Permanent body piercings (as opposed to play piercings) are created by creating an opening in the body using a sharp object through the area to be pierced. This can either be done by cutting an opening using a needle (usually a hollow medical needle) or scalpel or by removing tissue, either with a scalpel or a dermal punch.

Contemporary body piercing studios generally take numerous precautions to protect the health of the person being pierced and the piercer. Tools and jewelry are sterilised in autoclaves and non-autoclavable surfaces are cleaned with sterilising agents on a regular basis and between clients. Sterile, single use gloves are worn by the piercer to protect both the piercer and the client.

Standard Needle Method
The standard method in the United States involves making an opening with a hollow medical needle and then following the back of the needle with the initial jewelry to be worn in the piercing. It should be noted that hollow medical needles do not actually remove any flesh, rather, they cut a slit and hold it open in the shape of a circle.

Indwelling Cannula Method
Many European (and other) piercers use a needle containing a cannula (hollow plastic tube placed at the end of the needle). The needle is partly withdrawn, and the jewelery inserted into the other end of the cannula. The cannula is used to pull the jewelry through the newly created opening.

Pierce and Taper
Similar to the standard method, this is a more advanced technique, sometimes used to pierce where large gauge initial jewelry is desired. In this method, after the needle is inserted and the opening is created, a tapered steel bar (usually one gauge larger than that of the needle at the large end) is inserted instead of initial jewelry. Then the jewelry is pushed through the opening, following the tapered bar. The success of this method is dependent on the elasticity of the skin in the area being pierced, the skill of the piercer and the type of piercing being done.

Scalpelling
In this method, a medical scalpel is used to cut a slit, allowing for the insertion of large gauge jewelry. This method is often used in the creation of large gauge ear piercings. Scalpelling can also be used to correct an improper placement on piercings. Scalpelled piercings tend not to shrink or close over time and unwanted piercings may have to be surgically repaired. Scalpelling is most commmonly used on earlobes, but can be used anywhere where large gauge piercings are desired.

Dermal Punching
In this method, a dermal punch is used to remove a circular area of tissue, into which jewelry is placed. It is usually used to remove both skin and cartilige in non-lobe ear piercings, where cartilige must be removed to relieve pressure on the piercing to ensure proper healing and long term viability of the piercing.

Piercing Guns
Piercing guns are commonly used by non-professional body piercers in retail settings to perform ear piercings. These gun-shaped devices force a blunt stud through flesh via mechanical means, causing much greater trauma to the body than any other piercing method. They are often used by untrained personnel and as they cannot be properly sterilised, they place both the operator and the client at much greater risk for infection and the transmission of bloodborne pathogens than any of the methods used by professional body piercers. Most professional body piercers do not use or reccomend using these devices for any purpose. Currently there are efforts by manufacturers to develop improved versions of these devices, for use in other body parts than the earlobe, as well as devices that lessen or eliminate the exposure of client and operators to bloodborne pathogens.

source: wikipedia.org