Effect of low-level laser therapy on wound healing and patients' response after scalpel gingivectomy: A randomized clinical split-mouth study

Relevant markers for overactive bladder laser therapy: nitric oxide and urinary nerve growth factor

To investigate the potential of nitric oxide (NO) and urinary nerve growth factor (NGF) as indicators of therapeutic outcomes in overactive bladder (OAB) patients undergoing low-level laser therapy (LLLT) via a prospective randomized controlled trial. Fifty OAB patients participated in the study and were subjected to LLLT using 650-nm laser irradiation. The study employed a prospective randomized controlled trial design. Nitric oxide and urine NGF levels were assessed before and after the LLLT intervention to evaluate their correlation with therapeutic outcomes. The study provided evidence supporting the effectiveness of LLLT as a treatment modality for OAB. Analysis of NO and urine NGF levels revealed significant changes following LLLT intervention suggesting their potential as biomarkers for assessing therapeutic response in OAB patients. These biomarkers hold promise for aiding clinicians in evaluating treatment response and personalizing therapy approaches for OAB patients. This study highlights the utility of LLLT in managing OAB and underscores the importance of exploring biomarkers such as nitric oxide and urinary nerve growth factor to enhance treatment efficacy assessment. The findings suggest that NO and urine NGF levels may serve as valuable indicators of therapeutic outcomes in OAB patients undergoing LLLT. Further research is warranted to elucidate the underlying mechanisms and optimize the clinical application of LLLT in OAB management.

Effect of Open Flap Debridement with and without LLLT in Patients with Periodontitis on Wound Healing, GCF ALP Levels, and Clinical Parameters

AIM

The tenet of the study is to evaluate the efficacy of low-level laser therapy (LLLT) as an adjunct to surgical periodontal therapy [open flap debridement (OFD)] on clinical parameters, gingival crevicular fluid (GCF) alkaline phosphatase (ALP) levels in GCF and wound healing.

MATERIALS AND METHODS

Thirty subjects afflicted with chronic periodontitis showing evidence of horizontal bone loss on the radiograph, pocket probing depth (PPD) between 4 and 7 mm, and ≥20 natural teeth present in the oral cavity were included in the study. In every patient, OFD+LLLT was done in one quadrant and OFD in another was performed. The clinical parameters were assessed at baseline, 3 and 6 months visits while the GCF sample was collected at baseline visit and 6 months recall. Wound healing indices were recorded 1-week post-op surgery for each group.

RESULTS

The results showed an evident improvement in all the clinical parameters [pocket probing depth, gingival index (GI), plaque index (PI), and CAL] from baseline-6 months values; however, no statistically significant difference was seen on the intergroup comparison. Wound healing was statistically significantly superior in the OFD + LLLT group in comparison to the OFD group, indicating a positive effect of lasers on healing. Gingival crevicular fluid ALP levels in the two groups decreased after 6 months and a statistically significant reduction in the laser group indicated an anti-inflammatory effect.

CONCLUSION

The results clearly indicated the efficacy of lasers in terms of acceleration of wound healing and control of inflammation.

CLINICAL SIGNIFICANCE

Lasers as an adjunct to surgical periodontal therapy evidently have an anti-inflammatory effect (decrease in GCF ALP levels) as well as accelerate the wound healing process. How to cite this article: Gupta R, Arora SA, Gupta G, et al. Effect of Open Flap Debridement with and without LLLT in Patients with Periodontitis on Wound Healing, GCF ALP Levels, and Clinical Parameters. J Contemp Dent Pract 2024;25(12):1148-1155.

Effectiveness of low-level laser therapy in reducing pain score and healing time of recurrent aphthous stomatitis: a systematic review and meta-analysis

BACKGROUND

Recurrent aphthous stomatitis (RAS) is a common chronic inflammatory oral disease that negatively impacts the quality of life. Current therapies aim to reduce pain and healing process yet challenges such as rapid loss due to salivary flushing in topical drugs and adverse effects due to prolonged use of systemic medications require further notice. Low-level laser therapy is reported with immediate pain relief and faster healing thus preserving the potential for optimal treatment modalities. This review critically analyses and summarizes the effectiveness of LLLT in reducing pain scores and healing time of RAS.

METHODS

A systematic search was conducted in ScienceDirect, PubMed, and Scopus using keywords of low-level laser therapy, photo-biomodulation therapy, and recurrent aphthous stomatitis. RCTs between 1967 to June 2022, presenting characteristics of the laser and reporting pain score and/or healing time of RAS after irradiation were included. Animal studies and recurrent aphthous ulcers with a history of systemic conditions were excluded. Studies were critically appraised using the RoB 2 tool. A meta-analysis was performed using inverse variance random effects.

RESULTS

Fourteen trials with a total of 664 patients were included. Reduced pain was reported in 13 studies, while shortened healing time was presented in 4. The pooling of two studies after CO2 irradiation demonstrated faster healing time compared to placebo (MD - 3.72; 95% CI - 4.18, - 3.25).

CONCLUSION

Pain score and healing time of RAS were reduced after irradiation with LLLT. RoB resulted in "some concerns" urging well-designed RCTs with larger samples to further assess each laser application for comparison.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42022355737.

Gingival Zenith Correction by Laser Gingivectomy

A healthy gingival structure showcases a knife-edged gingival margin, firmly adherent to the tooth surface, accompanied by a cone-shaped or pointed interdental papilla, mirroring the lowest point in the gingival margin, termed the gingival zenith. Tooth transposition denotes an anomaly in tooth positioning, commonly involving the canine and the first maxillary premolar. It represents a form of ectopic eruption, wherein two adjacent teeth interchange positions within the same quadrant of the dental arch. Laser wavelengths are utilized for precise incision of gingival tissues to address restorative, cosmetic, and periodontal needs. Post-operatively, rapid healing and diminished discomfort are frequently observed, often eliminating the necessity for periodontal packing or sutures. Gingivectomy is the accepted modality for the establishment of esthetics in situations with abnormal gingival contour. This study highlights the use of contemporary technology namely a 940 nm diode laser for correction of gingival zenith to achieve optimal esthetics post orthodontic treatment.

A systematic review of trends in photobiomodulation in dentistry between 2018 and 2022: advances and investigative agenda

Background

Photobiomodulation (PBM) involves laser therapy utilized in medical sciences to modulate biological processes acting as a palliative and immune response-enhancing treatment. This study conducts a comprehensive bibliometric analysis to explore current trends in PBM-related scientific production, encompassing publications, citations, impact, keywords and clusters. Additionally, it aims to predict future research trends in this domain.

Methods

The data for this quantitative and qualitative bibliometric analysis were obtained from 608 scientific documents retrieved in November 2022, with 123 sourced from Web of Science and 485 from Scopus, Utilizing Excel, the data was processed in Excel to extract essencial information. Productivity and impact were evaluated for eligibility, and VOSviewer aided in determining associativity for the bibliometric analysis.

Results

The findings of this study demostrate that the scientific production related to PBM adheres to a growth power law, exhibiting characteristics of both exponential and linear phases. Notably, recent research trends emphasize critical concepts such as laser therapy, orthodontics, and dental pulp stem cells. Particularly significant is the burgeoning interest in utilizing PBM within dentistry as a complementary alternative to existing protocols.

Conclusions

PBM stands as a promising laser therapy within medical applications. Through a detailed bibliometric analysis, this study underscores the increasing significance of PBM, especially within the realm of dental treatments. These insights offer a glimpse into the evolving landscape of PBM research and provide valuable guidance for potential future directions of study.

Efficacy of hyaluronic acid gel and photobiomodulation therapy on wound healing after surgical gingivectomy: a randomized controlled clinical trial

BACKGROUND

Surgical gingivectomy can be considered the gold standard treatment for gingival enlargement. The healing of wound site after gingivectomy occurs slowly by secondary intention. To accelerate the wound healing process, several studies have been conducted evaluating the effect of various treatment modalities. Photobiomodulation therapy (PBMT) was proposed to provide minimally invasive and painless treatment as well as to decrease discomfort of the patient following the surgical process. Another factor that is expected to improve the healing after surgery is topical application of chemotherapeutic agents such as Hyaluronic acid (HA). This study aims to assess the effect of topically applied HA gel after PBMT on the healing of wound site after surgical gingivectomy.

METHODS

This randomized controlled clinical trial included twenty-six surgical gingivectomy wound sites, equally divided into two groups, Group-I (test group): the surgical sites after gingivectomy were irradiated with a diode laser (980 nm, 0.2 W) then covered by 2% HA gel loaded in a special custom-made soft transparent tissue guard appliance for each patient. Group II (control group): the surgical sites were irradiated with a diode laser (980 nm, 0.2 W) only. Wound healing was assessed subjectively by Landry healing index on the 3rd, 7th, 14th and 21st days after surgery, and pain perception was assessed by the patients using visual analog scale (VAS) throughout the 21 days of the follow up period. Comparisons between the two study groups were performed using Mann-Whitney U test, while comparisons between different time points were performed using Friedman test. Significance was inferred at p value < 0.05.

RESULTS

By the end of the follow-up period, surgical sites of the test group showed excellent healing compared to the control group. There were no significant differences in VAS scores between both groups (p > 0.05).

CONCLUSIONS

Application of 2% HA gel as an adjunctive to PBMT was found to have significant clinical effects and higher power of repair among test group when compared to that achieved by PBMT alone in control group.

TRIAL REGISTRATION

This study was retrospectively registered on ClinicalTrials.gov and first posted on 28th of March 2023 with an identifier number: NCT05787912.

Efficacy of Low-Level Laser Therapy in Wound Healing and Pain Reduction After Gingivectomy: A Systematic Review and Meta-analysis

Introduction: Complete healing of a gingivectomy wound usually takes between one and two months. To speed up this process, different topical medications have been reported. In addition, there are different studies assessing the efficacy of low-level laser therapy (LLLT) in terms of wound healing and pain relief subsequent to gingivectomy, yielding inconsistent outcomes. In the present study, we systematically reviewed the existing evidence in the literature to resolve the given conflicts. Methods: We searched for the studies published from inception to 1 April 2023 in Embase, PubMed, and Scopus databases without language limitation by the use of appropriate keywords. We included randomized or non-randomized clinical trial studies that appraised the efficacy of LLLT in pain reduction and wound healing in adult patients who underwent gingivectomy. We pooled the continuous data concerning the pain visual analogue scale and the healing index extracted from the individual studies to provide a standardized mean difference (SMD) with a 95% confidence interval (CI), using a random-effects model. Results: Out of 188 sources initially captured from the database search, six studies were ultimately included. Regarding wound healing, the LLLT group exhibited a significantly higher mean value of the healing index compared to the control group on days 3 (SMD, 0.93; 95% CI, 0.39 to 1.47) and 7 (SMD, 1.03; 95% CI, 0.49 to 1.57) post-surgery. Also, significant differences were noted in the postoperative pain reduction between the two groups on days 3 (SMD, -2.00; 95% CI, -2.48 to -1.51) and 7 (SMD, -2.44; 95% CI, -4.66 to -0.22) post-surgery. Conclusion: According to the present systematic review, LLLT could potentially be an efficient adjunctive treatment after gingivectomy for wound healing acceleration and patient pain alleviation.

Comparison of Pulsed and Continuous Wave Diode Laser at 940 nm on the Viability and Migration of Gingival Fibroblasts

Gingival fibroblasts have critical roles in oral wound healing. Photobiomodulation (PBM) has been shown to promote mucosal healing and is now recommended for managing oncotherapy-associated oral mucositis. This study examined the effects of the emission mode of a 940 nm diode laser on the viability and migration of human gingival fibroblasts. Cells were cultured in a routine growth media and treated with PBM (average power 0.1 W/cm² , average fluence 3 J/cm² , every 12h for 6 sessions) in one continuous wave (CW) and two pulsing settings with 20 % and 50 % duty cycles. Cell viability was assessed using MTT, and digital imaging quantified cell migration. After 48 and 72 hours, all treatment groups had significantly higher viability (n = 6, p < 0.05) compared to the control. The highest viability was seen in the pulsed (20% duty cycle) group at the 72-hour time point. PBM improved fibroblast migration in all PBM-treated groups, but differences were not statistically significant (n = 2, p > 0.05). PBM treatments can promote cell viability in both continuous and pulsed modes. Further studies are needed to elucidate the optimal setting for PBM-evoked responses for its rationalized use in promoting specific phases of oral wound healing.

Implementation of Low-Level Laser Therapy in Dentistry: A Review

A type of light therapy known as low-level laser therapy (LLLT) uses only one wavelength of light. Low-level lasers (LLL) do not have a warming effect on the tissues; instead, they have an effect called photobiostimulation. LLL do not evaporate the tissue. The use of LLL to manage a range of illnesses is known as LLLT. Helium-neon lasers are an illustration of an LLLT product. Gallium arsenide, the infrared semiconductor made of gallium aluminum arsenide, is also an example. The performance powers range from 50 to 500 mW with electromagnetic spectrum wavelengths in the red and near-infrared region spanning from 630 to 980 nm and pulsed or continuous-wave emission. In periodontics, LLLT has gained prominence for several applications, including wound healing and pain relief after non-surgical and surgical procedures.

Modulating the Antioxidant Response for Better Oxidative Stress-Inducing Therapies: How to Take Advantage of Two Sides of the Same Medal?

Oxidative stress-inducing therapies are characterized as a specific treatment that involves the production of reactive oxygen and nitrogen species (RONS) by external or internal sources. To protect cells against oxidative stress, cells have evolved a strong antioxidant defense system to either prevent RONS formation or scavenge them. The maintenance of the redox balance ensures signal transduction, development, cell proliferation, regulation of the mechanisms of cell death, among others. Oxidative stress can beneficially be used to treat several diseases such as neurodegenerative disorders, heart disease, cancer, and other diseases by regulating the antioxidant system. Understanding the mechanisms of various endogenous antioxidant systems can increase the therapeutic efficacy of oxidative stress-based therapies, leading to clinical success in medical treatment. This review deals with the recent novel findings of various cellular endogenous antioxidant responses behind oxidative stress, highlighting their implication in various human diseases, such as ulcers, skin pathologies, oncology, and viral infections such as SARS-CoV-2.

Effect of photobiomodulation therapy on patient morbidity and wound healing at donor site after free gingival graft harvesting: a triple-blind randomized-controlled clinical trial

OBJECTIVES

This study aimed to evaluate the effect of photobiomodulation therapy (PBMT) on patient morbidity and donor site healing after free gingival graft (FGG) harvesting.

METHODS

Forty-four patients requiring FGG were selected for this trial. Individuals were randomly assigned to test group (PBMT, n=22) or control group (placebo, n=22) applied immediately after surgery, 24 and 48 hours after. Demographic, surgical-related and psychosocial variables possibly associated with treatment response were collected. The primary outcome was postoperative pain at the donor site evaluated using Visual Analogue Scale (VAS) immediately after surgery and 6, 24, 48 and 72 hours after. Secondary outcomes include medication consumption, patient-reported outcome measures (PROMs) and percentage of wound closure.

RESULTS

Intragroup analysis showed no differences in VASLog means for placebo group throughout the study (p>0.05), whereas a significant difference in PBMT group at 6h, 24h, 48h and 72h (p<0.05) were observed. Postoperative rescue analgesic requirement was significantly higher in the placebo group (p=0.004). The number needed to treat(NNT) was 2.43. PBMT group reported significant better function related to sleeping, going to work/school and daily routine activities, less restriction to mouth opening, chewing and food consumption, less swelling and bleeding (p<0.05), mainly in the first 48hs. PBMT group presented a significantly higher palatal wound closure at 7 days compared to placebo group (33.41 vs 21.20 respectively, p=0.024) after adjustment for confounding. No adverse effects were reported.

CONCLUSIONS

PBMT accelerated the pain resolution time and palatal closure, decreased rescue medication consumption and significantly improved patient satisfaction in the postoperative period.

Emerging treatment strategies in wound care

Wound healing is a complex process in tissue regeneration through which the body responds to the dissipated cells as a result of any kind of severe injury. Diabetic and non-healing wounds are considered an unmet clinical need. Currently, different strategic approaches are widely used in the treatment of acute and chronic wounds which include, but are not limited to, tissue transplantation, cell therapy and wound dressings, and the use of an instrument. A large number of literatures have been published on this topic; however, the most effective clinical treatment remains a challenge. The wound dressing involves the use of a scaffold, usually using biomaterials for the delivery of medication, autologous stem cells, or growth factors from the blood. Antibacterial and anti-inflammatory drugs are also used to stop the infection as well as accelerate wound healing. With an increase in the ageing population leading to diabetes and associated cutaneous wounds, there is a great need to improve the current treatment strategies. This research critically reviews the current advancement in the therapeutic and clinical approaches for wound healing and tissue regeneration. The results of recent clinical trials suggest that the use of modern dressings and skin substitutes is the easiest, most accessible, and most cost-effective way to treat chronic wounds with advances in materials science such as graphene as 3D scaffold and biomolecules hold significant promise. The annual market value for successful wound treatment exceeds over $50 billion US dollars, and this will encourage industries as well as academics to investigate the application of emerging smart materials for modern dressings and skin substitutes for wound therapy.

The Effects of Low-Level Helium-Neon (He-Ne) Laser Irradiation on Lipids and Fatty Acids, and the Activity of Energetic Metabolism Enzymes and Proteome in the Blastula Stage and Underyearlings of the Atlantic Salmon Salmo salar: A Novel Approach in Salmonid Restoration Procedures in the North

The effect of He-Ne laser irradiation on fishery parameters as well as on biochemical state, including the lipids and fatty acids, the activity of energy metabolism enzymes and the proteome in the blastula stage and in underyearlings of wild Atlantic salmon after irradiation at the cleavage stage/early blastula (considered as the stages when the cell has a high potential for differentiation) was studied. Low mortality rates of eggs were determined during embryogenesis, as well as increased weight gain and lower morality rates of underyearlings in the experimental group. This is confirmed by changes in a number of interrelated indicators of lipid metabolism: a decrease in total lipids content, including diacylglycerols, triacylglycerols, cholesterol esters, and the phospholipids content remained unchanged. The embryos in the blastula stage (experimental group) had higher aerobic capacity and an increase in pentose phosphate pathway activity. The proteome profiles of eggs in the blastula stage were 131 proteins, of which 48 were significantly identified. The major protein was found to be phosvitin. The proteomes of underyearlings were represented by 2018 proteins, of which 49 were unique for the control and 39 for the experimental group. He-Ne laser irradiation had a strong effect on the contents of histone proteins.

Effect of photobiomodulation on pain control after clinical crown lengthening surgery

BACKGROUND

Photobiomodulation is a novel technique to reduce pain following different surgeries and treatments. This study aimed to investigate the effect of photobiomodulation on pain control after clinical crown lengthening procedures.

METHODS

Twenty patients were included and randomly assigned to two groups in this single-blind randomized clinical trial. The patients had been referred to the Periodontics Department, Tabriz Faculty of Dentistry, for crown lengthening surgery. In the laser group, diode laser therapy with a wavelength of 860 nm and a power of 100 mW was applied immediately after the surgery on the surgery day and three and seven days after the surgery. In the control group, the laser was turned off, and passive radiation was applied to the area as the test group for 30 seconds per session in non-contact mode. The pain was assessed by a visual analog scale (VAS) questionnaire on the study timelines. Data were analyzed with SPSS 20 using ANOVA and post hoc Tukey tests.

RESULTS

Twenty patients were included in each study group, where the pain was relieved significantly over time. On the first (5.50±1.18) and seventh (1.8±0.42) days, the pain intensity was similar in the test and control groups. However, on the third day, the laser group (2.90±0.74) experienced a significantly lower pain intensity than the control group (4.0±0.67).

CONCLUSION

Photobiomodulation relieved pain after clinical crown lengthening surgeries.

Modified laser-assisted lip repositioning surgery to treat gummy smile

Excessive gingival display (EGD), known as “gummy smile,” is a major esthetic hurdle in today's population. The condition occurs due to various etiologies such as skeletal, dentoalveolar, or soft-tissue origin. The treatment modalities range from orthognathic surgery to periodontal plastic procedures. Lip-repositioning surgery (LRS) is a better alternative for the conventional orthognathic surgery and laser-assisted LRS can be a reliable and a less invasive alternative to conventional (scalpel) LRS. The present case describes the successful treatment of a young female exhibiting an EGD caused by hypermobility of the upper lip and was treated with a modified laser-assisted LRS coupled with gingival recontouring. In a study published earlier, a mild recurrence was observed and hence, to overcome the recurrence, a modified technique, by excising a strip of mucosa with an additional 2 mm of tissue along with the muscular attachment rather than scraping, was attempted.

Photobiomodulation Response From 660 nm is Different and More Durable Than That From 980 nm

BACKGROUND AND OBJECTIVES

Photobiomodulation (PBM) therapy uses light at various wavelengths to stimulate wound healing, grow hair, relieve pain, and more-but there is no consensus about optimal wavelengths or dosimetry. PBM therapy works through putative, wavelength-dependent mechanisms including direct stimulation of mitochondrial respiration, and/or activation of transmembrane signaling channels by changes in water activity. A common wavelength used in the visible red spectrum is ~660 nm, whereas recently ~980 nm is being explored and both have been proposed to work via different mechanisms. We aimed to gain more insight into identifying treatment parameters and the putative mechanisms involved.

STUDY DESIGN/MATERIALS AND METHODS

Fluence-response curves were measured in cultured keratinocytes and fibroblasts exposed to 660 or 980 nm from LED sources. Metabolic activity was assessed using the MTT assay for reductases. ATP production, a major event triggered by PBM therapy, was assessed using a luminescence assay. To measure the role of mitochondria, we used an ELISA to measure COX-1 and SDH-A protein levels. The respective contributions of cytochrome c oxidase and ATP synthase to the PBM effects were gauged using specific inhibitors.

RESULTS

Keratinocytes and fibroblasts responded differently to exposures at 660 nm (red) and 980 nm (NIR). Although 980 nm required much lower fluence for cell stimulation, the resulting increase in ATP levels was short-term, whereas 660 nm stimulation elevated ATP levels for at least 24 hours. COX-1 protein levels were increased following 660 nm treatment but were unaffected by 980 nm. In fibroblasts, SDH-A levels were affected by both wavelengths, whereas in keratinocytes only 660 nm light impacted SDH-A levels. Inhibition of ATP synthase nearly completely abolished the effects of both wavelengths on ATP synthesis. Interestingly, inhibiting cytochrome c oxidase did not prevent the rise in ATP levels in response to PBM treatment.

CONCLUSION

To the best of our knowledge, this is the first demonstration of differing kinetics in response to PBM therapy at red versus NIR wavelength. We also found cell-type-specific differences in PBM therapy response to the two wavelengths studied. These findings confirm that different response pathways are involved after 660 and 980 nm exposures and suggest that 660 nm causes a more durable response. © 2021 Wiley Periodicals LLC.

Effect of photobiomodulation in secondary intention gingival wound healing-a systematic review and meta-analysis

Background

Photobiomodulation is widely being used to improve the wound healing process in dentistry and a vast majority of studies have proven its benefits. But there are plenty of knowledge gaps according to the optimal laser characteristics which should be used to maximize the healing effects of lasers. The goal of this systematic review and meta-analysis was to determine the effect of photobiomodulation (PBM) as an adjunctive treatment to periodontal therapies to evaluate secondary intention gingival wound healing and post-operative pain.

Methods

Five databases (PubMed, Embase, Scopus, ProQuest, and Web of Sciences) were searched up to November 30, 2020, for clinical trials that reported the result of the application of PBM on secondary gingival healing wounds and post-operative pain and discomfort after periodontal surgeries. Two independent reviewers selected the eligible studies and the outcomes of interest were extracted. The quality of eligible studies was assessed using the Cochrane Handbook for Systematic Reviews of Interventions.

Results

Ultimately, twelve studies were included in this review. The application of PBM as an adjunct to periodontal surgeries resulted in a significant improvement in wound healing indices. The Landry wound healing index at the 7th post-operative day was significantly improved (SMD = 1.044 [95% CI 0.62–1.46]; p < 0.01) in PBM + surgery groups compared to the control groups. There was also a statistically significant increase in the complete wound epithelialization (RR = 3.23 [95% CI 1.66–6.31]; p < 0.01) at the 14th post-operative day compared to the control groups. The methods used to assess the post-operative pain were heterogeneous, and therefore the results were limited which made the meta-analysis for post-operative pain assessment not possible.

Conclusion

Based on the results of this review, PBM can be effectively used as a method to improve secondary intention wound healing. High-quality randomized clinical trials, however, are needed in the future to identify the optimal PBM irradiation parameters and the effect of PBM on post-operative pain.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-021-01611-2.

Comprehensive Effects of Photobiomodulation Therapy as an Adjunct to Post-orthodontic Treatment Care: A Systematic Review

PURPOSE

To evaluate the comprehensive effects of photobiomodulation (PBM) therapy on teeth after active orthodontic treatment.

MATERIALS AND METHODS

This systematic review was conducted according to the PRISMA guidelines. Six databases were electronically searched and screened for eligible human and animal studies published up to August 2020. The risk of bias was assessed based on the Cochrane Handbook for Systematic Reviews of Interventions and Systematic Review Centre for Laboratory Experiment Tool. Two independent reviewers performed all procedures in duplicate. Any disagreement was resolved by discussion or consultation with a third reviewer.

RESULTS

A total of 395 records were identified from the initial search up to August 2020. Following screening, 16 full-text articles were reviewed for eligibility (κ > 0.90), and ultimately 9 studies (3 clinical studies and 6 animal studies) were included in this review. The key outcomes observed were 'tooth position maintenance' and 'root resorption rehabilitation'. Two controlled clinical trials and two animal studies supported the preventive effects of PBM therapy on the relapse of post-orthodontic tooth positions, while the other two animal studies reported opposing findings. Regarding root resorption, all evidence supported the rehabilitation potential using PBM therapy for teeth that had undergone orthodontic tooth movement. There was a high risk of bias among studies, except for one randomised controlled trial. Due to the substantial heterogeneity among studies in terms of their types, participants, designs, PBM therapy settings and variables of interest, it was not possible to conduct a meta-analysis; therefore, a qualitative synthesis is presented.

CONCLUSION

The quality of evidence for PBM therapy contributing to the maintenance of tooth position or improved dental health after orthodontic treatment remains low. There is considerable controversy over the effects of PBM therapy on orthodontic relapse. However, the use of PBM therapy after orthodontic treatment has promising effects for root resorption rehabilitation and is generally recommended.

The Effect of Laser Bio-modulation on Dysplastic Lesions, an Animal Study

Potentially malignant disorders are one of the clinical challenges. Dysplasia in these lesions can be a predictor of more potential for malignant changes. Photo-bio-modulation in benign lesions has advantages, but there is doubt on its safety in potentially malignant lesions. This study aims to assess if low-level laser can promote dysplastic changes while the method can play an important role in management of dysplastic lesions. Dysplasia was induced on anterior wall of the buccal pouch of 80 young Syrian male hamsters. Then, hamsters were divided to four groups to receive 4 and 12 sessions irradiation of 660 and 810 nanometers low-level lasers. For histopathologic study of the tissue, we used light microscopes. Using SPSS, data were analyzed via Wilcoxon signed rank test and Mann-Whitney U-test. In all of our four groups, the severity of dysplasia had no statistical difference in study sides comparing with their own controls. Wavelength and numbers of laser irradiation sessions had no statistically meaningful effect on the severity of dysplasia either. Low-level lasers appear to show no relevant or significant effect over the aggravation of the dysplasia's severity. Neither the wavelength nor the number of sessions appear to have any impact in the results.

Effects of different wavelengths of low-level laser therapy on orthodontically induced inflammatory root resorption in rats investigated with micro-computerized tomography

INTRODUCTION

The objective of this research was to investigate the effects of different wavelengths low-level laser therapies on orthodontically induced inflammatory root resorption (OIIRR) during orthodontic tooth movement in rats by micro-computerized tomography.

METHODS

Forty Wistar albino rats were divided into 5 groups: control group (A), 405-nm laser group (B), 532-nm laser group (C), 650-nm laser group (D), and 940-nm laser group (E). The left side of group A was used as a positive control (A-PC), and the right side of group A was used as a negative control (A-NC) group. In all groups, the maxillary left first molars were moved mesially by 50 g of force for 14 days. The lasers were performed for 9 minutes on the maxillary left first molar tooth. At the end of the experimental period, OIIRR measurements were performed at the mesial and the distal sides along the mesial root of the maxillary first molars.

RESULTS

The root resorption volume was significantly lower in group A-NC than in groups A-PC, B, and D. The percentage of root resorption was significantly lower in group A-NC than in all other groups. The root resorption volume and the percentage of root resorption in groups C, D, and E were significantly lower than group A-PC. The depth and the width of the lacuna and even the number of mesial lacunae were similar between groups. The distal and the total lacunae were significantly lower in group A-NC than in all other groups except group C.

CONCLUSIONS

The 532-nm, 650-nm, and 940-nm lasers significantly reduced the volume of OIIRR. In addition, the 532-nm laser reduced the number of lacunae both distally and totally than all the other groups.

The effect of low-level laser therapy as an adjunct to periodontal surgery in the management of postoperative pain and wound healing: a systematic review and meta-analysis

The meta-analysis and systematic review aimed to evaluate the effect of low-level laser therapy (LLLT) as an adjunct to periodontal surgery in the management of postoperative pain and wound healing. An electronic search in 4 databases (PubMed, Embase, Cochrane, and OpenGrey) was conducted for randomized clinical trials reporting the effectiveness of LLLT used as an adjunct to periodontal surgery to alleviate pain and accelerate wound healing compared with surgery alone. Finally, 13 studies were eligible and included. The results showed a significant difference of pain relief between groups at day 3 post-surgery, whereas no difference was found at day 7. Moreover, a significant reduction was observed in the mean analgesic intake during the first week in the LLLT group. On day 14, the adjunctive use of LLLT showed significantly faster re-epithelialization and better wound healing in palatal donor sites following free gingival graft procedures. Based on the results, LLLT used as an adjunct to periodontal surgery positively influenced postsurgical pain control. Low power (≤ 500 mW) combined with energy density ≥ 5 J/cm² might be more appropriate for postoperative pain relief. Moreover, adjunctive LLLT to free gingival grafts could significantly accelerate wound healing of palate sites at early healing phase. Multicenter studies using different LLL parameters without postsurgical analgesics are needed to determine optimal laser settings.

Evaluation of the effects of photobiomodulation therapy and ozone applications after gingivectomy and gingivoplasty on postoperative pain and patients' oral health-related quality of life

The aim of this study was to evaluate the effects of photobiomodulation therapy (PBM) and ozone applications on patients' quality of life after gingivectomy and gingivoplasty. In this study, 36 patients with chronic inflammatory gingival enlargement underwent gingivectomy and gingivoplasty. The groups were randomly divided into control (n = 12), PBM (n = 12) and ozone (n = 12) groups. GaAlAs diode laser 810 nm wavelength at a non-contact and continuous mode with a power of 0.3 W and a density of 4 J/cm² used for PBM for 1 min. Ozone was applied for 1 min for every 5 mm² in contact mode at power level 9 using probe number 3. PBM and ozone applications were performed immediately after the operation, on the 3rd and 7th days. Pain assessment was performed at 3rd, 7th, 14th and 28th days after gingivectomy and gingivoplasty by using visual analogue scale (VAS). Oral Health Impact Profile (OHIP-14) records were obtained from the patients before gingivectomy and gingivoplasty and postoperative 7th and 14th days. OHIP-14 questions were also evaluated individually. VAS pain levels of the control group measured on the 3rd day were higher than the PBM group and on the 7th day were found to be significantly higher than both groups (p < 0.05). The total OHIP-14 score of the control group on the 7th postoperative day was found to be higher than the PBM group (p < 0.05). The mean score obtained from the third question of OHIP-14 at 7th and 14th day of the PBM group was found to be lower than the control and ozone groups (p < 0.05). The PBM and ozone applications after gingivectomy and gingivoplasty reduce the pain levels of patients and have a positive effect on patients' quality of life.

Cellulose nanocrystals/nanofibrils loaded astaxanthin nanoemulsion for the induction of apoptosis via ROS-dependent mitochondrial dysfunction in cancer cells under photobiomodulation

The present study investigated effects of low-level laser therapy with cellulose nanocrystals/cellulose nanofibrils loaded in nanoemulsion (NE) against skin cancer cells on apoptosis. The nanoemulsion was fabricated and characterized by the standard methods. The toxicity level by cytotoxicity assays, generation of reactive singlet oxygen (ROS) and antioxidant potential, cell proliferation and migration were confirmed by using standard assays. The cellular uptake efficacy was evaluated by differential staining. The protein levels of EGFR, PI3K, AKT, ERK, GAPDH, and β-actin were detected by western blot. The samples showed a spherical shaped structure with the average size confirmed strong and stable hydrogen bonding forces with high degradation temperature and endothermic transition peaks. The fabricated samples showed no toxicity and high cell proliferation by generating more singlet oxygen levels and antioxidants. The intracellular signaling pathways was regulated with high protein expression levels, which was stimulated by specific molecules for cell proliferation, migration, and differentiation in cancer cells. The results proved that combined treatment regulated the intracellular signaling pathways in cancer cells. The current study showed a novel strategy for improving therapeutic efficacy of nanoemulsion by using low-level laser therapy. Further, the current favorable outcomes will be evaluated in in vivo animal models.

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.