Low-level laser therapy affects dentinogenesis and angiogenesis of in vitro 3D cultures of dentin-pulp complex

In vitro bioactive dentin protein release by diode laser conditioning

This in-vitro study aimed to explore the potential of Diode Laser by quantifying the release of transforming growth factor-beta 1 (TGF-β1), platelet-derived growth factor (PDGF)-BB, and vascular endothelial growth factor (VEGF) from root dentin after ethylenediaminetetraacetic acid (EDTA) and diode laser. In 30 hemi-roots distributed into five groups: G1: Tris-buffered solution (TBS); G2: 17%EDTA; G3: 17% EDTA +650 nm Diode Laser; G4:17% EDTA +810 nm Diode Laser; and G5: 810 nm Diode Laser. The concentration of the three factors was quantified using a cytokine bead array. Statistical tests were performed to estimate intergroup differences (p ≤ 0.05). TGF-β1 and VEGF were solubilised in all test protocols. The ability of low-level power diode lasers to release proteins from the matrix is limited. Its effect on the release of VEGF and PDGF-BB does not make a difference. A synergy between EDTA and Diode Laser led to a greater proportion of TGF-β1 release.

Assessment of photobiomodulation by a 660-nm diode laser on the reversal of soft tissue anesthesia in children: A randomized controlled clinical trial

BACKGROUND

Soft tissue anesthesia (STA) following inferior alveolar nerve block (IANB) anesthesia lasts 3-5 h. It is important to reverse STA after treatment to prevent soft tissue injury (STI).

AIM

This study evaluated photobiomodulation using a 660 nm diode laser on STA reversal and its impact on STI following IANB anesthesia.

DESIGN

A randomized controlled clinical trial was conducted on 32 children, aged 5-8 years, allocated into the test and control groups. Anesthesia was administered; the operative procedure was performed followed by exposure to laser. STA reversal was monitored through lip tapping, current perception threshold (CPT) tests, and paediatric Functional Assessment Battery.

RESULTS

The test group showed significantly faster recovery to normal sensation following exposure to laser than the control group which did not undergo any reversal (p < .0001), with a median time of 115 and 60 min according to lip tapping and CPT tests, respectively. The test group also showed significantly faster recovery to normal function (p = .016). The incidence of STI in the form of redness was significantly higher in the control group (p = .022).

CONCLUSION

Photobiomodulation using a 660 nm diode laser can be considered as an efficient approach to minimize STA and STI after dental interventions.

Photo biomodulation of dental derived stem cells to ameliorate regenerative capacity: In vitro study

Background

Dental regeneration benefits from improving the features of dental derived stem cells. Gallium-aluminum-arsenide laser had a significant role in modification of cell behavior in different cell lines and culture conditions. Hence, exploring its mechanism and effect on dental derived stem cells would benefit prospective regenerative dental therapies.

Objectives

To assess the impact of photo biomodulation by Low-Level-Laser on isolated Dental Pulp derived Stem Cells and Periodontal Ligament derived Stem Cells regarding their proliferation and osteogenic differentiation.

Methods

Isolated DPSCs and PDLSCs from impacted third molars were subjected to Gallium-aluminum-arsenide laser for 12 sec and 3.6 J/cm2. The proliferative capacity was evaluated via 3-(4,5-dimethylthiazol-2-yl),2,5-diphenyltetrazolium bromide (MTT) Assay and Trypan blue stain. Cell osteogenic differentiation potentials were assessed by alkaline phosphatase assay and alizarin red stain, polymerase chain reaction was performed to quantify Nuclear factor Kappa gene expression.

Results

DPSCs subjected to laser bio-stimulation showed the best results regarding cell viability (MTT) and osteogenic differentiation (ALP assay), and calcium deposition at 3 intervals (3, 7, 14 days), meanwhile, PDLSCs subjected to laser bio-stimulation showed better result than control but less than DPSCs. While NF-KB gene expression was proven to be approximately comparable for both groups. Generally, the Photo-bio modulated groups showed better results than their control groups.

Conclusion

Low-level laser bio-stimulation (LLL) therapy improves DPSC and PDLSC osteogenic differentiation and proliferation via the activation of the NF-KB pathway. Also, the DPSCs outperformed PDLSCs in terms of performance.

Clinical significance

These results can be beneficial information and a reference database for more research in tissue engineering, dental therapy, and regeneration.

The application of lasers in vital pulp therapy: a review of histological effects

Vital pulp therapy (VPT) is primarily intended to preserve the vitality of pulp tissues, which have been exposed for any reason. Various materials and techniques have been proposed to improve treatment outcomes, including the use of lasers. This study aimed to review the histological results of different dental lasers including low-level lasers, carbon dioxide (CO2), erbium-doped yttrium aluminum garnet laser (Er:YAG), neodymium-doped yttrium aluminum garnet (Nd:YAG), erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) lasers, and diode lasers for VPT. This focused review included a comprehensive electronic search of Scopus, MEDLINE, Web of Science, and Google Scholar databases from 2000 to 2022 by two independent investigators. Different combinations of keywords were used, and reference mining of related papers was done. The review included studies related to histologic evaluation of laser-assisted vital pulp therapy that stated the laser parameters that were used. Articles with radiographic or clinical assessments or articles lacking necessary data were excluded. Non-English articles were excluded unless their abstract was in English and encompassed the necessary data. Most studies indicated the efficacy of lasers for reduction of inflammation, acceleration of healing, and increasing the thickness of dentinal bridge. According to the evidence, lasers used in combination with pulp capping agents are beneficial to enhance the success rate of VPT.

Biomodulator of Diode Laser Irradiation on Odontoblast-Like Cells by Expression of Vascular Endothelial Growth Factor-A and Transforming Growth Factor-β1

OBJECTIVE

 This study aimed to prove that the effect of diode laser 650-nm irradiation to the expression of vascular endothelial growth factor (VEGF)-A and transforming growth factor (TGF)-β1 plays important roles in dental pulp-regulating cell proliferation, differentiation, and revascularization.

MATERIALS AND METHODS

 The research was performed by randomized posttest only control group design using Rattus norvegicus. A total of 48 samples were provided and divided into eight groups of 6 samples each with a random-sample allocation. Each group were prepared, and perforation of maxillary first molar were done. In control groups (groups 1-4), glass ionomer cement (GIC) was used to restore the teeth, while in laser groups (groups 5-8), the teeth were irradiated with diode laser 650 nm for 40 seconds before application of GIC. Half of the groups (groups 1, 2, 5, and 6) were necropsied in 7 days, and the rest (groups 3, 4, 7, and 8) were necropsied in 14 days. Immunohistochemistry (IHC) evaluation were implemented to check the expression of both VEGF-A and TGF-β1.

STATISTICAL ANALYSIS

 Both data of VEGF-A and TGF-β1 expression were analyzed using a one-way ANOVA (α = 0.05) with SPSS statistical software.

RESULTS

 The study showed that the diode laser 650-nm irradiation increased expression of VEGF-A and TGF-β1, and there was a significant difference between diode laser and control group on VEGF-A expression (p = 0.001) and TGF- β1 (p = 0.000) on days 7 and 14.

CONCLUSION

 Diode laser 650 nm with 40-second irradiation time shows increment from day 7 to day 14 reflecting increase in pulp healing by modulating VEGF-A and TGF-β1 expression since days 7 to 14.

Effect of copper oxide nanoparticles and light-emitting diode irradiation on the cell viability and osteogenic/odontogenic differentiation of human stem cells from the apical papilla

OBJECTIVES

This experimental study aimed to assess the effect of copper oxide nanoparticles (CuONPs) and light-emitting diode (LED) irradiation on the cell viability and osteogenic/odontogenic differentiation of human SCAPs.

METHODS

After the culture of SCAPs, the effects of different concentrations of CuONPs on cell viability were evaluated by the methyl thiazolyl tetrazolium (MTT) assay after 24 and 48 h, and the optimal concentration was determined (n = 12). SCAPs were then divided into four groups based on the type of treatment: (I) no-treatment control group, (II) exposure to CuONPs, (III) LED irradiation (635 nm, 200 mW/cm²) for 30 s, and (IV) exposure to CuONPs combined with LED irradiation. CuONPs were synthesized by a green technique, which was based on reduction and simultaneous stability of copper ions by using the pomegranate peel extract. After treatments, the expression of osteogenic/odontogenic markers including dentin sialophosphoprotein (DSPP), bone sialoprotein (BSP), alkaline phosphatase (ALP), and dentin matrix acidic phosphoprotein 1 (DMP1) was evaluated in all four groups using quantitative real-time polymerase chain reaction (PCR) (n = 16). Also, osteogenic differentiation of SCAPs was evaluated qualitatively by alizarin red staining (ARS) to assess the matrix mineralization (n = 4). SPSS version 18 was used for data evaluation. The Kruskal-Wallis and Mann-Whitney tests were used to compare the groups.

RESULTS

Exposure to 1 µg/mL CuONPs resulted in maximum viability of SCAPs. Concentrations of CuONPs over 10 µg/mL significantly decreased the viability of SCAPs. Real-time PCR showed that the expression of DMP1, BSP, ALP, and DSPP in CuONPs + LED and LED groups was significantly higher than that in CuONPs and control groups at both 24 and 48 h (P < 0.05). The density of ARS increased in all experimental groups after 24 h, and in CuONPs + LED and CuONPs groups after 48 h, compared to the control group.

CONCLUSION

Addition of CuONPs and LED irradiation of SCAPs in the culture medium significantly enhanced their osteogenic/odontogenic differentiation.

Activation of Wnt/β-Catenin Signaling Involves 660 nm Laser Radiation on Epithelium and Modulates Lipid Metabolism

Research has proven that light treatment, specifically red light radiation, can provide more clinical benefits to human health. Our investigation was firstly conducted to characterize the tissue morphology of mouse breast post 660 nm laser radiation with low power and long-term exposure. RNA sequencing results revealed that light exposure with a higher intervention dosage could cause a number of differentially expressed genes compared with a low intervention dosage. Gene ontology analysis, protein-protein interaction network analysis, and gene set enrichment analysis results suggested that 660 nm light exposure can activate more transcription-related pathways in HC11 breast epithelial cells, and these pathways may involve modulating critical gene expression. To consider the critical role of the Wnt/T-catenin pathway in light-induced modulation, we hypothesized that this pathway might play a major role in response to 660 nm light exposure. To validate our hypothesis, we conducted qRT-PCR, immunofluorescence staining, and Western blot assays, and relative results corroborated that laser radiation could promote expression levels of β-catenin and relative phosphorylation. Significant changes in metabolites and pathway analysis revealed that 660 nm laser could affect nucleotide metabolism by regulating purine metabolism. These findings suggest that the Wnt/β-catenin pathway may be the major sensor for 660 nm laser radiation, and it may be helpful to rescue drawbacks or side effects of 660 nm light exposure through relative interventional agents.

Photobiomodulation in 3D tissue engineering

SIGNIFICANCE

The method of photobiomodulation (PBM) has been used in medicine for a long time to promote anti-inflammation and pain-resolving processes in different organs and tissues. PBM triggers numerous cellular pathways including stimulation of the mitochondrial respiratory chain, alteration of the cytoskeleton, cell death prevention, increasing proliferative activity, and directing cell differentiation. The most effective wavelengths for PBM are found within the optical window (750 to 1100 nm), in which light can permeate tissues and other water-containing structures to depths of up to a few cm. PBM already finds its applications in the developing fields of tissue engineering and regenerative medicine. However, the diversity of three-dimensional (3D) systems, irradiation sources, and protocols intricate the PBM applications.

AIM

We aim to discuss the PBM and 3D tissue engineered constructs to define the fields of interest for PBM applications in tissue engineering.

APPROACH

First, we provide a brief overview of PBM and the timeline of its development. Then, we discuss the optical properties of 3D cultivation systems and important points of light dosimetry. Finally, we analyze the cellular pathways induced by PBM and outcomes observed in various 3D tissue-engineered constructs: hydrogels, scaffolds, spheroids, cell sheets, bioprinted structures, and organoids.

RESULTS

Our summarized results demonstrate the great potential of PBM in the stimulation of the cell survival and viability in 3D conditions. The strategies to achieve different cell physiology states with particular PBM parameters are outlined.

CONCLUSIONS

PBM has already proved itself as a convenient and effective tool to prevent drastic cellular events in the stress conditions. Because of the poor viability of cells in scaffolds and the convenience of PBM devices, 3D tissue engineering is a perspective field for PBM applications.

Efficacy of Mineral Trioxide Aggregate and Photobiomodulation on Pulp Capping of Dogs’ Teeth

AIM: The present study assessed the effect of mineral trioxide aggregate (MTA) and photobiomodulation (PBM) on pulp capping of exposed pulp of dogs’ teeth. METHODS: Forty-eight teeth in three mongrel dogs were randomly divided into two major study groups; Group I where MTA was used as a pulp capping agent and Group II in which both MTA+PBM were used. The groups were equally subdivided according to the observation period following completion of pulp capping into Subgroup (A) 1 week, Subgroup (B) 2, and Subgroup (C) 16 weeks. The teeth were examined for histological inflammatory response as well as dentine bridge formation. RESULTS: With regard to inflammatory response at 1 week significantly, less intense inflammation was observed in MTA+PBM (Group II) compared to the MTA (Group I) for the same time period with no significant difference for between Group I and Group II for other time intervals. As for dentin bridge formation, PBM+MTA groups showed statistically significant thicker dentine bridge formation at 16 weeks than MTA alone group for the same time period with no significant difference for between Group I and Group II for other time intervals. CONCLUSIONS: Under the conditions of this study, PBM appeared to be a beneficial adjunct in dental pulp capping procedures in which MTA was the pulp capping material.

Low-power therapeutic lasers on mRNA levels

Gene expression evaluation in cells and biological tissues has been crucial for research in biology, medicine, biotechnology, and diagnostic. Messenger ribonucleic acid (mRNA) levels show relationship with gene expression, and they can be measured by real-time quantitative polymerase chain reaction (RT-qPCR) for the quantification of steady-state mRNA levels in cells and biological tissues. Radiations emitted from low-power lasers induce photobiomodulation, which is the base of therapeutic protocols for disease treatment. Despite that the understanding on photobiomodulation has been improved by mRNA level evaluation, laser irradiation parameters and procedures are diversified among studies, harming the comparison of RT-qPCR data. In this systematic review, data from mRNA levels reported in photobiomodulation studies were summarized regarding the process, function, and gene. Literature search was conducted for the assessment of published reports on mRNA levels evaluated by RT-qPCR in cells and biological tissues exposed to low-power lasers. Data showed that mRNA levels have been evaluated by RT-qPCR for a variety of genes related to molecular, cellular, and systemic processes after low-power violet-orange, red, and infrared laser exposure. Results from gene expression have increased the understanding of the mechanisms involved in photobiomodulation, and they can be useful to increase the efficacy and safety of clinical applications based on low-power lasers.

Pulpal and periapical tissue response after direct pulp capping with endosequence root repair material and low-level laser application

Background

The study aims to investigate the pulp and periapical reaction and healing after capping with EndoSequence Root Repair Material (ERRM) combined with low-level laser application.

Methods

In 6 rabbits, pulps were exposed via class V, half of the samples received a low-level diode laser at 980 nm. Thereafter, cavities were capped with regular-set ERRM. The specimens were processed for histomorphological examination after 2 weeks and two months.

Results

After 2 weeks, images show mild inflammation and organized odontoblasts in lased group. The non-lased group shows more severe inflammation. The predentin thickness was thicker in the lased group with statistical significance (p < 0.05). After 2 months, inflammatory cells were sparse in both lased and non-lased groups. In the periapical area, group one showed dilated blood vessels and thick fibrous connective tissues. In group two, there were more numerous maturations of PDL fibers with scattered inflammatory cells and congested blood vessel.

Conclusions

Using low-level laser therapy in combination with ERRM for pulp capping shortens the inflammatory phase and enhances healing.

The effect of low-level laser on the quality of dentin barrier after capping with bioceramic material: A histomorphometric analysis

The study aims to investigate the quality of dentin barriers and pulp reaction to EndoSequence Root Repair Material (ERRM) combined with low-level laser application. In eight dogs, pulps were exposed via class V, half of the samples received low-level diode laser at 870 nm. Thereafter, cavities were capped with fast-set or regular-set ERRM. The specimens were processed for histomorphological and immunohistochemical examination after 2 weeks and 2 months. Dentin bridges were observed in all samples, and 87.5% were complete. The low-level laser group had significantly more reparative dentin area than the non-lased group (p < 0.05). The dentin bridges were found to have an unprecedented tubularity of 43%-89%. Tiny dentin island formation was observed within the material particles. Initial mild-to-moderate inflammatory reactions were observed, which subsided after 2 months. RUNX2 and osteocalcin staining were evident for all samples at both time intervals. Low-level laser combined with bioactive ERRM is effective in inducing reparative dentin formation.

Efficacy of Photobiomodulation and Vitamin D on Odontogenic Activity of Human Dental Pulp Stem Cells

Introduction: The regeneration of dental pulp tissue using human dental pulp stem cells (HDPSCs) has attracted increasing attention in recent years. Recent studies have suggested that several factors such as photobiomodulation (PBM) and vitamin D affect the proliferation and differentiation of HDPSCs. Therefore, the present study evaluated the effects of PBM and vitamin D on odontogenic differentiation of HDPSCs for dentin -like tissue formation. Methods: HDPSCs were collected, isolated, and characterized and then divided into six groups: group I, control; group II, vitamin D (10^-7 Mol); group III, irradiation at 1 J/cm² of 810 nm diode laser; group IV, irradiation at 1 J/cm² and culture with vitamin D; group V, irradiation at 2 J/cm², and group VI, irradiation at 2 J/cm² and culture with vitamin D, cell viability assay was measured through MTT. Alkaline phosphatase (ALP) enzyme activity and mRNA levels of vascular endothelial growth factor (VEGF), bone morphogenic protein-2 (BMP-2), and dentin sialophosphoprotein (DSPP) were also assessed. Results: PBM at 1 and 2 J/cm² combined with vitamin D significantly promoted HDPSCs proliferation through MTT assay and odontogenic differentiation through gene expression of VEGF, BMP-2, and DSPP levels (P < 0.0001). Conclusion: PBM at 2 J/cm² combined with vitamin D enhanced the HDPSCs proliferation and odontogenic differentiation and thus could be a novel strategy for dentin regeneration in dentistry.

Wnt Signalling in Regenerative Dentistry

Teeth are complex structures where a soft dental pulp tissue is enriched with nerves, vasculature and connective tissue and encased by the cushioning effect of dentin and the protection of a hard enamel in the crown and cementum in the root. Injuries such as trauma or caries can jeopardise these layers of protection and result in pulp exposure, inflammation and infection. Provision of most suitable materials for tooth repair upon injury has been the motivation of dentistry for many decades. Wnt signalling, an evolutionarily conserved pathway, plays key roles during pre- and post-natal development of many organs including the tooth. Mutations in the components of this pathway gives rise to various types of developmental tooth anomalies. Wnt signalling is also fundamental in the response of odontoblasts to injury and repair processes. The complexity of tooth structure has resulted in diverse studies looking at specific compartments or cell types of this organ. This review looks at the current advances in the field of tooth development and regeneration. The objective of the present review is to provide an updated vision on dental biomaterials research, focusing on their biological properties and interactions to act as evidence for their potential use in vital pulp treatment procedures. We discuss the outstanding questions and future directions to make this knowledge more translatable to the clinics.

Sinking Our Teeth in Getting Dental Stem Cells to Clinics for Bone Regeneration

Dental stem cells have been isolated from the medical waste of various dental tissues. They have been characterized by numerous markers, which are evaluated herein and differentiated into multiple cell types. They can also be used to generate cell lines and iPSCs for long-term in vitro research. Methods for utilizing these stem cells including cellular systems such as organoids or cell sheets, cell-free systems such as exosomes, and scaffold-based approaches with and without drug release concepts are reported in this review and presented with new pictures for clarification. These in vitro applications can be deployed in disease modeling and subsequent pharmaceutical research and also pave the way for tissue regeneration. The main focus herein is on the potential of dental stem cells for hard tissue regeneration, especially bone, by evaluating their potential for osteogenesis and angiogenesis, and the regulation of these two processes by growth factors and environmental stimulators. Current in vitro and in vivo publications show numerous benefits of using dental stem cells for research purposes and hard tissue regeneration. However, only a few clinical trials currently exist. The goal of this review is to pinpoint this imbalance and encourage scientists to pick up this research and proceed one step further to translation.

Photobiomodulation combined with adipose-derived stem cells encapsulated in methacrylated gelatin hydrogels enhances in vivo bone regeneration

Reconstruction of bone defects is still a significant challenge. The aim of this study was to evaluate the effect of application of photobiomodulation (PBM) to enhance in vivo bone regeneration and osteogenic differentiation potential of adipose-derived stem cells (ADSCs) encapsulated in methacrylated gelatin (GEL-MA) hydrogels. Thirty-six Sprague-Dawley rats were randomly separated into 3 experimental groups (n = 12 each). The groups were control/blank defect (I), GEL-MA hydrogel (II), and ADSC-loaded GEL-MA (GEL-MA+ADSC) hydrogel (III). Biparietal critical sized bone defects (6 mm in size) are created in each animal. Half of the animals from each group (n = 6 each) were randomly selected for PBM application using polychromatic light in the near infrared region, 600-1200 nm. PBM was administered from 10 cm distance cranially in 48 h interval. The calvaria were harvested at the 20th week, and macroscopic, microtomographic, and histologic evaluation were performed for further analysis. Microtomographic evaluation demonstrated the highest result for mineralized matrix formation (MMF) in group III. PBM receiving samples of group III showed mean MMF of 79.93±3.41%, whereas the non-PBM receiving samples revealed mean MMF of 60.62±6.34 % (p=0.002). In terms of histologic evaluation of bone defect repair, the higher scores were obtained in the groups II and III when compared to the control group (2.0 for both PBM receiving and non-receiving specimens; p<0.001). ADSC-loaded microwave-induced GEL-MA hydrogels and periodic application of photobiomodulation with polychromatic light appear to have beneficial effect on bone regeneration and can stimulate ADSCs for osteogenic differentiation.

Could the photobiomodulation therapy induce angiogenic growth factors expression from dental pulp cells?

This study aimed to evaluate the effect of different photobiomodulation (PBM) radiant exposures on the viability, proliferation, and gene expression of pulp fibroblasts from human primary teeth (HPF) involved in the pulp tissue repair. HPF were irradiated with Laser InGaAlP (Twin Flex Evolution, MMOptics®) at 660-nm wavelength (red); single time, continuous mode, 0.04-cm² laser tip area, and 0.225-cm laser tip diameter, keeping the distance of 1 mm between the laser beam and the cell culture. The doses used were between 1.2 and 6.2 J/cm² and were evaluated at the 6 h, 12 h, and 24 h after PBM. MTT and crystal violet assays evaluated the cell viability and proliferation. RT-PCR verified VEGF and FGF-2 mRNA expression. A blinded examiner analyzed the data through two-way ANOVA followed by Tukey test (p < 0.05). The groups with higher powers (10 mW, 15 mW, 20 mW, and 25 mW), shortest application periods (10 s), and radiant exposures between 2.5 and 6.2 J/cm² exhibited statistically higher viability than that of the groups with small power (5 mW), longer application period (50 s), and radiant exposure of 6.2 J/cm² (p < 0.05). VEGF and FGF-2 mRNA expression were observed at the three evaluated periods (6 h, 12 h, and 24 h) and the highest expression was in the shortest period (p < 0.05). All radiant exposures maintained HPF viable. The period of 6 h after irradiation showed statistically greater gene expression for both growth factors than other periods. VEGF mRNA had no differences among the dosimetries studied. The best radiant exposures for FGF-2 gene expression were 2.5 J/cm² and 3.7 J/cm².

Does the application of GaAlAs laser and platelet-rich plasma induce cell proliferation and increase alkaline phosphatase activity in human dental pulp stem cells?

Blood extracts containing platelet products are gaining popularity in promoting healing and pulp regeneration. This study was designed to evaluate the effect of platelet-rich plasma (PRP) and gallium-aluminum-arsenide (GaAlAs) laser on proliferation and differentiation of human dental pulp stem cells (hDPSCs). In this ex vivo study, hDPSCs isolated from impacted mandibular third molars were cultured in Dulbecco's Modified Eagle's medium )DMEM(with 10% fetal bovine serum (FBS). After reaching the desired confluence, the cells were distributed into 4 groups, namely, control, PRP, laser, and PRP+laser for MTT assay and alkaline phosphatase (ALP) test. In the PRP and PRP+laser groups, 10% PRP was added to each well on the plate. In the laser and PRP+laser groups, as for the proliferation test, laser irradiation was carried out for 45 s, while 135 s was designated for ALP test. After 1, 3, and 5 days, cell proliferation and ALP activity were assessed using MTT and ALP colorimetric assay, respectively. Two-way ANOVA was utilized to analyze data. In PRP and PRP+laser groups, cell proliferation and viability increased until day 3 but began to decline afterwards until the 5th day. In the laser group, the increase in proliferation and viability was observed till day 5 which was less than the control group. Laser and control groups exhibited significantly higher cell viability and proliferation than both PRP and PRP+laser groups. ALP activity was more pronounced in PRP+laser, PRP, and laser in descending order; however, all were less than that of the control group. Only in the control group did the ALP activity augment during the 5-day period. Laser irradiation could induce pulp cell proliferation and demonstrated a better performance than PRP in this regard.

Effects of intravenous and transdermal photobiomodulation on the postoperative complications of coronary artery bypass grafting surgery: a randomized, controlled clinical trial

Although coronary artery bypass graft (CABG) surgery is one of the most worldwide commonly performed cardiac surgeries to enhance myocardial perfusion in high-grade myocardial occlusion, it remains a high-risk procedure. Photobiomodulation (PBM) is one of the methods which have been shown to have positive effects on the healing process after CABG and postoperative complications. The aim of this study was to evaluate the efficacy of PBM in patients who underwent a coronary artery bypass graft (CABG). Ths study was conducted with 192 volunteers who electively submitted to CABG. The volunteers were randomly allocated into two groups: laser-treated (transdermal: 980 nm, 200 mW, continuous, average energy fluency of 6 J/cm² and intravenous: 405 nm, 1.5 mW, continuous for 30 min) and standard treatment and control group (standard treatment only). Intravenous laser was illuminated the day before the surgery, immediately after transferring the patient to CCU post-operation and IV laser in addition to transdermal laser was applied every day after surgery for 6 days. A total of 170 out of 192 participants completed the study, 82 (48.2%) in the PBM group and 88 (51.8%) in the control group. Level of LDH and CPK was significantly lower in the PBM group (P < 0.05) in the 4th day postoperatively. The PBM group also showed significantly lower post-surgery complications, including pericardial effusion, ejection fraction, pathologic ST changes, pathologic Q, rehospitalization, heart failure, and mediastinitis (P < 0.05). Likewise, the VAS pain score after surgery was significantly lower in patients in the laser group (P < 0.05). PBM seems a promising, safe, cost-benefit therapeutic modality to reduce postoperative complications of CABG. Trial registration number: IRCT2016052926069N4 .

Evaluation of the Efficacy of Ultrapulsed CO2 Laser in Chronic Wounds

BACKGROUND AND OBJECTIVES

Chronic wound repair is a major problem in wound treatment. Recently, several studies have suggested that carbon dioxide (CO₂ ) laser can be used to improve the healing of chronic wounds. The aim of the present study was to preliminarily investigate the efficacy of laser debridement in treating chronic wound through a comparison of traditional instrument/surgical debridement with the ultrapulsed CO₂ laser debridement in terms of wound healing, wound infection control, and wound blood perfusion.

STUDY DESIGN/MATERIALS AND METHODS

Patients with chronic wound admitted to the Wound Repair Clinic at The Affiliated Hospital of Southwest Medical University (Luzhou, China) between February 2019 and May 2019 were enrolled. They were randomly divided into two groups. The patients in one group were treated with traditional sharp instrument/surgical debridement (RT group; number of wounds: 28), while the patients in the other group were treated with ultrapulsed CO₂ laser debridement (LT group; number of wounds: 26). An intergroup comparison was performed based on parameters, such as wound healing, wound infection control, and changes in wound blood perfusion.

RESULTS

The wound healing rate and the total time to achieve healing were significantly better in the LT group versus the RT group at 7, 14, 21, and 28 days after treatment. The wound exudation scores were significantly higher in the LT group versus the RT group at 7, 14, and 28 days after treatment. The positive rate of pre-debridement bacterial culture was significantly lower in the LT group versus the RD group at 14 and 28 days after treatment. The percentage of wound perfusion/normal periwound skin perfusion was significantly higher in the LT group versus the RT group at 1, 7, and 14 days after treatment.

CONCLUSION

For the treatment of chronic refractory wounds, the ultrapulsed CO₂ laser exhibits higher accuracy, more effectively controls wound infection, promotes an increase in wound blood perfusion, and achieves faster wound healing compared with traditional sharp instrument/surgical debridement. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

Photobiomodulation therapy for management of inferior alveolar nerve injury post-extraction of impacted lower third molars

Purpose

Inferior alveolar nerve (IAN) injury is one of the most serious complications after extraction of impacted lower third molars. Photobiomodulation (PBM) therapy has been noted to reduce pain and inflammation while promoting tissue healing. This study examined the efficacy of PBM therapy tested in a case series of patients with postoperative IAN injury.

Material and methods

20 patients with post-extraction IAN injury were involved in this study and divided into two groups. In the study group, PBM therapy (808-nm laser, 16 mW, 3 J/cm²) was used every other day for 2 weeks solely on post-extraction sockets in 10 patients diagnosed with IAN injury. In the control group, mecobalamine was prescribed to 10 patients with IAN injury. Objective and subjective recovery of IAN paresthesia was evaluated using clinical neurosensory testing and visual analog score.

Results

All patients showed improvement in both objective and subjective examination. Notably, the visual analog score was significantly improved after PBM treatment compared to the mecobalamine treatment (p < 0.05).

Conclusion

PBM therapy with 808-nm laser appears to be an effective approach to manage paresthesia post-IAN injury following impacted third molar surgery. Given the limited sample size in this study, large-scale, placebo-controlled, multi-center randomized controlled trials are needed for further validation of this innovative treatment.

Potential Novel Strategies for the Treatment of Dental Pulp-Derived Pain: Pharmacological Approaches and Beyond

The diagnosis and management of pain is an everyday occurrence in dentistry, and its effective control is essential to ensure the wellbeing of patients. Most tooth-associated pain originates from the dental pulp, a highly vascularized and innervated tissue, which is encased within mineralized dentin. It plays a crucial role in the sensing of stimuli from the local environment, such as infections (i.e. dental caries) and traumatic injury, leading to a local inflammatory response and subsequently to an increase in intra-pulp pressure, activating nerve endings. However, thermal, chemical, and mechanical stimuli also have the ability to generate dental pulp pain, which presents mechanisms highly specific to this tissue and which have to be considered in pain management. Traditionally, the management of dental pulp pain has mostly been pharmacological, using non-steroidal anti-inflammatory drugs (NSAIDs) and opioids, or restorative (i.e. removal of dental caries), or a combination of both. Both research areas continuously present novel and creative approaches. This includes the modulation of thermo-sensitive transient receptor potential cation channels (TRP) by newly designed drugs in pharmacological research, as well as the use of novel biomaterials, stem cells, exosomes and physical stimulation to obtain pulp regeneration in regenerative medicine. Therefore, the aim of this review is to present an up-to-date account of causes underlying dental pain, novel treatments involving the control of pain and inflammation and the induction of pulp regeneration, as well as insights in pain in dentistry from the physiological, pharmacological, regenerative and clinical perspectives.