Understanding Dental Lasers: They’re Not Only for Frenectomies
Georgios E. Romanos, DDS, PhD, Prof Dr med dent
Often, clinicians consider lasers in dentistry only as a tool for doing frenectomies. Unfortunately, despite the dental laser having more than 30 years of clinical application, many practitioners and educators may lack an extensive understanding of this valuable instrument. This article highlights the scientific basis and indications for the use of lasers in dentistry.
Laser-Tissue Interactions
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).
Soft-Tissue Ablation
The thermal effects of lasers are associated with delayed wound healing without scar-tissue formation3,4 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 nonsurgical10,11 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
Pain Reduction and Photobiomodulation
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
Conclusion
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.
About the Author
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
References
1. Geminiani A, Caton JG, Romanos GE. Temperature increase during CO(2) and Er:YAG irradiation on implant surfaces. Implant Dent. 2011;20(5):379-382.
2. Geminiani A, Caton JG, Romanos GE. Temperature change during non-contact diode laser irradiation of implant surfaces. Lasers Med Sci. 2012;27(2):339-342.
3. Romanos GE, Pelekanos S, Strub JR. Effects of Nd:YAG laser on wound healing processes: clinical and immunohistochemical findings in rat skin. Lasers Surg Med. 1995;16(4):368-379.
4. Romanos GE, Siar CH, Ng K, Toh CG. A preliminary study of healing of superpulsed carbon dioxide laser incisions in the hard palate of monkeys. Lasers Surg Med. 1999;24(5):368-374.
5. Kaminer R, Liebow C, Margarone JE 3rd, Zambon JJ. Bacteremia following laser and conventional surgery in hamsters. J Oral Maxillofac Surg. 1990;48(1):45-48.
6. Romanos GE. Current concepts in the use of lasers in periodontal and implant dentistry. J Indian Soc Periodontol. 2015;19(5):490-494.
7. Romanos GE. Advanced Laser Surgery in Dentistry. Hoboken, NJ: Wiley-Blackwell; 2021.
8. Romanos GE, Nentwig GH. Regenerative therapy of deep peri-implant infrabony defects after CO2 laser implant surface decontamination. Int J Periodontics Restorative Dent. 2008;28(3):245-255.
9. Sculean A, Schwarz F, Berakdar M, et al. Periodontal treatment with an Er:YAG laser compared to ultrasonic instrumentation: a pilot study. J Periodontol. 2004;75(7):966-973.
10. Schwarz F, Sculean A, Georg T, Reich E. Periodontal treatment with an Er:YAG laser compared to scaling and root planing. A controlled clinical study. J Periodontol. 2001;72(3):361-367.
11. Schwarz F, Sculean A, Berakdar M, et al. Clinical evaluation of an Er:YAG laser combined with scaling and root planing for non-surgical periodontal treatment. A controlled, prospective clinical study. J Clin Periodontol. 2003;30(1):26-34.
12. Sculean A, Schwarz F, Berakdar M, et al. Healing of intrabony defects following surgical treatment with or without an Er:YAG laser. J Clin Periodontol. 2004;31(8):604-608.
13. Romanos GE. Diode laser soft tissue surgery: advancements aimed at consistent cutting, improved clinical outcomes. Compend Contin Educ Dent. 2013;34(10):752-757.
14. Romanos GE, Sacks D, Montanaro N, et al. Effect of initiators on thermal changes in soft tissues using a diode laser. Photomed Laser Surg. 2018;36(7):386-390.
15. Romanos GE, Tedesco RW, Malhotra U, et al. Diode laser light scattering and temperature changes due to anesthesia injection in bovine tongue mucosa. Photobiomodul Photomed Laser Surg. 2021;39(9):587-592.
16. Romanos GE, Motwani SV, Montanaro NJ, et al. Photothermal effects of defocused initiated versus noninitiated diode implant irradiation. Photobiomudul Photomed Laser Surg. 2019;37(6):356-361.
17. Valente NA, Mang T, Hatton M, et al. Effects of two diode lasers with and without photosensitization on contaminated implant surfaces: an ex vivo study. Photomed Laser Surg. 2017;35(7):347-356.
18. Romanos GE, Henze M, Banihashemi S, et al. Removal of epithelium in periodontal pockets following diode (980 nm) laser application in the animal model: an in vitro study. Photomed Laser Surg. 2004;22(3):177-183.
19. Romanos GE, Estrin NE, Lesniewski A, et al. Penetration depth of initiated and non-initiated diode lasers in bovine gingiva. Appl Sci. 2022;12(24):12771.
20. Moritz A, Gutknecht N, Doerbudak O, et al. Bacterial reduction in periodontal pockets through irradiation with a diode laser: a pilot study. J Clin Laser Med Surg. 1997;15(1):33-37.
21. Kamma JJ, Vasdekis VGS, Romanos GE. The effect of diode laser (980 nm) treatment on aggressive periodontitis: evaluation of microbial and clinical parameters. Photomed Laser Surg. 2009;27(1):11-19.
22. Takasaki AA, Aoki A, Mizutani K, et al. Application of antimicrobial photodynamic therapy in periodontal and peri-implant diseases. Periodontol 2000. 2009;51:109-140.
23. Romanos GE, Brink B. Photodynamic therapy in periodontal therapy: microbiological observations from a private practice. Gen Dent. 2010;58(2):e68-e73.
24. Zadik Y,Arany PR, Rodrigues Fregnani E, et al; Mucositis Study Group of the Multinational Association of Supportive Care in Cancer/International Society of Oral Oncology. Systematic review of photobiomodulation for the management of oral mucositis in cancer patients and clinical practice guidelines. Support Care Cancer. 2019;27(10):3969-3983.
25. Miranda-Silva W, Gomes-Silva W, Zadik Y, et al; Mucositis Study Group of the Multinational Association of Supportive Care in Cancer/International Society of Oral Oncology. MASCC/ISOO clinical practice guidelines for the management of mucositis: sub-analysis of current interventions for the management of oral mucositis in pediatric cancer patients. Support Care Cancer. 2021;29(7):3539-3562.
26. Tang E, Khan I, Andreana S, Arany PR. Laser-activated transforming growth factor-ß1 induces human ß-defensin 2: implications for laser therapies for periodontitis and peri-implantitis. J Periodontal Res. 2017;52(3):360-367.
