Source: Manufacturer's published data
SUMMARY: Crystal Ultra is by far the strongest esthetic ceramic material, higher than 3M Lava Ultimate, and higher than e.max, vita mark II and empress CAD, making Crystal Ultra the toughest dental material in use for cosmetic, minimally invasive and implant dentistry.
SCIENCE: The higher compressive strength of Crystal Ultra is the result of special manufacturing processes used to bond the glass and polymer materials, including the use of a special sylanated glass ceramic which chemically bonds to the polymers, as compared to other hybrid or ceramic materials that form no such chemical bond.
Compressive strength, which best simulates chewing forces in the mouth, is measured by applying both upward and downward pressure on an object until it breaks. Unlike Flexural Strength, which similates breaking a stick over your knee and is measured many different ways according to different international standards, compressive strength is measured only one way according to one ISO standard.
STANDARDS: Compressive strength is measured according to International Standard ISO 4049 and ADA Specification 27. Crystal Ultra specimens were tested in a universal testing machine at a crosshead speed of
1mm/min. Data were obtained in KGF and transformed into MPa using the following formula:
RC = F x 9.807 / A
- RC = compressive strength (MPa),
- F = recorded force (kgf) multiplied by the constant 9.807(gravity), and
- A = base area (7.06 mm2)