• The Journal of Korean Academy of Prosthodontics
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• v.43 no.2
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• pp.158-175
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• 2005

Statement of problem. Every effort has been continually made to obtain objectivity in measuring the longevity of fixed restorations, such as by establishing unified judgement standard for deciding success and adopting statistical method that analyzes the data of successful and failed cases at the same time. In Korea, however desired level of development has not to be made in this field yet. Purpose. This study, adopting California Dental Association (CDA) quality evaluation system, established objective standard for deciding success, and inferred the longevity of fixed restorations and their failure analysis through adopting Kaplan-Meier survival analysis. Material and method. In order to assess the longevity of flxed restorations serviced in Korea and causes of failure, a total of 1109 individuals (aged 15-74, 716 women and 393 men loaded with 2551 unit fixed restorations, and 1934 abutments) who lived in Kyung-In Province were examined and the findings were as follows : Results. 1. Length of service of fixed restorations serviced in Korea was 6.86$\pm$0.15 yr (mean), 5.5 yr (median), and the rate of success was 65.82% in 5 year survival, and 21.15% in 10 year survival. 2. When there was patient's need for replacing old prosthetics, longevity of fixed restorations was 7.51$\pm$0.27 yr (mean), 7 yr (median), and the rate of success was 61.08% in 5 year survival, and 17.57% in 10 year survival. 3. Longevity of fixed restorations was longest in the over-sixty age group(9.21$\pm$0.66) and that of the teen age group(3.39$\pm$0.28) was shortest (p<0.05). 4. Longevity of fixed restorations of women (7.38$\pm$0.18 years) was longer than that of men (6.00$\pm$0.26) (p<0.05). 5. As for the provider factor (such as unlicensed performers, university hospitals, and private clinic), there was no statistically significant difference in longevity of fixed restorations. 6. Defective margin (34.78%). periodontal disease (12.15%), periapical involvement (11.73%), was the most frequent causes of failure and poor esthetics group showed the longest life above all (p<0.05). Actual frequent causes of failure after removing old prosthetics were defective margin, periapical involvement, periodontal disease and uncemented restoration. In 75.67% of the cases, abutment state after removing old prosthetics was good enough for loading another prosthetics. 7. There was found to have statistically significant influence between longevity of single crown (6.35$\pm$0.20 yr) and that of 3 unit fixed restorations (7.60$\pm$0.30 y) (p<0.05). In each case the most frequent cause of failure was defective margin. 8. The number of cantilever pontic, pontic/abutment ratio, oral hygiene status were found to have no statistically significant influence on longevity of fixed restorations in all groups (p>0.05). 9. Longevity of fixed restorations made of non precious metal was longest (9.60$\pm$0.40 yr) semi precious and precious trailing behind(p<0.05). 10. Group function group (37.04%) and partial group function group (44.62%) were predominant in frequency but showed no correlation between them and among different types of occlusal plane and different types of occlusal surface (p>0.05). 11. Longevity of fixed restorations was longest in the centric interference group(9.35$\pm$0.62) (p<0.05) among different types of occlusal interference. Conclusion. We found that longevity of fixed restorations serviced in Korea is affected by age, gender and type of material, and that most frequent cause of failure is defective margin. In order to assess the accurate longevity of axed restorations, unified research design. overcoming inter-observer difference and establishing the objective research items are needed. Furthermore, it is thought that prospective approach through thorough study and regular follow-ups is needed just from the start of research. Nationwide detailed studies on length of service of fixed restorations manufactured in Korea are hoped to be conducted hereafter.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.15 no.2
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• pp.81-91
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• 1993

Arthrosis of the temporomandibular joint is defined as a disease of a joint with chief complaint of pain, clicking, limited jaw movements. Generally, most patients with the temporomandibular arthrosis can be treated conservatively with muscle relaxation therapy combined with mandibular repositioning prostheses, followed by occlusal equilibration, restorative dentistry and/or orthodontics, and many other forms of treatment. In case prior nonsurgical treatment proved to be ineffective or the disease is chronic and severe, surgical operation is recommended. For patients with arthrosis of the temporomandibular joint, only discectomy as therapeutic method of the surgical treatment should not be applied and the removed articular disc of the temporomandibular joint should be replaced. Allograft such as Proplast-Teflon, Silastic, etc have been used as replacements of removed articular disc. However, these allograft materials have caused complications such as inflammatory changes, foreign body reactions. As a result, a replacement material which is autogenous, space occupying, easy to harvest and less inflammatory change has been developed. Auricular cartilage with perichondrium satisfies many of these requirements. The apparent advantages of autogenous auricular cartilage as an interpositional graft after a discectomy are as follows, (1) the form of the external ear corresponds to joint morphology, (2) a graft of adequate size can be harvested, (3) the form of the external ear remains unchanged after surgery, (4) the graft can be obtained adjacent to the surgical site, (5) biologically acceptable material is used, (6) the additional expense of allogenic graft is avoided. Because we considered autogenous auricular cartilage as a good replacement material, removed articular disc has been replaced with fresh autogenous auricular cartilage in the case of three patients. The result of the treatment is favorable, and the cases being presented here.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.3
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• pp.492-498
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• 1999

Oculodentodigital syndrome(ODD) was first reported by Lohmann in 1920 and termed by Meyer Schwicketath, which they called "dysplasia oculo-dento-digitalis" in 1957. It is somewhat rare heritable disease. ODD is generally inherited in an autosomal dominant pattern with a complex phenotype. The characteristic features are : (1) unique facial features, (2) microphthalmos, (3) syndactyly and camptodactyly of 4th and 5th fingers, (4) osseous anomalies of the middle phalanges of 5th fingers and toes, (5) enamel hypoplasia, (6) dry lusterless hair. We found several occlusal wearing and yellow discoloration of succedaneous teeth, multiple caries lesions, premature loss and pulpal involvement of primary teeth with associated enamel abnormalities caused by generalized enamel hypoplasia in a fairly constant oral finding. Occasionally partial anodontia, microdontia and cleft lip and palate can be manifested. This case, a 9-year-old female with repaired bilateral syndactyly was referred to pediatric dental clinic, Pusan National University Hospital for evaluation of severe attrition of teeth and caries lesions. She had most of the above mentioned typical manifestations of the syndrome. Dental treatment including caries control, stainless steel crown were performed.

• Journal of Oral Medicine and Pain
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• v.20 no.2
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• pp.407-420
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• 1995

This study was performed to evaluate and compare conservative treatment results by several parameters such as age, sex, symptom duration, type and timing of joint sound, parafunctional habits, splint type, and diagnostic classification. There have been too many articles reporting long term results of conservative treatment but articles related to comparison of treatment results by patients' self-evaluation have been rarely reported. For this study 258 patients with temporomandibular disorders(TMDs) were selected and examined by routine diagnostic procedure for TMDs. The subjects were classified into 5 TMDs subgroups ad treated with conservative treatments involving splints, physical modalities, jaw exercises, and counseling. Visual analogue scale(VAS) about pain, joint sound, and mouth opening limitation was recorded respectively during treatment period. From the VAS data and treatment duration, VAS treatment index(VAS Ti) was calculated. The obtained results were as follows : 1. Pain was the most frequent main symptom in subjects with temporomandibular disorders, and main symptom for mouth opening limitation was comparatively less than for pain or sound in disk displacement with reduction group or in degenerative joint disease group. 2. Degenerative joint disease group had the most poor treatment results and highest occlusal index of Helkim's index. 3. Good prognosis for conservative treatment was observed in acute group, under 6 months than chronic group, 6months over in symptom duration, and subjects with 40 years over in age showed the most poor prognosis. 4. Subjects treated with anterior repositioning splint had better treatment results than subjects treated with centric relation splint, but statistical significance in VAS Ti and treatment duration was not observed. 5. Treatment results according to affected side, types and point of joint sound did not show consistent statistical results. 6. The result for conservative treatment was observed poor in subjects with bruxism and clenching. 7. In studying coincidence between preferred chewing and affected side, frequency of preferred chewing side, in unilateral affection, was higher in ipsilateral than in contralateral side.

• Journal of Periodontal and Implant Science
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• v.35 no.1
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• pp.53-63
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• 2005

Number of fixtures supporting prosthesis for rehabilitation of partial edentulism in distal area is an important factor in distal area to the bone tissue response around dental implant. Optimal number and optimal positioning of dental implant has leaded to the stable condition of bone tissue and successful long-term treatment outcome. This clinical and radiographic study was performed to document and evaluate the short-term result of occlusal rehabilitation by means of implant-supported fixed prostheses (ISPs) especially for partial edentulism in distal area in patients treated for advanced periodontal disease and to verify the number of fixture affecting the bone tissue response. A total of 30 consecutive patients referred because of advanced periodontal disease were included. Before the implant therapy was initiated, periodontal treatment was performed and the outcome evaluated during at least a 6-month period. An individual maintenance care program was designed for each patient. All 75 implants were placed using a 2-stage surgical approach. The patients were divided into 2 groups, in one of which two fixtures were placed and in the other of which three fixtures were placed with tripodal geometry. Following installation of the ISPs, all patients underwent a baseline examination including evaluation of i) oral hygiene, and ii) periodontal/ peri-implant conditions, and iii) radiographs. These examinations were repeated annually during the 1 or 2-year observation period. The results were as follows: 1.No single implant was lost during the observation follow-up period. 1.The percentage of plaque harboring surfaces and bleeding units upon probing were found to be low (<10%), and no soft tissue complications were recorded. 1.Two-fixture group showed bone destruction ranged from 0.0mm to 1.5mm and the mean was 0.31mm. Three-fixture group showed more bone destruction of 0.51mm. There was no statistically difference between two groups. These results suggested that the factor for success is not the number of fixture but the strict maintenance of peri-implant tissue health and initial stability of fixture.

• Restorative Dentistry and Endodontics
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• v.25 no.3
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• pp.321-337
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• 2000

Dental caries, one of the most frequent dental disease, become larger because it can be thought as a simple disease. Further more, it can progress to unexpected root canal therapy with fabrication of crown that needs reduction of tooth structure. Base is required in a large caries and ZOE, ZPC, glass ionomer are used frequently as base material. They, with restorative material, can affect the longevity of the restoration. In this study, we assume that the mandibular 1st molar has deep class I cavity. So, installing the 3 base material, 3 kinds of fillings were restored over the base as follows; 1) amalgam only, 2) amalgam with ZPC, 3) amalgam with ZOE, 4) amalgam with GI cement, 5) gold inlay with ZPC, 6) gold inlay with GI cement, 7) composite resin only, 8) composite resin with GI cement. After develop the 3-dimensional model for finite element analysis, we observe the distribution of stress and temperature with force of 500N to apical direction at 3 point on occlusal surface and temperature of 55 degree, 15 degree on entire surface. The analyzed results were as follow : 1. Principal stress produced at the interface of base, dentin, cavity wall was smallest in case of using GI cement as base material under the amalgam. 2. Principal stress produced at the interface of base, dentin, cavity wall was smaller in case of using GI cement as a base material than ZPC under gold inlay. 3. Composite resin-filled tooth showed stress distributed over entire tooth structure. In other words, there was little concentration of stress. 4. ZOE was the most effective base material against hot stimuli under the amalgam and GI cement was the next. In case of gold inlay, GI cement was more effective than ZPC. 5. Composite resin has the small coefficient of thermal conductivity. So, composite resin filling is the most effective insulating material.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.37
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• pp.39.1-39.6
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• 2015

Skull-base osteomyelitis is a rare disease affecting the medulla of the temporal, sphenoid, and occipital bones. In general, it occurs due to external ear canal infections caused by malignant external otitis. Skull-base osteomyelitis usually affects elderly diabetic patients. The patient, a 58-year-old man, was referred for evaluation and management of the left jaw. Clinical examination of the patient revealed pain in the left jaw and mouth-opening deflection to the left. The maximum active mouth opening was measured to about 27 mm. Panoramic, CT, and CBCT revealed bone resorption patterns in the left condyle. Through control of diabetes, continued pharmacological treatment, arthrocentesis, and occlusal stabilization appliance therapy were carried out. The extent of active mouth opening was increased to 45 mm, and pain in the left jaw joint was alleviated. This was a case wherein complications caused by failure to control diabetes induced skull-base osteomyelitis. There is a need for continued discussion about the advantages and disadvantages of arthrocentesis with lavage for patients with skull-base osteomyelitis and other treatment options.

• Journal of Oral Medicine and Pain
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• v.30 no.1
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• pp.45-55
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• 2005

As people prefer to use right or left hand, some have preferred chewing side while others do not. Totally, 82 volunteers composed of students and staffs from Dental Hospital College of Dentistry Yonsei University participated in this study for the investigation of influence of preferred chewing habit, that has lasted for more than a year, on electromyographic(EMG) activity of masticatory muscles and bite force. Among the 82 volunteers, 46 had preferred chewing habit while the other 36 did not. Prior to the investigation, those with factors that could affect the study, such as, general disease, irregular dentition and malocclusion, were screened and excluded by questionnaire and clinical examination. The results were as follows: 1. There was no significant difference in EMG activities between chewing side and non-chewing side of preferred chewing subjects at rest as well as maximal voluntary contraction(MCV)(p>0.05). 2. Asymmetrical coefficient of temporal and masseter muscle EMG activities between preferred chewing subjects and non-preferred chewing subjects at rest was not significantly different(p>0.05). 3. Asymmetrical coefficient of masseter EMG activity was significantly higher(p<0.05) than that of non-preferred chewing subjects at MCV, whereas that of anterior temporal muscle showed no difference(p<0.05). 4. In preferred chewing subjects, there was no significant difference in average bite force and occlusal contact area between chewing side and non-chewing side(p>0.05). 5. There was no significant difference in Asymmetrical coefficients of average bite force and occlusal contact area between preferred chewing subjects and non-preferred chewing subjects (p>0.05). Consequently, preferred chewing habit can be considered as physiological asymmetry with normal function rather than to have influence on EMG muscle activity of masticatory muscles, average bite force and occlusal contact area. Objective standardization to differentiate preferred chewing subjects and non-preferred chewing subjects should be established in the further study.

• Journal of Oral Medicine and Pain
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• v.20 no.2
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• pp.291-306
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• 1995

Mandibular movement is composed of border movement and functional movement. Border movement such as maximal mouth opening, hinge opening ad lateral eccentric movement has good reproducibility, but functional movement such as chewing, swallowing and speech has also reproducibility. Especially for chewing movement, individual reproducibility has been confirmed by many studies. Study of chewing pattern is still in controversy. In new approach for raising the diagnostic value, numeric parameters and morphologic characteristics could be used for evaluation of chewing pattern. This study was performed to investigate the differences between chewing pattern in controls and in patients with temporomandibular disorders. Sixty-three patients with temporomandibular disorders participated in this study, and they were divided into unilaterally affected subjects or bilaterally affected subjects. Then unilaterally affected subjects were classified into closed lock group, disk displacement with reduction group, and degenerative joint disease group. For recording of chewing pattern, subjects were asked to chew one piece of presoftened chewing gum on both sides, and the chewing movement was recorded with the Electrognatho- Graphy(Bio-Research Associates Inc., U.S.A.). Tooth contact pattern for occlusal stability (Total left-right statistics )was also recorded with T-Scan(Tekscan Co., U.S.A.). The dta related to chewing pattern and total left-right statistics were statistically analyzed by SAS/stat program. The obtained results were as follows : 1. In patient group, mean value of A-P distance and the ratio of A-P distance to vertical distance were larger than control group, but the value of lateral distance in affected side and the closing velocity in unaffected side were smaller than that of control group, respectively. 2. In case of unilateral affected patients, chewing pattern of other side had tendency to restricted movement and slow velocity in closed lock group or degenerative joint disease group than control group or disk displacement with reduction group. 3. In bilateral degenerative joint disease patients, contralateral side had tendency to large range of motion and slow chewing velocity than preferred chewing side. 4. The patients with restricted mouth opening below than 35mm had higher value of total left-right statistics than patient group mouth opening above 35mm. Also closed lock group had higher total left-right statistics than disk displacement with reduction group, degenerative joint disease group and control group. 5. There was some difference in morphologic characteristics of chewing pattern between in control group and in affected side of unilateral patient group, but no difference between control group and unaffected side of unilateral patient group. 6. There were positive correlations between vertical distance and A-P distance, between vertical distance and chewing velocity, between A-P distance and chewing velocity, and between opening velocity and closing velocity in unilateral affected patients.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.2
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• pp.137-145
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• 2011

The purpose of this study was to obtain the data for dental caries experience and occlusal pattern to utilize these data for motivating oral health promotion and activating oral health care programme in preschool children of multicultural family. Caries prevalence on primary teeth was surveyed for 3-5 years old 190 children of multicultural families in Chonbuk province. The results were as follows : 1. Dental caries prevalence rate of primary teeth (dmf rate) was 61.7% at 3 years of age, 88.7% at 4 years of age, and 92.6% at 5 years of age (p>0.05). 2. Average score of dmft index was 2.22 at 3 years of age, 4.97 at 4 years of age, and 6.62 at 5 years of age (p>0.05). 3. Most of the caries-prevailed tooth was maxillary primary central incisor and showed 28.8% at 3 years of age, 56.7% at 5 years of age. 4. dmft index and dmfs index of children of Vietnamese, Cambodian, and Filipinos women were higher than those of Chinese and Japanese. 5. In sagittal primary molar relationship, flush terminal plane type was 82.6%, distal step type was 5.2% and mesial step type was 8.4%. This study is the first report for children of multicultural families in Korea. More attention for children of multicultural families will be needed in aspect of oral disease prevention and treatment.