• The Journal of Advanced Prosthodontics
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• 제8권6호
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• pp.472-478
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• 2016

PURPOSE. The aim of this study was to analyze the shapes of lingual polished surfaces in lower complete dentures formed by polished surface impressions and to provide reference data for use when manufacturing edentulous trays and lower complete dentures. MATERIALS AND METHODS. Twenty-six patients with mandibular edentulism were studied. After lower wax dentures were fabricated, wax was removed from the lingual side of the wax denture and a lingual polished surface impression was obtained with tissue conditioner. The definitive denture was scanned with a three-dimensional scanner, and scanned images were obtained. At the cross-sections of the lingual frenum, lateral incisors, first premolars, first molars, and anterior border of the retromolar pads, three points were marked and eight measurements were taken. The Kruskal-Wallis test and a post hoc analysis with the Mann-Whitney test were performed. RESULTS. Each patient showed similar values for the same areas on the left and right sides without a statistically significant difference. The height of the contour of the lingual polished surface at the lingual frenum was halfway between the occlusal plane and lingual border, it moved gradually in a downward direction. The angle from the occlusal plane to the height of the contour of the lingual polished surface was increased as it progressed from the lingual frenum towards the retromolar pads. CONCLUSION. The shape of the mandibular lingual polished surface was convex at the lingual frenum, lateral incisors and gradually flattened towards the first molars and retromolar pads.

• Journal of Periodontal and Implant Science
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• 제43권2호
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• pp.58-63
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• 2013

Purpose: The aim of this study was to measure the peri-implant bone length surrounding implants that penetrate the sinus membrane at the posterior maxilla and to evaluate the survival rate of these implants. Methods: Treatment records and orthopantomographs of 39 patients were reviewed and analyzed. The patients had partial edentulism at the posterior maxilla and limited vertical bone height below the maxillary sinus. Implants were inserted into the posterior maxilla, penetrating the sinus membrane. Four months after implant insertion, provisional resin restorations were temporarily cemented to the abutments and used for one month. Then, a final impression was taken at the abutment level, and final cement-retained restorations were delivered with mutually protected occlusion. The complications from the implant surgery were examined, the number of failed implants was counted, and the survival rate was calculated. The periimplant bone lengths were measured using radiographs. The changes in initial and final peri-implant bone lengths were statistically analyzed. Results: Nasal bleeding occurred after implant surgery in three patients. No other complications were found. There were no failures of the investigated implants, resulting in a survival rate of 100%. Significantly more bone gain around the implants (estimated difference=-0.6 mm, P=0.025) occurred when the initial residual bone height was less than 5 mm compared to the >5 mm groups. No significant change in peri-implant bone length was detected when the initial residual bone height was 5 mm or larger. Conclusions: This study suggests that implants penetrating the sinus membrane at the posterior maxilla in patients with limited vertical bone height may be safe and functional.

• Journal of Periodontal and Implant Science
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• 제28권2호
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• pp.321-337
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• 1998

The aims of this study were firstly to investigate soft tissue reactions around single implant-supported crowns and secondly to compare soft tissue dimensions and conditions of the crowns in relation to interdental papillae, and lastly to investigate patients'esthetic satisfaction with their single implant-supported crowns according to the interdental papillae presence/absence. Twenty-nine patients (41 implants) whose single missing tooth in the maxillary anterior region had been replaced by single implant-supported crown participated for the study and various variables of soft tissue conditions, dimensions and crown dimensions were measured around the single implant-supported crowns at clinical examination and from study models and slides. The results showed that the soft tissue conditions around the single implantsupported crowns were similar to those around implants used for partially or totolly edentulous patients. Except for the high frequency of bleeding on probing, all other parameters revealed healthy conditions. The buccal sites of the crown had a shallow pocket comparing with other sites. At all sites of the crown, similar status of little inflammation was found. Mesial sites and central-incisor positioned implantsupported crowns had lower contact point position than distal sites and lateral-incisor positioned crowns, respectively. Mucositis index, probing depth and contact point position were significantly correlated with papillae index(p < 0.05). More inflammation and lower contact point position were found at the implant-supported crown with no interdental space than that with interdental space. Patients showed high esthetic satisfaction regardless of interdental space presence. The result indicated that, despite of their submucosal crown margins, single implantsupported crowns have soft tissue conditions as good as other implants used for the treatment of the different types of edentulism and a clinician can manipulate interdental papilla height by modifying crown shapes within the limits of not violating total esthetics.

• 대한치과보철학회지
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• 제43권2호
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• pp.218-231
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• 2005

Statement of problem. In the partially edentulous patients, removable partial dentures have been working as a important treatment modality. Clasps, a kind of direct retainers, received some amount of stresses during the insertion and removal of partial denture on the abutment tooth. Purpose. The study is to investigate stresses of the different clasps. Material and methods. In order to investigate the degree of stresses, maxillary partial edentulism (Kennedy Class II modification I) was assumed and removable partial dentures were designed on it with three kinds of metallic materials; cobalt-chromium alloy, type IV gold alloy and commercially pure (c.p.) titanium. Aker's clasp was applied on the left second molar. RPA (mesial rest-proximal plate-Aker's) clasp was on the left first premolar and wrought wire clasp was on the right first premolar. Three dimensional, non-linear, dynamic finite element analysis method was run to solve this process. Results. 1. Cobalt-chromium alloy had the highest von Mises stress value and c.p. titanium had the lowest one irrespective of the types of clasps. 2. In the Aker's clasps, stress on the retentive tips was shown shortly after the appearance of stresses of the middle and minor connector areas. These time lag was much shorter in the RPA clasps than in the Aker's clasp. 3. In general. retentive tips of wrought wire clasps had much less amount of stress than other clasps. Conclusion. The amount of stress was the highest in the RPA clasp and the lowest in the wrought wire clasp, in general.

• 구강회복응용과학지
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• 제32권3호
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• pp.214-223
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• 2016

임플란트를 보조적으로 이용함으로써 후방 연장 국소의치에 부가적으로 유지와 지지를 얻는 임플란트 보조 국소의치(implant-assisted RPD, IARPD)에 대한 관심이 증가하고 있다. 본 증례는 장기간 후방연장 국소의치의 사용으로 인하여 심하게 기울어진 교합평면을 가진 부분 무치악 환자에서 상악의 고정성 보철 수복과 하악의 지르코니아 교합면을 가지는 임플란트 보조 국소의치를 이용하여 심미적이며 장기적으로 안정적인 교합평면을 가지도록 전악 수복하였으며, 기능적으로 만족스러운 결과를 얻었기에 이를 보고하고자 한다.

• 대한치과보철학회지
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• 제34권3호
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• pp.632-649
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• 1996

The purpose of this study was to examine, by the method of 3-dimentional finite element analysis. how infraocclusion affected the stress distribution in surrounding bone and osseointegrated prosthesis. The 3-dimentional finite element mandibular models were made, in which the first and second molars were removed and the two osseointegrated implants were placed in the first and second molar sites and implant supported fixed prostheses were constructed. Analysis of equivalent stress and displacement induced by strong occlusion or infraocclusion was performed under vertical or inclined distributed loads. The results were as follows; 1. Under vertical load of 50N or 500N, the model in which infraocclusion had not been allowed showed greater stress on implants and the supporting bone than on natural teeth. 2. In the model in which infraocclusion of $30{\mu}m$ had been allowed, implant-prosthesis on the molars had no contact with opposing teeth under vertical load of 50N, However with the same allowed infraocclusion and the model under vertical load of 500N, implant prosthesis on the second molar had contact with opposing teeth, and stress distribution occured properly on natural teeth and implants. 3. Under $45^{\circ}$ inclined load, the model in which infraocclusion had not been allowed showed greater stress on implants and the supporting bone than on natural teeth. There was greater stress in the case of $45^{\circ}$ inclined load than in the case of vertical load. 4. Under $45^{\circ}$ inclined load of 50N or 500N, the model in which infraocclusion of $30{\mu}m$, had been allowed showed no occlusal contact on the implants and occlusal contact on the natural teeth. 5. In partially edentulous cases with implant supported prosthesis, we can prevent excessive load on implants by allowing infraocclusion.

• 대한치과보철학회지
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• 제59권4호
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• pp.415-421
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• 2021

소수 잔존치가 남아있거나 치주적으로 불리한 경우 전통적인 가철성 국소의치의 생역학적 예후가 불분명하다. 이러한 경우, 하이브리드 텔레스코픽 이중관 국소의치(hybrid telescopic double crown RPD)는 성공적인 치료의 대안이 될 수 있다. 이 치료방법의 경우 지대치 간의 이차고정 효과가 있으며 응력의 방향이 수직적이고, 지대치 발치 시에 의치의 수리가 용이하다는 점에서 전통적인 가철성 국소의치에 비해 장점을 보인다. 본 증례에서는 전치부의 과개교합을 가진 상하악의 부분 무치악 환자에 있어 상악에는 이중관 의치, 하악에는 임플란트 및 고정성 보철치료가 시행되었다. 장기간 동안 경과관찰 및 유지관리 치료를 시행한 결과, 기능 및 심미적인 면에서 만족할 만한 성과를 얻었기에 이를 보고하고자 한다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제45권4호
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• pp.199-206
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• 2019

Objectives: In mandibular edentulism, the treatment option with a two-interforaminal implant-retained bridge and a removable partial denture is rarely evaluated in literature. The aim of this in vitro study was to evaluate the stress distribution of this treatment option by comparing it with traditional treatment options with interforaminal implants in the edentulous mandible. Materials and Methods: Two interforaminal implants were placed in a formalin-fixed cadaver mandible, and overdentures with three different types of attachments were fabricated: (1) two ball attachments and an overdenture, (2) a Dolder bar and an overdenture, and (3) screw-retained two-implant inter-canine porcelain fused to a metal bridge and an implant-assisted removable denture (IARD) with precision attachments. Three biting conditions were generated for each denture type, and the strains were documented under vertical loading of 100 N. Results: The calculated strain values from measured strains in all measurement sites and loading conditions for the screw-retained two-implant intercanine porcelain fused to a metal bridge and a cast framework partial denture with precision attachments situation were lower than in the other scenarios (P<0.05). Conclusion: Within the limitations of the present study, it can be concluded that an IARD may be a reasonable and valuable alternative to ball attachments or a bar in two interforaminal implants, especially when the patients prefer to be able to show their teeth even when they take out their removable dentures.

• 대한치과보철학회지
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• 제59권3호
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• pp.350-358
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• 2021

치과치료에 디지털 기술을 접목함으로써 치료 과정을 단순화하고 환자의 불편감을 줄여줄 수 있다. 디지털 기술을 활용한 총의치의 경우 여러 상업적인 시스템들이 나와 있으나 아직 국내에서는 보편적으로 사용되고 있지 않다. 본 증례 보고에서는 단일 환자에서 디지털 및 전통적인 치료 술식으로 제작한 두 쌍의 총의치를 장착한 뒤 이에 대한 환자의 만족도와 유지력, 안정성, 적합도를 비교하였다. 디지털 치료 술식으로 제작한 총의치는 개인화되어 디자인된 밀링된 치아를 이용했기 때문에 이상적 교합을 형성할 수 있었으며, 디지털 치은 디자인을 통해 심미성 또한 확보하여 적절한 기능적, 심미적 임상결과를 보였으나, 전통적 제작 방식에 비해 하악 의치의 유지력이 떨어지는 등의 한계 또한 존재하였기에, 이에 대하여 보고하고자 한다.

• 대한치과보철학회지
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• 제60권4호
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• pp.442-452
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• 2022

무치악 환자의 구강 재건을 위한 임플란트를 활용한 치료 계획으로는 임플란트 지지 고정성 가공 의치, 임플란트 피개 의치, 임플란트 보조 국소의치 등이 있으며, 각각의 방식에 대한 적응증과 장단점이 다양하다. 본 증례의 환자는 상악 국소의치의 모든 잔존 지대치의 발거가 필요했으며 후방부 잔존골이 부족하여 식립 가능한 임플란트의 개수가 한정적이었다. 따라서 골 지지가 양호한 전방부에 4개의 임플란트 식립하여 임플란트 지지 서베이드 크라운과 후방연장 임플란트 보조 국소의치로 수복해주었고 환자에게 경제적으로 효과적이면서도 심미적, 기능적으로 만족스러운 결과를 제공하였다. 상악 무치악 환자에게 이와 같은 치료 계획은 경우에 따라 임플란트 피개의치의 대안으로 사용될 수 있으며 임상적, 생역학적 유효성을 검증하기 위해 더 많은 연구가 필요하다.