• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.4
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• pp.625-630
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• 2009

Root resorption of primary teeth usually occurs as the succeeding permanent teeth erupt, which induces differentiation of the hemopoietic cells into osteoclasts. Their root resorption pattern reflects the eruption path of the succeeding permanent teeth, and eventually the primary teeth shed as their succeeding permanent teeth erupt. Even when a permanent tooth germ is congenitally missing, root resorption of the corresponding primary tooth may still occur due to various factors, such as inflammation, traumatic occlusal force, and weakness of periodontium etc. Such congenital missing of permanent teeth is a commonly observed phenomenon in human be ing, and it often accompanies delayed retention of primary teeth. The etiologic factors for congenital missing in elude not only systemic diseases, but also local factors and human evolution process. In the radiographs of the cases in this report, the primary teeth without succeeding permanent teeth show pathologic root resorption. Root resorption progressed about 1/2~3/4 of the roots, and the surfaces of the resorption area were irregular. Considering high susceptibility of the periodontal ligament of primary teeth to root resorption, pathologic root resorption of primary teeth with delayed retention can be explained by the increased masticatory muscle force and abnormal occlusion developed during the mixed dentition. When the primary teeth without succeeding permanent teeth are lost, decision for space maintenance is required and long-term treatment plan for further prosthetic or orthodontic treatment should be establsihed.

• 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.33 no.4
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• pp.722-727
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• 2006

Most of impacted teeth reported are permanent teeth. Impaction of primary tooth caused by primary failure of eruption is rare and the most of impacted primary tooth are second primary molars. The etiology of a primary molar impaction would appear to be a physical barrier, early ankylosis of the tooth, abnormal development of the primary molar germ or malposition of the successor bud. Transposition has been described as an interchange in the position of two teeth within the same quadrant of the dental arch. It is most commonly seen with canine and lateral incisor teeth, but is rarely associated with the primary dentition. The two cases show the transposition of impacted primary molar and the tooth germ of second premolar in their clinical and radiographic examinations. In case 1, lower second primary molar was deeply impacted inferiorly to the tooth germ suspected to be a second premolar. In case 2, impacted all second primary molars were positioned inferiorly to the tooth germs suspected to be the successors. We extracted all second primary molars under general anesthesia and the extracted tooth germs appeared to be second premolars.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.2
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• pp.309-314
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• 2007

Ameloblastic fibroma is a rare benign tumor, accounting for only 2.5% of odontogenic tumors. It occurs during the period of tooth formation between the ages of 5 and 20 years with the average age being about 15. There is no gender predilection. In the majority of cases, the lesion arises in the mandible, presenting the swelling of jaw and the failure of tooth eruption. In this report, the main concern of the patient was the failure of eruption of lower permanent and deciduous molars. Radiographic investigation showed a radiolucency surrounding the crown of unerupted teeth. Surgical intervention and histopathologic study revealed the lesion to be ameloblastic fibroma. After the surgery, no evidence of residual tumor or recurrency was found. These patients are scheduled for the long-term continuing evaluation of the eruption of adjacent teeth and successor with radiographic study.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.3
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• pp.481-488
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• 2009

Buckley's formocresol was first introduced as a pulp medicament in 1904, and since 1930, it has been the treatment of choice for primary molar pulpotomies. Formocresol has fixation effect of pulp tissue and high clinical success rate. But side effect such as displacement and loss of permanent successor, amelogenesis imperfecta, cyst formation, mutation by general absorption, possibility of cancer induction have been reported. Of those, dentigerous cyst can form in the periradicular region after formocresol pulpotomy caused by an alteration of the reduced enamel epithelium, which result in fluid accumulation between the epithelium and the tooth crown. The present case describes a 6-year-old girl who had accidentally discovered in the panoramic radiograph a single, well-defined, radioluscent area enclosing the second unerupted mandibular premolar. The second left primary molar had been pulpotomizied 3 year before. Surgical treatment was carried out, the primary molar was extracted and cystectomy was performed under local anesthesia. In the extracted second primary molar, formocresol cotton pellet was left in the pulp chamber. Histologic study confirmed the suspected diagnosis of dentigerous cyst. This report present a case of dentigerous cyst associated with inadequate formocresol pulpotomized deciduous molar.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.4
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• pp.368-376
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• 2020

The primary maxillary second molars usually have three roots. However, an additional root located mesiopalatally is occasionally observed. This study aimed to determine the relationship between a mesiopalatal root of primary maxillary second molars and an abnormal eruption pattern of maxillary second premolars. The study was performed on cone beam computed tomography images taken from 916 children who visited the Dental Hospital of Kyung Hee University from 2010 to 2018. 744 serial cross-sectional cone beam computed tomography images were evaluated. The overall incidence of the mesiopalatal root of primary maxillary second molars was 3.2% (n = 24) and the abnormal eruption pattern of maxillary second premolars was 19.2% (n = 143). Especially, patients with the mesiopalatal root of primary maxillary second molars were significantly more likely to have the abnormal eruption pattern on maxillary second premolars (p = 0.000). The odds of the abnormal eruption pattern of maxillary second premolars with the mesiopalatal root of primary maxillary second molars was about 13 times higher than those without. The eruption pattern of the permanent successor should be carefully observed and treated if the mesiopalatal root of primary maxillary second molar is existent.