• Restorative Dentistry and Endodontics
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• v.17 no.1
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• pp.214-221
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• 1992

The five different types of bacteria, Bacteroides, Actinomyces, Capnocytophaga, Streptococcus, Fusobacterium which had frequently been recovered in infected canals, were investigated. The purpose of this study was to investigate the bacteriologic status in the traumatized nonvital teeth, and to investigate the effects of bacteria on the size of the le8ion and on the discoloration of teeth. The canal contents of sxiteen traumatized nonvital teeth were sampled and cultured aerobically and anaerobically for growth in five selective agar plates for five bacterial species. The sizes of the radiolucent areas in periapical films were measured and according to the sizes, the samples were divided into two groups. The discoloration of the teeth was checked and according to the existence of the discoloration, the samples were divided into two groups, also. The difference of bacterial colonial numbers in each group was investigated and the following results were obtained. 1. In traumatized nonvital teeth, all of the samples gave bacterial growth except one case. 2. Streptococcus was isolated in four cases but Bacteroides, Actinomyces, Fusobacterium and Capnocytophaga were not isolated. 3. The number of bacterial colonies was not found to be related the size of the lesion periapical films. 4. The number of bacterial colonies was not found to be related the discoloration of teeth.

• Imaging Science in Dentistry
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• v.53 no.2
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• pp.91-99
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• 2023

Purpose: This systematic review aimed to investigate the correlation between chronological age and dental pulp volume in cone-beam computed tomography (CBCT). Materials and Methods: The literature was searched in 4 databases(PubMed, Scopus, Web of Science, and Google Scholar). Within each study, the outcome of interest was the correlation (r) between chronological age and pulp volume. A random-effect meta-analysis was conducted. Subgroup analysis was carried out according to sex and tooth type. Results: Of 5,693 identified studies, 27 fulfilled the inclusion criteria and were selected for meta-analysis. These articles focused on single-rooted teeth (n=21), multi-rooted teeth (n=6), maxillary teeth (n=14), mandibular teeth (n=6), and maxillary and mandibular teeth (n=12). The relationship between chronological age and dental pulp volume was examined in the entire population (r= -0.67), men (r= -0.75), and women (r= -0.77) in single- and multi-rooted teeth. The results of the total population analysis showed a relatively strong negative relationship between age and pulp volume. Conclusion: This study suggested that CBCT is a reliable and repeatable tool for dental age estimation. A strong inverse relationship was observed between pulp chamber volume and age. Further studies on the correlation between chronological age and pulp volume of multi-rooted teeth may be beneficial.

• Journal of Dental Rehabilitation and Applied Science
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• v.19 no.3
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• pp.153-168
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• 2003

It is very important to arrange the artificial teeth correctly in bucco-lingual (labio- lingual) relation in reconstrcting dentition. Although many anatomic landmarks and techniques have been reported over the years, they are based on westerns. So this study was performd to examine the horizontal relations of mandibular teeth in Korean dentulous adults. 200 volunteers(mean age 22.9) who had natural dentition were selected. The impressions were taken with irreversible hydrocolloid impression material and mandibular study models were fabricated using class I dental stone. Then they were measured with 3-dimensional measuring device specially designed for this study. The results were as follows ; It is better to consider the lingual cusps of the lower posterior teeth as a guide than the linguoaxial surfaces of the lower posterior teeth, arranging the lower posterior teeth buccally to the line which starts from the mesial aspect of the lower canine and continue backward to the lingual aspect of the retromolar pad. It is better to arrange the fossae of the lower posterior teeth buccally to the line which starts from the cusp tip of the lower canine and continue backward to the top of the retromolar pad. The positions of the lower posterior teeth in the denture-bearing area ; considering the fossa as a guide, the 2nd premolar was positioned in center. considering the buccal cusp as a guide, the 1st molar and the 2nd molar were positioned in center. the distance ratio(d/a) was incresed constantly from the lower canine to the 2nd molar d ; the distance between the buccal vestibule(the lowest point) and the buccal cusp tips of the lower posterior teeth. a ; the distance between the buccal vestibule(the lowest point) and the lingual vestibule(the lowest point). The lower canine was positioned lingually($0.11{\pm}0.13$) than the labial vestibule, and the central incisor and the lateral incisor were positioned almost in the imaginary perpendicular plane of the labial vestibule(the lowest point).

• The Journal of the Korean dental association
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• v.19 no.1 s.140
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• pp.40-44
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• 1981

This study is proposed to analyze statistically the causes of extraction of permanent teeth among outpatients who visited our dental department of Sung-Sim Hospital, Chung-Ang University from Jan. 29th 1979 to Nov. 30th 1980. the results are as follows. 1. The group of patients aged 25-34 had more number of extracted teeth than any other age group. 2. It was found that woman's (0.13) was more than man's(0.9) in average number of extracted teeth per patient. 3. In analyzing the causes of extraction, it was identified as caries 37.5%, periodontal diseases 27.2%, wisdom teeth 17.6%, for orthodontic treatment and impacted supernumerary teeth and others 8.0% trauma and fracture 4.2%. 4. The primary cause of extraction was found to be changed from caries to periodontal diseases according to the increase of age. 5. The number of teeth that were extracted by trauma was found that man's (38) was more than twice as much as woman's (17) and the group of patients aged 35-44 had the most number of all age groups.

• The korean journal of orthodontics
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• v.47 no.5
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• pp.334-339
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• 2017

Objective: Teeth discoloration is a rare orthodontic complication. The aim of this study was to report the clinical progression of discoloration during orthodontic treatment. Methods: Discolored teeth, detected during orthodontic treatment between January 2003 and December 2012 by a single dentist using similar techniques and appliances, were analyzed. Results: The total number of teeth that showed discoloration was 28. Progression of discoloration was evaluated in only 24 teeth that were observed without any treatment. During the observation period, the discoloration "improved" in 8 of the 24 teeth (33.3%) and was "maintained" in 16 (66.6%). The electric pulp test performed at the time of initial detection of discoloration showed 14.3% positivity, which improved to 21.4% at the final follow-up. None of the initial and final follow-up radiographic findings showed any abnormalities. Conclusions: When teeth discoloration is detected during orthodontic treatment, observation as an initial management is recommended over immediate treatments.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.8 no.1
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• pp.5-9
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• 1978

The purpose of this study is to investigate the effect of dental restorations on the periodontal and periapical tissues. The author examined 620 cases of amalgam, 390 cases of gold inlay, 422 cases of crown and 644 cases of bridge through the standard intraoral films being appended in the charts that had been kept at the Dept. of Oral Diagnosis in Seoul National University Hospital. This study obtained the following results; 1. The restorations of amalgam, gold inlay crown and bridge were found more frequently in female than in male. 2. The restorations of amalgam, gold inlay and crown were found more numerously in mandibular teeth than in maxillary teeth in both sexes. But in the case of crown, the fact is quite the reverse especially in anterior teeth. 3. On the contrary, in the case of bridge, the restorations of bridge were much more distributed in the maxillary teeth than in the mandibular teeth. 4. Roentgenographic changes of periodontal tissues whose teeth were treated with any type of four restorations were periodontal space widening, lamina dura discontinuity and periapical lesion in the order described in both sexes. 5. On the occasion of between amalgam and gold inlay or between crown and bridge, the differences of periodontal changes were of no consequence. On the other hand, the differences of periodontal changes were apparant between the group of amalgam & gold inlay and the group of crown & bridge.

• Journal of the korean academy of Pediatric Dentistry
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• v.7 no.1
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• pp.41-45
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• 1980

The term "Oligodontia" or "Hypodontia" have been used to describe variable degrees of reduction in number of teeth. Oligodontia may occur alone or as a result of some syndrome. Although the teeth are derived in part from ectoderm, the current opinion of reason of oligodontia should be reserved for those disorders in which there is abnormal development of one or more ectodermal tissues. 7 year 5 months old female was refered to the department of pedodontics, college of dentistry Yonsei university for evaluation and replacement of absent teeth. She had no special inf.ectious disease in her childhood, and her parents were healthy. She had no special syndrome of ectodermal disorders except the saddle nose, yellow and fine hair, and notched upper anterior central incisor. Panex radiogram was showing 6 anterior primary teeth, 2 permanent first molars and 2 unerupted first bicuspid in mandible. Another permanent teeth were absent. and normal number of primary and permanent teeth in maxilla. Lateral cephalogram showed no special abnormality in growth pattern. We had evaluated lower anterior decayed teeth with jacket resin and chrome steel crown and removable partial denture at missing area. We had got good results for rehabilitation of function and aesthetic.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.24 no.1
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• pp.129-135
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• 1994

This study was performed to evaluate the accuracy of orthopantomogram by measuring the actual and radiographic tooth length and by analyzing the vertical magnification rate. For this study, total 90 teeth of the maxilla and mandible teeth and a dry skull were used. This experiment was attached with metal balls of 1±0.02㎜ at the root and the crown cusp tips of central, 2nd premolar, 1st molar of the maxilla and mandible and the teeth were embedded in dry skull, and then orthopantomogram was taken. The obtained results were as follows: 1. The average of tooth length in orthopantomogram was longer than that of actual tooth length. 2. The average of vertical magnification rate in the orthopantomogram to actual tooth length was 17-26%. 3. Vertical magnification rate of the maxilla teeth was 18-26% and that of mandibular teeth was 17-23%, and the magnification of maxillary teeth was larger than that of mandible teeth(P<0.0l). 4. Vertical magnification rate of posterior area was 22-26% and that of anterior area was 17-18%, and the magnification of anterior area was less than that of posterior area(P<0.01).

• The Journal of the Korean dental association
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• v.58 no.3
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• pp.169-179
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• 2020

The purpose of this study was to investigate the principal reasons for primary teeth extractions and the tooth type extracted in children. 1159 patients were selected in this study. Dental records and radiographs were reviewed and age, gender, medical history, type of tooth extracted and the reasons for extraction were collected. The data were statistically analyzed using Chi-square test. Total 2078 primary teeth were extracted. Central incisors(34.1%) were most frequently extracted. Extractions due to physiological mobility(77.5%) were the most frequent followed by caries(13.8%), orthodontic(3.9%), trauma(1.7%). Reason for the extraction was different according to age (p = 0.000), but there was no difference according to gender (p = 0.109). While extractions due to physiological mobility predominated overall, reason for extraction was different according to the tooth type. There was no previous treatment in 54.6% of primary teeth extracted due to caries. Excluded physiological mobility, caries are the most common reason for extraction of primary teeth. The importance of preventive care should be emphasized in order to preserve primary teeth and improve children's oral health.

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.2
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• pp.235-241
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• 1999

The bond failure of resin teeth In denture base resin is one of the failure in prosthodontic treatment. The purpose of this study was to evaluate the bond strength of artificial resin teeth to the denture base resins. Specimens were made with heat curing acrylic resins (Vertex Rs, Lucitone 199) and artificial resin teeth (Tiger, Trubyte biotone, Endura, Orthosit, Tubyte bioform IPN) and the bond strength were measured with testing machine(Zwick. Germany) and the mode of bond failure were observed. The results were as follows; 1. The bond strength of Vertex Rs to artificial resin teeth was the highest in Tubyte biotone, and It was the lowest in Tiger and Trubyte bioform IPN. 2. The bond strength of Lucitone 199 to artificial resin teeth were higher in Orthosit and Trubyte bioform IPN than in Tiger and Trubyte biotone. 3. The bond strength of Trubyte biotone to Vertex Rs was higher than to Lucitone 199 and that of the Trubyte bioform IPN to Lucitone 199 was higher than to Vertex Rs. 4. Nearly all bond failures of specimens occured cohesively within the resin teeth.