Ui-Won Jung - Academia.edu (original) (raw)

Papers by Ui-Won Jung

Clinical oral implants research, Jan 6, 2017

Improvement in localized bone regeneration is needed to avoid the use of autogenous tissue. For t... more Improvement in localized bone regeneration is needed to avoid the use of autogenous tissue. For that purpose, the use biologic mediators was proposed. The aim was to test whether or not one of two biologic mediators, recombinant human bone morphogenetic protein-2 (rhBMP-2) or recombinant platelet-derived growth factor (rhPDGF-BB), is superior to the other and to control groups for localized bone regeneration. Four cylinders (height: 5 mm; diameter: 7 mm) were screwed on the parietal and frontal bones at the cranium in 12 rabbits. The cylinders either received (i) deproteinized bovine bone mineral (DBBM) mixed rhBMP-2 (DBBM/BMP-2), (ii) DBBM mixed with rhPDGF-BB (DBBM/PDGF), (iii) DBBM (DBBM), and (iv) empty control (control). Rabbits were euthanized at 2 and 8 weeks (n = 6, respectively). Conventional histomorphometric and micro-CT analyses were performed. Parametric linear mixed models were applied for the analyses with Bonferroni correction for the multiple group comparisons. The ...

Clinical Oral Implants Research, 2016

The objectives of this study were to evaluate bone regeneration beneath a newly devised bone subs... more The objectives of this study were to evaluate bone regeneration beneath a newly devised bone substitute combined with collagen membrane (called a bone patch) lying over a concomitantly placed mini-implant following sinus floor elevation and verify its usefulness as a carrier system for recombinant human bone morphogenetic protein-2 (rhBMP-2) in rabbits. The sinus floor elevation procedure was performed bilaterally in five rabbits. Either a plain bone patch (control group) or an rhBMP-2-loaded patch (experimental group) was randomly placed beneath the elevated sinus membrane (SM) of both sinuses, where the mini-implants were concomitantly placed. Micro-computed tomographic and histologic analyses were performed at 4 weeks post-surgery. In micro-computed tomography, the median values of the total augmented volume and the mineralized bone volume were significantly higher in the experimental group than in the control group (161 vs. 122 mm(3) [P < 0.01] and 48 vs. 42 mm(3) [P < 0.05], respectively). Histometric analysis revealed the same outcomes, with new bone areas of 6.41 and 2.97 mm(2) in the experimental and control groups, respectively (P < 0.001), and bone-to-implant contact ratios of 22.6% and 5.2%, respectively (P < 0.001). The newly devised bone patch in this study can support the elevated SM and facilitate bone regeneration from the basal bone with a reduced amount of biomaterial. The addition of rhBMP-2 may shorten the healing time for multidirectional bone regeneration toward the implant.

Journal of biomedical materials research. Part B, Applied biomaterials, Jan 10, 2016

Histone deacetylase inhibitors such as sodium butyrate (SB) have been suggested to be promising c... more Histone deacetylase inhibitors such as sodium butyrate (SB) have been suggested to be promising candidate small molecules for bone regeneration. In this study, the capacity of SB loaded onto calcium sulfate (CaS) to enhance bone formation was investigated in a rabbit sinus model. Following preparation of the sinus access window on a randomly selected side, SB loaded onto CaS (CaS/SB) was grafted in five rabbits, and CaS alone (control) was grafted in another five rabbits. The animals were euthanized after 4 weeks for radiographic, histometric, and immunohistochemical analyses. There was a statistically significant difference in the total augmented volume between the groups in the radiographic analysis (158.22 ± 39.31 mm(3) and 107.09 ± 39.69 mm(3) , respectively, p = 0.040). The CaS/SB group showed a larger portion of mature lamellar bone and a higher level of mineralization of bone trabeculae, characterized by more intense labeling with osteocalcin compared with the control group i...

Clinical oral implants research, Jan 9, 2016

The aim of this study was to evaluate the hybrid technique, which was modified from the lateral a... more The aim of this study was to evaluate the hybrid technique, which was modified from the lateral approach in sinus elevation by combining transalveolar access. Sixty patients (mean age of 53.3 ± 11.6 years) with 105 implants placed in the posterior maxilla with the average remaining bone height (RBH) of 4.3 ± 1.8 mm (range of 1.2-9.2 mm) were enrolled in the hybrid group and followed up for 96 months. The control group included 36 patients with 44 implants placed in the corresponding site with sufficient RBH. Cumulative survival rate (CSR), radiographic measurements in RBH, augmented bone height (ABH), and marginal bone loss (MBL) were analyzed during the follow-up period. Cumulative survival rate in the hybrid group was 98.1%, which was comparable to the control group (97.7%). MBL of the mesial and distal aspects in the hybrid group (0.28 ± 0.66 mm and 0.41 ± 0.93 mm, respectively) was comparable to the control group (0.84 ± 1.11 mm and 0.76 ± 0.88 mm, respectively). In the hybrid g...

Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons, Jan 18, 2016

This study evaluated a commercially available, 3-dimensional gel-type polyethylene glycol (PEG) m... more This study evaluated a commercially available, 3-dimensional gel-type polyethylene glycol (PEG) membrane as a carrier for recombinant human bone morphogenetic protein-2 (rhBMP-2) using a rat calvarial defect model. Another gel-type carrier, fibrin-fibronectin system (FFS), was used as a positive control. Critical-size defects were made in the rat calvarium, which were allocated to 1 of 10 groups comprising 2 healing periods and biomaterial conditions: 1) sham control, 2) FFS only, 3) FFS plus BMP-2, 4) PEG only, and 5) PEG plus BMP-2. Radiographic and histologic analyses were performed at 2 and 8 weeks after surgery. After 2 weeks, some parts of the FFS were biodegraded and extensive cellular infiltration was observed at sites that received FFS or FFS plus BMP-2. The PEG membrane retained its augmented volume without cellular infiltration at sites that received PEG or PEG plus BMP-2. After 8 weeks, the FFS was completely degraded and replaced by new bone and connective tissues. In c...

Clinical oral implants research, Jan 20, 2016

The aim of the study was to test whether or not the use of a polyethylene glycol (PEG) hydrogel w... more The aim of the study was to test whether or not the use of a polyethylene glycol (PEG) hydrogel with or without the addition of an arginylglycylaspartic acid (RGD) sequence applied as a matrix in combination with hydroxyapatite/tricalciumphosphate (HA/TCP) results in similar peri-implant bone regeneration as traditional guided bone regeneration procedures. In 12 beagle dogs, implant placement and peri-implant bone regeneration were performed 2 months after tooth extraction in the maxilla. Two standardized box-shaped defects were bilaterally created, and dental implants were placed in the center of the defects with a dehiscence of 4 mm. Four treatment modalities were randomly applied: i)HA/TCP mixed with a synthetic PEG hydrogel, ii)HA/TCP mixed with a synthetic PEG hydrogel supplemented with an RGD sequence, iii)HA/TCP covered with a native collagen membrane (CM), iv)and no bone augmentation (empty). After a healing period of 8 or 16 weeks, micro-CT and histological analyses were pe...

Clinical Oral Implants Research, 2016

The aim of this retrospective study was to determine the clinical and the radiographic outcomes o... more The aim of this retrospective study was to determine the clinical and the radiographic outcomes of dental implants placed in elderly people older than 65 years. In total, 902 implants in 346 patients (age: 65-89 years) were followed up for 2-17 years following the implant surgery. The survival rate of these implants was recorded and analyzed. Changes in marginal bone levels were also analyzed in serial radiographs, and Cox regression analysis for implant loss was performed. The survival rates were 95.39% and 99.98% in the implant- and patient-based analyses, respectively (involving a total of 29 implant failures), and the marginal bone loss at the implants was 0.17 ± 0.71 mm (mean ± SD). The number of failures was greatest in patients aged 65-69 years. The Cox regression with shared frailty analysis showed that implant loss was significantly greater in those aged 65-69 years than in those aged 70-74 years (P < 0.05), and it varied between specific implant systems. Within the limitations of this retrospective study, it was concluded that implant therapy can be successfully provided to elderly patients and that age alone does not seem to affect the implant survival rate.

Clinical oral implants research, Jan 8, 2016

The aim of this study was to observe the sequential healing of onlay grafts in terms of the volum... more The aim of this study was to observe the sequential healing of onlay grafts in terms of the volumetric and histologic changes using different bone substances and absorbable membranes according to the presence of collagen cross-linking. Four groups involving onlay grafting with different materials were randomly assigned to both sides of the maxillae of 15 beagle dogs: (i) control group without any treatment; (ii) group NN, bovine hydroxyapatite incorporated into a non-cross-linked collagen matrix (BHC) + non-cross-linked collagen membrane (NCCM); (iii) group NC, BHC + cross-linked collagen membrane (CCM); and (iv) group CC, porcine hydroxyapatite incorporated into a cross-linked collagen matrix + CCM. Radiographic and histological analyses were performed after three different healing periods: 4, 8 and 12 weeks. At week 4, the bone substances were well localized under the barrier membrane in groups NC and CC, while the bone substances became spread out and flattened in group NN. Simil...

The Anatomical Record, 2015

This study evaluated the prevalence of cervical enamel projections (CEPs) in mandibular molars, a... more This study evaluated the prevalence of cervical enamel projections (CEPs) in mandibular molars, and analyzed the correlation between CEPs and furcation involvement (FI) based on cone-beam computed tomography (CBCT) data in a Korean population. CBCT images obtained from March 2012 to August 2012 were analyzed. CEPs and FI on the buccal and lingual surface were classified in three-dimensionally reconstructed images and cross-sectional views, and the correlation between these two parameters was analyzed. In total, 982 teeth in 425 patients were analyzed. The overall prevalence rate of CEPs was 76% (71% and 27% on the buccal and lingual surfaces, respectively). Grade I CEPs were the most common, followed by CEPs of grades II and III. There was a statistically significant, but negligible correlation between the CEP grade and the degree of FI on the buccal and lingual surfaces. Within the limitations of this cross-sectional study, a high prevalence of CEPs were found in a Korean population, but the role of CEPs in provoking FI appeared not to be decisive. This article is protected by copyright. All rights reserved.

Journal of periodontal & implant science, 2015

The aim of this study was to determine the effect of overlaying titanium mesh (TM) with an adjunc... more The aim of this study was to determine the effect of overlaying titanium mesh (TM) with an adjunctive collagen membrane (CM) for preserving the buccal bone when used in association with immediate implant placement in dogs. Immediate implant placements were performed in the mesial sockets of the third premolars of five dogs. At one site the TM was attached to the fixture with the aid of its own stabilizers and then covered by a CM (CM group), while the contralateral site received only TM (TM group). Biopsy specimens were retrieved for histologic and histomorphometric analyses after 16 weeks. All samples exhibited pronounced buccal bone resorption, and a high rate of TM exposure was noted (in three and four cases of the five samples in each of the TM and CM groups, respectively). A dense fibrous tissue with little vascularity or cellularity had infiltrated through the pores of the TM irrespective of the presence of a CM. The distances between the fixture platform and the first bone-im...

The Journal of the Korean Academy of Periodontology, 2008

Purpose: The purpose of this study was to evaluate 2 years cumulative survival rate of implants o... more Purpose: The purpose of this study was to evaluate 2 years cumulative survival rate of implants on augmented sinus area using MBCP, mixture of MBCP and ICB, and mixture of MBCP and autogenous bone by means of clinical and radiologic methods. Materials and Methods: In a total of 37 patients, 41 maxillary sinuses were augmented and 89 implant fixtures were installed simultaneously or after a regular healing period. The patients were divided in 3 groups: MBCP only, MBCP combined with ICB, MBCP combined with autogenous bone. After delivery of prosthesis, along 2 years of observation period, all implants were evaluated clinically and radiologically. And the results were as follows.

Biomaterials research, 2015

In-vitro and animal studies using EDC cross-linked membranes have shown great resistance to enzym... more In-vitro and animal studies using EDC cross-linked membranes have shown great resistance to enzymatic digestion as well as low cytotoxicity, and indicated its potential expediency as a barrier membrane for guided bone regeneration (GBR). The purpose of this study was to evaluate the efficacy, biocompatibility and degradation kinetics of a novel 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)-cross-linked type I collagen membrane for regeneration of rabbit calvarial defects. EDC cross-linked type I collagen membrane and macroporous biphasic calcium phosphate (MBCP) consisting of 60 % hydroxyapatite and 40 % β-tricalcium phosphate were used in this study. Four circular defects (ø = 8 mm) were created in each calvarium of 12 male white rabbits. The experimental groups randomly allocated to the defects were as follows - (1) sham control, (2) EDC-cross-linked collagen membrane (EDC membrane), (3) bone graft (BG), and (4) bone graft with collagen membrane (B-EDC membrane). Specimens ...

Journal of Periodontal & Implant Science, 2015

The objective of this study was to comparatively assess the bone regenerative capacity of absorba... more The objective of this study was to comparatively assess the bone regenerative capacity of absorbable collagen sponge (ACS), biphasic calcium phosphate block (BCP) and collagenated biphasic calcium phosphate (CBCP) loaded with a low dose of recombinant human bone morphogenetic protein-2 (rhBMP-2). The CBCP was characterized by X-ray diffraction and scanning electron microscopy. In rabbit calvaria, four circular 8-mm-diameter defects were created and assigned to one of four groups: (1) blood-filled group (control), (2) rhBMP-2-soaked absorbable collagen sponge (0.05 mg/mL, 0.1 mL; CS group), (3) rhBMP-2-loaded BCP (BCP group), or (4) rhBMP-2-loaded CBCP (CBCP group). The animals were sacrificed either 2 weeks or 8 weeks postoperatively. Histological and histomorphometric analyses were performed. The CBCP showed web-like collagen fibrils on and between particles. Greater dimensional stability was observed in the BCP and CBCP groups than in the control and the CS groups at 2 and 8 weeks. The new bone formation was significantly greater in the BCP and CBCP groups than in the control and CS groups at 2 weeks, but did not significantly differ among the four groups at 8 week. The CBCP group exhibited more new bone formation in the intergranular space and in the center of the defect compared to the BCP group at 2 weeks, but a similar histologic appearance was observed in both groups at 8 weeks. The dose of rhBMP-2 in the present study enhanced bone regeneration in the early healing period when loaded on BCP and CBCP in rabbit calvarial defects.

Biomaterials Research, 2015

Background: The aim of this study was to determine the osteoconductivity of biphasic calcium phos... more Background: The aim of this study was to determine the osteoconductivity of biphasic calcium phosphate collagen composite (BCPC) in rabbit calvarial defect model by comparing with biphasic calcium phosphate (BCP). Four 8 mm diameter bicortical calvarial defects were made in ten rabbits. Each of the defects was randomly assigned and filled with 1) collagen sponge, 2) BCP, 3) BCPC, and 4) nothing as control. The animals were sacrificed at either 2 weeks (n = 5) or 8 weeks (n = 5) healing period. Results: All groups showed wedge shaped new bone formation limited to the area of the defect margin at both healing periods. The amounts of new bone and defect closure were similar among all groups. In the control and collagen sponge group, the center of the defect was depressed by surrounding tissues. In contrast, in BCP and BCPC group, the center of the defect did not depressed and the grafted materials maintained the space. And the augmented area was significantly higher in BCP and BCPC group compared to the control and collagen sponge group at both healing periods (p < 0.05).

Biomaterials Research, 2015

The aim of this study was to determine the osteoconductivity of hydroxyapatite particles (HAP) as... more The aim of this study was to determine the osteoconductivity of hydroxyapatite particles (HAP) as a carrier for Escherichia coli-derived recombinant human bone morphogenetic protein-2 (ErhBMP-2). Two 8-mm diameter bicortical calvarial defects were created in each of 20 rabbits. One of each pair of defects was randomly assigned to be filled with HAP only (HAP group) or ErhBMP-2 loaded HAP (ErhBMP-2/HAP group), while the other defect was left untreated (control group). The animals were killed after either 2 weeks (n = 10) or 8 weeks (n = 10) of healing, and histological, histomorphometric, and tomographic analyses were performed. All experimental sites showed uneventful healing during the postoperative healing period. In both histomorphometric and tomographic analyses, the new bone area or volume of the ErhBMP-2/HAP group was significantly greater than that of the HAP and control groups at 2 weeks (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05). However, at 8 weeks, no significant difference in new bone area or volume was observed between the ErhBMP-2/HAP and HAP groups. The total augmented area or volume was not significantly different between the ErhBMP-2/HAP and HAP groups at 2 and 8 weeks. Combining ErhBMP-2 with HAP could significantly promote rapid initial new bone formation. Moreover, HAP graft could increase new bone formation and space maintenance, therefore it might be one of the effective carriers of ErhBMP-2.

Objective: The aim of this study was to investigate the effect of dental pulp stem cells (DPSCs) ... more Objective: The aim of this study was to investigate the effect of dental pulp stem cells (DPSCs) and periodontal ligament stem cells (PDLSCs) on one-wall periodontal intrabony defect, when seeded onto different 3-dimensional (3D) scaffold materials: nano-Hydroxyapatite (nHA)-coated silk scaffolds. Method: For this study, 5 dogs were used. Four of the defects in each animal were separately and randomly assigned with following groups: The PDLSC-cultured scaffold transplantation group (PDLSC group), the DPSC-cultured scaffold transplantation group (DPSC group), the normal saline-soaked scaffold transplantation group (NCTL group), and the control group. The animals were sacrificed at 8 weeks postsurgery. Result: SEM observation of the surface of the silk scaffold showed the combination of porous spongy morphology and lamellar structures. After the cell-seeding procedure, cells attached and spread well on the surfaces of scaffolds. In histologic analysis, the aspect of the formed tissues...

Journal of periodontal & implant science, 2015

The purpose of this animal study was to perform a histological and histomorphometric analysis in ... more The purpose of this animal study was to perform a histological and histomorphometric analysis in order to elucidate the effect of fibroblast growth factor-2 (FGF-2) on injured periodontal ligament (PDL) and cementum after tooth replantation in dogs. The roots of 36 mandibular premolars from six mongrel dogs were used in this study. The roots were randomly divided into three groups: (1) a positive control group (n=12), in which the PDL was retained; (2) a negative control group (n=12), in which the PDL and the cementum between the notches were removed; and (3) an experimental group (n=12), in which the PDL and the cementum between the notches were removed and the roots were soaked in an FGF-2 solution (30 µg/0.1 mL). After treating the root surfaces, the extracted roots were replanted into extraction sockets. The animals were sacrificed four and eight weeks after surgery for histologic and histomorphometric evaluation. At four and eight weeks, normal PDLs covered the roots in the pos...

Clinical oral implants research, Jan 24, 2015

This study compared the efficacies of different layered approaches using autogenous bone and synt... more This study compared the efficacies of different layered approaches using autogenous bone and synthetic bone substitute for ridge augmentation on implant dehiscence defects in dogs. Right mandibular second, third, and fourth premolars and the first molar were extracted, followed by standardized one-wall defect preparation in five dogs. After a healing period of 12 weeks, three implants (Implantium(®) ) were installed. Each of the three implant dehiscence defects was grafted with a different material as follows: (i) synthetic bone substitute combined with collagen (SBC; SBC group), (ii) inner autogenous bone layer and outer SBC layer (IAB group), and (iii) inner SBC layer and outer autogenous bone layer (OAB group). The grafted sites were covered with a resorbable collagen membrane. Quantitative and qualitative analyses of the subsequent bone regeneration were performed at 12 weeks postoperatively. The dome-like augmented shape was relatively well maintained in the IAB and OAB groups,...

Journal of biomedical materials research. Part B, Applied biomaterials, Jan 18, 2015

This study aimed to determine healing patterns in periimplant gap defect grafted with demineraliz... more This study aimed to determine healing patterns in periimplant gap defect grafted with demineralized bovine bone mineral (DBBM) and porous titanium granules (PTG), which are known to induce a minimal tissue reaction and to undergo minimal biodegradation in healing process. Experiments were performed using a standardized periimplant gap-defect model in dogs with two observational periods: 4 and 8 weeks. Circumferential defects were surgically induced around dental implants on unilateral mandibles in five dogs, and collagen barrier membranes were placed over the DBBM and PTG grafts at two experimental sites and over a nongrafted site. Four weeks later, the same procedures were performed on the contralateral mandible, and the animals allowed to heal for a further 4 weeks, after which they were sacrificed and their mandibles with graft/control sites harvested for histologic evaluation. Both types of grafted biomaterials significantly enhanced the defect fill with newly formed bone, but t...

The Journal of the Korean Academy of Periodontology, 2008

... Dogs were placed on a heating pad, in-tubated, administered 2% enflurane, and monitored with ... more ... Dogs were placed on a heating pad, in-tubated, administered 2% enflurane, and monitored with an electrocardiogram. After disinfecting the sur-gical site, 2% lidocaine HCl with epinephrine 1:100,000 (Kwangmyung Pharm., Seoul, Korea) was administered by infiltration. ...

Clinical oral implants research, Jan 6, 2017

Improvement in localized bone regeneration is needed to avoid the use of autogenous tissue. For t... more Improvement in localized bone regeneration is needed to avoid the use of autogenous tissue. For that purpose, the use biologic mediators was proposed. The aim was to test whether or not one of two biologic mediators, recombinant human bone morphogenetic protein-2 (rhBMP-2) or recombinant platelet-derived growth factor (rhPDGF-BB), is superior to the other and to control groups for localized bone regeneration. Four cylinders (height: 5 mm; diameter: 7 mm) were screwed on the parietal and frontal bones at the cranium in 12 rabbits. The cylinders either received (i) deproteinized bovine bone mineral (DBBM) mixed rhBMP-2 (DBBM/BMP-2), (ii) DBBM mixed with rhPDGF-BB (DBBM/PDGF), (iii) DBBM (DBBM), and (iv) empty control (control). Rabbits were euthanized at 2 and 8 weeks (n = 6, respectively). Conventional histomorphometric and micro-CT analyses were performed. Parametric linear mixed models were applied for the analyses with Bonferroni correction for the multiple group comparisons. The ...

Clinical Oral Implants Research, 2016

The objectives of this study were to evaluate bone regeneration beneath a newly devised bone subs... more The objectives of this study were to evaluate bone regeneration beneath a newly devised bone substitute combined with collagen membrane (called a bone patch) lying over a concomitantly placed mini-implant following sinus floor elevation and verify its usefulness as a carrier system for recombinant human bone morphogenetic protein-2 (rhBMP-2) in rabbits. The sinus floor elevation procedure was performed bilaterally in five rabbits. Either a plain bone patch (control group) or an rhBMP-2-loaded patch (experimental group) was randomly placed beneath the elevated sinus membrane (SM) of both sinuses, where the mini-implants were concomitantly placed. Micro-computed tomographic and histologic analyses were performed at 4 weeks post-surgery. In micro-computed tomography, the median values of the total augmented volume and the mineralized bone volume were significantly higher in the experimental group than in the control group (161 vs. 122 mm(3) [P &amp;amp;amp;amp;lt; 0.01] and 48 vs. 42 mm(3) [P &amp;amp;amp;amp;lt; 0.05], respectively). Histometric analysis revealed the same outcomes, with new bone areas of 6.41 and 2.97 mm(2) in the experimental and control groups, respectively (P &amp;amp;amp;amp;lt; 0.001), and bone-to-implant contact ratios of 22.6% and 5.2%, respectively (P &amp;amp;amp;amp;lt; 0.001). The newly devised bone patch in this study can support the elevated SM and facilitate bone regeneration from the basal bone with a reduced amount of biomaterial. The addition of rhBMP-2 may shorten the healing time for multidirectional bone regeneration toward the implant.

Journal of biomedical materials research. Part B, Applied biomaterials, Jan 10, 2016

Histone deacetylase inhibitors such as sodium butyrate (SB) have been suggested to be promising c... more Histone deacetylase inhibitors such as sodium butyrate (SB) have been suggested to be promising candidate small molecules for bone regeneration. In this study, the capacity of SB loaded onto calcium sulfate (CaS) to enhance bone formation was investigated in a rabbit sinus model. Following preparation of the sinus access window on a randomly selected side, SB loaded onto CaS (CaS/SB) was grafted in five rabbits, and CaS alone (control) was grafted in another five rabbits. The animals were euthanized after 4 weeks for radiographic, histometric, and immunohistochemical analyses. There was a statistically significant difference in the total augmented volume between the groups in the radiographic analysis (158.22 ± 39.31 mm(3) and 107.09 ± 39.69 mm(3) , respectively, p = 0.040). The CaS/SB group showed a larger portion of mature lamellar bone and a higher level of mineralization of bone trabeculae, characterized by more intense labeling with osteocalcin compared with the control group i...

Clinical oral implants research, Jan 9, 2016

The aim of this study was to evaluate the hybrid technique, which was modified from the lateral a... more The aim of this study was to evaluate the hybrid technique, which was modified from the lateral approach in sinus elevation by combining transalveolar access. Sixty patients (mean age of 53.3 ± 11.6 years) with 105 implants placed in the posterior maxilla with the average remaining bone height (RBH) of 4.3 ± 1.8 mm (range of 1.2-9.2 mm) were enrolled in the hybrid group and followed up for 96 months. The control group included 36 patients with 44 implants placed in the corresponding site with sufficient RBH. Cumulative survival rate (CSR), radiographic measurements in RBH, augmented bone height (ABH), and marginal bone loss (MBL) were analyzed during the follow-up period. Cumulative survival rate in the hybrid group was 98.1%, which was comparable to the control group (97.7%). MBL of the mesial and distal aspects in the hybrid group (0.28 ± 0.66 mm and 0.41 ± 0.93 mm, respectively) was comparable to the control group (0.84 ± 1.11 mm and 0.76 ± 0.88 mm, respectively). In the hybrid g...

Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons, Jan 18, 2016

This study evaluated a commercially available, 3-dimensional gel-type polyethylene glycol (PEG) m... more This study evaluated a commercially available, 3-dimensional gel-type polyethylene glycol (PEG) membrane as a carrier for recombinant human bone morphogenetic protein-2 (rhBMP-2) using a rat calvarial defect model. Another gel-type carrier, fibrin-fibronectin system (FFS), was used as a positive control. Critical-size defects were made in the rat calvarium, which were allocated to 1 of 10 groups comprising 2 healing periods and biomaterial conditions: 1) sham control, 2) FFS only, 3) FFS plus BMP-2, 4) PEG only, and 5) PEG plus BMP-2. Radiographic and histologic analyses were performed at 2 and 8 weeks after surgery. After 2 weeks, some parts of the FFS were biodegraded and extensive cellular infiltration was observed at sites that received FFS or FFS plus BMP-2. The PEG membrane retained its augmented volume without cellular infiltration at sites that received PEG or PEG plus BMP-2. After 8 weeks, the FFS was completely degraded and replaced by new bone and connective tissues. In c...

Clinical oral implants research, Jan 20, 2016

The aim of the study was to test whether or not the use of a polyethylene glycol (PEG) hydrogel w... more The aim of the study was to test whether or not the use of a polyethylene glycol (PEG) hydrogel with or without the addition of an arginylglycylaspartic acid (RGD) sequence applied as a matrix in combination with hydroxyapatite/tricalciumphosphate (HA/TCP) results in similar peri-implant bone regeneration as traditional guided bone regeneration procedures. In 12 beagle dogs, implant placement and peri-implant bone regeneration were performed 2 months after tooth extraction in the maxilla. Two standardized box-shaped defects were bilaterally created, and dental implants were placed in the center of the defects with a dehiscence of 4 mm. Four treatment modalities were randomly applied: i)HA/TCP mixed with a synthetic PEG hydrogel, ii)HA/TCP mixed with a synthetic PEG hydrogel supplemented with an RGD sequence, iii)HA/TCP covered with a native collagen membrane (CM), iv)and no bone augmentation (empty). After a healing period of 8 or 16 weeks, micro-CT and histological analyses were pe...

Clinical Oral Implants Research, 2016

The aim of this retrospective study was to determine the clinical and the radiographic outcomes o... more The aim of this retrospective study was to determine the clinical and the radiographic outcomes of dental implants placed in elderly people older than 65 years. In total, 902 implants in 346 patients (age: 65-89 years) were followed up for 2-17 years following the implant surgery. The survival rate of these implants was recorded and analyzed. Changes in marginal bone levels were also analyzed in serial radiographs, and Cox regression analysis for implant loss was performed. The survival rates were 95.39% and 99.98% in the implant- and patient-based analyses, respectively (involving a total of 29 implant failures), and the marginal bone loss at the implants was 0.17 ± 0.71 mm (mean ± SD). The number of failures was greatest in patients aged 65-69 years. The Cox regression with shared frailty analysis showed that implant loss was significantly greater in those aged 65-69 years than in those aged 70-74 years (P &amp;amp;amp;amp;lt; 0.05), and it varied between specific implant systems. Within the limitations of this retrospective study, it was concluded that implant therapy can be successfully provided to elderly patients and that age alone does not seem to affect the implant survival rate.

Clinical oral implants research, Jan 8, 2016

The aim of this study was to observe the sequential healing of onlay grafts in terms of the volum... more The aim of this study was to observe the sequential healing of onlay grafts in terms of the volumetric and histologic changes using different bone substances and absorbable membranes according to the presence of collagen cross-linking. Four groups involving onlay grafting with different materials were randomly assigned to both sides of the maxillae of 15 beagle dogs: (i) control group without any treatment; (ii) group NN, bovine hydroxyapatite incorporated into a non-cross-linked collagen matrix (BHC) + non-cross-linked collagen membrane (NCCM); (iii) group NC, BHC + cross-linked collagen membrane (CCM); and (iv) group CC, porcine hydroxyapatite incorporated into a cross-linked collagen matrix + CCM. Radiographic and histological analyses were performed after three different healing periods: 4, 8 and 12 weeks. At week 4, the bone substances were well localized under the barrier membrane in groups NC and CC, while the bone substances became spread out and flattened in group NN. Simil...

The Anatomical Record, 2015

This study evaluated the prevalence of cervical enamel projections (CEPs) in mandibular molars, a... more This study evaluated the prevalence of cervical enamel projections (CEPs) in mandibular molars, and analyzed the correlation between CEPs and furcation involvement (FI) based on cone-beam computed tomography (CBCT) data in a Korean population. CBCT images obtained from March 2012 to August 2012 were analyzed. CEPs and FI on the buccal and lingual surface were classified in three-dimensionally reconstructed images and cross-sectional views, and the correlation between these two parameters was analyzed. In total, 982 teeth in 425 patients were analyzed. The overall prevalence rate of CEPs was 76% (71% and 27% on the buccal and lingual surfaces, respectively). Grade I CEPs were the most common, followed by CEPs of grades II and III. There was a statistically significant, but negligible correlation between the CEP grade and the degree of FI on the buccal and lingual surfaces. Within the limitations of this cross-sectional study, a high prevalence of CEPs were found in a Korean population, but the role of CEPs in provoking FI appeared not to be decisive. This article is protected by copyright. All rights reserved.

Journal of periodontal & implant science, 2015

The aim of this study was to determine the effect of overlaying titanium mesh (TM) with an adjunc... more The aim of this study was to determine the effect of overlaying titanium mesh (TM) with an adjunctive collagen membrane (CM) for preserving the buccal bone when used in association with immediate implant placement in dogs. Immediate implant placements were performed in the mesial sockets of the third premolars of five dogs. At one site the TM was attached to the fixture with the aid of its own stabilizers and then covered by a CM (CM group), while the contralateral site received only TM (TM group). Biopsy specimens were retrieved for histologic and histomorphometric analyses after 16 weeks. All samples exhibited pronounced buccal bone resorption, and a high rate of TM exposure was noted (in three and four cases of the five samples in each of the TM and CM groups, respectively). A dense fibrous tissue with little vascularity or cellularity had infiltrated through the pores of the TM irrespective of the presence of a CM. The distances between the fixture platform and the first bone-im...

The Journal of the Korean Academy of Periodontology, 2008

Purpose: The purpose of this study was to evaluate 2 years cumulative survival rate of implants o... more Purpose: The purpose of this study was to evaluate 2 years cumulative survival rate of implants on augmented sinus area using MBCP, mixture of MBCP and ICB, and mixture of MBCP and autogenous bone by means of clinical and radiologic methods. Materials and Methods: In a total of 37 patients, 41 maxillary sinuses were augmented and 89 implant fixtures were installed simultaneously or after a regular healing period. The patients were divided in 3 groups: MBCP only, MBCP combined with ICB, MBCP combined with autogenous bone. After delivery of prosthesis, along 2 years of observation period, all implants were evaluated clinically and radiologically. And the results were as follows.

Biomaterials research, 2015

In-vitro and animal studies using EDC cross-linked membranes have shown great resistance to enzym... more In-vitro and animal studies using EDC cross-linked membranes have shown great resistance to enzymatic digestion as well as low cytotoxicity, and indicated its potential expediency as a barrier membrane for guided bone regeneration (GBR). The purpose of this study was to evaluate the efficacy, biocompatibility and degradation kinetics of a novel 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)-cross-linked type I collagen membrane for regeneration of rabbit calvarial defects. EDC cross-linked type I collagen membrane and macroporous biphasic calcium phosphate (MBCP) consisting of 60 % hydroxyapatite and 40 % β-tricalcium phosphate were used in this study. Four circular defects (ø = 8 mm) were created in each calvarium of 12 male white rabbits. The experimental groups randomly allocated to the defects were as follows - (1) sham control, (2) EDC-cross-linked collagen membrane (EDC membrane), (3) bone graft (BG), and (4) bone graft with collagen membrane (B-EDC membrane). Specimens ...

Journal of Periodontal & Implant Science, 2015

The objective of this study was to comparatively assess the bone regenerative capacity of absorba... more The objective of this study was to comparatively assess the bone regenerative capacity of absorbable collagen sponge (ACS), biphasic calcium phosphate block (BCP) and collagenated biphasic calcium phosphate (CBCP) loaded with a low dose of recombinant human bone morphogenetic protein-2 (rhBMP-2). The CBCP was characterized by X-ray diffraction and scanning electron microscopy. In rabbit calvaria, four circular 8-mm-diameter defects were created and assigned to one of four groups: (1) blood-filled group (control), (2) rhBMP-2-soaked absorbable collagen sponge (0.05 mg/mL, 0.1 mL; CS group), (3) rhBMP-2-loaded BCP (BCP group), or (4) rhBMP-2-loaded CBCP (CBCP group). The animals were sacrificed either 2 weeks or 8 weeks postoperatively. Histological and histomorphometric analyses were performed. The CBCP showed web-like collagen fibrils on and between particles. Greater dimensional stability was observed in the BCP and CBCP groups than in the control and the CS groups at 2 and 8 weeks. The new bone formation was significantly greater in the BCP and CBCP groups than in the control and CS groups at 2 weeks, but did not significantly differ among the four groups at 8 week. The CBCP group exhibited more new bone formation in the intergranular space and in the center of the defect compared to the BCP group at 2 weeks, but a similar histologic appearance was observed in both groups at 8 weeks. The dose of rhBMP-2 in the present study enhanced bone regeneration in the early healing period when loaded on BCP and CBCP in rabbit calvarial defects.

Biomaterials Research, 2015

Background: The aim of this study was to determine the osteoconductivity of biphasic calcium phos... more Background: The aim of this study was to determine the osteoconductivity of biphasic calcium phosphate collagen composite (BCPC) in rabbit calvarial defect model by comparing with biphasic calcium phosphate (BCP). Four 8 mm diameter bicortical calvarial defects were made in ten rabbits. Each of the defects was randomly assigned and filled with 1) collagen sponge, 2) BCP, 3) BCPC, and 4) nothing as control. The animals were sacrificed at either 2 weeks (n = 5) or 8 weeks (n = 5) healing period. Results: All groups showed wedge shaped new bone formation limited to the area of the defect margin at both healing periods. The amounts of new bone and defect closure were similar among all groups. In the control and collagen sponge group, the center of the defect was depressed by surrounding tissues. In contrast, in BCP and BCPC group, the center of the defect did not depressed and the grafted materials maintained the space. And the augmented area was significantly higher in BCP and BCPC group compared to the control and collagen sponge group at both healing periods (p < 0.05).

Biomaterials Research, 2015

The aim of this study was to determine the osteoconductivity of hydroxyapatite particles (HAP) as... more The aim of this study was to determine the osteoconductivity of hydroxyapatite particles (HAP) as a carrier for Escherichia coli-derived recombinant human bone morphogenetic protein-2 (ErhBMP-2). Two 8-mm diameter bicortical calvarial defects were created in each of 20 rabbits. One of each pair of defects was randomly assigned to be filled with HAP only (HAP group) or ErhBMP-2 loaded HAP (ErhBMP-2/HAP group), while the other defect was left untreated (control group). The animals were killed after either 2 weeks (n = 10) or 8 weeks (n = 10) of healing, and histological, histomorphometric, and tomographic analyses were performed. All experimental sites showed uneventful healing during the postoperative healing period. In both histomorphometric and tomographic analyses, the new bone area or volume of the ErhBMP-2/HAP group was significantly greater than that of the HAP and control groups at 2 weeks (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05). However, at 8 weeks, no significant difference in new bone area or volume was observed between the ErhBMP-2/HAP and HAP groups. The total augmented area or volume was not significantly different between the ErhBMP-2/HAP and HAP groups at 2 and 8 weeks. Combining ErhBMP-2 with HAP could significantly promote rapid initial new bone formation. Moreover, HAP graft could increase new bone formation and space maintenance, therefore it might be one of the effective carriers of ErhBMP-2.

Objective: The aim of this study was to investigate the effect of dental pulp stem cells (DPSCs) ... more Objective: The aim of this study was to investigate the effect of dental pulp stem cells (DPSCs) and periodontal ligament stem cells (PDLSCs) on one-wall periodontal intrabony defect, when seeded onto different 3-dimensional (3D) scaffold materials: nano-Hydroxyapatite (nHA)-coated silk scaffolds. Method: For this study, 5 dogs were used. Four of the defects in each animal were separately and randomly assigned with following groups: The PDLSC-cultured scaffold transplantation group (PDLSC group), the DPSC-cultured scaffold transplantation group (DPSC group), the normal saline-soaked scaffold transplantation group (NCTL group), and the control group. The animals were sacrificed at 8 weeks postsurgery. Result: SEM observation of the surface of the silk scaffold showed the combination of porous spongy morphology and lamellar structures. After the cell-seeding procedure, cells attached and spread well on the surfaces of scaffolds. In histologic analysis, the aspect of the formed tissues...

Journal of periodontal & implant science, 2015

The purpose of this animal study was to perform a histological and histomorphometric analysis in ... more The purpose of this animal study was to perform a histological and histomorphometric analysis in order to elucidate the effect of fibroblast growth factor-2 (FGF-2) on injured periodontal ligament (PDL) and cementum after tooth replantation in dogs. The roots of 36 mandibular premolars from six mongrel dogs were used in this study. The roots were randomly divided into three groups: (1) a positive control group (n=12), in which the PDL was retained; (2) a negative control group (n=12), in which the PDL and the cementum between the notches were removed; and (3) an experimental group (n=12), in which the PDL and the cementum between the notches were removed and the roots were soaked in an FGF-2 solution (30 µg/0.1 mL). After treating the root surfaces, the extracted roots were replanted into extraction sockets. The animals were sacrificed four and eight weeks after surgery for histologic and histomorphometric evaluation. At four and eight weeks, normal PDLs covered the roots in the pos...

Clinical oral implants research, Jan 24, 2015

This study compared the efficacies of different layered approaches using autogenous bone and synt... more This study compared the efficacies of different layered approaches using autogenous bone and synthetic bone substitute for ridge augmentation on implant dehiscence defects in dogs. Right mandibular second, third, and fourth premolars and the first molar were extracted, followed by standardized one-wall defect preparation in five dogs. After a healing period of 12 weeks, three implants (Implantium(®) ) were installed. Each of the three implant dehiscence defects was grafted with a different material as follows: (i) synthetic bone substitute combined with collagen (SBC; SBC group), (ii) inner autogenous bone layer and outer SBC layer (IAB group), and (iii) inner SBC layer and outer autogenous bone layer (OAB group). The grafted sites were covered with a resorbable collagen membrane. Quantitative and qualitative analyses of the subsequent bone regeneration were performed at 12 weeks postoperatively. The dome-like augmented shape was relatively well maintained in the IAB and OAB groups,...

Journal of biomedical materials research. Part B, Applied biomaterials, Jan 18, 2015

This study aimed to determine healing patterns in periimplant gap defect grafted with demineraliz... more This study aimed to determine healing patterns in periimplant gap defect grafted with demineralized bovine bone mineral (DBBM) and porous titanium granules (PTG), which are known to induce a minimal tissue reaction and to undergo minimal biodegradation in healing process. Experiments were performed using a standardized periimplant gap-defect model in dogs with two observational periods: 4 and 8 weeks. Circumferential defects were surgically induced around dental implants on unilateral mandibles in five dogs, and collagen barrier membranes were placed over the DBBM and PTG grafts at two experimental sites and over a nongrafted site. Four weeks later, the same procedures were performed on the contralateral mandible, and the animals allowed to heal for a further 4 weeks, after which they were sacrificed and their mandibles with graft/control sites harvested for histologic evaluation. Both types of grafted biomaterials significantly enhanced the defect fill with newly formed bone, but t...

The Journal of the Korean Academy of Periodontology, 2008

... Dogs were placed on a heating pad, in-tubated, administered 2% enflurane, and monitored with ... more ... Dogs were placed on a heating pad, in-tubated, administered 2% enflurane, and monitored with an electrocardiogram. After disinfecting the sur-gical site, 2% lidocaine HCl with epinephrine 1:100,000 (Kwangmyung Pharm., Seoul, Korea) was administered by infiltration. ...