• Journal of Dental Rehabilitation and Applied Science
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• v.28 no.4
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• pp.407-421
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• 2012

Orthodontic problems of the oral maxillofacial area could be classified into skeletal and dental problems. Dental problems might cause various occlusal disharmony and among them congenital missing or eruption failure might cause not only functional problems but also esthetic problems. Additional psychological problems are also one of the reasons for patients seeking treatment. In cases showing eruption failure of many teeth in the maxilla, not only occlusal and esthetic problems but also difficulty in alveolar bone maintainment could occur. Therefore, successive approach is necessary when multiple teeth show eruption problems. In this case, a patient with eruption problems of #13, 12, 11, 23, 43 was successfully treated by surgical exposure and successive orthodontic extrusion resulting perfect occlusion. By additional periodontal treatment, gingival recession that occurred along with teeth eruption was solved. The impacted right mandibular canine was erupted successfully only by natural arch expansion and leeway space without any special surgical treatment.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.2
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• pp.253-261
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• 2009

The purpose of this study was to present new data on the timing and sequence of permanent teeth emergence and to compare these findings with the results of earlier studies. The dental examinations had been performed to E-elementary school students, who visited the Yonsei University Dental Hospital between 1998 and 2005; 1,307 boys and 1,312 girls with the age ranging from 6 to 12 years old. The followings were concluded. 1. Eruption time of the maxillary permanent teeth is as follows. It was 6.81 years in male and 6.73 years in female for the central incisor, 7.78 years in male and 7.65 years in female for the lateral incisor, 10.48 years in male and 9.92 years in female for the canine, 9.76 years in male and 9.63 years in female for the first premolar, 10.66 years in male and 10.49 years in female for the second premolar, 6.39 years in male and 6.26 years in female for the first permanent molar, and 12.13 years in male and 12.03 years in female for the second permanent molar. 2. Eruption time of the mandibular permanent teeth is as follows. The central incisor could not be determined in this study, but it is assumed to erupt before the age of 6.08. In the mandible, eruption time was 6.78 years in male and 6.65 years in female for the lateral incisor, 9.76 years in male and 9.05 years in female for the canine, 9.82 years in male and 9.59 years in female for the first premolar, 10.67 years in male and 10.52 years in female for the second premolar, 6.22 years in male and 6.12 years in female for the first permanent molar, and 11.58 years in male and 11.14 years in female for the second permanent molar. 3. The eruption sequence is as follows. In the maxilla, 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 mandible, the central incisor erupted first, followed by the first permanent molar, the lateral incisor, the canine, the first premolar, the second premolar, and the second permanent molar. 4. Tooth eruption occurred earlier in female compared to male by average of 0.19 year in the maxilla and 0.29 year in the mandible. 5. In both male and female, the hiatus (interval of rest) occurred between the emergence of lateral incisor and first premolar in the maxilla while it was observed between the lateral incisor and canine in the mandible. Male had a hiatus of 1.98 years in the maxilla and 2.90 years in the mandible, while the female's were 1.98 years and 2.40 years, respectively.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.4
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• pp.385-390
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• 2011

When many factors involved in the eruption of the teeth act as negative effects, they can cause eruption disturbance. Periodic observation, space acquirement, surgical exposure, orthodontic traction, orthodontic traction accompanied with surgical exposure, and surgical repositioning are considered as the treatment options of an impacted tooth, which is a form of eruption disturbance. In the first case, a male patient, age 9, visited Yonsei University Dental Hospital (YUDH) with a chief complaint of ectopic impaction of the upper left lateral incisor. We extracted the upper left primary lateral incisor and primary canine, and 5 months later, a window opening procedure was executed. Eight months later, the upper left lateral incisor partially erupted, and 18 months after the extraction, the axis of the tooth improved and the tooth erupted spontaneously. In the second case, a male patient, age 10, visited YUDH with a chief complaint of ectopic impaction of the upper right first premolar. We extracted the upper right first primary molar. Ten months later, the upper right first premolar erupted partially, and 19 months after the extraction, the upper right first premolar erupted spontaneously. We reported two cases in which improvement of eruption path and spontaneous eruption of an ectopic impacted tooth was achieved by extracting the deciduous tooth which interfered with the proper eruption of it.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.3
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• pp.317-327
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• 2010

Among the permanent teeth, the first permanent molars play the greatest role in occlusion and function. So, early diagnosis for congenital missing, abnormal eruption and abnormal formation is very important to the first permanent molars in the course of arch development. The aim of this study is to analyse the differences between right and left first permanent molar's formation and eruption and between upper and lower one. A total of 545 children were selected am ong children who had visited our clinic, investigate eruption and calcification stage of permanent first molar, based on Gleiser and Hunt criteria for this study. 1. Gingival emergence of mandibular first molar is faster than maxillary first molar by 0.75~0.8 years, gingival emergence of maxillary first molar in girls faster than boys by 0.45 years, and that of mandibular first molar in girls faster than boys by 0.5 years. 2. There is the significant difference between right and left first molar on the eruption score and the calcification stage ; 5 year old children show the significant difference on the eruption score. 7 year old children show the significant difference on both the eruption score and calcification stage. 3. It shows the most active eruption movement of crown on the maxilla while the root is rapidly widening its furcation and completing root formation to 2/3, on the other hand, the most active crown emerging on mandible is shown when the root formation completed to 1/4 to 1/2.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.1
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• pp.117-123
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• 2010

Tooth eruption is the movement of the tooth from the developing place in the alveolar bone to the functional position in the oral cavity. The permanent incisors originate from the dental lamina on the lingual side of preceding deciduous tooth and erupt to the level of the occlusion through the well developed gubernacular cord. Ectopic eruption is a developmental disturbance in the eruption pattern of the permanent dentition. Most of the ectopically erupted lower incisor has been found in lingual side. The ectopically erupted tooth could be repositioned by orthodontic force in the early mixed dentition, which could help preventing the problems of loss of space and the lingual tilting of the lower anterior teeth. An eight-year-old girl visited the department of pediatric dentistry, Yonsei Dental University Hospital, for the evaluation and the treatment of the lower right lateral incisor, which was horizontally erupted in the lingual side, parallel to the mouth floor. Her tongue was placed on the labial side of that tooth. There was no previous dental history of dental caries or trauma on the pre-occupied primary incisor. Clinical and radiographic examinations including the computed tomography(CT), showed no evidence of dilacerations on root. Therefore, we decided to start active orthodontic traction of the lower right lateral incisor. We designed the fixed type of buccal arch wire and the lip bumper with hook for the traction. Button was attached to the lingual side of the ectopically positioned tooth. Elastic was used between the appliance and the button on that tooth. After the tooth become upright over the tongue level, appliance was change to the removable type and periodic check-up with occlusal guidance was followed to monitor the position of the tooth. In this case using the fixed appliance with modified form of lip bumper and hook embedded in acrylic part instead of extraction was very efficient up-righting the ectopically erupted tooth toward the occlusal plane.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.3
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• pp.495-501
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• 2003

Impaction is defined as the cessation of the eruption of the tooth caused by a clinically or radiographically detectable physical barrier in the eruption path or by the ectopic position of tooth germ. Besides the third molars and the maxillary canines, the most common impacted tooth is the second premolar. The overall frequency of premolar impaction has been reported to be 0.5%. In some cases, orthodontic traction and surgical repositioning may be indicated. When impacted second premolar is involved with prolonged retained second primary molar, extraction of primary molar and space maintenance lead to eruption of second premolar. In these cases, all patients visited to department of pediatric dentistry of Kyungpook National University Hospital for the chief complaint of unerupted second premolar. Extraction of prolonged retained second primary molar and space management are tried for spontaneous eruption of impacted second premolar tooth. The results were as follows: 1. When impacted second premolar is involved with prolonged retained second primary molar, minimal treatment via elimination of primary molar leads to successful results. 2. Proper space management and periodic radiographic examination are required before eruption of second premolar. 3. Sufficient time must be allowed for confirm of tooth movement before orthodontic traction or surgical repositioning. 4. The result is more successful in incomplete root development.

• The korean journal of orthodontics
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• v.40 no.4
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• pp.267-275
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• 2010

Objective: The aim of this study was to evaluate and compare the shear bond strength (SBS) and failure-mode of orthodontic buttons bonded to erupted and unerupted teeth with conventional and self-etching adhesive systems. Methods: Eighty-four erupted and 84 unerupted, human third-molar teeth were used. For both groups, the buccal surfaces of each tooth were assigned one of the following type of adhesive systems (n = 12). A, Conventional systems: 1, Transbond XT (3M Unitek, Monrovia, CA, USA); 2, Prime & Bond NT (Dentsply/Caulk, Milford, USA); 3, Single Bond (3M ESPE, Minnesota, USA); and B, Self-etching adhesives; 4, Clearfil SE Bond (Kuraray, Okayama, Japan); 5, Transbond Plus (3M Unitek, Monrovia, CA, USA); 6, Clearfil S3 (Kuraray, Tokyo, Japan); 7, G Bond (GC, Tokyo, Japan). The SBSs of the attachments and the adhesive remnant index (ARI) scores were recorded. Data were analyzed with analysis of variance (ANOVA), independent-sample t-test and chi-square tests. Results: When the SBSs of erupted and unerupted teeth were compared, only the Clearfil-SE Bond and G-Bond were significantly different. Bond strengths of all adhesive systems were higher in unerupted teeth than erupted teeth, except the Single-Bond system. Conclusions: When using conventional adhesives, bonding to erupted and unerupted teeth may not be significantly different. However, clinicians need to take into consideration the types of self-etching systems before usage.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.3
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• pp.325-336
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• 2009

The purpose of this study was to investigate the eruption pattern of the mandibular first molar in sagittal, frontal and horizontal views using the cone beam CT scanning. CT images were obtained from healthy 83 children (42 boys, 41 girls) between 3 to 10 years of age with a normal dentition according to Nolla stage. 1. In the frontal and horizontal view, the intermolar width decreased continuously with stage and slightly increased at the last stage. 2. In the sagittal and frontal view, eruption distances from occlusal plane were observed the largest change between stage 5 and 7. 3. In the horizontal and sagittal view, mandibular first molar from distal surface of primary second molar moved distally between stage 4 and 6. 4. In the sagittal view, angle from occlusal plane to mesio-distal axis increased between stage 4 and 8. 5. In the frontal view, angle from occlusal plane to bucco-lingual axis increased continuously during all stage. 6. In the horizontal view, angle from midsagittal plane to long axis increased between stage 5 and 8.

• Journal of the korean academy of Pediatric Dentistry
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• v.40 no.4
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• pp.314-320
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• 2013

With a prevalence rate of 0.01%, the presence of eruption disturbances of mandibular first molar has rarely been in populations. Eruption disturbances of permanent molars have been usually manifested as impaction, primary retention, and secondary retention. The treatments of eruption disturbances are carried out by: periodic observation; surgical exposure; forced eruption after surgical exposure; forced eruption with luxation; surgical repositioning; and extraction. This case report show successfully erupted mandibular first molars by various treatment methods on five patients diagnosed with impaction, primary retention, and secondary retention, respectively. Eruption disturbances of the mandibular first molar can be properly diagnosed with impaction, primary retention, and secondary retention by clinical and radiographic examination at normal eruption time of the mandibular first molar. The treatment should be done synthetically, considering eruption state of affected tooth, the relationship between the affected tooth and the adjacent or opposite tooth, the patient's age, treatment compliance, and economic state.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.4
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• pp.665-670
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• 2004

The mandibular buccal frenum becomes a problem when its attachment is too close to the marginal gingival. Heavy buccal frenum mucogingivally results in insufficient attached gingiva, inadequate vestibular depth and also difficulty in eruption of mandibular premolar. The aim of this study is to demonstrate the effectiveness of apically positioned partial-thickness flap as adequate method in order to remove heavy buccal frenum and expose impacted teeth. The author presents the case of a 12-year-old boy. He had problems that was prolonged eruption of #34, #35 due to high pull buccal frenum. After space regaining for normal eruption of #34, #35, we performed apically positioned partial-thickness flap on #34, 35 area. As a results, we confirmed that eruption of #34, #35 has been processed normally And vestibular depth, position of buccal frenum and width of attached gingival was within a normal range. Decrease in muscle pull, adequate width of attached gingiva and increased vestibular depth can be expected from this treatment.