Characteristics of contact and distance osteogenesis around modified implant surfaces in rabbit tibiae

최정유,심재혁,In-Sung Luke Yeo 대한치주과학회 2017 Journal of Periodontal & Implant Science Vol.47 No.3

Purpose: Contact and distance osteogenesis occur around all endosseous dental implants. However, the mechanisms underlying these processes have not been fully elucidated. We hypothesized that these processes occur independently of each other. To test this, we used titanium (Ti) tubes to physically separate contact and distance osteogenesis, thus allowing contact osteogenesis to be measured in the absence of possible triggers from distance osteogenesis. Methods: Sandblasted and acid-etched (SLA) and modified SLA (modSLA) implants were used. Both types had been sandblasted with large grit and then etched with acid. The modSLA implants then underwent additional treatment to increase hydrophilicity. The implants were implanted into rabbit tibiae, and half were implanted within Ti tubes. The bone-to-implant contact (BIC) ratio was calculated for each implant. Immunohistochemical analyses of bone morphogenetic protein (BMP)-2 expression and new bone formation (Masson trichrome stain) were performed. Results: The implants outside of Ti tubes were associated with good bone formation along the implant surface. Implantation within a Ti tube significantly reduced the BIC ratio (P<0.001). Compared with the modSLA implants, the SLA implants were associated with significantly higher BIC ratios, regardless of the presence or absence of Ti tubes (P=0.043). In the absence of Ti tubes, the bone adjacent to the implant had areas of new bone formation that expressed BMP-2 at high levels. Conclusions: This study disproved the null hypothesis and suggested that contact osteogenesis is initiated by signals from the old bone that undergoes distance osteogenesis after drilling. This signal may be BMP-2.

Microporous PTFE Membrane on Bone Regeneration in Rat Calvarial Defects

최정유,Yoo-Jung Um,Ui-Won Jung,김창성,조규성,채중규,이용근,김종관,최성호 한국생체재료학회 2009 생체재료학회지 Vol.13 No.3

Novel membrane is always being developed for guided bone regeneration(GBR). The purpose of this study was toevaluate the microporous polytetrafluoroethylene(PTFE) membrane on bone regeneration in rat calvarial defects. Thirty male Sprague-Dawley rats were used in 3 groups. One was the control group with no material used, anotherwas the positive control group which used the resorbable membrane, collagen and the other was the experimentalgroup which used the microporous PTFE membrane. The barrier membranes were applied in the surgically createdstandardized 8 mm cranial defect. The rats were sacrificed at 2 or 8 weeks. The amount of bone regeneration wasassessed histologically and histomorphometrically. The bone formation increased under both barrier membranescompared with the control group. In terms of time, more bone was filled in 8 weeks than 2 weeks. Better boneformation was seen in defects protected by a microporous PTFE barrier when compared with the control and collagengroup. It can be concluded that microporous PTFE membrane is effective in bone regeneration for its biocompatibility,bone formation enhancement, ease of use and space maintenance.

Spiral scanning imaging and quantitative calculation of the 3-dimensional screw-shaped bone-implant interface on micro-computed tomography

최정유,Cham Albert Choi,In-Sung Luke Yeo 대한치주과학회 2018 Journal of Periodontal & Implant Science Vol.48 No.4

Purpose: Bone-to-implant contact (BIC) is difficult to measure on micro-computed tomography (CT) because of artifacts that hinder accurate differentiation of the bone and implant. This study presents an advanced algorithm for measuring BIC in micro-CT acquisitions using a spiral scanning technique, with improved differentiation of bone and implant materials. Methods: Five sandblasted, large-grit, acid-etched implants were used. Three implants were subjected to surface analysis, and 2 were inserted into a New Zealand white rabbit, with each tibia receiving 1 implant. The rabbit was sacrificed after 28 days. The en bloc specimens were subjected to spiral (SkyScan 1275, Bruker) and round (SkyScan 1172, SkyScan 1275) micro-CT scanning to evaluate differences in the images resulting from the different scanning techniques. The partial volume effect (PVE) was optimized as much as possible. BIC was measured with both round and spiral scanning on the SkyScan 1275, and the results were compared. Results: Compared with the round micro-CT scanning, the spiral scanning showed much clearer images. In addition, the PVE was optimized, which allowed accurate BIC measurements to be made. Round scanning on the SkyScan 1275 resulted in higher BIC measurements than spiral scanning on the same machine; however, the higher measurements on round scanning were confirmed to be false, and were found to be the result of artifacts in the void, rather than bone. Conclusions: The results of this study indicate that spiral scanning can reduce metal artifacts, thereby allowing clear differentiation of bone and implant. Moreover, the PVE, which is a factor that inevitably hinders accurate BIC measurements, was optimized through an advanced algorithm.

새롭게 개발된 비정질의 Calcium Phosphate가 백서두개골의 골재생에 미치는 영향

최정유,채경준,김창성,이용근,조규성,채중규,김종관,최성호,Choi, Jung-Yoo,Chae, Gyung-Joon,Kim, Chang-Sung,Lee, Yong-Keun,Cho, Kyoo-Sung,Chai, Joong-Kyu,Kim, Chong-Kwan,Choi, Seong-Ho 대한치주과학회 2007 Journal of Periodontal & Implant Science Vol.37 No.4

Purpose: The purpose of this study was to evaluate the bone regeneration of novel biodegradable amorphous calcium phosphate. Materials and Method: An 8-mm, calvarial, critical-size osteotomy defect was created in each of 20 male Sprague-Dawley rats(weight $250{\sim}300g$). The animals were divided into two groups of 10 animals each and allowed to heal for 2 weeks(10 rats). The first group was the control group and the other group was the experimental group which received the novel biodegradable calcium phosphate. Results: The healing of the calvarium in the control group was uneventful. The histologic results showed little bone formation in the control group. The experimental group which received the novel biodegradable calcium phosphate showed a normal wound healing. There were a lot of new bone formation around the biomaterial in 2 weeks. The bone formation increased in 8 weeks when compared to 2 weeks and there was a significant bone increase as well(P<0.01). The nobel biodegradable calcium phosphate showed statistical significance when compared to the control group (P<0.05). The novel biodegradable calcium phosphate in 8 weeks showed a significant increase in bone formation when compared to 2 weeks $(40.4{\pm}1.6)$(%). The biodegradable calcium phosphate which is made from mixing calcium phosphate glass(CPG), NaCO and NaOH solution, is biocompatible, osteoconductive and has a high potency of bone formation. Conclusion: We can conclude that the novel biodegradable calcium phosphate can be used as an efficient bone graft material for its biodegradability and osteoconductivity.

Considerations for the Survival of Complete Arch Implant-Supported Zirconia Restorations; Status of Antagonistic Arches and Stress Distribution on Frameworks: A Case Report

최정유,심재혁,여인성 대한치의학회 2017 Journal of korean dental science Vol.10 No.2

This report describes two cases of complete arch implant-supported restorations. The first patient had seven dental implants in each arch with monolithic zirconia frameworks. At four weeks’ follow-up, the one-piece maxillary framework was fractured, which was re-designed and re-fabricated using laser-sintered cobalt-chrome alloy. The second patient had four implants in the mandible only. A mandibular monolithic zirconia framework and a maxillary conventional complete denture were fabricated and delivered. At five years’ follow-up, the patient reported no significant discomfort. Careful consideration and monitoring of the status of antagonistic arches and stress distribution on zirconia frameworks were suggested for complete arch implant-supported fixed restorations.

The effects of newly formed synthetic peptide on bone regeneration in rat calvarial defects

최정유,Ui-Won Jung,김창성,Tae-Kwan Eom,Eun-Jung Kang,조규성,김종관,최성호 대한치주과학회 2010 Journal of Periodontal & Implant Science Vol.40 No.1

Purpose: Significant interest has emerged in the design of cell scaffolds that incorporate peptide sequences that correspond to known signaling domains in extracellular matrix and bone morphogenetic protein. The purpose of this study was to evaluate the bone regenerative effects of the synthetic peptide in a critical-size rat calvarial defect model. Methods: Eight millimeter diameter standardized, circular, transosseus defects created on the cranium of forty rats were implanted with synthetic peptide, collagen, or both synthetic peptide and collagen. No material was was implanted the control group. The healing of each group was evaluated histologically and histomorphometrically after 2- and 8-week healing intervals. Results: Surgical implantation of the synthetic peptide and collagen resulted in enhanced local bone formation at both 2 and 8 weeks compared to the control group. When the experimental groups were compared to each other, they showed a similar pattern of bone formation. The defect closure and new bone area were significantly different in synthetic peptide and collagen group at 8 weeks. Conclusions: Concerning the advantages of biomaterials, synthetic peptide can be an effective biomaterial for damaged periodontal regeneration.

구강외 요인을 가지는 구취환자들에 대한 약물치료효과

장재업,김명진,최정유,이상협,김애리,Martha E Nunn,이효정 대한구강악안면병리학회 2010 대한구강악안면병리학회지 Vol.34 No.5

Halitosis is a major problem on social interactions in many people, and oral hygiene control is a major treatment for halitosis. However, medication may be the choice of method for non-oral origin halitosis. The present study evaluated the efficacy of chlorophyllin medication for oral malodor patients with GERD (gastroesophageal reflux disease). 26 patients with halitosis visited Department of Periodontology of Seoul National University Bundang Hospital. VSCs (Volatile Sulfur compounds) level was evaluated according to Chlorophyllin medication after 20 days’ medication. Scaling was conducted after medication, and VSCs level was measured 28 days after scaling. Chlorophyllin medication on the halitosis patients with GERD showed a statistically significant efficacy (P > 0.05). There was no significant effect on the patients without GERD (P>0.05). There was no significant effect s caling before o ne month ( P>0.05). Chlorophyllin was e ffective in t he halitosis patients with GERD. There was no significant difference one month after scaling.

치과위생인식 확산을 위한 위상차 현미경의 사용

김명진,Martha E. Nunn,최정유,류은하,이효정 대한구강악안면병리학회 2013 대한구강악안면병리학회지 Vol.37 No.3

Poor oral hygiene can cause severe periodontal disease. Therefore, it is necessary to educate individuals regarding the importance of maintaining good oral hygiene. To this end, in this study, we evaluated the efficacy of using a phase contrast microscope as an instructional tool for oral hygiene. Forty patients, randomly divided into test and control groups, were recruited 6 months after receiving oral prophylaxis. A phase control microscope was used as a demonstration tool for the test group, and a dentiform model was used to demonstrate the ideal tooth-brushing method for the control group. In the test group, awareness regarding the importance of proper oral hygiene was found to increase by 30%, and in the control group, awareness was increased by 20%. The overall satisfaction with the instructional program was 80% in the test and 70% in the control group. The level of understanding was 99% in the test and 80% in the control group. Instructions were easily followed by 80% of the test and 60% of the control group. Understanding of the program was significantly higher in the test group than in the control group (p < 0.05). The overall satisfaction and understanding of proper oral hygiene was over 70% for both the groups. The phase contrast microscope-based instructional program yielded higher actual practice rates. The phase contrast microscope is desirable tool for motivating patients and spreading awareness regarding the importance of maintaining good oral hygiene.

The histometric analysis of osseointegration in hydroxyapatite surface dental implants by ion beam-assisted deposition

김민경,최정유,채경준,정의원,김성태,이인섭,조규성,김종관,최성호 대한치주과학회 2008 Journal of Periodontal & Implant Science Vol.38 No.2

Purpose: This study compared the effects of coating implants with hydroxyapatite (HA) using an ion beam-assisted deposition (IBAD) method prepared with machined, anodized, sandblasted and large-grit acid etched (SLA) surfaces in minipigs, and verified the excellency of coating method with HA using IBAD. Material and Methods: 4 male Minipigs(Prestige World Genetics, Korea), 18 to 24 months old and weighing approximately 35 to 40 kg, were chosen. All premolars and first molars of the maxilla were carefully extracted on each side. The implants were placed on the right side after an 8 week healing period. The implant stability was assessed by resonance frequency analysis (RFA) at the time of placement. 40 implants were divided into 5 groups; machined, anodized, anodized plus IBAD, SLA, and SLA plus IBAD surface implants. 4 weeks after implantation on the right side, the same surface implants were placed on the left side. After 4 weeks of healing, the minipigs were sacrificed and the implants were analyzed by RFA, histology and histometric. Results: RFA showed a mean implant stability quotient (ISQ) of 75.625±5.021, 76.125± 3.739 ISQ and 77.941±2.947 at placement, after 4 weeks healing and after 8 weeks, respectively. Histological analysis of the implants demonstrated newly formed, compact, mature cortical bone with a nearby marrow spaces. HA coating was not separated from the HA coated implant surfaces using IBAD. In particular, the SLA implants coated with HA using IBAD showed better contact osteogenesis. Statistical and histometric analysis showed no significant differences in the bone to implant contact and bone density among 5 tested surfaces. Conclusion: We can conclude that rough surface implants coated with HA by IBAD are more biocompatible, and clinical, histological, and histometric analysis showed no differences when compared with the other established implant surfaces in normal bone. (J Korean Acad Periodontol 2008;38:363-372) KEY WORDS: Ion beam-assisted deposition method; hydroxyapatite; Purpose: This study compared the effects of coating implants with hydroxyapatite (HA) using an ion beam-assisted deposition (IBAD) method prepared with machined, anodized, sandblasted and large-grit acid etched (SLA) surfaces in minipigs, and verified the excellency of coating method with HA using IBAD. Material and Methods: 4 male Minipigs(Prestige World Genetics, Korea), 18 to 24 months old and weighing approximately 35 to 40 kg, were chosen. All premolars and first molars of the maxilla were carefully extracted on each side. The implants were placed on the right side after an 8 week healing period. The implant stability was assessed by resonance frequency analysis (RFA) at the time of placement. 40 implants were divided into 5 groups; machined, anodized, anodized plus IBAD, SLA, and SLA plus IBAD surface implants. 4 weeks after implantation on the right side, the same surface implants were placed on the left side. After 4 weeks of healing, the minipigs were sacrificed and the implants were analyzed by RFA, histology and histometric. Results: RFA showed a mean implant stability quotient (ISQ) of 75.625±5.021, 76.125± 3.739 ISQ and 77.941±2.947 at placement, after 4 weeks healing and after 8 weeks, respectively. Histological analysis of the implants demonstrated newly formed, compact, mature cortical bone with a nearby marrow spaces. HA coating was not separated from the HA coated implant surfaces using IBAD. In particular, the SLA implants coated with HA using IBAD showed better contact osteogenesis. Statistical and histometric analysis showed no significant differences in the bone to implant contact and bone density among 5 tested surfaces. Conclusion: We can conclude that rough surface implants coated with HA by IBAD are more biocompatible, and clinical, histological, and histometric analysis showed no differences when compared with the other established implant surfaces in normal bone. (J Korean Acad Periodontol 2008;38:363-372) KEY WORDS: Ion beam-assisted deposition method; hydroxyapatite;

The effects of Hydroxyapatite nano-coating implants on healing of surgically created circumferential gap in dogs

채경준,임현창,최정유,정성민,이인섭,조규성,김종관,최성호 대한치주과학회 2008 Journal of Periodontal & Implant Science Vol.38 No.2

Purpose: The aim of this study is to compare the healing response of various Hydroxyapatite(HA) coated dental implants by Ion-Beam Assisted Deposition(IBAD) placed in the surgically created circumferential gap in dogs. Materials and methods: In four mongrel dogs, all mandibular premolars and the first molar were extracted. After an 8weeks healing period, six submerged type implants were placed and the circumferential cylindrical 2mm coronal defects around the implants were made surgically with customized step drills. Groups were divided into six groups : anodized surface, anodized surface with 150nm HA and heat treatment, anodized surface with 300nm HA and heat treatment, anodized surface with 150nm HA and no heat treatment, and anodized surface with 150nm HA, heat treatment and bone graft, anodized surface with bone graft. The dogs were sacrificed following 12 weeks healing period. Specimens were analyzed histologically and histomorphometrically. Results: During the healing period, healing was uneventful and implants were well maintained. Anodized surface with HA coating and 430゜C heat treatment showed an improved regenerative characteristics. Most of the gaps were filled with newly regenerated bone. The implant surface was covered with bone layer as base for intensive bone formation and remodeling. In case that graft the alloplastic material to the gaps, most of the coronal gaps were filled with newly formed bone and remaining graft particles. The bone-implant contact and bone density parameters showed similar results with the histological findings. The bone graft group presented the best bone-implant contact value which had statistical significance. Conclusion: Within the scope of this study, nano-scale HA coated dental implants appeared to have significant effect on the development of new bone formation. And additional bone graft is an effective method in overcoming the gaps around the implants. (J Korean Acad Periodontol 2008;38:373-384) Purpose: The aim of this study is to compare the healing response of various Hydroxyapatite(HA) coated dental implants by Ion-Beam Assisted Deposition(IBAD) placed in the surgically created circumferential gap in dogs. Materials and methods: In four mongrel dogs, all mandibular premolars and the first molar were extracted. After an 8weeks healing period, six submerged type implants were placed and the circumferential cylindrical 2mm coronal defects around the implants were made surgically with customized step drills. Groups were divided into six groups : anodized surface, anodized surface with 150nm HA and heat treatment, anodized surface with 300nm HA and heat treatment, anodized surface with 150nm HA and no heat treatment, and anodized surface with 150nm HA, heat treatment and bone graft, anodized surface with bone graft. The dogs were sacrificed following 12 weeks healing period. Specimens were analyzed histologically and histomorphometrically. Results: During the healing period, healing was uneventful and implants were well maintained. Anodized surface with HA coating and 430゜C heat treatment showed an improved regenerative characteristics. Most of the gaps were filled with newly regenerated bone. The implant surface was covered with bone layer as base for intensive bone formation and remodeling. In case that graft the alloplastic material to the gaps, most of the coronal gaps were filled with newly formed bone and remaining graft particles. The bone-implant contact and bone density parameters showed similar results with the histological findings. The bone graft group presented the best bone-implant contact value which had statistical significance. Conclusion: Within the scope of this study, nano-scale HA coated dental implants appeared to have significant effect on the development of new bone formation. And additional bone graft is an effective method in overcoming the gaps around the implants. (J Korean Acad Periodontol 2008;38:373-384)