The power source excites the molecules of the gas or crystal. This creates packets of energy called photons. Mirrors are used to direct the photons, which shoot out as a narrow, intense beam of laser light. There are different types of lasers, depending on which gas or crystal is used. In some dental lasers, the mirrors have been replaced with a hollow aluminum tube that reflects the photons.

Because lasers are expensive and take time to learn how to use, many dentists do not own them. But lasers are becoming more popular. Procedures done with a laser generally don't cost any more than those done with a drill (handpiece) or blade. Most laser treatments actually take less time than those done in the traditional way.

Lasers that use erbium in combination with other elements are now the type most commonly used by all dentists. They typically have an air and water stream, like a traditional drill. They can cut teeth, bone and soft tissue. Little or no anesthesia is required. There is usually no pain after surgery.

Diode lasers do not use air and water. They can be used to cut soft tissue or bleach teeth. They also can be used to reduce pain in any muscle or joint. This called low-level laser therapy. When the dentist uses a diode laser for cutting, you will need a topical anesthetic or, in some cases, a shot to numb the area.

Nd:Yag lasers can be used for hard and soft tissue, but do not cut hard tissue as well as erbium lasers. They are therefore used less often.

Biopsy — Lasers often are used to remove tissue so that it can be examined under a microscope. Stitches often aren't needed for a laser biopsy. The area heals on its own.

Removal of lesions (ablation) — Lasers can remove lesions, such as leukoplakia, by destroying thin layers of surface cells. This is generally done after a microsopic diagnosis from a biopsy.

Frenectomy — A frenum is a fold of tissue in the mouth. Frenums are found between the upper two front teeth, under the tongue, and on the sides of the gums. In some people, a frenum is too large. This can interfere with speech or tooth eruption. In a frenectomy, this fold of tissue is cut. A laser frenectomy causes less bleeding than a frenectomy done with a scalpel.

Uncovering impacted teeth — Impacted teeth are trapped in the jawbone. The tooth that is most frequently impacted and requires uncovering, or exposure, is the upper canine. A laser can cut the gum to expose the tooth, particularly if it is under the gum on the roof of the mouth. This will cause much less bleeding.

Gingivectomy — Certain medicines cause severe gum overgrowth. A gingivectomy removes the overgrowth. Using a laser to remove the tissue prevents bleeding. Also, with a laser, the surgeon can sculpt the gum tissue around the teeth so it looks natural.

Fillings —Certain types of lasers can be used to remove tooth decay and prepare teeth. This often can be done without anesthesia. This is particularly useful in treating children. Using a laser also allows the dentist to remove less of the tooth before placing the filling. It cannot be used to remove old silver fillings.

Endodontics — Lasers can be used to sterilize root canals. The laser kills 99.8% of bacteria in the canal. Lasers also can be used for a root surgery called an apicoectomy. The laser is used to cut soft tissue to get to the bone. Then the bone is removed with the laser to expose the root of the tooth.

Treatment of sensitivity — Sensitive teeth can be treated by holding the laser handpiece over the sensitive areas of the tooth. This is usually near the gum line.

Exposing dental implants — Dental implants are special screws. They are put into the jaw to replace missing teeth. Usually, the gum tissue is placed over the implant while it heals. Then it is removed later using a scalpel. Some surgeons elect to use a laser to expose the top of the implant. This also allows crowns, a bridge or a denture to be placed on the implants sooner.

Snoring treatment — Laser-assisted uvulopalatoplasty (LAUP) is used to shorten the uvula. That's the bulb of tissue that hangs down in the back of your throat. It is sometimes the cause of snoring.

Periodontal treatment — Lasers can be used to reduce the depth of "pockets" around the teeth of people with periodontal (gum) disease. The laser kills the bacteria that are inflaming the gums and destroying the bone around the tooth.

Treatment for cold sores (aphthous ulcers) — In people with painful cold sores, a laser can be used to sear the nerve endings. This doesn't make the sores heal faster, but it does relieve pain.

Other uses — Lasers are also used for a wide variety of skin disorders. They are effective in removing vascular and some pigmented lesions. Lasers are also sometimes used for cosmetic skin resurfacing to remove wrinkles.

A key activates the laser. The key is stored separately. This prevents someone from accidentally turning on the laser.

The dentist, assistants and the patient need to wear glasses to protect them from the light of the laser. Clear plastic lenses are fine for carbon dioxide lasers. Special eyewear is needed for other lasers. A sign should be posted on the outside of the room to warn others that the laser is in use.