• Journal of Korean Dental Science
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• v.3 no.1
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• pp.11-16
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• 2010

Objective : This prospective study sought to verify the stability of three types of short implants measuring 7mm or less. Materials and methods : Implants measuring 7mm or less were placed in patients at multicenter dental clinics in Korea, China, Taiwan, and Singapore. Initial stability, intraoperative and postoperative complications, crestal bone loss, and survival rate of the implant were prospectively evaluated. Results : The primary stability of a 6-mm implant was lower than that of a 7-mm implant. The marginal bone loss of short implants measuring less than 7mm was minimal. Complications such as wound dehiscence, implant mobility, and peri-implant mucositis developed, and these were associated with initial implant failure. The short-term survival rate of 6-mm implant was 93.7%, and that of 7-mm implant, 96.6%. Conclusion : Short implant for the mandible with insufficient height for the residual ridge can be selectively used. Poor primary stability and wound dehiscence can cause osseointegration failure and alveolar bone loss.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.38 no.1
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• pp.2-8
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• 2012

Introduction: Auto-tooth bone graft material consists of 55% inorganic hydroxyapatite (HA) and 45% organic substances. Inorganic HA possesses properties of bone in terms of the combining and dissociating of calcium and phosphate. The organic substances include bone morphogenetic protein and proteins which have osteoinduction capacity, as well as the type I collagen identical to that found in alveolar bone. Auto-tooth bone graft material is useful as it supports excellent bone regeneration capacity and minimizes the possibility of foreign body reaction,genetic diseases and disease transmission. Materials and Methods: Implant placement combined with osteoinductive regeneration,preservation of extraction socket, maxillary sinus augmentation, and ridge augmentation using block type,powder type, and block+powder type autobone graft materialwere performed for 250 patients with alveolar bone defect and who visited the Department of Oral and Maxillofacial Surgery, College of Dentistry, Dankook University from September 2009 to August 2011. Results: Clinical assessment: Among the 250 patients of auto-tooth bone graft, clinical assessment was performed for 133 cases of implant placement. The average initial stabilization of placed implants was 74 implant stability quotient (ISQ). Radiological assessment: The average loss of crestal bone in the mandible as measured 6 months on the average after the application of prosthesis load was 0.29 mm, ranging from 0 mm to 3.0 mm. Histological assessment: In the histological assessment, formation of new bone, densified lamellated bone, trabecular bones, osteoblast, and planting fixtures were investigated. Conclusion: Based on these results, we concluded that auto-tooth bone graft material should be researched further as a good bone graft material with osteoconduction and osteoinduction capacities to replace autogenous bone, which has many limitations.

• Journal of Periodontal and Implant Science
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• v.39 no.3
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• pp.311-320
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• 2009

Purpose: The aim of the present study was to analyze 7-year cumulative survival rate (CSR, %) of dental implants in the controlled diabetic patients and to evaluate the influence of the position, diameter and length of fixture, bone quality, age, gender and the method of maxillary sinus elevation on the survival rate. Methods: The data of 342 placed implants in the 104 diabetic patients collected between 1995 and 2007 at the Department of Periodontology in Yonsei University Hospital were analyzed. Results: Seven-year CSR of the 342 dental implants in the 104 controlled diabetic patients was 96.5%. The survival rates of the placed implants according the position have no statistically significant difference. The survival rates according to the length or diameter of the fixtures have no statistically significant difference. The survival rates according to the bone quality were 100% (Type I), 97.1% (Type II), 97.7% (Type III) and 85.7%(Type IV). The difference between the survival rate of Type I, II and III and that of Type IV was statistically significant. The survival rates according to patient gender were 96.8% (male), 95.5% (female). The survival rates according to patient age were 100% (${\leq}59$), 93.8% (${\geq}60$). The survival rates according to the method of sinus elevation in the maxillary posterior area were 96.8% (without sinus elevation), 92.9% (lateral approach) and 89.8% (crestal approach). Conclusions: Dental implants can be used successfully in the controlled diabetic patients. In case of upper posterior region which has poor bone density and older patients, the implant treatment should be more properly planed, executed, and followed-up.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.17 no.1
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• pp.271-278
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• 1987

The purpose of the present study was to investigate associations between periapical and bitewing techniques by assessing the crestal alveolar bone. This article also reports the ability of these two techniques to correctly detect evidence of interproximal dental caries, and comparison between the interproximal overlapping of teeth. Bitewing and periapical radiographs were used from posterior quardants of 243 dental students in Seoul National University. The distance from cemento-enamel junction to the alveolar crest (CEJ-AC) was measured for each proximal surface from the distal of cuspid to the distal of second molar. Data were arranged according to the proximal surface examined, and bitewing and periapical measurements were compared using paired tests. The obtained results were as follows: 1. In maxilla, a significant t ratio with a P value of 0.05 or less reached for 100% and in mandible, reached for 94%. 2. The anatomic limitations imposed on periapical radiographic technique, most often result in somewhat foreshortened radiographic images. This situation would tend to be accentuated by the anatomical restrictions of the hard palate. 3. Consequently, since the significant differences frequently exist between measurements obtained from bitewing and periapical techniques, it is important to define which technique is used. 4. The number of the interproximal overlapping was the largest medial side of the maxillary second molar, while the smallest at the distal side of the mandibular second premolar. And the overall number of the interproximal overlapping was more (538) in the periapical technique than in the bitewing technique (372). 5. The interproximal dental carious lesions were detected more (74) on the bitewing films than on the periapical ones (23). The fact was resulted from the small number of interproximal overlapping and relative easi- ness of obtaining horizontal angulation in taking the bitewing radiographs.

• The Journal of Korean Academy of Prosthodontics
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• v.33 no.2
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• pp.241-268
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• 1995

Splint therapy, the immobilization of teeth, has been done for patient's masticatory comforts and an adjunctive aid in periodontal therapy. Mandibular premolars are frequently splinted in many distal extension removable partial denture cases. But splinting is an extensive restoration that may not be conservative of tooth structure and may prove to be quite costly to the patient. The two dimensional finite element analysis method was used to determine the magnitude and mode of distribution of the stresses of the periodontal ligament and supporting alveolar bone when abutments with different periodontal supports were splinted and distal-extension removable partial denture was subjected to different loading schemes. The results were as follows : 1. When abutments were splinted, stresses moved from apico-distal to apico-mesial of terminal abutment on a vertical force and from disto-alveolar crest to apex on a distally directed force. But stresses were generally diminished on a mesially directed force. 2. As vertical bone loss was proceeding, most of stresses were transmitted to residual ridge and the rest of stresses were concentrated on apex of distal abutment. But these apical stresses were minimized when abutments were splinted. 3. As mesially inclined bone loss was proceeding, it seemed to be dangerous that many stresses were concentrated on the distal alveolar crest, especially in the distally directed load case. Abutments splinting decreased the alveolar crestal stresses but not enough. 4. For all vertical stresses were effectively decreased on splinting, stresses were concentrated as highly on apico-mesial area of distal abutment in distally directed load cases as the distal inclination of bone level was severe. 5. The directions and magnitudes of abutment movements were decreased with teeth splinting.

• Journal of Periodontal and Implant Science
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• v.33 no.4
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• pp.705-715
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• 2003

Procedures for treatment of molar furcation invasion defects range from open flap debridement, apically repositioned flap surgery, hemisection, tunneling or extraction, to regenerative therapies using bone grafting or guided tissue regenerative therapy, or a combination of both. Several clinical evaluations using regenerative techniques have reported the potential for osseous repair of treated furcation invasions. Regenerative treatment of maxillary molars are more difficult due to the multiple root anatomy and multiple furcation entrances therefore, purpose of this study was to evaluated histologically compomer and Ketac Silver as a barrier in the treatment of a bi-furcated maxillary premolar. Five adult beagle dogs were used in this experiment. With intrasulcular and crestal incision, mucoperiostcal flap was elevated. Following decortication with 1/2 high speed round bur, furcation defect was made on maxillary premolar. 2 month later one premolar was filled with compomer and the other premolar was filled with Ketac Silver. After 4, 8 weeks, the animals were sacrificed by vascular perfusion. Tissue block was excised including the tooth and prepared for light microscope with H-E staining. Results were as follows. 1. Compomer & Ketac Silver restoration were encapsulated fine connective tissue. 2. In 4 weeks, compomer & Ketac Silver restoration slightly infiltrated inflammatory cells but not disturb the new bone or new cementum formation. 3. In 8 weeks, compomer & Ketac Silver restoration were less infiltrated iflammatory cell and encapsulated fine connective tissue. 4. Therefore, compomer & Ketac Silver filling to the grade III maxillary furcations with multiple root anatomy and multiple furcation entrances is possible clinical method and this technique is useful method for maxillary furcation involvement but it is thought that periodic maintenance should be needed

• Journal of Yeungnam Medical Science
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• v.20 no.2
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• pp.169-176
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• 2003

Background: Although dental implantation has become widespread and acceptable treatment for dental prosthodontics, maxillary posterior jaw region is often complicated by the pneumatization of the maxillary sinus and physiological resorption of the alveolar bone. When this occurs, the residual bone between the floor of the sinus and the crestal ridge is inadequate for the placement of implants. The sinus elevation procedure provides a way to increase the amount of available bone and to allow the placement of longer implants. Materials & methods: We studied 11 patients requiring the implant placements and the maxillary sinus elevation simultaneously from 1996 to 2003 in our clinic. Nine patients were males and two patients were females, aged from 39 to 72(mean=51.6). Four patients had medical compromised states; angina pectoris, diabetes, hypertension, hepatitis. Patients didn't show any pathologic findings clinically or radiographically. We studied the success and survival rate of implants, factors increasing the osseointegrating capacity of implants. Results: The success rate of osseointegration of implants was 93%. At least 6 months after loading on implants, the survival rate of implants was 78.5%. Autogenous bone graft and adequate residual bone height(>6mm) increased survival rate of implants. Conclusion: Successful implant placement with maxillary sinus elevation mainly depends on sufficient residual bone height, healthy maxillary sinus, autogenous bone graft.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.39 no.4
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• pp.156-160
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• 2013

Objectives: Interest in bone graft material has increased with regard to restoration in cases of bone defect around the implant. Autogenous tooth bone graft material was developed and commercialized in 2008. In this study, we evaluated the results of vertical and horizontal ridge augmentation with autogenous tooth bone graft material. Materials and Methods: This study targeted patients who had vertical or horizontal ridge augmentation using AutoBT from March 2009 to April 2010. We evaluated the age and gender of the subject patients, implant stability, adjunctive surgery, additional bone graft material and barrier membrane, post-operative complication, implant survival rate, and crestal bone loss. Results: We performed vertical and horizontal ridge augmentation using powder- or block-type autogenous tooth bone graft material, and implant placement was performed on nine patients (male: 7, female: 2). The average age of patients was $49.88{\pm}12.98$ years, and the post-operative follow-up period was $35{\pm}5.31$ months. Post-operative complications included wound dehiscence (one case), hematoma (one case), and implant osseointegration failure (one case; survival rate: 96%); however, there were no complications related to bone graft material, such as infection. Average marginal bone loss after one-year loading was $0.12{\pm}0.19$ mm. Therefore, excellent clinical results can be said to have been obtained. Conclusion: Excellent clinical results can be said to have been obtained with vertical and horizontal ridge augmentation using autogenous tooth bone graft material.

• Journal of Periodontal and Implant Science
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• v.41 no.5
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• pp.211-217
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• 2011

Purpose: The marginal bone levels around implants following restoration are used as a reference for evaluating implant success and survival. Two design concepts that can reduce crestal bone resorption are the microthread and platform-switching concepts. The aims of this study were to analyze the placement of microthreaded and platform-switched implants and their short-term survival rate, as well as the level of bone around the implants. Methods: The subjects of this study were 27 patients (79 implants) undergoing treatment with microthreaded and platform-switched implants between October 2008 and July 2009 in the Dental Hospital of Yonsei University Department of Periodon-tology. The patients received follow-up care more than 6 months after the final setting of the prosthesis, at which time periapical radiographs were taken. The marginal bone level was measured from the reference point to the lowest observed point of contact between the marginal bone and the fixture. Comparisons were made between radiographs taken at the time of fixture installation and those taken at the follow-up visit. Results: During the study period (average of 11.8 months after fixture installation and 7.4 months after the prosthesis delivery), the short-term survival rate of microthreaded and platform-switched implants was 100% and the marginal bone loss around implants was $0.16{\pm}0.08$ mm, the latter of which is lower than the previously reported values. Conclusions: This short-term clinical study has demonstrated the successful survival rates of a microthread and platform-switched implant system, and that this system is associated with reduced marginal bone loss.

• The Journal of Korean Academy of Prosthodontics
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• v.58 no.4
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• pp.306-312
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• 2020

Purpose: The aim of this study was to compare radiographic outcomes around narrow-diameter implants placed using guided flapless surgery at longer than 6 month post-placement. Materials and methods: A total of 12 implants were assessed in 12 patients for the sites where 0.5 - 1.5 mm labial bone was covering the implants, using CBCT. Results: A statistically significant preservation of crestal bone was observed in the narrow-diameter implants. Conclusion: Guided flapless implant surgery may be important in preventing bone loss around the narrow-diameter implants that are placed in narrow alveolar ridges.