Lasers and light devices: an integral tool in contemporary clinical dentistry - Guest Editorial

The year 2015 was celebrated as the International Year of Light and Light-based Technologies 2015 or International Year of Light 2015 by the United Nations to raise awareness of the tremendous accomplishments of light sciences (Nations, 2015).

A quick glance at the impact of light and its applications showcases its tremendous impact on every facet of our modern lives, from high-speed optical communications, rapid manufacturing, and cosmological explorations. There are a few other examples of technological innovations that have profoundly impacted modern civilization and the progress of humankind.

Light technologies have revolutionized biology and medicine using high-resolution sub-cellular imaging with optical microscopes, and ophthalmological vision correction is considered routine daily practices.

Unsurprisingly, clinical dentistry has benefitted significantly from these innovations in optics and photonics technologies (Arany, 2016).

These innovations can be broadly categorized into improved illumination, emerging optical diagnostic techniques, theranostics, manufacturing, surgical procedures, and non-surgical treatments.

This commentary provides a brief description and fundamental premise of these advances, and the audience is encouraged to explore more detailed resources on the vast fields these represent.

Working in a restricted anatomical space with active water spray and saliva compounded by sharp, high-speed rotary instruments presents dentists with unique operative challenges.

Illumination of the workspace has been an omnipresent challenge. Innovations in optical technologies have enabled superior chair lighting, magnifying loops with focused LED illumination, and self-illuminating instruments, among others (Figure 1).

These innovations have improved accurate evaluations and operative procedures and serve as an essential trainee and patient education-motivation tool when combined with digital imaging. The advent of digital dentistry has made optical scanners a routine clinical tool. The reducing costs, compact footprint, ease of use, and accessibility to a post-imaging laboratory digital workflow have heralded modern digital dentistry.

Besides digital scanning, the use of fluorescence-based diagnostics for caries, periodontal disease, and pre-malignancies has made excellent recent progress (Gimenez et al., 2013; Park et al., 2020; Simonato et al., 2019).

Newer techniques like optical coherence tomography (OCT), photoacoustic imaging (PAI), Surface-Enhanced Raman Spectroscopy (SERS), and terahertz imaging are already in use in medicine. These modalities are in advanced stages of development for clinical deployment in dentistry within the next decade. These tomographic and spectroscopic techniques only offer non-invasive, real-time, and repeated assessments along with compositional changes that provide diagnostic and prognostic value (Galler et al., 2019; Hernández‐Cedillo et al., 2019; Kamburoglu et al., 2019; Katkar and Geha, 2018).

A recent example is using SERS to detect microleakage and marginal deterioration of restorations to determine clinical replacements (Spencer et al., 2021).

These unprecedented insights into pathophysiological changes in oral-dental tissues prompt newer disease classifications and clinical interventional strategies, often with molecular precision.

However, another significant impact of these innovations is addressing the critical question on what exactly and how extensively to treat clinically. The field of theranostics, a portmanteau (blend) of the words therapy and diagnostics, has several classic examples in modern medicine, especially in oncology. The presence of a specific malignant mutation offers a molecular target for specific interventions.

New approaches in dentistry are exploring these concepts where the optical diagnostic technique that detects caries in Enamel or Dentin using a light-based spectroscopic technique is coupled to a treatment laser that can then precisely ablate this lesion (Figure 2) (Chan and Fried, 2012; 2017; Tom et al., 2015).

Another area using this concept is oncology, where laser ablation of tumors can instantly analyze the plume (aerosol) to determine if further ablation is necessary at the margins (Moon et al., 2018; Teng et al., 2020; Wang et al., 2018).

Light-based composites have predominated restorative dental procedures, providing ease of material manipulation and long working times. Improved curing light power and newer wavelengths, especially with higher power LEDs and lasers, are increasing the degree and depth of curing, contributing to improved long-term material performance (Kouros et al., 2020).

3D printing laser technologies with both additive (laser sintering) and subtractive (milling) approaches are enabling rapid, cost-effective manufacturing (Figure 3). A significant advantage of the additive manufacturing approach is the reduced material wastage, increased complexity, and higher resolution attainable (Zhang et al., 2019).

These biomaterial applications for prosthetic and restorative work have expanded to include polymers, ceramics, and metals with increasing emphasis on individual patient customization (Venet et al., 2017).

The most common image of laser use in dentistry is its surgical application for soft tissue surgeries. Tremendous improvement in laser diode technologies has created a clinical renaissance with dental lasers' accessible and affordable availability.

These advances in laser technologies have also extended to both gas (e.g., carbon dioxide) and solid-state (e.g., Er:YAG, Er,Cr:YSGG) that have brought more compact and better-controlled lasers for all tissue, hard and soft tissue use.

In fact, the growth of the dental laser market has been noted to be over 5% in the coming years, making it one of the most sought-after dental technologies.

The improvements in our understanding of laser-biological tissue interactions have enabled a more rationalized approach for its clinical use. The use of high-power lasers ensures rapid tissue vaporization (above 100 C) that is effectively employed for surgical incisions, excisions, and curettage.

The area around these high-power surgical laser sites is exposed to lower energy, resulting in protein denaturation and coagulation. This is a significant advantage of using lasers in surgical procedures to attain a blood-less operative field. Post-laser procedures, these tissues heal remarkably well despite their rather non-pristine (brownish-yellow) appearance.

An extension of this surgical photothermal approach targets biofilms or pigmented bacteria (Pourhajibagher et al., 2016). This approach has been termed photodisinfection, photo-assisted disinfection, or simply laser hygiene. While this approach is effective clinically, it inadvertently results in adjacent tissue thermal damage.

An exogenous dye or photosensitizer is often employed to improve the safety and specificity of these responses. This process is called photo-activated disinfection or, most appropriately, antimicrobial photodynamic therapy (aPDT). This light-mediated technique requires lower power than surgical procedures and is a non-thermal, redox-mediated process that selectively destroys microbes.

Another use of this specific PDT technology is directed against tumors via cancer antigen-tagged photosensitizers (nanoparticles or liposomes) (Tampa et al., 2019).

Finally, another non-surgical, non-thermal approach is termed Photobiomodulation (PBM) (Hamblin, 2016). This treatment uses low-dose light treatments in the visible and near-infrared wavelengths to alleviate pain and inflammation or promote tissue healing and regeneration. This therapy is often confused with PDT, where the primary goal is the destruction of the target, while PBM responses are primarily inhibitory or stimulatory.

Recent progress in our understanding of the precise molecular mechanisms and biomarkers enables optimal PBM clinical protocol recommendations leading to safe and effective clinical outcomes.

A major recent milestone in this field relevant to clinical dentistry was the recommendation of the Multinational Association of Supportive Care in Cancer and the International Society of Oral oncology recommending the use of PBM treatment for the management of oncotherapy (radiation, chemotherapy, and transplants) associated oral mucositis (Logan et al., 2020). The broad applications of PBM span several dental specialties, from temporomandibular joint disorders to peri-implantitis (Nadershah et al., 2019; Tang et al., 2017).

Recent work from our group demonstrated the ability of PBM to induce human β-Defensin 2 inducing an antimicrobial host response (Tang et al., 2017). This PBM-host response can act synergistically with routine or laser surgical curettage and disinfection procedures (Figure 4).

In summary, light and laser technologies offer significant utility in improving clinical care in current dentistry. A laser is a tool, and it is prudent to emphasize that attention must be given to the nuances of device parameters and their biological interactions to ensure optimal patient safety and clinical effectiveness.

It would not be surprising to expect future dental chairs to include integrated laser or light devices capable of multitasking such as diagnosis, treatment, and theranostics to usher in the ear of patient-centered precision individual care.

References

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Authors: 

Philip Sales

I was born and raised in Chicago, Illinois. I received my Masters in Biology at the University at Buffalo in the Arany lab and completed my Bachelors in Pre-Health at Benedictine University. My interests are in oral biology, 3D printing, and digital dentistry. My hobbies over the years include sculpting, painting, and graphic design. These creative outlets have helped me to develop my knowledge of CAD/CAM and apply it to the dental field. My goal is to utilize my knowledge of digital design and new technologies, to showcase its power and impact when it comes to treating medically complex cases in dentistry.

 

Yousef Alhorebi

I am from San'aa, Yemen and recently graduated with my BS degree from University at Buffalo. I am currently a research assistant in the Arany lab and work on the use of photobiomodulation therapy for peri-implant disease management. I aspire to be a clinical dentist and use this technology in my daily practice. The publication of laser technology in the dentistry field has inspired me to continue this study even after my dental schooling. I am always striving and working hard to learn and educate through research.

 

Bhavneet K. Chawla

I was raised in Punjab, India where I did my schooling and finished my Bachelor in Dental Surgery. I moved to the US to do Masters in Oral Sciences at SUNY, Buffalo. My research during my MS revolved around proton pump inhibitors in periodontal disease. Currently, I am volunteering as a Research Assistant in Arany’s lab where I am working on a project that involves lasers and photobiomodulation. I am looking forward to beginning my journey in the International Dentist Program at SUNY, Buffalo in May, 2022.

 

Praveen Arany

I received my dental degree at KIDS, Belgaum, and completed a joint PhD-Residency program at Harvard University as a Harvard Presidential Scholar and two certificates in clinical translational research from Harvard Medical School and the National Institute of Health. Following postdoctoral training at the Indian Institute of Sciences, National Cancer Institute, and Harvard School of Engineering & Applied Sciences, I served as an Assistant Clinical Investigator at NIDCR, NIH, Bethesda, and am currently an Assistant Professor in departments of Oral Biology, Surgery, and Biomedical Engineering. I have served in various key leadership positions, have over 125 publications, serve on editor and reviewer. I have served as the past-president of the North-American and World Association for Photobiomodulation Therapy (WALT). My primary research focuses on the molecular mechanisms and clinical translation of Photobiomodulation therapy.