• 대한치과보철학회지
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• 제44권4호
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• pp.394-404
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• 2006

Statement of problem: A conventional 3-unit fixed partial denture design with a pontic between two retainers is the most commonly used. However in cases where the mental nerve is in close proximity to the second premolar, a cantilever design can be considered. As such, logical and scientific evidence is lacking for the number and position of implants to be placed for partially edentulous patients, and no clear-cut set of treatment principles currently exist. Purpose : The purpose of this study was to evaluate prognosis of implant-supported fixed partial dentures and to compare changes in bone level which may rise due to the different factors. Material and method : The present study examined radiographical marginal bone loss in patients treated with implant-supported fixed partial dentures (87 prostheses supported by 227 implants) and evaluated the influence of the span of the pontic, type of the opposing dentition. Clinical complications were studied using a retrospective method. Within the limitation of this study. the following result were drawn Result, 1. Seven of a total of 227 implants restored with fixed prostheses failed, resulting in a 96.9% success rate. 2. Complications encountered during recall appointments included dissolution of temporary luting agent (17 cases), porcelain fracture (8 cases), loosened screws (5 cases), gingival recession (4 cases), and gingival enlargement (1 case). 3. Marginal bone loss, 1 year after prosthesis placement, was significant(P<0.05) in the group that underwent bone grafting, however no difference in annual resorption rate was observed afterwards. 4. Marginal bono loss, 1 year post-placement, was greater in cantilever-type prostheses than in centric pontic protheses (P<0.05). 5. Marginal bone loss was more pronounced in posterior regions compared to anterior regions (P<0.05). 6. The degree of marginal bone loss was proportional to the length of the pontic (P<0.05). Conclusion: The success rate of implant-supported fixed partial dentures, including marginal bone loss, was satisfactory in the present study. Factors influencing marginal bone loss included whether bone graft was performed, location of the pontic (s), location of the surgical area in the arch pontic span. Long-term evaluation is necessary for implant-supported fixed partial dentures, as are further studies on the relationship between functional load and the number of implants to be placed.

• 대한치과보철학회지
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• 제43권5호
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• pp.650-661
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• 2005

Statement of problem: It could be hypothesised that attachments, which provide more retention against vortical and horizontal dislodgement, will be associated with more favorable parameters of oral function. Purpose: This study was to provide data of initial retentive force and retention loss of different bar attachment systems recommended for use with maxillary implant overdentures. Material and method: 4 implants were placed in the anterior region of edentulous maxilla, five different systems of bar attachment were fabricated as follows: cantilevered Hader bar using clips (Type 1), Hader bar using clips without cantilever (Type 2), Hader bar using clip and ERA attachment orange male (Type 3), Hader bar using clip and ERA attachment white male (Type 4), and Bar using magnets (Type 5). Each samples were placed in the universal testing machine for determination of retentive forces(at initial and after every 200 cycles up to 1,000 cycles). Results and Conclusion 1. Attachment type 1 showed the biggest initial retentive force followed by type 3, type 2, type 4, and lastly type 5(P<0.001). 2. After 1,000 cycles of repeated removals of attachments, significant loss of retentive forces was taken place except for attachment type 5. 3. After 1,000 cycles of repeated removals, the loss of retentive force between type 1 and type 2, which used Hader bar and clip attachments. was greater in type 1 that had wider clip formation. And between type 3 and type 4, which used ERA attachments, the loss of retentive force was greater in type 4 that had white male attached (P<0.001). 4. After 1.000 cycles of repeated removals, attachment type 3 showed the biggest retentive force followed by type 2, type 4, type 1 and lastly type. 5. There was no significant difference between attachment type 3 and 4, and type 4 and 1(P<0.001).

• 대한치과보철학회지
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• 제53권4호
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• pp.301-309
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• 2015

목적: 이 연구의 목적은 지대주 나사 잔여 전부하 비율과 시멘트 파손유무 평가를 통해 나사 시멘트 유지형 임플란트 보철물(screw- and cement-retained implant prosthesis: SCP)의 임상적 수행 능력을 알아보는 것이다. 재료 및 방법: 구치부 부분 무치악 환자들을 대상으로 임플란트가 식립되었으며 3 - 6개월의 치유기간 후 SCP임플란트 보철물이 장착되었다. 추적관찰을 통해 임플란트의 생존율이 평가되고 보철물 성공률도 평가되었다. SCP 보철물의 나사 잔여 전부하 비율 및 시멘트 파손 비율이 측정되었다. 결과: 20명의 환자로부터 21개의 SCP보철물(43개의 임플란트)이 최대 64개월까지 관찰되었다. 관찰기간(평균 34개월) 동안 골융합에 실패한 임플란트는 하나도 없었다. 지대주, 나사, 도재 혹은 보철물 프레임 파절이나 나사 풀림 등은 없었으므로 보철물 성공율은 100%였다. SCP 보철물의 나사 잔여 전부하 비율은 97.61% (${\pm}16.29$), 그리고 시멘트 파손비율은 9.5%이었다. 결론: 본 실험의 한계 내에서, 나사 풀림과 시멘트 파손이란 관점에서 SCP 디자인의 임플란트 보철물은 양호한 단기 임상 결과를 보였다.

• Journal of Periodontal and Implant Science
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• 제45권3호
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• pp.120-126
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• 2015

Purpose: With the significance of stable adhesion of alveolar bone and peri-implant soft tissue on the surface of titanium for successful dental implantation procedure, the purpose of this study was to apply microgrooves on the titanium surface and investigate their effects on peri-implant cells and tissues. Methods: Three types of commercially pure titanium discs were prepared; machined-surface discs (A), sandblasted, large-grit, acid-etched (SLA)-treated discs (B), SLA and microgroove-formed discs (C). After surface topography of the discs was examined by confocal laser scanning electron microscopy, water contact angle and surface energy were measured. Human gingival fibroblasts (hGFs) and murine osteoblastic cells (MC3T3-E1) were seeded onto the titanium discs for immunofluorescence assay of adhesion proteins. Commercially pure titanium implants with microgrooves on the coronal microthreads design were inserted into the edentulous mandible of beagle dogs. After 2 weeks and 6 weeks of implant insertion, the animal subjects were euthanized to confirm peri-implant tissue healing pattern in histologic specimens. Results: Group C presented the lowest water contact angle ($62.89{\pm}5.66{\theta}$), highest surface energy ($45{\pm}1.2mN/m$), and highest surface roughness ($Ra=22.351{\pm}2.766{\mu}m$). The expression of adhesion molecules of hGFs and MC3T30E1 cells was prominent in group C. Titanium implants with microgrooves on the coronal portion showed firm adhesion to peri-implant soft tissue. Conclusions: Microgrooves on the titanium surface promoted the adhesion of gingival fibroblasts and osteoblastic cells, as well as favorable peri-implant soft tissue sealing.

• 대한치과보철학회지
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• 제45권5호
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• pp.653-664
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• 2007

Statement of problem: The screw detorque value is a measure of the preload remaining in the screw just before detorquing. Purpose: This study evaluated the effect of different screw tightening sequences and tightening methods on detorque values for a well-fitting implant superstructure. Material and method: An implant superstructure that connected directly to four implants (Astra Tech) was fabricated on a fully edentulous mandibular acrylic resin model. Six well-fitting dental stone casts were made with a pickup impression of the superstructure from the acrylic resin model. To evaluate the effect of three screw tightening sequences (1-2-3-4, 2-4-3-1, and 2-3-1-4) and two tightening methods (2-step and 1-step) on the stability of screw joint, the detorque values for a well-fitting implant superstructure were measured twice after screw tightening using 20 Ncm. Detorque values were analyzed using multi-way analysis of variance and two-way analysis of variance at a .05 level of significance. Results: 1. The mean detorque values for three screw tightening sequences were 12.3 Ncm, 12.6 Ncm, and 12.0 Ncm, respectively. 2. The mean detorque values for two screw tightening methods were 12.0 Ncm, and 12.2 Ncm, respectively. 3. The mean of mimimum detorque values for three screw tightening sequences and for two tightening methods were 10.6 Ncm, 11.1 Ncm, 10.5 Ncm, and 9.8 Ncm, respectively. 4. No statistically significant differences among the variables of screw tightening sequence and tightening method were found (p>.05) for detorque values and for mimimum detorque values. Conclusion: Within the limitations of this study, the screw tightening sequence and tightening method did not have a significant effect on the detorque values for a well-fitting implant superstructure.

• 대한치과보철학회지
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• 제55권1호
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• pp.61-70
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• 2017

본 증례에서는 기존의 총의치 사용 환자에서 의치의 이장된 인상면을 스캔하고 이를 삼차원적으로 반전하여 잔존 치조제의 형태를 재현하고, 의치에 방사선 불투과성 마커를 부착한 상태로 스캔 및 CT 촬영을 진행하여 스캔 이미지와 CT 영상이 중첩된 데이터 상에서 임플란트 식립을 계획하였다. 수술 당일에는 치은 형태에 맞게 제작된 맞춤형 지대주와 임시 수복물을 장착하였다. 임플란트 고정체의 골유착이 완료된 이후 최종 보철물을 제작하는 과정에서는 임플란트 식립 전 미리 스캔하여 저장된 임플란트 지대주 이미지 파일과 구강 내 지대주 상태에서 채득된 구강 스캔 이미지를 중첩하였다. 중첩을 통해 얻어진 정확한 지대주 형태 상에서 최종 보철물을 제작함으로써 최종 보철물의 변연 적합도를 높이고 임상 과정을 간소화 할 수 있었다.

• 구강회복응용과학지
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• 제26권2호
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• pp.145-156
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• 2010

치아 우식, 치주 질환, 치아 파절 등으로 다수의 구치가 상실된 환자의 경우 대합치의 정출, 잔존 치아의 과도한 교합 하중으로 인한 교합 외상의 문제가 발생된다. 대합치 정출이 발생된 경우 인접 조직의 성장도 이와 동시에 발생되고 보철을 위한 악간 공간의 상실을 동반하게 되며 교합 외상으로 인한 치아에 동요도 증가 및 교모에 의한 마모도 증가하게 된다. 이러한 구치의 다수 상실, 대합치 정출 및 잔존치의 교모 증가를 동반한 환자에 있어서는 적절한 치주 수술(치관 연장술, 골 절제술 등) 및 수직 교합 고경의 회복을 통한 잔존 치아와 상실된 치아의 수복이 필요하게 된다. 본 증례의 환자는 상실된 구치의 수복을 주소로 내원한 환자로 구치부 상실 및 잔존치의 마모된 치열을 지녀보철 수복을 위한 공간을 위해 수직고경을 증가시켜 치료한 치험예를 문헌 고찰과 함께 보고하고자 한다.

• 구강회복응용과학지
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• 제29권3호
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• pp.224-235
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• 2013

임플란트의 장기적인 성공을 위해 고정체의 형태, 외과적 술식, 골조직의 조건, 보철물 적합성, 주기적인 검사, 환자의 구강 위생 등에 많은 주의가 필요하다. 많은 연구에서 임플란트 지지 보철물의 적합도에 따른 임플란트의 예후에 관해 보고되었다. 보철물이 수동 적합되어야 임플란트의 상부구조및 하부구조에 해로운 응력을 야기하지 않는다고 보고되고 있으나 현재의 임플란트 보철물의 제작과정으로 진정한 수동 적합을 얻는 수 없다고 인정된다. 임상과정과 기공과정을 포함하여 임플란트 치료의 전 과정에서 오차가 발생하며, 이는 보철물을 변형을 야기하고 이는 임플란트 상부 보철물과 지대주 사이의 오차를 발생시킨다. 이러한 오차는 보철물 장착 후 보철물의 파절, 나사의 헐거움(screw loosening), 골소실, 골유착 실패와 같은 문제를 야기한다. 이런 오차에 의한 문제점은 cantilever의 존재, 과도한 교합력이 존재할 경우 더욱 증가된다고 보고되고 있다. 본 연구에서는 ITI 임플란트를 하악골의 견치후방의 무치악부에 3개를 식립하고 4-unit 캔틸레버 고정성 국소의치를 다양한 위치의 $100{\mu}m$ gap을 생성한 후 제작하고 gap을 생성하지 않은 고정성 국소의치와 30 lb의 하중하에서 광탄성 응력분석을 시행하여 응력분포 양상과상대적인 응력의 크기를 비교분석하였다.

• 대한치과보철학회지
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• 제39권5호
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• pp.463-476
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• 2001

Since the treatment of edentulous patients with osseointegrated implant was first introduced more than 30 years ago, implant therapy has become one of the most important dental treatment modalities today. Based on the previous experience and knowledge, $Br{\aa}nemark\;Novum^{(R)}$ protocol was introduced with the concept of simplifying surgical and prosthetic technique and reducing healing time recently. This protocol recommends the installation of three 5mm wide diameter futures in anterior mandible and the prefabricated titanium bars for superstructure fabrication. This study was designed to analyze the stress distribution at fixture and superstructure area according to changes of fixture number, diameter and superstructure materials. Four 3-dimensional finite element models were fabricated. Model 1 - 5 standard fixtures (13mm long and 3.75mm in diameter) & superstructure consisted of type IV gold alloy and resin Model 2- 3 wide diameter fixtures (13mm long and 5.0mm in diameter) & superstructure consisted of type IV gold alloy and resin Model 3-3 wide diameter fixtures (13mm long and 5.0mm in diameter) & superstructure consisted of titanium and resin Model 4-3 wide diameter fixtures (13mm long and 5.0mm in diameter) & superstructure consisted of titanium and porcelain A 150N occlusal force was applied on the 1st molar of each model in 3 directions - vertical($90^{\circ}$), horizontal($0^{\circ}$) and oblique($120^{\circ}$). After analyzing the stresses and displacements, following results were obtained. 1. There were no significant difference in stress distribution among experimental models. 2. Model 2, 3, 4 showed less amount of compressive stress than that of model 1. However, tensile stress was similar. 3. Veneer material with a high modulus of elasticity demonstrated less stress accumulation in the superstructure. Within the limites of this study, $Br{\aa}nemark\;Novum^{(R)}$ protocol demonstrated comparable biomechanical properties to conventional protocol.

• 대한치과보철학회지
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• 제45권6호
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• pp.717-723
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• 2007

Statement of problem. Unreasonable distal cantilevered implant-supported prosthesis can mask functional problems of reconstruction temporarily, but it can cause serious strain and stress around its supported implant and surrounding alveolar bone. Purpose. The purpose of this study was to evaluate strain of implants supporting distal cantilevered fixed prosthesis with two different cantilevered length under distal cantilevered static load. Material and methods. A partially edentulous mandibular test model was fabricated with auto-polymerizing resin (POLYUROCK; Metalor technologies, Stuttgart, Swiss) and artificial denture teeth (Endura; Shofu inc., Kyoto, Japan). Two implants-supported 5-unit screw-retained cantilevered fixed prosthesis was made using standard methods with Type III gold alloy (Harmony C&B55; Ivoclar-vivadent, Liechtenstein, Germany) for superstructure and reinforced hard resin (Tescera; Ivoclar-vivadent, Liechtenstein, Germany) for occlusal material. Two strain gauges (KFG-1-120-C1-11L1M2R; KYOWA electronic instruments, Tokyo, Japan) were then attached to the mesial and the distal surface of each standard abutment with adhesive (M-bond 200; Tokuyama, Tokyo, Japan). Total four strain gauges were attached to test model and connected to dynamic signal conditioning strain amplifier (CTA1000; Curiotech inc., Paju, Korea). The stepped $20{\sim}100$ N in 25 N increments, cantilevered static load 8mm apart (Group I) or 16mm apart (Group II), were applied using digital push-pull gauge (Push-Pull Scale & Digital Force Gauge, Axis inc., Seoul, Korea). Each step was performed ten times and every strain signal was monitored and recorded. Results. In case of Group I, the strain values were surveyed by $80.7{\sim}353.8{\mu}m$ in Ch1, $7.5{\sim}47.9{\mu}m/m$ in Ch2, $45.7{\sim}278.6{\mu}m/m$ in Ch3 and $-212.2{\sim}718.7{\mu}m/m$ in Ch4 depending on increasing cantilevered static load. On the other hand, the strain values of Group II were surveyed by $149.9{\sim}612.8{\mu}m/m$ in Ch1, $26.0{\sim}168.5{\mu}m/m$ in Ch2, $114.3{\sim}632.3{\mu}m/m$ in Ch3, and $-323.2{\sim}-894.7{\mu}m/m$ in Ch4. Conclusion. A comparative statistical analysis using paired sample t-test about Group I Vs Group II under distal cantilevered load shows that there are statistical significant differences for all 4 channels (P<0.05).