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Background: This study compared the progression of experimental peri‐implantitis between alveolar ridge preservation (ARP) and spontaneous healing (SH) sites in infected (IT) and noninfected tooth (NIT). Methods: Bilateral mandibular third or fourth premolars of six beagle dogs were randomly assigned to IT and NIT groups. Before extraction, chronic dehiscence defects were created at the mesial root of mid‐buccal area in IT group. Four weeks later, the mesial roots of the third and fourth premolars were extracted in all groups.ARP procedure was randomly conducted on one side of the extraction sockets using collagenated bovine bone substitutes and resorbable collagen membrane, and contralateral side was allowded spontaneous healing. After 12 weeks of healing, bone‐level implants (ϕ 3.6 × 8.0 mm) were placed at the extraction sockets. Three months of ligature induced peri‐implantitis and three months of spontaneous progression were allowed, with radiographs taken at each phase. Biopsies were retrieved at the implant site for histomorphometric, immunohistochemical, and polarized light‐microscopic analyses. Results: Radiography demonstrated that the changes in the marginal bone level during the spontaneous progression period showed no significant differences between ARP and SH sites. Only small and/or nonsignificant differences in the progression of peri‐implantitis were observed between ARP and SH sites in histomorphometric, immunohistochemical, and polarized light microscopic analyses. Additionally, the IT and NIT groups exhibited similar outcomes for most parameters. Conclusion: ARP with xenogenic bone substitutes might provide similarly robust results as SH sites regarding the progression of experimental peri‐implantitis, irrespective of the infected or noninfected nature of the site before tooth extraction. [ABSTRACT FROM AUTHOR]

Aim: This study investigated the adjunctive effect of polydeoxyribonucleotide (PDRN) on bone formation in alveolar ridge preservation (ARP) sockets. Materials and Methods: Both mandibular second, third and fourth premolars of eight beagle dogs were randomly divided into ARP and ARP/PDRN groups. Following tooth extraction, ARP procedures were conducted using collagenized alloplastic graft material and bilayer collagen membrane soaked with normal saline (ARP group) or PDRN (ARP/PDRN group) for 10 min before application. Both groups were also randomly allocated to 2‐, 4‐ or 12‐week healing subgroups. The primary endpoint of this study was to compare histomorphometric differences between ARP and ARP/PDRN. The secondary endpoints of this study were to compare micro‐CT analysis and three‐dimensional volumetric measurement between the two groups. Results: In the histomorphometric analysis, the ARP/PDRN group exhibited greater new bone formation at coronal, middle and total position compared with the ARP group at 2‐week healing. The number of newly formed blood vessels was higher in the ARP/PDRN group than in the ARP group at 2‐ and 4‐week healing. In micro‐CT analysis, the mean new bone volume/total bone volume between ARP and ARP/PDRN was statistically significant at 2‐week healing. Ridge volume alterations were significantly decreased in the ARP/PDRN group during entire healing time compared with the ARP group, especially on the buccal side. Conclusions: The application of PDRN in ARP might provide additional benefits for early bone regeneration and maintenance of buccal ridge volume. [ABSTRACT FROM AUTHOR]

Aim: This study aimed to investigate factors influencing the survival of replaced dental implants. Materials and Methods: Charts from 2005 to 2021 were reviewed. Replaced implants after removal for the first time were identified. Depending on their survival, the replaced group was divided into the surviving and second‐removal groups. Risk factors affecting survival of replaced implants were evaluated considering clustering of multiple implants within patients. Results: The present study included 464 replaced implants of 370 patients, of which 429 and 35 implants were categorized into the surviving group and the second‐removal group. The 5‐year survival rate was 90.2 ± 0.18% in replaced implants at sites with a periodontitis history and 97.0 ± 0.15% at sites without a periodontitis history (p = 0.008). The 5‐year survival rate was 89.1 ± 0.27% in replaced implants with guided bone regeneration (GBR) at first implant placement and 93.9 ± 0.14% at non‐GBR (p = 0.032). The 5‐year survival rate was 97.6 ± 0.13% in replaced implants with GBR and 90.3 ± 0.17% in replaced implants without GBR (p = 0.026). In the multivariable analysis adjusted for clinical variables, periodontitis history (adjusted hazard ratio [aHR] = 3.417; 95% confidence interval [CI] = 1.161–10.055), GBR at first implant placement (aHR = 2.152; 95% CI = 1.052–4.397) and non‐GBR at primary implant replacement (aHR = 0.262; 95% CI = 0.088–0.778) were identified as independent risk factors for second implant removal. Conclusions: Periodontitis history, GBR at first implant placement and non‐GBR at primary implant replacement were identified as risk factors affecting the survival of replaced implants. [ABSTRACT FROM AUTHOR]

Background: Guided bone regeneration (GBR) is the most widely used technique for overcoming the deficiency of alveolar bone. However, the progression of peri‐implantitis in regenerative and pristine bone sites has not been fully investigated. The aim of this study is to compare experimental peri‐implantitis around implants placed in pristine bone and GBR sites. Methods: Bilateral mandibular first molars were extracted from six beagle dogs, and standardized horizontal ridge defect was simultaneously created at predetermined site in unilateral mandible. After 8 weeks, guided bone regeneration procedure was conducted at the defect site. After 16 weeks, implants (ϕ 3.6×8.0 mm) were placed at both extracted sites. This study included 3 months of active breakdown and another 3 months of spontaneous progression period. Radiographs were taken at each phase and specimens were obtained for histological, immunohistochemical, and polarized light microscopic analysis. Results: Marginal bone loss around implant did not show the significant differences between pristine bone and GBR sites during spontaneous progression period. In immunohistochemical analysis, inflammatory and immune‐related cells were predominantly detected in peri‐implantitis‒affected area rather than unaffected area. In the polarized light microscopic analysis, substantial reductions in the amount and thickness of collagen fibers were observed in peri‐implantitis‒affected area compared with unaffected tissues. However, there were no significant differences in histological, immunohistochemical, polarized light microscopic outcomes between pristine bone and GBR sites. Conclusion: Previous hard tissue grafting at the implant sites did not affect experimental peri‐implantitis and exhibited similar radiographic, histological, immunohistochemical, and polarized light microscopic outcomes compared with those of pristine bone sites. [ABSTRACT FROM AUTHOR]

Background: Three- dimensional (3D) technology has been suggested to overcome several limitations in guided bone regeneration (GBR) procedures because 3D-printed scaffolds can be easily molded to patient-specific bone defect site. This study aimed to investigate the effect of 3-D printed polylactic acid (PLA) scaffolds with or without hyaluronic acid (HA) in a rabbit calvaria model.Methods: A calvaria defect with a diameter of 15 mm was created in 30 New Zealand white rabbits. The rabbits were randomly allocated into three groups including no graft group (control, n = 10), 3D printed PLA graft group (3D-PLA, n = 10), and 3D printed PLA with hyaluronic acid graft group (3D-PLA/HA, n = 10). Five animals in each group were sacrificed at 4 and 12 weeks after surgery. Microcomputed tomography and histologic and histomorphometric analyses were performed.Results: Over the whole examination period, no significant adverse reactions were observed. There were no statistically significant differences in bone volume (BV) /tissue volume (TV) among the three groups at 4 weeks. However, the highest BV/TV was observed in the 3D-PLA/HA group at 12 weeks. The new bone area for control, 3D-PLA, and 3D-PLA/HA showed no statistical differences at 4 weeks. However, the value was significantly higher in the 3D-PLA and 3D-PLA/HA groups compared to the control group at 12 weeks.Conclusion: The 3D printed PLA scaffolds was biocompatible and integrated well with bone defect margin. They were also provided the proper space for new bone formation. Therefore, 3D printed PLA/HA might be a potential tool to enhance bone augmentation. [ABSTRACT FROM AUTHOR]

The cover image is based on the Original Article The adjunctive effect of polydeoxyribonucleotide on bone formation in alveolar ridge preservation: A pre‐clinical in vivo study by Young‐Chang Ko et al., https://doi.org/10.1111/jcpe.13988. [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to seek the critical time for impairment of alveolar bone regeneration after ovariectomy (OVX) in rats.Methods: A total of 32 female rats were used. Test group rats were divided into a 2M group (n = 8), a 3M group (n = 8) and a 4M group (n = 8) according to the duration from OVX to defect creation. Bilateral OVX was performed in all test groups, and a sham operation was performed in the control group (n = 8). Drill-hole defects (1.5 mm diameter, 2 mm length) were created on both sides of the maxilla. All rats were euthanized 2 and 4 weeks after the surgery. Microcomputed tomographic (micro-CT), histological, and histomorphometric analyses and in vitro experiments were performed.Results: The 4M group showed significantly less new bone formation and a lower bone mineral density than the other groups in the micro-CT analysis. The histomorphometric analysis also revealed that the 4M group showed significantly less new bone formation than the control and 2M groups. The rats in the 4M group showed significantly higher alkaline phosphatase expression levels and a larger number of calcified nodules than rats in the other groups, whereas osteoclastic activity was significantly lower in the 4M group than in the other groups.Conclusions: The critical time for impairment of alveolar bone regeneration was 4 months after OVX in rats. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to compare the survival rates of implants placed following 1-stage or 2-stage maxillary sinus floor augmentation by the lateral window technique (SFALW) performed on residual bone of <4 mm.Methods: This study was conducted based on dental records and radiographs obtained from patients who received SFALW from March 2006 to June 2014, being followed up between March 2006 and December 2017. They were divided into 1-stage and 2-stage groups according to the SFALW performed. Statistical analysis was performed to evaluate whether a significant difference existed between 1-stage and 2-stage SFALW in terms of survival rates. Multivariable logistic regression analysis was used to examine the influence of multiple variables on implant failure.Results: A total of 395 implants (156 implants in the 1-stage group, 239 implants in the 2-stage group) in 167 patients fulfilled the inclusion criteria. Among them, 13 implants (five implants in the 1-stage group, eight implants in the 2-stage group) failed. No significant difference was found in the 10-year cumulative survival rate of implants between the 1-stage group and the 2-stage group (96.8% and 92.5%, respectively, P = 0.656). Multivariable logistic regression analysis demonstrated that implant failure was significantly influenced by implant length and functional time following prosthetic loading.Conclusions: The 10-year cumulative survival rates showed no statistically significant difference between implants following 1-stage and 2-stage maxillary SFALW performed on residual bone height of <4 mm. [ABSTRACT FROM AUTHOR]

Background: This experimental study aims to evaluate the effect of hyaluronic acid on healing of infected extraction sockets compared with recombinant human bone morphogenetic protein-2 (rhBMP-2).Methods: Both third and fourth mandibular premolars of six beagle dogs were hemisected, and the distal roots were extracted at baseline. Subsequently, combined endodontic-periodontic lesions were induced at the remaining mesial roots. After 4 months, the mesial roots on both sides of the mandible were removed. Four sockets per dog were randomly allocated to four groups: Group 1, Control; Group 2, only absorbable collagen sponge (ACS: carrier); Group 3, 1% hyaluronic acid (HA) gel + ACS; and Group 4, rhBMP-2 + ACS. After 3 months of healing, the dogs were euthanized for microcomputed tomography and histologic analysis.Results: After the lesion induction period (4 months), communication between the periodontal lesion and endodontic periapical lesion was observed at all remaining mesial roots. Alveolar bone overgrowth was observed in groups 3 and 4, but bone volume density was not significantly different among all groups. At the crestal portion, mineralization, and osteocalcin expression were higher in groups 3 and 4 than in groups 1 and 2.Conclusion: Treatment with HA can promote bone formation and improve the wound healing rate comparable to rhBMP-2 in infected extraction sockets. [ABSTRACT FROM AUTHOR]

Introduction: Accurate clinical decision‐making of dentists should be based on their knowledge and experience. In the past 10 years, interest in competency‐based dentistry education has rapidly increased, but there has been little attention paid to methods of improving dental education competency. The purpose of this study was to develop a clinical presentation education model that provides opportunities for students to practice problem‐solving from the moment they greet the patient so that students can obtain the practical experience of competency‐based education and the effectiveness of this model can be confirmed through pilot test. Methods: This article is divided two parts: First, developing the clinical presentation dental education model (CPDEM) and Second, a pilot study adopted CPDEM. To confirm the effectiveness of this model, the students' satisfaction, their perception of self‐achievement were analysed. Results: Clinical presentation dental education model has been developed to provide practice‐related education experience and provide linkage between basic science and clinical science. The result of applying this education model to 10 students as a pilot test was shown an overall high satisfaction level. In addition, self‐achievement students' reported of all intended competencies was higher than for non‐participating students of this model. Conclusions: This study focuses on practical education centring on clinical presentation. This model could get a meaningful and realistic experiences through the practice using clinical presentation of patients, use their metacognition for organizing and memorizing the patient's case by using concept map. It can be used as a future instructional method to enhance students' competency. [ABSTRACT FROM AUTHOR]

Background: This study evaluates occurrence of progressive bone loss (PBL) around implants with different implant surfaces.Methods: Retrospective examination of 2,517 implants was performed in 903 patients, including 1,147 anodized-surface implants in 454 patients and 1,370 resorbable blasting media (RBM)-surface implants in 449 patients, which were placed from January 2006 to December 2010. Through regular check-up radiographs and records, presence of PBL (up to >50% of fixture length) was investigated. Implant removal for any reason was regarded a failure.Results: In total, 2,186 implants (979 anodized implants and 1,207 RBM implants) in 793 patients were included in this study. PBL was more frequently observed among anodized implants (n = 36 in 21 patients; 4%) than among RBM implants (n = 19 in 14 patients; 2%), and this difference was statistically significant (P <0.001). Occurrence of PBL was significantly influenced by surface modification and implant diameter (odds ratio [OR] of anodized surface = 4.40, 95% confidence interval [CI] = 1.78 to 10.89, P = 0.001; OR of wide implants = 9.62, 95% CI = 1.13 to 81.68, P = 0.038; determined by mixed-effects logistic regression analysis with random patient effect). However, total survival rate was significantly influenced by implant diameter and not by surface modification (P = 0.019), although effect of implant diameter was observed to be significant on anodized implants (P = 0.030).Conclusion: Implant surface modification and implant diameter are significantly associated with occurrence of PBL. [ABSTRACT FROM AUTHOR]

Objectives: This 12‐week clinical trial evaluated efficacy and adverse events for two recombinant human bone morphogenetic protein‐2 (rhBMP‐2) delivery systems in alveolar ridge preservation. Materials and methods: Sixty‐four patients had a single tooth that required replacement with an implant, surrounded by > 50% alveolar bone height. Two cohorts (n = 32 patients each) were randomized to receive a rhBMP‐2‐soaked absorbable collagen sponge (test group), or β‐tricalcium phosphate and hydroxyapatite particles (control group) immersed in rhBMP‐2, at the implant site. Bone height and width changes at 25%, 50%, and 75% of extraction socket level (ESL) were compared. Adverse events were assessed in the same period. In addition to the randomized controlled clinical trial, histological analysis of 21 patients (test group [n = 12], control group [n = 9]) was conducted, 4 months after alveolar ridge preservation. A non‐inferiority test was used to analyze changes in alveolar bone height between groups (p = 0.05). A Wilcoxon rank‐sum test was used to analyze changes in alveolar bone width and histomorphometric results between groups (p = 0.05). Results: All patients showed good healing without severe adverse events. The lower limit of the one‐sided 97.5% confidence interval in the difference between the two groups was 0.0033 (non‐inferiority margin: −0.185); thus, the test group showed non‐inferiority to the control group. Wilcoxon rank‐sum test analysis did not show statistically significant differences between groups with regard to changes in alveolar bone width and histomorphometric analysis. Conclusions: The delivery systems showed similar efficacy for alveolar ridge preservation without severe adverse events. [ABSTRACT FROM AUTHOR]

Background: There have been previous studies on the relationship between periodontitis and peri-implantitis, but limited information is available on how periodontitis affects osseointegration and wound healing of newly placed dental implants adjacent to natural teeth. The objective of the present experiment is to evaluate healing around dental implants adjacent to teeth with untreated experimental periodontitis.Methods: The study included six male beagle dogs. Scaling and plaque control procedures were performed on three dogs (control group). In the other three dogs (experimental group), retraction cords and ligature wires were placed subgingivally around all premolars and the first molars. Induced experimental periodontitis was confirmed after 3 months. Each control or experimental group was divided into two subgroups depending on the timing of implant placement (immediate/delayed). Twelve dental implants (two implants for each dog) were placed immediately, and the other 12 dental implants (two implants for each dog) were placed 2 months after extraction. The animals were sacrificed 2 months after implant placement. Histologic and histometric analyses were performed.Results: Four implants (three from the immediate placement group and one from the delayed placement group) failed in the experimental group. There were significant differences in the percentage of bone-to-implant contact and marginal bone volume density between the control and experimental groups. Both parameters were significantly lower in the experimental group than in the control group (P <0.05). There was a tendency toward more marginal bone loss in the experimental group than the control group.Conclusions: Immediate placement of implants is associated with a higher failure rate compared with delayed placement. Untreated experimental periodontitis was correlated with compromised osseointegration in the implants with delayed placement. [ABSTRACT FROM AUTHOR]

Background: Pain from local anesthetic injection makes patients anxious when visiting a dental clinic. This study aims to determine differences in pain according to types of local anesthetizing methods and to identify the possible contributing factors (e.g., dental anxiety, stress, and sex).Methods: Thirty-one patients who underwent open-flap debridement in maxillary premolar and molar areas during treatment for chronic periodontitis were evaluated for this study. A randomized, split-mouth, single-masked clinical trial was implemented. The dental anxiety scale (DAS) and perceived stress scale (PSS) were administered before surgery. Two lidocaine ampules for each patient were used for local infiltration anesthesia (supraperiosteal injection). Injection pain was measured immediately after local infiltration anesthesia using the visual analog pain scale (VAS) questionnaire. Results from the questionnaire were used to assess degree of pain patients feel when a conventional local anesthetic technique (CNV) is used compared with a computer-controlled anesthetic delivery system (CNR).Results: DAS and PSS did not correlate to injection pain. VAS scores were lower for CNR than for CNV regardless of the order in which anesthetic procedures were applied. VAS score did not differ significantly with sex. Pearson coefficient for correlation between VAS scores for the two procedures was 0.80, also indicating a strong correlation.Conclusion: Within the limitations of the present study, relief from injection pain is observed using CNR. [ABSTRACT FROM AUTHOR]

Background: In previous studies by the authors, it was demonstrated that a fibronectin (FN)-derived oligopeptide, termed F20, stimulates osteoblast differentiation in vitro and bone formation in vivo. However, the fundamental molecular mechanism by which F20 stimulates osteogenesis remains unknown. Therefore, in this study the molecular mechanism underlying the effect of F20 in osteoblast differentiation is investigated.Methods: The role of F20 in osteoblast differentiation was examined using mouse bone-marrow-derived ST2 cell line. The effect of Smad1/5 was determined following small interfering RNA knockdown. Runt-related transcription factor (Runx) 2, alkaline phosphatase (Alp), and osteocalcin (Oc) mRNA levels were determined by quantitative real-time polymerase chain reaction, and their transcriptional activation was assessed using luciferase reporter assays. Extracellular signal-regulated kinase (ERK) phosphorylation was visualized via immunoblotting.Results: Synthetic oligopeptide F20 stimulated expression of bone marker genes Runx2, Alp, and Oc in ST2 cells via Smad and ERK or mitogen-activated protein kinase signaling pathways as did bone morphogenic protein 2 (BMP2). Furthermore, Runx2 acted as a transcription factor during F20-induced osteoblast differentiation.Conclusions: Collectively, these results indicate that F20 induces osteoblast differentiation with a pattern similar to that mediated by BMP2 signaling pathway. The authors' previous data also showed that FN-derived oligopeptide improved wound healing, and it is suggested that F20 might serve as a therapeutic biomolecule to facilitate periodontal tissue regeneration. [ABSTRACT FROM AUTHOR]

Material is a crucial factor for the restoration of the tooth or periodontal structure in dentistry. Various biomaterials have been developed and clinically applied for improved periodontal tissue regeneration and osseointegration, especially in periodontology and dental implantology. Furthermore, the biomimetic approach has been the subject of active research in recent years. In this review, the most widely studied biomaterials (bone graft material, barrier membrane, and growth or differentiation factors) and biomimetic approaches to obtain optimal tissue regeneration by making the environment almost similar to that of the extracellular matrix are discussed and specifically highlighted. [ABSTRACT FROM AUTHOR]

Objectives The aim of this study was to evaluate the validity of the immediate peri-implantitis model to test regenerative therapies in peri-implantitis defects. Material and methods In an immediate peri-implantitis model in beagles, the mandibular third premolars were extracted, and dental implants were immediately placed in the distal extraction sockets. Without a healing period, experimental peri-implantitis was induced by ligature placement for 3 months. In the conventional peri-implantitis model, dental implants were placed in the healed mandibular fourth premolar region and were submerged for osseointegration. After 3 months of healing, peri-implantitis induction was performed for another 3 months. After peri-implantitis defects were formed in both models, regenerative therapy was performed in both models. Results After 3 months in the immediate model and 9 months in the conventional model, similarly shaped horizontal bone defects (wide and craterlike) were observed. However, buccal bone defects were deeply formed in the immediate model compared with the conventional model (6.02 ± 1.20 and 4.34 ± 0.86 mm, respectively; P = 0.009), but the amounts of bone regeneration were not significantly different between the models ( P = 0.107). On the lingual side, re-osseointegration was significantly greater in the conventional model than in the immediate model (0.72 ± 0.50 and 1.77 ± 0.87 mm, respectively; P = 0.009), although lingual bone defects were not significantly different between the models ( P = 0.248). Conclusions Although the immediate peri-implantitis model is challenging for regeneration, it may be able to replace the conventional model to study regenerative peri-implantitis treatment due to its short experimental time and similar defect configuration. [ABSTRACT FROM AUTHOR]

Objectives: The objective of this study was to evaluate bone formation/osseointegration following surgical treatment of experimental peri-implantitis at dental implants with different surface characteristics exposed to ligature-induced breakdown conditions. Methods: Ten turned (control), 10 sandblasted/acid-etched (SA), and 10 SA/hydroxyapatite nanocoated (HA) implants were installed into the edentulated posterior mandible in five Beagle dogs and allowed to osseointegrate for 12 weeks. Ligature-induced breakdown defects were then induced over 23 weeks using stainless steel wire ligatures. The ligatures were removed and soft tissues were allowed to heal for 3 weeks. Next, exposed implant surfaces were decontaminated followed by guided bone regeneration using a collagen membrane and submerged wound healing. The animals were euthanized for histometric analysis at 12 weeks post-surgery. Results: The radiographic analysis showed vertical bone loss following ligatureinduced breakdown without statistically significant differences among implant technologies. The histometric analysis showed significantly enhanced bone formation (height) at SA and SA/HA compared with turned implants (p = 0.028) following reconstructive surgery. Bone formation area was greater at SA/HA compared with turned implants, however the difference did not reach statistical significance. Conclusions: While ligature-induced defect progression does not appear implant surface dependent in this animal model, bone formation at the decontaminated implant surfaces appears more favourable at SA and SA/HA over turned implants following reconstructive surgery. [ABSTRACT FROM AUTHOR]

Peri-implantitis is a chronic inflammatory process with advanced bone loss and impaired healing potential. For peri-implantitis treatment, tissue engineering can be applied to enhance bone regeneration of peri-implant defects. This study aimed to evaluate ex vivo bone morphogenetic protein 2 (BMP2) gene delivery using canine periodontal ligament stem cells (PDLSCs) for regeneration of peri-implantitis defects. Canine PDLSCs were transduced with adenoviral vectors containing BMP2 (BMP2/PDLSCs). After peri-implantitis was induced by ligature placement in six beagle dogs, regenerative procedures were performed; hydroxyapatite (HA) particles and collagen gel with autologous canine PDLSCs (PDLSC group) or BMP2/PDLSCs (BMP/PDLSC group) or without cells (control group) were grafted into the defects and covered by an absorbable membrane. Three months later, the animals were sacrificed. In vitro, BMP2/PDLSCs showed similar levels of stem cell properties to PDLSCs, such as colony-forming efficiency and expression of MSC markers STRO-1 and CD 146. BMP2/PDLSCs produced BMP-2 until day 21 at a concentration of 4-8 ng/mL. In vivo, the BMP2/PDLSC group showed significantly more new bone formation and re-osseointegration in peri-implantitis defects compared to the other groups. In conclusion, ex vivo BMP2 gene delivery using PDLSCs enhanced new bone formation and re-osseointegration in peri-implantitis defects. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 38-47, 2015. [ABSTRACT FROM AUTHOR]

Background: This study evaluates the potential of bone morphogenetic protein 2 (BMP-2) gene-transduced bone marrow stem cells (BMSCs) to facilitate osseous healing after rabbit maxillary sinus augmentation in conjunction with implant placement. Methods: Autologous BMSCs derived from New Zealand white rabbits were cultured and transduced with BMP-2 using an adenovirus vector. Transduced BMSCs (BMP-2/ BMSCs) were then combined with a deproteinized bovine bone mineral (DBBM) scaffold. Twenty-seven animals were randomly allocated into three groups: 1) control, sinus grafted with DBBM alone; 2) BMSC, sinus grafted with non- transduced BMSCs and DBBM; and 3) BMP-2/BMSC, sinus grafted with BMP-2/BMSCs and DBBM. During these procedures, a mini-implant was placed in the floor of the sinus. Animals were sacrificed at 2, 4, and 8 weeks after surgery. New bone area and bone-to-implant contact (BIC) were evaluated histomorphometrically. Results: At 2 and 4 weeks, the BMP-2/BMSC group showed more new bone area and higher BIC than the other two groups. BMP-2/BMSCs were detected with confocal microscopy for up to 4 weeks, which indicates that transduced cells contributed to new bone formation. However, at 8 weeks, there was no difference in new bone area or BIC among the three groups. Conclusions: These results suggest that BMP-2 delivery using BMSCs may result in earlier and increased bone formation in the maxillary sinus. This finding may offer more stable bone support to implants and reduce healing times. However, this study also revealed limitations in the stimulatory effect of BMP-2/BMSCs, such as diminished activity over time in later healing stages. [ABSTRACT FROM AUTHOR]

Poly(L‐lactic acid) (PLLA) microfibrous scaffolds with three‐dimensional (3D) structures were fabricated using an electrospinning technique with a subsequent mechanical expansion process. To achieve a 3D fibrous structure, the fusion at the contact points of the as‐spun PLLA microfibers was avoided using an appropriate binary solvent system of methylene chloride and acetone. The solvent composition was optimized based on the solvent power, volatility, and viscosity (methylene chloride:acetone = 9:1 volume ratio). The final 3D structure of the electrospun scaffolds was obtained after mechanical expansion of the electrospun microfibrous mats. The pore sizes of the scaffolds were controlled by varying the degree of expansion of the nonbonded microfibrous mats, and they were in the range of several microns up to 400 μm. The 3D scaffolds were examined for their morphological properties and their potential use for the proliferation of osteoblasts. Generally recognized electrospun 2D nanofibrous membranes were also tested in order to compare the cell behaviors using different scaffold geometries. The 3D scaffolds demonstrated a high level of osteoblast proliferation (1.8‐fold higher than nanofibrous membranes in a week). The osteoblasts actively penetrated the inside of the 3D scaffold and showed a spatial cell distribution, as confirmed by SEM and H&E staining, while a monolayer formed in the case of the 2D nanofibrous membranes with limited cell infiltration. In vivo results further showed that 3D electrospun microfibrous matrices were a favorable substrate for cell infiltration and bone formation after 2 and 4 weeks, using a rabbit calvarial defect model. In this study, the 3D microfibrous PLLA scaffolds fabricated using electrospinning techniques might be an innovative addition to tissue engineering applications. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010. [ABSTRACT FROM AUTHOR]

At present, limited functional data exists regarding the application and use of biomechanical and imaging technologies for oral implant osseointegration assessment. The objective of this investigation was to determine the functional apparent moduli (FAMs) that could predict the dynamics of oral implant osseointegration. Using an in vivo dental implant osseous healing model, two FAMs, functional bone apparent modulus (FBAM), and composite tissue apparent modulus (FCAM), of the selected peri‐implant structures were calculated via microcomputed tomography (micro‐CT) and finite element (FE) simulations in order to support this concept. Results showed significant sensitivity between FAMs and micro‐CT parameters, especially between bone mineral density and FBAM, while at extraction defect sites the strongest correlations existed between bone‐implant contact and FCAM. Significant enhancement of FCAM indicated progressive functional repair during early osseointegration. Further, the resultant interfacial resistance was predicted by bone mineral content (BMC) and FBAM within a ∼200 μm peri‐implant thickness, while the extraction defects gave zones of ∼575 μm and 200 μm for BMC and FCAM, respectively. These results suggest that the function of dental implant support can be predicted from a peri‐implant structural zone. We conclude that FAMs can be used to predict the dynamics of dental implant osseointegration in vivo. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010 [ABSTRACT FROM AUTHOR]

The evaluations of the fibers characteristics, bioactivity, pre‐osteoblastic cell responses, and osteoconductivity of the non‐woven SiO2–CaO gel fabric made by electrospinning method was carried out. Silica gels with four different calcium contents were prepared by condensation following hydrolysis of tetraethyl orthosilicate under acidic conditions. The molar ratios of Ca to Si prepared ranged from 0 to 0.15. SiO2–CaO gel fabrics were heat‐treated at 300°C for 3 h after spinning under an electric field of 2 kV/cm. As the Ca to Si ratio increased, the diameter of electrospun SiO2–CaO gel fibers increased because the viscosity of the SiO2–CaO gel solution increased. The apatite‐forming ability of heat‐treated, non‐woven SiO2–CaO gel fabric was evaluated in simulated body fluid and tended to increase with an increasing Ca to Si molar ratio. However, proliferation and differentiation tended to decrease with an increasing Ca to Si molar ratio. The sample which had the Ca to Si ratio as 0.10 showed good osteoconductivity in vivo in the calvarial defect New Zealand white rabbit model compared to that had the Ca to Si ratio as 0 and empty defect. These results strongly suggest that non‐woven SiO2–CaO gel fabric made by the electrospinning method has potential for application as a bone grafting material. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009 [ABSTRACT FROM AUTHOR]

Two cell-binding domains from FGF-2 (fibroblast growth factor-2) were shown to increase cell attachment and osteoblastic differentiation. Two synthetic peptides derived from FGF-2, namely residues 36-41 (F36; PDGRVD) and 77-83 (F77; KEDGRLL), were prepared and their N-termini further modified for ease of surface immobilization. Chitosan membranes were used in the present study as mechanical supportive biomaterials for peptide immobilization. Peptides could be stably immobilized on to the surface of chitosan membranes. The adhesion of mesenchymal stem cells to the peptide (F36 and F77)-immobilized chitosan membrane was increased in a dose-dependent manner and completely inhibited by soluble RGD (Arg-Gly-Asp) and anti-integrin antibody, indicating the existence of an interaction between F36/F77 and integrin. Peptide-immobilized chitosan supported human bone-marrow-derived mesenchymal-stem-cell differentiation into osteoblastic cells, as demonstrated by alkaline phosphate expression and mineralization. Taken together, the identified peptide-immobilized chitosan membranes were able to support cell adhesion and osteoblastic differentiation; thus these peptides might be useful as bioactive agents for osteoblastic differentiation and surface-modification tools in bone regenerative therapy. [ABSTRACT FROM AUTHOR]

Fibroblast growth factor (FGF)‐2 regulates a variety of cellular functions, such as proliferation and differentiation, by binding to cell surface FGF receptors (FGFRs) in the presence of heparin proteoglycans. FGF‐2 is known as a heparin‐binding growth factor, but the localization of the heparin binding site has not been fully investigated until now. We used two potential heparin binding domains of FGF‐2, the residues 105–111 (F105, YKRSRYT) and 119–135 (F119, KRTGQYKLGSKTGPGQK). Peptides could be stably immobilized onto the surface of tissue culture plates. Using solid phase binding assays, we demonstrated that both peptides had higher binding affinity toward heparin compared with nonbinding control sequence. The biological significance of these sites was tested by cell attachment and osteoblast differentiation studies. Cell attachment to the peptides F105 and F119 increased in a dose‐dependent manner. Heparin and heparinase treatments decreased cell adhesion to both F105 and F119. This demonstrates that both F105 and F119 interact with cell‐surface heparan sulfate proteoglycans, suggesting that FGF‐2 has two heparin binding sites. In addition, osteoblast differentiation, confirmed by ALPase activity and mineralization, was increased by surface immobilized peptide F105 and F119. Taken together, these heparin binding peptides could be applied as biological agents enhancing osteoblast differentiation as well as surface modification tools in the tissue regeneration area, especially for bone regeneration. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007 [ABSTRACT FROM AUTHOR]

Background: Recombinant human bone morphogenetic protein (rhBMP)-2 has been shown to stimulate significant regeneration of alveolar bone and cementum in periodontal defects clinically. The aim of this study was to evaluate the osteopromotive effect of oligopeptide domain-coated bovine bone mineral granules in a rabbit calvarial defect model. Methods: The peptide-coated bovine bone was fabricated by incubating the graft material in a solution of oligopeptide domain. The cell attachment and proliferation were measured in vitro. Peptide-coated (test group) or uncoated (control group) bone minerals were implanted into 10-mm calvarial defects in rabbits, and the animals were sacrificed at 1, 2, or 4 weeks post-surgery. Results: The cells grown with peptide-coated bone showed significantly higher proliferation activity at all times compared to cells grown with peptide-uncoated bone mineral. At 2 weeks post-surgery, the control wounds showed a limited amount of osteoid formation in a centripetal pattern around the grafted bone, but the oligopeptide domain-coated grafted bone had formed new bone around the grafted area. At 4 weeks post-surgery, the control sites showed increased new bone formation, but they still showed a significant difference from the peptide-coated bone-implanted sites. Conclusions: At 2 and 4 weeks, accelerated new bone formation was observed within the experimental sites compared to control groups. The use of deproteinized bovine bone combined with a synthetic oligopeptide seems to be a more beneficial material for bone regeneration in the early healing period. [ABSTRACT FROM AUTHOR]

Background: Objectives of the study‐ to examine the effect of synthetic FN fragments including fibrin binding sites on migration of osteoblast‐like cells via in vitro scratch assay. Aim/Hypothesis: Fibrin‐binding oligopeptides, 100 μM of FF3 and FF5, derived from FN enhanced the migration rate of MC3T3‐E1 osteoblast‐like cells in in vitro wound healing model and these peptides can be applied to enhance the early wound healing capacity of biomaterials inserted into a bone. Material and Methods: MC3T3‐E1 osteoblast‐like cells Synthetic oligopeptide FF1 (CYDNGKHYQ), FF3 (CFDKYTGNTYR), FF5 (CTSRNRCNDQ) ‐ diluted to 50, 100 and 150 μM ‐ coated to 4‐well cell culture plate Scratch wound assay ‐ 1 × 10_SP_5_sp_ cells well ‐ parallel scratches with 200 μl plastic pipette tips ‐ pretreated with mitomycin C (30 μg mL) 1 hour before wounding Fixation and Staining ‐ 14, 20 hours after wounding with Multiple stain Migration rate (%) = area of migrated cells (A) cell free area (A+B). Results: All peptide groups except 150 μM showed statistically significant increase in migration rate at 14 hours. At 20 hours all experimental groups of 100 μM and FF1 of 150 μM concentration were significantly improved the scratch closure. Conclusions and Clinical Implications: Significantly increased migration was observed at type I repeats 2–5 fibrin‐binding fragments of FN – FF3 and FF5 ‐ added MC3T3‐E1 cells. Optimum concentration was 100 μM. The biologic effect of fibrin‐binding oligopeptide in this study supports the FN's essential contribution in bone regeneration as a temporary scaffold in FN‐fibrin matrix. [ABSTRACT FROM AUTHOR]

Bone morphogenetic proteins (BMPs) play a pivotal role in inducing undifferentiated cells into osteoblastic cells that induce bone formation. [ABSTRACT FROM AUTHOR]

Background: Non‐thermal plasma discharges are applied to the sterilization of surgical instruments and the decontamination of microorganisms recently. The Atmosphere Pressure Plasma Jet (APPJ), one of the Dielectric Barrier Discharges (DBD), can be a promising tool for the non‐thermal bacteria sterilization due to high amount of radical generation. Aim/Hypothesis: The aim of this study was to evaluate the in vitro antibacterial activity of APPJ as an effective approach against periodontal pathogen. Material and Methods: To evaluate antibacterial activity, the viability and morphology of Porphyromonas gingivalis (_I_P. gingivalis_i_) were investigated after expose to APPJ. _I_P. gingivalis_i_ was inoculated in 96 well multiplate and exposed to APPJ for 10, 30, 60 and 180 seconds, and then the viability and morphology were measured. The bacteria was incubated on Ti disc and in chamber slides for 3 days to form biofilm and exposed to APPJ for 1, 3 and 5 minutes, and then adhesion aspect of the bacteria were investigated with SEM and CLSM. Results: Treatment with APPJ reduced the quantity of _I_P. gingivalis_i_ all exposure times. In addition, in TEM images, the most cells showed that the cytoplasmic contents were completely leaked out after expose to APPJ for 5 minutes, leaving two distinct membranes. In SEM images, little bacteria was detected on Ti disc after treatment for 3 minutes with APPJ. In CLSM images, dead cells were increased over times and little dead cells were investigated after treatment for 5 minutes. Conclusions and Clinical Implications: The present results demonstrated that APPJ were effective for killing _I_P. gingivalis_i_ and removing biofilm on culture dish and Ti disc. The results suggest the potential of APPJ for antimicrobial applications in dentistry. In particular, the disinfection of biofilm‐contaminated microstructured Ti implant surface may be a promising option. In this context, APPJ could provide a novel approach used in combination with surgical treatment. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article titled "Functional apparent moduli as predictors of oral implant osseointegration dynamics" published in the Journal of Biomedical Materials Research. The correction addresses an error in the affiliations listed for one of the authors, Yang-Jo Seol. The correct affiliations for all authors are provided in the notice. The authors apologize for any confusion caused by the error. [Extracted from the article]

Aim: The aim of the present study was to investigate bone regeneration following ex vivo bone morphogenetic protein-2 (BMP-2) gene delivery using human gingival fibroblasts (HGFs) in rat calvarial defects., Materials and Methods: An 8 mm craniotomy defect was created in Sprague-Dawley rats. The animals were divided into four groups: (1) non-grafted group, the defect was left empty; (2) collagen matrix group, the defect was filled with collagen matrix only; (3) HGF group, the defect was filled with non-transduced HGFs on collagen matrix; (4) BMP-2/HGF group, the defect was filled with BMP-2 gene-transduced HGFs on collagen matrix. Animals were sacrificed at 2 and 4 weeks after surgery, and micro-computed tomographic and histologic observations were performed., Results: The BMP-2/HGF group showed promoted osseous healing of calvarial defects, as compared with the other groups. At both 2 and 4 weeks, regenerated bone area was significantly greater in the BMP-2/HGF group than the other three groups. Quite a few number of transplanted HGFs were observed within the regenerated bone tissues., Conclusions: The results of this study suggest that ex vivo BMP-2 gene delivery induces prominent bone regeneration in vivo and HGFs may be useful as target cells for ex vivo gene therapy.

The aim of the present study was to test the osteogenic effects of BMP-2 (bone morphogenetic protein-2) gene transfer in BMSCs (bone-marrow stromal cells) and rabbit calvarial bone defects. The pBMP-2-cDNA3.1 plasmid was constructed by subcloning hBMP-2 (human BMP-2) cDNA into the plasmid pcDNA3.1. BMSCs were transfected with a pBMP-2-cDNA3.1-Lipofect-amine complex. Transfected cells were observed for localization of the BMP-2 coding plasmid. Also, the level of BMP-2 in the culture medium of transfected cells was measured. The culture medium was collected and we tested whether this medium could induce non-transfected BMSCs to express ALP (alkaline phosphatase) and osteocalcin. The pBMP-2-cDNA3.1 complexes were incorporated into the collagen scaffold and the plasmid-loaded collagen scaffolds were then grafted into rabbit calvarial defects. After 2 weeks, granulation tissue at the grafted site was obtained and mRNA of BMP-2 was examined via RT (reverse transcriptase)--PCR. After 4 and 8 weeks, the animals were killed and the calvarial tissue was excised. After specimen preparation, optical microscopical examination was performed to evaluate bone formation. The results show that transfected cells were able to incorporate the BMP-2 gene into their nuclei. Also, the level of expressed and secreted BMP-2 was significantly higher in transfected cells than in untransfected cells (P<0.01). The retrieved culture medium could induce the expression of ALP and osteocalcin in non-transfected BMSCs. hBMP-2 mRNA was detected at the granulation tissue of experimental animals, but not in control animals after 2 weeks. At both 4 and 8 weeks, experimental groups showed significantly more newly formed bone area than the control group (P<0.01). Therefore pBMP-2-cDNA3.1 gene delivery could induce BMSCs into osteoblastic phenotype cells and enhance bone regeneration in rabbit calvarial bone defects.