Dental Lasers: Choosing the Right Equipment for Your Practice

In 1957, physicist Dr. Gordon Gould of Columbia University was the first to coin the acronym "LASER" (light amplification by stimulated emission of radiation). The first working laser device was produced in 1960 by Theodore Maiman (a red beam from ruby crystal). It took nearly another three decades until the US Food and Drug Administration in 1989 approved the first dedicated dental laser, an Nd:YAG (neodymium-doped yttrium aluminum garnet).¹Then, dentistry was off and running.

Lasers have been used for the removal of both hard and soft tissues, with soft-tissue treatment being the primary application. Lasers can be either color or water absorptive. They are used for the micro-removal of tissue, serving largely as an alternative to electrosurgical technology. Procedures for dentistry range from pre-impression uncovering of crown margins, frenectomies, gingivectomies, laser-assisted periodontal treatment, aphthous ulcer treatment, and many more.

Hard-tissue lasers became available to dentists in 1997.² For hard-tissue removal there are three laser wavelengths available on the dental market: 2780 nm, 2940 nm, and 9300 nm. These lasers are of the water absorption type, and they also have soft-tissue treatment capabilities.

Diode lasers, which are color absorptive, are the most commonly used lasers in dental practices. Their relatively affordable pricing is a key factor in their popularity. Diode wavelengths typically range from 808 nm to 1064 nm. These lasers are for soft-tissue applications only. They operate in a variety of modes based on the technology incorporated into them. Some diodes work in the continuous wave mode, in which the diode can be pulsed into 25% or 50% duty cycles.³ A continuous one watt of energy per second can be applied in increments that decrease the applied amount of energy by 25% or 50% per second.

"Super-pulsed" diode lasers are starting to impact the traditional diode laser market. They apply energy in milli- and microseconds. The advantage of these lasers relates to the amount of relaxation time that occurs between pulses of energy applied to the tissue. Time for cooling of the site can help minimize potential collateral tissue damage. Super-pulsed lasers have pre-activated tips that allow for a more consistent energy transfer to the laser tip.

A newer generation of diode laser technology, thermo-optically powered diode lasers, employs an automatic power control that allows for continuous adjustment of power to regulate a constant temperature cutting condition.⁴ The laser pulses in microseconds. Due to the poor coefficient of color absorption, traditional diode lasers require activation of tips, and the energy transfer to the tips can sometimes be inconsistent. A poorly activated tip can penetrate deeply into the tissues, overheating and affecting adjacent structures.⁵

The Nd:YAG laser is a highly efficient tissue cutter and coagulator and is used primarily for laser-assisted periodontal therapies. It offers the benefit of killing black-pigmented bacteria, separating connective tissue from epithelium in the periodontal pocket, and creating a fibrin clot that can contain a variety of growth factors to enhance bone and soft-tissue healing.⁶

Other lasers, of the water absorption type, such as the 10,600-nm carbon dioxide (CO₂), 9300-nm CO₂, 2940-nm erbium-doped yttrium aluminum garnet (Er:YAG), and 2780-nm erbium chromium yttrium scandium gallium garnet (ErCr:YSGG) can also be used for soft-tissue therapies. Both of the aforementioned CO₂ wavelengths are superior coagulators to the erbium wavelengths noted.⁷ All of these lasers are highly efficient at cutting tissue. They all have high absorption coefficients for water and hydroxylapatite,⁸ and they can ablate tissue according to the wavelength used in either super-pulsed or free-running pulsed modes. Both modes afford large amounts of relaxation time in the tissues, thus minimizing potential collateral tissue damage, which is essential for providing high-quality laser therapy.

The dental community generally agrees that lasers that can provide high predictability in the treatment of periodontal disease and peri-implantitis would be of tremendous benefit to practitioners and their patients. Regarding peri-implantitis, selecting the laser wavelength that will have minimal absorption of energy by titanium is critical for minimizing the exposure of potential generated heat to the surrounding bone. The greater the energy of absorption, the greater the effect on the surrounding bone. The 10,600-nm super-pulsed CO₂ laser may provide a predictable method of surface decontamination in the treatment of peri-implantitis.⁹ Finding the correct combination of laser and conventional therapies is vital to improving patient outcomes. More evidence-based research showing predictable results with set protocols will help enable successful utilization of laser therapy in theses areas.

Low-level laser technologies (LLLTs) (ie, red-light technologies) have begun to gain traction and have seen an increase in use in dentistry for both the dentist and hygienist. These technologies are bi-wavelength dynamic, allowing the waves to work synergistically, thus providing effects on lowering inflammation in one mode and offering pain relief in another mode.¹⁰Positive results have been achieved in patients who have oral mucositis as secondary effects of chemo and radiation therapies.¹¹ Delivering high levels of oxygen to these tissues is necessary to resolve these problems. LLLT has also been used for treatment of temporomandibular joint disorder problems.

Looking ahead, practitioners can anticipate the emergence of blue-laser technologies, which are in development for the easy removal of bonded restorations without affecting tooth structure underneath. Special dyes are being developed that will be incorporated into cements. In order to work, all lasers must have a material that absorbs the laser's energy. These chemicals may have absorption potential into the cementum. If this occurs, there may be potential for removal of calculus without affecting the underlying cementum.

Lasers can be valuable when using virtual scanning technologies. Excessive tissue and bleeding can make it difficult to obtain an accurate scan for crown-and-bridge restorations. If manufacturers of scanning equipment are able to package a cost-effective laser with their products, this would greatly benefit clinicians utilizing these technologies.

Education and cost are perhaps the principal keys to the expansion of laser use in dental offices. Regarding education, while a few US dental schools provide rigorous laser training in their curriculums, a large number of young doctors do not experience the use of a laser during their pre-doctoral training years. Hopefully, this may change in the next few years. Regarding cost, receiving appropriate training can be cost-prohibitive to young graduating doctors. The large amounts of debt that many of these graduating doctors incur make the purchasing of expensive equipment such as lasers extremely difficult, and often times such investments are put on the "back burner."

Having convenient access to online training can help enable these young practitioners to gain an introduction to lasers. If they are able to visualize the value lasers provide, they may be more inclined to pursue this mode of treatment. Numerous online programs are available that can help practitioners learn cost effectively. Learning how to use a dental laser and how it can benefit a practice may inspire young dentists to invest in the equipment. Diode lasers offer the most cost-effective route for young doctors to enter into the laser marketplace. Purchasing a diode laser may be the bridge to acquiring a more sophisticated, higher-priced laser later.

A wide variety of dental lasers are available to help practitioners treat patients effectively and with minimal pain or bleeding. Lasers can be both versatile and practical for any dental practice. Regardless of cost, clinicians should target only a laser that fits into their practice dynamics.

Robert Levine, DDS

Director of Laser Dentistry, Arizona School of Dentistry & Oral Health, Mesa, Arizona; President, Global Laser Oral Health, LLC, Scottsdale, Arizona