• Maxillofacial Plastic and Reconstructive Surgery
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• v.38
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• pp.14.1-14.6
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• 2016

Background: In guided bone regeneration (GBR) technique, many materials have been used for improving biological effectiveness by adding on membranes. The new membrane which was constructed with chitin-fibroin-hydroxyapatite (CNF/HAP) was compared with a collagen membrane (Bio-$Gide^{(R)}$) by means of micro-computed tomography. Methods: Fifty-four rats were used in this study. A critical-sized (8 mm) bony defect was created in the calvaria with a trephine bur. The CNF/HAP membrane was prepared by thermally induced phase separation. In the experimental group (n = 18), the CNF/HAP membrane was used to cover the bony defect, and in the control group (n = 18), a resorbable collagen membrane (Bio-$Gide^{(R)}$) was used. In the negative control group (n = 18), no membrane was used. In each group, six animals were euthanized at 2, 4, and 8 weeks after surgery. The specimens were analyzed using micro-CT. Results: Bone volume (BV) and bone mineral density (BMD) of the new bone showed significant difference between the negative control group and membrane groups (P < 0.05). However, between two membranes, the difference was not significant. Conclusions: The CNF/HAP membrane has significant effect on the new bone formation and has the potential to be applied for guided bone regeneration.

• Archives of Plastic Surgery
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• v.42 no.2
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• pp.179-185
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• 2015

Background Capsular contracture is the most troublesome complication in breast implant surgery. Although capsule formation can be seen as a normal reaction to a foreign body, it can induce pain, hardness, deformity, and other pathologic problems. Surgical intervention is required in severe cases, but even surgery cannot guarantee a successful outcome without recurrence. This experimental study confirms that single topical administration of leukotriene antagonist zafirlukast (Accolate, Astrazeneca) reduces peri-implant capsule formation and prevents capsular contracture. Methods Twelve smooth-surfaced cohesive gel implants were implanted in New Zealand White rabbits. These miniature implants were designed to be identical to currently used products for breast augmentation. The rabbits were divided into 2 groups. In the experimental group (n=6), the implant and normal saline with zafirlukast were inserted in the submuscular pocket. In the control group (n=6), the implant and normal saline alone were used. Two months later, the implants with peri-implant capsule were excised. We evaluated capsule thickness and collagen pattern and performed immunohistochemical staining of myofibroblasts, transforming growth factor $(TGF)-{\beta}1$, 2. Results The thickness of the capsules in the experimental group was reduced in both dorsal and ventral directions. The collagen pattern showed parallel alignment with low density, and the number of myofibroblasts as well as the amounts of $TGF-{\beta}1$ and $TGF-{\beta}2$ were reduced in the experimental group. Conclusions We suggest that single topical administration of leukotriene antagonist zafirlukast can be helpful in reducing capsule formation and preventing capsular contracture via myofibroblast suppression, modulation of fibroblastic cytokines, and anti-inflammatory effect.

• Journal of Periodontal and Implant Science
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• v.41 no.5
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• pp.253-258
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• 2011

Purpose: Immediate implantation presents challenges regarding site healing, osseointegration, and obtaining complete soft-tissue coverage of the extraction socket, especially in the posterior area. This last issue is addressed herein using the double-membrane (collagen membrane+high-density polytetrafluoroethylene [dPTFE] membrane) technique in two clinical cases of posterior immediate implant placement. Methods: An implant was placed immediately after atraumatically extracting the maxillary posterior tooth. The gap between the coronal portion of the fixture and the adjacent bony walls was filled with allograft material. In addition, a collagen membrane (lower) and dPTFE membrane (upper) were placed in a layer-by-layer manner to enable the closure of the extraction socket without a primary flap closure, thus facilitating the preservation of keratinized mucosa. The upper dPTFE membrane was left exposed for 4 weeks, after which the membrane was gently removed using forceps without flap elevation. Results: There was considerable plaque deposition on the outer surface of the dPTFE membrane but not on the inner surface. Moreover, scanning electron microscopy of the removed membrane revealed only a small amount of bacteria on the inner surface of the membrane. The peri-implant tissue was favorable both clinically and radiographically after a conventional dental-implant healing period. Conclusions: Secondary closure of the extraction socket and immediate guided bone regeneration using the double-membrane technique may produce a good clinical outcome after immediate placement of a dental implant in the posterior area.

• Biomedical Science Letters
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• v.16 no.4
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• pp.365-376
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• 2010

The purpose of this study was to clarify the effect of light emitting diode (LED) irradiation on healing of impaired wound and alteration of mast cells in experimental diabetic rats. Twenty-four male Sprague-Dawley rats were divided into four groups: excision (Ex), excision-LED irradiation (Ex-LED), diabetes + excision (DM) and diabetes + excision + LED irradiation (DM-LED). Diabetes was induced in rats by streptozotocin (STZ) injection (70 mg/kg, single dose) and 6 mm punch excision wounds were created on the back after shaving hair. The LED-irradiated rats were treated to a daily dose of $5\;J/cm^2$ LED (630 nm) light for 11 days after surgery, and were killed at day 1, 3, 7 and 11. The lesion and adjacent skin tissues were excised, fixed with 10% buffered formalin and embedded with paraffin. For evaluation of wound healing, hematoxylin-eosin (HE) and Masson trichrome staining were performed. Mast cells (MCs) were stained with toluidine blue (pH 0.5) and quantified using a computerized image analysis system. The proliferation activity of keratinocyte in skin tissues was analyzed on sections immunostained with proliferative cell nuclear antigen (PCNA). The results showed that wound healing rate, collagen density and neo-epidermis length, number of PCNA-positive cells, fibroblasts and mast cells were significantly higher in the LED-irradiated rats than in the DM and Ex rats throughout the periods of experiment. Exceptionally, the number of MCs was significantly lower at day 11 compared with day 7 after surgery in the all groups. These findings suggest that the LED irradiation may promote the tissue repair process by accelerating keratinocyte and fibroblast proliferation and collagen production in normal rats as well as in diabetic rats, and MCs may play an important role at an early stage of skin wound healing in normal and diabetic rats.

• Journal of Periodontal and Implant Science
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• v.50 no.6
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• pp.418-434
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• 2020

Purpose: The purpose of the present study was to evaluate the effect of silica-calcium phosphate composite (SCPC) granules on bone regeneration in extraction sockets. Methods: Ten patients were selected for a split-model study. In each patient, bone healing in SCPC-grafted and control ungrafted sockets was analyzed through clinical, radiographic, histomorphometric, and immunohistochemical assessments 6 months postoperatively. Results: A radiographic assessment using cone-beam computed tomography showed minimal ridge dimension changes in SCPC-grafted sockets, with 0.39 mm and 1.79 mm decreases in height and width, respectively. Core bone biopsy samples were obtained 6 months post-extraction during implant placement and analyzed. The average percent areas occupied by mature bone, woven bone, and remnant particles in the SCPC-grafted sockets were 41.3%±12%, 20.1%±9.5%, and 5.3%±4.4%, respectively. The percent areas of mature bone and woven bone formed in the control ungrafted sockets at the same time point were 31%±14% and 24.1%±9.4%, respectively. Histochemical and immunohistochemical analyses showed dense mineralized bundles of type I collagen with high osteopontin expression intensity in the grafted sockets. The newly formed bone was well vascularized, with numerous active osteoblasts, Haversian systems, and osteocytes indicating maturation. In contrast, the new bone in the control ungrafted sockets was immature, rich in type III collagen, and had a low osteocyte density. Conclusions: The resorption of SCPC granules in 6 months was coordinated with better new bone formation than was observed in untreated sockets. SCPC is a resorbable bone graft material that enhances bone formation and maturation through its stimulatory effect on bone cell function.

• Journal of Veterinary Clinics
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• v.40 no.1
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• pp.16-24
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• 2023

This study aimed to compare complete ruptured tendon healing between two different repair methods using the Achilles tendon of New Zealand white rabbits. Thoracolumbar fascia (TF) padded Kessler suture, polypropylene mesh (PM) padded Kessler suture, and Kessler suture only were performed on the completely transected lateral gastrocnemius tendon, and biomechanical and histologic characteristics were assessed after 8 weeks. For biomechanical assessment, the tensile strength of each repaired tendon was measured according to the established methods. For histomorphometric analysis, hematoxylin and eosin staining for general histology, and Masson's trichrome (MT) staining for collagen fibers, Alcian blue (AB) staining for proteoglycans were performed and analyzed. Significant increases in tensile strength with remarkable decreases in the abnormalities against nuclear roundness, cell density, fiber structure, and fiber alignment and significant decreases in the mean number of infiltrated inflammatory cells and AB-positive proteoglycan-occupied regions with increases in MT-positive collagen fiber-occupied regions were demonstrated in the Kessler suture with PM or TF padding groups as compared to those of the Kessler suture group. Both of PM and TF provided potent tensile strength and supported healing with the evidence of histological examinations. This means that augmentation with PM is useful for repairing a completely ruptured Achilles tendon, without additional surgery for autograft material harvesting.

• Journal of Korean Dental Science
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• v.16 no.2
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• pp.172-181
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• 2023

Purpose: To investigate the effect of epidermal growth factor (EGF) with collagen matrix (CM) for increasing gingival thickness. Materials and Methods: In five mongrel dogs, bilateral gingival defects were surgically made on the maxillary canines. After two months, either a subepithelial connective tissue graft (group SCTG) or CM with EGF (0.1 ug/ml, group EGF) was grafted, and the flap was coronally positioned to cover the graft materials. The animals were sacrificed after three months. Intraoral scanning was performed for soft tissue analysis. Histologic and histomorphometric analyses were performed. Result: Two animals exhibited wound dehiscence during the healing phase, leaving three for analysis. No statistically significant difference was found in soft tissue changes (P>0.05). The level of gingival margin (GM) increased in both groups (1.02±0.74 mm in group SCTG vs. 1.24±0.83 mm in group EGF). Linear increases at the GM pre-augmentation in the soft tissue profile were 1.08±0.58 mm in group SCTG and 0.96±0.73 mm in group EGF. Histomorphometric parameters (keratinized tissue height, tissue thickness, and rete peg density) were not significantly different between the groups (P>0.05). Conclusion: EGF loaded onto CM led to comparable gingival phenotype enhancement to SCTG.

• Journal of Korean Dental Science
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• v.17 no.2
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• pp.53-63
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• 2024

Purpose: To investigate the effects of simultaneous soft and hard tissue augmentation and the addition of polydeoxyribonucleotide (PDRN) on regenerative outcomes. Materials and Methods: In five mongrel dogs, chronic ridge defects were established in both mandibles. Six implants were placed in the mandible, producing buccal dehiscence defects. The implants were randomly allocated to one of the following groups: 1) control: no treatment; 2) GBR: guided bone regeneration (GBR) only; 3) GBR/PDRN: GBR+PDRN application to bone substitute particles; 4) GBR/CTG: GBR+connective tissue grafting (CTG); 5) GBR/VCMX: GBR+soft tissue augmentation using volume stable collagen matrix (VCMX); and 6) group GBR/VCMX/PDRN: GBR+VCMX soaked with PDRN. The healing abutments were connected to the implants to provide additional room for tissue regeneration. Submerged healing was achieved. The animals were euthanized after four months. Histological and histomorphometric analyses were then performed. Results: Healing abutments were gradually exposed during the healing period. Histologically, minimal new bone formation was observed in the dehiscence defects. No specific differences were found between the groups regarding collagen fiber orientation and density in the augmented area. No traces of CTG or VCMX were detected. Histomorphometrically, the mean tissue thickness was greater in the control group than in the other groups above the implant shoulder (IS). Below the IS level, the CTG and PDRN groups exhibited more favorable tissue thickness than the other groups. Conclusion: Failure of submerged healing after tissue augmentation deteriorated the tissue contour. PDRN appears to have a positive effect on soft tissues.

• Journal of Periodontal and Implant Science
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• v.53 no.6
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• pp.417-428
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• 2023

Purpose: To investigate the effect of xenogeneic collagen matrix (XCM) with polydeoxyribonucleotide (PDRN) for gingival phenotype modification compared to autogenous connective tissue graft. Methods: Five mongrel dogs were used in this study. Box-type gingival defects were surgically created bilaterally on the maxillary canines 8 weeks before gingival augmentation. A coronally positioned flap was performed with either a subepithelial connective tissue graft (SCTG) or XCM with PDRN (2.0 mg/mL). The animals were sacrificed after 12 weeks. Intraoral scanning was performed for soft tissue analysis, and histologic and histomorphometric analyses were performed. Results: One animal exhibited wound dehiscence, leaving 4 for analysis. Superimposition of STL files revealed no significant difference in the amount of gingival thickness increase (ranging from 0.69±0.25 mm to 0.80±0.31 mm in group SCTG and from 0.48±0.25 mm to 0.85±0.44 mm in group PDRN; P>0.05). Histomorphometric analysis showed no significant differences between the groups in supracrestal gingival tissue height, keratinized tissue height, tissue thickness, and rete peg density (P>0.05). Conclusions: XCM soaked with PDRN yielded comparable gingival augmentation to SCTG.

• Journal of Nutrition and Health
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• v.41 no.3
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• pp.206-215
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• 2008

The purpose of this study was to investigate the effect of manganese (Mn) supplementation on bone status and calcium balance in ovariectomized rats according to the calcium intake levels. Total of 50 Sprague Dawley female rats (6 weeks) were divided into 5 groups and bred for 12 weeks: sham operated control group (SACa), OVX Ca deficiency group (OLCa) with Ca deficiency diet (0.1% Ca modified AIN-93N diet), OVX Ca deficiency & Mn supplement group (OLCaMn), OVX adequate Ca group (OACa; 0.5% Ca AIN-93N diet) and OVX adequate Ca & Mn supplement group (OACaMn). BMD (bone mineral density) of the femur was increased by Mn supplementation in OVX adequate Ca group. However, BMDs of spine, femur and tibia were lowered in OLCa compared to the OLCaMn group. Bone strength of tibia in OLCaMn group was significantly lower than OLCa group. Serum ALP (alkaline phosphatase) and CTx (C-telopeptide of collagen cross-links) levels were significantly higher in ovariectomized rats than those in the sham group, but they were not changed by Mn supplementation. Ca retention rate and Ca absorption rate did not differ among the experimental groups. Urinary Ca excretion was increased by Mn supplementation in Ca deficiency rats. In summary, Mn supplementation resulted in positive effects on bone mineral density ovariectomized rats with which intake adequate Ca. However, Mn supplementation on Ca deficiency ovariectomized rats resulted in decrement of BMO and bone strength by increasing Ca excretion. Therefore, it is encouraged to consider calcium intake levels in supplementation of manganese in order to prevent postmenopausal osteoporosis and to keep bone healthy. (KoreanJNutr2008; 41(3): 206~215)