• Restorative Dentistry and Endodontics
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• v.7 no.1
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• pp.117-124
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• 1981

In order to observe the frequency of visits and the distribution of endodontically treated patients according to age, sex, diagnosis, type of teeth, the author had surveyed the 17,250 outpatients of the Infirmary of the College Dentistry, Yonsei University from January 1976 to December 1978. 773 cases, 660 patients among 728 endodontically treated patients were studied. The obtained results were as follow; 1. The average frequency of visits were 5.95 in uppers and 5.88 in lowers. 2. The average frequency of visits were 5.79 in males and 6.02 in females. 3. At the age of under 14, the average frequency of visits were 7.42 in uppers and 6.76 in lowers. 4. According to diagnoses, the average frequency of visits in periapical granuloma or cyst were 2.80 in uppers and 3.16 in lowers. 5. The number of endodontically treated teeth had revealed as follow; upper incisors 27.94%, lower molars 25.87%, and upper molars 15.13% 6. The number of endodontically treated teeth by diagnoses were as follow; periapical abscess 45.27%, pulpit is 37.51%, tooth fracture 8.40%. 7. The number of endodontically treated teeth were 51.99% in the age of from 20 to 34.

• Journal of Korean society of Dental Hygiene
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• v.20 no.3
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• pp.303-312
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• 2020

Objectives: The purpose of this study was to investigate the relationship between periodontal disease, number of remaining teeth with high-sensitivity C-Reactive protein in Korean adults aged 40 and older. Methods: The study used the Sixth Korea National Health and Nutrition Examination Survey (KNHANES VI-3), 2015. The study sample consisted of 3,883 aged 40 years or older who had completed the health survey and the health examination. Logistic regression analyses were performed to examine the odds ratios of high-sensitivity C-Reactive protein by periodontal disease and number of remaining teeth, adjusting for demographic characteristics, chronic diseases and oral health behavior-related variables. Results: When the demographic and chronic diseases were adjusted, the risk of high-sensitivity C-Reactive protein (hs-CRP) average 1.23 mg/L or higher was 1.36 times higher in patients with periodontal disease between the ages of 40 and 49, but it was not significant (OR=1.36; 95% CI=0.82-2.23). In addition, in the group of 0~23 remaining teeth aged 40~49 years, the risk of higher than the average 1.23 mg/L of high-sensitivity C-Reactive protein was 2.03 times higher (OR=2.03; 95% CI=1.10-3.74), and 1.49 times higher in 60~69 years (OR=1.07; 95% CI=1.04-2.76). Conclusions: This study found that periodontal disease and tooth loss in Korean adults aged 40 and older was significantly associated with high-sensitivity C-reactive protein.

• The Journal of Korean Academy of Prosthodontics
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• v.53 no.1
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• pp.46-50
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• 2015

Restoration of a patient with thin and low residual ridges using a removable partial denture cannot provide proper anterioposterior stability and support, so it results in patient discomfort and severe occlusal force. Also, when a small number of residual teeth are far apart from one another, it is difficult to splint. When these teeth are not splinted, they become solitary abutments, which is not a wise treatment decision. In this case, telescopic system reduces severe lateral load on abutments resulting from a clasp denture and it provides stable and definite retention and solidity. In this case report, a patient exhibited full edentulism in maxilla, and a small number of residual teeth in mandible, which were restored with a complete denture and a telescopic denture respectively. In treatment planning, it was concluded that a patient was restored with a telescopic denture since it was highly probable that a clasp denture would create discomfort and difficulty due to a small number of residual teeth located far apart and residual ridges without proper support.

• Journal of the korean academy of Pediatric Dentistry
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• v.6 no.1
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• pp.27-33
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• 1979

The author studied the response to the stimulation of an electric pulp stimulator of healthy 854 permanent anterior teeth in 122 children aged from six to eleven years old, during different stages of tooth development. The results were as followings: 1) In completely open apices, 13.1% (18 teeth) showed positive responses, and 86.9% (120 teeth) showed negative responses. In two-thirds open apices 33.1% (75 teeth) showed positive responses, and 66.9% (152 teeth) showed negative responses. In one-third open apices 57.8% (118 teeth) showed positive responses, and 42.2% (86 teeth) showed negative responses. In closed apices 80.0% (228 teeth) showed positive responses, and 20.0% (57 teeth) showed negative responses. 2) The number of positive responses increased in each upper and lower central incisors during the stages of root development, but not in upper lateral incisors. 3) There were no significant differences statistically in responses between the teeth of the right and left sides and the upper and the lower jaw, in the same stages of root development.

• Imaging Science in Dentistry
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• v.51 no.3
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• pp.271-278
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• 2021

Purpose: This study aimed to investigate the panoramic imaging features of cleidocranial dysplasia (CCD) with a relatively large sample. Materials and Methods: The panoramic radiographs of 40 CCD patients who visited Seoul National University Dental Hospital between 2004 and 2018 were analyzed. Imaging features were recorded based on the consensus of 2 radiologists according to the following criteria: the number of supernumerary teeth and impacted teeth; the shape of the ascending ramus, condyle, coronoid process, sigmoid notch, antegonial notch, and hard palate; the mandibular midline suture; and the gonial angle. Results: The mean number of supernumerary teeth and impacted teeth were 6.1 and 8.3, respectively, and the supernumerary teeth and impacted teeth were concentrated in the anterior and premolar regions. Ramus parallelism was dominant (32 patients, 80.0%) and 5 patients (12.5%) showed a mandibular midline suture. The majority of mandibular condyles showed a rounded shape (61.2%), and most coronoid processes were triangular (43.8%) or round (37.5%). The mean gonial angle measured on panoramic radiographs was 122.6°. Conclusion: Panoramic radiographs were valuable for identifying the features of CCD and confirming the diagnosis. The presence of numerous supernumerary teeth and impacted teeth, especially in the anterior and premolar regions, and the characteristic shapes of the ramus, condyle, and coronoid process on panoramic radiographs may help to diagnose CCD.

• The korean journal of orthodontics
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• v.27 no.2
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• pp.259-272
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• 1997

This study was performed to locate the anteroposterior position of the center of resistance of upper anterior teeth when intrusive forces are acted on them by applying segmented arch mechanics. Three-dimensional finite element model of upper six anterior teeth, periodontal ligament and alveolar bone was constructed The locations of the center of resistance were compared according to the three variables, which are number of teeth contained in anterior segment, axial inclination of anterior teeth, and degree of alveolar bone loss. The following conclusions were drawn from this study; 1. When the axial inclination and alveolar bone height were normal, the locations of center of resistance of anterior segment according to the number of teeth contained were as follows; 1). In 2 teeth segment, the center of resistance was located in the distal area of lateral incisor bracket 2) In 4 teeth segment, the center of resistance was located in the distal 2/3 of the distance between the brackets of lateral incisor and canine. 3) In 6 teeth segment, the center of resistance was located in 3mm distal of canine bracket, which is interproxirnal area. between canine and 1st premolar. 4) As the number of teeth contained in anterior segment increased, the center of resistance shifted to the distal side. 2. As the labial inclination of incisors increased, the center of resistance shifted to the distal side. 3. As the alveolar bone loss increased, the center of resistance shifted to the distal side.

• Journal of dental hygiene science
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• v.19 no.2
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• pp.96-106
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• 2019

Background: Factors affecting oral function include tooth number, oral muscle strength, and oral diseases. This study aimed to investigate the relationship among oral environment, muscle, and microbiology. Methods: Fifty-six elderly individuals in a day care center were included in the study. The survey regarding tongue and lip muscle strength and oral microorganisms was conducted from November to December 2018. Results: Tongue and lip muscle strength were greater in men than women (p>0.05). Tongue muscle strength was greater in the ${\leq}80-year-old$ group ($34.94{\pm}9.85$) than the ${\geq}90-year-old$ group ($25.57{\pm}7.54$) (p<0.05). Tongue muscle strength and lip muscle strength were greater in the ${\geq}15$ functional teeth group ($34.08{\pm}9.31$ and $9.25{\pm}1.63$, respectively) than in the <15 functional teeth group ($28.08{\pm}7.53$ and $7.76{\pm}1.51$, respectively) (p<0.05). Age was significantly correlated with functional tooth number, denture use, and tongue muscle strength. The number of functional teeth was positively correlated with tongue muscle strength, lip muscle strength, and oral microorganisms. Denture use was negatively correlated with tongue and lip muscle strength. Tongue muscle strength was significantly correlated with lip muscle strength. The number of Eubacterium nodatum was higher in men than women. The number of Parvimonas micra and Enterococcus faecalis was higher in the groups with ${\geq}15$ functional teeth, denture use, and greater tongue and lip muscle strength. The number of Lactobacillus casei was higher in the group that uses dentures and with greater tongue strength. Conclusion: Oral microbiology is more important in oral environment and management than oral muscle function. The correlation between oral muscle and oral microorganism requires further study. Therefore, oral care training should be conducted to improve the oral care practice of elderly individuals, maintain oral health through oral care, and prevent the decrease in saliva secretion by aging.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.22 no.2
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• pp.185-193
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• 1992

The purpose of this study was to evaluate the prevalence and distribution of tooth number anomaly by means of the analysis of panoramic radiographs in 6,531 patients visited the Dental Infirmary of Kyungpook National University Hospital from January 1983 to May 1992. The results were as follows: 1. The prevalence of congenitally missing teeth except third molar was revealed to be 10.8%, and there was a hihger prevalence in females(44.6%) than in males(55.4%). Mandibular 2nd premolars(23.2 %) were absent most frequently, followed by maxillary lateral incisors(18.4 %), mandibular lateral incisors(18.3%), and maxillary second premolars(15.4 %) in descending order of frequency. As to the number of congenitally missing teeth, the percentage of missing one tooth was 48%, missing two teeth was 35.4 %, missing three teeth was 6.6%. 2. he prevalence of congenitally missing third molars was revealed to be 39.7%. There was a higher prevalence n the maxilla(60.3%) than in the mandible(39.7%). Maxillary right 3rd molars(30.6%) were absent most frequently, followed by maxillary left 3rd molar(29.7%), mandibular right 3rd molar(202%), mandibular left 3rd molar(19.5%) in descending order of frequency. 3. The prevalence of supernumerary teeth was revealed to be 4.2%, and there was a higher prevalence in males(65.7%) than in females(34.3 ). They were ound most frequently in maxillary central incisor area(64.8%), followed by maxillary lateral incisor area(132%), posterior area of maxillary third molar(8.7%) in descending order of frequency. As to the number of supernumerary teeth; The percentage of one supernumerary tooth was 79.9%, two supernumerary teeth was 8.9%, three supernumerary teeth was 1.2 %.

• Restorative Dentistry and Endodontics
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• v.7 no.1
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• pp.59-63
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• 1981

Ninety four human mandibular third molars were chosen to study the anatomy of the root canal. The experimental teeth were injected with china ink, decalcified, cleared and used in study, in vitro, to determine the number of root, the number of root canals, canals per root, frequency and location of transverse anastomoses, frequency and location of lateral canals and frequency of the apical deltas. The results were as follows: 1. Most of the teeth showed two canals, but 17.0% of the teeth were found to have one canal, 17.0% of them three canals, 3.2% of them four canals and l.1% of them five canals. 2. In so far as observing one canal per root, 17.0% of the teeth were found to have one canal in single-rooted tooth, 48.9% of them in mesial root and 58.5% of them in distal root. 3. In roots with two or three canals, the separated apical foramen appeared in 55.6% in single-rooted tooth, 64.3% in mesial side and 80.0% in distal side, and the common apical foramen appeared in 44.4% in single-rooted tooth, 35.7% in mesial side and 20.0% in distal side. 4. Of the two root canals in one root, 19.1% of the canals were found to have transverse anastomoses and were usually located in the apical third of the root. 5. 63.8% of 94 teeth were found to have lateral canals, and ramifications were mainly located in the apical third of the root.

• Anatomy and Cell Biology
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• v.56 no.4
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• pp.474-481
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• 2023

The dental characteristics created by acquired dental treatments can be used as age estimators. This pilot study aimed to analyze the correlation between the number of teeth observed for dental characteristics and chronological age and to develop new non-invasive age estimation models. Dental features on panoramic radiographs (420 radiographs of subjects aged 20-89 years) were classified and coded. The correlation between the number of teeth for each selected code (codes V, X, T, F, P, and L) and age was observed, and multiple regression was performed to analyze the relationship between them. Eleven regression models with various combinations of dental sextants were presented. The model with the data from both sides of the posterior teeth on both jaws showed the best performance (root mean square error of 14.78 years and an adjusted R² of 0.461). The model with all teeth was the second-best. Based on these results, we confirmed statistically significant correlations between certain dental features and chronological age. We also observed that some regression models performed sufficiently well to be used as adjunctive methods in forensic practice. These results provide valuable information for the design and performance of future full-scale studies.