• Journal of the korean academy of Pediatric Dentistry
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• v.45 no.4
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• pp.484-491
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• 2018

Tooth agenesis is a common human dental anomaly and the agenesis of mandibular second premolars has been proven to be the most frequently observed. The aim of this study is to investigate tooth agenesis and delayed tooth development in patients with agenesis of mandibular second premolars. This study reviewed 9 to 15 year-old patients with agenesis of mandibular second premolars who visited the department of pediatric dentistry of Yonsei University Dental Hospital and took panoramic radiographs from January 2014 to December 2016. On panoramic radiographs, agenesis of teeth was observed and developmental delay of teeth was evaluated by the Nolla method. Among 125 patients with agenesis of mandibular second premolars, 58 patients (46.4%) showed agenesis of other teeth and 38 patients (30.4%) showed delayed tooth development. In this study, patients with agenesis of mandibular second premolars were more likely to have tooth agenesis or delayed eruption of other teeth.

• The korean journal of orthodontics
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• v.51 no.5
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• pp.355-362
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• 2021

Objective: This study aimed to establish the prevalence and patterns of nonsyndromic tooth agenesis in patients referred to a tertiary health care facility. Methods: The intraoral records and panoramic radiographs of 9,874 patients aged 12-22 years were evaluated. The study group included 716 patients (371 male, 345 female) with non-syndromic agenesis of at least one tooth (except the third molars). The study data were assessed using descriptive statistics, chi-square test, and Mann-Whitney U test, while patterns were evaluated using a tooth agenesis code (TAC) tool. Results: A total of 1,627 congenitally missing teeth, were found in patients with non-syndromic tooth agenesis, with an average of 2.27 missing teeth per patient. The prevalence of tooth agenesis was 7.25%, and the most commonly missing teeth were the left mandibular second premolars (10.17%). The age group comparison revealed no significant difference in the median number of missing teeth per patient according to the cutoff values for ages between 12 and 22 years. When the missing teeth were examined separately according to quadrants, 114 different tooth agenesis patterns (upper right quadrant = 28, upper left quadrant = 27, lower left quadrant = 31, and lower right quadrant = 28) were identified, and 81 of these patterns appeared only once. Conclusions: This study highlights the benefits of applying the TAC tool in a large sample population. The application of the TAC tool in such studies will enable the development of template treatment plans by determining homogenous patterns of tooth agenesis in certain populations.

• Korean Journal of Cleft Lip And Palate
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• v.10 no.2
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• pp.81-88
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• 2007

Cleft lip and palate (CLP) is one of the most prevalent congenital craniofacial anomalies. It has a significantly greater incidence of dental abnormalities in number, size, shape, and eruption of the teeth. Knout-out mouse model can identify several genes which play an important role in tooth agenesis. Since disruption of these genes has been confirmed to result in tooth agenesis in humans, CLP associated with hypodontia may be the best models for isolated tooth agenesis. According to the studies of dental abnormalities in CLP, the severity of dental defect is known to be influenced by the CLP phenotype. The cumulative data obtained from mouse and human genetic studies indicated that MSX1, PAX9 and AXIN2 are considered as candidate genes in non-syndromic hypodontia, while Shh, Pitx2, Irf6, p63 and EDA pathway genes are involved in syndromic one. We expect that genetic approach of CLP can offer the basis for tooth regeneration and be a new target in hypodontia therapy.

• The Journal of Advanced Prosthodontics
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• v.8 no.3
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• pp.241-250
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• 2016

Oligodontia is defined as a congenital tooth agenesis with the absence of six or more permanent teeth. This clinical report describes a patient with non-syndromic partial oligodontia, with retained deciduous teeth and the absence of 16 permanent teeth. Anterior esthetic problems were caused by interarch tooth size discrepancy, interdental space, aberrant tooth dimensions, and the absence of centric contacts of the anterior teeth. Prosthetic restoration after orthodontic and implant treatment was performed with a multi-disciplinary team approach. Favorable functional and esthetic results were obtained using a definitive prosthesis.

• Journal of the korean academy of Pediatric Dentistry
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• v.51 no.1
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• pp.11-21
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• 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
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• v.51 no.1
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• pp.66-79
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• 2024

This study aimed to assess the prevalence and distribution pattern of dental anomalies in the permanent teeth of patients with non-syndromic cleft lip with or without cleft palate. Additionally, it aimed to compare differences in dental anomalies between cleft and non-cleft areas, considering gender and cleft phenotype. Panoramic radiographs of 164 patients diagnosed with non-syndromic orofacial clefts were retrospectively analyzed by a single examiner to confirm dental anomalies. The dental anomalies investigated included tooth agenesis, supernumerary teeth, microdontia, rotation, ectopic eruption, and enamel hypoplasia. Cleft phenotypes were categorized into 7 types based on medical and dental records. A significantly higher prevalence of supernumerary teeth was observed in males than females within non-cleft areas (p = 0.017), with no significant differences in other dental anomalies. In non-cleft area, patients with cleft palate exhibited a high prevalence of tooth agenesis (p < 0.0001) and microdontia (p = 0.012) compared to other cleft phenotypes. Maxillary incisor rotation was closely associated with adjacent tooth agenesis in unilateral cleft lip and palate cases (p = 0.034). This study suggests that the additional subphenotype based on dental anomalies in patients with orofacial cleft may serve as applicable clinical markers.

• The korean journal of orthodontics
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• v.52 no.5
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• pp.324-333
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• 2022

Objective: The aim of this study was 1) to investigate the prevalence and pattern of dental anomalies (DAs), 2) to compare DAs according to the type of malocclusion, and 3) to investigate the correlation between tooth impaction and other DAs in the Korean orthodontic population. Methods: A total of 3,240 orthodontic patients were classified as Class I, Class II, or Class III malocclusion groups. The presence and location of common DAs, including impaction, microdontia, agenesis, supernumerary tooth, transposition, and fusion, were identified by examining diagnostic records. Furthermore, samples were classified as Group 1 without impaction or Group 2 with impaction. The prevalence of other DAs concurrent with impaction was investigated and compared to Group 1. Results: Impaction was the most prevalent DA, followed by microdontia, agenesis, and supernumerary. Class I and Class III groups showed the same order of prevalence, but agenesis was more frequent than microdontia in the Class II group. The prevalence of the four DAs was lowest in the Class III group. Overall, 8.6% of patients were classified into Group 2. The incidence of DAs other than impaction and the prevalence of multiple concurrent DAs were significantly higher in Group 2. Impaction showed a significant relationship with supernumerary tooth, transposition, and fusion. Conclusions: The prevalence and pattern of DAs varied depending on the type of malocclusion. As there was a higher risk of other DAs in patients with impacted teeth, early detection of the impacted tooth and a detailed diagnosis of other possible DAs may be essential.

• Journal of the korean academy of Pediatric Dentistry
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• v.50 no.2
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• pp.179-191
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• 2023

The purpose of this study was to investigate the prevalence and patterns of congenitally missing teeth in permanent teeth excluding third molars, in patients aged 8 to 16 years who visited Pusan National University Dental Hospital from January 2010 to February 2021. This retrospective study evaluated tooth agenesis and the pattern of missing teeth represented by the tooth agenesis code by reviewing panoramic radiographs and electronic medical records of 11,759 patients, including 5,548 females and 6,211 males. The prevalence of congenitally missing teeth was 10.74% (females 11.95%, males 9.66%, p < 0.0001). Patients with tooth agenesis had an average of 2.22 missing teeth, and congenitally missing teeth occurred more frequently in the mandible (8.39%) than in the maxilla (4.52%, p < 0.0001). The mandibular second premolar (58.19%) was the most frequently missing tooth. The second premolar was the most frequently missing tooth in all quadrants (30.10%, 31.67%, 43.14%, and 35.59%) when a single tooth was absent, while the first and second premolars were the most commonly absent teeth (11.69%, 11.47%, 5.94%, and 5.24%) when two or more teeth were missing. In the relationship between maxillary-mandibular antagonistic quadrants and full mouth, the 1st to 4th place of the missing patterns were all involved with the 1st and 2nd premolars. This study can be clinically helpful in establishing a treatment plan for patients with missing teeth. In addition, it can be used as basic data for molecular biological research to find out the relationship between tooth agenesis and specific genes.

• Journal of the korean academy of Pediatric Dentistry
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• v.50 no.4
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• pp.421-433
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• 2023

This study was to examine the developmental dental abnormalities in childhood cancer survivors. Risk factors were assessed for 125 children with radiographic data through a retrospective analysis of medical records and panoramic images. 68.0% of childhood cancer survivors exhibited at least one dental abnormality. The types of abnormalities varied depending on the age at cancer diagnosis and treatment intensity, ranging from microdontia (43.2%), to abnormal root development (39.2%) and tooth agenesis (33.6%). Logistic regression analysis demonstrated that a young age at diagnosis (under 3 years), the use of heavy metal agents, a history of hematopoietic stem cell transplantation (HSCT), and combination treatment of chemotherapy, radiation therapy, and HSCT were associated with a significantly higher risk for overall dental abnormalities. The increased risk ratios were 6.00, 3.06, 3.22, and 7.87, respectively (p < 0.05). The results of this study will predict dental abnormality in permanent dentition according to the diagnosis age and treatment method of childhood cancer.

• The korean journal of orthodontics
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• v.47 no.5
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• pp.323-333
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• 2017

Orthodontic treatment of a complex case that involves retained deciduous mandibular second molars with missing permanent successors is challenging. Usually, congenitally missing teeth are manifested with other dental anomalies that further complicate orthodontic treatment, such as retained deciduous teeth, impactions, transpositions and peg-shaped lateral incisors. Even though the long term prognosis of the retained deciduous tooth is not fully predictable, if the teeth are in good condition, the patient and clinician may incline towards a decision to preserve the deciduous teeth as long as possible. This case report demonstrates that deciduous teeth, in this case the mandibular second molars and maxillary canine, can be incorporated into final occlusion with clinically stable long-term results.