This document discusses the use of zirconia crowns for primary anterior teeth. It provides information on the physical and mechanical properties of zirconia that make it suitable for dental crowns, including its strength, hardness, and biocompatibility. The document presents results from a pilot study comparing the wear of enamel from zirconia and alumina materials, finding that zirconia's wear rates are within normal enamel wear rates and comparable to alumina. Clinical cases are presented showing zirconia crowns on primary anterior teeth with no excessive attrition over follow-up periods of 1-3 years.

1. Sung-Ki Kim
Pusan National University
CDC Haeundae Children’s Dental Clinic
Korea

2. Requirements
for Primary Anterior Crowns

6. 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

7. WHAT IS ZIRCONIA?
• Physical property : close to metal
• Color : tooth-like
• “Ceramic Steel”

8. 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.

9. Scanning electron microscopy(SEM) observation of
fibroblasts cultured on zirconia : cells grow on the
whole zirconia surface, covering it with a cellular layer.

10. Place subgingivally

11. Zirconia as a material for dental crowns
• Behaves as an antibacterial shield
• Improves cellular adhesion and
proliferation of fibroblast
• Generates gingival attachment and
reconstruction of the papilla

12. Advantages of zirconia crowns
• Esthetics in addition to strength
• Biocompatibility
• Chair-time decreased
• No impression : only 1-visit

14. Resin-bonded luting has proved to be the best
choice for Zr-ceramic restorations, although the
use of conventional cementation may also be
permissible.

15. 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 GIC)

16. Dental wear

17. 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.

18. 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

19. Material
X-axis wear
(mean/year)
Y-axis wear
(mean/year)
Depth
(mean/year)
Zirconia
24.87 ㎛/year
23.03 ㎛/year
17.12 ㎛/year
Alumina
23.96 ㎛/year
23.99 ㎛/year
13.70 ㎛/year
Zirconia is not harmful
Normal wear rates of enamel :
8-30 ㎛/year
(depending on the study)

20. Post-treatment(immediate)
2010.03.1
5
1M
3M

21. 8M
10M
13M
1Y 9M

22. 2Y
2Y 5M
2Y 8M
3Y 3M, last week

23. No excessive attrition

24. Clinical Cases

25. 2011.05.27
Palatal view
not fully erupted
Restored with composite resin

26. 3M after treatment
Palatal view

27. 6M after 1st. treatment
Palatal decay is found
Notice : axis of tooth is
inclined palatally
Axis of tooth is corrected

28. 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

29. 2Y after 1st. treatment/
1Y 4M after last treatment
No excessive attrition

30. 2010.09.10

31. Post-treatment(immediate)
1M
not corrected yet
2M : crossbite corrected
4M : occlusion is stable

32. 7M
1Y 3M
1Y
2Y 4M

33. 2Y 4M
No excessive attrition

34. After cementation. asymmetric
Reduction of incisal edge
3M

35. Buccal view
2013.04.30
Pre-treatment occlusion

36. Preparation(more
than that of SSC)

37. Post-treatment(immediate)
Post-treatment occlusion

38. Buccal view
Slight marginal exposure
1 week later
occlusion

39. Summary
Esthetics in addition to strength
Biocompatibility
No excessive attrition

40. kimsungki99@gmail.com