• Journal of the korean academy of Pediatric Dentistry
• /
• v.51 no.1
• /
• pp.11-21
• /
• 2024

This study aimed to analyze the prevalence and severity of infraoccluded primary molars (IPM) and their correlation with the agenesis of permanent successors (APS). A total of 4,011 panoramic radiographs from children aged 4 to 11 years who had all 8 primary molars were examined. The prevalence of APS was analyzed based on the severity and tooth type of IPM. The prevalence of IPM was 13.0%, and there was no difference between genders. The majority of the children had two IPMs each. In all tooth types, mild infraocclusion was the most prevalent, whereas severe infraocclusion was the least frequent. Among the types of primary molars, the lower primary first molar (62.3%) was the most affected, followed by the lower primary second molar (27.7%), the upper primary second molar (5.8%), and the upper primary first molar (4.2%). Infraocclusion was 11.2 times more prevalent in the mandible than in the maxilla, with no significant difference between the left and right sides. The correlation between IPM and APS was also investigated. Among the subjects, 177 had one or more agenesis of premolars, of whom 54 (30.5%) had IPM. Additionally, among the 521 individuals with IPM, 54 individuals exhibited APS (10.4%). This study identified a noteworthy prevalence of infraocclusion, with notable variations among molar types. The LPFM was particularly affected. The majority of cases were classified as mild in severity. Furthermore, a compelling association between IPM and APS was established. Understanding this connection may enhance treatment strategies for infraoccluded teeth and tooth agenesis.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.4 no.1
• /
• pp.7-18
• /
• 1977

The author carried out to determine the normal range of eruptive time, average age and order of eruption of primary teeth in korean infants. The examimation was given to 1757 healty infants(Male 1032, female 725) from afterbirth 4 months to 32 months. The results was as fallows. 1. The eruption of primary teeth was 0.57 months earlier in male than in female. 2. The average month of eruption of primary teeth was as follows; Upper primary central is $9.66{\pm}0.19$ months Upper primary lateral is $11.58{\pm}0.18$ months. Upper primary canine is $18.06{\pm}0.32$ months. Upper first primary molar is $16.45{\pm}0.29$ months. Upper second primary molar is $24.28{\pm}0.51$ months. Lower primary central is $7.50{\pm}0.12$ months. Lower primary lateral is $12.87{\pm}0.16$ months. Lower primary camine is $18.82{\pm}0.34$ months. Lower first primary molar is $17.66{\pm}0.37$ months. Lower second primary molar is $23.89{\pm}0.51$ months. 3. The eruptive order of the korean is different from that of the American and same to that of Japanese. 4. There is no significant right and left arch. 5. Generally, the eruption of primary teeth on the upper is 1.08 months earlier than on the lower; but the upper central is 2.16 months later than the lower and the upper second primary is 0.39 months later than the lower.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.25 no.2
• /
• pp.383-399
• /
• 1998

Tooth development is usually described in four stages such as bud stage, cap stage, bell stage and crown stage. Exact time of appearance of tooth primordia is different among reports, and up to now there is no timetable regarding initial tooth development. To understand the congenital malformations and other disorders of the orofacial region, there is a need to establish a standard timetable on early tooth development. Till now, studies on the tooth development were mainly on later fetuses, and only few reports on early stage. Also, there were no reports on the time when bud stage turns to cap stage, and cap stage to bell stage. In this study, external morphology of face and the early development of the tooth, and transition of bud stage to cap stage, cap stage to bell stage were studied using 27 staged human embryos and 9 serially sectioned human fetuses. The results are as follows: 1. Mandibular region was formed by union of both mandibular arch at stage 15, and maxillary region by union of maxillary arch, medial nasal prominence, and intermaxillary segment at stage 19. 2. Ectodermal thickening which represents the primordia of tooth appeared in mandibular region at stage 13, and maxillary region at stage 15. 3. Bud stage began from mandibular primary central incisor at stage 17, and maxillary primary central incisor at stage 18. And the sequence of appearance was in the mandibular primary lateral incisor at stage 19, maxillary primary lateral incisor at stage 20, mandibular primary canine at stage 22, maxillary primary canine and primary first molar at stage 23, madibular primary first molar and maxillary primary second molar at 9th week, and mandibular primary second molar at 10th week of development. 4. Cap stage began from the primary anterior teeth at 9th week, and primary second molar still had the characteristics of cap stage at 12th week of development. 5. Transition to bell stage started from the primary anterior teeth at 12th week, and primary second molar started at 16th week of development. 6. Trnasition to crown stage started from primary anterior teeth at 16th week, and primary second molar at 26th week of development.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.49 no.3
• /
• pp.340-347
• /
• 2022

Distal displacement of the tooth germ of the mandibular second premolar (MnP2) leads to its impaction and obturation of the eruption path of the mandibular first molar delaying its eruption. The present case report describes the treatment of 2 cases of eruption guidance for distally displaced developing MnP2 that caused delayed eruption of the mandibular first molar. Intentional extraction of primary predecessor results in the mesial shift of the displaced MnP2. However, unfavorable distal ectopic eruption of the mandibular first premolar after the premature loss of primary second molar has been previously reported. Hemisection and sequential extraction of the mandibular primary second molar were performed to mesially shift the distally displaced MnP2, while preventing unfavorable distal ectopic eruption of the mandibular first premolar.

• The Journal of the Korean dental association
• /
• v.50 no.6
• /
• pp.322-328
• /
• 2012

Ectopic eruption of the permanent first molar is defined as the eruption of the tooth in an abnormal position or orientation. It may causes distal root resorption and premature exfoliation of the adjacent primary second molar and uncontrolled space loss is followed. Prolonged partial impaction of the permanent molar may also cause undetected caries or abscess formation of the neighbor teeth. The purpose of this paper is to provide a brief review regarding the etiology, classification, and different management techniques for correcting ectopic eruption of permanent first molar.

• The Journal of the Korean dental association
• /
• v.15 no.4
• /
• pp.309-311
• /
• 1977

Statistically inquiring into dental health index of permanent first molar for 1785 pupils of Y primary School in Seoul. I got a conclusion as follows: 1. Female was lower than male in dental health index and conversely in DMF rate. 2. Elder pupils were lower than younger pupils in dental health index and conversely in DMF rate.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.43 no.2
• /
• pp.187-191
• /
• 2016

Early loss of a primary second molar can cause mesial drift or tilting of the permanent first molar. We present a case of the early loss of the mandibular primary molars in a 5-year-old girl. The patient required extraction of the mandibular left primary first and second molars due to folliculitis on the successors. A flexible denture was used for eruption guidance of the permanent first molar and the recovery of masticatory function simultaneously.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.37 no.4
• /
• pp.519-525
• /
• 2010

Ectopic eruption means the eruption of the tooth in an abnormal position due to multiple factors, which found most frequently in maxillary fist permanent molars, mandibular lateral incisors and maxillary permanent canines. Ectopic eruption of the maxillary first permanent molar occurs when the molar erupts with a more mesial angulation than normal, and locks itself in an atypical resorption on the distobuccal root of the second primary molar. The maxillary first permanent molar plays important roles for mastication and occlusion, so ectopically erupted maxillary first permanent molars should be relocated into proper position. Treatment options are separation by insertion of the brass wire or elastic rings, preparation of distal aspect of the maxillary second primary molar, using fixed or removable appliance with finger spring, and placement of space maintainer or space regainer after extraction of the maxillary second primary molar. We report three cases treated of ectopically erupted maxillary first permanent molar by re-setting of stainless steel crowns, placement of brass wire and using active plate. We could find out distal movement of maxillary first permanent molars into proper position and normal occlusion.

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

• The Journal of Korea Assosiation for Disability and Oral Health
• /
• v.12 no.2
• /
• pp.45-49
• /
• 2016

This study investigates the success rate of pulpotomy using electrosurgery operated on a primary molar in caries. The pulpotomy using electrosurgery was done on 253 primary molars of 111 young patients from 2 to 9 years old during the period of the first day of January 2011 to the last day of December 2015. After the amputation of pulp and hemostasis of primary molar were done using electrosurgery, MTA as pulp capping material was applied to the primary molar and the tooth was restored with the stainless steel crown. The follow up period after the treatment ranged from 4-46 months. The clinical and radiographic success rate ranged from 92.1 - 94.3%. Which is comparable to formocresol and ferric sulfate pulpotomy. Due to its non-pharmacological characteristic, electrosurgery can minimize harmful effect on the pulp tissue. Its fast bleeding control makes it easy and safe to use in pediatric and disabled patients in comparatively simple manner. Electrosurgery can be an alternative for pulp therapy considering the side effects of pharmacological ways.