• The Journal of Advanced Prosthodontics
• /
• v.12 no.5
• /
• pp.316-321
• /
• 2020

PURPOSE. The stress distribution and microgap formation on an implant abutment structure was evaluated to determine the relationship between the direction of the load and the stress value. MATERIALS AND METHODS. Two types of three-dimensional models for the mandibular first molar were designed: bone-level implant and tissue-level implant. Each group consisted of an implant, surrounding bone, abutment, screw, and crown. Static finite element analysis was simulated through 200 N of occlusal load and preload at five different load directions: 0, 15, 30, 45, and 60°. The von Mises stress of the abutment and implant was evaluated. Microgap formation on the implant-abutment interface was also analyzed. RESULTS. The stress values in the implant were as follows: 525, 322, 561, 778, and 1150 MPa in a bone level implant, and 254, 182, 259, 364, and 436 MPa in a tissue level implant at a load direction of 0, 15, 30, 45, and 60°, respectively. For microgap formation between the implant and abutment interface, three to seven-micron gaps were observed in the bone level implant under a load at 45 and 60°. In contrast, a three-micron gap was observed in the tissue level implant under a load at only 60°. CONCLUSION. The mean stress of bone-level implant showed 2.2 times higher than that of tissue-level implant. When considering the loading point of occlusal surface and the direction of load, higher stress was noted when the vector was from the center of rotation in the implant prostheses.

• Journal of Korean society of Dental Hygiene
• /
• v.12 no.4
• /
• pp.759-770
• /
• 2012

Objectives : The purpose of this study was to examine the awareness of implant wearers about periodontal diseases and implant management, which were closely linked to implant durability, in an effort to obtain information on the right directions for oral health education related to implant self-care and specialized care. Methods : The subjects in this study were 217 patients who wore implant and visited 14 different dental hospitals and clinics in the metropolitan area. After a questioaire survey was conducted and collected data were analyed by the statistical package SPSS 18.0. Results : As for the awareness of the subjects on the regeneration of alveolar ridge by general characteristics, there were statistically significant intergroup gaps according to the number of possessed implant, implant satisfaction and subjective gingival health status(p<0.05). Regarding their awareness of implant durability by general characteristics, there were statistically significant gaps according to the number of possessed implant and oral health education experience(p<0.05). Concerning their awareness of the cycle of regular implant checkup by general characteristics, there were statistically significant gaps according to occupation, subjective gingival health status and oral health education experience(p<0.05). Conclusions : The above-mentioned findings suggest that in order to ensure the long-term safe maintenance of implant, the way of looking at periodontal diseases and implant management should be changed. Specifically, more intensive oral health education should be provided for implant wearers to be aware of the importance of self-care and specialized care to change their oral health behavior, and clinical dental hygienists should improve their role performance to make it happen.

• Journal of Periodontal and Implant Science
• /
• v.38 no.3
• /
• pp.529-534
• /
• 2008

Purpose: The objective of this study was to compare initial implant stability measured by RFA between different implant systems during the initial healing period. Material and Methods: Fifty-four patients (36 males/18 females) who had been treated at the Department of Periodontology, Chonbuk National University Dental Hospital during the period between January and November in 2007 were included in the study. The mean age of the subjects was 49 years old (18 to 77). A total of 104 implants (Type A: 3i $Osseotite^{(R)}$, Type B: $Replace^{(R)}$ select, Type C: ITI implant) were placed following the manufacturer's standard surgical protocols. Implant stability quotient (ISQ) readings were obtained for each implant at the time of surgery, 2-, and 4-month postoperatively. Result: No implant was failed during the observation period. At the baseline, the difference between mean ISQ values of 3 implant systems was statistically significant (p<0.05). However, at 2-, and 4-month following implant surgery, no significant difference was observed between ISQ values of the implant systems. In the same implant, the ISQ values of Type B and C implants increased (p<0.05), but those of Type A implants decreased during the 2-month healing period. The mean ISQ values of Type B and C implants showed a increasing tendency, while those of Type A implants were stable for the 4-month follow-up period. Conclusion: Within limits of this study, it can be concluded that implant design and surface topography of implant might influence the ISQ value and changing pattern during the initial healing period.

• Journal of Periodontal and Implant Science
• /
• v.40 no.3
• /
• pp.139-143
• /
• 2010

Purpose: Pink gingival esthetic especially on the anterior teeth has been an important success criterion in implant-supported restoration. Inter-implant papillae are a critical factor for implant esthetics, and various techniques for inter-implant papilla reconstruction have been introduced. The aim of this study is to suggest and evaluate a surgical technique for reconstructing inter-implant papillae. Methods: A 28-year-old man had an implant placed on the #13 and #14 area. Four months after implant placement, a second stage surgery was planned for inter-implant papilla reconstruction. At the time of the abutment connection, I-type incisions were performed on the #13i & #14i area followed by full-thickness flap elevation and connection of a healing abutment on underlying fixtures without suture. Results: Two weeks after the second stage implant surgery, soft tissue augmentation between the two implants was achieved. Conclusions: I-shaped incisions for papilla reconstruction performed during the second stage implant surgery were useful for inter-implant papilla reconstruction and showed a good esthetic result.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.42
• /
• pp.13.1-13.6
• /
• 2020

Background: The aim of this study was to evaluate the factors that may affect implant fixture fractures. Methods: Patients who experienced implant fixture removal at Seoul National University Bundang Hospital from 2007 to 2015 due to implant fixture fracture were included. Implant/crown ratio, time of implant fracture, clinical symptoms before implant fracture, treatment of fractured implants, and the success and survival rate of the replaced implants were evaluated retrospectively. Results: Thirteen implants were fractured in 12 patients. Patient mean age at the time of fracture was 59.3 years. Of the 13 implants, 7 implants were placed at our hospital, and 6 were placed at a local clinic. The mean crown/implant ratio was 0.83:1. The clinical symptoms before fracture were screw loosening in five implants, marginal bone loss in five implants, and the presence of peri-implant diseases in five implants. All the fractured implants were removed, and 12 out of the 13 sites were re-implanted. Parafunctions were observed in two patients: one with bruxism and one with attrition due to a strong chewing habit. Conclusions: Several clinical symptoms before the fracture of an implant can predict implant fixture failure. Therefore, if these clinical symptoms are observed, appropriate treatments can be taken before more serious complications result.

• The Journal of Korean Academy of Prosthodontics
• /
• v.35 no.1
• /
• pp.165-180
• /
• 1997

The purpose of this study was to observe bone apposition and marginal bone loss and to check the possibility of success on titanium implant, HA coated implant and the implant with natural coral that were place immediately after teeth extraction in dogs. Experimental subjects were divided into 4 groups ; the 1st group is the titanium implant, second the HA coated implant, third the implant with natural coral, and the last the control group that was prepared in the extraction sockets. After 12 weeks, the dogs were sacrificed for visual observation and microscopic examination approaching histologic and histomorphometric analysis. The results were as follows : 1. Neither the infection nor the exposure of implant was found at the sites of all implant. 2. In a histomorphometric analysis, mean percentage of direct bone contact with the titanium implant was 80.7% and the HA coated implant showed 81.5% apposition, but the implant with natural coral showed 64.9% apposition(P<0.05). 3. In a microscopic examination, mature lamellated bone was found around the immediate implants and control group, while unabsorbed natural coral around the immediate implants with natural coral was found. 4. All immediate implant groups showed the loss of marginal bone in order from implant with natural coral, titanium implant, and HA coated implant. 5. Implant with natural coral that was placed by the type I interface of the Barzilay's classification immediately after teeth extraction showed low percentage of direct bone contact area, low success rate and a lot of marginal bone loss. Above results suggested that the immediate implants are osseointegrated successfully, although slightly marginal bone was loss.

• The Journal of Korean Academy of Prosthodontics
• /
• v.35 no.3
• /
• pp.577-608
• /
• 1997

The purpose of this study is to evaluate the stress distribution in the bone around dental implants supporting mandibular overdenture according to the number of implant and the type of attachment. Two or four implants were placed in an edentulous mandibular model and three dimensional photoelastic stress analysis was carried out to measure the fringe order around the implant supporting structure and also to calculate principal stress components at cervical area of each implant. The attachments tested were rigid and resilient type of Dolder bar, Round bar, Hader bar and Dal-Ro attchment. The results were as follows ; 1. In 2-implant supported overdenture using Round bar, Hader bar, and Dal-Ro attachment, compressive stress pattern was observed on the supporting structure of implant on loaded side, while tensile stress pattern in unloaded side. 2. In 2-implant supported overdenture using Dolder bar, the rigid Dolder bar shared the occlusal loads between 2 implants in a more favorable manner than was exhibited by the resilient type, while the resilient type placed a more stress on the distocervical area of the implant on the loaded side. But compressive stress pattern was observed in both the loaded and unloaded sides in either case. 3. In 2-implant supported overdenture, rigid and resilient type of Dolder bar exhibited more cross arch involvement than the Round bar, Hader bar, or Dal-Ro attachment. 4. In 4-implant supported overdenture using resilient Dolder bar and Hader bar, stress turned out to be distributed evenly among the implants between loaded and unloaded side, but thor was no reduction in the magnitude of the stress in the surrounding structure of implant contratry to 2-implant supported overdenture. 5. The stress pattern at cervical area of implant was different with the number of implant or the type of attachment but the overload, harmful to surrounding structure of implant, was not observed.

• The Journal of the Korean dental association
• /
• v.55 no.10
• /
• pp.716-724
• /
• 2017

Past literatures stressed that when a gap occurred between smooth surface implant and alveolar bone, osseointegration was unsatisfactory at histologic examination regardless of clinical findings. Accordingly, standard surgical approach in the early days of implant surgery was to place the implant after all gap was healed. However, Botticelli et al.(2004) reported high degree of osseointegration at the gap with SLA surface implant. From then, the era of immediate implantation has begun because SLA surface implant make gap healing possible. There are two main disadvantages of immediate implantation: (1) surgical technique is sensitive for primary implant stability, (2) Implant placement at the accurate position that predicts external change of extraction wound is required. Immediate implantation has outstanding advantages in all perspectives except for the above-mentioned disadvantages. Therefore, it would be unwise to abandon the option of immediate implantation simply due to surgical difficulties. The purpose of this paper is to describe the necessity of immediate implantation and to present scientific evidence for immediate implantation and accurate implant position by literature review.

• The Journal of the Korean dental association
• /
• v.25 no.8 s.219
• /
• pp.735-739
• /
• 1987

implant라는 것은 생리학적으로 생체에 있어서 이물이라는것을 인식해야 한다. 또 그 일부를 상부구조물을 제작하기 위하여 구강내에 노출시킴으로써 연조직과의 접촉부위가 감염으로 염증상태를 지속하고 있다. 그뿐아니라 저작시에 교합압에 의한 위격으로 골내에 여러 가지 변화를 일으킨다. 이와같이 생체내에 이물를 implant 하였을 때 생기는 반응은 생체의 방어기전으로서 염증을 일으키는데 이 염증의 진도에 따라 동화, 흡수, 배제중의 어느 하나로 결말짓게 된다. 따라서 implant를 시술하였을때 생기는 조직의 반응을 최소한으로 감소하기 위한 생물학적 적응조건으로서 재료, 약물, 기구, 시술방법 등을 잘 선택하는 것이 implant의 임상응용에 요절이 되는것이다. implant의 종류는 실로 다양다종이다. 그러나 어떤 implant와 시술방법을 선택하든지 악골에 접착, 또는 식위하여 견고하게 장착되어 그 implant된 자체를 통하여 가장 천연치에 가까운 기능을 얻는것이 implant의 시술목적이다. 임상의가 implant를 시술하면서 이것이 과연 성공할것인가? 즉 저작효율과 내구연한이 얼마나 갈것인가 우려하지 않을수 없다. 그러므로 그 우려를 덜고 성공으로 이끄는 임상상의 문제점을 찾아 논하기로 한다.

• Journal of the Korean Academy of Esthetic Dentistry
• /
• v.27 no.1
• /
• pp.41-50
• /
• 2018

Guided implant surgery is useful in anterior implant case in terms of fixture installation and temporary crown delivery. For the aesthetic prosthetics in anterior implant, the position of the implant fixture is crucial. Guided surgery is the top-down procedure and we designed prosthetics first and then determine the position of the fixture. Guided surgery can reduce the stress of dentist with difficult anterior implant case.