By Dara Rosenberg, D.D.S., M.S., M.P.H.

Columbia University College of Dental Medicine

Dental lasers have been used in the United States for almost 20 years. During that time they have been further refined. Research has taught us a great deal about their applications and effects. The question is, have dental lasers finally reached a stage where evidence shows that they are reliable, safe and a better alternative than conventional treatments?

I believe the answer is yes.

Why Use Lasers?

Clinical studies have been performed around the world for more than 25 years. The most recent studies have clearly shown that using lasers for many dental procedures:

• Reduces the need for local anesthesia
• Improves healing
• Allows dentists to remove less tissue in some procedures
• Improves outcomes
• Increases patient acceptance of dental treatment

As a founding member of the World Clinical Laser Institute (WCLI), I have seen many advances in recent years. Lasers have been further refined and their uses expanded. The WCLI has focused on:

• Training dentists
• Safety and regulation
• Research and innovation
• Education through the written word and presentations

WCLI and other dental laser organizations have enabled dentists to discuss their laser experiences through symposiums held around the world. These groups also have been concerned with standards for testing and levels of expertise.

How Do Lasers Work?

A discussion of lasers requires some background information. The first laser was developed in 1960. It had the same three basic parts as modern lasers:

• An energy source (power supply)
• A solid, gas or liquid substance in a container
• A space that has mirrors on both ends

The type of laser depends upon the substance (medium) that is used. Common mediums include carbon dioxide, argon, ruby and sapphire. The newer lasers, particularly ones used by dentists, combine mediums. They may include chromium, erbium and gallium. Each substance produces a specific wavelength of light.

Laser light is not like normal light. Laser light contains only one unique wavelength (energy frequency). Laser light is an organized beam. The beam is very thin and concentrated. It travels in only one direction.

Lasers can be found in everything from CD players to supermarket bar code readers to high-speed metal cutting machines. They are commonly used in tattoo removal and eye surgery (LASIK).

Each wavelength interacts with cells differently. Some wavelengths can cut teeth (hard tissue) better than others. Some can cut soft tissue (such as gums). Others can stimulate cell activity. It has taken years to determine the best wavelength, power and other variables of the laser light so that it can be used in dentistry.

How Are Lasers Used?

The Food and Drug Administration (FDA) approves lasers for sale and use in the United States. The FDA has approved dental lasers for use for specific procedures. These include:

• Removal of decay — Lasers cut the tooth without generating heat or vibrations. Therefore the process produces little or no pain. This can allow the dentist to remove decay and fill a cavity without anesthesia (a numbing shot).

• Preparing teeth for a filling or a crown — A laser can prepare teeth without anesthesia (a numbing shot). Lasers also allow dentists to remove less of the tooth. Lasers don't cause tiny fractures of the tooth enamel the way a drill does. Cutting is more precise without the heat and vibration of the conventional drill.

• Treatment of root canals — Lasers can clean and sterilize root canals. Lasers have been shown to kill 99.8% of the bacteria in the root canal. The more bacteria are destroyed in the canal, the more successful a root canal is likely to be.

• Treating very sensitive teeth — Lasers can reduce or eliminate the sensitivity.

• A variety of other soft and hard tissue removal — Using a laser lets a dentist cut soft tissue very precisely without anesthesia and bleeding.

Lasers improve healing. They decrease pain after a procedure. They can be used to kill bacteria that cause periodontal disease, without making the surviving bacteria harder to kill (resistant). They also do not create adverse drug or allergic reactions.

Most recently, the FDA approved the first diode laser for low-level laser therapy. Diode lasers have shorter wavelengths in the infrared spectrum of light. They are small and use low power.

All forms of light affect living organisms. The low-level lasers have been shown to alter the cell membrane and increase certain cell activities. This causes very positive responses in the exposed area:

• Less inflammation, swelling and pain
• Muscle relaxation
• Improved healing
• Improved immune system response

In dentistry, diode lasers are used to cut soft tissue or remove inflamed areas in the gum pockets around teeth. They also have been used to reduce swelling and pain after extractions, and to treat facial pain.

Advantages and Disadvantages

There are many advantages to the use of lasers within dentistry. For example, do you have difficulty getting numb for dental procedures? A dental laser may be able to help. People have been found to need less anesthesia during most procedures that use a laser.

Using a laser has been found to decrease pain after an extraction. Dental lasers even can be used to eliminate pain from canker sores. Another advantage is that a laser-treated tooth is more resistant to acid and decay.

There are some limitations to the use of the laser. For example:

• Dentists need to learn how to use each laser. Understanding the settings and the tissue reaction takes some time.
• Old silver fillings are difficult to remove with the laser.
• Some procedures, such as cutting down a tooth for a crown, may still take slightly longer to perform with the laser.
• Lasers require the use of protective eyewear for the dental staff as well as the patient.

Lasers are one of the most significant new major technologies in dentistry. They will continue to advance dental treatments and patient acceptance in the future. Their use can improve outcomes in surgery and other procedures. They also can increase patient satisfaction. So, perhaps it is time to consider having dental laser treatment. It's one of the most advanced ways to promote gentler, more thorough dentistry.