• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.6 no.1
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• pp.51-58
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• 1976

The study was performed to investigate the thickness of lamina dura of the human teeth in normal condition, which obtained from the intraoral roentgenograms of the 1200 cases taken by bisecting technique. All films were divided into the different ages, the different sexes, and the different location of the different teeth. The obtained results were as follows: 1. With advancing age in both sexes, the lamina dura tends to become thinner as following. (equation omitted) 2. Generally, the alveolar crest is the thickest among the root surfaces, and apex, midroot followed, and the average thickness of the posterior teeth is thicker than that of the anterior teeth. 3. The mean value of the whole maxillary teeth is larger than the one of the whole mandibular teeth. 4. On the whole cases, the differences of male and female is about 0.019㎜, which is not a significant differences.

• The Journal of the Korean dental association
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• v.11 no.5
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• pp.313-316
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• 1973

970 children visited attached hospital, S.N.U, were taken orthopantomograph. Of those children, there were 14 patients who have primary fused teeth. The author observed those cases and got following results. 1) Incidence of primary fused teeth was higher in female. 2) In the order of frequency, fused teeth of mandibular right primary lateral incisor and canine were 9 and that of mandibular left primary lateral incisor and canine were 4, and there was only one case in maxillary. 3) 13 cases showed the congenital absence of lateral incisor of the corresponding permanent teeth. 4) Incidence of fused teeth was 1.44%.

• International Journal of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.280-286
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• 2024

In this paper, layered UNet with warmup and dropout tricks was used to segment teeth instantly by using data labeled for each individual tooth and increase performance of the result. The layered UNet proposed before showed very good performance in tooth segmentation without distinguishing tooth number. To do instance segmentation of teeth, we labeled teeth CBCT data according to tooth numbering system which is devised by FDI World Dental Federation notation. Colors for labeled teeth are like AI-Hub teeth dataset. Simulation results show that layered UNet does also segment very well for each tooth distinguishing tooth number by color. Layered UNet model using warmup trick was the best with IoU values of 0.80 and 0.77 for training, validation data. To increase the performance of instance segmentation of teeth, we need more labeled data later. The results of this paper can be used to develop medical software that requires tooth recognition, such as orthodontic treatment, wisdom tooth extraction, and implant surgery.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.8 no.1
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• pp.23-27
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• 1978

The purpose of the present investigation is to determine how frequently radiopaque zones are seen on standard intraoral films and to research some other things about radiopaque zones. This study obtained the following results: 1. According to the standard intraoral films of the charts that were kept at the Dept. of Oral Diagnosis in Seoul National University Hospital, radiopaque zones were found in the rate of 4.1% among 1150 cases of amalgam-restored teeth that were treated at least two years ago. 2. Out of teeth that possessed radiopaque zones, 38.3% had radiolucent area between amalgam restoration and radiopaque zone. 3. Out of teeth that possessed radiopaque zones, 36.2% had cement base between amalgam restoration and radiopaque zone. 4. Out of teeth that possessed radiopaque zones, no tooth had periapical radiolucency. 5. Radiopaque zones were found more frequently in the mandibular teeth than the maxillary teeth. 6. According to the result of direct x-ray taking of 50 teeth that were treated at least 2 years ago, 6% had radiopaque zone.

• Journal of Technologic Dentistry
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• v.9 no.1
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• pp.51-55
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• 1987

One of the primary advantages of acrylic resin teeth is their ability to bond chemically to the denture base resins. Fracture od acrylic resin teeth from a maxillary denture, however, is not uncommon. Bonding failures have been attributed to faulty boil-out procedures that fail to eliminate all traces of wax from the ridge lap surfaces of the teeth and to contamination of the ridge lap surface by careless application of tinfoil substitute. Attempts to increase the strength of the bond between acrylic resin teeth and heat-cured denture base resin include grinding the glossy ridge lap surface (in fluid system), painting the ridgelap surface of the teeth with monomer-polymer solution, and cutting retention grooves in the ridge lap surface of the teeth. This latter method has been tested by applying a tensile force in a labial direction to the incisal part of the lingual surface of the acrylic resin teeth. A progressive shear compressive load was applied at an angle to the lingual surface of acrylic resin teeth bonded to denture base acrylic resin. No statistically singificant advantage was derived by preparing retention grooves of different shapes in the ridgelap surface of the denture teeth.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.33 no.1
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• pp.1-8
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• 1997

To find the tooth selectivity of the dredge for catching the ark shell Scapharca broughtonii, the probabilities of the ark shells which are not sifting through the gaps between teeth were calculated for the various shell lengths. Considering that these probabilities are in proportion to the relative catching efficiencies, selectivity curves for the ark shell dredge were estimated for the various gaps between teeth. The ratio of the shell length of ark shell to the distance between teeth indicating the relative catching efficiencies of 0%, 50%, 100% respectively, were calculated by using these selectivity curves, and the values were 1.00, 1.32, 1.54 in the distance of 4.0cm between teeth and then, the ratios showed a slight tendency to decrease as the distance between teeth increased in the relative catching efficiency of 100%, In addition, the range of shell length for catching, that is, the range of selective shell length by the distance between teeth was 0.54 in the distance of 4.0cm between 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.

• Restorative Dentistry and Endodontics
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• v.16 no.2
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• pp.182-188
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• 1991

The purpose of this study was to clarify the effect of intracana1 medication on the clinical symptoms and the number of visits before canal filling in endodontic treatment The experimental teeth was divided into three groups. The teeth of group 1 was irrigated with saline solution and the teeth of group 2 was irrigated with sodium hypochlorite during biomechanical preparation. The intracanal medicament was not applied in the canals of group 1 and group 2. The teeth of group 3 was irrigated with sodium hypochlorite and hydrogen peroxide during canal enlargement and applied formocresol as intracanal medicament after drying the root canals with paper points. The incidence of interappintment pain and percussion pain after 1 st visit and the number of appointments before canal filling was examined, and the results was statistically compared. The following results were obtained. 1. The incidence of interappointment pain and percussion pain and the number of visits before canal filling was not effected by the types of irrigant and the use of the intracanal medicament 2. There was no significant difference in the incidence of interappintment pain arid percussion pain and the number of appointement before canal filling between vital teeth and non vital teeth, and also between single rooted teeth and multirooted teeth. 3. The use of formocresol as intracanal medicament was not able to aid the elimination of clinical symptoms and to decrease the number of appointment before canal filling.

• Journal of Oral Medicine and Pain
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• v.6 no.1
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• pp.5-8
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• 1981

The author had sellected stone models of upper premolar teeth from 20 age to 60 ages in male, and studied the attrition pattern of upper premolar teeth having attention to teeth cups on the stone model. All of the attrition patterns were divided (into) 14 forms. The results were as follows : 1. Attrition patterns of upper premolar teeth were divided into 14 forms. 2. Being compared with age group, early attrition pattern (M) showed decreasing tendency and late attrition pattern (A) showed incresing tendency by aging.

• Journal of Oral Medicine and Pain
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• v.20 no.1
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• pp.217-228
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• 1995

For the purpose of estimating the sex and age in the remains of Catholic martyrs, the authors investigated size, shape and attrition of teeth, morphology of pulp cavity, and the changes of jaws. The 22 teeth, upper and lower jaws, the 23 teeth, upper and lower jaws, the 6 teeth and the 1 tooth were referred from The Pusan Research Institute for Church History in Pusan Catholic Parish. The results were as follows : 1. The 22 teeth, upper and lower jaws presumed to be Lee, Kwan Bok were evaluated to be in the latter half of female thirties. 2. The 23 teeth, upper and lower jaws presumed to be Kim, So ja, Maria were evaluated to be in the middle of male thirties. 3. The 6 teeth presumed to be lee, Jung Suk were evaluated to be in the earlier half of male forties. 4. The 1 tooth presumed to be Lee, Sam jo was evaluated to be in the latter half of male forties.