirconia
118.2 microns
110.6 microns
112 microns
5
Zirconia
93.2 microns
75.1 microns
75 microns
7
Zirconia
94.8 microns
85.3 microns
41 microns
2
Alumina
100.2 microns
95.3 microns
42 microns
4
Alumina
101.6 microns
88.3 microns
57 microns
6
Alumina
94.3 microns
105.0 microns
54 microns
8
Alumina
87.3 microns
95.3 microns
66 microns
Using a Leinfelder style in-vitro wear-test apparatus, 800,000 cycles
47. What about wear to opposing primary teeth?
Zirconia Stylus Tips
Wear screening performed with
LEINFELDER testing instrument
Frey et al., Houston Center for Biomaterials and Biomimetics (2012)
62. An Important Note for the Preparation and
Placement of NuSmile ZR Crowns
• For SSC’s the crown is modified and adapts to fit the prep
• For NuSmile ZR Crowns, the prep must be modified to fit
the crown
63. Why is Light Transmittance and Particle
Size / Density Important in Pediatric Dentistry?
64. Larger particle size allows more light transmittance risking dark
tooth show-through and can impact strength of zirconia
Crown X
Crown Y
65. 1. Microstructure
Requirement for ISO 13356 that the average grain size be under 0.40µm
NuSmile ZR(0.38µm)
Crowns X(0.35µm)
Crown Y(0.67µm)
74. Using Try-In Crown select
crown size that is closest to
original tooth size
75. Trial Fit with pink Try-In Crown
Think Pink! Use of Try-In crowns prevents contamination
to actual ZR crown being cemented
76. • Check fit and alignment
Try-In Crowns - labial
Try-In Crowns - palatal
Final crowns
cemented
77. Fracture load value of ZR Crowns according to the repeated heat sterilization
800
o
Heat sterilized at 121 C for 20min
(according to Lava Zirconia Sterilization Guidelines)
Fract ure Load(N)
700
600
500
400
300
200
- Model of crowns: D5R
100
0
o
- Already reannealed at 1350 C
0
5
10
15
20
25
Number of Repet it ion
Repetition number increased, it was irregularly deviated from the straight line but it was
not affected by the 25-repeated sterilization.
78. Methods for Controlling Hemorrhage
•
Move to another Tx area, then return
•
Pressure or interpapillary injection of
vasoconstrictor
•
Superoxyl, ferric sulfate, hydrogen peroxide
•
Retraction cord
88. Coarse tapered
diamond or carbide
bur - trim 1.5-2mm off
incisal edge and
break interproximal
contacts
89. Black stripe – 5855
Carefully prep tooth
supragingivally to avoid
tissue masceration
90. Green Stripe - 6852
Use a fine thin tapered diamond –
create a feather-edge margin 1-2mm subgingivally
Make sure no subgingival shoulders
or ledges remain
97. • Science based development of anatomy
• Ideal thickness for strength and minimum tooth
reduction
• First primary molars also available in narrow for
cases with mesial-distal space loss
• Sizes 1-7 for each tooth
• Microscopically scratch free surface reduces wear
and plaque accumulation
• Knife edge (0.2mm) margin and cervical contours
for optimal fit and gingival health
98. Case Selection
• Utilize anytime a standard SSC would be used
• Avoid cases with severe crowding or severe
mesial-distal space loss
• Some clinical crown remaining
• Single crown placement is best for beginning cases
102. Tooth Preparation
Use a football or coarse tapered diamond to
reduce the occlusal surface of the tooth 1-2mm
following occlusal contours.
103. Black stripe – 5855
Carefully prep tooth supragingivally to avoid tissue
masceration. Reduce the tooth 20% overall or 0.51.25 mm on all planes of the tooth.
104. Green Stripe - 6852
Use a fine thin tapered diamond - create a
feather-edge margin 1-2mm subgingivally
Make sure no subgingival shoulders
or ledges remain
123. 6M after 1st. treatment
Palatal decay is found
Notice : axis of tooth is
inclined palatally
Axis of tooth is corrected
124. 10M after 1st. Treatment /
2M after last treatment
1Y after 1st. treatment/
4M after last treatment
1Y 8M after 1st. treatment/
1Y after last treatment
1Y 4M after 1st. treatment/
8M after last treatment
125. 2Y after 1st. treatment/
1Y 4M after last treatment
No excessive attrition