Light-emitting diode irradiation promotes donor site wound healing of the free gingival graft

Protective Effect of Red Light-Emitting Diode against UV-B Radiation-Induced Skin Damage in SKH:HR-2 Hairless Mice

In this in vivo study on hairless mice, we examined the effects of light-emitting diode (LED) treatment applied prior to ultraviolet B (UVB) irradiation. We found that pre-treating with LED improved skin morphological and histopathological conditions compared to those only exposed to UVB irradiation. In our study, histological evaluation of collagen and elastic fibers after LED treatment prior to UVB irradiation showed that this pretreatment significantly enhanced the quality of fibers, which were otherwise poor in density and irregularly arranged due to UV exposure alone. This suggests that LED treatment promotes collagen and elastin production, leading to improved skin properties. Additionally, we observed an increase in Claudin-1 expression and a reduction in nuclear factor-erythroid 2-related factor 2 (Nrf-2) and heme-oxygenase 1 (HO-1) expression within the LED-treated skin tissues, suggesting that LED therapy may modulate key skin barrier proteins and oxidative stress markers. These results demonstrate that pretreatment with LED light can enhance the skin's resistance to UVB-induced damage by modulating gene regulation associated with skin protection. Further investigations are needed to explore the broader biological effects of LED therapy on other tissues such as blood vessels. This study underscores the potential of LED therapy as a non-invasive approach to enhance skin repair and counteract the effects of photoaging caused by UV exposure.

Effect of GaAlAs 940 nm Photobiomodulation on palatal wound healing after free gingival graft surgery: a split mouth randomized controlled clinical trial

Background

The aim of this study was to evaluate the effects of photobiomodulation (PBM) on wound healing, pain, and discomfort at free gingival graft (FGG) donor sites.

Methods

Sixteen patients in need of bilateral FGG were selected for this randomized, controlled, triple-blinded, and split mouth clinical trial. The FGG donor sites in test group were treated with LLLT GaAlAs 940 nm, 5 J/cm² immediately after surgery and every other day within the following ten days. The control group received sham irradiation. Remaining Wound Area (RWA), Epithelialization and color match were evaluated on the day of surgery and 7, 14, 21, 28, and 60 days after surgery. A questionnaire was administered to measure pain and bleeding in the first ten days after surgery.

Results

RWA was significantly smaller in the test than control group on the days 7 (p < 0.001) and 14 (p = 0.048) after the surgery. Bleeding was higher in the test group than in the control group on the day of surgery (p = 0.046). Pain and discomfort at the palatal donor site, however, had no significant difference between laser and control group during 11 days after the surgery (p > 0.05), nor did the Color match scores on the 28th and 60th days after the surgery (p > 0.05).

Conclusions

It can be concluded that PBM enhances FGG donor site wound healing one and two weeks after the surgery.

Trial registration

IRCT2017092036203N2, registered 01.11.2017.

Effects of ozonated olive oil and photobiomodulation using diode laser on gingival depigmented wound: A randomized clinical study

Objective:

Photobiomodulation (PBM) using diode laser is regarded an effective modality for the repair of tissues and control of pain. Ozone, owing to its biocompatibility, healing, and antimicrobial properties, is used in dentistry as well. This study was carried to clinically compare and evaluate the healing of gingival depigmented wounds using ozonated oil and PBM.

Materials and Methods:

A laser depigmentation procedure was conducted on seven patients exhibiting bilateral upper and lower gingival melanin hyperpigmentation, followed by the application of ozonated oil (Group 1) and laser PBM (Group 2). The clinical parameters are taken namely Visual Analog Scale and Healing Index (HI), were evaluated on the 3^rd, 7^th, and 15^th day.

Results:

Statistical analysis showed better HI in Group I as compared to Group II on the 3^rd day, but it was comparable in both groups on the 7^th and 15^th day.

Conclusion:

The application of ozonated oil was found to be more efficacious in promoting the initial healing of wound in comparison to PBM. Both ozonated oil and PBM also showed the same capabilities in reduction of the postoperative pain.

Fluorescent light energy modulates healing in skin grafted mouse model

Skin grafting is often the only treatment for skin trauma when large areas of tissue are affected. This surgical intervention damages the deeper dermal layers of the skin with implications for wound healing and a risk of scar development. Photobiomodulation (PBM) therapy modulates biological processes in different tissues, with a positive effect on many cell types and pathways essential for wound healing. This study investigated the effect of fluorescent light energy (FLE) therapy, a novel type of PBM, on healing after skin grafting in a dermal fibrotic mouse model. Split-thickness human skin grafts were transplanted onto full-thickness excisional wounds on nude mice. Treated wounds were monitored, and excised xenografts were examined to assess healing and pathophysiological processes essential for developing chronic wounds or scarring. Results demonstrated that FLE treatment initially accelerated re-epithelialization and rete ridge formation, while later reduced neovascularization, collagen deposition, myofibroblast and mast cell accumulation, and connective tissue growth factor expression. While there was no visible difference in gross morphology, we found that FLE treatment promoted a balanced collagen remodeling. Collectively, these findings suggest that FLE has a conceivable effect at balancing healing after skin grafting, which reduces the risk of infections, chronic wound development, and fibrotic scarring.

Autophagy upregulation may explain inhibition of oral carcinoma in situ by photobiomodulation in vitro

There is currently no clear understanding on the pathways involved in the process of cell inhibition by photobiomodulation (PBM). The present study evaluated the influence of PBM on the expression of autophagy markers in vitro in an in situ model of oral carcinoma. Oral squamous cell carcinoma (Cal27) and stromal fibroblasts (FG) cultures were used. The independent variables were 'cell type' (FG and CAL27) 'culture condition' (monocultures or co-cultures) and PBM (placebo and 36 J/cm²). The cultures were irradiated from a red LED source for mRNA expression and protein expression analyses. The autophagy markers evaluated were Beclin-1, LC3B and p62 as well as adjuvant markers (BAX Bcl-2, VEGF, CD105, CD34, PRDX1, PRDX4 and GRP78). The Cal27 cells upregulated the autophagy markers upon exposure to PBM both at the mRNA and protein expression levels, providing evidence to explain malignant cell inhibition by PBM.

Erbium, Chromium:Yttrium-Scandium-Gallium-Garnet Laser for Root Conditioning and Reduction of Postoperative Morbidity in the Treatment of Gingival Recession Defects: A Randomized Controlled Clinical Trial

Objective: This clinical trial evaluates the effect of erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) root surface biomodification and laser harvesting of de-epithelialized gingival graft (DGG) on root coverage clinical outcomes and postoperative morbidity, and compares this to the conventional blade-harvested DGG method without Er,Cr:YSGG root surface biomodification in treatment of Miller's class I, II gingival recessions (GR). Background: The application of laser technology to enhance tooth root coverage clinical outcomes as well as the impact of laser on postoperative morbidity after harvesting autogenous soft tissue grafts requires further research. Methods: This study is a randomized, single-blinded controlled trial, including 24 volunteers with isolated GR defects. They were allocated into three treatment groups to receive one of the following three interventions: blade-harvested DGG (control group: B-DGG); Er,Cr:YSGG-harvested DGG and root surface biomodified [test 1 group: L-laser-harvested DGG (L-DGG)/laser root biomodification (LRB)]; and B-DGG and Er,Cr:YSGG root surface biomodification (test 2 group: B-DGG/LRB). Clinical and radiographic parameters were recorded at baseline (1 week before surgery) and 3, 6, and 9 months postoperatively. Results: Root coverage did not show a statistically significant difference between control and test groups. Statistically significant differences were found for Visual Analog Scale on the day of surgery and day 3 and 4 postoperatively, as well as pain medication on the day of surgery favoring the L-DGG group. Conclusions: The use of Er,Cr:YSGG laser in root surface biomodification improved root coverage outcomes at 9 months. Even these changes were not statistically significant from the control group; the L-DGG technique was associated with decreased postoperative morbidity in the palatal donor site.

Blue LED causes autophagic cell death in human osteosarcoma by increasing ROS generation and dephosphorylating EGFR

Osteosarcoma (OS) is the most common primary malignant bone tumour in adolescence. Lately, light‐emitting diodes (LED)‐based therapy has emerged as a new promising approach for several diseases. However, it remains unknown in human OS. Here, we found that the blue LED irradiation significantly suppressed the proliferation, migration and invasion of human OS cells, while we observed blue LED irradiation increased ROS production through increased NADPH oxidase enzymes NOX2 and NOX4, as well as decreased Catalase (CAT) expression levels. Furthermore, we revealed blue LED irradiation‐induced autophagy characterized by alterations in autophagy protein markers including Beclin‐1, LC3‐II/LC3‐I and P62. Moreover, we demonstrated an enhanced autophagic flux. The blockage of autophagy displayed a remarkable attenuation of anti‐tumour activities of blue LED irradiation. Next, ROS scavenger N‐acetyl‐L‐cysteine (NAC) and NOX inhibitor diphenyleneiodonium (DPI) blocked suppression of OS cell growth, indicating that ROS accumulation might play an essential role in blue LED‐induced autophagic OS cell death. Additionally, we observed blue LED irradiation decreased EGFR activation (phosphorylation), which in turn led to Beclin‐1 release and subsequent autophagy activation in OS cells. Analysis of EGFR colocalization with Beclin‐1 and EGFR‐immunoprecipitation (IP) assay further revealed the decreased interaction of EGFR and Beclin‐1 upon blue LED irradiation in OS cells. In addition, Beclin‐1 down‐regulation abolished the effects of blue LED irradiation on OS cells. Collectively, we concluded that blue LED irradiation exhibited anti‐tumour effects on OS by triggering ROS and EGFR/Beclin‐1‐mediated autophagy signalling pathway, representing a potential approach for human OS treatment.

Comparison of diode laser - Oral tissue interaction to different wavelengths. In vitro study of porcine periodontal pockets and oral mucosa

Background

The aim of this in vitro study was to evaluate the effect of diode lasers at different wavelengths and power settings in handmade incisions in periodontal pockets and in oral mucosa of porcine tissue considering thermal damage, necrosis and the affected area of the soft tissue.

Material and Methods

Combining the following laser wavelengths, 445nm, 532nm (KTP), 810nm, 980nm, 1064nm and 1470nm, and a power range from 0.5W to 2.0W in a continuous wave mode (CW), we made handmade incisions in porcine periodontal pockets and oral mucosa. After histological processing, we measured the area of ​​lost tissue, the area of ​​thermal damage and the area of ​​necrosis. Then, we performed ANOVA to evaluate the difference between groups and two-way ANOVA to identify the influence of the laser-type variables and the power on the results.

Results

We applied an ANOVA test to evaluate the results, where statistical analysis showed clear differences between the 1470nm and 810nm laser groups that refer to thermal damage and necrosis in the periodontal pocket surface. Regarding the oral mucosa surface, the 1064nm laser showed differences in the analysis of lost tissue. According to the applied power, all the variables we studied (lost tissue area, area of thermal damage and necrosis) showed higher values when using a power of 2.0W instead of 0.5W.

Conclusions

According to our results, the 810nm diode laser for oral soft-tissue biopsy using power ranges between 0.5W and 2W would be the best choice to avoid thermal damage in peri-incisional margins.

Key words:Laser surgery, soft tissue, diode laser, KTP laser, thermal damage, necrosis.

Photobiomodulation in Periodontology and Implant Dentistry: Part 1

(Part 2 of this article can be located at www.liebertpub.com/doi/10.1089/photob.2019.4731.) Objective: Finding evidence-based treatment strategies for low-level light therapy (LLLT) and the correct incorporation of these treatment methods in the clinical practice of periodontics. Background: Photobiomodulation has been shown to have biostimulatory, anti-inflammatory and analgesic effects that can be beneficial in periodontal and dental implant treatment procedures. Methods: In this review we have addressed some clinical questions regarding the potential clinical application of low-level light irradiation and its photobiomodulatory effects in periodontology and implantology. The literature was searched for in vivo (animal or clinical) articles written in English in four electronic databases of PubMed, Scopus, Google Scholar, and Cochrane Library until April 2019. Only studies with low irradiation doses without any thermal effects used only for their photobiomodulatory purposes were included. Results: We were able to find relevant studies for all of our questions, and positive effects for the application of light therapy were reported in most of the studies. However, there is still great deal of heterogeneity in terms of study designs and most importantly in light irradiation devices and the parameters used. Owing to this issue it was not possible to reach specific evidence-based irradiation protocols for the questions addressed in this review. Conclusions: Based on our search results, an obvious positive effect of LLLT on stimulation of healing of periodontal soft and hard tissues and reduction of inflammation can be seen. Future well-designed randomized control studies with the same irradiation settings and systematic reviews evaluating the studies found on the questions mentioned are necessary to reach evidence-based recommendations.

The Clinical Evaluation of the Effects of Low-Level Laser Therapy on the Donor and Recipient Sites of the Free Gingival Graft: A Case Series

Introduction: Free gingival grafting is among the most foreseeing procedures for increasing the zone of keratinized attached gingiva and enhancing soft tissue around the teeth and dental implants. Nowadays low-level laser therapy (LLLT) is a promising approach in providing patients with more pleasing results in terms of esthetics and comfort. This study aims to investigate the effects of LLLT on gingival recessions treated with free gingival graft (FGG). Methods: This case series was conducted on 12 individuals requiring a bilateral gingival graft in the mandibular region. There was a 30-day interval between the two operations. The test side was selected randomly and irradiated by a low-level laser (LLL) just before surgery. The patients did not know which side was irradiated. LLLT was applied to the donors' as well as recipients' site immediately after the operation and 48 hours later. The patients were instructed to record their post-operative pain in a visual analogue scale (VAS) 3 and 24 hours and 7 days after the surgical procedure. The clinical photographs were taken immediately and 30 days after surgical treatment were graded by three experienced periodontists for color matching to adjacent tissues. Results: Ten individuals could finish the study. The test group presented significantly better shade matching and wound healing at the palatal donor site on days 7, 14 and 21. There was a significant reduction in post-operative pain after 24 hours (P = 0.007). No statistically significant difference was found between both groups in terms of clinical periodontal indices. Conclusion: LLLT could reduce post-operative pain 24 hours after surgical treatment. Furthermore, the application of LLLT could improve the donors' site healing and the recipients' site color matching.

Effects of Laser Photobiomodulation and Ozone Therapy on Palatal Epithelial Wound Healing and Patient Morbidity

OBJECTIVE

The aim of this study was to compare the effects of laser photobiomodulation (PBM) and topical ozone therapy on the reepithelialization of palatal donor site wounds through clinical assessment and computer-aided image analysis and to assess the patient morbidity following free gingival graft (FGG) surgeries.

MATERIAL AND METHODS

Thirty-six patients requiring FGG were randomly allocated into three groups: laser group (n = 12), ozone group (n = 12), and control group (n = 12). Epithelialization was evaluated by applying 3% hydrogen peroxide (H₂O₂) to the wound area and also measured by using digital image analysis (ImageJ). Bland-Altman plots were used for assessing agreement between H₂O₂ and ImageJ measurements. Parameters in relation to patient morbidity were assessed by using visual analog scale (VAS) on the first 3, 7, 14, and 30 days postoperatively.

RESULTS

At day 14, statistically significant smaller wounds were observed with digital image analysis in the ozone group as compared with the control group (p = 0.034). However, intergroup comparison of the remaining wound area evaluated by the clinician using the H₂O₂ method did not reveal any significant differences (p > 0.05). Nonetheless, according to Bland-Altman analysis, the lower and upper limits showed a moderate agreement between the two measurement methods. The mean VAS sores exhibiting postoperative discomfort was observed to be significantly higher in the control group compared with the laser group (p = 0.002) and ozone group (p < 0.001) at day 7.

CONCLUSIONS

Adjunctive ozone therapy could have a significantly beneficial effect on the acceleration of palatal wound healing following FGG procedures. Both PBM and ozone treatment modalities reduced postoperative discomfort as compared with spontaneous healing.

Effectiveness of laser adjunctive therapy for surgical treatment of gingival recession with flap graft techniques: a systematic review and meta-analysis

Various flap graft techniques in the treatment of gingival recession have already been reported in the literatures for root coverage. Laser therapy has effects of ablative, hemostatic, and decontamination. Therefore, we performed a meta-analysis of randomized controlled trials (RCTs) to compare the efficacy of flap surgery combined with laser with surgery alone for treating gingival recession. The studies were searched from PubMed, Embase, Web of science, and the Cochrane Central Register of Controlled Trials by two reviewers up to August 2017. The quality of RCTs was assessed by Cochrane Handbook. Data were extracted from studies and analyzed by Review Manager 5.3. 95% confidence interval (CI) and risk ratio (RR) were calculated for dichotomous data. Seven RCTs with 173 patients and 296 teeth were included in the meta-analysis. We found no statistically significant differences between two groups in GRD (gingival recession depth) (P = 0.21), GRW (gingival recession width) (P = 0.92), RES (root esthetic score) (P = 0.21), and CRC (complete root coverage) (P = 0.09). Statistically significant differences were found between two groups in the WKT (width of keratinized tissue) (P < 0.0001) and 1-year follow-up of PD (probing depth) (P = 0.03) and CAL (clinical attachment level) (P < 0.00001). The meta-analysis found that surgery with laser therapy provided clinical advantages in terms of WKT and 1-year follow-up of PD and CAL. However, flap graft associated with laser did not offer additional benefit to root coverage and esthetics in treating gingival recession. More long-term studies are required to assess these parameters.

Fabrication of Multi-Layered Lidocaine and Epinephrine-Eluting PLGA/Collagen Nanofibers: In Vitro and In Vivo Study

This study developed multi-layered lidocaine- and epinephrine-eluting biodegradable poly[(d,l)-lactide-co-glyco lide] (PLGA)/collagen nanofibers. An electrospinning technique was employed to fabricate the multi-layer biodegradable drug-eluting nanofibers. After fabrication, the nanofibrous membranes were characterized. The drug release characteristics were also investigated. In addition, the in vivo efficacy of nanofibers for pain relief and hemostasis in palatal oral wounds of rabbits were evaluated. Histological examinations were also completed. The experimental results suggested that all nanofibers exhibited good biocompatibility and eluted effective levels of lidocaine and epinephrine at the initial stages of wound recovery.

Effect of Photobiomodulation on Transforming Growth Factor-β1, Platelet-Derived Growth Factor-BB, and Interleukin-8 Release in Palatal Wounds After Free Gingival Graft Harvesting: A Randomized Clinical Study

Objective: This study evaluated the impact of photobiomodulation (PBM) on the healing of the donor palatal area following free gingival graft (FGG) harvesting by examining changes in transforming growth factor (TGF)-β₁, platelet-derived growth factor (PDGF)-BB, and interleukin (IL)-8 levels in palatal wound fluid (PWF). Material and methods: Thirty patients were selected and randomly assigned to receive PBM (laser group) or PBM sham (sham group) in the palatine area after FGG harvesting. A neodymium-doped yttrium aluminum garnet (Nd:YAG) laser (1064 nm) was applied to the test sites immediately after surgery and every 24 h thereafter for 4 days. PWF was collected on Days 7 and 12, and PWF TGF-β₁, PDGF-BB, and IL-8 levels were analyzed by enzyme-linked immunosorbent assays (ELISA). Results: PWF TGF-β₁, PDGF-BB, and IL-8 levels were significantly lower on Day 12 than on Day 7 for both groups. PWF TGF-β₁, PDGF-BB, and IL-8 levels of the laser group were significantly higher than those of sham group on Day 7 (p < 0.05). PWF TGF-β₁ levels were also significantly higher in laser group than in the sham group on Day 12; however, differences in PDGF-BB and IL-8 levels between groups on Day 12 were statistically nonsignificant. Conclusions: Observed increases in PWF TGF-β₁, PDGF-BB, and IL-8 levels suggest that PBM may accelerate wound healing by stimulating production of selected mediators.

The dark art of light measurement: accurate radiometry for low-level light therapy

Lasers and light-emitting diodes are used for a range of biomedical applications with many studies reporting their beneficial effects. However, three main concerns exist regarding much of the low-level light therapy (LLLT) or photobiomodulation literature; (1) incomplete, inaccurate and unverified irradiation parameters, (2) miscalculation of ‘dose,’ and (3) the misuse of appropriate light property terminology. The aim of this systematic review was to assess where, and to what extent, these inadequacies exist and to provide an overview of ‘best practice’ in light measurement methods and importance of correct light measurement. A review of recent relevant literature was performed in PubMed using the terms LLLT and photobiomodulation (March 2014–March 2015) to investigate the contemporary information available in LLLT and photobiomodulation literature in terms of reporting light properties and irradiation parameters. A total of 74 articles formed the basis of this systematic review. Although most articles reported beneficial effects following LLLT, the majority contained no information in terms of how light was measured (73 %) and relied on manufacturer-stated values. For all papers reviewed, missing information for specific light parameters included wavelength (3 %), light source type (8 %), power (41 %), pulse frequency (52 %), beam area (40 %), irradiance (43 %), exposure time (16 %), radiant energy (74 %) and fluence (16 %). Frequent use of incorrect terminology was also observed within the reviewed literature. A poor understanding of photophysics is evident as a significant number of papers neglected to report or misreported important radiometric data. These errors affect repeatability and reliability of studies shared between scientists, manufacturers and clinicians and could degrade efficacy of patient treatments. Researchers need a physicist or appropriately skilled engineer on the team, and manuscript reviewers should reject papers that do not report beam measurement methods and all ten key parameters: wavelength, power, irradiation time, beam area (at the skin or culture surface; this is not necessarily the same size as the aperture), radiant energy, radiant exposure, pulse parameters, number of treatments, interval between treatments and anatomical location. Inclusion of these parameters will improve the information available to compare and contrast study outcomes and improve repeatability, reliability of studies.

Diode laser for harvesting de-epithelialized palatal graft in the treatment of gingival recession defects: a randomized clinical trial

AIMS

The aim of present randomized controlled clinical study was to evaluate the effects of the use of diode laser for graft harvesting and palatal wound irradiation on post-operative morbidity and root coverage outcomes after a coronally advanced flap (CAF) with de-epithelialized gingival grafts (DGG).

METHODS

Fifty-two patients with isolated recessions were treated. The CTG resulted from the de-epithelialization of a free gingival graft (FGG) with blade (control group:DGG-B) or diode laser (DL) (test group:DGG-L). The DL was used to de-epithelialize the outer part of the FGG and photo-biostimulate the palatal wound area. Post-operative morbidity was evaluated by using Oral Health-related Quality of Life (OHQoL) and Visual Analogue Scale-discomfort (VAS). Root coverage outcomes were also evaluated 6 months after operation.

RESULTS

Statistically significant differences were found for OHQoL (p = 0.0001) and VAS (p = 0.0001) at the 7th day post-operatively favouring test sites. Root coverage results did not show a statistically significant difference.

CONCLUSIONS

While both techniques were effective with regard to root coverage at 6 months, the DGG-L technique decreased post-operative morbidity associated with palatal donor-site surgery.