• Journal of Periodontal and Implant Science
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• v.37 no.3
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• pp.535-542
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• 2007

Background : Repeated dis/re-connection of implant abutment caused bone loss around implant fixtures due to the new formation of biologic width of the mucosal-implant barrier. The aim of this clinical study was to evaluate whether the repeated dis/re-connection of implant abutment cause bone loss clinically and the effect of cleansing methods on a bone loss during the early healing period. Methods : A total 50 implants were installed in 20 patients and repeated dis/re-connection of abutment was performed at the time of surgery and once per week for 12 weeks. 0.9% normal saline solution as group1 and 0.1% chlorhexidine solution as group 2 was used to clean abutments. All patients had radiographs taken at the placement of implant and 4, 8, and 12 weeks postoperatively. The data for bone loss around implant were analyzed. Results: The marginal bone loss at 12 weeks were $1.28{\pm}0.51mm$, $1,32{\pm}0,57mm$ in the mesial and distal sides in group1, $1.94{\pm}0.75mm$, $1.81{\pm}0.84mm$ in group 2, respectively. In view of marginal bone loss, there was not a significant statistical difference between groups. Conclusions : Repeated dis/re-connection of implant abutment may not cause marginal bone loss around implant fixture although limited samples and short-term observation period. In spite of more bone loss in group 2, there was no statistical significant difference between groups. In context of those results, the clinical significance of the repeated dis/re-connection of implant abutment and the cleansing method of abutments is debatable when it comes to marginal bone loss during early healing period.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.6
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• pp.760-768
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• 2007

Statement of problem. Conventional denture treatment for totally edentulous patients is associated with a variety of functional and psychosocial problems. The placement of implants in the anterior region of the maxilla and mandible and the fabrication of an implant-retained overdenture might solve these problems. Purpose. This study compared the marginal bone loss around the implant and evaluated the implant survival rate and complications in patients treated with overdentures retained by implants for 2 years. Material and methods. Patients who had received implant-retained overdentures using a Dolder bar at Samsung Medical Center from January 1999 to June 2005 and had participated in the annual recall programs for two years were selected for this study. A total of 18 patients and 56 $Br{\aa}ne-mark\;system^{(R)}$ implants were used, and their data were reviewed. Evaluations of the survival rate, bone quality, marginal bone loss, and complications were performed. The data on the Dolder bar length and clip length were measured. The change in marginal bone loss and the correlation between the marginal bone loss and bar length, clip length, or bone quality were investigated. Results. Implants placed in this study showed a 100% survival rate. The average annual bone loss was 1.12mm in the first year and 0.27mm in the second year in the maxilla, and 0.58mm in the first year and 0.22mm in the second year in the mandible. The marginal bone loss in the maxilla showed no significant association with those in the mandible. (P>.05). There was no significant difference in marginal bone loss around implants between the first and second year. (P>.05) There was no statistically significant relationship (P>.05) between the marginal bone loss and bone quality, clip length, or Dolder bar length. The Dolder bar length showed a high correlation with the clip length. (P<.05) Various complications were noted. Conclusion. These results confirmed the favorable outcome for patients treated with implant-retained overdentures.

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

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.35 no.4
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• pp.240-247
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• 2009

Purpose: The purpose of this study was to evaluate marginal bone loss to the bone crest functionally loaded for up to eighteen months and also with regard to other variables of interest. Material and Methods: 135 endosseous implants(GS II, Osstem, South Korea) were placed in 35 patients. The design of GS II implant is straight with the microthread. Radiographic examinations were conducted at baseline (implant loading) and 3, 6, 9, 12 and 18 months after loading. Marginal bone level measurement was made from the reference point to the lowest observed point of contact of the marginal bone with the fixture. The reference point of the fixture was the border between the blasted surface and machined surface of the fixture. Results: Implants were on function for a mean 12.7 months(range, 3?18 months). For the 56 maxillary and 79 mandibular implants, mean marginal bone loss was 0.68 mm and 0.70 mm. Implants placed maxillary posterior area displayed more crestal bone loss than the other position. The difference between mesial and distal bone levels was statistically significant (p<0.05) with respective means of 0.51 mm and 0.62 mm. Also, The difference between bone graft group and no-bone graft group was statistically significant(p<0.05) with respective means of 0.38 mm and 0.66 mm. But no statistically significant influence of sex, type of surgery(one or two stage surgery), the implant length was observed(p>0.05). Conclusion: This study indicates the amount of marginal bone loss around implant has maintained a relative stable during follow-up periods.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.6
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• pp.806-815
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• 1998

Regular radiographic examination has been considered as an essential diagnostic method for the osseointegrated dental implantation. This study investigated the marginal bone loss through the measurement on the periapical radiograph around 46 endosseous dental implants. Marginal bone loss have been observed for 5 years after delivery of prostheses. The results were as follows : 1. According to the experimental periods, average marginal bone loss in total implant was 1.821mm in the first year, 1.833mm in the second, 1.892mm at third, 1.910mm at forth and 1.957mm at fifth after delivery of prostheses(P<0.05). 2. The average bone loss was 1.832mm in the maxillae and 1.819mm in the mandible in three years but there was no significant difference between the upper and lower jaw(P>0.05). 3. The average bone loss was 1.824mm in males and 1.818mm in females in five years but there was no significant difference according to the sex(P>0.05). These results indicate that the most of the alveolar bone loss occur within the first year after delivery of dental prostheses resulting in the exposure of polished neck positions, and the bone level stabilizes at first thread portion of the implant fixtures.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.34 no.6
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• pp.440-448
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• 2012

Purpose: The purpose of this study was to evaluate marginal bone loss of the alveolar crest on implants with or without guided bone regeneration and variables that have influenced. Methods: The clinical evaluation were performed for survival rate and marginal bone loss of 161 endosseous implants installed with guided bone regeneration (GBR) in 83 patients from September 2009 to October 2010 in relation to sex and age of patients, position of implant, implant system, length and diameter of implant. Study group (n=42) implant with GBR procedure, control group (n=41) implant without GBR technique. Simultaneous GBR approach using resorbable membranes combined with autogenous bone graft or freeze-dried bone allograft or combination. Radiographic examinations were conducted at healing abutment connection and latest visit. Marginal bone level was measured. Results: Mean marginal bone loss was 0.73 mm in study group, 0.63 mm in control group. Implants in maxillary anterior area (1.21 mm) were statistically significant in study group (P<0.05), maxillary posterior area (0.81 mm) in control group (P<0.05). Mean marginal bone loss 1.47 mm for implants with diameter 3.4 mm, 0.83 mm for implants of control group with diameter 4.0 mm (P<0.05). Some graft materials showed an increased marginal bone loss but no statistically significant influence of sex, implant type or length. Conclusion: According to these findings, this study demonstrated the amount of marginal bone loss around implant has maintained a relative stable during follow-up periods. We conclude that implants with GBR had similar survival rate and crestal bone level compared with implants in native bone.

• Journal of Dental Rehabilitation and Applied Science
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• v.31 no.1
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• pp.33-44
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• 2015

Purpose: This study is to evaluate the clinical significance of the platform switching concept by comparing the marginal bone loss around platform-matched and platform-switched implants. Materials and Methods: Date of implant placement, diameter, length, implant-abutment connection type and absence of splinting prosthesis were investigated on patients who performed treatment with implant placement at Wonkwang University Dental Hospital Implant Center. To measure the marginal bone loss around implants, periapical radiographs of patient were used when implant was placed and when visited the center most recently by using the program, Emago advanced v5.6. Results: As a result of observing on 150 implants of 82 patients for 6 - 63 months, platform-matched implants showed $1.16{\pm}0.54mm$, platform-switched implants showed $0.68{\pm}0.27mm$ of marginal bone loss. Conclusion: It was considered that there is the positive effect to reduce marginal bone loss around platform-switched implants.

• Journal of Periodontal and Implant Science
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• v.42 no.6
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• pp.231-236
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• 2012

Purpose: The aim of this study was to evaluate the influence of the crown-to-implant (C/I) ratio on the change in marginal bone level around the implant and to determine the site-related factors influencing the relationship between the C/I ratio and periimplant marginal bone loss. Methods: A total of 259 implants from 175 patients were evaluated at a mean follow-up of five years. Implants were divided into two groups according to their C/I ratios: ${\leq}$ 1, and >1. Site-related factors having an influence on the relationship between C/I ratio and periimplant marginal bone loss were analyzed according to the implant location, implant diameter, implant manufacturer, prosthesis type, and guided bone regeneration (GBR) procedure. Results: It was found that 1) implants with a C/I ratio below 1 exhibited greater periimplant marginal bone loss than implants with a C/I ratio more than 1, 2) site-related factors had an effect on periimplant marginal bone loss, except for the implant system used, 3) the C/I ratio was the factor having more dominant influence on periimplant marginal bone loss, compared with implant diameter, prosthesis type, implant location, and GBR procedure, 4) implants with a C/I ratio below 1 showed greater periimplant marginal bone loss than implants with a C/I ratio greater than 1 in the maxilla, but not in the mandible, 5) and periimplant marginal bone loss was more affected by the implant system than the C/I ratio. Conclusions: Within the limitations of this study, implants with a higher C/I ratio exhibited less marginal bone loss than implants with a lower C/I ratio in the posterior regions. The C/I ratio was a more dominant factor affecting periimplant marginal bone loss in the maxilla than the mandible. Meanwhile, the implant system was a more dominant factor influencing periimplant marginal bone loss than the C/I ratio.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.6
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• pp.483-489
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• 2011

Introduction: This study examined the cumulative resorption of implants placed in a severely atrophic mandible and analyzed the radiologic bone resorption in the marginal bone, after an autogenous bone graft including both block and particulates that had been harvested from the ramus and iliac crest. Materials and Methods: A retrospective study was performed on patients who had bone grafts for augmentation followed by implant installation in the mandible area from 2003 to 2008. Twelve patients (6 men and 6 women) who received 34 implants in the augmented sites were evaluated. Cumulative radiologic resorption around the implants was measured immediately, 3 months, 6 months and 12 months after implant installation surgery. Results: The installed implant in grafted bone showed 0.84 mm marginal bone resorption after 3 months and 50% total cumulative resorption after 1 year. The mean marginal bone resorption around the implant installed in the grafted bone was 0.44 mm after 3 months, 0.52 mm after 1 year, after which it stabilized. The implant survival rate was 97% (failed implant was 1/34). Marginal bone resorption of the installed implant in the autogenous onlay block bone grafts was 0.98 mm after 3 months, which was significantly higher than that of a particulated bone graft (0.74 mm) (P <0.05). Conclusion: An autogenous graft including block type and particulate type is a predictable procedure for the use of dental implants in a severely atrophic mandible. Implant placement in augmented areas show a relatively high survival and minimal bone loss, as revealed by a radiologic evaluation.

• Journal of Periodontal and Implant Science
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• v.52 no.6
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• pp.496-508
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• 2022

Purpose: This study aimed to compare the long-term survival rate and peri-implant marginal bone loss between different types of dental implant-abutment connections. Methods: Implants with external or internal abutment connections, which were fitted at Gangneung-Wonju National University Dental Hospital from November 2011 to December 2015 and followed up for >5 years, were retrospectively investigated. Cumulative survival rates were evaluated for >5 years, and peri-implant marginal bone loss was evaluated at 1- and 5-year follow-up examinations after functional loading. Results: The 8-year cumulative survival rates were 93.3% and 90.7% in the external and internal connection types, respectively (P=0.353). The mean values of marginal bone loss were 1.23 mm (external) and 0.72 mm (internal) (P<0.001) after 1 year of loading, and 1.20 mm and 1.00 mm for external and internal abutment connections, respectively (P=0.137) after 5 years. Implant length (longer, P=0.018), smoking status (heavy, P=0.001), and prosthetic type (bridge, P=0.004) were associated with significantly greater marginal bone loss, and the use of screw-cement-retained prosthesis was significantly associated (P=0.027) with less marginal bone loss. Conclusions: There was no significant difference in the cumulative survival rate between implants with external and internal abutment connections. After 1 year of loading, marginal bone loss was greater around the implants with an external abutment connection. However, no significant difference between the external and internal connection groups was found after 5 years. Both types of abutment connections are viable treatment options for the reconstruction of partially edentulous ridges.