Effect of laser photobiomodulation associated with a bioceramic cement on the repair of bone tissue in the femur of rats

Influence of systemic vitamin D administration and local photobiomodulation on bone repair: Histomorphometric, histochemical, and immunohistochemical study in rat calvaria

OBJECTIVE

The purpose of the present study was to evaluate the influence of systemic vitamin D (Vit D) administration with or without local photobiomodulation (PBM) on bone repair of surgically created critical-size defects (CSD) in rat calvaria.

MATERIAL AND METHOD

Thirty-two rats were used. A 5 mm DTC was created on the calvaria of each animal. The animals were randomly distributed into four experimental groups (n = 8): Control: no treatment; Vit D: systemic Vit D administration through gavage; PBM: local irradiation with low-intensity laser therapy; Vit D/PBM: systemic Vit D administration through gavage and local irradiation with low-intensity laser therapy. The animals were euthanized 15 days after treatments. It was evaluated newly formed bone area (NFBA), percentage of mature and immature collagen fibers (picrosirius red staining and polarized light), immunohistochemical identification of tartrate-resistant acid phosphatase (TRAP), transforming growth factor (TGF), and osteocalcin (OCN). Data were statistically analyzed (ANOVA, Kruskal-Wallis, p < 0.05).

RESULTS

All experimental groups presented similar statistical results in the evaluated parameters. Some qualitative differences were observed, as follows. Groups PBM, Vit D, and Vit D/ PBM presented a slight amount of newly formed bone. Group Vit D presented a higher amount of mature collagen fibers. Groups Vit D and PBM presented higher immunoexpression of OCN than other experimental groups.

CONCLUSION

It can be concluded that Vit D and PBM did not significantly increase the amount of bone tissue formed but showed a trend towards enhanced bone maturation in the early healing stages of critical-sized defects surgically created in rat calvaria.

Calcium Hydroxyapatite Combined with Photobiomodulation for Bone Tissue Repair: A Systematic Review

Repairing hard tissues, such as bones, remains a significant challenge, especially in adverse clinical conditions. Calcium hydroxyapatite (CaHA), a calcium phosphate (CaP), has structural and chemical characteristics similar to the mineral structure of human bones and teeth, offering bioactivity and biocompatibility properties. Photobiomodulation (PBM) uses light to reduce inflammation and accelerate tissue healing. This systematic review analyzes the combination of CaHA and PBM from 25 studies extracted from the PubMed, Web of Science, and ScienceDirect databases, using the keywords "hydroxyapatite AND photobiomodulation", "calcium hydroxyapatite AND photobiomodulation", and "low-level laser therapy AND calcium phosphate." All studies focused on bone regeneration, with no mention of soft tissue applications. The most commonly used calcium-based material was biphasic calcium phosphate (76%), a combination of CaHA and β-tricalcium phosphate, while 16% of the studies did not specify the brand or product used. With regard to PBM, the most commonly used wavelengths (48% of cases, with a tie of 24% for each) were infrared lasers at 808 nm and 780 nm, with 20% of studies not mentioning the brand or manufacturer. The results underscore the predominant focus on bone regeneration, highlighting the need for further investigations into soft tissue applications and the establishment of standardized protocols. The combination of CaHA and PBM shows promise in regenerative medicine and dentistry, although more research is needed to expand its experimental and clinical use.

Evaluating the Therapeutic Potential of Microneedle Patch Laser With Multiple Wavelengths in Allergic Rhinitis: Insights From an Allergic Rhinitis Mouse Model

OBJECTIVE

There is insufficient evidence to determine the effectiveness of treating allergic rhinitis with a patch laser affix to the skin as opposed to direct intranasal irradiation of the nasal mucosa. We aimed to evaluate the effect of the microneedle patch laser with multiple wavelengths in an allergic rhinitis (AR) mouse model and its underlying mechanism.

METHODS

The microneedle patch laser was attached to the skin above the mouse's nasal cavity, transmitting light to the nasal mucosa. For 10 days, the microneedle patch laser administered simultaneous exposure to wavelengths of 670, 780, 850, and 910 nm at either 10 or 20 min each day. Multiple allergic parameters were evaluated following the microneedle patch laser treatment.

RESULTS

Microneedle patch laser treatment decreased allergic symptoms and inhibited OVA-specific IgE levels. Additionally, it significantly reduced eosinophil infiltration, epithelial thickness of the nasal mucosa, and IL-4 cytokine levels.

CONCLUSION

The light emitted by the microneedle patch laser attached to the skin, penetrated effectively to the nasal mucosa within the nasal cavity, suggesting potential for treating allergic rhinitis in mice and could be extended in clinical applications.

Tailoring photobiomodulation to enhance tissue regeneration

Photobiomodulation (PBM), the use of biocompatible tissue-penetrating light to interact with intracellular chromophores to modulate the fates of cells and tissues, has emerged as a promising non-invasive approach to enhancing tissue regeneration. Unlike photodynamic or photothermal therapies that require the use of photothermal agents or photosensitizers, PBM treatment does not need external agents. With its non-harmful nature, PBM has demonstrated efficacy in enhancing molecular secretions and cellular functions relevant to tissue regeneration. The utilization of low-level light from various sources in PBM targets cytochrome c oxidase, leading to increased synthesis of adenosine triphosphate, induction of growth factor secretion, activation of signaling pathways, and promotion of direct or indirect gene expression. When integrated with stem cell populations, bioactive molecules or nanoparticles, or biomaterial scaffolds, PBM proves effective in significantly improving tissue regeneration. This review consolidates findings from in vitro, in vivo, and human clinical outcomes of both PBM alone and PBM-combined therapies in tissue regeneration applications. It encompasses the background of PBM invention, optimization of PBM parameters (such as wavelength, irradiation, and exposure time), and understanding of the mechanisms for PBM to enhance tissue regeneration. The comprehensive exploration concludes with insights into future directions and perspectives for the tissue regeneration applications of PBM.

The role of photobiomodulation in accelerating bone repair

Bone repair is faced with obstacles such as slow repair rates and limited bone regeneration capacity. Delayed healing even nonunion could occur in bone defects, influencing the life quality of patients severely. Photobiomodulation (PBM) utilizes different light sources to derive beneficial therapeutic effects with the advantage of being non-invasive and painless, providing a promising strategy for accelerating bone repair. In this review, we summarize the parameters, mechanisms, and effects of PBM regulating bone repair, and further conclude the current clinical application of PBM devices in bone repair. The wavelength of 635-980 nm, the output power of 40-100 mW, and the energy density of less than 100 J/cm2 are the most commonly used parameters. New technologies, including needle systems and biocompatible and implantable optical fibers, offer references to realize an efficient and safe strategy for bone repair. Further research is required to establish the reliability of outcomes from in vivo and in vitro studies and to standardize clinical trial protocols.

The effect of photobiomodulation therapy in common maxillofacial injuries: Current status

The use of photobiomodulation therapy (PBMT) may be used for treating trauma to the maxillofacial region. The effects of PBMT on maxillofacial injuries were discussed in this review article. The electronic databases Pubmed, Scopus, and Web of Science were thoroughly searched. This review included in vitro, in vivo, and clinical studies describing how PBMT can be used in maxillofacial tissue engineering and regenerative medicine. Some studies suggest that PBMT may offer a promising therapy for traumatic maxillofacial injuries because it can stimulate the differentiation and proliferation of various cells, including dental pulp cells and mesenchymal stem cells, enhancing bone regeneration and osseointegration. PBMT reduces pain and swelling after oral surgery and tooth extraction in human and animal models of maxillofacial injuries. Patients with temporomandibular disorders also benefit from PBMT in terms of reduced inflammation and symptoms. PBMT still has some limitations, such as the need for standardizing parameters. PBMT must also be evaluated further in randomized controlled trials in various maxillofacial injuries. As a result, PBMT offers a safe and noninvasive treatment option for patients suffering from traumatic maxillofacial injuries. PBMT still requires further research to establish its efficacy in clinical practice and determine the optimal parameters.

Can Collagen Membrane on Bone Graft Interfere with Light Transmission and Influence Tissue Neoformation During Photobiomodulation? A Preliminary Study

Objective: This study qualitatively and quantitatively evaluated the transmission of light through a collagen membrane and the consequent local bone formation in a critical bone defect in vitro and in an animal model. Background: Currently, bone substitutes and collagen membranes are used to promote new bone formation; however, when associated with photobiomodulation, biomaterials can act as a barrier, hindering the passage of light radiation to the area to be treated. Methods: Light transmittance was evaluated in vitro with a power meter and a 100 mW, 808 nm laser source with and without membrane. Twenty-four male rats received a critical surgical defect of 5 mm in diameter in the calvarial bone, subsequently a biomaterial (Bio-Oss; Geistlich®, Switzerland) was applied, and the animals were divided into the following three groups: G1-collagen membrane and no irradiation; G2-collagen membrane and photobiomodulation (irradiation with 4 J of 808 nm); and G3-photobiomodulation (4 J) followed by a collagen membrane. Histomophometric analyses were performed at 7 and 14 days after euthanasia. Results: The membrane reduced the light transmittance (808 nm) by an average of 78%. Histomophometric analyses showed significant differences in new blood vessels on day 7 and bone neoformation on day 14. Irradiation without membrane interposition resulted in a 15% more neoformed bone compared with the control (G1), and 6.5% more bone compared with irradiation over the membrane (G2). Conclusions: The collagen membrane interferes with light penetration during photobiomodulation, decreases light dosimetry on the wound area, and interferes with bone neoformation.

Effects of a Biocomplex Formed by Two Scaffold Biomaterials, Hydroxyapatite/Tricalcium Phosphate Ceramic and Fibrin Biopolymer, with Photobiomodulation, on Bone Repair

There are several treatment methods available for bone repair, although the effectiveness becomes limited in cases of large defects. The objective of this pre-clinical protocol was to evaluate the grafting of hydroxyapatite/tricalcium phosphate (BCP) ceramic biomaterial (B; QualyBone BCP®, QualyLive, Amadora, Portugal) together with the heterologous fibrin biopolymer (FB; CEVAP/UNESP Botucatu, Brazil) and with photobiomodulation (PBM; Laserpulse®, Ibramed, Amparo, Brazil) in the repair process of bone defects. Fifty-six rats were randomly divided into four groups of seven animals each: the biomaterial group (G1/B), the biomaterial plus FB group (G2/BFB); the biomaterial plus PBM group (G3/B + PBM), and the biomaterial plus FB plus PBM group (G4/BFB + PBM). After anesthesia, a critical defect was performed in the center of the rats' parietal bones, then filled and treated according to their respective groups. The rats were euthanized at 14 and 42 postoperative days. Histomorphologically, at 42 days, the G4/BFB + PBM group showed a more advanced maturation transition, with more organized and mature bone areas forming concentric lamellae. A birefringence analysis of collagen fibers also showed a more advanced degree of maturation for the G4/BFB + PBM group. In the comparison between the groups, in the two experimental periods (14 and 42 days), in relation to the percentage of formation of new bone tissue, a significant difference was found between all groups (G1/B (5.42 ± 1.12; 21.49 ± 4.74), G2/BFB (5.00 ± 0.94; 21.77 ± 2.83), G3/B + PBM (12.65 ± 1.78; 29.29 ± 2.93), and G4/BFB + PBM (12.65 ± 2.32; 31.38 ± 2.89)). It was concluded that the use of PBM with low-level laser therapy (LLLT) positively interfered in the repair process of bone defects previously filled with the biocomplex formed by the heterologous fibrin biopolymer associated with the synthetic ceramic of hydroxyapatite and tricalcium phosphate.

The Signalling Effects of Photobiomodulation on Osteoblast Proliferation, Maturation and Differentiation: A Review

Proliferation of osteoblasts is essential for maturation and mineralization of bone matrix. Ossification, the natural phase of bone-forming and hardening is a carefully regulated phase where deregulation of this process may result in insufficient or excessive bone mineralization or ectopic calcification. Osteoblasts can also be differentiated into osteocytes, populating short interconnecting passages within the bone matrix. Over the past few decades, we have seen a significant improvement in awareness and techniques using photobiomodulation (PBM) to stimulate cell function. One of the applications of PBM is the promotion of osteoblast proliferation and maturation. PBM research results on osteoblasts showed increased mitochondrial ATP production, increased osteoblast activity and proliferation, increased and pro-osteoblast expression in the presence of red and NIR radiation. Osteocyte differentiation was also accomplished using blue and green light, showing that different light parameters have various signalling effects. The current review addresses osteoblast function and control, a new understanding of PBM on osteoblasts and its therapeutic impact using various parameters to optimize osteoblast function that may be clinically important. Graphical Abstract.

New Bioactive Calcium Silicate Cement Mineral Trioxide Aggregate Repair High Plasticity (MTA HP)-A Systematic Review

Bioactive calcium silicate cement Mineral Trioxide Aggregate (MTA) has been used for years as a gold standard in intravital pulp treatment and specialist endodontic procedures. Owing to flaws of the material, the manufacturers have been trying to enhance and produce materials showing improved physical, chemical and biological parameters. One of the new calcium-silicate cements based on mineral trioxide aggregate, however without some flaws exhibited by the cement, is Mineral Trioxide Aggregate Repair High Plasticity (MTA HP). The aim of the present paper was a systematic literature review concerning the MTA HP material used nowadays in dentistry, as a review of its specific features. The present paper is the first article providing a systematic literature review on MTA HP. The aim of the present article is the better understanding of MTA HP properties, which can aid the decision-making process in endodontic treatment.