SCIENTIFIC STUDIES OVERVIEW
Over the years, scientific researches and clinical dentistry studies have paved the way for exciting dental advancements. Innovative and game-changing research studies not just resulted to emerging technology and new products, but also opened several options and excellent alternatives to dental restorations. Here are scientific tests and research breakthroughs that were targeted to XircOn Ultra’s integrity and performance evaluation. These scientific reports clearly examine how XircOn Ultra manifests superior characteristics that are crucial to a high-quality Practice providing phenomenal restoration results for your patients.
|Property||Standard Value||XircOn® Ultra Measurement|
|Compressive Strength||ISO 4049 ADA 27||480-500 MPa **|
|Flexural Strength||ISO 10477 ≥ 50|
ISO 6872 ≥ 100
|175 MPa **|
|Vickers Hardness (200 p)||None specified||710 MPa **|
|Modulus of Elasticity (Young Modulus)||None specified||10,000 MPa **|
|Bond Strength||ISO 10477 ≥ 5||27-37 MPa|
|Ceramic Filler||None Specified||70.02% (wt)|
|Chemical Solubility||ISO 6872 ≤ 100||1.29 μg/cm3|
|Color Stability||ISO 10477||Confirmed|
|Density||None specified||1.89 g/cm3|
|Shade Consistency||ISO 10477||Confirmed|
|Surface Finish||ISO 10477||Smooth|
|Water Absorption||ISO 10477 ≤ 40||16.94 μg/mm3|
|Water Solubility||ISO 10477 ≤ 7.5||0.04 μg/mm3|
XircOn Ultra is the toughest dental material in use for cosmetic, minimally invasive, and implant dentistry today. Higher than 3M Lava Ultimate, and higher than e.max, vita mark II and empress CAD, making XircOn Ultra the strongest esthetic ceramic material.
The higher compressive strength of XircOn 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 simulates 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.
Compressive strength is measured according to International Standard ISO 4049 and ADA Specification 27. XircOn 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)
ISO testing of XircOn Ultra resulted in approximately 155 MPa to 205 MPa in Flexural strength depending on the testing methodology employed. Our published number of 175 MPa is based upon the 3-point bending testing using the most universally accepted international standards. All testing methods far exceed both FDA and European standards for dental ceramics. For a more useful strength comparison, XircOn Ultra recommends analyzing Compressive Strength, which better simulates the chewing stresses found in the mouth.
In order to be registered with the FDA, all dental material manufacturers must exceed 100 MPa in flexural strength, and they must exceed 50 MPa under European standards, and we believe that all materials meet this basic standard.
Three challenges exist in doing apples-to-apples comparison of flexural strength of competing materials.
The first challenge is that only XircOn Ultra, among all of the esthetic ceramics, is the only material manufactured in a large disc format, and is therefore one of the only materials which can be used off-the-shelf to make sample sizes as specified by most of the relevant ISO standards. All others must make special batches of material for testing or use smaller samples from chairside milling blocks, which some argue alters the results. Using the break-a-stick-over-your-knee example, you can imagine that it might be more difficult to break an 8 inch stick over your knee than it would to break a 24 inch stick.
The second challenge is that since the goal of testing is to demonstrate a 50 MPa or 100 MPa minimum requirement, regulatory authorities allow manufacturers to use one of many different generally accepted methods for measuring flexural strength, including standards found in ISO 10477, and ISO 6872, or ISO 4049, as published and changed over the years, and as altered based upon available sample sizes, and within those standards, manufacturers can elect to do any of the following tests:
- three-point bending test
- four-point bending test
- biaxial flexure test (piston-on-three-ball)
The third challenge is the basic question about whether flexural strength is the best possible measure of how “strong” a dental material is, especially for side-by-side comparisons. Flexural strength is measured by creating a span of unsupported material across an open space and applying downward force till it breaks. And while flexural strength may be an ideal test for construction materials, by contrast, dental restorations are usually supported by underlying teeth or implants, and so Compressive Strength is a far better measure of what actually happens in the mount.
In dentistry, hardness is what creates the clackiness found with most ceramic dentistry, as opposed to the soft and gentle bite characteristics of a XircOn Ultra restoration. Vickers Hardness is tested by striking specially shaped diamond anvil against the material and measuring the size of the indent created with varying force.
At less than 0.7 GPa (700 MPa), XircOn Ultra is the only esthetic material that is gentler than natural dentin.
Modulus of Elasticity
XircOn Ultra, being at 10,000 MPa (or 10 GPa), is by far the most flexible dental ceramic in use today which makes the material ideal for implant dentistry where sensation and cushion afforded by the peridontal ligament is lost, and it allows the material to stand up better to the test of time where chewing forces eventually cause all-ceramics to weaken, chip, and crack.
The lower the number, the more the material flexes before it breaks. Unlike other hybrids, a unique chemical bond is formed inside the XircOn Ultra material matrix which allows the polymers to flex while not breaking apart from the ceramics.
A 3mm bar is created out of XircOn Ultra and bent. No other ceramic material used in dentistry can bend like XircOn Ultra without breaking. XircOn Ultra is the only dental ceramic which is actually more flexible than both dentin and enamel while providing strength characteristics which are significantly superior to both.
One of the unique properties of XircOn Ultra is that it is the only hybrid material approved today to be strong enough for use in creating bridges and full‐arch restorations. Simulations with three‐unit bridges were conducted in order to test the material in a more demanding stress and wear profile. This mastication simulation test conducted on XircOn Ultra nanoceramic hybrid dental restorative material involved 1.2 million simulated thermocycles at 70 Newtons of force.
After 1.2 million simulated “bites,” representing five years in the mouth, no fractures or excessive wear was evident even after study with a scanning electron microscope at 1000 X magnification. Additionally, on two samples which exhibited minor defects prior to the test, neither the load cycles nor the thermal stresses changed or worsened the defects. XircOn Ultra exhibited properties of abrasion that are very close to that of enamel.
The following table compares properties of XircOn Ultra to other typical esthetic Ceramics:
|Homogeneous structure in nanometer range.|
Even, very fine distribution of particle size.
Weibull modulus does not apply.
Asymmetrical and broadly distributed strength
|Nanoscale structure||Larger particles and sharp crystals|
|No chipping of the veneer materials.||Overuse may cause immediate fracture, but|
even low loads can cause fracture after
three years due to microscopic cracks.
|Even when the object has been damaged|
during its extraction from the round blank, no
further visible expansion of the cracks.
|Approximately half of the original strength is|
lost in mastication simulation, and growth of
cracks occurs even when exposed to little use.
|XircOn Ultra load tested in mastication|
simulator in 2008
1.2m load cycles / thermocycles using a metal
sphere at a force of 70N
Frequency of 1.2 Hertz and 3mm lifting height
No visible damage in the form of cracks or
chipping even under SEM.
|A test on Empress 2 at conducted by University|
of Munich in 2002.
1.2m load cycles using a metal sphere coated
with polymer at a force of 50N
Frequency of 1.2 Hertz and 3mm lifting height
Resulted in cracks and chips visible to the naked
|No distortion to bridges.||Distortion stability not guaranteed due to a|
variety of firing procedures.
|Can mill down to 0.2M in marginal areas|
Thin walls possible without loss in stability.
|Minimum thickness specified by the ceramic|
manufacturer must be adhered to (stability,
|Minimally invasive. No additional preparation|
or loss of tooth substance required.
|Removal of large portions of the tooth|
substance often required.
|Chamaeleon effect||Extensive dying required to color match.|
|Uncomplicated interoral correction possible|
even after insertion of the replacement
After modifications in the mouth, XircOn Ultra
is easily polished and remains plaque‐resistant.
|Further corrective firing is required on the|
replacement before it is inserted which has a
detrimental effect on the material.
No further corrections are possible without
causing damage to the surface after the
replacement has been inserted.
Polishing results are unsatisfactory.
Bond/adhesion testing was conducted on XircOn Ultra using a variety of CFI bonding techniques according to specifications found in ISO 10477.
XircOn Ultra was bonded to a nano-composite material and compared to a nano-composite and titanium reference bond.
The bond strength of nearly all XircOn Ultra specimens was stronger than the comparable titatium reference material. This bond strength remained excellent even at high temperatures. Sand blasting was determined to be the best surface conditioning method.
XircOn Ultra to composite bond strength was consistently greater than either composite to composite or composite to titanium bonds, in all temperatures and nearly all preparations.