• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.2
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• pp.219-227
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• 2020

Tooth eruption involves a complex developmental process of tooth migration from the dental follicular origin to the final occlusion position in the oral cavity via the alveolar process. Disturbance of tooth eruption can occur at any point in a series of eruption stages; however, horizontal impaction of the mandibular first molar and primary retention of the primary mandibular second molar are rarely observed simultaneously. This study describes the treatment for two cases of horizontally impacted first molar with primary retention of primary molar. The primary retention of the primary mandibular second molar was extracted, and orthodontic traction was applied to the horizontally impacted primary mandibular first molar. Subsequently, displacement of the premolar tooth bud was improved and space regaining for eruption was achieved, guiding to normal eruption of the first molar.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.1
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• pp.89-100
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• 2005

The purpose of this study was to analyze the morphometrics of primary second molar and permanent first molar. Samples were consisted of normal occlusion in the primary dentition(50 males and 50 females) and permanent dentition(43 males and 43 females). Their upper and lower plaster casts were used and their measuring points were decided, through 3-dimensional laser scanning(3D Scanner, DS4060, LDI, U.S.A.), fitting standard horizontal plane were made for measuring the intercuspal distance, volume of intercuspal area and section curve. The results were as follows; 1. Average distance from the fit plane to the cusp tips of mandibular primary second molar was smaller than any other tooth. (0.05-0.09 mm in male and 0.04-0.09 mm in female). 2. Intercuspal distances of mandibular primary second molar and permanent first molar were larger in male than in female. Especially, there was statistical significance in primary second molar(p<0.05). 3. Intercuspal distance between distobuccal and distolingual cusp was larger in maxillary primary second molar, except cross intercuspal distances. And distances between distal and distolingual cusp, in mandibular primary second molar, between mesiolingual and mesiobuccal cusp, in maxillary first molar, and between distolingual and mesiolingual cusp, in mandibular first molar were larger than any other intercuspal distance. 4. Volume of intercuspal area of primary second molar and permanent first molar was larger in mandible than in maxilla and that of permanent first molar was 1.40-1.75 times of primary second molar (p<0.05). Also it was larger in male than in female, but there was no statistical significance. 5. In most cases, section curves were wider and deeper in permanent dentition than in primary dentition. Except cross intercuspal distances, in maxilla, section curve between mesiobuccal and mesiolingual cusp was the deepest in both dentition. In mandible, section curve between distobuccal and distal cusp was the deepest in permanent dentition and between distolingual and distal cusp was the deepest in primary dentition.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.2
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• pp.151-158
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• 2010

The purpose of this study was to investigate the tooth surface caries patterns in the primary dentition according to breast or bottle feeding. The subjects of study were 815 children, 36 to 71 months old, in Iksan, Cheongju and Ulsan cities. The caregivers of the children were asked which they fed between the breast milk and the infant formula during the 1st year after birth and the duration of feeding. There was no significant difference in dmfs between the breast milk group and the infant formula group(significance level 0.05, same below). Tooth groups, tooth surface groups, teeth, and tooth surfaces which had significantly higher dmfs in the breast milk group than in the infant formula group were upper anterior teeth(tooth groups), upper incisors' buccal and proximal surfaces(tooth surface groups), upper incisors and upper second molars(teeth), upper central incisors' buccal and distal surfaces, upper lateral incisors' buccolingual and proximal surfaces, upper 2nd molars'lingual, proximal, and occlusal surfaces, and lower 2nd molars' buccal and distal surfaces. In the breast milk group, tooth groups, tooth surface groups, teeth, and tooth surfaces which dmfs significantly increased as the duration of the feeding increased were upper anterior teeth and upper molars(tooth groups), upper anterior teeth's proximal surfaces, upper molars' buccolingual, proximal, and occlusal surfaces, lower molars' proximal surfaces(tooth surface groups), upper anterior teeth, upper molars, lower 2nd molars(teeth), upper anterior teeth's proximal surfaces, upper 1st molars'buccolingual, proximal, and occlusal surfaces, upper 2nd molars' buccal surfaces, and lower 2nd molars'mesial surfaces(tooth surfaces). In the infant formula group, dmfs increased after 3 years of feeding, but the difference was not significant. Caries prevention is necessary in case of breastfeeding more than two years.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.4
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• pp.643-652
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• 2006

The purpose of this study was to elucidate the size and morphologic characteristics of maxillary primary first molars in Korean children using three-dimensional laser scanner and compare three-dimensional image with preformed stainless steel crown. Scanned three-dimensional images of dental cast taken from 132 children(male 62, female 70) by three-dimensional laser scanner(Breuckmann opto-Top HE100, INUS, Korea) were used. Mesiodistal diameter, buccolingual diameter, occlusogingival height and crown shape of each image were calculated by Rapidform 2004 program(INUS, Korea). The values were statistically compared by independent samples t-test with 95% of significant level. The results were as follows : 1. No significant difference in crown size was found between left and right maxillay primary first molar(p>0.05). 2, Significant difference in mesiodistal diameter, buccolingual diameter, buccal occlusogingival height was found between male and female (p<0.05), and crown size of male was bigger than that of female. 3. Average image of maxillay primary first molar was shaped three-dimensionally and measured. In comparison with 3M stainless steel crown, this image was similar with No.4 or No.5 SS crown in male, No.4 in female. In comparison with ILSUNG SS crown, this image was similar with No.5 in male, No.4 in female. 4 Mesiolingual line angle area, distolingual line angle area and buccogingival ridge were more obvious in average image than 3M stainless steel crown. ILSUNG SS crown was more square and had longer mesiodistal diameter than average 3D image.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.3
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• pp.403-408
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• 2005

Ankylosis is defined as a fusion of cementum or dentine with alveolar bone. Due to the loss of the periodontal ligament on the ankylotic area, the tooth is incapable of continued eruption and hence is unable to follow the normal vertical development of the neighboring teeth and alveolar process. A 6-year-old female was referred to the Dept. of Pediatric Dentistry for ankylosis of primary molars and congenital missing of permanent premolars on both jaws. She had neither specific past medical history nor trauma and infection history in oral and maxillofacial region. Radiographic finding is that the maxillary primary molars were the early onset of ankylosis and had fast root resorption rate. However the mandibular primary molars were ankylosed later and being resorbed slower than maxillary primary molars. The object of treating this case is to maintain the proper alveolar bone growth and retention of deciduous molars. The point of managing this case is as follows: Proper treatment (observation, restoration, or extraction) should be established after thorough consideration of the time of onset, the root resorption rate, progression of infraocclusion and the development of alveolar bone support. We should consider the timing of extraction of the ankylosed teeth without problem of neighbouring alveolar bone growth and tilting of adjacent teeth in the view of growth spurt. Early diagnosis is important to avoid many of the complications with infraoccluded primary molars.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.2
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• pp.153-158
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• 2004

Preformed stainless steel crown is an useful restorative material for the treatment of badly broken down primary teeth. However iatrogenic damage to adjacent teeth might occur during the process of tooth reduction. Such damages might lead to plaque accumulation and increase the risks of caries initiation. Especially the damage can make a problem in the first permanent molar. Purpose of this study was to investigate an iatrogenic damage to the first permanent molar during preparation of second primary molar for preformed stainless steel crown. Twelve children restored with preformed stainless steel crown to second primary molar were selected. Contact areas were separated with separation elastics, and tooth surfaces were cleaned. After taking negative impression using vinylpolysiloxane impression material, the specimens were examined by scanning electron microscope for the detection of iatrogenic damage. The prevalence of iatrogenic damage was 66.7% and variable appearances and So we can suggest that when preparing teeth for preformed stainless steel crown, we should be careful about adjacent teeth not to make an iatrogenic damage.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.4
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• pp.337-347
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• 2011

The basic structure of the primary crowns usually resemble their succeeding permanent teeth. However, maxillary second primary molars resemble ipsilateral first permanent molars. Accordingly in this study, odontometric data of the two teeth was obtained, then analyzed to verify the morphological relationship and sex difference between the two teeth. Dental study casts were examined for their mesiodistal and buccolingual width of the crowns, diameter of each cusps, and intercuspal distances. Photographs of the crowns were taken to measure the angles between each cusp tip. The results are as follows : 1. In boys, PrI, PaI, DBC angle, and MBC angle did not show any statistically significant difference between the two teeth(p>0.05), and moderate level of correlations were observed. 2. In girls, crown index, DBC angle, and MBC angle of the two teeth did not show any statistically significant difference(p>0.05), and moderate level of correlations were recognized. 3. Measurements that did not show statistically significant difference between the two teeth in both boys and girls were DBC angle and MBC angle(p>0.05). In DLC angle, however, statistically significant difference was observed(p<0.01). 4. Most of the measurements showed sex differences, except DBC angle, which did not show any sex difference in both teeth(p>0.05).

• Journal of the korean academy of Pediatric Dentistry
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• v.44 no.1
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• pp.99-107
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• 2017

In the management of ankylosed primary molars, early diagnosis, proper treatment, and thorough follow-ups are very important. Untreated infraocclusion due to ankylosis has a negative impact on normal occlusal development, and may cause problems. There are many treatment options on infraoccluded deciduous molars, such as periodic observation, conservative method, restoration, and space regaining via extraction of the teeth. In this case report, two 6-year-old girls were diagnosed with ankylosed maxillary second primary molar and displaced tooth germ of the second premolar. Early surgical removal of the ankylosed primary molar was considered as a treatment approach. The long-term follow-up shows normal eruption of a succeeded permanent premolar.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.3
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• pp.352-358
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• 2021

Molar-incisor malformation (MIM) is characterized by malformation in the root with a normal crown. While MIM mostly occurs in the permanent first molar, it has also been reported in the maxillary central incisor and the primary second molar (PSM), but anatomical analysis of the primary teeth with MIM has not been studied to date. In this case report, a patient with MIM was reported, and an extracted PSM with MIM was analyzed with micro computed tomography (CT). A cervical constriction morphology of the cementoenamel junction (CEJ) can be observed in extracted PSM. In micro CT analysis, characteristics such a mineralized plate (cervical mineralized diaphragm) in the CEJ area, complex root canal morphologies, a calcified mass inside the pulp chamber, and constricted pulp chamber of crown portion were observed.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.4
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• pp.391-398
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• 2011

The infraocclusion usually occurs in the mixed-dentition stage, and it is commonly accepted that the cause of the infraocclusion is ankylosis. The treatment options for patient with infraocclusion of primary molars are observation, restoration or surgical removal of the affected teeth. If the successors are present, most of the infraoccluded and ankylosed primary molars may occur normally. However, when the permanent successors are absent and the progression of infraocclusion is found, affected teeth may need to be extracted. In the case of infraocclusion which can cause vertical alveolar defect due to ankylosis, extraction before growth spurt should be performed for the future prosthetic treatment. A six-year-old female had the ankylosis and infraocclusion of multiple primary molars and congenital missing of premolars. The affected primary molars were extracted before growth spurt to avoid a significant vertical ridge defect and to promote the vertical development of alveolar bone, and the result was observed for many years. The purpose of this report is to report the management of multiple infraoccluded primary molars without permanent successors in a young patient.