• Journal of Periodontal and Implant Science
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• 제53권6호
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• pp.429-443
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• 2023

Purpose: The aim of this study was to determine 1) the bone-regenerative effect of porcine bone block materials with or without collagen matrix incorporation, 2) the effect of a collagen barrier, and 3) the effect of adding recombinant human bone morphogenetic protein-2 (rhBMP-2) to the experimental groups. Methods: Four treatment modalities were applied to rabbit calvaria: 1) deproteinized bovine bone mineral blocks (DBBM), 2) porcine bone blocks with collagen matrix incorporation (PBC), 3) porcine bone blocks alone without collagen matrix incorporation (PB), and 4) PBC blocks covered by a collagen membrane (PBC+M). The experiments were repeated with the addition of rhBMP-2. The animals were sacrificed after either 2 or 12 weeks of healing. Micro-computed tomography (micro-CT), histologic, and histomorphometric analyses were performed. Results: Micro-CT indicated adequate volume stability in all block materials. Histologically, the addition of rhBMP-2 increased the amount of newly formed bone (NB) in all the blocks. At 2 weeks, minimal differences were noted among the NB of groups with or without rhBMP-2. At 12 weeks, the PBC+M group with rhBMP-2 presented the greatest NB (P<0.05 vs. the DBBM group with rhBMP-2), and the PBC and PB groups had greater NB than the DBBM group (P>0.05 without rhBMP-2, P<0.05 with rhBMP-2). Conclusions: The addition of rhBMP-2 enhanced NB formation in vertical augmentation using bone blocks, and a collagen barrier may augment the effect of rhBMP-2.

• Clinics in Shoulder and Elbow
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• 제26권3호
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• pp.287-295
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• 2023

Background: Posterolateral rotatory instability (PLRI) is a common mechanism of recurrent elbow instability. While the essential lesion is a deficiency in the lateral ulnar collateral ligament (LUCL), there are often associated concomitant bony lesions, such as an Osborne-Cotterill lesions (posterior capitellar fractures) and marginal radial head fractures, that compromise stability. Currently, there is no standard treatment for posterior capitellar deficiency associated with recurrent PLRI. Methods: We conducted a retrospective review of five patients with recurrent PLRI of the elbow associated with a posterior capitellar impaction fracture engaging with the radial head during normal range of motion. The patients were treated surgically with LUCL reconstruction or repair and off-label reconstruction of the capitellar joint surface using a small metal prosthesis designed for metatarsal head resurfacing (HemiCAP toe classic). Results: Five patients (three adolescent males, two adult females) were treated between 2007 and 2018. At a median follow-up of 5 years, all patients had complete relief of their symptomatic instability. No patients had pain at rest, but two patients had mild pain (visual analog scale 1-3) during physical activity. Three patients rated their elbow as normal, one as almost normal, and one as greatly improved. On short-term radiographic follow-up there were no signs of implant loosening. None of the patients needed reoperation. Conclusions: Recurrent PLRI of the elbow associated with an engaging posterior capitellar lesion can be treated successfully by LUCL reconstruction and repair and filling of the capitellar defect with a metal prosthesis. This treatment option has excellent clinical results in the short-medium term. Level of evidence: IV.

• Journal of Periodontal and Implant Science
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• 제47권5호
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• pp.292-311
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• 2017

Purpose: Beyond the limited scope of non-specific polyclonal regulatory T cell (Treg)-based immunotherapy, which depends largely on serendipity, the present study explored a target Treg subset appropriate for the delivery of a novel epitope spreader Pep19 antigen as part of a sophisticated form of immunotherapy with defined antigen specificity that induces immune tolerance. Methods: Human polyclonal $CD4^+CD25^+CD127^{lo-}$ Tregs (127-Tregs) and $na\ddot{i}ve$ $CD4^+CD25^+CD45RA^+$ Tregs (45RA-Tregs) were isolated and were stimulated with target peptide 19 (Pep19)-pulsed dendritic cells in a tolerogenic milieu followed by ex vivo expansion. Low-dose interleukin-2 (IL-2) and rapamycin were added to selectively exclude the outgrowth of contaminating effector T cells (Teffs). The following parameters were investigated in the expanded antigen-specific Tregs: the distinct expression of the immunosuppressive Treg marker Foxp3, epigenetic stability (demethylation in the Treg-specific demethylated region), the suppression of Teffs, expression of the homing receptors CD62L/CCR7, and CD95L-mediated apoptosis. The expanded Tregs were adoptively transferred into an $NOD/scid/IL-2R{\gamma}^{-/-}$ mouse model of collagen-induced arthritis. Results: Epitope-spreader Pep19 targeting by 45RA-Tregs led to an outstanding in vitro suppressive T cell fate characterized by robust ex vivo expansion, the salient expression of Foxp3, high epigenetic stability, enhanced T cell suppression, modest expression of CD62L/CCR7, and higher resistance to CD95L-mediated apoptosis. After adoptive transfer, the distinct fate of these T cells demonstrated a potent in vivo immunotherapeutic capability, as indicated by the complete elimination of footpad swelling, prolonged survival, minimal histopathological changes, and preferential localization of $CD4^+CD25^+$ Tregs at the articular joints in a mechanistic and orchestrated way. Conclusions: We propose human $na\ddot{i}ve$ $CD4^+CD25^+CD45RA^+$ Tregs and the epitope spreader Pep19 as cellular and molecular targets for a novel antigen-specific Treg-based vaccination against collagen-induced arthritis.

• Journal of Periodontal and Implant Science
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• 제32권4호
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• pp.753-767
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• 2002

The purpose of this study was to evaluate histologically the effect of LiF-maleic acid added calcium aluminate(LM-CA) bone cement & CA-PMMA composite bone cement on the healing of calvarial defect in Sprague-Dawley rats. The critical size defects were surgically produced in the calvarial bone using the 8mm trephine bur. The rats were divided in three groups : In the control group, nothing was applied into the defect of each rat. LM-CA bone cement was implanted in the experimental group 1 and CA-PMMA composite bone cement was implanted in the experimental group 2. Rats were sacrificed at 2, 8 weeks after surgical procedure. The specimens were examined by histologic analysis, especially about the bone-cement interface and the response of surrounding tissue. The results are as follows; 1. In the control group, inflammatory infiltration was observed at 2 weeks. At 8 weeks, periosteum and duramater were continuously joined together in the defect area. But the center of defect area was filled up with the loose connective tissue. 2. In the experimental group 1, the bonding between implanted bone cement and the existing bone was seen, which more increased in 8 weeks than 2 weeks. Inflammatory infiltration and the dispersion of implanted bone cement particles were seen in both 2 weeks and 8 weeks. 3. In the experimental group 2, implanted bone itself had a dimensional stability and no bonding between implanted bone cement and the existing bone was seen in both 2 weeks and 8 weeks. Implanted bone cement was encapsulated by fibrous connective tissue. In addition, inflammatory infiltration was seen around implanted bone cement. On the basis of these results, when LM-CA bone cement or CA-PMMA composite bone cement was implanted in rat calvarial defect, LM-CA bone cement can be used as a bioactive bone graft material due to ability of bonding to the existing bone and CA-PMMA can be used as a graft material for augmentation of bone-volume due to dimensional stability.

• 대한소아치과학회지
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• 제43권1호
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• pp.93-108
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• 2016

3D 프린팅 기술이 가장 많이 활용될 수 있는 분야의 하나가 의학분야이다. 3D 프린팅 기술은 최근들어 더욱 상업화되고 프린팅에 사용되는 재료 또한 생체친화성, 생분해성 고분자를 이용 가능하게 됨에 따라 생체의료분야에서의 활용성이 점차적으로 높아지고 있는 경향이다. 생체의료분야에서는 수술 모형을 제작하고 절제범위와 시술 후의 형태를 시술 전에 미리 확인하여 시술시간을 단축하고 부작용을 최소화하고 있으며 인공 골과 장기를 생산함으로써 이식에 따른 부작용을 감소시키고 있다. 또한 보청기, 의족 등 맞춤형 의료 보조용품을 생산하고 있다. 치의학 분야에도 크라운, 덴쳐 등의 보철 수복물 제작, 교정 장치 및 모델 제작, 임플란트 식립이나 외과 수술을 위한 수술용 가이드 제작 등 치과 의료기술을 한 차원 더 높일 수 있을 것으로 전망된다. 그러나 아직은 프린팅 재료(소재), 조형기술, CAD 관련 소프트웨어 기술, 생체안정성과 유효성 검증, 호환성과 표준화 등 해결해야 할 과제가 산적해 있있어 앞으로 이에 대한 지속적인 연구, 개발이 이루어져야 할 것으로 사료된다.

• Journal of Periodontal and Implant Science
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• 제41권6호
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• pp.285-292
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• 2011

Purpose: The aim of this study was to elucidate the effect of a bovine hydroxyapatite/collagen (BHC) block in one-wall intrabony periodontal defects in dogs. Methods: A one-wall intrabony periodontal defect (4 mm wide and 5 mm deep) was prepared bilaterally at the mesial side of the mandibular fourth premolar in five beagle dogs. After thorough root planing, block-type BHC ($4{\times}5{\times}5$ mm) was placed on one side. The contralateral defect area did not receive any material as a sham-surgery control. Histological analysis of the sites was performed after an 8-week healing period. Results: Two of five samples in the experimental group healed well without dissipation of the graft materials, and histological analysis revealed excellent regeneration of the periodontal tissues. However, most of the grafted materials had been displaced in the other three samples, leaving only a small portion of the graft. The measured parameters exhibited large standard deviations, and the mean values did not differ significantly between the experimental and sham-surgery control sides. Conclusions: The application of BHC alone-without a barrier membrane-to wide, one-wall intrabony periodontal defects yielded inconsistent results regarding both periodontal regeneration and substantivity of the graft materials. Thus, the use of a barrier membrane for noncontained-type defects is recommended to improve the stability of the grafted material, and to condense it.

• Journal of Periodontal and Implant Science
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• 제47권2호
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• pp.116-131
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• 2017

Purpose: The entry of bacteria or harmful substances through the epithelial seal of human gingival keratinocytes (HGKs) in the junctional epithelium (JE) is blocked by specialized intercellular junctions such as E-cadherin junctions (ECJs). However, the influence of roughened substrates, which may occur due to apical migration of the JE, root planing, or peri-implantitis, on the development of the ECJs of HGKs remains largely unknown. Methods: HGKs were cultured on substrates with varying levels of roughness, which were prepared by rubbing hydrophobic polystyrene dishes with silicon carbide papers. The activity of c-Jun N-terminal kinase (JNK) was inhibited with SP600125 or by transfection with JNK short hairpin RNA. The development of intercellular junctions was analyzed using scanning electron microscopy or confocal laser scanning microscopy after immunohistochemical staining of the cells for E-cadherin. The expression level of phospho-JNK was assessed by immunoblotting. Results: HGKs developed tight intercellular junctions devoid of wide intercellular gaps on smooth substrates and on rough substrates with low-nanometer dimensions (average roughness $[Ra]=121.3{\pm}13.4nm$), although the ECJs of HGKs on rough substrates with low-nanometer dimensions developed later than those of HGKs on smooth substrates. In contrast, HGKs developed short intercellular junctions with wide intercellular gaps on rough substrates with mid- or high-nanometer dimensions ($Ra=505.3{\pm}115.3nm$, $867.0{\pm}168.6nm$). Notably, the stability of the ECJs was low on the rough substrates, as demonstrated by the rapid destruction of the cell junction following calcium depletion. Inhibition of JNK activity promoted ECJ development in HGKs. JNK was closely associated with cortical actin in the regulation of ECJs in HGKs. Conclusions: These results indicate that on rough substrates with nanometer dimensions, the ECJs of HGKs develop slowly or defectively, and that this effect can be reversed by inhibiting JNK.

• 대한장애인치과학회지
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• 제13권2호
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• pp.95-98
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• 2017

본 증례는 다운 증후군이 있는 환자의 구강 재건 시 CAD/CAM 시스템 사용의 이점을 모색해보았다. 다운 증후군 환자들의 경우, 보철물 파절의 위험성이 크며 불가피하게 보철물을 재제작할 경우, CAD/CAM 시스템의 기존 데이터를 이용하여 최소한의 기공 과정만 진행하여 보철물을 빠른 시일 내에 재제작할 수 있다. 결과적으로 이는 심미적 및 기능적 개선을 통해 삶의 질을 높일 수 있는 보철물 제작 시 환자의 불편감과 치과의사의 노력을 최소화하는 방법이다.

• 대한치과교정학회지
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• 제37권6호
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• pp.400-406
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• 2007

교정치료에서 고정원의 조절은 교정 장치의 선택과 적용에서 가장 중요한 요소 중 하나이다. 이 연구의 목적은 교정용 미니스크류의 식립 즉시 교정력을 적용한 군과 교정력을 적용하지 않은 군의 제거회전력 측정과 조직학적 분석을 통해 즉시 교정력을 가한 미니스크류의 고정원으로서의 안정성을 확인하여 식립 후 교정력을 적용 수 있는 시기의 선택에 도움을 주고자 하는 것이다. 외경 1.6 mm. 길이 8 mm인 총 40개의 타이타늄 미니스크류를 10마리 가토의 경골에 식립하였다. 20개의 미니스크류 실험군은 식립 직후부터 6주 동안 지속적인 200g의 교정력을 적용하였고 나머지 20개의 미니스크류 대조군은 교정력을 적용하지 않았다. 제거 회전력은 디지털 토크 게이지를 이용하여 측정하였으며 t-test를 이용하여 통계처리 하였고, 조직표본은 미니스크류를 제거한 후 H-E 염색하여 조직 소견을 관찰하였다. 제거회전력은 실험군과 대조군에서 통계학적으로 유의성 있는 차이를 보이지 않았으며, 조직학적으로 두 군간의 차이는 없었다. 본 연구의 결과는 교정용 미니스크류에 즉시 교정력을 가하더라도 안정적인 고정원으로 활용 할 수 있다는 점을 제시한다.

• 대한치과보철학회지
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• 제55권2호
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• pp.156-163
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• 2017

1급 지적장애는 일상 생활과 사회 생활의 적응이 현저하게 곤란하여 일생 동안 타인의 보호가 필요한 사람으로 보통 불량한 구강환경을 가지며 치아 우식, 치근단 염증 및 다수의 치아 결손을 보여 적절한 보철적 회복을 필요로 한다. 다수의 치아가 결손된 지적장애 환자의 경우 가철성 보철물의 안정, 유지와 관리가 어렵기 때문에 고정성 보철이 필요하며 임플란트 치료가 유일한 방법이다. 본 증례는 1급 지적장애인 45세 남성환자로 불량한 구강환경으로 인해 대부분의 치아가 상실되어 저작기능 회복을 위해 내원하였으며 임플란트 및 생체친화적이고 강한 강도의 단일 구조 지르코니아를 이용한 고정성 보철물로 최종 수복하였다. 이상의 치료과정 결과 심미적, 기능적으로 만족할 만한 결과를 얻을 수 있었기에 보고하는 바이다.