• The Journal of Korean Academy of Prosthodontics
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• v.30 no.4
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• pp.541-564
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• 1992

The purpose of this experiment was to study the effect of implantation of the dense hydroxyapatite (HA) granules$(Apaceram^{(R)})$ in the fresh extraction sockets on the residual ridge resorption in normal and induced diabetic rabbits. Sixty-four white rabbits, weighing 3.0kg, were utilized in this study and they were divided into four group : group 1-sixteen normal rabbits without filling HA granules, group 2-sixteen normal rabbits with filling HA granules, group 3-sixteen diabetic rabbits without filling HA granules, group 4-sixteen diabetic rabbits with filling HA granules. HA granules were filled immediately after extraction in the extraction sockets of the mandibular left 1st, 2nd, and 3rd molar in group 2 and 4, and no HA granules were filled in group 1 and 3. The calculation of residual ridge resoption was done at 4th week, 8th week, 12th week, and 16th week after surgery, and histologic examination was performed to study healing process at 2nd week, 4th week, 8th week, and 16th week after surgery. The results were as follows : 1. The amount of residual ridge resorption was largest in group 3, and smallest in group 2 in every interval. There was no statistically significant difference between group 1 and 4. 2. In all groups, the amount of residual ridge resorption was high until 4th week after surgery, but the rate of residual ridge resolution slowly decreased after 4th week 3. There was more active healing process in group 1 and 2 than in group 2 and 4. 4. According to filling of HA granules, there was no difference in the amount of new bone formation, but direct contact could be observed between newly formed bone and HA granules in group 2 and 4. 5. Group 1 and 3 showed marked bone resorption and adipose marrow from 8th-16th week after surgery, but group 2 and 4 did not show maeked bone resolution, and showed fibrous tissue and a little adipose tissue among trabeculae from 8th week.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.3
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• pp.249-257
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• 2008

The authors performed the clinical and radiographic evaluation in the 29 patients with sinus bone graft and $Osstem^{(R)}$ implant placement between Sep 2003 and Jan 2006 and got the following results. 1. Fifteen complications developed in the 13 patients. Intraoperative sinus membrane perforation and postoperative maxillary sinusitis developed frequently. 2. The mean preoperative residual alveolar bone height was 4.5 mm, postoperative height 18.5 mm, height 1 year after operation 16.9 mm. 3. Three primary osseointegration failures(3.7%) developed in 3 patients. 4. The survival rate of prosthodontics was 100% at the final follow up. The mean marginal bone resorption around the implants was 0.69 mm 1 year after prosthodontic loading. Marginal bone resorption more than 1.5 mm developed in nine implants and the success rate was 88%.

• Journal of Periodontal and Implant Science
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• v.38 no.2
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• pp.225-230
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• 2008

Purpose: Many clinical studies have reported that higher success rates are achieved with teeth that have immature roots than other autotransplanted teeth that have more immature root. However, based on date published recently, the success rate of autotransplantation of teeth with complete root formation was higher. The purpose of this study was to examine the long term(2 to 6 years follow-up) success rate of autotransplantation of third molar with complete root formation and to discuss some conditions and prerequisites for success. Materials and Methods: 26 sites of 24 patients aged 26 to 55 (mean age 40.8) were autotransplanted with third molars with complete root formation. These cases were followed for 2 to 6 years after surgery. The success criteria included (1) no discomfort during functioning (2) absence of progressive root resorption and alveolar bone resorption. Result: Of 26 teeth 5 teeth were failed, therefore success rate is 81%(21/26 teeth). The results suggested that higher success rate is acquired from (1) extraction socket due to dental caries (2) mandibular recipient site (3) patient younger than 40 years old. Autotransplantation of third molar to replace molars with advanced periodontal disease also showed considerably high success rate(84%). Conclusion: With appropriate case selection, autotransplantation of third molar with complete root formation remains a viable alternative for replacing a missing molar tooth.

• Korean Journal of Agricultural and Forest Meteorology
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• v.21 no.3
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• pp.208-220
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• 2019

The seasonality of leaf fall has important implications for understanding the response of trees' phenology to climate change. In this study, we quantified the leaf fall pattern with a model to estimate the timing and speed of leaf litter according to species and considered the nutrient use strategy of canopy species. In the autumns of 2015 and 2016, leaf litter was collected periodically using 36 litter-traps from the deciduous forests in Gwangneung and sorted by species. The seasonal leaf fall pattern was estimated using the non-linear regression model of Dixon. Additionally, the resorption rate was calculated by analyzing the nitrogen concentration of the leaf litter at each collection time. The leaf litter generally began in early October and ended in mid-November depending on the species. At the peak time (T50) of leaf fall, on average, Carpinus laxiflora was first, and Quercus serrata was last. The rate of leaf fall was fastest (18.6 days) for Sorbus alnifolia in 2016 and slowest (40.8 days) for C. cordata in 2015. The nitrogen resorption rates at T50 were 0.45% for Q. serrata and 0.48% for C. laxiflora, and the resorption rate in 2015 with less precipitation was higher than in 2016. Since falling of leaf litter is affected by environmental factors such as temperature, precipitation, photoperiod, and $CO_2$ during the period attached foliage, the leaf fall pattern and nitrogen resorption differed year by year depending on the species. If we quantify the fall phenomena of deciduous trees and analyze them according to various conditions, we can predict whether the changes in leaf fall timing and speed due to climate change will prolong or shorten the growth period of trees. In addition, it may be possible to consider how this affects their nutrient use strategy.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.3
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• pp.176-183
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• 2011

Introduction: Very high aggressiveness and recurrence are important clinical characteristics of ameloblastoma compared to the other benign tumors. Therefore, an accurate diagnosis and treatment plan is important. This study examined the association of the clinical findings and recurrence based on the radiological findings of ameloblastoma. In recurrent cases, these results are expected to help in the diagnosis and treatment of ameloblastoma to examine the relevance with the clinical characteristics and radiological features. Materials and Methods: For a clinical (gender, age) and radiological (location, internal pattern, size, perforation, border pattern, impacted tooth, root resorption) evaluation, this study examined 156 cases of 147 patients diagnosed with ameloblastoma, who had been treated and in most cases regularly checked at the department of oral and maxillofacial surgery, Kyungpook National University Hospital, between January 1993 and December 2009. For a recurrent rate evaluation, a more than 3 years follow-up period is needed. Accordingly, 116 patients diagnosed with ameloblastoma between January 1994 and December 2007 were investigated. Results: The recurrence rate in all cases was 6.1% but was 7.8% in cases with follow-up periods more than 3 years. The male-to-female ratio was 3:2, showing a slight male predilection. Ameloblastoma had a peak occurrence in the second decade of life followed by the fourth decade of life. The mandibular angle area is the most frequent site of ameloblastoma (50.8%) in the jaws. Six cases of unilocular (7.8%) and 3 cases of multilocular (7.7%) ameloblastomas recurred. Seven cases of smooth (10%) and 2 cases of irregular (4.3%) ameloblastomas recurred. No cases of ameloblastomas without perforation of the cortical bone (0%) and 9 cases with a perforation of cortical bone (11.1%) recurred. Four cases of the ameloblastomas with impacted teeth (11.4%) and 5 cases of ameloblastomas without impacted tooth (6.2%) recurred. Seven cases of ameloblastomas with root resorption (10.9%) and 2 cases of ameloblastomas without root resorption (3.8%) recurred. Conclusion: A multiple smooth margin, unilocular ameloblastoma with an impacted tooth, root resorption tends to recur more easily. Therefore, they need to be treated more carefully and require a a longer follow-up.

• The Journal of the Korean dental association
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• v.48 no.1
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• pp.45-55
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• 2010

Purpose: The aim of this study was to evaluate 1 year cumulative survival rate of implants placed on augmented sinus using Osteon$^{(R)}$, bone graft material and to assess height of the grafted material radiographically. Material and Methods: 10 maxillary sinuses were augmented in 10 patients and 25 implant fixtures were installed simultaneously or after 6 months healing period. The height of the sinus graft material was measured using panoramic images immediately after augmentation and up to 19 months subsequently. Changes in the height of the sinus graft material were calculated with respect to implant length and original sinus wall height. Results: The cumulative survival rate was 100% in all 25 implants. Additionally, normal healing process without any complication was observed in all patients. The mean crown/Implant ratio was 1.25. The mean marginal bone loss was 0.95mm and the mean resorption rate of Osteon$^{(R)}$ was 0.05mm/month. The fastest resorption site of Osteon$^{(R)}$ is the first molar area. The grafted material was well maintained in sinus and decreased slightly over 1 year. Conclusion: In conclusion, It can be suggested that Osteon$^{(R)}$ may have predictable result when it was used as a grafting material for sinus floor augmentation.

• Journal of Society of Preventive Korean Medicine
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• v.14 no.2
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• pp.91-104
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• 2010

The experiments were undertaken to evaluate the effects of herbal medicine, Bojungiggitang and Gwibitang in pregnant rats and their fetuses. Female Sprague-Dawley rats were orally administered with the Bojungiggitang and Gwibitang at dose of 5ml/kg/day for 20 days. Pregnant rats were sacrificed at 20th day of gestation, and the internal and reproductive organs. Approximately live fetuses in the 20th day of gestation were randomly selected and fixed in 95% ethanol. To observe skeletal malformations, fetuses were stained with alcian blue and alizarin red S. Maternal body weights of Bojungiggitang and Gwibitang treated group has a tendency to increase compared to that of control group. There were no significant differences in internal and reproductive organs. There were no significant changes between two groups in blood chemistry and hematological values. There were no significant changes in number of corpus luteum, implantation and live fetuses. But Bojungiggitang and Gwibitang administered group showed higher implantation rate than the control group. Also, Bojungiggitang and Gwibitang administered groups showed lower early resorption rate than the control group. And Gwibitang had the higher value in all the other groups in all items. From the sex ratio, the number of females were larger than the number of males in the control group, and more males than females in Gwibitang administered group. Neonatal body weight and the number of fetus of Bojungiggitang and Gwibitang group were higher than that of control group. The fetuses of dams treated with Bojungiggitang and Gwibitang did not show external malformation. Vertebral and sternal variations were observed in Bojungiggitang and Gwibitang administered group compared to the control group. Those variations were insignificant. There were no significant changes in number of ribs, cervical, thoracic, lumbar, sacral and caudal vertebras. From these results, it can be concluded that Bojungiggitang and Gwibitang showed no toxic effects on maternal body weight and the number of live fetuses. There were no significant changes in organ weight, hematological data, and reproductive organs. Although skeletal variations were shown in vertebra and sternum, Bojungiggitang, Gwibitang were shown insignificant changes in bone malformation.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.29 no.3
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• pp.217-226
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• 2007

Purpose: Distraction osteogenesis is considered to take favorable effect on the TMJ and be beneficial to prevent the relapse after the mandibular advancement of Class II malocclusion patient. This is the report with literature review on the mandibular advancement in the patients showing preoperative condylar resorption and who need larger amount of advancement. Patients and method: Distraction osteogenesis using intraoral device was performed for three mandibular hypoplasia patients (one male and two females). All patients were adult over 18 years old. The patients showed condylar bony resorption preoperatively. The distraction was performed intraorally with modified SSRO. After 7 days of latency period, activation was performed at the rate of 1.0 mm/day with twice turn. The devices were removed after 4-8 month consolidation period. Results: Total advancement of mandible was average 13 mm. One patient showed openbite immediately after removal of distraction device. It took long time to guide the openbite with elastics. The comparison between cephalometries immediately after device removal and postoperative six month revealed average 3.4 mm relapse. This means that mandibular advancement with distraction osteogenesis needs overcorrection and elastic rehabilitation even after enough consolidation periods. Conclusion: Larger amount of mandibular advancement could be achieved with distraction osteogenesis in severe mandibular hypoplasia with condylar resorption. However, some relapse was found during the follow-up period and the over correction is considered to be needed. The effect of distraction osteogenesis seems to be investigated with long-term follow-up.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.41
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• pp.36.1-36.8
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• 2019

Background: This study aims to examine the outcome of simultaneous maxillary sinus lifting, bone grafting, and vertical ridge augmentation through retrospective studies. Methods: From 2005 to 2010, patients with exhibited severe alveolar bone loss received simultaneous sinus lifting, bone grafting, and vertical ridge augmentations were selected. Fifteen patients who visited in Seoul National University Bundang Hospital were analyzed according to clinical records and radiography. Postoperative complications; success and survival rate of implants; complications of prosthesis; implant stability quotient (ISQ); vertical resorption of grafted bone after 1, 2, and 3 years after surgery; and final observation and marginal bone loss were evaluated. Results: The average age of the patients was 54.2 years. Among the 33 implants, six failed to survive and succeed, resulting in an 81.8% survival rate and an 81.8% success rate. Postoperative complications were characterized by eight cases of ecchymosis, four cases of exposure of the titanium mesh or membrane, three cases of periimplantitis, three cases of hematoma, two cases of sinusitis, two cases of fixture fracture, one case of bleeding, one case of numbness, one case of trismus, and one case of fixture loss. Prosthetic complications involved two instances of screw loosening, one case of abutment fracture, and one case of food impaction. Resorption of grafted bone material was 0.23 mm after 1 year, 0.47 mm after 2 years, 0.41 mm after 3 years, and 0.37 mm at the final observation. Loss of marginal bone was 0.12 mm after 1 year, and 0.20 mm at final observation. Conclusions: When sinus lifting, bone grafting, and vertical ridge augmentation were performed simultaneously, postoperative complications increased, and survival rates were lower. For positive long-term prognosis, it is recommended that a sufficient recovery period be needed before implant placement to ensure good bone formation, and implant placement be delayed.

• The Journal of the Korean dental association
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• v.46 no.4
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• pp.243-247
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• 2008

Purpose : Ridge expansion osteotomy (REO) has been introduced when it is necessary to expand narrow crestal ridge with simultaneous implant placement. This study has designed to evaluate the clinical availability of REO. Materials and methods : Subject were patients who had visited Seoul National University Bundang Hospital from July. 2003 to December, 2005 for implant placement using REO by one surgeon. Intraoperative and postoperative complication, failure of initial osseointegration and marginal bone resorption were estimated using electronic medical record and periapical radiography. Twenty?three patients, 8 males and 15 females, mean age 51, ranged 18 to 72, were treated for mean 26 months, ranged from 16 months to 46 months. Results : Mean diameter and length of implants placed at upper anterior, were 3.72mm and 13.32mm each other. Guided bone regeneration and ridge splitting were accompanied in this study. Five cases of cortical bone fracture, three cases of crestal bone loss more than 2mm, 2cases of gingival recession, and 2 cases of infection were noted, but there were no implants removed because of disintegration. Success rate of implant was 91.7%, even if survival rate of implant was 100%. In addition, there were no statistical significance between the success rate of REO and bone graft(p>0.05). Conclusion : Based on the results of the present study, it can be concluded that REO technique is reliable for implant placement at atrophic ridge with adequate height compared to bone graft and other osteotomies for ridge expansion, but care should be taken of esthetic problem such as gingival recession because of crestal bone resorption from trauma by osteotome.