Ceramics in dentistry

1. Dental Ceramics
Yaman Yousof DDS MDS PhD

2. Ceramic restorations
Metal-ceramic
All-ceramic (metal-free)
(Sakaguchi et al., 2019)
Monolithic
Layered

3. A B C
Porcelain fused to metal (PFM) (A), all-ceramic layered (B) and all-ceramic monolithic (C) crowns
(Powers & Wataha, 2017).

4. Ceramic particles are heated to a temperature at which only the surfaces of the particles
melt. The particles then fuse (or sinter) together at their surfaces. Ceramics shrink
significantly from the green state to the fused state (Powers & Wataha, 2017).

5. Ceramics are composed of arrays of metal atoms and oxygen held together by ionic
bonds. These ionic bonds are strong and do not tolerate distortion, therefore ceramics
will fracture if distorted even slightly (Powers & Wataha, 2017).

6. Ceramics contain areas (phases) that
are glassy and areas that are
crystalline. In glassy areas, metal ions
called fluxes (like sodium or potassium)
interrupt the arrays, and these areas
tend to be transparent. Crystalline
areas have more ideal crystal structure,
and these areas are opaque (Powers &
Wataha, 2017).

7. Ceramics can be divided into four
categories. Glassy ceramics (A) consist of
mostly amorphous glass with islands of
crystalline phase. Glass-dominated
ceramics (B) have mostly glassy phase but
have increased abundance of crystalline
phase. Crystalline-dominated ceramics (C)
have mostly crystalline phase but have
glassy phase that surrounds the crystals.
Finally, crystalline ceramics (D) have no
glassy phase (Powers & Wataha, 2017).
A B
C D

8. Feldspar Sodium or Potassium Aluminosilicate (Na, K)AlSi3O8 Glass phase
Silica Silicon dioxide SiO2 Glass phase
Fluorapatite — Ca5(PO4)3F Crystal phase
Leucite Potassium Aluminosilicate KAlSi2O6 Crystal phase
Lithia silicate Lithium disilicate Li2Si2O5 Crystal phase
Spinel Magnesium Aluminium oxide MgAl2O4 Crystal phase
Alumina Aluminium oxide Al2O3 Crystal phase
Zirconia Zirconium oxide ZrO2 Crystal phase
Strength
Low
High
Components
Translucency
High
Low

9. (Powers & Wataha, 2017)
(Slip-cast glass-infiltrated)
(Sintered)

10. Classification of dental ceramic materials with examples of products and their manufacturers (Sakaguchi et al., 2019)
Application Fabrication Crystalline phase Products Manufacturers
All-ceramic Soft machined Zirconia (3Y-TZP) Cercon Dentsply International
Lava 3M Company
IPS e.max ZirCAD Ivoclar Vivadent
In-Ceram YZ Vita
Hard machined Lithium disilicate IPS e.max CAD Ivoclar Vivadent
Leucite IPS Empress CAD Ivoclar Vivadent
Heat pressed Leucite IPS Empress Ivoclar Vivadent
Lithium disilicate IPS e.max Press Ivoclar Vivadent
Fluorapatite IPS e.max ZirPress Ivoclar Vivadent
Sintered Leucite IPS Empress
layering ceramic
Ivoclar Vivadent
Metal-ceramic Sintered Leucite VMK-95 Vita
(Sakaguchi et al., 2019)

11. Properties of dental ceramics
• Esthetics
• Hardness
• Abrasion resistance
• Compressive strength
• Tensile strength
• Flexural strength
• Thermal conductivity
• Biocompatibility
• Firing shrinkage 10-30%

12. Dental Ceramics
Microstructure
Glass ceramics (GC)
Crystalline ceramics (CC)
Composition
Firing temperature
High fusing >1300°C
Medium F. 1100-1300°C
Low fusing 850-1100°C
Ultra low F. < 850 °C
Fabrication process
Stacked (sintered) ceramics
Castable glass ceramics
Slip-cast glass infiltrated
Heat-pressed ceramics
Soft machined (milled)
Hard machined (milled)
Feldspathic GC
Leucite-reinforced GC
Fluorapatite-reinforced GC
Lithium disilicate ceramic
Spinel-reinforced CC
Alumina-reinforced CC
Zirconia-reinforced CC
Zirconia (3,4,5)Y-TZP CC
Y-TZP: Yttria-stabilized Tetragonal
Zirconia Polycrystal ceramics.

13. References
Gladwin, M., & Bagby, M. (2013). Clinical Aspects of Dental Materials: Theory,
Practice, and Cases (Fourth Edition). Lippincott Williams & Wilkins, A Walters
Kluwer Business.
Manappallil, J. (2016). Basic Dental Materials (Fourth Edition). New Delhi: Jaypee.
Powers, J. M., Wataha, J. C. (2017). Dental Materials: Foundations and Applications
(Eleventh Edition). Elsevier.
Sakaguchi, R., Ferracane, J. & Powers, J. (2019), Craig's Restorative Dental Materials
(Fourteenth Edition). Philadelphia: Elsevier.