Dentofacial osteotomy is usually performed using oscillating and reciprocating saws, burs, and manual chisels. High speed burs are used without anaesthetic, drilling through enamel or restorations to dentine. Burs are also classified by the type of shank. Dust, dirt, twigs, leaves, burs, and everything else quickly become tangled in the coat. They are burs, sometimes adorned with knobs, wings, or spines. This is a perennial grass which produces is flowers and fruits within spiny burs. The pollinated flowers develop fruits with burs. The roomy toe box is filled with iron spikes, teeth, and burs. The burs are one or 1.5 centimeters long and covered in small hook-like spines. The burs are hard and bear two to four sharp spines, long and broad point-to-point. Female flowers are found at the leaf forks on lower leaves and develop into burs. The seeds are burs, and are very sticky. Seeds dispersal is through the attachment of burs to passing cars, animals and human clothes. Using specific burs through the sleeves the mucosa is removed. Another of the burs is inverted with spikes pointed inward, piercing through a small child.