• The Journal of Advanced Prosthodontics
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• 제10권3호
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• pp.191-196
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• 2018

PURPOSE. The goal of this study was to evaluate the clinical outcome of single short implants, less than 8 mm in length, placed in the posterior area. MATERIALS AND METHODS. A total of 128 patients (75 male and 53 female, mean age: $52.6{\pm}11.2years$) with 154 implants participated. Implant marginal bone loss, and survival and success rates were measured. RESULTS. The mean follow-up period was $51.35{\pm}24.97months$. A total of 128 implants, 8 mm in length, were placed in patients who had mean marginal bone loss of 0.75 mm. These implants had a survival rate of 95.3%. Twenty-six implants, 7 mm in length, were placed in areas with a mean marginal bone loss of 0.78 mm and had a survival rate of 96.2%. Both marginal bone loss and survival rate were not statistically different among the groups. In the maxilla, 34 implants showed a mean marginal bone loss of 0.77 mm and a survival rate of 97.1%. In the mandible, 120 implants showed a mean marginal bone loss of 0.75 mm and a survival rate of 95.0%. The average marginal bone loss around all implants was $0.76{\pm}0.27mm$ at the last follow-up review after functional loading. The survival rate was 95.6% and success rate was 93.5%. CONCLUSION. In our study, single short implants less than 8 mm in length in the posterior areas had favorable clinical outcomes.

• Journal of Periodontal and Implant Science
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• 제36권4호
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• pp.879-889
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• 2006

The early exposure of cover screws is a common complication of 2-stage implant technique. The exposure of cover screws between stage I and IT surgery may cause inflammation in the soft tissues surrounding the implants, and lead to peri-implantitis or marginal bone loss. The purpose of this study was to evaluate the effect of the early exposure of cover screws on implants placed using 2-stage technique. Two hundred and nineteen implants in 77 patients were examined for cumulative survival rate, radiographic marginal bone level change, cause and frequency of the early exposure. The results were as follows: 1. Twenty-five implants showed early exposure of cover screws with a frequency of 11.4%. 2. Cumulative survival rate of the implants with early cover screw exposure was 88.0%, and that of the implants without cover screw exposure was 96,9%. 3. At the time of stage IT surgery and 1 year after loading, the marginal bone loss was greater around the implants with early exposure of cover screws than around the implants without cover screw exposure(p <0.05), 4, There was no statistically significant difference in the frequency of the early exposure according to the implant diameter, gender, and smoking(p >0,05).

• The Journal of Advanced Prosthodontics
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• 제2권2호
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• pp.54-57
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• 2010

PURPOSE. The aim of this study was to evaluate the periodontal and prosthodontic complications of multiple freestanding implants in the posterior jaws for up to 1 year of function. MATERIALS AND METHODS. Eight patients received 20 implants posterior to canines. Two or more implants were consecutively inserted to each patient. Single crowns were delivered onto the implants. Marginal bone loss, implant mobility, probing depth, and screw loosening were examined to evaluate the clinical success of such restorations for maximum 1 year of functional loading. RESULTS. All the implants performed well during the observation period. Neither periodontal nor prosthodontic complications were found except a slight porcelain chipping. While the marginal bone level was on average 0.09 mm lower around the implant after 6 months of loading, it was 0.15 mm higher after 1 year. CONCLUSION. Within the limits of this investigation, separate single-tooth implant restorations to replace consecutive missing teeth may clinically function well in the posterior jaw.

• Journal of Periodontal and Implant Science
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• 제34권2호
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• pp.303-315
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• 2004

The success and failure of dental implants depends on various factors such as patient's systemic status, quantity and quality of surrounding bone, presence or absence of marginal infection and mechanical loading condition. The measurement of crestal bone changes around the implants is implemental to evaluate the success and long-term prognosis of the implant. This study was to evaluate the cumulative survival rate of the implants which had been placed in the Department of Periodontics, Chonnam National University Hospital between 1992 and 2003, and to observe the crestal bone loss around the implants which had at least 2 consecutive periapical radiographs after connecting the transmucosal abutment. The radiographs were scanned and digitalized, and the crestal bone levels on the mesial and distal surface of implants were measured using Image analyzer (Image Pro Plus, Media Cybernetics, USA), immediately after implant placement, at 2nd surgery, and 3 months, 6 months, 1 year, and every year thereafter. Any bone loss was not observed during the period between the 1stand 2nd surgery, and the bone loss was 0.86 ${\pm}$ 0.92 mm for the first year of loading after connecting the transmucosal abutment. After 1 year of loading, annual bone loss was 0.1 ${\pm}$ 0.27 mm, and total bone loss was 0.90 ${\pm}$ 0.80 mm (during the average follow-up periods of 22.5 ${\pm}$ 25.6 Mos), The implant, with smooth surface, in the mandible, and with the fixed bridge prosthesis showed greater bone loss, compared to those, with the rough surface, in the maxilla and with single crown. In systemically diseased patients (including DM or osteoporosis), the greater bone loss was observed. The cumulative survival rate among 432 implants was 94.10% for 7 years. Among 15 failed implants, 9 implants were removed due to mobility from disintegration of bone-implant interface. From this results, crestal bone loss around the implants were greatest during 1 year after transmucosal abutment connection, and various factors could affect peri-implant bone loss. To prevent and predict the bone loss around the implants and improve the prognosis, further comprehensive maintenance and follow-up schedules are required.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제34권5호
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• pp.571-577
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• 2008

Introduction: Possible etiologic factors associated with bone loss around implants after implantation are surgical trauma, occlusal overload, periimplantitis, presence of micro gap and the formation of biologic distances. Tarnow et al. observed that the crestal bone loss was greater when the distance between the implants was <3mm than when the implants were ${\geq}\;3mm$ apart. The aim of this study was to evaluate the influence of different interimplant distance on marginal bone and crestal bone resorption in the beagle dogs. Materials and methods: The mandibular premolars of 5 dogs were extracted bilaterally. After 12 weeks of healing, each dog received 7 implants. On each side, implants were separated by 2mm (Group 1) and by 5mm (Group 2). After 16 weeks of healing, the dogs were sacrificed. Marginal bone loss was determined through linear measurements made between the implant-abutment junctions and the most coronal portions of the bone in contact with the implant surface. A line was drawn uniting the implant-abutment junctions of the adjacent implants, and a linear measurement was made at the midpoint in the direction of the most coronal peak of the interimplant bone crest to determine the crestal bone loss. Both of them was measured radiologically and histologically. Result and conclusion: In radiological analysis, the mean of marginal bone loss was $1.26{\pm}0.14mm$ for group 1 and $1.23{\pm}0.34mm$ for group 2, the mean of crestal bone loss was $1.10{\pm}0.14mm$ for group 1 and $1.02{\pm}0.30mm$ for group 2. The results were not statistically significant between 2 groups. In histological analysis, the mean of marginal bone loss was $1.63{\pm}0.48mm$ for group 1 and $1.62{\pm}0.50mm$ for group 2, the mean of crestal bone loss was $1.23{\pm}0.35mm$ for group 1 and $1.15{\pm}0.39mm$ for group 2. The differences were also not statistically significant. The clinical significance of this result is that the increase in the crestal bone loss results in the increase in the distance between the base of the interproximal contact of the crowns and the bone crest, and this determines if papilla will be present or absent between implants. Considering this fact, keeping up sufficient interimplant distance is important to minimize crestal bone loss.

• 구강회복응용과학지
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• 제25권4호
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• pp.417-429
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• 2009

골유착성 임플란트가 소개된 이후로 부분 및 무치악 부위에서 사용되어 높은 성공률과 함께 예지성 있는 결과를 보여주는 치료방법으로 인정받고 있다. 그러나 국내에서 개발된 임플란트에 대해서는 임상적이고 객관적인 연구 자료가 불충분하다. 본 연구에서는 31명의 환자에게서 임플란트 경부에 미세나사를 지닌 임플란트 식립 후 평균 21개월의 기간 동안 임플란트의 생존율에 관한 조사를 시행하였고 부하가 가해지는 시점을 기준으로 12개월 간 변연골의 변화를 파노라마사진을 이용하여 측정 관찰하여 다음의 결과를 도출하였다. 총 96개의 임플란트에서 3개의 임플란트가 실패하여 96.9%의 생존율을 보였다. 50대 환자에서 85.7%로 가장 작은 생존율을 보였으며 성별 및 연령에 따른 생존율 및 변연골 흡수량에 대한 통계적 유의성은 존재하지 않았다. 상악에서는 95.7% 하악에서는 100%의 생존율을 보였다. 골이식 여부, 보철물의 종류, 매식체의 길이 및 직경에 따른 생존율의 차이는 통계적으로 유의한 차이를 보이지 않았다. 기능 부하 후 임플란트 변연골 흡수량은 단일 금관 보철물이 연결 고정 보철물에 비해 증가된 양상을 보였으나 임플란트의 직경, 길이, 골이식의 유무, 식립위치에 의해서는 통계적으로 유의한 차이를 보이지 않았다. 이 연구를 통해 경부에 미세나사를 지닌 임플란트 식립 후에 임플란트 변연골 흡수량은 비교적 적게 일어났으며 또한 안정적으로 유지되는 것이 관찰될 수 있었고 이에 따른 장기적인 추적관찰이 필요할 것으로 사료된다.

• Journal of Periodontal and Implant Science
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• 제50권4호
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• pp.209-225
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• 2020

Purpose: Marginal bone loss (MBL) is an important clinical issue in implant therapy. One feature that has been cited as a contributing factor to this bone loss is peri-implant mucosal thickness. Therefore, in this report, we conducted a systematic review of the literature comparing bone remodeling around implants placed in areas with thick (≥2-mm) vs. thin (<2-mm) mucosa. Methods: A PICO question was defined. Manual and electronic searches were performed of the MEDLINE/PubMed and Cochrane Oral Health Group databases. The inclusion criteria were prospective studies that documented soft tissue thickness with direct intraoperative measurements and that included at least 1 year of follow-up. When possible, a meta-analysis was performed for both the overall and subgroup analyses. Results: Thirteen papers fulfilled the inclusion criteria. A meta-analysis of 7 randomized clinical trials was conducted. Significantly less bone loss was found around implants with thick mucosa than around those with thin mucosa (difference, -0.53 mm; P<0.0001). Subgroups were analyzed regarding the apico-coronal positioning, the use of platform-matched vs. platform-switched (PS) connections, and the use of cement-retained vs. screw-retained prostheses. In these analyses, thick mucosa was found to be associated with significantly less MBL than thin mucosa (P<0.0001). Among non-matching (PS) connections and screw-retained prostheses, bone levels were not affected by mucosal thickness. Conclusions: Soft tissue thickness was found to be correlated with MBL except in cases of PS connections used on implants with thin tissues and screw-retained prostheses. Mucosal thickness did not affect implant survival or the occurrence of biological or aesthetic complications.

• 대한치과보철학회지
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• 제35권2호
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• pp.255-264
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• 1997

The conventional osseointegration protocol calls for waiting up to 12 months for ossification of an extraction socket to heal before placing an endosseous implant. In this study, the possibility of placing a pure titanium implant directly into an extraction socket immediately after extraction was investigated. And the marginal bone loss of immediate nonsubmerged and submerged endosseous dental implants placed into extraction sockets was also compared. Pure titanium Nobelpharma Branemark implants and solid screw type ITI implants were placed into premolar extraction sockets of two adult dogs and allowed to heal for a period of 3 months, followed by functional loading of the implant. Radiographic examination was performed before implantation, immediately after implantation and 3, 6, 9, 12 months after implantation. The results obtained were as follows : 1. Immediately placed nonsubmerged ITI implants and submerged Branemark implants showed favorable radiographic osseointegration status and there were minimum marginal bone loss. 2. There were no significant differences in radiographic finding of osseointegration between conventional and immediate implantation. 3. Gingival tissue around implants showed more inflammatory signs than that of adjacent natural teeth. This study suggest that pure titanium Branemark implants and submerged ITI implants have the potential to integrate when placed immediatly after extraction of the teeth and warrants further investigation.

• 대한치과의사협회지
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• 제48권8호
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• pp.615-620
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• 2010

Purpose: The short dental implant is considered as possible solution in the alveolar bone height deficient cases. The aim of this study was to evaluate clinical availability of short implants by measuring the marginal bone loss of short length implants and comparing with that of conventional length implants. Materials and Methods: The groups were composed of patients who had received at least one implant. The samples of this study were selected from patients who with functional loading after prosthetic treatment for 1 year follow up period. The implants with a length of 5.7 mm and 6mm were considered short. (Bicon Dental implants, USA). The experiment group was composed of $4.5{\times}6mm$, $5{\times}6mm$, $6{\times}5.7mm$ implants (total 18 implants were placed in 14 patients, 8 on maxilla, 10 on mandible). The control group was composed of $4.5{\times}8mm$, $5{\times}8mm$, $4.5{\times}11mm$, $5{\times}11mm$. All implants were selected only by implants placed on molar area. We evaluated marginal bone loss in radiographic images at baseline (implant loading) and 3, 6, 12 months after loading. Additionally, crown-to-implant ratio was evaluated, and marginal bone loss according to crown-to-implant ratio after functional loading was analyzed. Results: The short implant group had a mean marginal bone level of $-0.52{\pm}0.69mm$; the 8mm group, $-0.22{\pm}0.82mm$; and the II mm group, $-0.10{\pm}1.09mm$ after I year of functional loading. But significant differences were not detected between three groups at every follow-up period. Crown-to-implant ratio in short implant group was $1.55{\pm}0.23$; 8mm group was $1.15{\pm}0.18$; and 11mm group was $0.92{\pm}0.15$. Additionally, significant differences between three groups were founded. (P<.0001) The greatest marginal bone loss after 1 year follow-up was founded at crown-to-implant ratio 1~1.49 range in short implant. Conclusion: The marginal bone loss of short implants was comparable to that of long implants. So, the short implants can be a clinically acceptable option.

• Journal of Periodontal and Implant Science
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• 제39권1호
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• pp.27-36
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• 2009

Purpose: The stability of periodontal condition and marginal bone level were important to achieve long-term success of dental implant treatment. The aim of this study was to evaluate periodontal conditions and marginal bone loss around 67 GSII(OSSTEM, Seoul, Korea) dental implants with dual-microthread at the neck portion, 1 year after prosthetic loading. Materials and methods: Sixty-seven GS II dental implants in 27 patients(mean age; $47.4{\pm}14.0$ years) who received implant treatments at Pusan National University Hospital, were included in this study. Thirteen US II(OSSTEM, Seoul, Korea) implants with smooth neck design were selected for the control group. Periodontal and radiographic evaluations were carried out at baseline, 6 months and 12 months after prosthetic loading. Results: In the GS II group, plaque index(PI), gingival index(GI) and probing depth(PD) increased as time passed. In the US II group, GI and PD increased. Although marginal bone level was lower in the US II group in all evaluation periods, the changes between the periods were not statistically significant(p>0.05). In each period, periodontal parameters were not statistically significant between groups. Conclusion: One year after prosthetic loading, GS II and US II dental implants showed similar periodontal conditions and marginal bone response, and were within the criteria of success.