• Journal of the korean academy of Pediatric Dentistry
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• v.11 no.1
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• pp.25-39
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• 1984

The author has sought to determine the time and the sequence of permanent teeth eruption in Korean children. The study group consisted of 15,671 healthy children (male 8,015 ; female 7,656) aged 5-13 years old who lived in Seoul or Cheongju. The results were as follows : 1. The eruption times of permanent teeth were 0.45 years earlier in females than in males. 2. The ages corresponding to $ER_{50}$ of permanent teeth were as follows : In Maxilla 1) central incisor was 7.37 yrs 2) lateral incisor was 8.50 yrs 3) canine was 10.83 yrs 4) 1st premolar was 10.30 yrs 5) 2nd premolar was 11.09 yrs 6) 1st molar was 6.49 yrs 7) 2nd molar was 12.79 yrs In Mandible 1) central incisor was 6.40 yrs 2) lateral incisor was 7.41 yrs 3) canine was 10.18 yrs 4) 1st premolar was 10.26 yrs 5) 2nd premolar was 11.15 yrs 6) 1st molar was 6.32 yrs 7) 2nd molar was 12.05 yrs 3. The eruption sequence of permanent teeth by Z-test was as follow: In Male 1st : Mandibular 1st molar, and Mandibular central incisor 2nd : Maxillary 1st molar 3rd : Maxillary central incisor 4th : Mandibular lateral incisor 5th : Maxillary lateral incisor 6th : Mandibular canine, Maxillary and Mandibular 1st premolar 7th : Maxillary canine 8th : Maxillary and Mandibular 2nd premolar 9th : Mandibular 2nd molar 10th : Maxillary 2nd molar In Female 1st : Mandibular 1st molar, and Mandibular central incisor 2nd : Maxillary 1st molar 3rd : Mandibular lateral incisor, Maxillary central incisor 4th : Maxillary lateral incisor 5th : Mandibular canine, Maxillary and Mandibular 1st premolar 6th : Maxillary canine 7th : Maxillary and Mandibular 2nd premolar 8th : Mandibular 2nd molar 9th : Maxillary 2nd molar 4. The corresponding permanent teeth in the mandible generally erupted earlier than the corresponding permanent teeth in the maxilla by an average of 0.73 years, but the mean eruption time of mandibular 1st premolars was almost the same as those of maxillary 1st premolars, and the mean eruption time of mandibular 2nd premolars was 0.06 years later than those of maxillary 2nd premolars. 5. There is no significant difference between left and right arch in the eruption time and sequence. 6. Generally, the ages of permanent teeth eruption tended to be earlier than those of Dr. Cha's data from 1963.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.34 no.6
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• pp.432-439
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• 2012

Purpose: The aim of this study was to investigate the blood supply to the maxillary sinus in Koreans using computed tomography of the lateral wall of the sinus, and to analyze the data according to demographic data, and to compare our results with previously published research. Methods: One hundred and three patients (males 51, females 52) who visited the dental clinic were evaluated. We investigated the canals with cone-beam computed tomography, and measured the diameter and length from the bony notch of the vascular canal at the lateral wall of the sinus to each of the reference planes. Results: Most types of vascular canal were type I & II (total 72.2%) which were driving through inside the sinus wall. Type IV, V were frequently investigated in 1st premolar and 2nd molar. Mean height; from anterior nasal spine-posterior nasal spine plane to vascular canal was 5.56 mm in 1st premolar, 2.11 mm in 2nd premolar, 0.98 mm in 1st molar, 4.32 mm in 2nd molar; from the basal layer of the sinus was 4.93 mm in 1st premolar, 5.00 mm in 2nd premolar, 6.05 mm in 1st molar, 7.91 mm in 2nd molar; and from alveolar crest, 20.80 mm in 1st premolar, 16.57 mm in 2nd premolar, 14.01 mm in 1st molar, 16.17 mm in 2nd molar. The mean height of the vascular canal of each reference plane showed no significant difference between sex, site (left or right) and age. The mean diameters of the canals were 1.76 mm in male, and 1.50 mm in female. Diameter decreased with age, and tooth site (from 1st premolar to 2nd molar). Conclusion: These results show that the mean diameter of the vascular canal of the maxillary sinus varies according to age, sex, and tooth site, but that the mean height of canal had no significant difference based on these three factors.

• Journal of Periodontal and Implant Science
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• v.27 no.1
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• pp.235-248
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• 1997

The purpose of this study was to investigate the width of attached gingiva of 414 subjects with healthy gingiva, or early stage of gingivitis. We compared the differences according to the tooth location, age (Yonger group : $14{\sim}30$, Older group : $31{\sim}67$) and gender. In addition, we compared the width of attached gingiva in the subjects with less than 2 sites of gingival recession($Re{\leq}2$) and the subjects with more than 3 sites of gingival recession($Re{\geq}3$) to study the relationship between the gingival recession and the width of attached gingiva. The results were as follows : 1. The width of keratinized gingiva was widest in maxillary incisors($5.3{\pm}1.4mm$) and narrowest in mandibular right 1st bicuspid and mandibular right and left 2nd molars($3.5{\pm}1.1mm$). 2. The width of attached gingiva was widest in maxillary right central incisor($3.8{\pm}1.5mm$) and narrowest in mandibular right 2nd molar($1.2{\pm}1.0mm$). 3. In the comparison between the age groups, the width of keratinized in older group was significantly (p<0.05) wider than that in younger group in maxillary right and left 1st bicuspids, mandibular right and left 1st and 2nd molars, maxillary right and left cuspids and mandibular right 1st bicuspid. There was no significant difference in the width of attached gingiva between the two groups except for maxillary right and left 1st molars and maxillary left 2nd molar. 4. In the comparison between male group and female group, in maxillary right and and left lateral incisors and cuspids, mandibular right and left cuspids and 1st bicuspids, the width of attached gingiva in female was significantly(p<0.05) wider than that in male group. 5. In the comparison between the Re 3 group and Re 2 group, there was no significant difference except for maxillary right and left 2nd molars and maxillary left 1st molar. 6. The frequency of gingival recession was m the order of mandibular right 1st bicuspid(16.6%), maxillary right 1st bicuspid(13.7%), maxillary and mandibular left 1st bicuspids (13.4%), mandibular left cuspid (10.5%), maxillary left and mandibular right cuspids(10.1%) and maxillary right cuspid(7.9%).

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.13 no.1
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• pp.107-115
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• 1983

This study was performed in order to analyse the morphology of maxillary sinus on orthopantomogram. The author anlaysed the anterior-posterior width of mesial wall, the extension of anterior margin in maxillary sinus and the interrelation between the root apex of maxillary 1st molar and sinus floor. The films consisted of 514 orthopantomograms divided into three groups ranging the 3rd decade, 4th and 5th decade and 6th decade. The obtained results were as follows: 1. The mean dimensions of the anterior - posterior width of mesial wall were 43.81±4.55㎜ for male and 43.80±4.49㎜for female in the right of maxillary sinus, 43.75±74㎜ for male and 43.37±3.92㎜ for female. 2. With age, the dimensional change of the anterior - posterior width of mesial wall in maxillary sinus was not observed. 3. The extension order of anterior margin of the maxillary sinus was distal to canine side, 1st premolar mesial side, canine mesial side, and 1st premolar distal side. 4. In the distance between the root apex of upper 1st molar and the maxillary sinus floor, the degree of closeness was more increased in the older-aged group than in the younger-aged group.

• The Journal of the Korean dental association
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• v.10 no.7
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• pp.413-415
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• 1972

The author had a case report of right maxillary molar tooth root apex cyst involving maxillary sinus, which was misdiagnosed maxillary sinusitis or some cancer. Right maxillary 2nd premolar, 1st molar, & 2nd molar tooth involved root apex cyst was extracted and curetted.

• The korean journal of orthodontics
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• v.45 no.5
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• pp.236-244
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• 2015

Objective: The aim of this study was to investigate three-dimensional molar displacement after distalization via miniscrews and a horizontal modification of the trans-palatal-arch (TPA). Methods: The subjects in this clinical trial were 26 Class II patients. After the preparation of a complete set of diagnostic records, miniscrews were inserted between the maxillary 2nd premolar and 1st molar on the palatal side. Elastic modules connected to the TPA exerting an average force of 150-200 g/side parallel to the occlusal plane were applied. Cone-beam computed tomography was utilized to evaluate the position of the miniscrews relative to the adjacent teeth and maxillary sinus, and the direction of force relative to molar furcation. The distances from the central point of the incisive papilla to the mesiopalatal cusps of the 1st maxillary molars and the distances between the mesiopalatal cusps of the left and right molars were measured to evaluate displacement of the maxillary molars on the horizontal plane. Interocclusal space was used to evaluate vertical changes. Results: Mean maxillary 1st molar distalization was $2.3{\pm}1.1mm$, at a rate of $0.4{\pm}0.2mm/month$, and rotation was not significant. Intermolar width increased by $2.9{\pm}1.8mm$. Molars were intruded relative to the neighboring teeth, from 0.1 to 0.8 mm. Conclusions: Distalization of molars was possible without extrusion, using the appliance investigated. The intrusive component of force reduced the rate of distal movement.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.1 no.1
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• pp.5-11
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• 1971

The author has observed the orthopantomograms of the maxillary sinus which were taken by special exposure method to study mesiodistal dimension, shape, symmetrical relationship, bony septum of the maxillary sinus and relationship between upper. 1st molar and the maxillary sinus, that were selected 56 cases of 23 to 27 years old male, who have good. systemic conditions and no missing teeth on upper posterior molar in normal occlusion, and obtained following conclusions: 1. Mesiodistal dimensions of the maxillary sinus are shown as follows; The mean of left dimension is 50.94±8.34㎜ and of right dimension is 49.50±9.87㎜. 2. To the shape of the maxillary sinus, V or U shape are 33cases(29.5%) and W shape are 77 cases(70.5%). 3. In the ralationship between upper 1st molar and floor of the maxllary sinus, superimposition are 62 cases (55.36%) and aproach are 50 cases (44.64%). 4. In the right and left symmetrical relationship of the maxillary sinus, symmetry are 37cases (66.07%) and asymmetry are 19 cases (33.93%). 5. The bony septums in the maxillary sinuses revealed that presence of bony septums are 29 cases (25.8%) and absence are 83 cases (74.11%).

• The korean journal of orthodontics
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• v.39 no.6
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• pp.354-361
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• 2009

Objective: Miniscrews are widely used in orthodontic treatment for the purpose of anchorage control. Maximum anchorage can be acquired by the use of miniscrews. Maxillary miniscrew has many clinical advantage for orthodontic treatment. Maxillary sinus, tooth root can be an obstacle for maxillary miniscrew installation. The purpose of this study was to find the safest area and direction of miniscrew insertion in consideration of the maxillary sinus. Methods: The maxillary sinus area of 40 patients (20 male, 20 female) was measured using 3D computed tomography and 3D reconstruction program. Results: The maxillary sinus floor was located most inferiorly between the 1st molar and 2nd molar and located most superiorly between the 1st premolar and 2nd premolar. Buccal bone thickness from the maxillary sinus is significantly thicker between the 1st molar and 2nd molar and significantly thinner between the 1st premolar and 2nd premolar. The area between the 1st premolar and 2nd premolar has a significantly longer vertical distance from CEJ to sinus in consideration of buccal bone thickness. Conclusions: Considering maxillary bone thickness, the posterior area has advantages over the anterior area for installing miniscrews safely and preventing perforation.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.14 no.1
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• pp.17-26
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• 1984

The purpose of this study was radiographic analysis of the morphology of maxillary sinus in adolescents and adults. In order to analize the morphology of maxillary sinus in view point of anteroposterior width of medial wall, vertical distance between antral floor and nasal floor level, anterior extension, distance between antral floor and maxillary 1st molar apex, and types of lower border of maxillary sinus, specialized maxillary projection and periapical view with paralleling technique was taken. The author examined orthopantomograms and intraoral standard views taken from 400 adolescents and adults ranged 15-65 year-old. The obtained results were as follows: 1. The antero-posterior width of medial wall of maxillary sinus was 32.80mm in 15-19 year-old group, 33.86㎜ in 20-24 year-old group, 34.09㎜ in 25-29 year-old group, and 33.67㎜ in 30-65 year-old group, and the left maxillary sinus was somewhat smaller than the right. 2. The vertical distance between antral floor and nasal floor level was 8.49㎜ in 15-19 year-old group, 9.05㎜ in 20-24 year-old group, 8.95㎜ in 25-29 year-old group, and 8.32㎜ in 30-65 year-old group. 3. The order of anterior extension of maxillary sinus were distal half of canine, mesial half of canine, mesial half of 1st premolar, and distal half of 1st premolar. 4. The distance between antral floor and maxillary 1st molar were 4.36㎜ in 15-19 year-old group, 4.77㎜ in 20-24 year-old group, 3.58㎜ in 25-29 year-old group, and 2.33㎜ in 30-65 year-old group. 5. The order of the types of lower border of maxillary sinus were entire downward type, close type, partially downward type, waving type, separating type, and indistinct. In the types of antral floor, there was a tendency to increase the seperating type with age.

• Restorative Dentistry and Endodontics
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• v.7 no.1
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• pp.25-31
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• 1981

One of the most important factors for successful endodontic therapy is an accurate length determination of physiological root apex. Some methods suggested for the measurement of root canal length, include digital-tactile sense and roentgenographic technique with measuring wire, scale and grid. But these methods do not derermine an accurate working length to physiological root apex. Recently electronic measuring devices are used to locate the physiological root apex in root canal length determination and these devices are accepted as an effective apparatus. The 89 patients (116 teeth, 144 canals) among the out-patients of Yonsei University Dental Infirmary, who had had an endodontic treatment in the Department of Operative Dentistry, were measured by the Root-Canal Meter$^{(R)}$ as an electronic device, and radiographs to determine the distribution and location of physiological root apex, then the following results were made: (1) Range of ${\pm}$1mm from the radiographic root apex were present in 88.88% (128 canals) of the subjects. (2) Physiological root apex and radiographic root apex were coincided in 31.94% (46 canals) of the subjects. (3) The actual length of the physiological root apex of the teeth were as follow; A : in the maxillary central incisor : 0.46mm B : in the maxillary lateral incisor : 0.44mm C : in the maxillary canine : 0.44mm D : in the maxillary 1st premolar : a) Buccal : 0.59mm b) Lingual : 0.34mm E : in the maxillary 2nd premolar : 0.54mm F : in the maxillary 1st molar : a) Mesio-buccal : 0.50mm b) Disto-buccal : 0.42mm c) Lingual : 0.56mm G : in the mandibular central incisor : 0.62mm H : in the mandibular lateral incisor : 0.45mm in the mandibular canine : 0.54mm J : in the mandibular 1st premolar : 0.47mm K : in the mandibular 2nd premolar : 0.34mm L : in the mandibular 1st molar : a) Mesio-buccal : 0.54mm b) Mesio-lingual : 0.31mm c) Distal : 0.37mm.