Tweezers with curved tips also exist, sometimes called bent forceps. Most cutaneous bleeding can be controlled with electrocautery, especially bipolar forceps. The invention of surgical forceps is attributed to Stephen Hales. Obstetric forceps or ventouse may be used to facilitate childbirth. For practical reasons the two instruments (forceps and scissors) are available in a sterile kit. Some of these new advances included different types of forceps, sutures, and ligatures. Extraction forceps are commonly used to remove teeth. This is undertaken using long forceps, with 30-cm artery clamps the ideal tool. It may be an alternative to a forceps delivery and caesarean section. The introduction of the obstetrical forceps provided huge advances in the medicalisation of childbirth. Some disposable forceps are made of plastic. The tooth concerned can be removed using a combination of luxators, elevators and extraction forceps. The pelvic curve of the blades is identical to all other forceps. The baby should not be preterm, previously exposed to scalp sampling or failed forceps delivery. In an emergency it is possible to remove staples with a pair of artery forceps.