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

Examining the combined benefits of photobiomodulation and apigenin for the treatment of asthenozoospermia: An innovative therapeutic strategy

Individuals suffering from asthenospermia, an infertility disorder, have reduced sperm motility. This study's goal was to identify the impacts of diverse photobiomodulation procedures on the motility of sperm in vitro in patients with asthenospermia, either in isolation or in combination with Apigenin. At 633 nm and 808 nm, the lasers are used with multiple dose values (0.6, 1.2, and 2.4) J/cm2 and altering Apigenin concentrations (5, 10, 25, and 50 μM). All of the photobiomodulation procedures were assessed. Assessing factors were the DNA fragmentation index, sperm viability, as well as progressive sperm motility. The progressive sperm motility results for 633 nm and 808 nm show a significant increase over 633 nm + 808 nm after 60 min after irradiation. Sperm motility increased more quickly under the 808 nm procedure than under the other procedures (p < 0.02). The observation of progressive sperm motility indicated that a 10 μM concentration of Apigenin created higher results than other concentrations (p < 0.01). Apigenin with 808 nm at 1.2 J/cm2 resulted in better sperm motility (p < 0.01) and decreased DNA fragmentation index. There was a notable increase (p < 0.05) in the DNA fragmentation index with the 633 nm + 808 nm procedure. At a 10 μM concentration of Apigenin, the DNA fragmentation index was lower than at a 50 μM concentration (p < 0.02). Neither Apigenin nor photobiomodulation significantly decreased sperm viability. The study suggests that asthenozoospermia patients may benefit from apigenin utilized alongside photobiomodulation, while further investigation is required.

Simultaneous irradiation of 660 and 808 nm on gingival epithelial cells and fibroblasts induces different patterns of oxidative/antioxidative activities: What is the role of the cell type and irradiation parameters?

The aim of this study was to investigate whether simultaneous irradiation at 660 and 808 nm generates different patterns of oxidative/antioxidative activities compared to consecutive irradiation. Primary cultures of gingival keratinocytes and fibroblasts were exposed to a diose laser (660 ± 2 nm and 808 ± 2 nm, 100 mW, 0.09 cm2 spot area) using double irradiation with the two wavelengths (consecutive or simultaneous) for 6, 10, and 20 s. The two irradiation regimens did not increase cell viability in any of the experimental conditions. Lipid peroxidation was increased after consecutive irradiation in epithelial cells, which was not detected after simultaneous irradiation. After 20s of the simultaneous mode, ROS levels increased, but antioxidative balance decreased. In the fibroblasts, the two double irradiations induced ROS reduction, increase in lipid peroxidation, and improvement of antioxidative balance, mainly after the 20 s irradiation time. In conclusion, simultaneous and consecutive irradiation induced distinct oxidative stress modulation in oral epithelial cells and fibroblasts. The imbalance in the oxidative system observed after longer exposures, allied with the absence of a significant increase in the viability of the two cell types, suggests a contraindication for longer simultaneous irradiation in clinical situations that demand cellular stimulation.

The use of laser photobiomodulation as pre-anesthetic tissue management technique in reducing injection pain in children

BACKGROUND

One of the main goals for pediatric dentists is to offer a painless anesthesia experience. Laser photobiomodulation is among the suggested strategies to decrease injection pain. So, this study aimed to assess the impact of laser photobiomodulation on local anesthesia (LA) injection pain in children and its effect on the efficacy of LA during pulpotomy and SSC procedures.

METHODS

The research was carried out as a randomized controlled clinical trial with two parallel group design. It involved 64 cooperative healthy children, age range from 5 to 7 years, each having at least one maxillary molar indicated for pulpotomy. Children were randomly allocated to one of the two groups based on the pre-anesthetic tissue management technique used: test group received laser photobiomodulation, while control group received topical anesthetic gel. Pain during injection, pulpotomy, and SSC procedures was assessed using physiological measures (Heart Rate (HR)), subjective evaluation (modified Face-Pain-Scale (FPS), and objective analysis (Sound-Eye-Motor scale (SEM)).

RESULTS

A total of 64 children with mean age 6.23 ± 0.78 participated in this research. The mean HR scores were significantly lower in the laser PBM group during buccal and palatal infiltration injections. The SEM mean scores were significantly lower in the laser PBM group during both injections. For the FPS scale, the number of children who recorded satisfaction during injection was significantly higher in laser PBM group. There was no statistically significant difference in mean HR as well as in SEM and FPS scores between the two groups during pulpotomy and SSC procedures. Comparisons between the two study groups were performed using independent samples t- and Mann-Whitney U tests. Significance was set at p value < 0.05.

CONCLUSION

Laser photobiomodulation is a promising non-pharmacological pre-anesthetic tissue management technique in children that offered less painful injection compared to topical anesthetic gel without compromising the effectiveness of LA.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05861154. Registered on 16/5/2023.

Enhanced Recovery of Local Anesthesia in Pediatric Patients: The Impact of Photobiomodulation on Reversing Anesthesia Effects

BACKGROUND The split-mouth study design is used in oral health research and usually consists of 2 treatments randomly assigned to either the right or left side. This split-mouth study aimed to evaluate the efficacy of photobiomodulation on reversal of local anesthesia in 50 children aged 8-10 years. MATERIAL AND METHODS The study was conducted among 50 children: 27 girls and 23 boys, aged 8-10 years (mean age 9.38±1.15 years), who presented 2 carious maxillary permanent molars. One side was randomly assigned to the laser group (50 teeth), and the contralateral side to the control group (50 teeth). At the end of the treatment, photobiomodulation (PBM) was performed in the area of infiltration at 6 points, with 635 nm (25 children) (250 mW, 500 mW/cm², 15J) and 808 nm (25 children) (200 mW, 400 mW/cm², 12J) (SmartM PRO, Lasotronix, Poland). On the contralateral side, the laser's off-mode applicator was used. Anesthetic effect was evaluated by palpation test (soft tissues) and electrical test (dental pulp). RESULTS After 15 minutes, in the laser group the return to normal sensations in the palpation test showed 88% (808 nm) and 68% (635 nm), and only 20% in the control group (P=0.04123). After 45 minutes, all the participants from the PBM group returned to normal sensations (P=0.21458). Dental pulp's excitability threshold was lower for both wavelengths compared to the control group (P=0.000001). CONCLUSIONS The identification of factors accelerating the recovery time to normal function, such as PBM, can be used as important data to eliminate self-injury secondary to local anesthesia (LA) in children.

A radiographic and histological study to compare red (650 nm) versus near infrared (810 nm) diode lasers photobiomodulation for alveolar socket preservation

Previous findings indicated that the laser photobiomodulation is more effective than the control or placebo in preserving the alveolar socket. This study aimed to compare two different lasers regarding their effectiveness in aiding alveolar socket preservation. Twenty extraction sockets were selected then divided into two equal groups. Group A was exposed to 650 nm Diode laser, and Group B to 810 nm Diode laser following the same protocol and parameters after a standard alveolar socket preservation procedure with collagen plug. Radiographic analysis with cone beam computed tomography was done to compare the alveolar bone surface area immediately after extraction and three months post-operatively, while bone samples collected before implant drilling were histologically examined for newly formed bone evaluation and histomorphometric analysis in terms of percentage of new bone surface area, percentage of unmineralized bone and finally, immunohistochemical analysis of Osteocalcin reaction surface area as well as optical density. Radiographically, infrared (810 nm) Diode effect on alveolar bone surface area has significantly exceeded the red laser, while histologically, red (650 nm) Diode has demonstrated statistical significance regarding all parameters; newly formed bone surface area percentage, unmineralized bone area percentage and finally Osteocalcin bone marker reaction surface area percentage and optical density. Under the specified conditions and laser parameters, photobiomodulation using the 810 nm Diode got the upper hand radiographically, yet histologically, the red 650 nm Diode managed to dominate all histological parameters when both employed as an adjunct to alveolar socket preservation procedures.

Laser Applications in Regenerative Endodontics: A Review

Introduction: Developing regenerative endodontic treatment (RET) is an exciting approach to managing immature permanent teeth with pulp necrosis. RET is usually performed in two clinical steps: disinfection (first step) and tissue engineering (second step). Recently, laser therapy has entered the field of RET. This study aimed to provide an overview of the literature that employed laser therapy for root regeneration. Methods: A comprehensive search was performed on four databases, including PubMed, Web of Science, Scopus, and Google Scholar. The searched keywords were laser, regenerative endodontics, immature permanent teeth, and dental pulp necrosis, and related English-published articles were included up to October 2023. Results: Thirteen studies utilized a laser for RET. In the first step of RET, both high-power and low-level lasers (through photodynamic therapy [PDT]) may be applied for canal disinfection. In contrast, regenerative procedures in the second step of RET are just accelerated by low-power lasers (biostimulation). The literature does not support the benefit of laser-assisted irrigation in improving the clinical success of RET. There is some evidence that laser-assisted disinfection with a diode laser may provide comparable results to triple antibiotic paste in reducing bacterial counts in root canals while providing slightly better clinical and radiographic outcomes. PDT may be an effective and suitable adjunct to conventional disinfection methods in immature, necrotic teeth. Conclusion: Low-power lasers may be beneficial tools for improving the results of regenerative endodontics through chemical disinfection in the first step (PDT) or by biostimulation in the second step of RET.

Photobiomodulation Effects on Periodontal Ligament Stem Cells: A Systematic Review of In Vitro Studies

BACKGROUND

Stem cell therapy has been considered to play a paramount role in the treatment modalities available for regenerative dentistry. The established beneficial effects of photobiomodulation (PBM) at the cellular level have led to the combined use of these two factors (PBM and stem cells). The main goal of this study was firstly to critically appraise the effects of PBM on periodontal ligament stem cells (PDLSCs), and secondly to explore the most effective PBM protocols applied.

METHODS

Pubmed, Cochrane, Scopus, Science Direct, and Google Scholar search engines were used to identify experimental in vitro studies in which PBM was applied to cultured PDLSCs. After applying specific keywords, additional filters, and inclusion/exclusion criteria, a preliminary number of 245 articles were narrowed down to 11 in which lasers and LEDs were used within the 630 - 1064 nm wavelength range. Selected articles were further assessed by three independent reviewers for strict compliance with PRISMA guidelines, and a modified Cochrane risk of bias to determine eligibility.

STATISTICAL ANALYSIS

The dataset analysed was extracted from the studies with sufficient and clearly presented PBM protocols. Simple univariate regression analysis was performed to explore the significance of contributions of potential quantitative predictor variables toward study outcomes, and a one-way ANOVA model was employed for testing differences between the laser or LED sources of the treatments. The significance level for testing was set at α = 0.05.

RESULTS

The proliferation rate, osteogenic differentiation, and expression of different indicative genes for osteogenesis and inflammation suppression were found to be positively affected by the application of various types of lasers and LEDs. With regard to the PBM protocol, only the wavelength variable appeared to affect the treatment outcome; indeed, the 940 nm wavelength parameter was found not to exert a favourable effect.

CONCLUSIONS

Photobiomodulation can enhance the stemness and differentiation capacities of periodontal ligament stem cells. Therefore, for PBM protocols, there remains no consensus amongst the scientific community. Statistical analyses performed here indicated that the employment of a near-infrared (NIR) wavelength of 940 nm may not yield a significant favourable outcome, although those within the 630 - 830 nm range did so. Concerning the fluence, it should not exceed 8 J/cm2 when therapy is applied by LED devices, and 4 J/cm2 when applied by lasers, respectively.

Investigation of the optimal light parameters for photobiomodulation to induce osteogenic differentiation of the human bone marrow stem cell and human umbilical vein endothelial cell co-culture

Bones have an important role in the human body with their complex nature. Mesenchymal stem cells and endothelial cells together support their unique and complex nature. Photobiomodulation (PBM) is a promising method that provides cell proliferation, osteogenic differentiation, and bone regeneration. However, there are still unknowns in the mechanism of osteogenic differentiation induced by PBM. The main aim of the study is to understand the molecular mechanism of PBM at 655 and 808 nm of wavelengths and identify the most effective energy densities of both wavelengths for osteogenic differentiation. The effect of PBM on osteogenic differentiation of Human Bone Marrow Stem Cell (hBMSC) and Human Umbilical Vein Endothelial Cell (HUVEC) co-culture was examined at 1, 3, and 5 J/cm2 energy densities of red and near-infrared light through different analysis such as cell viability, scratch assay, intracellular reactive oxygen species production, and ATP synthesis, nitric oxide release, temperature monitoring, and osteogenic differentiation analyses. Even though all PBM-treated groups exhibited better results compared to the control group, 5 J/cm2 energy density induced faster cell proliferation and migration at both wavelengths. The increases in ATP and NO levels as signaling molecules, and the increases in DNA, ALPase, and calcium contents as osteogenic markers were higher in the groups treated with 5 J/cm2 energy density at both wavelengths. Only a slight change was obtained in the level of intracellular ROS after any light applications. It can be concluded that NO release has a very important role together with ATP production in PBM therapy to trigger DNA synthesis, ALPase activity, and mineralization for osteogenic differentiation of the hBMSC and HUVEC co-culture at 655 and 808 nm of wavelengths.

Photobiomodulation therapy assisted orthodontic tooth movement: potential implications, challenges, and new perspectives

Over the past decade, dramatic progress has been made in dental research areas involving laser therapy. The photobiomodulatory effect of laser light regulates the behavior of periodontal tissues and promotes damaged tissues to heal faster. Additionally, photobiomodulation therapy (PBMT), a non-invasive treatment, when applied in orthodontics, contributes to alleviating pain and reducing inflammation induced by orthodontic forces, along with improving tissue healing processes. Moreover, PBMT is attracting more attention as a possible approach to prevent the incidence of orthodontically induced inflammatory root resorption (OIIRR) during orthodontic treatment (OT) due to its capacity to modulate inflammatory, apoptotic, and anti-antioxidant responses. However, a systematic review revealed that PBMT has only a moderate grade of evidence-based effectiveness during orthodontic tooth movement (OTM) in relation to OIIRR, casting doubt on its beneficial effects. In PBMT-assisted orthodontics, delivering sufficient energy to the tooth root to achieve optimal stimulation is challenging due to the exponential attenuation of light penetration in periodontal tissues. The penetration of light to the root surface is another crucial unknown factor. Both the penetration depth and distribution of light in periodontal tissues are unknown. Thus, advanced approaches specific to orthodontic application of PBMT need to be established to overcome these limitations. This review explores possibilities for improving the application and effectiveness of PBMT during OTM. The aim was to investigate the current evidence related to the underlying mechanisms of action of PBMT on various periodontal tissues and cells, with a special focus on immunomodulatory effects during OTM.

Interaction of the AKT and β-catenin signalling pathways and the influence of photobiomodulation on cellular signalling proteins in diabetic wound healing

The induction of a cells destiny is a tightly controlled process that is regulated through communication between the matrix and cell signalling proteins. Cell signalling activates distinctive subsections of target genes, and different signalling pathways may be used repeatedly in different settings. A range of different signalling pathways are activated during the wound healing process, and dysregulated cellular signalling may lead to reduced cell function and the development of chronic wounds. Diabetic wounds are chronic and are characterised by the inability of skin cells to act in response to reparative inducements. Serine/threonine kinase, protein kinase B or AKT (PKB/AKT), is a central connection in cell signalling induced by growth factors, cytokines and other cellular inducements, and is one of the critical pathways that regulate cellular proliferation, survival, and quiescence. AKT interacts with a variety of other pathway proteins including glycogen synthase kinase 3 beta (GSK3β) and β-catenin. Novel methodologies based on comprehensive knowledge of activated signalling pathways and their interaction during normal or chronic wound healing can facilitate quicker and efficient diabetic wound healing. In this review, we focus on interaction of the AKT and β-catenin signalling pathways and the influence of photobiomodulation on cellular signalling proteins in diabetic wound healing.

Effect of 810 nm Diode Laser Irradiation on the Time of Initiation and Depth of Anesthesia for Endodontic Treatment of Mandibular First Molars with Symptomatic Irreversible Pulpitis: A Clinical Trial

Objective: In endodontic treatments, performing appropriate anesthesia in patients with irreversible pulpitis in mandibular molars may result in pain and severe problems. The irradiation of low-level lasers could be effective in this regard due to its anti-inflammatory and regenerative properties. This study aimed to assess the effect of 810 nm diode laser on the time of initiation and depth of anesthesia for endodontic treatment of mandibular first molars with symptomatic irreversible pulpitis. Materials and methods: This randomized controlled clinical trial evaluated 60 patients requiring endodontic treatment of mandibular first molars with symptomatic irreversible pulpitis and pain score ≥114 according to the Heft-Parker visual analog scale (HP-VAS). The teeth were randomized into two groups of diode laser and control. In the diode laser group, 810 nm diode laser with 300 mW power and 15 J/cm2 energy density was irradiated to the buccal surface of tooth crowns for 20 sec at 2 mm distance immediately before anesthesia administration. Laser in off mode was used in the control group. Inferior alveolar nerve block was then performed using 2% lidocaine with 1:80,000 epinephrine. After anesthetic injection, the mandibular first molar and canine teeth (control) were tested by an electric pulp tester every 2 min. Two consecutive negative responses to 80 mA indicated the initiation of anesthesia. HP-VAS forms were filled out by patients to assess their level of pain during the procedure. Data were analyzed by the Student's t and Chi-square tests, and analysis of variance (α = 0.05). Results: No remarkable difference was noted between the laser group and control groups in pain severity or anesthesia onset (p > 0.05). Conclusions: Low-level (810 nm) diode laser did not affect the time of initiation or depth of anesthesia in endodontic treatment of mandibular first molars with symptomatic irreversible pulpitis. Clinical trials registration: Iranian Registry of Clinical Trials (IRCT20181222042076N1).

Effect of Photobiomodulation on the Depth of Local Anesthesia during Endodontic Treatment of Teeth with Symptomatic Irreversible Pulpitis

AIM

To determine whether photobiomodulation (PBM) therapy could increase the depth of analgesia during endodontic therapy of teeth affected with symptomatic irreversible pulpitis.

MATERIALS AND METHODS

Forty-nine patients with symptomatic irreversible pulpitis were randomized into two groups. In the laser group, before administering anesthesia, the lower molars' crowns were continuously treated with a diode laser (980 nm) for 20 s with a low-level laser tip in the buccal aspect close to the gingival margin. While the teeth of the second group who was blinded to the type of treatment received placebo treatment wherein the laser device was switched off. The visual analogue scale (VAS) was used to assess pain in both groups before the endodontic procedure, during dentin cutting, and at dropping pulp, wherein, the success was defined as no or mild pain. The Chi-square and independent sample t-tests were used to assess the data.

RESULTS

During dentin cutting and pulp dropping, the group receiving the laser therapy presented with less mean pain score than the placebo group which was statistically significant. Additionally, it was observed that the need for supplementary injection was less frequent in the laser-treated group than in the placebo group (p = 0.01).

CONCLUSION

The irradiation by diode laser (980 nm) prior to administration of local anesthesia appears to be useful in minimizing discomfort and additional injection during root canal therapy (RCT).

CLINICAL SIGNIFICANCE

Pain management is essential for providing the best possible treatment to patients before, during, and after endodontic therapy. Adequate pain control during treatment also aids in reducing postoperative discomfort. This implies the need for additional methods to reduce discomfort during endodontic treatment; hence, adjuncts are crucial to achieving this goal. Photobiomodulation may be used as an adjuvant to reduce discomfort and supplementary injections during RCT.

Evaluation of the effectiveness of photobiomodulation therapy as an alternative method to local anesthesia injection in pediatric dentistry

Background

The idea of receiving local anesthesia (LA) via an injection is a major source of dental fear and anxiety. In children, dental anxiety is considered the main reason for avoiding dental treatments. Moreover, there are potential complications during/after LA administration. Thus, it is necessary to search for painless, low-risk, and nonpharmacological anesthetic approaches.

Aim

This study was performed to evaluate the effectiveness of photobiomodulation (PBM) therapy as an alternative method to LA injection for conventional restorative treatments in pediatric patients.

Settings and Design

This was a split-mouth randomized clinical study.

Materials and Methods

The study included 15 children between 6 and 12 years old. Each child had 2 similar contralateral caries lesions in the first permanent molars in the same jaw, total (30) teeth. For each child, one tooth was treated under conventional LA injection and the other was treated under PBM-based anesthesia. The Wong-Baker's Faces Pain Scale was used for reporting the pain and discomfort levels at the end of the treatments.

Statistical Analysis

Data statistical analysis was performed using the Statistical Package for the Social Sciences (SPSS) version 20. Mann-Whitney U-test was used to compare between the groups.

Results

The PBM-based anesthesia group recorded a mean pain score of 2.27 ± 1.28. The conventional LA group recorded a mean pain score of 1.73 ± 0.7. The difference between the groups was not statistically significant (P = 0.168).

Conclusions

PBM-based anesthesia may be an optional alternative to LA injection for conventional restorative treatments in children with dental anxiety, needle phobia, or special needs, and it deserves further studies and improvement.

Photothermal Effects of High-Energy Photobiomodulation Therapies: An In Vitro Investigation

The purpose of this study was to investigate photothermal aspects of photobiomodulation therapies (PBMT) in vitro to assist in the development of safe clinical parameters with respect to higher-power devices with large surface applicators. Laser wavelengths in the range of 650 nm-1064 nm were investigated using a thermal camera. Thermographic measures of surface and sub-surface temperature variations of similar lean porcine muscle tissue samples were recorded for a series of calibrated experiments. A thermal comparison was then made between Flat-top and Gaussian beam spatial distribution devices. Outcome data were subjected to statistical analysis using an ANOVA model. Results acquired at similar parameters of irradiance indicated that the application of the 980 nm wavelength was associated with the highest rise in temperature, which decreased with other wavelengths in the order 980 > 1064 ≈ 650 >>> 810 nm (p < 5 × 10^-20). All wavelengths assessed were associated with a significant temperature increase, and with the exception of 810 nm, all exceeded the threshold of a 6 °C rise within the prescribed parameter limits. Optical scanning by movement of the applied source over a relevant area was found to offer effective mitigation of these temperature increases. An extended discussion is presented, analysing the clinical significance of the study outcomes. Recommendations are made within the limits of this in vitro study in order to assist future clinical investigations.

Influence of Three Laser Wavelengths with Different Power Densities on the Mitochondrial Activity of Human Gingival Fibroblasts in Cell Culture

Phototherapy plays a key role in wound healing and tissue regeneration. The use of lasers has the potential to become an effective and minimally invasive treatment in periodontal and peri-implant disease. The aim of this study was to evaluate the influence of three laser wavelengths with the combination of parameters such as power density and energy density on human gingival fibroblasts (hGFs) in vitro culture. Isolated cells were seeded in 96-well plates with culture medium (DMEM, Dulbecco's modified Eagle's medium) supplemented with 10% fetal bovine serum (FBS). After 24 h cells were irradiated (1064, 980 and 635 nm, various energy density value). After 24, 48 and 72 h, cells were evaluated for viability. Data were analyzed by ANOVA followed by Tukey's HSD test. We found the best outcomes for hGFs irradiated with laser 1064 nm for all combinations of power output (50/400/1000 mW) and energy dose (3/25/64 J/cm²) after 48 h and 72 h compared with control group. Cell viability increase ranged from 0.6× (3 J/cm², 50 mW) to 1.3× (64 J/cm², 1000 mW). Our findings indicate that the appropriate use of low-level laser irradiation (LLLI) can increase the proliferation rate of cultured cells. The use of LLLI can be extremely useful in tissue engineering and regenerative medicine.

Photobiomodulation for the management of xerostomia and oral mucositis in patients with cancer: a randomized clinical trial

To evaluate the applicability of photobiomodulation therapy (PBM-T) in the management of xerostomia and OM. Fifty-three patients with head and neck squamous cell carcinoma were randomized into two groups: Sham and PBM-T. The Sham group received artificial saliva and laser simulation, while the PBM-T group received artificial saliva and PBM-T. Xerostomia-related quality of life (QoL), the presence or absence of OM lesions, the decayed-missing-filled teeth (DMFT) index, and periodontal charts were evaluated. The results of the QoL questionnaire, DMFT index, and periodontal chart were analyzed with the Kruskal-Wallis test, followed by the Student-Newman-Keuls test, while OM findings were compared using the Mann-Whitney test. QoL scores significantly increased in the Sham group (p < 0.0001), denoting more severe xerostomia symptoms (p = 0.0074), and decreased in the PBM-T group, indicating no or very mild xerostomia. Higher grades of OM were found in the Sham group than the PBM-T group (p = 0.0001). There was no significant difference in DMFT index or periodontal charts between the groups (p > 0.05). PBM-T improved QoL in patients with head and neck cancer treated with radiotherapy, whether as radiation alone or as an adjunct to chemotherapy and surgery.

Does luminosity and smear layer influence 810 nm laser energy transmission through human dentine?

PURPOSE

The aim of this study was to evaluate the influence of luminosity values and smear layer on transmission characteristics of 810 nm near infrared laser energy through dentine, using extracted human teeth.

METHODS

A total of 200 teeth treated with endodontic medicaments to cause discolouration (Ledermix, Doxypaste or Odontopaste) were selected, to give a range of values for tooth shade (luminosity values). Sectioned teeth had smear layer created or removed. Near-infrared laser energy transmission was assessed using an 810 nm diode laser (90 mW, CW mode) with the tip placed at 2 mm and 4 mm from the external root surface, and a laser power metre.

RESULTS

Both tooth shade and smear layer had independent attenuating effects. Transmission of laser energy was significantly lower in teeth with darker shades. There was a strong positive correlation between relative luminosity (lighter tooth colour) and transmitted laser power (r = 0.9271 for the Spearman rank correlation, P = 0.0022). When a smear layer was present, this significantly reduced the transmission of laser energy through the sample, compared to when no smear layer was present.

CONCLUSION

The results of this laboratory study highlight the attenuating influence of a darker tooth shade and the presence of smear layer on the transmission of 810 nm light when directed onto the surface of human dentine. Such effects may be relevant to photo biomodulation, Photodynamic Therapy and other dental laser treatments.

Single session of laser photobiomodulation for symptom management of oral lichen planus: a retrospective study

This study aimed to evaluate the effectiveness of a single session of laser photobiomodulation (PBM) with flat top handpiece in reducing painful symptoms in patients with Oral Lichen Planus (OLP). The clinical charts of 20 patients of the Dental Clinic of University of Padua (Italy) who underwent a single laser PBM to manage OLP symptomatology were retrospectively analyzed. A 980 nm diode laser and a flat top handpiece with a 1-cm2 spot area were employed to perform the PBM with a single session protocol. VAS pain scores were assessed before and after the laser PBM, the day after, and on the 7th and 30th days after the treatment. No adverse effects occurred within 30 days after treatment. The mean VAS-pain score was 3.8 (SD 2.3) before PBM; 2.6 (SD 2.0) after PBM; 1.9 (SD 2.2) on day 1; 2.0 (SD 2.3) on day 7; and 1.5 (SD 2.2) on day 30. VAS pain decreased significantly over time (p < 0.0001). A single session of laser PBM may be safe and effective in reducing pain for symptomatic OLP patients. Further investigations are required to include placebo or topical corticosteroids as comparators.

Different Treatment Modalities of Oral Lichen Planus-A Narrative Review

Oral lichen planus (OLP) is a chronic inflammatory disease of unknown etiology which affects the oral mucosa. OLP varies in its clinical features from a reticular form that is, in most cases, asymptomatic, to atrophic-erosive, and is accompanied by symptoms of burning sensation and pain followed by difficulty in eating. Given the fact that OLP is a disease of unknown etiology, the treatment is symptomatic and involves suppressing the signs and symptoms of the disease using various topical and systemic drugs. The first line of therapy for treating symptomatic OLP is topical corticosteroids, whereas systemic corticosteroids are used for treating persistent lesions that do not respond to local treatment. However, the lack of convincing evidence on the efficacy of previous therapies, including topical corticosteroids, and numerous side effects that have appeared over recent years has resulted in the emergence and development of new therapeutic options. Some of the therapies mentioned are tacrolimus, efalizumab, dapson, interferon, retinoic acid, photochemotherapy with psoralen and ultraviolet A rays (PUVA), aloe vera, antimalarials, antibiotics and others. These therapies only partially meet the properties of efficacy and safety of use, thus justifying the continuous search and testing of new treatment methods.

Evaluation of the effects of photobiomodulation with different laser application doses on injection pain in children: a randomized clinical trial

The utilization of photobiomodulation (PBM) to decrease the experience of pain during the application of local anesthesia (LA) has been reported in a limited number of studies with children. However, currently, there is no complete consensus regarding its efficacy and application doses. The objective of the clinical trial was to assess the effects of PBM with three different laser application doses (with different power values) plus 10% lidocaine topical anesthetic and to compare them with placebo + 10% lidocaine topical anesthetic on LA injection pain in children. A prospective, parallel-arm, randomized, triple-blind clinical trial was conducted with 160 children aged 6 to 12 years (79 girls and 81 boys; 80 maxillary and 80 mandibular primary first molars). The children were divided into 4 groups with an equal number of subjects in each group. Before topical anesthetic usage, a laser with a power of 0.3 W, 0.4 W, and 0.5 W was applied in Groups 1, 2, and 3, respectively (a diode laser: 940 nm; continuous mode; 20 s for each group). The energy density was calculated as 69 J/cm2, 92 J/cm2, and 115 J/cm2. A placebo laser was used in the fourth group. Injection pain was assessed subjectively and objectively with the Wong-Baker Faces Pain Rating Scale (PRS) and the Face, Legs, Activity, Cry, Consolability (FLACC) Scale. The data were analyzed using the Chi-square test (P < 0.05). The mean (± std) PRS scores were 1.35 ± 1.075, 1.37 ± 1.05, 1.07 ± 1.04, and 2.07 ± 1.09 for Groups 1, 2, and 3 and the placebo group, respectively. Additionally, the mean (± std) FLACC scores were 1.67 ± 1.50, 1.62 ± 1.90, 1.35 ± 1.74, and 2.75 ± 1.64 for Groups 1, 2, and 3 and the placebo group, respectively. Groups 1, 2, and 3 showed significantly lower pain scores than the placebo group (P = 0.02). However, no significant difference was observed between Groups 1, 2, and 3 according to either pain scale score (P = 0.948). In addition, no relationship was found in pain scores related to sex and jaw differences in any group (P = 0.321, P = 0.248). PBM delivered by a 940-nm diode laser plus 10% lidocaine topical anesthetic before the application of LA decreased injection pain regardless of the applied laser dose in this study.

Effect of Photobiomodulation on Atrophic-Erosive Clinical Forms of Oral Lichen Planus: A Systematic Review

INTRODUCTION

Oral lichen planus is a chronic autoimmune inflammatory disease of unknown origin, characterized by various clinical forms of which the atrophic-erosive causes patients the greatest symptomatology. For this reason, there are different treatments that improve the associated signs and symptoms. One of these therapies is photobiomodulation (PBM), which, although new, has a high level of acceptance in dentistry based on evidence. However, there are inconsistent results in its application against lichen planus. The aim of this review was to evaluate the effect of photobiomodulation and its effectiveness as a therapeutic alternative for atrophic-erosive lesions.

MATERIAL AND METHODS

The databases PubMed, Google Scholar and Cochrane Library were searched to identify studies investigating the photobiomodulation treatment in atrophic-erosive lesions of oral lichen planus. A total of 294 articles were identified, published between 2017 and 2022, and then evaluated; 7 articles that met all the inclusion criteria were included in this study.

RESULTS

The type of laser light source used in PBM was the diode laser (four cases), the Nd-YAG laser at the same wavelength of 1064 nm (two cases) and the He-Ne laser (one case). The minimum and maximum wavelengths used were 630 nm and 1064 nm, respectively. Most studies used lesions treated with topical corticosteroids as a control group. The follow-up times of the studies were highly variable.

CONCLUSIONS

Photobiomodulation is a treatment that competently combats oral lichen planus lesions by improving signs and symptoms, with no known adverse reactions so far, which makes it more beneficial compared to more conventional therapies, such as corticosteroids, for which side effects have been found.

Laser Er:YAG-Assisted Debonding May Be a Viable Alternative to the Conventional Method for Monocrystalline Ceramic Brackets

In orthodontic practice, due to the increased interest among patients in smile aesthetics, different types of brackets are now being used, with those most frequently applied being ones made of polycrystalline and monocrystalline ceramic. The aim of this study was to evaluate the laser Er:YAG-assisted debonding technique compared to conventional methods for removing monocrystalline ceramic brackets from human teeth. The study sample included 60 vital teeth (frontals of the upper jaw) from 10 patients who had monocrystalline ceramic brackets and were in the final phase of orthodontic treatment. The debonding procedure was carried out following a split-mouth study design, using either the conventional technique or laser Er:YAG 2940 nm radiation. For each tooth, three variables were evaluated: the patient's sujective tooth sensitivity associated with the debonding, the time required for debonding, and pulp blood flow microdynamics after the debonding. Three evaluation instruments were used to assess and quantify the treatment effects: (i) the Wong-Baker FACES Pain Rating Scale for pain assessment; (ii) a digital stopwatch/timer to measure the time required to remove the bracket; and (iii) laser Doppler flowmetry (LDF) for recording the pulp blood flow evolution. The statistical analysis of the recorded data showed a statistically significant difference between the two debonding methods regarding the tooth sensitivity during the debonding and the time required for the procedure. The subjective tooth sensitivity was reduced from a mean ± standard deviation of 3.07 ± 1.46 to 0.47 ± 0.86 on the Wong-Baker FACES scale (Wilcoxon signed rank, p < 0.001). The necessary time for debonding was reduced by 0.697 ± 0.703 s per tooth (paired t-test, p < 0.001). There was no difference in the blood microdynamics between the two debonding techniques. According to the results of this study, the laser Er:YAG-assisted debonding technique may be a viable alternative to the conventional method for monocrystalline ceramic brackets.

Two-year Follow-up of Avulsed Teeth Submittted to Laser Therapies: A Case Report

Background:

Replanted teeth can lead to critical biological conditions involving ankylosis and external root resorption. To prevent these occurrences, antimicrobial Photodynamic Therapy (aPDT) and Photobiomodulation Therapy (PBMT) can be used during the postoperative phase.

Case Report:

The present report described the clinical case of a patient, an adult male with the avulsion of teeth #11 and #21. Teeth were stored under dry conditions and replanted 18h after trauma. The pulp was removed before replantation and aPDT was performed using a low power laser (660 nm,100 mW, 9 J) in direct irradiation of the root canal. A passive flexible splint was fixed in place from tooth #13 to #23 for 4 weeks. The PBMT was applied three times a week, for the first 2 months, using the same laser device but with an infrared wavelength (808 nm, 100 mW, 3J). Clinical and radiographic examination supported the assessment of inflammatory/infectious resorption.

Conclusion:

The combination of laser therapy with endodontic procedures for treating traumatized teeth ensured successful clinical and radiographic outcomes at a 2-year follow-up examination.

Three-Dimensional Assessment of the Temporomandibular Joint Changes Following Reversed Twin Block Therapy of Patients With Skeletal Class III Malocclusion in Conjunction With the Photobiomodulation Therapy: A Randomized Controlled Clinical Trial

BACKGROUND

Despite the positive effect of the photobiomodulation therapy (PBMT) application on animals, the primary role of this technique on the human condyle is still unclear. Several experimental reports have shown the efficacy of PBMT in inducing cellular changes in the temporomandibular joint (TMJ) region during functional treatment of patients with skeletal deformities. Still, the lack of information about its effects on human condyles requires further studies.

OBJECTIVES

This study aimed to evaluate the effect of PBMT on the TMJ components following Class III treatment with the reversed twin block (RTB) appliance in growing patients.  Materials and Method: Forty children (12 females, 28 males) between the age of nine and eleven years with skeletal Class III were assigned randomly to the RTB group with photobiomodulation (RTB+PBMT) or the control group (RTB). The PBMT was applied to the TMJ region using an 808-nm wavelength Ga-Al-As semiconductor laser device with 5 Joules/cm2 energydensity on days 1, 3, 7, and 14 of the first month. Afterwards, the irradiation was conducted every 15 days until the end of the treatment. Cone-beam computerized tomography (CBCT) images were taken before (T1) treatment and following the end of treatment (T2) to assess TMJ and skeletal changes.

RESULTS

Condylar volume was significantly increased in the RTB group only by a mean of 287.97 mm3 (p<0.001). The significantly backward and upward condylar movement was observed in the RTB and RTB+PBMT groups (superior joint space (SJS): 0.26 mm, 0.15 mm; posterior joint space (PJS): 0.42mm, 0.11mm, respectively). The RTB group showed the most remarkable changes. Significant improvement of the sagittal maxilla-mandibular relationship was greater in the RTB+PBMT group compared to the RTB group (p=0.02).

CONCLUSION

There were no considerable differences in the condylar position after Class III treatment between the RTB and the RTB+PBMT groups. But a difference in the condylar volume was noticed between the two group.

Effect of low-level laser therapy on condylar growth in children treated with functional appliance: a preliminary study

Purpose

This study aimed to evaluate the skeletal and dentoalveolar changes achieved by combining low-level laser irradiation applied on the condyle area with twin-block therapy in growing class II malocclusion patients.

Methods

Fourteen patients (9 males, 5 females; mean age, 11.4 ± 2 years) with skeletal class II mandibular deficiency were recruited. They were divided into two groups (G 1: twin-block + low-level laser therapy, G 2: twin-block only). A semiconductor diode laser with a wavelength of 940 nm was applied on the condyle area (100 mW, 2.5 J, 3.9 J/cm²). The laser was applied twice a week in the first month and once a week in the second and third months, totalizing 16 sessions. Skeletal, dental, and soft-tissue cephalometric parameters were measured and compared at different treatment points.

Results

Mandibular length (Co-Gn) was significantly increased by 3.6 mm in the experiment group (3.16 SD) and 4.3 mm (4.4 SD) in the control group, with no significant difference between groups at every time point (P-value 0.949 at T2). Similarly, a statistically significant positive effect of treatment was found in both groups on ramus height (Co-Go), upper lip to E-Line, SNA angle, ANB angle, and U1/SN angle with no significant difference between groups.

Conclusion

Based on the results of this preliminary study, low-level laser irradiation with the used parameters seems to have no synergetic impact on the skeletal and dental outcomes of twin-block therapy over 9 months. However, more studies are needed to investigate the effect of low-level laser therapy on condylar growth during functional orthodontic treatment.

Supplementary Information

The online version contains supplementary material available at 10.1007/s41547-022-00158-x.

Efficacy of concentrated growth factor with low-level laser for the regeneration of interdental papilla defects

Gingival "black triangle" is common in clinical which due to interdental papilla recession. The cause of the loss of papilla is multi-factorial and it may be caused by the absorption of interdental alveolar bone or abnormal tooth position. Besides, it is a common complication after orthodontics and implant surgery. Recession of gingival papilla influences interdental plaque control, increasing food impaction and alveolar bone absorption, causing aesthetic and pronunciation problems. Thus, the way of reducing or eliminating the gingival "black triangle" has become one of the most essential problems for dentists. Concentrated growth factor (CGF) and low-level-laser therapy have been widely used, respectively, and CGF was considered as the only self-substance which has soft tissue regeneration function. This study aims to evaluate the efficacy of regenerating interdental papilla by Liquid phase concentrated growth factor (LPCGF) injection with low-level-laser therapy (LLLT).

Efficacy of compound topical anesthesia combined with photobiomodulation therapy in pain control for placement of orthodontic miniscrew: a double-blind, randomized clinical trial

This study aims to investigate the effect of compound topical anesthetic (CTA) application combined with photobiomodulation therapy (PBMT) on the level of pain perceived during placement of miniscrews and 24 h post the procedure in the buccal side of the maxillary bone. This randomized, prospective, single-center, split-mouth, double-blinded study included 25 subjects (12 males and 13 females, aged 16 to 35). Two anesthetic techniques before implantation were performed including Profound gel +PBM with 980 nm diode laser and local anesthesia with 2% lidocaine hydrochloride. Then, the miniscrews with the size of 1.6 mm in diameter and 8 mm in length were placed with a hand driver in the buccal side of the maxillary bone. The pain immediately after miniscrew placement (T1), also 12 h (T2), and 24 h (T3) post the procedure were collected by visual analog scale (VAS). Data were analyzed by SPSS version 22. There were no statistically significant differences in mean VAS scores within or between CTA combined with PBMT or injection applications, immediately after miniscrew placement (P = 0.75), 12 h after miniscrew placement (P = 0.4), and 24 h after miniscrew placement (P = 1.0). Compound topical anesthetic combined with PBMT provided adequate local anesthesia for the placement of miniscrews in the buccal side of the maxillary bone.

The influence of delivery power losses and full operating parametry on the effectiveness of diode visible-near infra-red (445-1064 nm) laser therapy in dentistry-a multi-centre investigation

The development of protocols for laser-assisted therapy demands strict compliance with comprehensive operating parametry. The purpose of this investigation was to examine the accuracy of correlation between laser control panel and fibre emission power values in a selection of diode dental lasers. Through retrospective analysis using successive systematic review and meta-analysis, it is clear that there is inconsistency in the details, and possible inaccuracies in laser power applied and associated computed data. Through a multi-centre investigation, 38 semi-conductor ("diode") dental laser units were chosen, with emission wavelengths ranging from 445 to 1064 nm. Each unit had been recently serviced according to manufacturer's recommendations, and delivery fibre assembly checked for patency and correct alignment with the parent laser unit. Subject to the output capacity of each laser, four average power values were chosen using the laser control panel-100 mW, 500 mW, 1.0 W, and 2.0 W. Using a calibrated power meter, the post-fibre emission power value was measured, and a percentage power loss calculated. For each emission, a series of six measurements were made and analysed to investigate sources of power losses along the delivery fibre, and to evaluate the precision of power loss determinations. Statistical analysis of a dataset comprising % deviations from power setting levels was performed using a factorial ANOVA model, and this demonstrated very highly significant differences between devices tested and emission power levels applied (p < 10-142 and < 10-52 respectively). The devices × emission power interaction effect was also markedly significant (p < 10-66), and this confirmed that differences observed in these deviations for each prior power setting parameter were dependent on the device employed for delivery. Power losses were found to be negatively related to power settings applied. Significant differences have emerged to recommend the need to standardize a minimum set of parameters that should form the basis of comparative research into laser-tissue interactions, both in vitro and in vivo.

Photobiomodulation of gingival lesions resulting from autoimmune diseases: systematic review and meta-analysis

Objectives

To evaluate the effects of photobiomodulation (PBM) in gingival lesions resulting from autoimmune diseases; to compare PBM and topical corticosteroid (CS) treatment; and to assess PBM outcome over time of follow-up.

Materials and methods

A comprehensive electronic search was performed in four electronic databases. Treatment effects were measured through visual analog scale of pain (VAS) and clinical evolution of lesion (Thongprasom scale for oral lichen planus (OLP)). Meta-analysis was performed to compare PBM with topical corticosteroid treatment and to evaluate PBM effect over time of follow-up.

Results

Seventeen studies were included in this review, of which six were used for the meta-analysis. Meta-analysis results showed no significant differences between PBM and topical CS in pain reduction at baseline (MD = 0.20, 95% CI =  − 0.92, 1.32, p = 0.72) and 60-day follow-up (MD = 0.63, 95% CI =  − 3.93, 5.19, p = 0.79); however, VAS showed significant pain reduction when compared before and after PBM at 30-day (MD =  − 3.52, 95% CI =  − 5.40, − 1.64, p = 0.0002) and 60-day (MD =  − 5.04, 95% CI =  − 5.86, − 4.22, p < 0.00001) follow-up. Thongprasom clinical scale for OLP also showed significant improvement at 30-day follow-up (MD =  − 2.50, 95% CI =  − 2.92, − 2.08, p < 0.00001) after PBM.

Conclusion

PBM led to significant reduction of pain and clinical scores of the lesions, not having shown significant differences when compared to topical CS.

Clinical relevance

PBM has been used in the treatment of autoimmune gingival lesions, but so far there is little strong evidence to support its use.

Bioenergetics of photobiomodulated osteoblast mitochondrial cells derived from human pulp stem cells: systematic review

Dental pulp cells are a source of multipotent mesenchymal stem cells with a high proliferation rate and multilineage differentiation potential. This study investigated the photobiomodulated bioenergetic effects of mitochondria in osteoblasts that differentiated from human pulp stem cells. The systematic review followed PRISMA guidelines. The PICO question was formulated. Criteria for inclusion and exclusion were established prior to searches being performed on the PubMed/MEDLINE, Embase, and Scopus. Articles were identified and included if published in English within last 10 years; photobiomodulation or low-level laser therapy were discussed; the delivery parameters for dose and time were included and the studies focused on bioenergetics of osteoblast mitochondria. Studies excluded were non-human dental pulp tissue and in vivo studies. A total number of 110 articles were collated, 106 were excluded leaving a total of 4 articles. These studies demonstrated that in vitro use of photobiomodulation was performed using different laser and LED types; InGaAlP; InGaN; and InGaAsP with average wavelengths of 630 to 940 nm. Primary human osteoblastic STRO-1 and mesenchymal stem cell lineages were studied. Three out of four articles confirmed positive bioenergetic effects of photobiomodulation on mitochondria of osteoblasts derived from human pulp cells. This systematic review demonstrated a lack of adequate reporting of bioenergetics of osteoblast mitochondria after photobiomodulation treatment.