Understanding Dental Lasers: They’re Not Only for Frenectomies

Fundamentally, in dentistry, infrared laser wavelengths are absorbed differently by the tissues. In summary, 10,600-nanometer (nm) (carbon dioxide [CO₂] laser), or 2,780-nm (erbium, chromium: yttrium-scandium-gallium-garnet [Er,Cr:YSGG] laser) and 2,940-nm (erbium: yttrium-aluminum-garnet [Er:YAG] laser) wavelengths, have a greater absorption by water and hydroxyapatite and therefore can be used for highly water-containing lesions (eg, mucoceles) or dentin ablation, respectively. That is, CO₂ lasers are well-suited for use on lesions containing water, and Er,Cr:YSGG or Er:YAG lasers for dentin ablation.In implant dentistry, CO₂ lasers can be applied for implant surface decontamination, as there is no high risk of overheating.^1,2 In contrast, near-infrared diode (810-nm, 940-nm, 970-nm, 980-nm) or neodymium: yttrium-aluminum-garnet (Nd:YAG) (1,064-nm) lasers are highly absorbed by hemoglobin and pigmented areas (eg, tattoos, black-pigmented bacteria, inflamed tissues) and must be used with caution to avoid complications related to overheating, especially around implants (Figure 1).

The thermal effects of lasers are associated with delayed wound healing without scar-tissue formation^3,4 and lack of bacteriemia risk,⁵ and therefore they have beneficial effects on tissue ablation and soft-tissue peeling and in instances where compromised immunological tissue response is anticipated. CO₂ lasers are widely used for many surgical procedures, especially on the soft tissues, such as soft-tissue tumor removal, pre-prosthetic surgery, frenectomies, drug-induced gingivectomies, and implant decontamination for peri-implantitis therapy, providing excellent hemostasis and minimal risks.^6-8 The erbium family of lasers has been used in periodontology to remove calculus, providing similar outcomes to the use of ultrasonics⁹ and reducing the pathological findings in nonsurgical^10,11 and surgical periodontal therapy.¹²

Diode lasers have been used extensively in dental offices mainly because of their comparatively small, portable size and relatively low pricing. However, research indicates a need for clarification of the requirements for better surgical efficiency to maximize the benefits of this technology and provide better, safer patient care. With the utilization of the correct initiator, significant improvement of concentrated energy at the glass fiber tip (hot tip) can be achieved, with excellent hemostasis and without scar tissue formation or risk of complications.^13,14 Recent studies by the author's team at Stony Brook University focused on the control of complications due to irradiation and showed a high scattering effect when homogenous, highly vascularized oral tissue (ie, bovine tongue) was infiltrated with local anesthetic.¹⁵ The light will be absorbed by the proximal blood vessels and scattered by the high water-containing (anesthetic) concentrated area. This, therefore, demonstrates a need for comprehensive knowledge of laser-tissue interactions, power settings, and differentiation of the different diode lasers based on the absorption characteristics of laser wavelengths and the clinical condition of the irradiated tissue at the histological level.

With regard to diode laser applications, clinicians must consider the differences among the various wavelengths, such as 440-nm, 445-nm, 810-nm, 940-nm, 970-nm, and 980-nm. For instance, evidence shows that the 940-nm diode laser can be used for implant surface decontamination for a longer period without promoting overheating of the implant compared with the 810-nm or 980-nm diode lasers.¹⁶ An 810-nm diode laser can be very dangerous with a pulsed power of 2 watts compared to the 980-nm diode laser and should be used in a lower power setting for safety purposes.^2,17

Diode lasers can be used clinically for ablation (eg, excision, incision) utilizing an initiated tip for most soft-tissue intraoral applications and troughing, but also for removal of inflamed pocket epithelium during periodontal therapy.¹⁸ When clinicians in periodontology intend to provide a deeper tissue penetration to achieve sufficient hemostasis and reduction of periodontal pathogenic bacteria, a non-initiated tip allows decontamination of the connective tissue, leading to bacteria reduction.¹⁹ This photonic source has the benefit of being absorbed by the bacteria with dark color and by the highly vascularized infiltrated granulation tissue, controlling bleeding and improving coagulation and shrinkage of vascularized lesions (eg, hemangiomas) or inflamed tissues (reducing exudation). This has been shown in different studies in periodontology, in which an 810-nm diode laser was utilized for bacteria reduction in pockets²⁰ or in aggressive periodontitis patients,²¹ significantly improving the clinical outcomes. Thus, there has been a significant utilization of diode laser technology and the correct fiber optics in clinical periodontology applications without the use of such drugs as photosensitizers, and this has been applied in photodynamic therapy.²² Previous pilot clinical studies showed similarities in the clinical outcome and antimicrobial effects of photodynamic therapy with the use of a 980-nm diode laser.²³

Low-powered lasers can be used in repetitive doses to reduce pain and stimulate wound healing. Photobiomodulation (PBM) is highly beneficial in the treatment of intraoral lesions in oral mucositis patients. Recent clinical practice guidelines presented the multiple benefits of PBM (eg, pain reduction, lack of side effects) in cancer patients with oral mucositis using the correct irradiation dose and irradiation period to achieve a biological effect and clinical outcome.^24,25 Furthermore, PBM has been noted to directly modulate the potent host immune responses.²⁶

Laser technology can be utilized today in dental practice based on scientific knowledge and evidence and has demonstrated benefits for patients and clinicians alike. The author proposes that lasers have been widely under-utilized in dentistry. As with most dental instruments, there is a need for comprehensive information, research, and clinical training for better understanding and, in this case, to discover the power of light for successful outcomes and enhanced clinical safety.

Georgios E. Romanos, DDS, PhD, Prof Dr med dent

Professor, Diplomate, American Board of Periodontology, Stony Brook University, Stony Brook, New York; Professor, Oral Surgeon, Johann Wolfgang Goethe University, Frankfurt, Germany; President, Lasers and Bio-photonics Scientific Group, International Association for Dental Research