Learning from clinical phenotypes: Low-dose biophotonics therapies in oral diseases

Medication-Related Osteonecrosis of the Jaw: Successful Medical Management of Complex Maxillary Alveolus with Sinus Involvement

Medication-related osteonecrosis of the jaw (MRONJ) in cancer patients presents a considerable challenge in management. Current management is primarily based on interventions in a limited number of cases assessing a single approach. Medical management typically is reported to include antimicrobial therapy with or without surgery. Advances in the understanding of pathogenesis have led to the investigation of additional medical interventions for early-stage necrosis. We present 3 patients with advanced-stage MRONJ of the maxilla using combined medical modalities including antimicrobial therapy, photobiomodulation therapy, pentoxifylline, vitamin E, and synthetic parathyroid hormone. All patients had a good outcome and avoided surgical intervention. We also report biological and functional imaging that may assist in more effective diagnosis and management of MRONJ. The 3 patients reported suggest that combined medical management should be considered in all cases of MRONJ (including stage III) prior to determining if surgical intervention is required. Functional imaging with a technetium bone scan or positron emission tomography scan correlated with diagnosis and confirmed resolution in patients. We present 3 challenging MRONJ patients that were effectively managed with a combined medical and nonsurgical therapy that demonstrated good clinical outcomes avoiding surgical interventions.

Thermodynamic basis for comparative photobiomodulation dosing with multiple wavelengths to direct odontoblast differentiation

Multiple wavelength devices are now available for photobiomodulation (PBM) treatments, but their dosimetry for individual or combinatorial use remains unclear. The present work investigated the effects of 447, 532, 658, 810, 980 and 1064 nm wavelengths on odontoblast differentiation at 10 mW/cm² using either equal treatment time for conventional fluence (300 seconds for 3 J/cm² ) or varying times to adjust for individual wavelength photon fluence (4.6 p.J/cm² ). Both 447 and 810 nm significantly increased alkaline phosphatase (ALP) activity, while 1064 nm showed reduced ALP activity at 3 J/cm² . However, ALP induction was significantly improved when equivalent photon fluence dosing was used. Other wavelengths did not show significant changes compared to untreated controls. The data suggest that accounting for wavelength-specific photon energy transfer during PBM dosing could improve clinical safety and efficacy.

Effects of Photobiomodulation Therapy with Various Laser Wavelengths on Proliferation of Human Periodontal Ligament Mesenchymal Stem Cells

Several methods have been proposed to enhance the regeneration and healing time in periodontal therapy. Photobiomodulation therapy (PBMT) is a recently suggested novel technique for this purpose. This study aimed to compare the efficacy of PBMT with various laser wavelengths and energy densities on proliferation of human periodontal ligament mesenchymal stem cells (PDLMSCs). The wells containing PDLMSCs were subjected to laser irradiation at 635, 660, 808, and 980 nm wavelengths with 1, 1.5, 2.5 and 4 J/cm² energy densities. Cell proliferation and viability were evaluated after 1, 3, and 5 days with the methyl thiazolyl tetrazolium (MTT) assay and 4,6-diamidino-2-phenylindole (DAPI) staining. No significant difference was observed among the experimental and the control groups on day 1 (P>0.05). On day 3, 808 nm laser at 4 J/cm² energy density and 980 nm laser at all densities had significant differences with control group. On day 5, the control group had significant differences in cell proliferation with 808 nm laser at 2.5 and 4 J/cm² energy densities, and 980 nm laser at all densities. PBMT with 635, 660, 808, and 980 nm wavelengths increased the proliferation of PDLMSCs but the maximum cell viability was prominent after irradiation by 980 nm laser with energy density of 4 J/cm² on day 3.

How can biophotonics help dentistry to avoid or minimize cross infection by SARS-CoV-2?

Biophotonics is defined as the combination of biology and photonics (the physical science of the light). It is a general term for all techniques that deal with the interaction between biological tissues/cells and photons (light). Biophotonics offers a great variety of techniques that can facilitate the early detection of diseases and promote innovative theragnostic approaches. As the COVID-19 infection can be transmitted due to the face-to-face communication, droplets and aerosol inhalation and the exposure to saliva, blood, and other body fluids, as well as the handling of sharp instruments, dental practices are at increased risk of infection. In this paper, a literature review was performed to explore the application of Biophotonics approaches in Dentistry focusing on the COVID-19 pandemic and how they can contribute to avoid or minimize the risks of infection in a dental setting. For this, search-related papers were retrieved from PubMED, Scielo, Google Schoolar, and American Dental Association and Centers for Disease Control and Prevention databases. The body of evidence currently available showed that Biophotonics approaches can reduce microorganism load, decontaminate surfaces, air, tissues, and minimize the generation of aerosol and virus spreading by minimally invasive, time-saving, and alternative techniques in general. However, each clinical situation must be individually evaluated regarding the benefits and drawbacks of these approaches, but always pursuing less-invasive and less aerosol-generating procedures, especially during the COVID-19 pandemic.

Visible blue light inhibits infection and replication of SARS-CoV-2 at doses that are well-tolerated by human respiratory tissue

The delivery of safe, visible wavelengths of light can be an effective, pathogen-agnostic, countermeasure that would expand the current portfolio of SARS-CoV-2 intervention strategies beyond the conventional approaches of vaccine, antibody, and antiviral therapeutics. Employing custom biological light units, that incorporate optically engineered light-emitting diode (LED) arrays, we harnessed monochromatic wavelengths of light for uniform delivery across biological surfaces. We demonstrated that primary 3D human tracheal/bronchial-derived epithelial tissues tolerated high doses of a narrow spectral band of visible light centered at a peak wavelength of 425 nm. We extended these studies to Vero E6 cells to understand how light may influence the viability of a mammalian cell line conventionally used for assaying SARS-CoV-2. The exposure of single-cell monolayers of Vero E6 cells to similar doses of 425 nm blue light resulted in viabilities that were dependent on dose and cell density. Doses of 425 nm blue light that are well-tolerated by Vero E6 cells also inhibited infection and replication of cell-associated SARS-CoV-2 by > 99% 24 h post-infection after a single five-minute light exposure. Moreover, the 425 nm blue light inactivated cell-free betacoronaviruses including SARS-CoV-1, MERS-CoV, and SARS-CoV-2 up to 99.99% in a dose-dependent manner. Importantly, clinically applicable doses of 425 nm blue light dramatically inhibited SARS-CoV-2 infection and replication in primary human 3D tracheal/bronchial tissue. Safe doses of visible light should be considered part of the strategic portfolio for the development of SARS-CoV-2 therapeutic countermeasures to mitigate coronavirus disease 2019 (COVID-19).

Photobiomodulation Dose Parameters in Dentistry: A Systematic Review and Meta-Analysis

Objective: This systematic review and meta-analysis of published randomized controlled trials examines a possible relationship between optical spot size at surface tissue, irradiance, radiant exposure, total energy delivered, operator technique and reported clinical outcomes. Background: Clinical photobiomodulation (PBM) therapy has achieved a high level of evidence-based acceptance in the mitigation of oral mucositis associated with cancer radiotherapy and chemotherapy, and supportive clinical research in relation to orthodontic tooth movement, oral medical conditions, including burning mouth syndrome, xerostomia and lichen planus. Inconsistent outcomes have been reported not withstanding a substantial body of primary supportive research from clinical, in vitro and animal studies. Materials and Methods: PubMed, Cochrane Database of Reviews and Google Scholar search engines were applied to identify human clinical trials of PBM therapy in clinical dentistry. A total of 766 articles between February 2009 and June 2020 were identified and following a full text evaluation, 38 papers with sufficient data to permit analyses are included in this investigation. Results: Following a detailed assessment of potential factors that may have an influence in clinical outcome, a clear trend is apparent associating optical spot size to a positive or negative effect. Furthermore, there is a clear difference in the reported results in relation to total energy applied, delivery techniques and optical parameters, which merits further investigation. Factorial statistical analyses identified an association between smaller optical surface applications and an overall lower level of reported clinical success in treating superficial and deeper targets, and correspondingly sub-surface larger target tissues were found to be more responsive to therapy by use of a larger optical surface spot size. Moreover, use of multiple small diameter probe applications was found to provide inconsistent results. Conclusions: Many factors can confound clinical success including variations in anatomy, site location, clinical condition and subject individuality. To achieve higher levels of predictable outcome, a mature appreciation of these factors, plus an expanded understanding of laser parametry, tissue volume and target depth to deliver an adequate dose within current recommended guidelines, is essential.

Photobiomodulation and Stem Cell Therapy for Temporomandibular Joint Disc Disorders

Background: Temporomandibular disorder (TMD) refers to a group of disorders affecting the temporomandibular joint (TMJ) and its related muscles. The two commonly used treatment modalities for TMD are occlusal splint therapy and relaxation therapy. Neither comprises definitive treatment. Objective: The objective of this review was to report updated information on photobiomodulation and stem cells, as an alternative treatment for the degenerative TMJ disc as a part of TMJ disorders. Materials and methods: With only a few research studies reported till date, this review also proposes the mechanism of laser irradiation on inflammatory mediators to treat TMD. Results: Photobiomodulation of stem cells with and without scaffolds could be used indirectly or directly as modulation of degenerative changes of the TMJ disc. Conclusions: The need for a distinct shift of the research margin in this field of dentistry is evident, specifically regarding the application of photobiomodulation and stem cells for tissue engineering of the TMJ disc.

Nitric Oxide in Dental Pulp Tissue: From Molecular Understanding to Clinical Application in Regenerative Endodontic Procedures

Nitric oxide (NO), which is synthesized by the enzyme NO synthase (NOS), is a versatile endogenous molecule with multiple biological effects on many tissues and organs. In dental pulp tissue, NO has been found to play multifaceted roles in regulating physiological activities, inflammation processes, and tissue repair events, such as cell proliferation, neuronal degeneration, angiogenesis, and odontoblastic differentiation. However, there is a deficiency of detailed discussion on the NO-mediated interactions between inflammation and reparative/regenerative responses in wounded dental pulp tissue, which is a central determinant of ultimate clinical outcomes. Thus, the purpose of this review is to outline the current molecular understanding on the roles of Janus-faced molecule NO in dental pulp physiology, inflammation, and reparative activities. Based on this knowledge, advanced physicochemical techniques designed to manipulate the therapeutic potential of NOS and NO production in endodontic regeneration procedures are further discussed. Impact statement The interaction between inflammation and reparative/regenerative responses is very important for regenerative endodontic procedures, which are biologically based approaches intended to replace damaged tissues. Inside dental pulp tissue, endogenous nitric oxide (NO) is generated mainly by immunocompetent cells and dental pulp cells and mediates not only inflammatory/immune activities but also signaling cascades that regulate tissue repair and reconstruction, indicating its involvement in both tissue destruction and regeneration. Thus, it is feasible that NO acts as one of the indicators and modulators in dental pulp repair or regeneration under physiological and pathological conditions.

The controversial natural history of oral herpes simplex virus type 1 infection

The natural history of oral herpes simplex virus type 1 (HSV-1) infection in the immunocompetent host is complex and rich in controversial phenomena, namely the role of unapparent transmission in primary infection acquisition, the high frequency of asymptomatic primary and recurrent infections, the lack of immunogenicity of HSV-1 internalized in the soma (cell body) of the sensory neurons of the trigeminal ganglion, the lytic activity of HSV-1 in the soma of neurons that is inhibited in the sensory neurons of the trigeminal ganglion and often uncontrolled in the other neurons, the role of keratin in promoting the development of recurrence episodes in immunocompetent hosts, the virus-host Nash equilibrium, the paradoxical HSV-1-seronegative individuals who shed HSV-1 through saliva, the limited efficacy of anti-HSV vaccines, and why the oral route of infection is the least likely to produce severe complications. The natural history of oral HSV-1 infection is also a history of symbiosis between humans and virus that may switch from mutualism to parasitism and vice versa. This balance is typical of microorganisms that are highly coevolved with humans, and its knowledge is essential to oral healthcare providers to perform adequate diagnosis and provide proper individual-based HSV-1 infection therapy.

Polarized Polychromatic Noncoherent Light (Bioptron Light) as Adjunctive Treatment in Chronic Oral Mucosal Pain: A Pilot Study

Objective: Aim of this study was to assess the efficacy of polarized polychromatic noncoherent light (Bioptron light) in the treatment of chronic oral mucosal pain (COMP). Patients and methods: Twenty-two patients affected by COMP were treated with standardized pharmacological protocols in association with Bioptron light (90 W; light wavelength = 480-3400 nm; degree of polarization = 95%; specific power density = 40 mW/cm²; energy density = 2.4 J/cm). The outcome measures were intensity of pain [measured by visual analog scale (VAS) score] and signs reduction (measured by Eisen score) recorded at baseline (t₀), after 4 weeks (t₁), and after 8 weeks (t₂). Signs and symptoms scores were compared with those of a cohort of comparable patients selected from institutional medical record files. Results: Patients in pharmacological treatment associated with Bioptron showed a significant VAS score decrease at t₁ and t₂ (t₀ = 6.9, t₁ = 3.9, t₂ = 1.8, p < 0.05), whereas the patients in exclusive pharmacological treatment showed a significant VAS score improvement only at t₂. Comparing the VAS score at t₁ and t₂ in the two groups, a significant improvement was recorded in patients undergoing Bioptron adjunctive treatment (t₁ = 3.9 vs. 5.9; p < 0.05 and t₂ = 1.8 vs. 3.6; p < 0.05). In both groups Eisen score improved at t₁ and t₂, but in the Bioptron-treated patients the improvement was statistically better at t₁ (1.9 vs. 0.8; p < 0.05) and at t₂ (2.7 vs. 1.4; p < 0.05). Conclusions: In COMP patients, Bioptron use associated with pharmacological treatment allows a better and faster signs and symptoms reduction when compared with the exclusive pharmacological treatment. Further controlled studies are needed to establish the relative and absolute effectiveness of Bioptron in COMP management.