• The Journal of Korean Academy of Prosthodontics
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• v.16 no.1
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• pp.32-37
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• 1978

The purpose of this study was to apply the position, the form and the angle of the attrition in the natural maxillary central incisors shown on the labial surface to the artificial teeth in the field of prosthetic dentistry. So we should exactly alter the molds of artificial teeth in individual cases in order to make artificial teeth more natural. 226 extracted teeth of the maxillary central incisors were chosen as materials. I have exactly examined the teeth with a magnifying glass and a circular graduator under concentrated light. The observation brought me the following results: 1) The attrition was most prevailing at the range from the mesial angle to the middle part of cutting edge in the left maxillary central incisor, and distal angle of cutting edge in the right maxillary central incisor. 2) On the attrite form of both angles, the angulated form was more than 4 times as frequent as rounded form in the mesial angle, and almost equal in the distal angle. 3) On the attrite form of cutting edge, mesial attrite form including mesial angle was most frequent in the left maxillary central incisor, and distal attrite form including distal angle in the right maxillary central incisor. 4) The angle made by the labial surface and the attrite surface was about $39^{\circ}$, and more than 70% of the total examined teeth were included at the range from $31^{\circ}\;to\;50^{\circ}$. 5) None attrite form at the cutting edge was about 12% and completely attrite form at the cutting edge was about 27% of examined teeth.

• The Journal of the Korean dental association
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• v.12 no.6
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• pp.377-379
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• 1974

A rare case of two supernumerary teeth on the lingual side of the upper central incisors was observed in a 17 year old korean male. The characteristics were as follow : 1) The site of the occurrence was on the lingual side of upper central incisors. 2) The sizes of both supernumerary teeth were smaller than the normal incisor teeth and quite different from the normal incisors in the tooth shape. 3) A diastema was seen between the maxillary central incisors, and the right incisor exhibited labioversion and left incisor exhibited some mesial inclination.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.20 no.1
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• pp.79-89
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• 1990

The incidence and several characteristic features of fused and geminated teeth were studied radiographically, with full mouth periapical radiogram and pantomogram, in 4201 patients of mixed dentition and 5358 patients of permanent dentition. The obtained results were as follows: 1. The prevalence was revealed to 2.86%, 0.32%, 0.33%, and 0.06% in deciduous fused tooth, permanent fused tooth, deciduous geminated tooth and permanent geminated tooth respectively, and these anomalies were occured in female more than male. 2. Fused teeth were observed predominantly in lower anterior teeth area, especially in lateral incisor and canine region, and many cases of deciduous geminated tooth were observed in upper central incisor region. 3. Congenital missing rates of succedaneous tooth in deciduous fused teeth were 57.1 %, 85.7%, 71.0%, 69.0% in upper right and left central-lateral incisor regions, lower right and left lateral incisor-canine regions, respectively. 4. Prevalence of dental caries was 42.3%, 18.8% and 5.6% in deciduous fused, deciduous geminated and permanent fused tooth, respectively. 5. In classifying of fused and geminated teeth into 9 types, by following appearance such as number of crown, root, pulp chamber and pulp canal of those teeth, it was more favorable that Type Ⅰ(2 crown, 2 root, 2 pulp chamber, 2 pulp canal) in deciduous fused tooth and Type Ⅸ (I crown, 1 root, 1 pulp chamber, 1 pulp canal) in permanent fused tooth, deciduous and permanent geminated tooth.

• Journal of the korean academy of Pediatric Dentistry
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• v.7 no.1
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• pp.85-93
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• 1980

This study was undertaken in order to observe the prevalence of congenital dental anomalies especially that of oligodontia and supernumerary teeth in 1024 children at age from 4 to 14 years, through history taking, oral examinations, roentgenographic observations of subjects, and statistic analysis was made. The following results were obtained: 1. The prevalence of oligodontia in 1024 children was $6.45{\pm}.8$ percent with a total of 122 teeth absent in sixty-six subjects, excluding 3rd molars, and most of children (86.4%) who have congenitally missing teeth showed abscence of one or two teeth individually. 2. The teeth most frequently absent were the mandibular second premolar, maxillary second premolar, maxillary lateral incisor, mandibular central incisor, and mandibular lateral incisor in order. 3. There was no statistically significant difference found in tooth abscence in the following comparisons; .Male vs Female .Bilateral vs Unilateral .Maxilla vs Mandible .Right vs Left 4. The prevalence of supernumerary teeth in 1024 children was $4.79{\pm}.67$ percent with a total of 59 supernumerary teeth in forty-nine subjects, all of children who have supernumerary teeth showed one or two supernumerary teeth individually. 5. Statistically significant difference was found in supernumerary teeth in the comparison of male vs female, and they were more frequent in male.

• Journal of Korean society of Dental Hygiene
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• v.12 no.2
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• pp.261-273
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• 2012

Objectives : This study aims to prepare the basic data of the teeth color by measuring tooth mode using the color of the maxillary central incisor of the college students in their twenties as the dental colorimeter, and oral health and eating habit characteristics were examined. Methods : The maxillary central incisor(1 teeth) of the subjects of study as 467 students(male 89, female 378) was measured during the period from November 14, December 2 2011, so the color of total 467 teeth were examined, and oral health and eating habit characteristics were researched. Results : 1. As the results of measurement of the shade, value, hue of maxillary central incisor by the general characteristics of the subject, the major(shipbuilding information, special rehabilitation for young children) was higher at 3.3 of the shade, and the grade(1), age($$\geq_-20$$), major(beauty culture & cosmetic, occupational therapy) showed higher at +2 of the value, and the grade(1) and all major showed higher at R3 of the hue. 2. As the results of measurement of the shade, value, hue of maxillary central incisor by the oral health characteristics, the subjective teeth color(yellow) and the education of oral health(no) showed higher at 2.5 of the shade. 3. As the results of measurement of the shade, value, hue of maxillary central incisor by the eating habit characteristics of the subjects, the chocolate showed higher at 3.0 and 2.0 of the shade, and the red pepper paste showed higher at +2 and STD of the value, and the green tea showed higher at $R_3$ of the hue. Conclusions : This study demonstrates that the color of the maxillary central incisor showed differences various tendency according to the oral health and eating habit characteristics.

• Journal of Periodontal and Implant Science
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• v.36 no.2
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• pp.461-471
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• 2006

In order to achieve a satisfactory esthetic result of periodontal surgery or implant in maxillary anterior area, periodontists must be aware of normal alveolar bone anatomy. The purpose of this study was to evaluate the relationship of alveolar bone morphology to tooth shape and form. 78(mean age : 25 yrs) periodontally healthy volunteers participated in this study. Two maxillary central incisor and one lateral incisor were selected to study. With minimal local anesthesia, gutta-percha cone inserted to labial gingival sulcus of selected teeth just after bone sounding with periodontal probe. Metal ball (4mm diameter) attached to palatal fossa of central incisor. Then, periapical radiograph was taken according to long cone paralleling technique. After film scan, labial alveolar bone profile reproduced along interproximal bone and apical ends of gutta-percha cones on computer screen. By utilizing computer program, the distance from height of interproximal bone to the labial bone crest in central incisor-central incisor and central incisor-lateral incisor area was measured and converted to real distance by using vertical length of metal ball on film. After measuring crown length & width of central incisor, the 10 individuals ranked lowest GW/L ratio (crown width/length ratio) and the 10 ranked highest were selected as having a long-narrow(group N), or a short-wide(group W) form of the central incisors. Means of the distance from height of interproximal bone to the labial bone crest of group N, W were calculated and compared by means of independent t-test. The results were as follows: 1. Mean distance from the height of the interproximal bone to the labial bone crest was $3.5{\pm}0.7mm$ between two central incisor, and $2.8{\pm}0.6mm$ between central and lateral incisor. 2. Mean GW/L ratio of group N was 0.57, and group W was 0.8. Mean distance from the height of the interproximal bone to the labial bone crest of group N was higher than group W in both measured area(measurements of group N, W were $3.9{\pm0.2mm$ and $3.5{\pm}0.2mm$ between two central incisor, $3.0{\pm}0.2mm$ and $2.8{\pm}0.2mm$ between central and lateral incisor), but there were no statistically significant differences when the groups were compared. Within the limits of the present study, there was a tendency that subjects with long-narrow teeth have more scalloped alveolar bone profile than subjects with short-wide teeth in upper anterior area, but no statistically significant differences were found.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.5 no.1
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• pp.1-12
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• 1996

The arrangement of anterior artificial teeth is an important factor on the esthetics in the construction of complete dentures and prostheses. During construction of the complete denture the position of maxillary central incisor plays an important role in the arrangements of artificial teeth. The proper position of maxillary central incisor provides natural appearance of anterior teeth and the anterior reference point of occlusal plane. Many methods have been utilized to eatablish the position of the maxillary central incisor in complete denture prosthodontics. However, there has not been provided for the reference for Korean yet. This study was aimed to extablish a guide for the position of the maxillary central inciosr in Koreans. The horizontal and vertical distance between the maxillary central incisor and incisive papilla in Koreans were measured. 1. The mean value of horizontal distance from the maxillary central incisor to the incisive papilla had significant sexual difference, The average distance was 12.648mm in male and 11.385mm in female. 2. The horizontal distance of the incisive papilla had sexual difference, the average distance was 6.182mm in male and 5.622mm in female. 3. The vertical distance from the maxillary central incisor to the incisive papilla had not sexual difference, the average distance was 7.21mm. 4. The crown length of the maxillary central inciosrs from the distal interdental papilla had not sexual difference, the right central incisor was 6.40mm(mean) and the left central inciosr was 6.43mm(mean). 5. The clinical crown length of the maxillary central incisors had not sexual difference, the right central incisor 10.35mm(mean) and the left central incisor was 10.43mm(mean). 6. The shapes of the incisive papilla were pear(68.4%), oval(16%), triangular(6%), irregular(5%), rectangular(4%), and inverted pear(1%) shape.

• The Journal of Korean Academy of Prosthodontics
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• v.33 no.1
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• pp.85-97
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• 1995

The arrangement of anterior artificial teeth is an important factor on the esthetics in the construction of complete denture and prosthesis. During construction of the complete denture the position of maxillary central incisor plays an important role in the arrangements of artificial teeth. The proper position of maxillary central incisor provides natural appearance of anterior teeth and the anterior reference point of occlusal plane. Many methods have been utilized to eatablish the position of the maxillary central incisor in complete denture prosthodontics. However, there has not been provided for the reference for Korean yet. This study was aimed to extablish the position of the maxillary central inciosr in Korean. The horizontal and vertical distance between the maxillary central incisor and incisive papilla in korean were measured. The results were as follows : 1. The mean value of horizontal distance from the maxillary central incisor to the incisive papilla had significant sexual difference, the average distance was 12.648mm (male), 11.385mm(female). 2. The horizontal distance of incisive papilla had sexual difference, the average distance was 6.182mm(male), 5.622mm(female). 3. The vertical distance from the maxillary central incisor to the incisive papilla had not sexual difference, the average distance was 7.21mm. 4. The crown length of maxillary central inciosrs from the distal interdental papilla had not sexual difference, the right central incisor was 6.40mm(mean) and the left central inciosr was 6.43mm(mean). 5. The clinical crown length of the maxillary central incisors had not sexual difference, the right central incisor 10.35mm(mean) and the left central incisor was 10.43mm(mean). 6. The anatomic shapes of incisive papilla were pear(68.4%), oval(16%), triangular(6%), irregular(5%), rectangular(4%), and inverted pear(1%) shape.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.3
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• pp.407-412
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• 2002

The primary cause of missing teeth vary depending on the region. The loss of posterior teeth is mainly due to dental caries, whereas that of the anterior teeth occur primarily due to trauma at the age of standing and walking and secondarily from the rampant dental caries. Particularly, reduction of the arch length in the cases of premature loss of primary teeth may compromise the eruption of succedaneous permanent teeth. This may result in crowding and impaction of the permanent teeth, and asymmetry of arch, thus a careful consideration for space maintenance should be made in such cases. Space maintainer is required in the case of premature loss of primary posterior teeth, because space loss result from the approximate and centrifugal movement of the neighboring teeth. Generally, in the case of primary incisor, space loss occurs when 1) tooth contact is relevant, 2) crowding in primary dentition is present, and 3) a primary incisor is lost before the eruption of primary canine. Contrarily, in the case of primary dentition with interdental space, space loss will not be observed, mostly when a primary incisor is lost after the eruption of primary canine. Thus, using a space maintainer in cases of premature loss of primary incisor has been introduced primarily not for the purpose of space maintaining but for an aesthetic purpose, prevention of parafunctional oral habits such as tongue thrust, and of pronunciation. Additionally, few case studies have been reported of space loss in cases of premature loss of primary incisor. This study is to report cases of the space loss following the premature loss of primary incisors observed in children.

• The Journal of the Korea Contents Association
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• v.16 no.2
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• pp.772-781
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• 2016

This study is to set the objective criteria on maxillary incisors shade selection by using the colorimetric Shade-Eye NCC as measuring in CIE $L^*$, $a^*$, $b^*$ values, and look into the meaning by analyzing its values. We explain the purpose of this study and gotten their agreement from patients visiting the dentist, 111 people's (men 50, women 61) three teeth, the maxillary central incisor, maxillary lateral incisor, maxillary canines, total of 333 teeth colorimetry. As a result of comparing the differences in colors between cervical margin and incisal edge, ${\Delta}E^*$ of canine is shown as low as $5.81({\pm}2.98)$, followed by lateral incisor of maxilla as $6.51({\pm}3.23)$ and central incisor of maxilla $7.51({\pm}3.04)$. Females show higher luminosity(L*) than males do in all teeth- central incisor, lateral incisor and canine; in yello chroma(b*) males' central incisor is slightly higher than that of females (p<0.05). Age significantly influences the luminosity and red (a*) and yellow chroma (b*) of central incisor(L*); the luminosity(L*), and yellow chroma(b*) of lateral incisor and canine (p<0.05). Smoking doesn't significantly influence the color of natural teeth. Drinking reduces the luminosity of central incisor as well as red chroma of lateral incisor(p<0.05). A chronic illness is likely to reduce the luminosity of central incisor and lateral incisor(p<0.05).