• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.1
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• pp.122-134
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• 2000

The aim of this study is (1) to establish the baseline information concerning the width of keratinized gingiva, depth of gingival sulcus and width of attached gingiva on the buccal surface of the teeth: and (2) to determine the relationship between the above values and tooth eruption: and (3) to estimate the frequency of mucogingival problems. The results were as follows; 1. The mean width of attached gingiva of the children aged $6\sim12$ proved to be wider in the maxilla than in the mandible. Of the primary teeth, the widest width was found in the areas of maxillary primary lateral incisors and maxillary primary canines(3.50mm and 3.55mm). The narrowest was noted in the area of mandibular first primary molars(1.34mm) In the permanent dentition, the greatest width was found in the areas of maxillary permanent lateral incisors (3.00mm). The narrowest was noted in the area of mandibular first premolars(0.55mm). 2. In the primary dentition, the width of attached gingiva of primary canines and first and second primary molars became wider from the age of six as the age increased. In the permanent dentition of the boys, only mandibular central incisors and maxillary first molars showed the tendency towards increase in the width of attached gingiva with increasing age. In the permanent dentition of girls, central and lateral incisors of both jaws and maxillary first molars showed statistically significant increase in the width of attached gingiva with increasing age(p<0.05). 3. At the age of tooth change, the attached gingiva of primary teeth were almost wider than those of successive permanent teeth (p<0.05). 4. During the period of 6 to 12 years of age, the width of keratinized gingiva and the depth of gingival sulcus of permanent tooth at the age of twelve were larger than those of primary tooth at the age of six (p<0.05). 5. The maximum in the frequency of mucogingival problems was found in the areas of upper and lower first primary molars of primary dentition, and in the upper and lower first premolars of permanent dentition regardless of sex. The frequency was higher in primary teeth than in the corresponding successive permanent teeth These teeth showed tendency towards increase in mucogingival problems with age.

• Journal of Oral Medicine and Pain
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• v.38 no.2
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• pp.143-147
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• 2013

Mouth opening limitation is generally caused by masticatory muscle or temporomandibular joint pain, disc dislocation without reduction, adhesion or ankylosis of the temporomandibular joint, and muscle contracture. But otorhinolaryngologic disease, neurologic and vascular disease, tumor, inflammation and infection may cause pain and mouth opening limitation which mimics temporomandibular disorders. Re-evaluation for possibilities of inflammation, infection and tumor should be in cases that do not show symptom improvement or appear with continuous aggravation despite of proper treatment. In this case, we report of medial pterygoid muscle pain and mouth opening limitation caused by periapical abscess of third molar spread to the pterygomandibular space.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.3
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• pp.312-319
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• 2020

Precocious puberty (PP) is defined as the early development of secondary sexual characteristics (before the ages of 8 years in girls and 9 years in boys). The aim of this study is to identify characteristics of the dental maturity in girls with PP that discriminate them from normal healthy girls. This study included 99 girls aged 6 - 8 years with PP and 99 girls without past medical history of same chronological age (control group). The study was performed on 198 panoramic radiographs (99 PP girls, 99 control group girls). Demirjian method was used to evaluate the panoramic radiographs and determine dental maturity. Difference in dental maturity score and tooth formation stages between the two groups were analyzed. The PP group showed significant higher maturity score than control group. Among mandibular teeth, mandibular 2nd premolar and 2nd molar were significantly more mature in the PP group than control group. Logistic regression analysis showed that mandibular 2nd molar was only significant predictor for PP girls.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.4
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• pp.693-702
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• 2005

Accurate timing and sequence of eruption of permanent teeth are indicies of growth and essential for pediatric dentistry and pediatric clinical orthodontics. From the children brought to the Yonsei Dental Hospital during 2001 to 2003, 654 boys and 542 girls, ranging in age from five to fourteen years, were selected and analysed. The following was concluded. 1. Eruption time of maxillary teeth is 6.81 years in boys, 6.78 years in girls for central incisor, 8.30 years in boys, 7.98 years in girls for lateral incisor, 10.28 years in boys, 10.04 years in girls for canine, 9.74 years in boys, 9.90 years in girls for first premolar, 10.87 years in boys, 10.41 years in girls for second premolar, 6.25 years in boys, 6.54 years in girls for first permanent molar, 12.21 years in boys, 12.03 years in girls for second permanent molar 2. Eruption time of mandibular teeth is 6.00 years in boys, 6.06 years in girls for central incisor, 6.99 years in boys, 6.74 years in girls for lateral incisor, 9.83 years in boys, 9.17 years in girls for canine, 9.92 years in boys, 9.75 years in girls for first premolar, 10.66 years in boys, 10.39 years in girls for second premolar, 5.99 years in boys, 5.75 years in girls for first permanent molar, 11.92 years in boys, 12.17 years in girls or second permanent molar. 3. The following eruption sequence was observed the first permanent molar erupted first, followed by the central incisor, the lateral incisor, the first premolar, the canine, the second premolar and the second permanent molar in the maxilla. The first permanent molar erupted first, followed by the central incisor, the lateral incisor, the canine, the first premolar, the second premolar and the second permanent molar in the mandible.

• The korean journal of orthodontics
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• v.39 no.5
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• pp.300-309
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• 2009

Objective: The purpose of this study was to evaluate the correlation between menton deviation and dental compensation in facial asymmetry. Methods: Tooth axis and distance of first molar and canine to the reference plane were investigated by cone-beam computerized tomography. The subjects consisted of 50 patients with asymmetric mandibles (male 21, female 29, mean age 24.3 years). Control groups were also assessed (male 11, female 9, mean age 25.6 years). Nine measurements (5 linear measurements and 4 angular measurements) were measured in order to evaluate the correlation between menton deviation and the linear and angular difference of first molar and canine in the deviated and none-deviated sides using the defined MPR images. The differences between deviated and non-deviated side, according to menton deviation, were statistically analyzed using stepwise multiple regression analysis. Results: From the result, Menton deviation was negatively correlated with mandibular first molar's angular measurement (${\Delta\angle}LM6$-Mn plane (dev.-ndev.)) and positively with maxillary fist molar's angular measurement (${\Delta\angle}UM6$-FH plane (dev.-ndev.)) (p < 0.01). Two angular measurements (${\Delta\angle}LM6$-Mn plane (dev.-ndev.), ${\Delta\angle}UM6$-FH plane (dev.-ndev.)) explained the variability in menton deviation with a significant $r^2$ value of 0.589. Conclusions: This study suggests that the tooth axis of upper and lower first molars leans towards the deviated side of Menton when there is mandibular asymmetry with Menton deviation.

• The korean journal of orthodontics
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• v.27 no.5 s.64
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• pp.761-770
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• 1997

71 Class I malocclusion samples were selected and they were divided into premolar-extraction and non-extraction groups. Vertical and horizontal cephalometric evaluations on dental and soft tissue measurements were done before and after treatment. Also, treatment results in adolescent patients and adult patients were compared. The following conclusions were obtained: 1. In comparison of extraction and non-extraction groups, all the dental and soft tissue measurements, with exception of SN-MP angle, upper lip to E-line, vertical movement of upper first molar, md horizontal movement of lower first molar, showed statistically significant differences. 2. In comparison of extraction and non-extraction groups of adolescent samples, there were statistically significant differences in upper and lower incisor inclinations, horizontal dental movements from vertical reference line, positional changes in upper and lower lips, and mesial movements of upper first molar. 3. In comparison of extraction and non-extraction groups of adult samples, there were statistically significant differences in upper and lower incisor inclinations, horizontal dental movements from vertical reference line, positional changes in upper and lower lips from I-line and vertical reference line, vertical height of upper first molar, and mesial movement of lower first molar. 4. There was no statistically significant difference in SN-MP angle between extraction and non-extraction groups of both adolescent and adult samples.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.3
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• pp.262-269
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• 2011

Ameloblastic fibroma is rare true benign mixed odontogenic tumor. Most of these tumors occur in the posterior region of the mandible under 20 years of age. It develops generally associated with unerupted tooth and grows slowly on the surface of alveolar bone, therefore interferes normal tooth eruption. These lesions rarely showing a little bony expansion, are usually asymptomatic and are discovered incidentally on routine dental exam. It is similar to amleoblastic fibroodontoma and ameloblastic fibrodentinoma clinically and roentgenographically but represents no dental hard tissue formation histologically. Enucleation and curettage of surrounding bone are generally recommended options for treatment. Even though there are some reports of recurrence and malignant transformation and more aggressive treatment options like block resection are suggested sometimes, but in most cases, recurrence is unusual because it is well encapsulated and easily separated from adjucent bony socket. In these cases, we did conservative treatment such as enucleation and curettage to the patients who were visited for ameloblastic fibroma associated with delayed eruption of lower first molar. After regular check-ups, we found relatively natural eruption process of combined teeth.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.2
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• pp.157-168
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• 2008

Statement of problem: Over the past two decades, implant supported fixed prosthesis have been widely used. However, there are few studies conducted systematically and intensively on the splinting effect of implant systems in mandible. Purpose: The purpose of this study was to investigate the changes in stress distributions in the mandibular implants with splinting or non-splinting crowns by performing finite element analysis. Materials and methods: Cortical and cancellous bone were modeled as homogeneous, transversely isotropic, linearly elastic. Perfect bonding was assumed at all interfaces. Implant models were classified as follows. Group 1: $Br{{\aa}}nemark$ length 8.5mm 13mm splinting type Group 2: $Br{{\aa}}nemark$ length 8.5mm 13mm Non-splinting type Group 3: ITI length 8.5mm 13mm splinting type Group 4: ITI length 8.5mm 13mm Non-splinting type An load of 100N was applied vertically and horizontally. Stress levels were calculated using von Mises stresses values. Results: 1. The stress distribution and maximum von Mises stress of two-length implants (8.5mm, 13mm) was similar. 2. The stress of vertical load concentrated on mesial side of implant while the stress of horizontal load was distributed on both side of implant. 3. Stress of internal connection type was spreading through abutment screw but the stress of external connection type was concentrated on cortical bone level. 4. Degree of stress reduction was higher in the external connection type than in the internal connection type.

• The korean journal of orthodontics
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• v.17 no.2
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• pp.321-333
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• 1987

The purpose of this study was to observe the changes of the lower 3rd molars following the extraction of the lower 2nd molars by Lateral Cephalograms and Orthopantomograms. The subjects consisted of twenty malocclusion, 7 males 13 females, were 19 year 5 month old at the removal of the lower 2nd molars, 19 year 1 month old at the end of the orthodontic supervision after the removal of the lower 2nd molars (mean age) The obtained results were as follows, 1 It is recommended to extract the lower 2nd molars when the lower 3rd molars are Nolla's Stage 4 or 5 2 With the pre-extraction variables obtained by factor analysis, it was possible to predict the long axis of the lower 3rd molars after 2nd molar extraction. 3 There were no impacted 3rd molars.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.3
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• pp.421-429
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• 2001

Since Non-Extraction treatment in some orthodontic case shows unstable result and unfavorable profile, extraction is selected as inevitable treatment option for the harmonious profile, facial skeleton, and the stable dentition on both arches. For the achievement of proper goal, premolars, molars, sometimes incisors or canines are selected to be extracted. The first Premolar is usually extracted for relieving the crowded dentition with which the molar relations are class I to gain stable dentition and proper profile, but often results in the depression of profile or the loss of vortical dimension. On the contrary, the extracton of the second molar helps maintaining the fullness of profile and the vertical dimension, prevents additional space closural procedures which often make the procedures complicated, relieves both anterior and posterior crowding, and substitutes the extraction fossae for newly erupting 3rd molars. From the point of recurrence, the second molar extraction procedure, therefore, is more beneficial. This cases showed the good results of second molar extraction procedures in the patients with class I crowding.