CXCL5/CXCL8 induces neutrophilic inflammation in peri-implantitis.

OBJECTIVE AND BACKGROUND: This research aimed to examine the role of C-X-C motif chemokine ligand 5 (CXCL5) and C-X-C motif chemokine ligand 8 (CXCL8; also known as IL-8) in neutrophilic inflammation triggered by peri-implantitis and to shed light on the underlying mechanisms that link them to the development of this condition. MATERIALS: This study included 40 patients who visited the Department of Periodontology at Kyungpook University Dental Hospital. They were divided into two groups based on their condition: healthy implant (HI) group (n = 20) and peri-implantitis (PI) group (n = 20). Biopsy samples of PI tissue were collected from the patients under local anesthesia. HI tissue was obtained using the same method during the second implant surgery. To construct libraries for control and test RNAs, the QuantSeq 3' mRNA-Seq Library Prep Kit (Lexogen, Inc., Austria) was used according to the manufacturer's instructions. Samples were pooled based on representative cytokines obtained from RNA sequencing results and subjected to Reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Hematoxylin and eosin staining, and immunohistochemistry (IHC) analysis were performed to visually assess expression levels and analyze tissue histology. Student's t-test was employed to conduct statistical analyses. RESULTS: Initially, heatmaps were used to examine gene expression variations between the HI and PI groups based on the results of RNA sequencing. Notably, among various cytokines, CXCL5 and CXCL8 had the highest expression levels in the PI group compared with the HI group, and they are known to be associated with inflammatory responses. In the gingival tissues, the expression of genes encoding cytokines such as interleukin (IL)-1ß, tumor necrosis factor-alpha (TNF)-α, interleukin (IL)-6, and CXCL5/CXCL8 was assessed via RT-qPCR. The mRNA expression level of CXCL5/CXCL8 significantly increased in the PI group compared with the HI group (p < .045). Contrarily, the mRNA expression level of interleukin 36 receptor antagonist (IL36RN) significantly decreased (p < .008). IHC enabled examination of the distribution and intensity of CXCL5/CXCL8 protein expression within the tissue samples. Specifically, increased levels of CXCL5/CXCL8 promote inflammatory responses, cellular proliferation, migration, and invasion within the peri-implant tissues. These effects are mediated through the activation of the PI3K/Akt/NF-κB signaling pathway. CONCLUSIONS: This study found that the PI sites had higher gene expression level of CXCL8/CXCL5 in the soft tissue than HI sites, which could help achieve more accurate diagnosis and treatment planning.

Longitudinal Study of Bone Height Change between Two Approaches for Sinus Floor Elevation.

Background and Objectives: The purpose of this study is to assess the long-term maintenance of each approach of sinus elevation, the crestal approach and lateral approach, by comparing the radiographic results of each technique. Materials and Methods: In total, 103 patients who had undergone an implant procedure with either the crestal approach or lateral approach method applied to their maxillary molar edentulous area were included. Using orthopantomographs, the radiographic changes were consistently evaluated over 3 years after the procedure (immediately after procedure and 1 year, 2 years and 3 years after implant placement) Results: The radiographic evaluation after 3 years of implantation with sinus elevation showed a significant amount of bone formation (8.07 mm for crestal approach and 12.00 mm for lateral approach method). The largest amount of grafted height loss occurred during the 1 year, but the resorption was minimal (0.98 mm for crestal approach and 0.95 mm for lateral approach method) over the entire 3 years. Conclusions: Although the lateral approach showed more bone growth, the amount of bone resorption was similar to that of the crestal approach. Both methods showed the highest amount of bone resorption in the first year, and the amount of change thereafter was insignificant. It is judged that both methods can be used according to the situation to help implant placement.

Long-Term Survival Rate of Autogenous Tooth Transplantation: Up to 162 Months.

Background and Objectives: The purpose of this study is to observe the usefulness of autogenous tooth transplantation by examining the cumulative survival rate according to the period of auto-transplanted teeth as pre-implant treatment. Materials and Methods: This study was conducted on 111 patients who visited Kyungpook National University Dental Hospital and underwent autogenous tooth transplantation between November 2008 and January 2021 (about 13 years). The cumulative survival rate of autogenous tooth transplantation according to the causes of extraction of the recipient tooth (caries, periapical lesion, crack, crown fracture, periodontitis) and condition of opposing teeth (natural teeth vs. fixed prosthesis). The cumulative survival rate of autogenous tooth transplantation according to the age (under 30 vs. over 30) was also investigated and it was examined whether there were any differences in each factor. Results: The average follow-up period was 12 months, followed by a maximum of 162 months. The 24-month cumulative survival rate of all auto-transplanted teeth was 91.7%, 83.1% at 60 months and the 162-month cumulative survival rate was 30.1%. There were no statistical differences between the causes of extraction of the recipient's teeth, differences in the condition of the opposing teeth, and differences under and over the age of 30. Conclusions: The survival rate of autogenous tooth transplantation appears to be influenced by the conditions of the donor tooth rather than the conditions of the recipient tooth. Although autogenous tooth transplantation cannot completely replace implant treatment, it is meaningful in that it can slightly delay or at least earn the time until implant placement is possible.

IL-17 promotes osteoblast differentiation, bone regeneration, and remodeling in mice.

Bone homeostasis is maintained by concerted actions of bone-forming osteoblasts and bone-resorbing osteoclasts. A wide range of evidence indicates that a proinflammatory cytokine IL-17 promotes osteoclastogenesis. However, the role of IL-17 in osteoblasts is less well-understood. In the current study, the effect of IL-17 on osteogenic differentiation was investigated in mouse calvarial cells. IL-17 stimulated osteoblast differentiation, mineralization, proliferation, motility, and osteoblast-dependent osteoclastogenesis in vitro. The pro-osteogenic role of IL-17 was dependent on Act1 and the generation of reactive oxygen species. In a critical size calvarial defect model, IL-17 significantly augmented bone regeneration. Importantly, IL-17 also remarkably increased bone remodeling and restored osteoclastogenesis in zoledronate-treated mice. Furthermore, IL-17 conspicuously stimulated the formation of lamellar bones. These data not only provide a clue to understand the role of IL-17 in bone metabolism but also suggest possible applications in bone augmentation therapies.

Visualization of woven bone structure through analysis of biopsy specimens using synchrotron radiation and conventional X-ray microcomputed tomography.

This study explores the application of synchrotron radiation and conventional microcomputed tomography (SR-µCT and C-µCT, respectively) in evaluating bone-biopsy specimens. Bone-biopsy specimens were obtained using a trephine bur during bone-graft removal for implant placement six months after performing a maxillary sinus bone-graft procedure. Image data of specimens were obtained using SR-µCT and C-µCT. SR-µCT was performed using the 6C biomedical imaging beamline at the Pohang Accelerator Laboratory with a monochromatic X-ray beam of 23 keV, and C-µCT was performed using a table-top CT scanner (Skyscan 1272). Reconstruction images obtained using the two methods were qualitatively compared with 2D images evaluated under 3D visualization. The SR-µCT images, especially of the new-bone-graft-woven-bone formation, were less noisy and sharper than the C-µCT images. To evaluate the new-bone-graft-woven-bone formation, only the SR-µCT images showed areas of new bone (NB) formation with bone substitute (BS; Bio-Oss) and woven bone (WB) contact, and correctly visualized true 3D structures of bone formation. Hence, µCT techniques are non-destructive and can provide detailed images of bone biopsy. In particular, SR-µCT can be used to obtain improved image quality with contrast of NB, BS and WB, demonstrating a level of detail comparable with bone formation. SR-µCT could be an unbiased 3D alternative for imaging WB formation and for high-throughput analysis.

Effects of resveratrol on bone-healing capacity in the mouse tooth extraction socket.

BACKGROUND AND OBJECTIVE: After tooth extraction, the extraction socket undergoes several steps of soft and hard tissue healing. The healing process of the extraction socket is modulated by a range of signaling factors and biochemical agents. It has been reported that resveratrol, a polyphenolic compound, exhibits various biological effects, including anti-inflammatory, anti-carcinogenic, antioxidant, and anti-aging effects, and protects cardiovascular and bone tissues. In this study, we examined the cellular effects of resveratrol on human periodontal ligament (hPDL) cells and osteoblast-like (MC3T3-E1) cells and evaluated the bone-healing capacity of tooth extraction sockets in mice. MATERIAL AND METHODS: Resveratrol was applied to hPDL and MC3T3-E1 cells to detect cell proliferation and alkaline phosphatase (ALP) activity, and qPCR was employed to understand the gene expression level in vitro. For in vivo experiment, six-week-old C57BL/6 male mice were randomly divided into control (n = 15) and experimental (n = 15) groups and maxillary first molars were extracted by surgery. Experimental groups received 50-µM resveratrol on extraction sockets and analyzed the degree of new bone formation. RESULTS: Treatment of hPDL and MC3T3-E1 cells with resveratrol increased the cell proliferation and ALP activity and enhanced the expression of ALP, BMP-2, BMP-4, and OC genes. Resveratrol enhanced new bone formation in the lingual extraction socket in mice. CONCLUSION: These results suggest that resveratrol increases the cellular physiology of PDL and osteoblast including their proliferation and differentiation and may play an important role in bone-healing capacity after tooth extraction.

High-Throughput Analysis of New Bone Formation and Bone Substitutes After Maxillary Sinus Floor Elevation Using Synchrotron Radiation Micro-Computed Tomography.

This study addresses the usability of synchrotron radiation micro-computed tomography (SR-µCT) for the high-throughput examination of bone biopsy specimens harvested from maxillary sinus floor elevation (MSFE) patients. The experimental procedure devised for efficient data acquisition and volume analysis of bone biopsy specimens of sinus lift using SR-µCT is presented. The measuring was done in approximately one minute per field of view; 3D image visualization and volume analysis could be performed in one hour. Six months after the sinus floor augmentation procedure, bone biopsy specimens were collected. Six specimens were studied. The percentages of bone measured by 3D volumetric analysis using SR-µCT and 2D area analysis using conventional histomorphometry were compared. A specimen was measured in any cross section, and the analysis was readily extended to the entire volume of the specimen. Significant differences between the 2D and the 3D measurement results were revealed. Based on our observations, we report structural inhomogeneity in the grafted volume of the MSFE site. The new bone volume assessed by SR-µCT correlates with the percentage of bone as assessed by conventional 2D histologic photomicrographs. SR-µCT is thus a reliable technique to determine the volume of newly formed bone at the MSFE.

Comparative Evaluation of Recombinant Human Bone Morphogenetic Protein-2/Hydroxyapatite and Bovine Bone for New Bone Formation in Alveolar Ridge Preservation.

PURPOSE: Hydroxyapatite treated with recombinant human bone morphogenetic protein-2/Hydroxyapatite (rhBMP-2/HA) or bovine bone was applied on extraction sockets for alveolar ridge preservation, and the results were compared with respect to clinical and histological bone formation. MATERIALS AND METHODS: This was a prospective, randomized controlled clinical trial performed on 20 implant placement sites (10 in the experimental and 10 in the control group). rhBMP-2/HA was applied on extraction sockets in the experimental group and bovine bone on those of the control group. The bone at the corresponding sites was biopsied 3 months later, and clinical, histological, and histomorphometric analyses were performed. RESULTS: The alveolar bone height was well preserved in both groups with relatively less change in width in the experimental group compared with the control group. The percentage of new bone was 25.37% ± 17.23% in the experimental group and 6.13% ± 4.32% in the control group; the difference was statistically significant. CONCLUSIONS: The alveolar ridge was preserved clinically and histologically in both groups. rhBMP-2/HA resulted in greater new bone formation than bovine bone 3 months after the surgery.

Effects of Enhanced Hydrophilic Titanium Dioxide-Coated Hydroxyapatite on Bone Regeneration in Rabbit Calvarial Defects.

The regeneration of bone defects caused by periodontal disease or trauma is an important goal. Porous hydroxyapatite (HA) is an osteoconductive graft material. However, the hydrophobic properties of HA can be a disadvantage in the initial healing process. HA can be coated with TiO2 to improve its hydrophilicity, and ultraviolet irradiation (UV) can further increase the hydrophilicity by photofunctionalization. This study was designed to evaluate the effect of 5% TiO2-coated HA on rabbit calvarial defects and compare it with that of photofunctionalization on new bone in the early stage. The following four study groups were established, negative control, HA, TiO2-coated HA, and TiO2-coated HA with UV. The animals were sacrificed and the defects were assessed by radiography as well as histologic and histomorphometric analyses. At 2 and 8 weeks postoperatively, the TiO2-coated HA with UV group and TiO2-coated HA group showed significantly higher percentages of new bone than the control group (p < 0.05). UV irradiation increased the extent of new bone formation, and there was a significant difference between the TiO2-coated HA group and TiO2-coated HA with UV group. The combination of TiO2/HA and UV irradiation in bone regeneration appears to induce a favorable response.

Transcriptome sequencing of gingival biopsies from chronic periodontitis patients reveals novel gene expression and splicing patterns.

BACKGROUND: Periodontitis is the most common chronic inflammatory disease caused by complex interaction between the microbial biofilm and host immune responses. In the present study, high-throughput RNA sequencing was utilized to systemically and precisely identify gene expression profiles and alternative splicing. METHODS: The pooled RNAs of 10 gingival tissues from both healthy and periodontitis patients were analyzed by deep sequencing followed by computational annotation and quantification of mRNA structures. RESULTS: The differential expression analysis designated 400 up-regulated genes in periodontitis tissues especially in the pathways of defense/immunity protein, receptor, protease, and signaling molecules. The top 10 most up-regulated genes were CSF3, MAFA, CR2, GLDC, SAA1, LBP, MME, MMP3, MME-AS1, and SAA4. The 62 down-regulated genes in periodontitis were mainly cytoskeletal and structural proteins. The top 10 most down-regulated genes were SERPINA12, MT4, H19, KRT2, DSC1, PSORS1C2, KRT27, LCE3C, AQ5, and LCE6A. The differential alternative splicing analysis revealed unique transcription variants in periodontitis tissues. The EDB exon was predominantly included in FN1, while exon 2 was mostly skipped in BCL2A1. CONCLUSIONS: These findings using RNA sequencing provide novel insights into the pathogenesis mechanism of periodontitis in terms of gene expression and alternative splicing.

Analysis of the esthetic outcome after root coverage procedures using a comprehensive approach.

STATEMENT OF THE PROBLEM: There is a reported gap between the relative satisfaction of the clinician and patient after a root coverage procedure. In addition, there may also be a disparity between objective esthetic evaluation tools and subjective satisfaction. METHODS: This study included 58 sites in 31 patients who had undergone root coverage procedures. The percentage of root coverage and the root coverage esthetic score system were used as objective measurements. A questionnaire with a five-point ordinal scale was used for subjective evaluation. Initial recession depth and width, Miller classification, tissue biotype, treatment procedures, and follow-up periods were considered as associated factors. RESULTS: After a period of at least 6 months from the procedure, the patient-perceived outcome showed a better match with the root coverage esthetic scoring system than the percentage of root coverage alone. A lower value for objective outcome was obtained for a deeper gingival recession and higher Miller class, but the subjective outcome displayed a steady trend. All four esthetic results were at their lowest after an epithelialized free soft tissue graft. CONCLUSION: An esthetic outcome according to patient satisfaction was not always consistent with that determined by professional scoring. In addition, partial root coverage may be viewed as a positive outcome by patients and clinicians in cases of deep gingival recession and high Miller class. CLINICAL SIGNIFICANCE: This study evaluates the esthetic outcome of root coverage procedures using an objective method, including the percentage of root coverage, root coverage esthetic scoring system, and subjective assessment by patient and clinician-based questionnaires. The results will be helpful for the understanding of the differences that exist in esthetic satisfaction.

Resveratrol facilitates bone formation in high-glucose conditions.

Periodontitis is known to be affected by high-glucose conditions, which poses a challenge to periodontal tissue regeneration, particularly in bone formation. In this study, the potential effects of resveratrol (3,5,4'-trihydroxystilbene, RSV) in facilitating bone formation under high-glucose conditions after periodontitis has been investigated. We focused on the analysis of osteoblasts and periodontal ligament cells, which are essential for bone formation including cell proliferation and differentiation. And we aimed to investigate the impact of RSV on bone healing, employed diabetic mouse model induced by streptozotocin and confirmed through histological observation. High-glucose conditions adversely affected cell proliferation and ALP activity in both MC3T3-E1 and hPDLF in vitro, with more significant impact on MC3T3-E1 cells. RSV under high-glucose conditions had positive effects on both, showing early-stage effects for MC3T3-E1 cells and later-stage effects for hPDLF cells. RSV seemed to have a more pronounced rescuing role in MC3T3-E1 cells. Increased ALP activity was observed and the expression levels of significant genes, such as Col 1, TGF-ß1, ALP, and OC, in osteogenic differentiation were exhibited stage-specific expression patterns. Upregulated Col 1 and TGF-ß1 were detected in the early stage, and then ALP and OC expressions became more pronounced in the later stages. Similarly, stronger positive reactions against RUNX2 were detected in the RSV-treated group compared to the control. Furthermore, in in vivo experiment, RSV stimulates the growth and differentiation of osteoblasts, thereby promoting bone formation. High-glucose levels have the potential to impair cellular functions and the regenerative capacity to facilitate bone formation with MC3T3-E1 rather than hPDLF cells. Resveratrol appears to facilitate the inherent abilities of MC3T3-E1 cells compared with hPDLF cells, indicating its potential capacity to restore functionality during periodontal regeneration.

PINK1 restrains periodontitis-induced bone loss by preventing osteoclast mitophagy impairment.

The oral colonization of periodontal pathogens onto gingival tissues establishes hypoxic microenvironment, often disrupting periodontal homeostasis in conjunction with oxidative stress. The association between reactive oxygen species (ROS) and osteolytic periodontitis have been suggested by recent studies. PTEN-induced kinase 1 (PINK1), a mitochondrial serine/threonine kinase, is an essential protein for mitochondrial quality control as it protects cells from oxidative stress by promoting degradation of damaged mitochondria through mitophagy. However, the pathophysiological roles of PINK1 in osteoclast-mediated bone loss have not been explored. Here we aimed to determine whether PINK1 plays a role in the regulation of osteoclastogenesis and alveolar bone resorption associated with periodontitis. C57BL/6 wild type (WT) and Pink1 knockout (KO) mice were subjected to ligature-induced periodontitis (LIP), and alveolar bones were evaluated by µCT-analysis and tartrate-resistant acid phosphatase (TRAP) staining. The µCT-analysis showed that bone volume fraction and travecular thickness were lower in Pink1 KO compared to WT mice. The number of TRAP-positive osteoclasts was markedly increased in the periodontal tissues of Pink1 KO mice with LIP. The genetic silencing or deletion of Pink1 promoted excessive osteoclast differentiation and bone resorption in vitro, as respectively indicated by TRAP staining and resorption pits on dentin slices. PINK1 deficiency led to mitochondrial instabilities as indicated by confocal microscopy of mitochondrial ROS, mitochondrial oxygen consumption rate (OCR) analysis, and transmission electron microscopy (TEM). Consequently, a significant increase in Ca2+-nuclear factor of activated T cells 1 (NFATc1) signaling was also found. On the other hand, restoration of mitophagy and autophagy by spermidine (SPD) treatment and the resolution of oxidative stress by N-acetyl-l-cysteine (NAC) treatment protected PINK1 deficiency-induced excessive generation of osteoclasts. Taken together, our findings demonstrate that PINK1 is essential for maintaining mitochondrial homeostasis during osteoclast differentiation. Therefore, targeting PINK1 may provide a novel therapeutic strategy for severe periodontitis with fulminant osteolysis.

Mer tyrosine kinase regulates bone metabolism, and its deficiency partially ameliorates periodontitis- and ovariectomy-induced bone loss in mice.

Bone homeostasis is maintained by tightly coordinated activities of bone-forming osteoblasts and bone-resorbing osteoclasts. In the present report, the role of Mer tyrosine kinase (MerTK) in bone metabolism was investigated. The expression of MerTK decreased upon BMP2 stimulation of osteoblast precursors. The femurs of Mertk-deficient mice showed significantly increased bone volume with concomitant increase of bone formation and reduction in bone resorption. These bone phenotypes were attributed to the increased osteoblast differentiation and mineralization accounted by the enhanced ß-catenin and Smad signaling in the absence of MerTK in osteoblast precursors. Although the Mertk-deficient bone marrow macrophages were predisposed to enhanced osteoclast differentiation via augmented Ca2+-NFATc1 signaling, the dramatic increase of Tnfsf11b/Tnfsf11 (Opg/Rankl) ratio in Mertk knockout bones and osteoblast precursors corroborated the reduction of osteoclastogenesis in Mertk deficiency. In ligature-induced periodontitis and ovariectomy models, the bone resorption was significantly attenuated in Mertk-deficient mice compared with wild-type control. Taken together, these data indicate novel role of MerTK in bone metabolism and suggest a potential strategy targeting MerTK in treating bone-lytic diseases including periodontitis and osteoporosis.

Imatinib inhibits oral squamous cell carcinoma by suppressing the PI3K/AKT/mTOR signaling pathway.

Oral squamous cell carcinoma (OSCC) is a prevalent oral and maxillofacial cancer with high mortality as OSCC cells readily invade tissues and metastasize to cervical lymph nodes. Although imatinib exhibits potential anticancer and remarkable clinical activities that therapeutically affect several cancer types, its specific impact on OSCC has yet to be fully explored. Therefore, this study investigated the potential anticancer effect of imatinib on OSCC cells and the underlying mechanisms. The Cell Counting Kit-8 was used to determine the impact of imatinib on cell viability. Then, morphological cell proliferation analysis was conducted to examine how imatinib impacted OSCC cell growth. Moreover, OSCC cell migration was determined through wound-healing assays, and colony formation abilities were investigated through the soft agar assay. Lastly, the effect of imatinib on OSCC cell apoptosis was verified with flow cytometry, and its inhibitory mechanism was confirmed through Western blot. Our results demonstrate that imatinib effectively inhibited OSCC cell proliferation and significantly curtailed OSCC cell viability in a time- and concentration-dependent manner. Furthermore, imatinib suppressed migration and colony formation while promoting OSCC cell apoptosis by enhancing p53, Bax, and PARP expression levels and reducing Bcl-2 expression. Imatinib also inhibited the PI3K/AKT/mTOR signaling pathway and induced OSCC cell apoptosis, demonstrating the potential of imatinib as a treatment for oral cancer.

The Impact of Mechanical Debridement Techniques on Titanium Implant Surfaces: A Comparison of Sandblasted, Acid-Etched, and Femtosecond Laser-Treated Surfaces.

This study evaluated the effects of various mechanical debridement methods on the surface roughness (Ra) of dental implants, comparing femtosecond laser-treated surfaces with conventionally machined and sandblasted with large-grit sand and acid-etched (SLA) implant surfaces. The fabrication of grade 4 titanium (Ti) disks (10 mm in diameter and 1 mm thick) and the SLA process were carried out by a dental implant manufacturer (DENTIS; Daegu, Republic of Korea). Subsequently, disk surfaces were treated with various methods: machined, SLA, and femtosecond laser. Disks of each surface-treated group were post-treated with mechanical debridement methods: Ti curettes, ultrasonic scaler, and Ti brushes. Scanning electron microscopy, Ra, and wettability were evaluated. Statistical analysis was performed using the Kruskal-Wallis H test, with post-hoc analyses conducted using the Bonferroni correction (α = 0.05). In the control group, no significant difference in Ra was observed between the machined and SLA groups. However, femtosecond laser-treated surfaces exhibited higher Ra than SLA surfaces (p < 0.05). The application of Ti curette or brushing further accentuated the roughness of the femtosecond laser-treated surfaces, whereas scaling reduced the Ra in SLA surfaces. Femtosecond laser-treated implant surfaces, with their unique roughness and compositional attributes, are promising alternatives in dental implant surface treatments.

Effect of Electrocautery and Laser Treatment on the Composition and Morphology of Surface-Modified Titanium Implants.

The purpose of this study was to investigate the effects of different peri-implantitis treatment methods (Er,Cr:YSGG laser, diode laser, and electrocautery) on various titanium implant surfaces: machined; sandblasted, large-grit, and acid-etched; and femtosecond laser-treated surfaces. Grade 4 titanium (Ti) disks, with a diameter of 10 mm and a thickness of 1 mm, were fabricated and treated using the aforementioned techniques. Subsequently, each treated group of disks underwent different peri-implantitis treatment methods: Er,Cr:YSGG laser (Biolase, Inc., Foothill Ranch, CA, USA), diode laser (Biolase, Inc., Foothill Ranch, CA, USA), and electrocautery (Ellman, Hicksville, NY, USA). Scanning electron microscopy, energy-dispersive X-ray spectroscopy, and wettability were used to characterize the chemical compositions and surfaces of the treated titanium surfaces. Significant changes in surface roughness were observed in both the electrocautery (Sa value of machined surface = 0.469, SLA surface = 1.569, femtosecond laser surface = 1.741, and p = 0.025) and Er,Cr:YSGG laser (Ra value of machined surface = 1.034, SLA surface = 1.380, femtosecond laser surface = 1.437, and p = 0.025) groups. On femtosecond laser-treated titanium implant surfaces, all three treatment methods significantly reduced the surface contact angle (control = 82.2°, diode laser = 74.3°, Er,Cr:YSGG laser = 73.8°, electrocautery = 76.2°, and p = 0.039). Overall, Er,Cr:YSGG laser and electrocautery treatments significantly altered the surface roughness of titanium implant surfaces. As a result of surface composition after different peri-implantitis treatment methods, relative to the diode laser and electrocautery, the Er,Cr:YSGG laser increased oxygen concentration. The most dramatic change was observed after Er:Cr;YSGG laser treatment, urging caution for clinical applications. Changes in surface composition and wettability were observed but were not statistically significant. Further research is needed to understand the biological implications of these peri-implantitis treatment methods.

Comparison of Osseointegration of Dental Implants Placed in Rabbit Tibia Using Two Dental Laser and Implant Handpiece Systems.

The present study aimed to confirm the usefulness of a multi-laser handpiece system currently under development. Implants were placed in the tibia of rabbits using a conventional separate laser-implant handpiece system (control group; SurgicPro+; NSK, Kanuma, Japan and Epic 10; Biolase, Irvine, CA, USA) and a multi-laser handpiece system (experimental group; BLP 10; Saeshin, Daegu, Korea). Implants were placed in left and right tibias of five rabbits using a conventional laser-implant handpiece system and a multi-laser handpiece system (N = 5 per group). Subsequently, micro-computed tomography (micro-CT; bone-to-implant contact evaluation), implant stability quotient (ISQ) measurement, and histological evaluations were performed to confirm the implant placement results. The independent t-test and the paired t-test were used to compare the ISQ values and the results of the two implant-laser handpiece groups (α = 0.05), respectively. No statistically significant difference in micro-CT, ISQ, and histological evaluations was observed between implant placement by the two systems (p > 0.05) except implant initial stability. The use of the multi-laser handpiece system is expected to produce the same results as a conventional separate laser-implant handpiece system with the higher implant initial stability. Additionally, it will potentially make the clinical environment more pleasant and will provide convenience for the clinicians.

A Comparative Immunohistochemical Study of Wound Healing after Dental Diode Laser Treatment in the Rat Oral Mucosa.

This study aimed to examine the differences in healing patterns using two types of diode laser devices (laser A and laser B) and a steel scalpel for periodontal surgery through histological and immunohistochemical methods. Twenty 12-week-old male rats were assigned to three groups (3, 7, and 14 days). Square-shaped erosion wounds (2 × 2 mm2 diameter) were created on the hard palate of each rat. Two wounds were created using Laser A and a steel scalpel (Bard-Parker No. 15) on the right palate and using Laser B and a steel scalpel on the left side. Rats were sacrificed after 3, 7, and 14 days. Tissues were collected with a margin of 1 mm from the border of the erosional wound of the maxillary hard palate. Histological and immunohistochemical analyses were performed on the tissue samples after 3, 7, and 14 days. The tissue healing pattern and expression of inducible nitric oxide synthase (iNOS) and cluster of differentiation (CD) were observed under a light microscope. Statistical analysis was conducted using the Kruskal−Wallis H test for comparison among the groups (α = 0.05). In comparison to the wounds made with the scalpel, wounds treated with lasers A and B showed delayed healing patterns. There was no significant difference between the two laser treatment groups (p > 0.05). The expression of iNOS and CD68 was not significantly different among the three groups after 3 and 7 days (p > 0.05). On day 14, the groups treated with the dental diode lasers showed higher expression than the group treated with the steel scalpel, but no significant difference was observed (p > 0.05). Laser-induced wounds tended to heal slower than surgical wounds performed using a steel scalpel, but histological and immunohistochemical results showed no significant difference between the dental diode laser and scalpel groups.

Effects of erythropoietin on osteoblast in the tooth extraction socket in mice periodontitis model.

Periodontitis is an excessive inflammatory event in tooth-supporting tissues and can cause tooth loss. We used erythropoietin (EPO), which has been reported to play an important role in bone healing and modulation of angiogenesis, as a therapeutic agent in vivo and in vitro experimental models to analyze its effect on periodontitis. First, EPO was applied to in vitro MC3T3-E1 cells and human periodontal ligament fibroblast (hPDLF) cells to examine its function in altered cellular events and gene expression patterns. In vitro cultivation of MC3T3-E1 and hPDLF cells with 10 IU/ml EPO at 24 and 48 h showed an obvious increase in cell proliferation. Interestingly, EPO treatment altered the expression of osteogenesis-related molecules, including alkaline phosphatase (ALP), bone morphogenetic protein-2 (BMP-2), and osteocalcin (OC) in MC3T3-E1 cells but not in hPDLF cells. In particular, MC3T3-E1 cells showed increased expression of ALP, BMP-2, and OC on day 5, while hPDLF cells showed increased expression of BMP-2, and OC on day 14. Based on the in vitro examination, we evaluated the effect of EPO on bone formation using an experimentally-induced animal periodontitis model. After the induction of periodontitis in the maxillary left second M, 10 IU/ml of EPO was locally applied to the extraction tooth sockets. Histomorphological examination using Masson's trichrome (MTC) staining showed facilitated bone formation in the EPO-treated groups after 14 days. Similarly, stronger positive reactions against vascular endothelial growth factor (VEGF), cluster of differentiation 31 (CD31), runt-related transcription factor 2 (RUNX2), and osteocalcin (OC) were detected in the EPO-treated group compared to the control. Meanwhile, myeloperoxidase, an inflammatory marker, was decreased in the EPO-treated group on days 1 and 5. Overall, EPO facilitates bone healing and regeneration through altered signaling regulation and modulation of inflammation in the osteoblast cell lineage and to a lesser extent in hPDLF cells.