Oral wound healing models and emerging regenerative therapies

A Bilayer Polyurethane Patch with Sustained Growth Factor Release and Antibacteria for Re-epithelization of Large-Scale Oral Mucosal Defects

In the field of oral and maxillofacial surgery, extensive oral soft-tissue injuries occur repeatedly in clinical practice; however, effective restorative materials are lacking. In this study, a biodegradable waterborne polyurethane patch featuring a mucosa bionic bilayer structure is presented. This patch consists of a porous scaffold layer that faces the lesion, incorporating a polydopamine coating to achieve sustained release of epidermal growth factors (EGFs) for mucosal defect reconstruction. Additionally, there is a dense barrier layer toward the oral cavity loaded with silver nanoparticles, which prevents bacteria from entering the wound and simultaneously acts as a physical barrier. This patch can sustainably release EGF in vitro for 2 weeks, thereby facilitating the proliferation and migration of HaCaT and L929 cells, while effectively killing common oral cavity bacteria. In a rabbit buccal mucosal full-thickness defect model, the patch demonstrates better efficacy than the clinical benchmark, decellularized extracellular matrix (dECM). It effectively reduces wound inflammation and significantly upregulates gene expression associated with epithelialization by activating the EGF/epidermal growth factor receptor (EGFR) pathway. These mechanisms promote the proliferation, differentiation, and migration of epithelial/keratinocyte cells, ultimately expediting mucosal defect healing and wound closure.

Immediate but Temporal Response: The Role of Distal Epithelial Cells in Wound Healing

Efficient oral mucosal wound healing requires coordinated responses from epithelial progenitor cells, yet their spatiotemporal recruitment and activation remain unclear. Using a mouse model of palatal mucosal wound healing, we investigated the dynamics of epithelial cells during this process. Proliferation analysis revealed that, in addition to the expected proliferation center near the wound edge, distal cell populations rapidly activated post-injury by elevating their mitotic activity. These distal cells displayed predominant lateral expansion in the basal layer, suggesting roles beyond just tissue renewal. However, while proximal proliferation center cells sustained heightened proliferation until re-epithelialization was completed, distal cells restored basal turnover rates before wound closure, indicating temporally confined contributions. Lineage tracing of Wnt-responsive epithelial cells showed remarkable clone expansion in basal layers both proximally and distally after wounding, contrasting with gradual clone expansion in homeostasis. Although prioritizing tissue repair, epithelial progenitor cells maintained differentiation programs and barrier functions, with the exception of the leading edge. At the leading edge, we found accelerated cell turnover, but the differentiation program was suspended. In summary, our findings uncovered that oral wound re-epithelialization involves two phases: an initial widespread response with proliferation of proximal and distal cells, followed by proliferation confined to the wound proximal region. Uncovering these stage-specific healing mechanisms provides insights for developing targeted therapeutic strategies to improve wound care.

Oral host-microbe interactions investigated in 3D organotypic models

The oral cavity is inhabited by abundant microbes which continuously interact with the host and influence the host's health. Such host-microbe interactions (HMI) are dynamic and complex processes involving e.g. oral tissues, microbial communities and saliva. Due to difficulties in mimicking the in vivo complexity, it is still unclear how exactly HMI influence the transition between healthy status and disease conditions in the oral cavity. As an advanced approach, three-dimensional (3D) organotypic oral tissues (epithelium and mucosa/gingiva) are being increasingly used to study underlying mechanisms. These in vitro models were designed with different complexity depending on the research questions to be answered. In this review, we summarised the existing 3D oral HMI models, comparing designs and readouts, discussing applications as well as future perspectives.

Periodontal granulation tissue - To remove or not to remove, that is the question

Formation of granulation tissue is a fundamental phase in periodontal wound healing with subsequent maturation leading to regeneration or repair. However, persistently inflamed granulation tissue presents in osseous defects as a result of periodontitis and is routinely disrupted and discarded with non-surgical and surgical therapy to facilitate wound healing or improve chances of regeneration. Histological assessment suggests that granulation tissue from periodontitis-affected sites is effectively a chronic inflammatory tissue resulting from impaired wound healing due to persistence of bacterial dysbiotic bioflim. Nevertheless, the immunomodulatory potential and stem cell characteristics in granulation tissue have also raised speculation about the tissue's regenerative potential. This has led to the conception and recent implementation of surgical techniques which preserve granulation tissue with the intention of enhancing innate regenerative potential and improve clinical outcomes. As knowledge of fundamental cellular and molecular functions regulating periodontitis-affected granulation tissue is still scarce, this review aimed to provide a summary of current understanding of granulation tissue in the context of periodontal wound healing. This may provide new insights into clinical practice related to the management of granulation tissue and stimulate further investigation.

Combinatorial effects of hydroxyapatite and Tualang honey on medication-related osteonecrosis of the jaw (MRONJ): An in vitro study

BACKGROUND

Medication-related osteonecrosis of the jaw (MRONJ) is a severe complication associated with prolonged bisphosphonate therapy. Increasing evidence shows that mucosal damage plays an important role in the pathogenesis of MRONJ. This study investigates the combinatorial effects of hydroxyapatite with Tualang honey on cell viability and wound healing in MRONJ.

MATERIALS AND METHODS

The incorporation of Tualang honey into hydroxyapatite was assessed using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and field emission scanning electron-energy dispersive X-ray analysis microscopy (FESEM-EDX). The effect of hydroxyapatite combined with Tualang honey on cell viability was determined by WST-1 assay and wound healing was assessed by scratch assay.

RESULTS

The incorporation of Tualang honey into hydroxyapatite altered the functional groups, structure, size, morphology, and components of the crystal as evidenced by FTIR, XRD and FESEM-EDX analysis. High concentrations of pamidronic acid inhibit oral fibroblast viability and wound healing. Low and high concentrations of hydroxyapatite demonstrate non-toxicity towards fibroblast cells. Furthermore, hydroxyapatite reversed the action of pamidronic acid on the cells; it increased fibroblast viability but did not close the wound. Tualang honey promotes fibroblast viability and wound closure. However, the addition of Tualang honey is unable to overcome the inhibitory effects of pamidronic acid on fibroblasts. The addition of Tualang honey and hydroxyapatite improved the cell viability and accelerated wound closure of fibroblast exposed to pamidronic acid.

CONCLUSION

These findings demonstrated that the combination treatment protects oral fibroblasts by preventing bisphosphonate toxicity.

Combined use of hydrogen-rich water and enzyme-digested edible bird's nest improves PMA/LPS-impaired wound healing in human inflammatory gingival tissue equivalents

Gingival wound healing plays a critical role in maintaining oral health. However, this process can be delayed by oxidative stress and excessive inflammatory responses. In this study, we established a human inflammatory gingival tissue equivalent (iGTE) to investigate the inhibitory effects of hydrogen-rich water (HW), enzyme-digested edible bird's nest (EBND) and sialic acid (SA) on PMA (an inducer of oxidative free radicals)- and LPS (an inflammatory stimulus)-impaired wound healing. The iGTE was constructed by human gingival fibroblasts (hGFs), keratinocytes and macrophages under three-dimensional conditions. Wounds in the iGTE and hGF/keratinocyte monolayers were created by mechanical injury. Tissues and cells were pretreated with HW, EBND, and SA, and then exposed to the inflammatory and oxidative environment induced by PMA (10 ng/mL) and LPS (250 ng/mL). The inflammatory cytokines IL-6 and IL-8 were quantitatively analyzed by ELISA. Histopathological image analysis was performed by HE and immunofluorescence staining. In the iGTE, PMA/LPS significantly reduced the epithelial thickness while causing a decrease in K8/18, E-cadherin, laminin and elastin expression and an increase in COX-2 expression along with ulcer-like lesions. In mechanically scratched hGFs and keratinocyte monolayers, PMA/LPS significantly impaired wound healing, and promoted the secretion of IL-6 and IL-8. Pretreatment of HW, EBND, and SA significantly suppressed PMA/LPS-induced wound healing delay and inflammatory responses in cell monolayers, as well as in the iGTE. Remarkably, the combined use of HW and EBND exhibited particularly robust results. Combined use of HW and EBND may be applied for the prevention and treatment of wound healing delay.

Dynamic characterization of vascular response and treatment in oral traumatic ulcer in mice via photoacoustic imaging

Background

Dynamic surveillance of vasculature is essential for evaluating the healing of oral ulcer. Existing techniques used in vascular imaging face limitations, such as inadequate spatial resolution, restricted diagnostic depth, and the necessity of exogenous contrast agents. Therefore, this study aimed to use robust photoacoustic imaging (PAI) for the dynamic monitoring of vascular response during healing and the associated treatment process of oral ulcer.

Methods

Kunming mice (male, 8 weeks old, 31-41 g) were treated with 50% acetic acid for 90 s on the tongue mucosa for induction of oral traumatic ulcer. Mice were randomly divided into three groups (n=12): the control, compound chamomile and lidocaine hydrochloride gel (CCLH), and phycocyanin (PC) groups. PAI was then conducted on days 0, 2, 3, 5, and 7 to obtain vessel parameters of the ulcer area, including vessel intensity, density, mean diameter, maximum diameter, and curvature. Immunohistochemical and hematoxylin and eosin (HE) staining were performed on days 3 and 7 to assess microvessel density and inflammation score. The ulcer healing rate and body weight changes were evaluated for clinical observation.

Results

Beginning on the second day after ulcer induction, there was a progressive increase over time in blood intensity and vessel parameters, including vascular density and diameter. On day 7, the CCLH and PC groups demonstrated significantly higher measures than did the control group in terms of blood intensity (P<0.05 and P<0.01), vascular density (both P values <0.05), mean diameter (both P values <0.01), and maximum diameter (P<0.01 and P<0.05). Vessel curvature in the two treatment groups exhibited no significant differences compared to that in the control group (both P values >0.05). The effects of vascular morphological changes were further supported by the histological and clinical outcomes. On day 7, compared to that of the control group, the level of microvessel density was significantly higher in both the CCLH (P<0.01) and PC (P<0.05) groups. The histopathological score in PC group was significantly lower than that of the control group on day 7 (P<0.05). Additionally, compared to that of the control group, the healing rates of the CCLH (P<0.01) and PC groups (P<0.05) were superior on day 7. On day 3, the control group showed more weight loss than did the CCLH (P<0.05) and PC (P<0.01) groups.

Conclusions

These findings indicate that PAI is a valuable strategy for the dynamic and quantitative analysis of vascular alterations in oral traumatic ulcers and support its prospective application in improving clinical treatment.

General Semi-Solid Freeze Casting for Uniform Large-Scale Isotropic Porous Scaffolds: An Application for Extensive Oral Mucosal Reconstruction

Ice-templated porous biomaterials possess transformative potential in regenerative medicine; yet, scaling up ice-templating processes for broader applications-owing to inconsistent pore formation-remains challenging. This study reports an innovative semi-solid freeze-casting technique that draws inspiration from semi-solid metal processing (SSMP) combined with ice cream-production routines. This versatile approach allows for the large-scale assembly of various materials, from polymers to inorganic particles, into isotropic 3D scaffolds featuring uniformly equiaxed pores throughout the centimeter scale. Through (cryo-)electron microscopy, X-ray tomography, and finite element modeling, the structural evolution of ice grains/pores is elucidated, demonstrating how the method increases the initial ice nucleus density by pre-fabricating a semi-frozen slurry, which facilitates a transition from columnar to equiaxed grain structures. For a practical demonstration, as-prepared scaffolds are integrated into a bilayer tissue patch using biodegradable waterborne polyurethane (WPU) for large-scale oral mucosal reconstruction in minipigs. Systematic analyses, including histology and RNA sequencing, prove that the patch modulates the healing process toward near-scarless mucosal remodeling via innate and adaptive immunomodulation and activation of pro-healing genes converging on matrix synthesis and epithelialization. This study not only advances the field of ice-templating fabrication but sets a promising precedent for scaffold-based large-scale tissue regeneration.

Topical Adipose Mesenchymal Stem cell metabolites regulate the expression of MMP-1, MMP-9, EGF, TGF-β in oral mucosa ulcer rat model

Objective

Matrix metalloproteinase (MMP-1 and -9), Epidermal Growth Factor (EGF), and Transforming Growth factor (TGF)-β are expressed in the oral ulcer wound-healing process. The Adipose mesenchymal stem cell metabolites (AdMSCMs) may accelerate wound-healing. This study aimed to investigate the expression of MMP-1, MMP-9, EGF, and TGF-β in the oral mucosa ulcer rat model treated with topical AdMSCMs.

Materials and Methods

Oral ulcer models were created in twenty healthy male Wistar rats (Rattus novergicus) divided into AdMSCMs and control groups. The oral ulcer model was treated topically using AdMSCMs oral gel three times daily for 3 and 7 days. The expression of MMP-1, MMP-9, EGF, TGF-β was evaluated through histological examination using the immunohistochemistry method. Independent t-test was used to compare the mean of expression of MMP-1, MMP-9, EGF, TGF-β between control and treatment groups (AdMSCMs), and paired t-test was used to analyze the mean between day 3 and day 7 of each group.

Results

A lower expression of MMP-1, MMP-9 in AdMSCMs group and higher expression EGF and TGF-β in AdMSCMs group compared to the control group in day 3 and day 7. Independent t-test results showed a significant difference in the expression of MMP-1, MMP-9, EGF between the control and AdMSCMs group in day 3 and day 7. Only TGF-β expression mean difference between day 3 and day 7 showed a significant difference compared to the control groups (p < 0.05).

Conclusions

AdMSCMs oral gel may accelerate oral ulcer healing models by reducing the expression MMP-1, MMP-9, and increasing EGF and TGF-β expressions during the wound-healing process.

From Short Circuit to Completed Circuit: Conductive Hydrogel Facilitating Oral Wound Healing

The primary challenges posed by oral mucosal diseases are their high incidence and the difficulty in managing symptoms. Inspired by the ability of bioelectricity to activate cells, accelerate metabolism, and enhance immunity, a conductive polyacrylamide/sodium alginate crosslinked hydrogel composite containing reduced graphene oxide (PAA-SA@rGO) is developed. This composite possesses antibacterial, anti-inflammatory, and antioxidant properties, serving as a bridge to turn the "short circuit" of the injured site into a "completed circuit," thereby prompting fibroblasts in proximity to the wound site to secrete growth factors and expedite tissue regeneration. Simultaneously, the PAA-SA@rGO hydrogel effectively seals wounds to form a barrier, exhibits antibacterial and anti-inflammatory properties, and prevents foreign bacterial invasion. As the electric field of the wound is rebuilt and repaired by the PAA-SA@rGO hydrogel, a 5 × 5 mm2 wound in the full-thickness buccal mucosa of rats can be expeditiously mended within mere 7 days. The theoretical calculations indicate that the PAA-SA@rGO hydrogel can aggregate and express SOX2, PITX1, and PITX2 at the wound site, which has a promoting effect on rapid wound healing. Importantly, this PAA-SA@rGO hydrogel has a fast curative effect and only needs to be applied for the first three days, which significantly improves patient satisfaction during treatment.

Novel Functional Dressing Materials for Intraoral Wound Care

Intraoral wounds represent a particularly challenging category of mucosal and hard tissue injuries, characterized by the unique structures, complex environment, and distinctive healing processes within the oral cavity. They have a common occurrence yet frequently inflict significant inconvenience and pain on patients, causing a serious decline in the quality of life. A variety of novel functional dressings specifically designed for the moist and dynamic oral environment have been developed and realized accelerated and improved wound healing. Thoroughly analyzing and summarizing these materials is of paramount importance in enhancing the understanding and proficiently managing intraoral wounds. In this review, the particular processes and unique characteristics of intraoral wound healing are firstly described. Up-to-date knowledge of various forms, properties, and applications of existing products are then intensively discussed, which are categorized into animal products, plant extracts, natural polymers, and synthetic products. To conclude, this review presents a comprehensive framework of currently available functional intraoral wound dressings, with an aim to provoke inspiration of future studies to design more convenient and versatile materials.

Early feeding after free flap reconstruction of the oral cavity: A systematic review and meta-analysis

BACKGROUND

Traditionally, patients undergoing free flap reconstruction for oral cavity defects have been given nothing by mouth for 6-14 days post-operatively due to concern for orocutaneous fistula development.

METHODS

Multiple databases were screened for studies assessing the rate of orocutaneous fistula formation in early (≤5 days) versus late (>5 days) feeding groups following oral cavity free flap reconstruction. Fixed- and random-effects meta-analyses were used.

RESULTS

One randomized controlled trial, one prospective cohort, and three retrospective cohort studies were included. The early feeding group displayed no significant increase in orocutaneous fistula formation (RD = -0.02, p = 0.06) or free flap failure (RD = -0.01, p = 0.39), with a significantly shorter hospital length of stay (mean difference [days] = -2.43, p < 0.01).

CONCLUSIONS

While further prospective trials are necessary, initiation of oral intake before post-operative day 5 may be appropriate in properly selected patients following oral reconstruction.

In Vitro Study of Tensile Strength Comparison of Selected Nonabsorbable and Absorbable Suture Materials after Immersion in 0.12% Chlorhexidine Gluconate

Aim

To compare the tensile strength (TS) of absorbable and nonabsorbable suture materials after immersion in 0.12% chlorhexidine gluconate.

Materials and Methods

Six 4-0-gauge suture materials were used, namely silk (S), polypropylene (PP), polyamide 6 (PA6), polyglactin 910 (PG910), poliglecaprone 25 (PL25), and polydioxanone (PDX). A total of 540 suture materials were divided equally (90) into six groups and tested. These materials were divided into a nonimmersed condition (10) and two thermostatically controlled immersion media (40 each), using artificial saliva for the control group (CG) and 0.12% chlorhexidine gluconate for the test group (TG). The specimens were tied to prefabricated rubber rods before immersion and removed at the testing timepoint. By using a universal testing machine (Instron 5566) with hooks attached, a hook-mounted specimen TS testing was performed on days 0, 1, 3, 7, and 14 at a 10 mm/min crosshead speed until the material was stretched to failure, and the maximum TS was recorded in Newtons (N). The continuous variables were taken as the mean and standard deviation across the six study groups to assess the significance at α = 0.05. A two-factor analysis of variance (ANOVA) was performed to assess the TSs over time in different media. A Bonferroni correction was performed when the data were statistically significant according to a two-factor ANOVA. Intragroup statistical comparisons were performed by repeated ANOVA for each study group. All data were analyzed using SPSS 26.

Results

The suture material TS analysis showed that nonabsorbable suture materials maintained their TS throughout the study; silk exhibited different behaviors, decreasing in TS from baseline to day 1 and maintaining its TS until day 14. All absorbable suture materials decreased in TSs by day 14. The silk and PG910 samples in the TG performed significantly better than those in the CG.

Conclusions

Prescribing 0.12% chlorhexidine gluconate as a postsurgical mouth rinse is safest when silk and PG910 are the optimal suture materials.

Early swallowing training after free flap surgery in oral cancer: A randomized controlled trial

OBJECTIVE

To explore the effect of early swallowing training on postoperative outcomes of patients who had undergone oral cancer surgery plus free flap reconstruction.

SUBJECTS AND METHODS

In this prospective, randomized controlled trial, 121 patients who had undergone oral cancer surgery plus free flap reconstruction were randomly assigned to the control (n = 59) or intervention group (n = 62). The control group underwent routine nursing measures. The intervention group received swallowing training on the sixth postoperative day. On the 15th day and 1 month after surgery, the swallowing function (Mann Assessment of Swallowing Ability-Oral Cancer [MASA-OC] score), weight loss rate, time of nasogastric tube removal, and quality of life were evaluated.

RESULTS

Patients in the intervention group had higher MASA-OC scores and better weight loss rates than those in the control group on the 15th day (MASA-OC: p = 0.014, weight loss: p < 0.001) and 1 month (both p < 0.001) after surgery. The time of nasogastric tube removal and the quality of life was statistically significant between groups (p < 0.001).

CONCLUSION

Early swallowing training improves the swallowing function, nutritional status, and quality of life and shortens the indwelling time of nasogastric tube of patients who have undergone oral cancer surgery plus free flap reconstruction.

Ethanolic extract of Gracilaria spp. Attenuates the inflammatory stage of oral mucosa wound healing: An in vivo study

Millions of bacteria present in the mouth cavity contribute to the challenging management of oral mucosa injury. On the other hand, Gracilaria spp. (red algae) is one of the widely cultivated algae that have a strong potential as a wound-healing agent for oral mucosa injury. This study aimed to investigate the wound-healing property of the red algae by observing its effect on polymorphonuclear (PMN), a neutrophil that is usually recruited during the initial wound healing. The extract was obtained through maceration and used as bioactive ingredient in gel preparation. Rattus norvegicus with incision wounds in the oral mucosa was used as the animal model. Our results revealed that rats treated with the red algae gel had significantly lower PMN on the injury site (P < 0.01) as observed on days 1, 3, and 5. Identification using gas chromatography-mass spectrometry showed that the extract was rich in hexadecenoic acid and glycerol. The brine shrimp lethality test suggested low cytotoxicity of this extract with LC50 = 10694.93 mg/mL. In conclusion, the extract could be potentially used as bioactive ingredient in gel formulation for topical management of oral mucosa wounds. Further, research to confirm these findings is warranted.

Adhesive hydrogel releases protocatechualdehyde-Fe3+ complex to promote three healing stages for accelerated therapy of oral ulcers

Oral ulcers can significantly reduce the life quality of patients and even lead to malignant transformations. Local treatments using topical agents are often ineffective because of the wet and dynamic environment of the oral cavity. Current clinical treatments for oral ulcers, such as corticosteroids, have limitations and side effects for long-term usage. Here, we develop adhesive hydrogel patches (AHPs) that effectively promote the healing of oral ulcers in a rat model. The AHPs are comprised of the quaternary ammonium salt of chitosan, aldehyde-functionalized hyaluronic acid, and a tridentate complex of protocatechualdehyde and Fe3+ (PF). The AHPs exhibit tunable mechanical properties, self-healing ability, and wet adhesion on the oral mucosa. Through controlling the formula of the AHPs, PF released from the AHPs in a temporal manner. We further show that the AHPs have good biocompatibility and the capability to heal oral ulcers rapidly. Both in vitro and in vivo experiments indicate that the PF released from AHPs facilitated ulcer healing by suppressing inflammation, promoting macrophage polarization, enhancing cell proliferation, and inducing epithelial-mesenchymal transition involving inflammation, proliferation, and maturation stages. This study provides insights into the healing of oral ulcers and presents an effective therapeutic biomaterial for the treatment of oral ulcers. STATEMENT OF SIGNIFICANCE: By addressing the challenges associated with current clinical treatments for oral ulcers, the development of adhesive hydrogel patches (AHPs) presents an effective approach. These AHPs possess unique properties, such as tunable mechanical characteristics, self-healing ability, and strong adhesion to the mucosa. Through controlled release of protocatechualdehyde-Fe3+ complex, the AHPs facilitate the healing process by suppressing inflammation, promoting cell proliferation, and inducing epithelial-mesenchymal transition. The study not only provides valuable insights into the healing mechanisms of oral ulcers but also introduces a promising therapeutic biomaterial. This work holds significant scientific interest and demonstrates the potential to greatly improve the treatment outcomes and quality of life for individuals suffering from oral ulcers.

One-Step Synthesis of Hydrogel Adhesive with Acid-Responsive Tannin Release for Diabetic Oral Mucosa Defects Healing

The complex preparation, weak wet tissue adhesion, and limited biological activity of traditional oral wound dressings usually impede their efficient treatment and healing for diabetic oral mucosal defects. To overcome these problems, a novel hydrogel adhesive (named CFT hydrogel) is rapidly constructed using a one-step method based on dual-dynamic covalent cross-linking. Compared with the commercial oral patches, the CFT hydrogel shows superior in vivo (rat tongue) wet tissue adhesion performance. Additionally, the CFT hydrogel exhibits unique acid-responsive properties, thereby facilitating the release of bioactive molecule tannic acid in the acidic diabetic wound microenvironment. And a series of in vitro experiments substantiate the favorable biocompatibility and bioactivity properties (including antibacterial, antioxidative, anti-inflammatory, and angiogenetic effects) exhibited by CFT hydrogel. Moreover, in vivo experiments conducted on a diabetic rat model with oral mucosal defects demonstrate that the CFT hydrogel exhibits significant efficacy in protecting against mucosal wounds, alleviating inflammatory reactions, thereby facilitating the wound-healing process. Taken together, this study provides a promising and comprehensive therapeutic option with great potential for the clinical management of oral mucosa defects in diabetic patients.

Green tea and hyaluronic acid gel enhance fibroblast activation and improves the gingival healing post-third molar extraction

This study evaluates the effects of a green tea (Camellia sinensis) and hyaluronic acid gel on fibroblast activity and alveolar bone repair following third molar extractions. By examining the gene expression related to cell survival, proliferation, and angiogenesis, the study bridges in vitro findings with clinical outcomes in a split-mouth randomized trial. Human fibroblasts were exposed to the treatment gel, analysing gene expression through RT-qPCR. Twenty participants undergoing bilateral third molar extractions received the test gel on one side and a placebo on the other. Assessments included patient-reported outcomes, professional evaluations, and radiographic analyses at multiple postoperative intervals. The test gel significantly enhanced AKT, CDKs, and VEGF gene expressions, indicating a positive effect on angiogenesis and cell proliferation. Clinically, it resulted in reduced exudate, swelling, and secondary interventions, with radiographs showing improved alveolar bone density after 90 days. The green tea and hyaluronic acid gel significantly improves soft tissue and bone healing post-extraction, offering a promising adjunctive therapy for enhancing postoperative recovery. This gel represents a novel adjuvant treatment option for facilitating improved healing outcomes after third molar extractions, highlighting its potential utility in clinical dental practice.

Ellagic acid protected the gingival tissue via fibroblast and epidermal growth factors in rats

PURPOSE

To investigate the effect of ellagic acid (EA) in gingival tissues injury in rats.

METHODS

Twenty rats were categorized into two groups. In burn group, an excisional wound area was created by removing a 4-mm diameter flap from the left molar region in the mucoperiosteal region of the gingiva. In burn + ellagic acid group, 1.2 mg/mL EA was administered as irrigation for one week. Animals was sacrificed under anesthesia at the end of experiment. Malondialdehyde (MDA), myeloperoxidase (MPO) and glutathione (GSH) level were measured. Hematoxylin and eosin, fibroblast growth factor (FGF) and epidermal growth factor (EGF) immunostainings were applied to tissues.

RESULTS

MDA, MPO, inflammation and leukocyte infiltration were high in burn group. Degeneration epithelium, edema and inflammatory cell infiltration in connective tissue areas, and dilatation and congestion in blood vessels were observed in burn group. In burn + EA group, the gingival epithelium improved, collagen fiber production increased and organized dermis were observed. After burn injury, FGF and EGF activity was increased in EA treated groups.

CONCLUSIONS

We suggest that EA have the potential for better healing outcomes in oral wounds. EA seems to have promising therapeutic efficacy to enhance oral wound healing.

Revolutionizing Wound Healing: Exploring Scarless Solutions through Drug Delivery Innovations

Human skin is the largest organ and outermost surface of the human body, and due to the continuous exposure to various challenges, it is prone to develop injuries, customarily known as wounds. Although various tissue engineering strategies and bioactive wound matrices have been employed to speed up wound healing, scarring remains a significant challenge. The wound environment is harsh due to the presence of degradative enzymes and elevated pH levels, and the physiological processes involved in tissue regeneration operate on distinct time scales. Therefore, there is a need for effective drug delivery systems (DDSs) to address these issues. The objective of this review is to provide a comprehensive exposition of the mechanisms underlying the skin healing process, the factors and materials used in engineering DDSs, and the different DDSs used in wound care. Furthermore, this investigation will delve into the examination of emergent technologies and potential avenues for enhancing the efficacy of wound care devices.

Hair follicle stem cells promote epidermal regeneration under expanded condition

Skin soft tissue expansion is the process of obtaining excess skin mixed with skin development, wound healing, and mechanical stretching. Previous studies have reported that tissue expansion significantly induces epidermal proliferation throughout the skin. However, the mechanisms underlying epidermal regeneration during skin soft tissue expansion are yet to be clarified. Hair follicle stem cells (HFSCs) have been recognized as a promising approach for epidermal regeneration. This study examines HFSC-related epidermal regeneration mechanisms under expanded condition and proposes a potential method for its cellular and molecular regulation.

Periplaneta americana extract promotes hard palate mucosal wound healing via the PI3K/AKT signaling pathway in male mice

OBJECTIVES

This study aimed to investigate the effect of Periplaneta americana extract, a traditional Chinese medicine, on hard palate mucosal wound healing and explore the underlying mechanisms.

DESIGN

Hard palate mucosal wound model was established and the effects of Periplaneta americana extract on hard palate mucosal wound healing were investigated by stereomicroscopy observation and histological evaluation in vivo. Human oral keratinocytes and human gingival fibroblasts, which play key roles in hard palate mucosal wound healing, were selected as the main research cells in vitro. The effects of Periplaneta americana extract on cell proliferation, migration, and collagen formation were determined by cell counting kit-8 (CCK-8) assay, Transwell assay, and Van Gieson staining. The underlying mechanism was revealed by RNA sequencing, and results were verified by western blot assay.

RESULTS

Stereomicroscopy observation and H&E staining confirmed that Periplaneta americana extract accelerated the healing rate of hard palate mucosal wound (p < 0.001) in vivo. Transwell assay and Van Gieson staining assay showed that Periplaneta americana extract promoted the migration and collagen formation of human oral keratinocytes (p < 0.001) and human gingival fibroblasts (p < 0.001) in vitro. Mechanistically, RNA sequencing and western blot assay demonstrated that Periplaneta americana extract promoted hard palate mucosal wound healing via PI3K/AKT signaling, and the beneficial effects of Periplaneta americana extract were abrogated by the PI3K inhibitor LY294002.

CONCLUSIONS

Periplaneta americana extract shows promising effects for the promotion of hard palate mucosal wound healing and may be a novel candidate for clinical translation.

The Effects of Potato (Solanum tuberosum L. vs. Granola; Solanaceae) Peel Extract Gel on Gingival Wound Healing in Wistar Rats

Purpose

Phenolic compounds with antioxidant, antimicrobial, and anti-inflammatory properties have been identified in potatoes (Solanum tuberosum L.; Solanaceae), which may potentially contribute to wound healing. The study aimed to evaluate the effect of potato peel extract gel Granola variety on oral gingival wound healing in Wistar Rats.

Methods

This research was a true experimental in vivo study, involving 30 male Wistar rats, aged 12-14 weeks and weighing approximately 150 to 200 grams. Surgical vertical incisions, each 3 mm in length, were made on the mandibular gingiva. The test group consisted of six subgroups, each comprising 5 rats. The negative control group received a base gel, while treatment groups were given 1% povidone-iodine solution, 0.1% triamcinolone acetonide oral paste, and 2%, 4%, and 6% potato peel extract gel. Wound lengths were measured on days 3, 7, and 14 to evaluate the healing process. Statistical analysis used the ANOVA test, a p-value of < 0.05 was considered statistically significant.

Results

All experimental groups showed a reduction in wound length on days 3, 7, and 14. Notably, the application of 4% and 6% potato peel extract gel formulations facilitated to faster wound healing on day 3, surpassing the povidone-iodine and triamcinolone acetonide groups. However, by days 7 and 14, both the povidone-iodine group and the 6% formulation group demonstrated superior outcomes, although the differences in values were not statistically significant (p < 0.05).

Conclusion

Potato peel extract gel formulations at 4% and 6% concentrations were found to expedite the healing of incision wounds, showing no statistically significant difference from the povidone-iodine and triamcinolone acetonide groups. Therefore, potato peel extract gel holds excellent potential for development as an alternative medicine for natural and safe wound healing therapy.

Biological processes and factors involved in soft and hard tissue healing

Wound healing is a complex and iterative process involving myriad cellular and biologic processes that are highly regulated to allow satisfactory repair and regeneration of damaged tissues. This review is intended to be an introductory chapter in a volume focusing on the use of platelet concentrates for tissue regeneration. In order to fully appreciate the clinical utility of these preparations, a sound understanding of the processes and factors involved in soft and hard tissue healing. This encompasses an appreciation of the cellular and biological mediators of both soft and hard tissues in general as well as specific consideration of the periodontal tissues. In light of good advances in this basic knowledge, there have been improvements in clinical strategies and therapeutic management of wound repair and regeneration. The use of platelet concentrates for tissue regeneration offers one such strategy and is based on the principles of cellular and biologic principles of wound repair discussed in this review.

Photobiomodulation effects of pulsed and continuous wave near-infrared laser on the proliferation and migration of human gingival fibroblasts: An in vitro study

There are limited data on comparison of pulsed and continuous wave in photobiomodulation therapy (PBM). This study aimed to investigate the effect of PBM with 980 nm laser in pulsed and continuous wave on the proliferation and migration of human gingival fibroblasts (HGF) cells. Cultured HGF were divided into three main groups: (1) irradiated in pulsed mode (frequencies of 50 and 25 KHz; energy densities of 3 and 5 J/cm2 ), (2) irradiated in continuous mode (energy densities of 3.2 and 5.2 J/cm2 ), and (3) no irradiation as control group. HGF proliferation rate was measured by MTT assay at 24, 48, and 72 h post irradiation. In addition, HGF migration rate was measured by scratch test at 24 h post PBM. At 24 h, the group received continuous irradiation at 5.2 J/cm2 showed significantly higher proliferation compared with the control group (p = 0.012). At 48 and 72 h, the groups received continuous, and 50 Hz pulsed irradiation at energy densities of 5.2 and 5 J/cm2 respectively, had significantly higher HGF proliferation rates compared to the control (p < 0.05). Only the continuous irradiations were effective in significant increase of the cell migration. In conclusion, continuous PBM at energy density of 5.2 J/cm2 showed promising effect on HGF proliferation and migration.

Harnessing Bilayer Biomaterial Delivery of FTY720 as an Immunotherapy to Accelerate Oral Wound Healing

Orofacial clefts are the most common craniofacial congenital anomaly. Following cleft palate repair, up to 60% of surgeries have wound healing complications leading to oronasal fistula (ONF), a persistent connection between the roof of the mouth and the nasal cavity. The current gold standard methods for ONF repair use human allograft tissues; however, these procedures have risks of graft infection and/or rejection, requiring surgical revisions. Immunoregenerative therapies present a novel alternative approach to harness the body's immune response and enhance the wound healing environment. We utilized a repurposed FDA-approved immunomodulatory drug, FTY720, to reduce the egress of lymphocytes and induce immune cell fate switching toward pro-regenerative phenotypes. Here, we engineered a bilayer biomaterial system using Tegaderm™, a liquid-impermeable wound dressing, to secure and control the delivery of FTY720- nanofiber scaffolds (FTY720-NF). We optimized release kinetics of the bilayer FTY720-NF to sustain drug release for up to 7d with safe, efficacious transdermal absorption and tissue biodistribution. Through comprehensive immunophenotyping, our results illustrate a pseudotime pro-regenerative state transition in recruited hybrid immune cells to the wound site. Additional histological assessments established a significant difference in full thickness ONF closure in mice on Day 7 following treatment with bilayer FTY720-NF, compared to controls. These findings demonstrate the utility of immunomodulatory strategies for oral wound healing, better positing the field to develop more efficacious treatment options for pediatric patients.

One Sentence Summary

Local delivery of bilayer FTY720-nanofiber scaffolds in an ONF mouse model promotes complete wound closure through modulation of pro-regenerative immune and stromal cells.

Oral administration of Bifidobacterium breve improves anti-angiogenic drugs-derived oral mucosal wound healing impairment via upregulation of interleukin-10

Recent studies have suggested that long-term application of anti-angiogenic drugs may impair oral mucosal wound healing. This study investigated the effect of sunitinib on oral mucosal healing impairment in mice and the therapeutic potential of Bifidobacterium breve (B. breve). A mouse hard palate mucosal defect model was used to investigate the influence of sunitinib and/or zoledronate on wound healing. The volume and density of the bone under the mucosal defect were assessed by micro-computed tomography (micro-CT). Inflammatory factors were detected by protein microarray analysis and enzyme-linked immunosorbent assay (ELISA). The senescence and biological functions were tested in oral mucosal stem cells (OMSCs) treated with sunitinib. Ligated loop experiments were used to investigate the effect of oral B. breve. Neutralizing antibody for interleukin-10 (IL-10) was used to prove the critical role of IL-10 in the pro-healing process derived from B. breve. Results showed that sunitinib caused oral mucosal wound healing impairment in mice. In vitro, sunitinib induced cellular senescence in OMSCs and affected biological functions such as proliferation, migration, and differentiation. Oral administration of B. breve reduced oral mucosal inflammation and promoted wound healing via intestinal dendritic cells (DCs)-derived IL-10. IL-10 reversed cellular senescence caused by sunitinib in OMSCs, and IL-10 neutralizing antibody blocked the ameliorative effect of B. breve on oral mucosal wound healing under sunitinib treatment conditions. In conclusion, sunitinib induces cellular senescence in OMSCs and causes oral mucosal wound healing impairment and oral administration of B. breve could improve wound healing impairment via intestinal DCs-derived IL-10.

Recent trends and perspectives in reconstruction and regeneration of intra/extra-oral wounds using tissue-engineered oral mucosa equivalents

Many conditions, including cancer, trauma, and congenital anomalies, can damage the oral mucosa. Multiple cultures of oral mucosal cells have been used for biocompatibility tests and oral biology studies. In recent decades, the clinical translation of tissue-engineered products has progressed significantly in developing tangible therapies and inspiring advancements in medical science. However, the reconstruction of an intraoral mucosa defect remains a significant challenge. Despite the drawbacks of donor-site morbidity and limited tissue supply, the use of autologous oral mucosa remains the gold standard for oral mucosa reconstruction and repair. Tissue engineering offers a promising solution for repairing and reconstructing oral mucosa tissues. Cell- and scaffold-based tissue engineering approaches have been employed to treat various soft tissue defects, suggesting the potential clinical use of tissue-engineered oral mucosa (TEOMs). In this review, we first cover the recent trends in the reconstruction and regeneration of extra-/intra-oral wounds using TEOMs. Next, we describe the current status and challenges of TEOMs. Finally, future strategic approaches and potential technologies to support the advancement of TEOMs for clinical use are discussed.

Occlusive membranes for guided regeneration of inflamed tissue defects

Guided bone regeneration aided by the application of occlusive membranes is a promising therapy for diverse inflammatory periodontal diseases. Symbiosis, homeostasis between the host microbiome and cells, occurs in the oral environment under normal, but not pathologic, conditions. Here, we develop a symbiotically integrating occlusive membrane by mimicking the tooth enamel growth or multiple nucleation biomineralization processes. We perform human saliva and in vivo canine experiments to confirm that the symbiotically integrating occlusive membrane induces a symbiotic healing environment. Moreover, we show that the membrane exhibits tractability and enzymatic stability, maintaining the healing space during the entire guided bone regeneration therapy period. We apply the symbiotically integrating occlusive membrane to treat inflammatory-challenged cases in vivo, namely, the open and closed healing of canine premolars with severe periodontitis. We find that the membrane promotes symbiosis, prevents negative inflammatory responses, and improves cellular integration. Finally, we show that guided bone regeneration therapy with the symbiotically integrating occlusive membrane achieves fast healing of gingival soft tissue and alveolar bone.

Combination therapy using multifunctional dissolvable hyaluronic acid microneedles for oral ulcers

Oral ulcers are common in the oral mucosa. Frequent occurrences of oral ulcers commonly afflict patients, seriously impacting their daily life. Treatments with good anti-inflammatory and antibacterial properties are important for promoting the healing of oral ulcers. In this study, a multifunctional, soluble hyaluronic acid (HA) microneedle (MN) patch was prepared to promote oral ulcer healing. The tip layer of the MN patch was loaded with triamcinolone acetonide (TA) and epidermal growth factor (EGF) to inhibit inflammation and promote angiogenesis. Zeolitic imidazolate framework-8 (ZIF-8) was loaded onto the base layer of the MN patch, which effectively released Zn2+ to mediate antibacterial effects. In addition, HA exerts a protective effect on the mucous membrane. Owing to these properties, the multifunctional MN patches were found to have good anti-inflammatory, antibacterial, and tissue-healing abilities, indicating that the multifunctional MN patch design successfully promoted the healing of oral ulcers.

Evaluation of the healing potential of Nile tilapia skin collagen in traumatic oral ulcers in male rats

OBJECTIVE

To evaluate the healing potential of Nile tilapia skin collagen using a rat model with experimentally induced traumatic oral ulcers.

DESIGN

Male Wistar rats were segregated into three experimental groups (n = 8/group/euthanasia day). Ulcers were induced using a dermatological punch on the left buccal mucosa. The rats were then euthanized on days 1, 5, 10, 15, and 20 (ntotal=120 rats). Each group received topical treatment, 2x/day, with 1 % Nile tilapia skin collagen orabase (experimental group), only orabase (negative control), or Oncilom-A® orabase (positive control). Ulcer area, closure percentage, and body mass variation were measured. Slides were prepared for histological analysis, which included Picrosirius red staining (collagen analysis), and immunohistochemistry (platelet endothelial cell adhesion molecule, alpha-smooth muscle actin, and transforming growth factor-beta).

RESULTS

On day 15, the experimental and positive control groups displayed smaller ulcer areas, a higher percentage of closure, complete re-epithelialization, superior histological repair scores, and a reduced count of polymorphonuclear cells in comparison to the negative control group (p < 0.05). Additionally, the experimental group exhibited an increased number of blood vessels, total collagen (types I and III) and expression of platelet endothelial cell adhesion molecule, alpha-smooth muscle actin, and transforming growth factor-beta relative to the negative and positive control groups (p < 0.05). By day 20, the experimental group showed a more significant weight gain compared to the other groups (p < 0.0001).

CONCLUSIONS

Nile tilapia skin collagen orabase optimizes the healing of traumatic ulcers by stimulating re-epithelialization, angiogenesis, and collagenesis. Transforming growth factor-beta plays a significant role in this process.

Current insights in the preclinical study of palatal wound healing and oronasal fistula after cleft palate repair

Poor palatal wound healing after cleft palate repair could lead to unfavorable prognosis such as oronasal fistula (ONF), which might affect the patient's velopharyngeal function as well as their quality of life. Thus, restoring poor palatal wound healing for avoiding the occurrence of ONF should be considered the key to postoperative care after cleft palate repair. This review provided current insights in the preclinical study of poor palatal wound healing after cleft palate repair. This review comprehensively introduced the animal model establishment for palatal wound healing and related ONF, including the models by mice, rats, piglets, and dogs, and then demonstrated the aspects for investigating poor palatal wound healing and related treatments, including possible signaling pathways that could be involved in the formation of poor palatal wound healing, the related microbiota changes because of the deformity of palatal structure, and the studies for potential therapeutic strategies for palatal wound healing and ONF. The purpose of this review was to show the state of the art in preclinical studies about palatal wound healing after cleft palate repair and to show the promising aspects for better management of palatal wound healing.

Egg white-derived peptide KPHAEVVLR promotes wound healing in rat palatal mucosa via PI3K/AKT/mTOR pathway

KPHAEVVLR (KR-9) is a peptide derived from egg white hydrolyzed, which has been found to accelerate skin wound healing in mice. However, the effect of KR-9 on wound healing on palatal mucosa in rats remains unknown, and the mechanism through which KR-9 promotes wound healing should be further explored. Herein, we aimed to investigate the effect and mechanism of KR-9 peptide on palatal mucosa wound healing. Our results showed that KR-9 reduced the wound area of palatal mucosa in rats and promoted human gingival fibroblasts(HGFs) migration and proliferation.The peptide can enter into cytoplasm. It also increased the phosphorylation of PI3K, AKT, and mTOR protein. The effect of KR-9 on HGFs migration and proliferation could be reversed by PI3K inhibitor. These results demonstrated that KR-9 peptide facilitated wound healing of palatal mucosa in rats by promoting HGFs migration and proliferation, which was mediated by PI3K/AKT/mTOR signaling pathway. This data proves that KR-9 might be used as a potential agent for wound healing treatment.

In situ photo-crosslinked hydrogel promotes oral mucosal wound healing through sustained delivery of ginsenoside Rg1

Oral mucosal wounds exhibit an increased susceptibility to inflammation as a consequence of their direct exposure to a diverse range of microorganisms. This causes pain, slow healing, and other complications that interfere with patients' daily activities like eating and speaking. Consequently, patients experience a significant decline in their overall quality of life. Therefore, the pursuit of novel treatment approaches is of great importance. In this study, ginsenoside Rg1, a natural active substance extracted from ginseng root, was chosen as a therapeutic agent. It was encapsulated in a screened photo-crosslinked hydrogel scaffold for the treatment of mucosal defects in the rat palate. The results demonstrated that Rg1-hydrogel possessed excellent physical and chemical properties, and that oral mucosa wounds treated with Rg1-hydrogel exhibited the greatest healing performance, as evidenced by more pronounced wound re-epithelialization, increased collagen deposition, and decreased inflammatory infiltration. Subsequent investigations in molecular biology confirmed that Rg1-hydrogel stimulated the secretion of repair-related factors and inhibited the secretion of inflammatory factors. This study demonstrated that the hydrogel containing ginsenoside Rg1 significantly promotes oral mucosal tissue healing in vivo. Based on the findings, it can be inferred that the Rg1-hydrogel has promising prospects for the therapeutic management of oral mucosal wounds.

The Three-Dimensional In Vitro Cell Culture Models in the Study of Oral Cancer Immune Microenvironment

The onset and progression of oral cancer are accompanied by a dynamic interaction with the host immune system, and the immune cells within the tumor microenvironment play a pivotal role in the development of the tumor. By exploring the cellular immunity of oral cancer, we can gain insight into the contribution of both tumor cells and immune cells to tumorigenesis. This understanding is crucial for developing effective immunotherapeutic strategies to combat oral cancer. Studies of cancer immunology present unique challenges in terms of modeling due to the extraordinary complexity of the immune system. With its multitude of cellular components, each with distinct subtypes and various activation states, the immune system interacts with cancer cells and other components of the tumor, ultimately shaping the course of the disease. Conventional two-dimensional (2D) culture methods fall short of capturing these intricate cellular interactions. Mouse models enable us to learn about tumor biology in complicated and dynamic physiological systems but have limitations as the murine immune system differs significantly from that of humans. In light of these challenges, three-dimensional (3D) culture systems offer an alternative approach to studying cancer immunology and filling the existing gaps in available models. These 3D culture models provide a means to investigate complex cellular interactions that are difficult to replicate in 2D cultures. The direct study of the interaction between immune cells and cancer cells of human origin offers a more relevant and representative platform compared to mouse models, enabling advancements in our understanding of cancer immunology. This review explores commonly used 3D culture models and highlights their significant contributions to expanding our knowledge of cancer immunology. By harnessing the power of 3D culture systems, we can unlock new insights that pave the way for improved strategies in the battle against oral cancer.

Functional drug-delivery hydrogels for oral and maxillofacial wound healing

The repair process for oral and maxillofacial injuries involves hemostasis, inflammation, proliferation, and remodeling. Injury repair involves a variety of cells, including platelets, immune cells, fibroblasts, and various cytokines. Rapid and adequate healing of oral and maxillofacial trauma is a major concern to patients. Functional drug-delivery hydrogels play an active role in promoting wound healing and have shown unique advantages in wound dressings. Functional hydrogels promote wound healing through their adhesive, anti-inflammatory, antioxidant, antibacterial, hemostatic, angiogenic, and re-epithelialization-promoting properties, effectively sealing wounds and reducing inflammation. In addition, functional hydrogels can respond to changes in temperature, light, magnetic fields, pH, and reactive oxygen species to release drugs, enabling precise treatment. Furthermore, hydrogels can deliver various cargos that promote healing, including nucleic acids, cytokines, small-molecule drugs, stem cells, exosomes, and nanomaterials. Therefore, functional drug-delivery hydrogels have a positive impact on the healing of oral and maxillofacial injuries. This review describes the oral mucosal structure and healing process and summarizes the currently available responsive hydrogels used to promote wound healing.

The Potential Value of Probiotics after Dental Implant Placement

Dental implantation is currently the optimal solution for tooth loss. However, the health and stability of dental implants have emerged as global public health concerns. Dental implant placement, healing of the surgical site, osseointegration, stability of bone tissues, and prevention of peri-implant diseases are challenges faced in achieving the long-term health and stability of implants. These have been ongoing concerns in the field of oral implantation. Probiotics, as beneficial microorganisms, play a significant role in the body by inhibiting pathogens, promoting bone tissue homeostasis, and facilitating tissue regeneration, modulating immune-inflammatory levels. This review explores the potential of probiotics in addressing post-implantation challenges. We summarize the existing research regarding the importance of probiotics in managing dental implant health and advocate for further research into their potential applications.

Novel Strategies for Orofacial Soft Tissue Regeneration

Significance: Orofacial structures are indispensable for speech and eating, and impairment disrupts whole-body health through malnutrition and poor quality of life. However, due to the unique and highly specialized cell populations, tissue architecture, and healing microenvironments, regeneration in this region is challenging and inadequately addressed to date. Recent Advances: With increasing understanding of the nuanced physiology and cellular responses of orofacial soft tissue, novel scaffolds, seeded cells, and bioactive molecules were developed in the past 5 years to specifically target orofacial soft tissue regeneration, particularly for tissues primarily found within the orofacial region such as oral mucosa, taste buds, salivary glands, and masseter muscles. Critical Issues: Due to the tightly packed and complex anatomy, orofacial soft tissue injury commonly implicates multiple tissue types, and thus functional unit reconstruction in the orofacial region is more important than single tissue regeneration. Future Directions: This article reviews the up-to-date knowledge in this highly translational topic, which provides insights into novel biologically inspired and engineered strategies for regenerating orofacial component tissues and functional units.

Multi-functional nanogel with cascade catalytic performance for treatment of diabetic oral mucosa ulcer

Introduction: Diabetic oral mucosa ulcers face challenges of hypoxia, hyperglycemia and high oxidative stress, which result in delayed healing process. Oxygen is regarded as an important substance in cell proliferation, differentiation and migration, which is beneficial to ulcer recovery. Methods: This study developed a multi-functional GOx-CAT nanogel (GCN) system for the treatment of diabetic oral mucosa ulcers. The catalytic activity, ROS scavenge and oxygen supply ability of GCN was validated. The therapeutic effect of GCN was verified in the diabetic gingival ulcer model. Results: The results showed that the nanoscale GCN was capable of significantly eliminating intracellular ROS, increasing intracellular oxygen concentration and accelerating cell migration of human gingival fibroblasts, which could promote diabetic oral gingival ulcer healing in vivo by alleviating inflammation and promoting angiogenesis. Discussion: This multifunctional GCN with ROS depletion, continuous oxygen supply and good biocompatibility, which might provide a novel therapeutic strategy for effective treatment of diabetic oral mucosa ulcers.

Effects of Platelet Lysate Gels Derived from Different Blood Sources on Oral Mucosal Wound Healing: An In Vitro Study

The rapid healing of oral ulcers is important to prevent secondary infection, especially for chronic oral ulcers. Platelet lysate (PL) is rich in growth factors for cell growth and promotes tissue regeneration. Hence, this study was performed to compare the effects of PL originating from umbilical cord blood (CB) and peripheral blood (PB) on oral mucosal wound healing. The PLs were molded into gel form in the culture insert with the addition of calcium chloride and conditioned medium for sustained release of growth factors. The CB-PL and PB-PL gels were found to degrade slowly in culture and their degradation percentages by weight were 5.28 ± 0.72% and 9.55 ± 1.82% respectively. The results from the scratch assay and Alamar blue assay showed that the CB-PL and PB-PL gels increased the proliferation (148 ± 3% and 149 ± 3%) and wound closure (94.17 ± 1.77% and 92.75 ± 1.80%) of oral mucosal fibroblasts compared to the control with no statistical differences between the two gels, respectively. Quantitative RT-PCR showed that mRNA expressions of collagen-I, collagen-III, fibronectin, and elastin genes in cells treated with CB-PL (11-, 7-, 2-, and 7-fold) and PB-PL (17-, 14-, 3-, and 7-fold) decreased compared with the control, respectively. The concentration of platelet-derived growth factor of PB-PL gel (1303.10 ± 343.96 pg/mL) showed a higher trend than CB-PL gel did (905.48 ± 69.65 pg/mL) from ELISA measurement. In summary, CB-PL gel is as effective as PB-PL gel in supporting oral mucosal wound healing, making it a potential new source of PL for regenerative treatment.

Dual-light defined in situ oral mucosal lesion therapy through a mode switchable anti-bacterial and anti-inflammatory mucoadhesive hydrogel

Oral mucosal ulcer is the most prevalent oral mucosal lesion, affecting the quality of life. Due to the moist and highly dynamic oral lining, the existing oral mucoadhesives are unable to serially address the challenges of residency, hemorrhage, bacterial infection and inflammatory reaction. Herein, a dual-light defined oral mucoadhesive (ZPTA-G/HMA) was proposed, with a methacrylate gelatin-methacrylate hyaluronic acid (GelMA-HAMA, G/HMA) double network hydrogel as a matrix, tannic acid (TA) as a high content anchor moiety provider for the moist oral mucosa, and polydopamine modified zinc oxide (ZnO@PDA, ZP) as a photocatalytic antibacterial substance. This platform had good adhesive and hemostatic properties both in vitro and in vivo. Under 520 nm green light (GL) irradiation, ZPTA-G/HMA would anchor to the wet mucosa surface by crosslinking and exert broad-spectrum antibacterial ability (even including Candida albicans) by in situ producing reactive oxygen species (ROS). Moreover, under 808 nm near-infrared (NIR) irradiation, the increased release of TA combined with the photothermal effect of ZP endowed ZPTA-G/HMA with enhanced anti-inflammatory and pro-healing performance. Collectively, ZPTA-G/HMA could be switched by light sources to achieve the dual-mode real-time adjustment of in situ anti-bacterial function and controlled anti-inflammation, combined with ideal mucosal residence, thus promising in developing personalized sequential strategies for varied oral mucosal lesions.

Morpho-Functional Effect of a New Collagen-Based Medical Device on Human Gingival Fibroblasts: An In Vitro Study

Maintaining periodontal and peri-implant soft tissues health is crucial for the long-term health of teeth and dental implants. New biomedical strategies aimed at avoiding connective tissue alterations and related diseases (e.g., periodontitis and peri-implantitis) are constantly evolving. Among these, collagen-based medical products have proven to be safe and effective. Accordingly, the aim of the present study was to evaluate the effects of Dental SKIN BioRegulation (Guna S.p.a., Milan, Italy), a new injectable medical device composed of type I collagen of porcine origin, on primary cultures of human gingival fibroblasts (hGF). To this end, hGF were cultured on collagen-coated (COL, 100 µg/2 mL) or uncoated plates (CTRL) before evaluating cell viability (24 h, 48 h, 72 h, and 7 d), wound healing properties (3 h, 6 h, 12 h, 24 h, and 48 h), and the activation of mechanotransduction markers, such as FAK, YAP, and TAZ (48 h). The results proved a significant increase in cell viability at 48 h (p < 0.05) and wound closure at 24 h (p < 0.001) of hGF grown on COL, with an increasing trend at all time-points. Furthermore, COL significantly induced the expression of FAK and YAP/TAZ (p < 0.05), thereby promoting the activation of mechanotransduction signaling pathways. Overall, these data suggest that COL, acting as a mechanical bio-scaffold, could represent a useful treatment for gingival rejuvenation and may possibly help in the resolution of oral pathologies.

Oral Wound Healing Potential of Polygoni Cuspidati Rhizoma et Radix Decoction—In Vitro Study

Polygoni Cuspidati Rhizoma et Radix (syn. rhizomes of Reynoutria japonica Houtt.) is a pharmacopoeial raw material in Europe and China. In traditional medicine, one of the applications for Reynoutria japonica rhizomes is wound healing. In a recent in vitro study, we demonstrated that ethanol and acetone extracts from this herbal drug have the potential to heal oral gum wounds. However, considering that a majority of herbal medicines have been traditionally administered as water decoctions, in the present study, a decoction of Reynoutria japonica rhizomes was prepared and detailed tests to determine its in vitro gingival wound healing activity were conducted. We used the primary human gingival fibroblasts (HGF) incubated with a decoction to determine cell viability (MTT assay), cell proliferation (the confocal laser scanning microscope—CLSM), and cell migration (wound healing assay). Moreover, the collagen type III expression was examined using immunocytochemical staining. The studied decoction was qualitatively and quantitatively characterized using the validated HPLC/DAD/ESI-HR-QTOF-MS method. The Folin–Ciocalteu assay was used to determine the total phenols and tannins content. Additionally, HPLC-RI analysis of decoction and the previously obtained ethanol and acetone extracts was used to determine the composition of saccharides. Low concentration (from 50 to 1000 µg/mL) of decoction after 24 h incubation caused a significant increase in HGF cell viability. No cytotoxic effect was observed at any tested concentration (up to 2000 µg/mL). The lowest active concentration of decoction (50 µg/mL) was selected for further experiments. It significantly stimulated human gingival fibroblasts to proliferate, migrate, and increase the synthesis of collagen III. Phytochemical analysis showed significantly fewer polyphenols in the decoction than in the ethanol and acetone extracts tested earlier. In contrast, high levels of polysaccharides were observed. In our opinion, they may have a significant effect on the oral wound healing parameters analyzed in vitro. The results obtained encourage the use of this raw material in its traditional, safe form—decoction.

Acceleration of Wound Healing through Amorphous Calcium Carbonate, Stabilized with High-Energy Polyphosphate

Amorphous calcium carbonate (ACC), precipitated in the presence of inorganic polyphosphate (polyP), has shown promise as a material for bone regeneration due to its morphogenetic and metabolic energy (ATP)-delivering properties. The latter activity of the polyP-stabilized ACC ("ACC∙PP") particles is associated with the enzymatic degradation of polyP, resulting in the transformation of ACC into crystalline polymorphs. In a novel approach, stimulated by these results, it was examined whether "ACC∙PP" also promotes the healing of skin injuries, especially chronic wounds. In in vitro experiments, "ACC∙PP" significantly stimulated the migration of endothelial cells, both in tube formation and scratch assays (by 2- to 3-fold). Support came from ex vivo experiments showing increased cell outgrowth in human skin explants. The transformation of ACC into insoluble calcite was suppressed by protein/serum being present in wound fluid. The results were confirmed in vivo in studies on normal (C57BL/6) and diabetic (db/db) mice. Topical administration of "ACC∙PP" significantly accelerated the rate of re-epithelialization, particularly in delayed healing wounds in diabetic mice (day 7: 1.5-fold; and day 13: 1.9-fold), in parallel with increased formation/maturation of granulation tissue. The results suggest that administration of "ACC∙PP" opens a new strategy to improve ATP-dependent wound healing, particularly in chronic wounds.

Application of Stichopus hermanni Nanoparticle Gel in the Healing of Traumatic Ulcers

OBJECTIVE

 The aim of this research was to investigate the use of Stichopus herrmanni nanoparticle gel on the ulcer healing process by observing blood vessels, fibroblasts, and Collagen type-I (COL-1) expression on the 4 and 7th days after trauma.

MATERIALS AND METHODS

 Gold sea cucumber (Stichopus herrmanni) powder was processed by freeze-drying method, then by high-energy milling to form nanoparticle size, and then with CMC 2% to make hydrogel. Traumatic ulcers were formed by induction using a burner. Five groups of male Wistar rats, each consisting of six tails, were divided into a negative control group that was given a placebo, the positive control group was given 0.2% hyaluronic acid, and the treatment group was given gold sea cucumbers with concentrations of 0.135, 0.27, and 0.54% (SH1-SH2-SH3). Fibroblast and blood vessels were examined with hematoxylin-eosin on day 3 and 7, while COL-1 expression was examined with immunohistochemistry on day 7. The rats' mucosa was taken on the 3rd and 7th days after the traumatic ulcer was formed.

STATISTICAL ANALYSIS

 The data were analyzed using a one-way analysis of variance followed by a post-hoc test with a p less than 0.05.

RESULTS

 Nanoparticles gel freeze-drying of Stichopus herrmanni increased blood vessels on day 3. Angiogenesis continued to occur, which resulted in increased fibroblast and COL-1 expression on day 7.

CONCLUSIONS

 The application of Stichopus herrmanni nanoparticle gel at 0.27% effectively increased the number of blood vessels, fibroblasts, and COL-1 expression in healing traumatic ulcers.

Acceleration of Oral Wound Healing under Diabetes Mellitus Conditions Using Bioadhesive Hydrogel

Oral wounds under diabetic conditions display a significant delay during the healing process, mainly due to oxidative stress-induced inflammatory status and abnormal immune responses. Besides, the wet and complicated dynamic environment of the oral cavity impedes stable treatment of oral wounds. To overcome these, a biomimetic hydrogel adhesive was innovatively developed based on a mussel-inspired multifunctional structure. The adhesive displays efficient adhesion and mechanical harmony on the oral mucosa through enhanced bonding in an acidic proinflammatory environment. The bioadhesive hydrogel exhibits excellent antioxidative properties by mimicking antioxidative enzymatic activities to reverse reactive oxygen species (ROS)-mediated immune disorders. Experiments on oral wounds of diabetic rats showed that this hydrogel adhesive could effectively protect against mucosal wounds and obviously shorten the inflammatory phase, thus promoting the wound-healing process. Therefore, this study offers a promising therapeutic choice with the potential to advance the clinical treatment of diabetic oral wounds.

Attached Oral Mucosal Wound Closure using Blue Glue - A Prospective Clinical Study

Introduction

Traditionally, sutures have been widely used to close intraoral wounds. Various alternatives have been developed amongst which newer tissue adhesives such as N-butyl-2-cyanoacrylate having accepted clinical properties are gaining popularity. The primary purpose of the present study is to evaluate the efficacy of N-butyl-2-cyanoacrylate for intraoral attached mucosal wound closure following alveoloplasty.

Materials and Methods

In this prospective split-mouth study, 25 patients requiring alveoloplasty in either maxillary or mandibular arch bilaterally with a total of 50 sites were divided into two equal groups, namely silk suture (Group 1) and cyanoacrylate (Group 2). Each patient was evaluated on the first, third, seventh, 14th and 21st post-operative days. Parameters evaluated were time taken to close incision and to achieve haemostasis, pain, oedema, post-operative wound healing, patient discomfort and possible complications.

Results

Time taken to close incision, time taken to achieve haemostasis, post-operative pain and oedema were found to be less in Group 2. Wound healing too was found to be better in Group 2. There was one case of adhesive peel off on the first post-operative day which was managed by reapplying the tissue adhesive. The incidence of wound dehiscence and wound infection was observed more in Group 1 on the third post-operative day. Suture breakage (16%) and adhesive dislodgement (8%) were reported on the seventh post-operative day.

Discussion

The use of cyanoacrylates' inherent benefits, such as improved wound seal off in attached mucosa, quick polymerisation and bacteriostatic characteristics can be beneficial when performing minor oral surgical procedures on elderly, young and mentally challenged patients.

A Narrative Review on Means to Promote Oxygenation and Angiogenesis in Oral Wound Healing

Oral mucosa serves as the primary barrier against pathogen invasions, mechanical stresses, and physical trauma. Although it is generally composed of keratinocytes and held in place by desmosomes, it shows variation in tissue elasticity and surface keratinization at different sites of the oral cavity. Wound healing undergoes four stages of tissue change sequences, namely haemostasis, inflammation, proliferation, and remodelling. The wound healing of oral hard tissue and soft tissue is largely dependent on the inflammatory response and vascular response, which are the targets of many research. Because of a less-robust inflammatory response, favourable saliva properties, a unique oral environment, and the presence of mesenchymal stem cells, oral wounds are reported to demonstrate rapid healing, less scar formation, and fewer inflammatory reactions. However, delayed oral wound healing is a major concern in certain populations with autoimmune disorders or underlying medical issues, or those subjected to surgically inflicted injuries. Various means of approach have been adopted to improve wound tissue proliferation without causing excessive scarring. This narrative review reappraises the current literature on the use of light, sound, mechanical, biological, and chemical means to enhance oxygen delivery to wounds. The current literature includes the use of hyperbaric oxygen and topical oxygen therapy, ultrasounds, lasers, platelet-rich plasma (PRP)/platelet-rich fibrin (PRF), and various chemical agents such as hyaluronic acid, astaxanthin, and Centella asiatica to promote angiogenesis in oral wound healing during the proliferation process. The arrival of a proprietary oral gel that is reported to improve oxygenation is highlighted.

Efficacy of low-level laser therapy in oral mucosal surgical wound healing: a systematic review and meta-analysis

Aim: Wound healing is a complex phenomenon with various biological changes in tissue integrity, low-level laser therapy (LLLT) has acquired several unique components to help into accelerating tissue reconstruction and eventually wound healing. Thus, in the present systematic review and meta-analysis study, the role of LLLT in oral mucosal wound healing following surgical interventions was investigated. Methods: The study databases, including PubMed, Web of Knowledge, Google Scholar, Scopus, and Cochrane, were searched by two blinded investigators considering eligible studies based on the following keywords: “Wound Healing”, “Oral Mucosal Wound Healing”, “Laser therapy”, “Low-level laser therapy”, “Oral Surgery”, “Photobiomodulation therapy”, among 88 screened, only 12 articles were eligible for the final analysis. Results: There was a significant difference between control and laser group in all mentioned studies in the case of wound epithelialization in gingiva, with weighted mean difference (MD) of –0.28, [95% confidence interval (CI): –0.37, –0.19, P < 0.001], periodontium 1 day postoperative, with weighted MD of –0.56 (95% CI: –0.84, –0.27, P < 0.001) and 7 days postoperative, with weighted MD of –0.73 (95% CI: –0.97, –0.49, P < 0.001). In the cases of postoperative pain, LLLT has significantly declined pain in comparison with control group with weighted MD of –0.47 (95% CI: –0.69, –0.24, P < 0.001) for 7 days postoperative and –0.55 (95% CI: –0.96, –0.13, P = 0.005) 14 days postoperatively. Conclusions: LLLT can be used as a promising tool in oral surgeries because of its inevitable capability in accelerating wound healing and reducing intraoperative pain.