• 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.

• The Journal of the Korean dental association
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• v.21 no.12 s.175
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• pp.1005-1010
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• 1983

To study the eruption process of the permanent tooth, esp., 1st molar, the author took 303 cases of oblique cephalogram (Male. 162 cases, Female: 141 cases) from age 3 to 8 yea old children, and observed the vertical change and axial change. The result were as follow: 1. The mesial end of upper 1st molar was closer to the occlusal plane than the distal, and they were erupting toward the occlusal plane by aging. In the case of lower 1st molar, the distal end was closer to the occlusal plane than the mesial and the occlusion showed the tendency to accord with the plane to be settled by aging. 2. Eruption rate of the upper and lower 1st permanent molar increased rapidly at 5 or 6 years of age. 3. Axial inclination of lower 1st permanent molar to the mandibular plane decreased gradually from 3 years of age, except for 6 years of age. There was some increase at 5 or 6 years of age.

• Journal of the korean academy of Pediatric Dentistry
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• v.6 no.1
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• pp.43-52
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• 1979

The purpose of this study was to finding out the relationship between the tooth calcification and eruption of the mandibular permanent teeth in Korean. This study was undertaken in 592 children at ages from 3 to 13 years who had good oral condition by means of panoramic roentgenographic analysis. The following results were obtained. 1. The mean ages of crown completion were as follows; Canine 1st. Premolar 2nd. Premolar 1st. Molar Male 6yrs. 4mos. 6yrs. 8mos. 7yrs. 6mos. 7yrs. 6mos. Female 5yrs. 11mos. 6yrs. 5mos. 7yrs. 2mos. 3yrs. 3mos. 2. Each tooth started to move toward occlusion at approximately stage 6 or after crown completion. 3. The highest increment in eruption rate was at about 1/3~1/2 completion of root and ages at 10-11 years in male, 9-10 years in female. 4. Eruption period of both sexes were as follows; Canine: 6-12years 1st. Premolar: 7-12 years 2nd. Premolar: 7-13 years 1st. Molar: 3-7 years 5. The eruption was completed before the root completion. 6. The sequence of eruption and calcification was 1st. Molar-Canine-1st. Premolar-2nd. Premolar in both sexes.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.2
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• pp.185-189
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• 2011

Tooth impaction represents the stop of eruption by clinical and radiographical disturbance in eruption path or the dislocation of tooth germ. The most common factor in tooth eruption disorders are spacial deficiency with other causes reported to be odontogenic tumors, periodontal ligament injury, etc. Impaction of the mandibular second molar is relatively rare and reported in about 3 out of 1,000 people. Because the second molars tend to erupt in a mesial direction, this situation can lead to serious problems if untreated, including dental caries, periodontal disease and root resorption of the first molar. Treatment of this problem includes, surgical repositioning and orthodontic forced eruption. Because each procedure have the definite advantages and disadvantages, and influenced by circumferential environment, these have limits for successfu1 recovery as independent treatment. In a case at St. Mary's Hospital, we performed successful correction of a horizontal impacted mandibular second molar using a miniplate skeletal anchorage system. We introduce this treatment as a valid method for an impacted second molar and consider a oromaxillofacial surgeon's role in tooth movement treatment.

• Journal of the korean academy of Pediatric Dentistry
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• v.5 no.1
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• pp.12-18
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• 1978

The author has observed the ectopic eruption pattern on oblique cephalogram of 195 children. (5years: 78, 6 years: 58, 7 years: 59). The results were as follows; 1) Making a comparison between hold type and jump type of ectopic eruption, there are 4 cases in Hold type, 5 cases in jump type. 2) Making a comparison of ectopic eruptin between male and female, there are 7 cases in male, 2 cases in female. 3) Making a comparison of ectopic eruption between right side and left side, there are 5 cases at right side, 4 cases at left side. 4) Making a comparison of ectopic eruption among 5 years to 7 years, there are 4 cases in 5 years, 3 cases in 6 years, 2 cases in 7 years. 5) The prevalence of ectopic eruption of the maxillary first molar was 4.61%. 6) Normal eruption angle of the maxillary first molar is prevailing in $80^{\circ}{\sim}85^{\circ}$.

• The korean journal of orthodontics
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• v.46 no.5
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• pp.290-300
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• 2016

Objective: This study aimed to (1) evaluate the effects of maxillary second and third molar eruption status on the distalization of first molars with a modified palatal anchorage plate (MPAP), and (2) compare the results to the outcomes of the use of a pendulum and that of a headgear using three-dimensional finite element analysis. Methods: Three eruption stages were established: an erupting second molar at the cervical one-third of the first molar root (Stage 1), a fully erupted second molar (Stage 2), and an erupting third molar at the cervical one-third of the second molar root (Stage 3). Retraction forces were applied via three anchorage appliance models: an MPAP with bracket and archwire, a bone-anchored pendulum appliance, and cervical-pull headgear. Results: An MPAP showed greater root movement of the first molar than crown movement, and this was more noticeable in Stages 2 and 3. With the other devices, the first molar showed distal tipping. Transversely, the first molar had mesial-out rotation with headgear and mesial-in rotation with the other devices. Vertically, the first molar was intruded with an MPAP, and extruded with the other appliances. Conclusions: The second molar eruption stage had an effect on molar distalization, but the third molar follicle had no effect. The application of an MPAP may be an effective treatment option for maxillary molar distalization.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.4
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• pp.556-562
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• 2009

Ectopic eruption of the maxillary first permanent molar means that the molar erupts out of the normal position and is arrested in its eruption by the second primary molar. This local eruption disturbance results in a premature atypical resorption on the distal part of the second primary molar. In most irreversible cases, the second primary molar is lost prematurely, either by spontaneous exfoliation or by extraction, In cases of doubt as to whether the eruption is of the irreversible type or not, careful radiographic observation period for a few months would be valuable in evaluating the possibilities of the tooth's freeing itself. The purpose of this study was to determine the characteristics and occurrence of the ectopic eruption of the maxillary first permanent molar. A descriptive, observational, retrospective study was done using the radiographs of 25 conseutive patients, who were in the first phase of mixed dentition. A method was designed to evaluate the amount of pathologic resorption of the second maxillary primary molar and the mesial angulation of the first permanent molar. The study showed that the most important etiologic factor was the eruption path or mesial angulation of the first permanent molars relative the chosen reference lines.

• Journal of the korean academy of Pediatric Dentistry
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• v.11 no.1
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• pp.91-101
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• 1984

The purpose of this study is to determine what influence the lesion and the premature loss of mandibular 1st deciduous molar have on the eruption of its successor, and the author devided 580 cases of orthopantomograms from age 3 to 9 years old children into 3 groups: Control Group: both side normal Study I Group: one normal and the other lesion. Study II Group: one normal and the other premature loss before 8 years old. and observed the amount of differences and the relative position in eruption between study-tooth successor and normal-tooth successor, The following results were obtained: 1. The differences in eruption between right and left mandibular 1st primary molars of Study Group were greater than those of Control Group. 2. The successors of lesioned-teeth showed more accelerated eruption than the antimeres in 40.9% and more delayed, in 22.7%. 3. The successors of premature lost-teeth showed more accelerated eruption than the antimeres in 61.7% and more delayed, in 4.3%.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.26 no.2
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• pp.181-189
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• 1996

Ameloblastic odontoma is a mixed odontogenic tumor, which is characterized as being extremely rare, displaying aggressive clinical behavior, resembling a mixed radiopaque and radiolucent radiographic appearance and containing both ameloblastoma and a composite odontoma. Seven-year-old boy complaining of delayed eruption of the left lower permanent 1st molar came to the department of Oral & Maxillofacial Radiology at Chonbuk National University Hospital. The list of our radiographic differential diagnosis included the dental follicle, compound odontoma, complex odontoma and cystic odontoma. The microscopic analysis showed the lesion with the characteristics of an ameloblastic odontoma. The obtained results were as follows; 1. The area was asymptomatic, but the delayed eruption of the left lower permanent 1st molar was observed. Radiographically, well-defined widened pericoronal radiolucency containing several tooth-like radiopacities involving the impacted left lower permanent 1st molar and well-defined round radiolucency containing irregular radiopaque mass were observed. 3. Histopathologically, several tooth-like structures, odontoma components with the area of typical enamel, dentin and pulp, and ameloblastic components with typical follicular ameloblastoma were observed.

• Journal of the korean academy of Pediatric Dentistry
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• v.21 no.2
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• pp.555-560
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• 1994

Among the permanent teeth. the first permanent molars play the greatest role in occlusion and function. So, the congenital missing, abnormal reuption or abnormal formation of the first permanent molars in the course of arch development would inflict normal development of dental arches. Therefore, early detection of abnormal cases related to first permanent molars and understanding of current and predictable clinical problems are essential for proper occlusal guidance in children. With the aim of investigating the clinical patterns of delayed eruption of first permanent molars in children, panoramic tomograms of the childern in mixed and early permanent dentition were observed and analyzed. The results were as follows: 1. Among the delayed eruption of first permanent molars, on tooth or bilateral teeths were affected most frequently. Delayed eruption was more prevalent in maxilla than in mandible. 2. The formation of tardily erupted teeth were also delayed. 3. Delayed eruption was generally limited in first molars or molar segments. 4. Delayed eruption of first permanent molars is accompanied by abnormal position of tooth germs, for example, ectopic eruption, delayed dental age, delayed localized tooth formation and generalized congenital missing. 5. There was a tendency of delayed formation or congenital missing of second molars distal to tardily erupted 1st molars. And that was more marked in maxilla than in mandible. 6. There was reported that affected 1st molars show various size and shapes. Maxillary 1st molars showing delayed eruption showed a tendency of having 3 cusps. But, tardily erupted mandibular 1st molars showed no significant reduction in mesiodistal dimension, as reported. 7. In some cases, the delayed eruption of 1st permanent molars was associated with ectopic eruption, but their formation was not usually retarded. 8. In skeletal class III cases, there showed a tendency of mandibular 1st molars to erupt earlier than maxillary 1st molars with greater interval than in normal occlusion.