Keystone Flex Diamond Discs · Sep Flex Fine, .007" · Single

• Diamond burs — The general range, sold by shape and grit; the finer grades and the laboratory shapes are separated out on this shelf.
• Fine diamonds — The fine end of the grit range, where the coarse grades are described as indicated for more aggressive cutting of tooth structure.
• Non-sterile — Supplied unsterilized, so it is processed before first use, where a single-use diamond arrives ready and is discarded after one patient.
• Laboratory diamond burs — Runs on the bench, on the device; the rest of the shelf runs in the mouth.
• Diamond discs — A disc, which is the one form ISO 7711-1 leaves out of the general diamond standard.

Grit: ISO 7711-1 covers designation, colour code and grit sizes for all shapes of diamond rotary instrument except discs. A study describes coarseness as known for high cutting efficiency and used where tooth structure is cut more aggressively.

Shape: ISO 6360-2 codes the shapes of all dental rotary instruments, and ISO 6360-4 codes the characteristics specific to diamond instruments and diamond-coated discs. A glossary defines the head shape as the outline form of the cutting surface edges, described from the shank to the tip end.

Shank: the shaft section that fits the handpiece may be friction gripping or latch-type in form, and ISO 1797 sets its dimensions and material properties. That standard does not cover tips fixed to the handpiece with a screw.

Discs: diamond discs sit under their own standard, ISO 7711-2, which covers discs used in the dental laboratory for cutting materials such as metals, ceramics, plastics or gypsum and selects five shapes with their dimensions.

How long one lasts: a study notes that no specific literature sets a maximum limit for changing diamond burs during or after a procedure. Published guidance says to consider items difficult to clean, carbide and diamond burs among them, as single-use disposables and discard them after one use.

Sterilizing: where diamonds are reprocessed, dry heat is used for materials that might be damaged by moist heat, and a review names unsaturated chemical vapour as effective for steel instruments such as dental burs.

What it leaves behind: a review notes that grinding with diamond burs can significantly increase the surface roughness of a restoration, which is then reduced by polishing.

Testing: ISO 8325 gives the general test methods for rotary instruments, covering dimensional characteristics, neck strength and surface roughness.