• 대한치과보철학회지
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• 제34권1호
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• pp.85-99
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• 1996

Finite element models were constructed to analyze the mechanical behavior of a three unit fixed partial denture (FPD) with a 2nd premolar and 2nd molar abutment either employing a rigid and nonrigid connector. Gap elements were used to model the clearance space of the nonrigid connector. 1. High stress was generated in the FPD and supporting abutment around the rigid connector. 2. The pattern of stress and deflection is very similar between vertically and 20 degree mesially tilted nonrigid connector at the distal aspect of premolar abutment. 3. FPD with an inverted nonrigid connectors exhibited the worst undesirable mechanical stress states and deformations. 4. Nonrigid connector of normal orientation transmit the load to the abutment tooth, but inverted connector doesn't transmit the force.

• 대한치과교정학회지
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• 제10권1호
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• pp.55-64
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• 1980

The purpose of this study was to investigate the interrelationship of the experimental group and control group by analyzing case histories, intraoral radiographs, orthopantomographs, intraoral slide films and dental casts. The data for this study were complied from 654 outpatients of the Department of Orthodontics, Seoul National University Hospital. The following conclusions were obtained. 1. When one or more thins molar teeth were congenitally missing, the incidence of the other congenitally missing teeth was high. 2. The frequency of congenitally missing teeth was comparatively higher in male, maxilla, class II and class III. 3. The congenitally missing srea of the third molar by Angle's classification was not significant. 4. The order of frequency of congenitally missing teeth was the third molar, the second premolar, the lateral incisor, the first premolar, the central incisor, the canine, the first molar, the second molar.

• 대한치과의사협회지
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• 제12권9호
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• pp.707-712
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• 1974

The 800 extracted permanent teeth of first and second premolar were observed and obtained the following results: Those teeth were extracted from the population of dentistless rural area. The cause of extraction of those teeth was only the dental caries. It was performed by the free dental service team from 1966 to 1973. The findings were as follows: 1. The most incidence of caries occurrence was on the distal surface and the least was mesial side occlusal surface. 2. The average rate of decayed surface was higher in the second premolar group than the first permolar. 3. The average rate of decayed surface was higher in the teeth of mandible than maxilla. 4. The average rate of decayed surface was higher in female than male. 5. The average rate of decayed surface per tooth was 3.05±1.83.

• 대한소아치과학회지
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• 제24권3호
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• pp.487-494
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• 1997

It is rare to find multiple supernumerary teeth in individuals with no other associated diseases or syndromes. 'Non-Syndrome multiple supernumerary teeth' reviewed by Yusof(1990) have more frequency of occurrence in the mandibular region. Especially, mandibular premolar region appears to be the site of predilection for no n-syndrome multiple supernumerary teeth. Also, these may develop after most permanent teeth have erupted, thus their effect upon the occlusion is limited. In this case, the patient had 20 supernumerary teeth without other associated diseases or syndromes. All of the supernumerary teeth were impacted, and thirteen of them were found in the premolar region. In the radiographic and clinical finding, other specific complication resulted from the supernumerary teeth weren't observed.

• 대한소아치과학회지
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• 제5권1호
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• pp.7-11
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• 1978

Of 633 children, 334 in male and 299 in female, whose ages ranged from 3 to 13 years old, the amounts of development of teeth germ were observed according to ages with oblique lateral cephalogram to study the developing state of teeth germ of mandibular premolars. The results were as followings; 1. The time of actively develop:ng tooth germ was observed about 10 years old both in male and in female. 2. The increasing rate of development of tooth germ a year was higher in female than in male at mandibular 1st premolar and in male than in female at mandibular 2nd premolar. 3. Age of complete tooth germ development was earlier in female than in male at mandibular 1st and 2nd premolars.

• 치과방사선
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• 제6권1호
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• pp.7-14
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• 1976

This study was done using the 45° oblique lateral old, 18 males and 27 females, with normal occlusion, premolars and molars on upper and lower jaws. Axial inclination to nasal floor, occlusal plane and inter-axial inclination were examined. In addition the position of each tooth was examined in height and depth in upper and lower jaws. The results were obtained as follows; 1. The inclination of long axis of upper 1st premolar was most nearly perpendicular, upper canine was tilted mesially, and 2nd premolar and molars were tilted distally. 2. The inclination of long axis of lowers molar were tilted mesially. 3. There were no severe variation on the inter-axial inclination of canine to mandibular plane, and 2nd molar.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.171-172
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• 2006

Most existing studies for stress analysis of teeth have employed small number of teeth, and used big element size using F-E models. Therefore, the results are not accuracy enough for showing the internal stress variation. 15 males' and 13 females' mandibular first premolar are employed for internal structure's study of teeth and small element size for a FE model are used. According to these processes, stress distribution of internal parts of teeth are well shown, and the stresses are varied a lot between enamel layer and dentine layer, but there is little variation on pulp chamber.

• 치과방사선
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• 제2권1호
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• pp.47-51
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• 1972

The author measured the distance from mental foramen to the occusal plane and classified the positional frequency of mental foramen to the tooth site using topography. The results were obtained as follow; 1. Of 964 mental foramen taken, the common site was in 2nd premolar region showing 64.08 per cent in right and 57.17 per cent in left site. 2. The average distance from occlusal plane to the upper border of premolar region was 23.20㎜. and lower border was 25.07㎜. 3. The positional variation of mental foramen was 4.77 per cent were located above the apex of the nearest tooth, and 50.42 per cent were located at the apex of the nearest tooth and 44.81 per cent were located below the apex of the nearest tooth.

• 대한치과의사협회지
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• 제41권9호통권412호
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• pp.631-636
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• 2003

Bacteria play a major role in the etiology of apical periodontitis. Traditionally it has been held the microorganisms are present in necrotic tissue in the root canal system and in tubules of the root dentin whereas the periapical tissues are free of bacteria. However, it is reported the presence of bacterial in the periapical lesions. They may form the biofilm and survive in the periapical tissues. Especially high incidence of biofilm is reported in the refractory periapical lesions. treatment was presented in the left maxillary first premolar with a long-standing fistula and apical calculus. Also. the role of biofilm and its treatment were discussed.

• 한국임상수의학회지
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• 제20권1호
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• pp.138-141
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• 2003

First case, a one-year-old female Shih Tzu weighing 3 kg with closed transverse fractures of bilateral mandibular body between 2nd and 3rd premolar teeth were treated surgically with bone plates and screws, and cranial luxation of temporomandibular joints were reduced to closed method. Second case, a 8.4 years old male Yorkshire terrier weighing 2.6 kg with closed transverse/oblique fractures of bilateral mandibular body between premolar and molar teeth were treated surgically with bone plates and screws. Radiographic examination revealed that the fractures in two cases fixed well and temporomandibular joint was stabilized. One month after operation, jaw activity was excellent and malocclusion wasn't observed.