Photodynamic Therapy in Periodontal and Peri-Implant Diseases - A New Insight Volume 57- Issue 2

G Kamala, R Divya Lakshmi, K B Roshni and Neetha J Shetty*

• Department of Periodontology, Manipal College of Dental Sciences, Mangalore, Manipal Academy of Higher Education, India

Received: June 24, 2024; Published: July 03, 2024

*Corresponding author: Neetha J Shetty, Department of Periodontology, Manipal College of Dental Sciences, Mangalore, Manipal Academy of Higher Education, Manipal, India

DOI: 10.26717/BJSTR.2024.57.008990

Abstract PDF

Periimplantitis is a biofilm-mediated disease, hence an antimicrobial approach is essential to prevent its further progress. The microbial colony that causes peri implantitis is highly diverse, it is crucial to eliminate the biofilm surrounding the implant during the treatment. Various non-surgical and surgical methods, which include flap debridement, laser decontamination, regenerative methods, and many others, are available to treat periimplantitis. Additionally, in the past, local and systemic chemical antimicrobial agents were utilised to improve mechanical therapy approaches, which has its drawbacks. So, Nonsurgical modalities were looked into the depth for its management. This review article aims to evaluate the effects of photodynamic therapy and thiocyanate as a photosensitizing dye used to treat periimplantitis. Antimicrobial photodynamic therapy is used for the eradication of pathogenic microbial cells and involves the light excitation of dyes in the presence of oxygen, yielding reactive oxygen species including the hydroxyl radical and singlet oxygen. To chemically enhance Photodynamic therapy (PDT) by the formation of longer-lived radical species, thiocyanate was used to enhance the light mediated killing of gram positive and gram-negative organisms. Thiocyanate enhances PDT killing in a concentration dependent manner of Streptococcus aureus and Escherichia coli. This review highlights photodynamic therapy features and its photosensitizing enhancing strategies which yield in antimicrobial outcomes.

Keywords: Thiocyanate; Low Level Energy Laser; Photosensitizers; Photodynamic Therapy; Periimplantitis

Peri-implant infections are of two types, Peri-implantitis and Peri-implant mucositis. The bacteria that cause these infections are present in the oral biofilm [1]. Peri implant mucositis is defined as “an inflammatory process around a dental implant without loss of supporting bone beyond biological bone remodelling” [2]. Periimplantitis is defined as “the inflammation of supporting tissues of dental implants in association with bone loss, which will result in the progressive destruction of bone around the implant, if left untreated” [3]. Generally, peri-implant mucositis is defined by the following symptoms and signs: irritation of the mucosa without loss of alveolar bone, whereas peri-implantitis is defined by the loss of supporting bone along with mucosal inflammation [4]. It is noticeable under the microscope that peri implantitis is characterized by an increase in inflammatory cells infiltrating around implants, which can be seen apical to the pocket epithelium the microbial colony that causes peri implantitis is quite complex and heterogenous [4].

Microorganisms responsible for periimplantitis include anaerobic gram negative, fusiform pathogens and aerobic gram-positive pathogens. Hence, the removal of biofilm from the surface of implant as well as the immediate surrounding area is of utmost importance in the case of periimplantitis [5]. There are various approaches to treating periimplantitis, including both non-surgical and surgical, including flap debridement, laser decontamination, regenerative approach, and many more [2], in the past, systemic and local chemical antimicrobial agents were employed to treat periimplantitis, to decrease the load of periodontal pathogens in comparison to mechanical techniques. Additionally, these treatments were designed to enhance the efficacy of mechanical therapeutic techniques. The use of antimicrobial agents, however has its disadvantages. This includes an increase in the number of resistant microorganisms, use of different antibiotics that are specific to each microbe, a decrease in therapeutic effects in immunosuppressed patients and an increased occurrence of unfavourable reactions.

Consequently, alternative techniques for treating periimplantitis have been recommended as a more suitable solution [3]. Lasers can be used to disinfect implant surfaces and help treat the inflammatory process surrounding the implant in the presence of photosensitizers. This is known as photodynamic therapy. Lasers used in dentistry includes different types of wavelengths that are delivered in continuous, pulsed or continuous wavelengths. The table attached below gives a brief description about various lasers used in dentistry (Table 1) [6].

Table 1: Lasers of different wavelength used in clinical dentistry.

Photodynamic Therapy

The most commonly used lasers are diode, erbium lasers, CO2 lasers because of their haemostatic properties, bactericidal effects and selective calculus ablation [7]. In today’s rapidly growing technological world, the application of photodynamic therapy (PDT) as a means of antimicrobial treatment has become increasingly important. The increase in PDT as an alternative approach to treating a variety of periodontal infections is due to the sudden increase in the number of antibiotic-resistant microorganisms. These organisms living in biofilms are up to 1,000 times more resistant to antimicrobials [8]. Photodynamic therapy is a non-invasive therapeutic treatment used to treat a variety of infections caused by bacteria, fungi and viruses. PDT has been defined as “an oxygen dependent reaction that occurs by action of low energy single frequency light and activation of photoactive materials/photosensitizers” [9]. Photodynamic therapy involves the use of a low-power diode laser in conjunction with photosensitization compounds (Figure 1) [7,10].

Figure 1

Photosensitizers

A sensitizing dye is used to kill the microorganism under the action of visible light. Many dyes used for PDT have inherent antibacterial effects, but the photodynamic bactericide effect is only produced during irradiation. The subgingival and supragingival plaque biofilm on the surface of the tooth are easily accessible to rinse with the dye and activate them by light [11]. In recent decades, low-intensity lasers with photosensitizers have been increased to reduce or eliminate bacteria, also known as aPDT (antimicrobial photodynamic therapy) [5]. Specific photosensitizers used in aPDT are methylene blue (MB), toluidine blue, erythrosine, and hematoporphyrin, and are safe to use. When combined with light, methylene blue is shown to be effective in killing C. albicans, Helicobacter pylori, and influenza viruses. Methylene blue and toluidine blue are known to be highly effective photosensitizers for inactivating periodontal pathogens present in biofilms. Two types of lasers exist in the dental field: high and low power laser irradiation. High-power laser irradiation does not activate the photoactive dyes, as even relatively weak irradiation has a high bactericidal effect. Thus, the light sources used in photodynamic therapy are - argon lasers (488-514nm), gallium-aluminium-arsenide diode lasers (630-690nm) and helium-neon lasers (633nm) [10]. In 2013, Methylene blue (MB) (10 μM) was supplemented with a thiocyanate (SCN- ) salt to test whether it improved responses against Staphylococcus aureus and Escherichia coli. Within the solution, MB-SCN produced cyanide ions and sulphite equally.

Each salt when individually added enhanced the aPDT process. The final results showed that thiocyanate enhanced aPDT killing of both bacterial strains in a light dependent and concentration gradient manner [12]. A study conducted to evaluate the efficacy of thiocyanates as photosensitizers to treat peri-implantitis found that thiocyanates can increase photodynamic inactivation of S. aureus in a concentration-dependent manner. was observed. It has also been suggested that thiocyanate can achieve PDT enhancement compared to azide [13]. The use of low-power lasers has been stated to have added beneficial consequences on surrounding cells and tissues, in addition favouring periodontal healing due to potential bioregulatory consequences inclusive of cell proliferation and stimulation [10].

Mode of Action

Photosensitizing and light individually cannot cause an effective cytotoxic effect on cells. Photosensitizing dyes are usually applied to the affected area through interstitial injection, aerosol delivery or topical application. The photosensitizer is activated by the light that has specific wavelength. This therapy turned out to be a major evolutionary as it was possible to use uniform intensive light with the right low energy to trigger a photodynamic response [10]. The photosensitizing molecules binds to the appropriate cells and when light with specific wavelength is used along with oxygen, it undergoes a transition from basal state of low energy to excited state (Figure 2) [7,12].

Figure 2

Periodontal and peri-implant diseases are orchestrated by bacterial challenge and a compromised host response. The treatment of such conditions should thus involve mechanical debridement combined with adjunctive therapies which are capable of minimising the bacterial load and also modulating the local host response. A constant demand for non-invasive yet effective clinical procedures have thus led to the advent and application of Photodynamic Therapy in the field of dentistry. Among the various other agents recently investigated, thiocyanate, a nontoxic inorganic salt, has been shown to potentiate the mechanism of PDT mediated by Methylene blue by imparting antimicrobial properties. Not only that, it has also shown to enhance wound healing of tissues. However, further in-depth clinical studies are necessary to support this review of literature and more Randomised controlled trials should be done to compare the use of thiocyanate and other salts which could enhance the functioning of the photosensitizer used in photodynamic therapy. Nevertheless, LASERs are here to stay and this therapy offers a promising approach which can substitute for chemotherapy in the treatment of periodontal and peri implant diseases.

1. Vohra F, Al-Rifaiy MQ, Lillywhite G, Abu Hassan MI, Javed F, et al. (2014) Efficacy of Mechanical Debridement with Adjunct Antimicrobial Photodynamic Therapy for The Management of Peri-Implant Diseases: A Systematic Review. Photochemical and Photobiological Sciences 13(8): 1160-1168.
2. Suárez-López del Amo F, Yu SH, Wang HL (2016) Non-Surgical Therapy for Peri-Implant Diseases: A Systematic Review. J Oral Maxillofac Res 7(3): e13.
3. Birang E, Talebi Ardekani MR, Rajabzadeh M, Sarmadi G, Birang R, et al. (2017) Evaluation of Effectiveness of Photodynamic Therapy with Low-Level Diode Laser in Nonsurgical Treatment of Peri-Implantitis. J Lasers Med Sci 8(3): 136-142.
4. JervøeStorm PM, Jepsen S, Worthington Hv, Needleman I, Eberhard J, et al. (2015) Adjunctive antimicrobial photodynamic therapy for treating periodontal and peri-implant diseases. Cochrane Database of Systematic Reviews 2015(6).
5. Tonin MH, Brites FC, Mariano JR, Freitas KMS, Ortiz MAL, et al. (2022) Low-Level Laser and Antimicrobial Photodynamic Therapy Reduce Peri-implantitis-related Microorganisms Grown in Vitro. Eur J Dent 16(1): 161-166.
6. Cobb CM (2006) Lasers in Periodontics: A Review of the Literature. J Periodontol 77(4): 545-564.
7. Romeo U, Nardi GM, Libotte F, Sabatini S, Palaia G, et al. (2016) The Antimicrobial Photodynamic Therapy in the Treatment of Peri-Implantitis. Int J Dent.
8. Al-Ahmad A, Bucher M, Anderson AC, Tennert C, Hellwig E, et al. (2015) Antimicrobial Photoinactivation Using Visible Light Plus Water-Filtered Infrared-A (Vis + Wira) Alters in Situ Oral Biofilms. PLoS One 10(7): e0132107.
9. Rakašević D, Lazić Z, Rakonjac B, Soldatović I, Janković S, et al. (2016) Efficiency of Photodynamic Therapy in the Treatment of Peri-Implantitis - A Three-Month Randomized Controlled Clinical Trial. Srp Arh Celok Lek 144(9-10): 478-484.
10. Takasaki AA, Aoki A, Mizutani K, Schwarz F, Sculean A, et al. (2009) Application of Antimicrobial Photodynamic Therapy in Periodontal and Peri-Implant Diseases. Periodontol 51(1): 109-140.
11. Meisel P, Kocher T (2005) Photodynamic Therapy for Periodontal Diseases: State of The Art. Journal of Photochemistry and Photobiology B Biology 79(2): 159-170.
12. Diogo P, Faustino MFA, Neves GMPMS, Palma PJ, Baptista IP, et al. (2019) An Insight into Advanced Approaches for Photosensitizer Optimization in Endodontics—A Critical Review. J Funct Biomater 10(4): 44.
13. St Denis TG, Vecchio D, Zadlo A, Rineh A, Sadasivam M, et al. (2013) Thiocyanate Potentiates Antimicrobial Photodynamic Therapy: In Situ Generation of the Sulfur Trioxide Radical Anion by Singlet Oxygen. Free Radic Biol Med 65: 800-810.