Keyence VH profilometer

This device can perform an optical scan of an object up to about the size of 50mm. The scans take about 30 ​seconds. The resolution in the x-y is about 1 micron. And in the z-axis it is ??. Unfortunately, the machine is ​not helpful in measuring Ra values below 1 micron. The machine comes with built-in analysis software that ​can volumes and areas. We use this machine mostly for wear testing to measure small divots caused by our ​wear machine. We can also use the machine to measure the volume of enamel lost after wear testing.

UAB wear testing machine

This is a custom device that can create impact and sliding wear. A 15N load is applied (this load cannot be ​varied) and then a distance of 1.8mm of sliding occurs. We can mount specimens into brass holders with ??​mm circular openings (??mm depth). The antagonist can either be a 2.5mm diameter ball (SS or ceramic ball ​bearing) or anything that can be mounted into a socket screw hear (ie enamel cusps). The machine ​accommodates 4 specimens. The test is run in 33% glycerine at room temp. The machine runs for 400,000 ​cycles for 60-80 cycles/second. The test takes 3-4 days. We have 2 machines but they give slightly different ​results and both machines are never used for the same project.

Universal testing machine

Instron 5565 with a 5kN load sensor and Bluehill 2 Software. This machine is used to measure load in ​compression and tension. The crosshead can be moved at various speeds and load measured or it can be ​kept at a constant distance and applied load measured. We have fixtures to allow us to do various tests with ​this machine:

3-point bend flexural strength testing: We have fixtures to accommodate a 20mm span length (ceramic and ​composite) or ??mm span length (dentures and nightguards). These allow measurement of maximum strength, ​modulus (calculated automatically through software), maximum flexure and energy (area under the curve). ​We can also make specimens with notches to test fracture toughness (we don’t have the capability to make ​the notches for ceramic specimens.

Biaxial flexural strength testing: This fixture also calculates strength but uses a disc supported by 3 balls ​rather than a bar supported by 2 rods. These specimens are often easier to make but don’t allow calculation ​of modulus.

Crown crush or crown pull: These are custom tests in which crowns are supported on tooth or resin dies and ​either compressed until failure using a metal indenter or removed in tension with a metal wire.

Ultradent shear bond strength: Specimens of tooth or restorative material are mounted in acrylic, polished ​flat and then a small tube of composite is bonded to their surface. The tube is then sheared off using a ​notched-edge blade.

Fatigue machine

This is a custom machine originally designed for wear testing (however the sliding component is no longer ​functional). It applies a 50N vertical load. The antagonist can accommodate anything that can be mounted in ​a ?? diameter screw head. The specimens can be anything mounted into a ?? diameter brass holder. The test ​is run in water.

Specimen preparation area

This station has a polishing wheel, a model trimmer, a sectioning saw, and a sectioning table saw.

Digital specimen preparation area

We have an Primemill and inLab CAD software. We have a Programmat furnace for glass ceramics (not for ​zirconia). We also have access to 3shape design software and Exocad. We have a ProS55 and Pro95 ​Sprintray DLP vat printers, the associated cure boxes and a wash station.

Keyence VHX

This is a digital light microscope for transmission and reflectance microscopy. We have a 5-40x and 100-​1000x lens.

This is a device for measuring gloss. The aperture for measurement is ??. It can take measurements in about ​3 seconds.

Fatigue machine 2

This fatigue machine is set up to test the strength of biaxial flexural strength specimens in fatigue. It has a ​programmable load profile which goes up to 400N. Specimens can be tested under water.

Microhardness machine

For measuring Vicker’s microhardness. There is a digital camera attached which allows digital measurement ​of the indents on the computer.