• The korean journal of orthodontics
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• v.46 no.5
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• pp.310-322
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• 2016

Objective: The aim of this study was to determine the optimal loading conditions for pure intrusion of the six maxillary anterior teeth with miniscrews according to alveolar bone loss. Methods: A three-dimensional finite element model was created for a segment of the six anterior teeth, and the positions of the miniscrews and hooks were varied after setting the alveolar bone loss to 0, 2, or 4 mm. Under 100 g of intrusive force, initial displacement of the individual teeth in three directions and the degree of labial tilting were measured. Results: The degree of labial tilting increased with reduced alveolar bone height under the same load. When a miniscrew was inserted between the two central incisors, the amounts of medial-lateral and anterior-posterior displacement of the central incisor were significantly greater than in the other conditions. When the miniscrews were inserted distally to the canines and an intrusion force was applied distal to the lateral incisors, the degree of labial tilting and the amounts of displacement of the six anterior teeth were the lowest, and the maximum von Mises stress was distributed evenly across all the teeth, regardless of the bone loss. Conclusions: Initial tooth displacement similar to pure intrusion of the six maxillary anterior teeth was induced when miniscrews were inserted distal to the maxillary canines and an intrusion force was applied distal to the lateral incisors. In this condition, the maximum von Mises stresses were relatively evenly distributed across all the teeth, regardless of the bone loss.

• The Journal of Korean Academy of Prosthodontics
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• v.51 no.3
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• pp.183-189
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• 2013

Purpose: The aim of this study was to evaluate clinical outcomes of implant supported fixed-hybrid prostheses (FHP) in the fully edentulous arches. Materials and methods: Patients in this retrospective study were restored with fixed-hybrid prostheses supported by 4 to 6 implants and functioned more than 1 year of loading. Outcome measures were marginal bone change of implant related with sex, anatomical location (maxilla vs. mandible), opposing teeth, loading time of patients, tilting of posterior implant by Mann- Whitney U test and cantilever length of superstructure by regression analysis, and complication rates. Significance level was set P<.05. Results: A total number of 84 implants (16 restorations) placed in 16 patients were observed for 28 months and mean marginal bone loss was $0.53{\pm}0.39mm$. There were no differences of marginal bone loss according to sex, anatomical location (maxilla vs. mandible), opposing teeth, loading time of patients (P>.05), and cantilever length was not significantly related with a marginal bone loss of implant next to cantilever (P>.05). Complication was shown in 11 patients and veneer fracture and dislodging of artificial teeth were most prevalent. Conclusion: Within the limitations of this study, although marginal bone loss of FHP was very little, complication rates were high. Irrespective of tilting of most posterior implants, marginal bone loss of most posterior implants next to cantilever was less than those of the other implants positioned anteriorly. Cantilever length (<17 mm) did not affect a marginal bone loss of most posterior implants.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.39 no.4
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• pp.161-167
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• 2013

Objectives: The objective of this study is compare the rate of marginal bone resorption around hydroxyapatite-coated implants given different loading times in order to evaluate their stability. Materials and Methods: The study was conducted retrospectively for one year, targeting 41 patients whose treatment areas were the posterior maxilla and the mandible. Osstem TS III HA (Osstem Implant Co., Busan, Korea) and Zimmer TSV-HA (Zimmer Dental, Carlsbad, CA, USA), which employ the new hydroxyapatite coating technique, were used. The patients were divided into two groups - immediate and delayed loading - and the bone level at the time of loading commencement and after one year of loading was measured using periapical radiography. Differences between the groups were evaluated using Mann-Whitney (${\alpha}$=0.05). Results: For all patients as a single group, the survival rate of the implants was 100%, and the mean marginal bone loss was $0.26{\pm}0.59mm$. In comparison of the differences by loading, mean marginal bone loss of $0.32{\pm}0.69mm$ was recorded for the immediate loading group whereas the delayed loading group had mean marginal bone loss of $0.16{\pm}0.42mm$. However, the difference was not significant (P>0.05). Conclusion: Within the limited observation period of one year, predictable survival rates can be expected when using immediately loaded hydroxyapatite-coated implants.

• Journal of Periodontal and Implant Science
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• v.48 no.2
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• pp.103-113
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• 2018

Purpose: The purpose of this retrospective study with 4-12 years of follow-up was to compare the marginal bone loss (MBL) between external-connection (EC) and internal-connection (IC) dental implants in posterior areas without periodontal or peri-implant disease on the adjacent teeth or implants. Additional factors influencing MBL were also evaluated. Methods: This retrospective study was performed using dental records and radiographic data obtained from patients who had undergone dental implant treatment in the posterior area from March 2006 to March 2007. All the implants that were included had follow-up periods of more than 4 years after loading and satisfied the implant success criteria, without any peri-implant or periodontal disease on the adjacent implants or teeth. They were divided into 2 groups: EC and IC. Subgroup comparisons were conducted according to splinting and the use of cement in the restorations. A statistical analysis was performed using the Mann-Whitney U test for comparisons between 2 groups and the Kruskal-Wallis test for comparisons among more than 2 groups. Results: A total of 355 implants in 170 patients (206 EC and 149 IC) fulfilled the inclusion criteria and were analyzed in this study. The mean MBL was 0.47 mm and 0.15 mm in the EC and IC implants, respectively, which was a statistically significant difference (P<0.001). Comparisons according to splinting (MBL of single implants: 0.34 mm, MBL of splinted implants: 0.31 mm, P=0.676) and cement use (MBL of cemented implants: 0.27 mm, MBL of non-cemented implants: 0.35 mm, P=0.178) showed no statistically significant differences in MBL, regardless of the implant connection type. Conclusions: IC implants showed a more favorable bone response regarding MBL in posterior areas without peri-implantitis or periodontal disease.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.24 no.1
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• pp.95-105
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• 1994

The aim of this study was to evaluate the clinical, radiographic and histopathologic features of 23 cases of solitary bone cyst by means of the analysis of radiographs and biopsy specimens in 23 persons visited the Department of Oral and Maxillofacial Radiology, School of Dentistry, Kyung Hee University and Chunbuk National University. The obtained results were as follows; 1. The incidence of solitary bone cyst was almost equal in males(52.2%) and in females(47.8%) and the prevalent age of the solitary bone cyst were the second decade(47.8%) and the third decade (21.7%). 2. In the signs and symptoms of solitary bone cyst, pain or tenderness revealed in 17.4%, swelling revealed in 13.0%, pain and swelling revealed in 21.7%, paresthesia revealed in 4.4% and 43.5% were asymptom and the tooth vitality involved in the solitary bone cyst, 76.5% were positive and 23.5% were either positive or negative. 3. In the location of the solitary bone cyst, 47.8% present posterior region, 21.7% present anterior region, 21.6% present anterior and posterior region, 4.4% present condylar process area. 4. In the hyperostotic border of the solitary bone cyst, 47.8% were seen entirely, 21.8% were seen partialy, and 30.4% were not seen. 5. In the change of tooth, 59.1% were intact, 18.2% were loss of the alveolar lamina dura, 13.6% were root resorption 4.55% were tooth displacement, 4.55% were root resorption and tooth displacement. 6. In the change of cortical bone of the solitary bone cyst, 39.1% were intact and 60.9% were thinning and expansion of cortical bone. 7. In the histopathologic findings of 9 cases, 33.3% were thin connective tissue wall, 11.1% were thickened myxofibromatous wall, 55.6% were thickened myxofibromatous wall with dysplastic bone formation.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.2
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• pp.125-136
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• 2008

Statement of problem: Since the concept of osseointegration in dental implants was introduced by $Br{{\aa}}nemark$ et al, high long-term success rates have been achieved. Though the use of dental implants have increased dramatically, there are few studies on domestic implants with clinical and objective long-term data. Purpose: The aim of this retrospective study was to provide long-term data on the $Neoplan^{(R)}$ implant, which features a sandblasted and acid-etched surface and external connection. Material and methods: 96 $Neoplan^{(R)}$ implants placed in 25 patients in Yonsei University Hospital were examined to determine the effect of the factors on marginal bone loss, through clinical and radiographic results during 18 to 57 month period. Results: 1. Out of a total of 96 implants placed in 25 patients, two fixtures were lost, resulting in 97.9% of cumulative survival rate. 2. Throughout the study period, the survival rates were 96.8% in the maxilla and 98.5% in the mandible. The survival rates were 97.6% in the posterior regions and 100% in the anterior regions. 3. The mean bone loss for the first year after prosthesis placement and the mean annual bone loss after the first year for men were significantly higher than that of women (P<0.05). 4. The group of partial edentulism with no posterior teeth distal to the implant prosthesis showed significantly more bone loss compared to the group of partial edentulism with presence of posterior teeth distal to the implant prosthesis in terms of mean bone loss for the first year and after the first year (P<0.05). 5. The mean annual bone loss after the first year was more pronounced in posterior regions compared to anterior regions (P<0.05). 6. No significant difference in marginal bone loss was found in the following factors: jaws, type of prostheses, type of opposing dentition, and submerged /non-submerged implants (P<0.05). Conclusion: On the basis of these results, the factors influencing marginal bone loss were gender, type of edentulism, and location in the arch, while the factors such as arch, type of prostheses, type of opposing dentition, submerged / non- submerged implants had no significant effect on bone loss. In the present study, the cumulative survival rate of the $Neoplan^{(R)}$ implant with a sandblasted and acid-etched surface was 97.9% up to a maximum 57-month period. Further long-term investigations for this type of implant system and evaluation of other various domestic implant systems are needed in future studies.

• Journal of Periodontal and Implant Science
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• v.40 no.2
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• pp.76-85
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• 2010

Purpose: This study aimed to evaluate the effectiveness of the modified sinus floor elevation technique described hereafter as a "hybrid technique," in 11 patients with severely resorbed posterior maxillae. Methods: Eleven patients who received 22 implants in the maxillary premolar and molar areas by the hybrid technique were enrolled in this study. A slot-shaped osteotomy for access was prepared on the lateral wall along the lower border of the sinus floor. The Schneiderian membrane was fully reflected through the lateral slot. Following drilling with the membrane protected by a periosteal elevator, the bone was grafted. All implants were placed simultaneously with sinus augmentation. The cumulative success rate was calculated and clinical parameters were recorded. Radiographic measurements were performed. Results: All implants were well maintained at last follow up (cumulative success rate=100%). The mean residual bone height, augmented bone height, crown-to-implant ratio, and marginal bone loss were $4.1{\pm}1.64mm$, $8.76{\pm}1.77mm$, $1.21{\pm}0.34mm$, and $0.34{\pm}0.72mm$, respectively. Conclusions: Simultaneous implant placement with sinus augmentation by hybrid technique showed successful clinical results over a 2-year observation period and may be a reliable modality for reconstruction of a severely resorbed posterior maxilla.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.4
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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.

• The Journal of Advanced Prosthodontics
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• v.4 no.1
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• pp.18-23
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• 2012

PURPOSE. The purpose of this prospective study was to evaluate the effect of early loading on survival rate or clinical parameter of anodic oxidized implants during the 12- month postloading period. MATERIALS AND METHODS. Total 69 implants were placed in 42 patients. Anodic oxidized implants (GS II, Osstem Cor., Busan, Korea) placed on the posterior mandibles were divided into two groups, according to their prosthetic loading times: test group (2 to 6 weeks), and control group (3 to 4 months). The implant survival rates were determined during oneyear postloading period and analyzed by Kaplan-Meier method. The radiographic peri-implant bone loss and periodontal parameters were also evaluated and statistically analyzed by unpaired t-test. RESULTS. Total 69 implants were placed in 42 patients. The cumulative postloading implant survival rates were 88.89% in test group, compared to 100% in control group (P<.05). Periimplant marginal bone loss (T: $0.27{\pm}0.54$ mm, C: $0.40{\pm}0.55$ mm) and periodontal parameters showed no significant difference between the groups (P>.05). CONCLUSION. Within the limitation of the present study, implant survival was affected by early loading on the anodic oxidized implants placed on posterior mandibles during one-year follow-up. Early implant loading did not influence peri-implant marginal bone loss, and periodontal parameters.

• The Journal of Korean Academy of Prosthodontics
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• v.42 no.4
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• pp.458-470
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• 2004

Statement of problem: Br${\aa}$nemark or ITI are two currently most widely used implant systems but with contrasting design, surgical and restoration methods. Purpose: The purpose of this study was to compare changes and its statistical significance in bone height and shape which may rise due to the differences between two implant systems. Also to analyse the effect of inter-implant distance on annual bone height changes. Material & Method: Those patients who were treated with two or more of either Br${\aa}$nemark or ITI implants at posterior mandibular area at Yonsei University Dental Hospital, Implant Clinic were selected. At annual examination appointments, standardised radiographs using parallel technique were taken. Marginal bone and inter-implant crestal bone changes were measured and following results were obtained. Results: 1) When ITI and Br${\aa}$nemark system were compared, both annual marginal and inter-implant crestal bone height changes in ITI system in the first two years were smaller than Br${\aa}$nemark and they were statistically significant. On the third year, however, there was no statistical difference between two implant systems on their annual bone level changes (p>0.05). 2) The Marginal and inter-implant crestal bone changes were compared when inter-implant distance was less than 4mm. Statistically significant bone level changes were noted on the first year only for ITI implants but in the first and second year for Br${\aa}$nemark implants (p>0.05). 3) When comparing angulation changes between marginal bone and implant fixture, ITI system had smaller angulation changes but the annual changes were not statistically significant (p>0.05). Conclusion: Within the limitation of this study, it could be concluded that Br${\aa}$nemark implant systems had more changes in marginal and inter-implant crestal bone level in the first and second year after loading with statistical significance. Further studies are recommended to see the effects of these bone loss during the first and second year after loading on the long term prognosis of Br${\aa}$nemark Implants.