Porphyromonas gingivalis impairs glucose uptake in skeletal muscle associated with altering gut microbiota.

Skeletal muscles have a high metabolic capacity, which play key roles in glucose metabolism. Although periodontal disease increases the risk of metabolic syndrome, the relationship between periodontal bacterial infection and skeletal muscle metabolic dysfunction is unclear. We found that anti-Porphyromonas gingivalis (Pg) antibody titers positively correlated with intramuscular adipose tissue content (IMAC), fasting blood glucose, and HOMA-IR in metabolic syndrome patients. In C57BL/6J mice fed a high-fat diet, recipients of oral Pg (HFPg) had impaired glucose tolerance, insulin resistance, and higher IMAC compared to recipients of saline (HFco). The soleus muscle in HFPg mice exhibited fat infiltration and lower glucose uptake with higher Tnfa expression and lower insulin signaling than in HFco mice. Gene set enrichment analysis showed that TNFα signaling via NFκB gene set was enriched in the soleus muscle of HFPg mice. Moreover, TNF-α also decreased glucose uptake in C2C12 myoblast cells in vitro. Based on 16S rRNA sequencing, Pg administration altered the gut microbiome, particularly by decreasing the abundance of genus Turicibacter. Microbial network of the gut microbiome was dramatically changed by Pg administration. Our findings suggest that infection with Pg is a risk factor for metabolic syndrome and skeletal muscle metabolic dysfunction via gut microbiome alteration.

High-frequency pulsed diode laser irradiation inhibits bone resorption in mice with ligature-induced periodontitis.

AIM: The purpose of this study was to elucidate the suppressive effect of high-frequency pulsed diode laser irradiation on bone resorption and its biological effects on gene expression and microbiome composition on the gingival tissue in ligature-induced periodontitis in mice. MATERIALS AND METHODS: Ligating ligature around the teeth and/or laser irradiation was performed on the gingival tissue in mice as follows: Co (no ligature and no laser irradiation), Li (ligation without laser irradiation), La (no ligature but with laser irradiation), and LiLa (ligation with laser irradiation). Bone resorption was evaluated using micro-computed tomography. RNA-seq analysis was performed on gingival tissues of all four groups at 3 days after ligation. The differences in microbial composition between Li and LiLa were evaluated based on the number of 16S rRNA gene sequences. RESULTS: Bone resorption caused by ligation was significantly suppressed by laser irradiation. RNA-seq in Co and La gingival tissue revealed many differentially expressed genes, suggesting diode laser irradiation altered gene expression. Gene set enrichment analysis revealed mTORC1 signalling and E2F target gene sets were enriched in gingival tissues both in La and LiLa compared with that in Co and Li, respectively. The amount of extracted DNA from ligatures was reduced by laser irradiation, and bacterial network structure was altered between the Li and LiLa. CONCLUSIONS: High-frequency pulsed diode laser irradiation showed biological effects and suppressed bone resorption in ligature-induced periodontitis.

Residual periodontal pocket treatment with Er:YAG laser-assisted comprehensive periodontal pocket therapy: a retrospective study.

OBJECTIVES: Recently, the application of erbium-doped yttrium aluminum garnet (Er:YAG) laser has been increasing in periodontal therapy. In this retrospective study, we evaluated the safety and effectiveness of a novel pocket therapy using Er:YAG laser in combination with conventional mechanical scaling and root planing treatment (Er:YAG laser-assisted comprehensive periodontal pocket therapy). METHODS: Forty sites in 29 elderly patients having residual periodontal pockets of ≥ 5 mm depth were treated by curette and Er:YAG laser from 2006 to 2009. After root debridement by curette, laser irradiation was performed on the root surfaces. Then, inflamed connective tissue on the inner gingival surface and on the bone surface/within extant bone defects was thoroughly debrided by curette and laser. Furthermore, in most cases, removal of the outer epithelium and coagulation of the blood clot in the pocket entrance were additionally performed with laser. Clinical parameters were evaluated before and 3, 6, and 12 months after treatment. RESULTS: With Er:YAG laser-assisted pocket therapy, debridement of pockets was thoroughly and safely performed, and favorable clinical improvements were observed in most cases, without any adverse side effects and complications. After 1 year, probing pocket depth significantly decreased from 6.4 ± 1.4 to 3.5 ± 1.3 mm (p < 0.001, 3.0 mm reduction), and clinical attachment level significantly decreased from 7.5 ± 1.6 to 5.2 ± 1.9 mm (p < 0.001, 2.3 mm gain). CONCLUSION: The results of this study indicate that Er:YAG laser-assisted therapy is useful for the treatment of residual pockets as a minimally invasive flapless surgery. CLINICAL RELEVANCE: Er:YAG laser-assisted comprehensive pocket therapy reduces the necessity of more conventional surgical therapies.

Laser irradiation decreases sclerostin expression in bone and osteogenic cells.

Anti-sclerostin monoclonal antibody romosozumab, a treatment for osteoporosis, reduced vertebral fracture risk and clinical fracture. Laser irradiation triggers various effects, including bio-stimulation, which can induce beneficial therapeutic effects and biological responses. Originally, we performed in vivo experiments to clarify the mechanism of better bone healing in laser-ablated bone. Here, we evaluated comprehensive and sequential gene expression in Er:YAG laser-ablated, bur-drilled, and nontreated control bones, and found laser irradiation suppressed Sost (coding protein: sclerostin) expression in the bone, possibly via stimulation of mechanotransducers. Surprisingly, bio-stimulation effect of laser suppressed Sost expression in the primary osteogenic cells. Decreased sclerostin expression after laser irradiation was also validated both in vivo and in vitro. In addition, sequential microarray analysis revealed that the gene expression pattern was clearly different at 24 hours after bone ablation between bur-drilled and laser-ablated bones. The Hippo signaling pathway was significantly enriched, whereas inflammation-related pathways were not affected at 6 hours after the laser ablation, indicating that laser irradiation caused mechanical stimulation. Only bur-drilled bone showed enriched inflammation-related gene sets and pathways at 24 hours, not in the laser-ablated bone. Our study suggests that laser irradiation may become a new treatment modality for osteoporosis, by inhibiting sclerostin expression without inducing inflammation.

Application of Ligature-Induced Periodontitis in Mice to Explore the Molecular Mechanism of Periodontal Disease.

Periodontitis is an inflammatory disease characterized by the destruction of the periodontium. In the last decade, a new murine model of periodontitis has been widely used to simulate alveolar bone resorption and periodontal soft tissue destruction by ligation. Typically, 3-0 to 9-0 silks are selected for ligation around the molars in mice, and significant bone loss and inflammatory infiltration are observed within a week. The ligature-maintained period can vary according to specific aims. We reviewed the findings on the interaction of systemic diseases with periodontitis, periodontal tissue destruction, the immunological and bacteriological responses, and new treatments. In these studies, the activation of osteoclasts, upregulation of pro-inflammatory factors, and excessive immune response have been considered as major factors in periodontal disruption. Multiple genes identified in periodontal tissues partly reflect the complexity of the pathogenesis of periodontitis. The effects of novel treatment methods on periodontitis have also been evaluated in a ligature-induced periodontitis model in mice. This model cannot completely represent all aspects of periodontitis in humans but is considered an effective method for the exploration of its mechanisms. Through this review, we aimed to provide evidence and enlightenment for future studies planning to use this model.

Relationship between NAFLD and Periodontal Disease from the View of Clinical and Basic Research, and Immunological Response.

Periodontal disease is an inflammatory disease caused by pathogenic oral microorganisms that leads to the destruction of alveolar bone and connective tissues around the teeth. Although many studies have shown that periodontal disease is a risk factor for systemic diseases, such as type 2 diabetes and cardiovascular diseases, the relationship between nonalcoholic fatty liver disease (NAFLD) and periodontal disease has not yet been clarified. Thus, the purpose of this review was to reveal the relationship between NAFLD and periodontal disease based on epidemiological studies, basic research, and immunology. Many cross-sectional and prospective epidemiological studies have indicated that periodontal disease is a risk factor for NAFLD. An in vivo animal model revealed that infection with periodontopathic bacteria accelerates the progression of NAFLD accompanied by enhanced steatosis. Moreover, the detection of periodontopathic bacteria in the liver may demonstrate that the bacteria have a direct impact on NAFLD. Furthermore, Porphyromonas gingivalis lipopolysaccharide induces inflammation and accumulation of intracellular lipids in hepatocytes. Th17 may be a key molecule for explaining the relationship between periodontal disease and NAFLD. In this review, we attempted to establish that oral health is essential for systemic health, especially in patients with NAFLD.

Combined effect of canagliflozin and exercise training on high-fat diet-fed mice.

Sodium-glucose cotransporter 2 inhibitors (SGLT2is) have been reported to improve obesity, diabetes, and nonalcoholic fatty liver disease (NAFLD) in addition to exercise training, whereas the combined effects remain to be elucidated fully. We investigated the effect of the combination of the SGLT2i canagliflozin (CAN) and exercise training in high-fat diet-induced obese mice. High-fat diet-fed mice were housed in normal cages (sedentary; Sed) or wheel cages (WCR) with or without CAN (0.03% of diet) for 4 wk. The effects on obesity, glucose metabolism, and hepatic steatosis were evaluated in four groups (Control/Sed, Control/WCR, CAN/Sed, and CAN/WCR). Numerically additive improvements were found in body weight, body fat mass, blood glucose, glucose intolerance, insulin resistance, and the fatty liver of the CAN/WCR group, whereas CAN increased food intake and reduced running distance. Exercise training alone, CAN alone, or both did not change the weight of skeletal muscle, but microarray analysis showed that each resulted in a characteristic change of gene expression in gastrocnemius muscle. In particular, in the CAN/WCR group, there was acceleration of the angiogenesis pathway and suppression of the adipogenesis pathway compared with the CAN/Sed group. In conclusion, the combination of an SGLT2i and exercise training improves obesity, insulin resistance, and NAFLD in an additive manner. Changes of gene expression in skeletal muscle may contribute, at least in part, to the improvement of obesity and insulin sensitivity.

Accuracy of cone beam computed tomography in evaluation of palatal mucosa thickness.

AIM: The purpose of this study was to investigate the accuracy of the measurement of palatal mucosa thickness using cone beam computed tomography (CBCT) and to create a conversion formula to evaluate palatal mucosa thickness more accurately. We then evaluated the palatal mucosa thickness in a Japanese population using CBCT and the conversion formula. MATERIALS AND METHODS: We evaluated palatal mucosa thickness in 10 healthy subjects at 15 sites using CBCT, digital impression, and K file. Multiple regression analysis was performed to create a conversion formula to measure thickness accurately. We then obtained CBCT data from 174 patients retrospectively, applied the conversion formula, and evaluated palatal mucosa thickness. RESULTS: Sites of measurement affected measurement error. Measurement using CBCT was 0.34 ± 0.04 mm smaller than actual measurement; therefore, a conversion formula was created. Male, age ≥60 years, and probing pocket depth ≥4 mm had significant and positive associations with palatal mucosa thickness; however, no association was observed between bleeding on probing and palatal mucosa thickness. CONCLUSION: CBCT is useful for the noninvasive and accurate measurement of palatal mucosa thickness.

In Vitro Cytological Responses against Laser Photobiomodulation for Periodontal Regeneration.

Periodontal disease is a chronic inflammatory disease caused by periodontal bacteria. Recently, periodontal phototherapy, treatment using various types of lasers, has attracted attention. Photobiomodulation, the biological effect of low-power laser irradiation, has been widely studied. Although many types of lasers are applied in periodontal phototherapy, molecular biological effects of laser irradiation on cells in periodontal tissues are unclear. Here, we have summarized the molecular biological effects of diode, Nd:YAG, Er:YAG, Er,Cr:YSGG, and CO2 lasers irradiation on cells in periodontal tissues. Photobiomodulation by laser irradiation enhanced cell proliferation and calcification in osteoblasts with altering gene expression. Positive effects were observed in fibroblasts on the proliferation, migration, and secretion of chemokines/cytokines. Laser irradiation suppressed gene expression related to inflammation in osteoblasts, fibroblasts, human periodontal ligament cells (hPDLCs), and endothelial cells. Furthermore, recent studies have revealed that laser irradiation affects cell differentiation in hPDLCs and stem cells. Additionally, some studies have also investigated the effects of laser irradiation on endothelial cells, cementoblasts, epithelial cells, osteoclasts, and osteocytes. The appropriate irradiation power was different for each laser apparatus and targeted cells. Thus, through this review, we tried to shed light on basic research that would ultimately lead to clinical application of periodontal phototherapy in the future.

The IL-33/ST2 axis is protective against acute inflammation during the course of periodontitis.

Periodontitis, which is induced by repeated bacterial invasion and the ensuing immune reactions that follow, is the leading cause of tooth loss. Periodontal tissue is comprised of four different components, each with potential role in pathogenesis, however, most studies on immune responses focus on gingival tissue. Here, we present a modified ligature-induced periodontitis model in male mice to analyze the pathogenesis, which captures the complexity of periodontal tissue. We find that the inflammatory response in the peri-root tissues and the expression of IL-6 and RANKL by Thy-1.2- fibroblasts/stromal cells are prominent throughout the bone destruction phase, and present already at an early stage. The initiation phase is characterized by high levels of ST2 (encoded by Il1rl1) expression in the peri-root tissue, suggesting that the IL-33/ST2 axis is involved in the pathogenesis. Both Il1rl1- and Il33-deficient mice exhibit exacerbated bone loss in the acute phase of periodontitis, along with macrophage polarization towards a classically activated phenotype and increased neutrophil infiltration, indicating a protective role of the IL-33/ST2 axis in acute inflammation. Thus, our findings highlight the hidden role of the peri-root tissue and simultaneously advance our understanding of the etiology of periodontitis via implicating the IL-33/ST2 axis.

Effects of low-level Er:YAG laser irradiation on proliferation and gene expression in primary gingival fibroblasts isolated from mouse maxilla.

We investigated the effects of low-level Er:YAG laser irradiation on proliferation and alternations in early gene expression of gingival fibroblasts. Mice primary gingival fibroblasts were irradiated with an Er:YAG laser (1.8, 3.9, and 5.8 J/cm2 ). Irradiation at 3.9 J/cm2 promoted cell proliferation without significant changes in lactate dehydrogenase or Hspa1a expression. Three hours after irradiation at 3.9 J/cm2 , the Fn1 expression level was significantly increased. RNA-seq identified 15 differentially expressed genes between irradiated and non-irradiated cells, some of which belonged to immediate early genes (IEGs). Kyoto Encyclopedia of Genes and Genomes pathway analysis indicated MAPK pathway enhancement, and gene set enrichment analysis showed enrichment in the TGF-ß signaling gene set. Enhanced proliferation via laser irradiation disappeared upon inhibition of Dusp4, Dusp5, and Tgfr1 expression. Low-level Er:YAG laser irradiation, especially at 3.9 J/cm2 without a major temperature elevation, enhanced fibroblast proliferation, via TGF-ß and the MAPK signaling pathway following IEG expression.

Current status of Er:YAG laser in periodontal surgery.

Lasers have numerous advantageous tissue interactions such as ablation or vaporization, hemostasis, bacterial killing, as well as biological effects, which induce various beneficial therapeutic effects and biological responses in the tissues. Thus, lasers are considered an effective and suitable device for treating a variety of inflammatory and infectious conditions of periodontal disease. Among various laser systems, the Er:YAG laser, which can be effectively and safely used in both soft and hard tissues with minimal thermal side effects, has been attracting much attention in periodontal therapy. This laser can effectively and precisely debride the diseased root surface including calculus removal, ablate diseased connective tissues within the bone defects, and stimulate the irradiated surrounding periodontal tissues during surgery, resulting in favorable wound healing as well as regeneration of periodontal tissues. The safe and effective performance of Er:YAG laser-assisted periodontal surgery has been reported with comparable and occasionally superior clinical outcomes compared to conventional surgery. This article explains the characteristics of the Er:YAG laser and introduces its applications in periodontal surgery including conventional flap surgery, regenerative surgery, and flapless surgery, based on scientific evidence from currently available basic and clinical studies as well as cases reports.

Peri-implantitis management by resective surgery combined with implantoplasty and Er:YAG laser irradiation, accompanied by free gingival graft: a case report.

The optimal method for decontamination of implant surfaces for peri-implantitis treatment remains controversial. In recent years, erbium-doped yttrium aluminum garnet (Er:YAG) laser irradiation and implantoplasty (IP) (i.e. mechanical modification of the implant) have been reported to be effective in decontaminating implant surfaces during the surgical treatment. Also, a lack of adequate keratinized mucosa (KM) around the implant is known to be associated with more plaque accumulation, tissue inflammation, attachment loss, and mucosal recession, increasing the risk of peri-implantitis. Therefore, free gingival graft (FGG) has been recommended for gaining adequate KM around the implant. However, the necessity of acquiring KM for the treatment of peri-implantitis using FGG remains unclear. In this report, we applied the apically positioned flap (APF) as resective surgery for peri-implantitis treatment in conjunction with IP and Er:YAG laser irradiation to polish/clean the implant surface. Furthermore, FGG was conducted simultaneously to create additional KM, which increased the tissue stability and contributed to the positive results. The two patients were 64 and 63 years old with a history of periodontitis. The removal of granulation tissue and debridement of contaminated implant surfaces were performed with Er:YAG laser irradiation post flap elevation and then modified smooth surfaces mechanically using IP. Er:YAG laser irradiation was also utilized to remove the titanium particles. In addition, we performed FGG to increase the width of KM as a vestibuloplasty. Peri-implant tissue inflammation and progressive bone resorption were not observed, and both patients maintained good oral hygiene conditions until the 1-year follow-up appointment. Bacterial analysis via high-throughput sequencing revealed proportional decreases in bacteria associated with periodontitis (Porphyromonas, Treponema, and Fusobacterium). To the best of our knowledge, this study is the first to describe peri-implantitis management and bacterial change before and after procedures by resective surgery combined with IP and Er:YAG laser irradiation for peri-implantitis treatment, accompanied by FGG for increasing KM around the implants.

Blue Light-Emitting Diode Irradiation Without a Photosensitizer Alters Oral Microbiome Composition of Ligature-Induced Periodontitis in Mice.

Objective: This study investigated the suppressive effects of blue light-emitting diode (LED) irradiation on bone resorption and changes in the oral microbiome of mice with ligature-induced periodontitis. Background: Wavelength of blue light has antimicrobial effects; however, whether blue LED irradiation alone inhibits the progression of periodontitis remains unclear. Methods: Nine-week-old male mice ligated ligature around the right maxillary second molar was divided into ligation alone (Li) and ligation with blue LED irradiation (LiBL) groups. The LiBL group underwent blue LED (wavelength, 455 nm) irradiation four times in a week at 150 mW/cm2 without a photosensitizer on the gingival tissue around the ligated tooth at a distance of 5 mm for 5 min. The total energy density per day was 45 J/cm2. Bone resorption was evaluated using micro-computed tomography at 8 days. Differences in the oral microbiome composition of the collected ligatures between the Li and LiBL groups were analyzed using next-generation sequencing based on the 16S rRNA gene from the ligatures. Results: Blue LED irradiation did not suppress bone resorption caused by ligature-induced periodontitis. However, in the LiBL group, the α-diversity, number of observed features, and Chao1 were significantly decreased. The relative abundances in phylum Myxococcota and Bacteroidota were underrepresented, and the genera Staphylococcus, Lactococcus, and Lactobacillus were significantly overrepresented by blue LED exposure. Metagenomic function prediction indicated an increase in the downregulated pathways related to microbial energy metabolism after irradiation. The co-occurrence network was altered to a simpler structure in the LiBL group, and the number of core genera decreased. Conclusions: Blue LED irradiation altered the composition and network of the oral microbiome of ligature-induced periodontitis in mice.

Homemade blenderized tube feeding improves gut microbiome communities in children with enteral nutrition.

Enteral nutrition for children is supplied through nasogastric or gastrostomy tubes. Diet not only influences nutritional intake but also interacts with the composition and function of the gut microbiota. Homemade blenderized tube feeding has been administered to children receiving enteral nutrition, in addition to ready-made tube feeding. The purpose of this study was to evaluate the oral/gut microbial communities in children receiving enteral nutrition with or without homemade blenderized tube feeding. Among a total of 30 children, 6 receiving mainly ready-made tube feeding (RTF) and 5 receiving mainly homemade blenderized tube feeding (HBTF) were analyzed in this study. Oral and gut microbiota community profiles were evaluated through 16S rRNA sequencing of saliva and fecal samples. The α-diversity representing the number of observed features, Shannon index, and Chao1 in the gut were significantly increased in HBTF only in the gut microbiome but not in the oral microbiome. In addition, the relative abundances of the phylum Proteobacteria, class Gammaproteobacteria, and genus Escherichia-Shigella were significantly low, whereas that of the genus Ruminococcus was significantly high in the gut of children with HBTF, indicating HBTF altered the gut microbial composition and reducing health risks. Metagenome prediction showed enrichment of carbon fixation pathways in prokaryotes at oral and gut microbiomes in children receiving HBTF. In addition, more complex network structures were observed in the oral cavity and gut in the HBTF group than in the RTF group. In conclusion, HBTF not only provides satisfaction and enjoyment during meals with the family but also alters the gut microbial composition to a healthy state.

Association between periodontal disease and chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) and periodontal disease are chronic inflammatory conditions that significantly affect an individual's overall health and well-being. Generally, the prevalence of periodontitis is higher in patients with COPD than those without COPD, which may partly be attributed to common risk factors in COPD, such as smoking, respiratory infections, and inflammation. In particular, periodontitis may exacerbate the progression of COPD and further deteriorate the respiratory system by promoting inflammatory responses and bacterial infections. Immunocytes, including neutrophils, and microorganisms such as Fusobacterium nucleatum originating from oral biofilms are believed to be crucial factors influencing to COPD. Furthermore, the potential benefits of treating periodontal disease in COPD outcomes have been investigated. Although the relationship between COPD and periodontal disease has been preliminarily studied, there is currently a lack of large-scale clinical studies to validate this association. In addition to clinical examinations, investigating biomarkers and microbiology may contribute to explore the underlying mechanisms involved in the management of these conditions. This review aims to contribute to a better understanding of the clinical and basic research aspects of COPD and periodontitis, allowing for potential therapeutic approaches and interdisciplinary management strategies.

Er:YAG laser-assisted comprehensive periodontal pocket therapy for residual periodontal pocket treatment: A randomized controlled clinical trial.

BACKGROUND: This study evaluated the effectiveness of a novel pocket therapy (Er:YAG laser-assisted comprehensive periodontal pocket therapy [Er-LCPT]) for residual pocket treatment, compared with conventional mechanical treatment alone, in a randomized controlled clinical trial. METHODS: Two sites in 18 patients having residual periodontal pockets of ≥5 mm depth, extant following initial active therapy, or during supportive therapy, were randomized into two groups in a split mouth design: the control group received scaling and root planing (SRP) by curette, and the test group received Er-LCPT using curette and laser. With Er-LCPT, after root debridement, inflamed connective tissue on the inner gingival surface and on the bone surface/within extant bone defects was thoroughly debrided. Furthermore, removal of proximate oral epithelium and coagulation of the blood clot in the pocket entrance were performed with laser. Clinical parameters were evaluated, before and after treatment, through 12 months. RESULTS: Both groups showed significant improvements in clinical parameters. With Er-LCPT, pocket debridement was thoroughly and safely performed, without any adverse side effects and complications, and favorable healing was observed in most of the cases. At 12 months, Er-LCPT demonstrated significantly higher probing pocket depth reduction (2.78 mm vs. 1.89 mm on average; p = 0.012, Wilcoxon signed-rank test), clinical attachment gain (1.67 mm vs. 1.06 mm; p = 0.004) as primary outcomes, and reduced BOP value (0.89 vs. 0.56; p = 0.031), compared with SRP alone. CONCLUSION: The results of this study indicate that Er-LCPT is more effective for residual pocket treatment, compared with SRP alone.

Novel and Efficient Method for Diagnosing Infective Endocarditis Using 16S Ribosomal RNA Gene Amplicon Sequence.

We present 2 cases that both developed infective endocarditis and underwent mitral valve replacement. In addition to positive blood culture and echocardiographic findings, such as vegetation or mitral valve perforation, the 16S ribosomal RNA gene amplicon sequence approach used was helpful for disease diagnosis. (Level of Difficulty: Intermediate.).

Corrigendum: Comparison of Periodontal Bacteria of Edo and Modern Periods Using Novel Diagnostic Approach for Periodontitis With Micro-CT.

[This corrects the article DOI: 10.3389/fcimb.2021.723821.].

Comprehensive and Sequential Gene Expression Analysis of Bone Healing Process Following Er:YAG Laser Ablation.

Objective: This study evaluated the comprehensive and sequential gene expression in laser-ablated bone compared with that in nontreated control bone. Background: Bone ablation by Er:YAG laser has shown positive effects on bone healing; however, the gene expression responses that occur during bone healing remain unclear. Materials and methods: The calvarial bone of male, 10-week-old Wistar rats was ablated by Er:YAG laser. Gene expression in the laser-ablated bone and nontreated control bone was evaluated at 6, 24, and 72 h using microarray analysis. Messenger RNA (mRNA) expression levels were validated by quantitative reverse transcription-polymerase chain reaction. Results: Gene expression of BCAR1/p130Cas (breast cancer anti-estrogen resistance 1/p130 Crk-associated substrate), a mechanotransducer, was gradually increased. Additionally, upstream of the Hippo signaling pathway was enriched according to Kyoto Encyclopedia of Genes and Genomes pathway analysis at 6 h. F-actin mRNA expression was also gradually increased, whereas the Hippo signaling pathway was downregulated from 6 to 24 h. Enrichment of bone formation-related Gene Ontology (GO) terms was observed from an early stage, whereas inflammation-related GO terms, gene sets, and mRNA expression of Nfkb1, Tnf, and Il1b were gradually enriched after 24 h. Conclusions: Bone ablation by Er:YAG laser regulated the expression of Bcar1 and Actg1, the main regulators of mechanotransduction in the bone tissue. Additionally, inflammation was gradually increased up to 72 h following bone ablation with Er:YAG laser. Laser influences the expression of genes associated with bone formation immediately after irradiation. Therefore, mechanical stress and the biological effects caused by Er:YAG laser irradiation potentially contribute to wound healing in the laser-ablated bone tissue.