• The Journal of Korean Academy of Prosthodontics
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• v.56 no.1
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• pp.40-49
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• 2018

It is reported that the causes of unaesthetic proportion of anterior teeth vary widely. Especially, when the unaesthetic tooth proportion of the mandibular incisors arises due to the wear of the anterior teeth accompanied by the compensation of the alveolar bone, it may cause serious functional and aesthetic problems. In such case, it should be considered that the evaluation of vertical dimension and tooth proportion as well as smile line, soft tissue and hard tissue morphology. And, increase of vertical dimension or clinical crown lengthening followed by prosthodontic restorations is needed to improve the interdental mesial/distal, width/length ratio considering the anterior guidance. This case report demonstrates functional and aesthetic improvements through systematic diagnosis and treatment procedures in a 48-year-old male patient with unaesthetic anterior teeth proportion because of tooth wear accompanied by the compensation of alveolar bone and defect of several central incisors due to chronic periodontitis.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.19 no.4
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• pp.367-376
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• 1997

The 234 patients who received treatment of midfacial fractures at the Department of Oral and Maxillofacial Surgery of Chonnam University Hospital from Jan. 1, 1992 to Dec. 31, 1996 were analyzed clinicostastically. Results obtained were as follows ; Male predominated over females by a ratio of 5.3 to 1. The frequently developing age groups were first 3rd (25%), 4th (21%) and the 2nd (18%) decade on succession. The peakest month was the August (16%), and May (11%), September (9%), October (9%). When it comes to the reasons for in-patients, traffic accident was predominant to 38%. In the 234 cases of midfacial fractures, zygomaticomaxillary complex fracture was the most by 37%. The most common with injury show that facial laceration marked by 49%, neurologic injury 24%, and mandibular fracture 20% each by each. About the time from injury onset to operation, 55% of cases were less than a week while the others (45%) more than a week. 3 plates were used for operation : 2 for zygoma or maxilla fracture and 3 for zygomatiomaxillary complex fracture. especially 4 for Le Fort I fracture, 5.5 for Le Fort I, II ; I, III ; II, III fracture, 7 for Le Fort I,II,III fracture were used. 20 patients (8%) appealed their complication and the most common was reported as infection. Above results suggest that early diagnosis and treatment of fracture site, systemic condition and associated injuries are necessary, and coorperative treatment with medical department should be performed.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.41
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• pp.27.1-27.9
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• 2019

Background: Implants are becoming the first choice of rehabilitation for tooth loss. Even though they have a high success rate, failures still occur for many reasons. The objective of this study is to analyze the reasons for recurring failure at the same site and the results of re-implantation. Methods: Thirteen patients (11 males and 2 females, mean age 60 ± 9.9 years) who experienced implant surgery failure at the same site (same tooth extraction area) two or more times in the Department of Oral and Maxillofacial Surgery, Seoul National University Bundang Hospital, between 2004 and 2017 were selected. The medical records on a type, sites, diameter, and length of implants; time and estimated cause of failure; and radiographs were reviewed. Data were collected and analyzed retrospectively, and the current statuses were evaluated. Results: A total of 14 implants experienced failure in the same site more than two times. Twelve implants were placed in the maxilla, while 2 implants were placed in the mandible. The maxillary molar area was the most common site of failure (57.1%), followed by the mandibular molar, anterior maxilla, and premolar areas (14.3% each). The first failure occurred most commonly after prosthetic treatment (35.7%) with an average period of failure of 3.8 months after loading. Ten cases were treated as immediate re-implantation, while the other 4 were delayed reimplantation after an average of 3.9 months. The second failure occurred most commonly after prosthetic treatment (42.9%), with an average of 31 months after loading; during the healing period (42.9%); and during the ongoing prosthetic period (14.3%). In 3 cases (21.4%), the treatment plan was altered to an implant bridge, while the other 11 cases underwent another implant placement procedure (78.6%). Finally, a total of 9 implants (64.3%) survived, with an average functioning period of 60 months. Conclusions: Implants can fail repeatedly at the same site due to overloading, infection, and other unspecified reasons. The age and sex of the patient and the location of implant placement seem to be associated with recurring failure. Type of implant, bone augmentation, and bone materials used are less relevant.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.13 no.2
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• pp.129-136
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• 1991

The fibrin sealant was first designed as an alternative to surgical suture for the purpose of surface-to-surface union especially in parenchymal organs like the liver, spleen and kidney. The clinical application of currently used fibrin sealant was first introduced in 1972. The fibrin sealant consists of principal two components; lyophilized human fibrinogen and bovine thrombin. The fibrinogen component also contains coagulation factor XIII. A solution of aprotinin, an inhibitor of fibrinolysis is used to dissolve the fibrinogen and to provide the first component, and a solution of calcium chloride is also used to provide the second component. From July to December in 1990, during 6 months, we used fibrin sealant in the 28 patients of 33 various cases, in the following ways; supportive application of fibrin sealant after free autogenouse nerve graft for the repair of inferior alveolar nerve, facial nerve or accessory nerve, treament of hemangioma or lymphangioma to thrombosize and lead to the tumor shrinking, skin grafting to stimulate the adhesion and tissue repair, bone grafting in the patients of cleft alveolus, mandibular reconstruction or orthognathic surgery to facilitate the knitting of bone chips, tissue adhesion after tumor resection, radical neck dissection or flap reconstructions, and supportive adhesion of external auditory cannal after TMJ surgery via postauricular approach. No adverse effects were observed, none of the patients developed hepatitis or other blood transmitted disease, and the wound healing were acceptable.

• The korean journal of orthodontics
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• v.37 no.2 s.121
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• pp.89-97
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• 2007

Objective: The purpose of this study was to measure the insertion torque of orthodontic miniscrews regarding changes in their shape, diameter, and length. Methods: Torque values were measured during continuous insertion of the miniscrews into solid rigid polyurethane foam, using a torque tester of driving motor type with a regular speed of 3 rpm. Orthodontic miniscrews (Biomaterials Korea, Seoul, Korea) of cylindrical type and taper type were used. Results: Increasing the length and diameter of the miniscrews increased the maximum insertion torque value in both cylindrical and taper type screws. Insertion torque was increased at the incomplete head of the cylindrical type screw, and at the tapered part of the taper type screw. The insertion torque value of miniscrews was influenced most by diameter, then shape and length. As a result, it was shown that the diameter of the screw had the most influence on insertion torque, and the taper type screw had a higher torque value than the cylindrical type screw. Conclusion: Therefore, a large diameter or taper type screw are adequate for areas of thin cortical bone with a large interdental space, and a small diameter or cylindrical type screw are adequate in the mandibular molar area or the midpalatal area having thick cortical bone.

• The Journal of Korean Academy of Prosthodontics
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• v.29 no.2
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• pp.285-294
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• 1991

The human temporomandibular joint as a ginglymoarthrodial one has much in common with the other synovial joints of the body, but it does possess an unique charachteristic in that it must accomodate the various occlusal relations of dentition during an end point of closure. For that reason, the movement of the condyle in the temporomandibular joint is susceptible to influences from the nature of occlusion. Undue loading to the temporomandibular joint can be applied on the occasion of premature contacts in centric relation, balancing side interferences, change of occlusal surfaces due to excessive attrition, loss of tooth. Such occlusal disharmonies in association with the systemic and emotional factors may give rise to the temporomandibular disorder. On the other hand, the changes of occlusal patterns in the growing body can also have an effect on the growth of the temporomandibular joint through the alterations of functional stresses. The purpose of this study was to observe histopathologic response of the temporomandibular joint in unilateral chewing on one side exclusively for 10 months. Three dogs showing normal masticatory function were chosen. One dog aged about 12 months was for control, two dogs for experimental specimens were about 12 and 18 months old respectively. For chewing on the left side only, unilateral lower right premolar and molar were extracted in two experimental specimens. And then three dogs were sacrificed 10 months later. Frontal histologic sectioning of joints were done for the observation of the effects of one-side chewing. 24 specimens from three dogs were obtained and fixed in 10% formalin and routinly processed with H-E staining for histologic examination. The light microscopic findings were interpretated as follows: 1. Experimental specimen 1 aged about 22 months: In comparison with control and right non-chewing side, the proliferative and hypertrophic zone were increased at the mesial and lateral part of left chewing side condyle. There was no change of the articular tissue of temporal bone. 2. Experimental specimen 2 aged about 28 months: The articular tissues of adult joint were observed. The differences between the chewing and non-chewing side were not seen in the articular tissues of condyle and temporal bone.

• 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 Korean Academy of Prosthodontics
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• v.43 no.1
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• pp.105-119
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• 2005

Statement of problem. As the effects of the various diameters of fixture and abutment screw on stress distribution was not yet examined, this study focused on the different design of single implant restoration using three dimensional finite element analysis. Purpose. This study was to compare five different fixture-abutment combinations for single implant supported restorations with different fixture and abutment screw diameters. Material of methods. The five kinds of finite element models were designed by 3 diameter fixtures ($\oslash$3.3, 3.75, 5.0 mm) with 3 different abutment screws $\oslash$1.5, 1.7, 2.0 mm). The crown for mandibular first molar was made using UCLA abutment according to Wheeler's anatomy. 244 N was applied at the central fossa with two different loading directions, vertically and obliquely (30$^{\circ}$) and at the buccal cusp vertically. Maximum von Mises stresses were recorded and compared in the supporting bone, crowns, fixtures, and abutment screws. Results. 1. The stresses in supporting bone and implant-abutment structure under oblique loading were greater than those under vertical or offset loading. The stresses under vertical loading were the least among 3 loading conditions regardless of the implant and abutment screw diameters. 2. The stresses in the narrow implants were greater than the wider implants. The narrow implant with narrow abutment screw showed highest stresses in the lingual crest, but the narrow implant with standard abutment screw showed highest stress in abutment screw. 3. The stresses of abutment screws were influenced by the diameter of fixtures and loading conditions. The wide implants showed least difference between two different abutment screw diameters. Conclusions. The wide implants showed lesser stresses than the narrow implants and affected least by the different abutment screw diameters. The narrow implants with standard abutment screw showed highest stresses in the lingual bony crest under oblique loading.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.4
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• pp.703-708
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• 2005

Cleidocranial Dysplasia(CCD) is a congenital disorder of skeletal and dental anomaly with an autosomal dominant mode of inheritance. CCD Shows a generalized defect in intramembranous bones, such as the skull, clavicles, and endochondral bones, such as the long bones and the remainder of the skeleton. The specific clinical feature of CCD is an aplasia & hypoplasia of one or both clavicles, frontal & parietal bone bossing, incomplete fontanels and sutures closure of cranial bone. Generally, relative mandibular prognathism is seen, because maxillar is underdeveloped. Dental anomalies of CCD are prolonged primary teeth, delayed eruption of the permanent teeth and multiple supernumerary teeth. Almost patients of CCD can not recognize their dental abnormality until the permanent teeth eruption was begining. So it is difficult to decide the proper timing of the treatment of patients of CCD. Pedodontists should understand the development of the dentition in CCD patient and start the treatment of CCD patient in proper time.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.4
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• pp.709-716
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• 2005

Patients with cleft tip and palate present severe maxillary hypoplasia due to scar of lip and palate, often accompanied by compromised mastication, speech abnormalities. Sometimes maxillary hypoplasia persist even though active orthodontic treatment was done. In theses cases, patients born with cleft lip and palate will be potential candidates for maxillary advancement with bone grafting after growth to correct the functional deformities and improve aesthetic facial proportions. But, maxillary advancement using standard surgical approaches has several limitations : increased relapse tendency after maxillary advancement, necessity of additional bone graft and mandibular setback surgery. Distraction osteogenesis is current treatment modality to overcome these limitations, thus has become popular for treatment of maxillary hypoplasia associated cleft lip and palate, craniosyntosis. Especially, rigid external distraction, contrary to internal device, has advantages : better vector control of osteotomized segment, effective traction of the bony segments, the ease of the application and removal the distraction device. This study showed that relatively successful result could be generated by using rigid external distraction osteogenesis(RED) in the case of cleft lip and palate with severe maxillary hypoplasia, 6 years 7 months old.