• 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 korean journal of orthodontics
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• v.53 no.3
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• pp.150-162
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• 2023

Objective: To investigate craniofacial differences in individuals with hypodontia and explore the relationship between craniofacial features and the number of congenitally missing teeth. Methods: A cross-sectional study was conducted among 261 Chinese patients (males, 124; females, 137; age, 7-24 years), divided into four groups (without hypodontia: no teeth missing, mild: one or two missing teeth, moderate: three to five missing teeth, severe: six or more missing teeth) according to the number of congenitally missing teeth. Differences in cephalometric measurements among the groups were analyzed. Further, multivariate linear regression and smooth curve fitting were performed to evaluate the relationship between the number of congenitally missing teeth and the cephalometric measurements. Results: In patients with hypodontia, SNA, NA-AP, FH-NA, ANB, Wits, ANS-Me/N-Me, GoGn-SN, UL-EP, and LL-EP significantly decreased, while Pog-NB, AB-NP, N-ANS, and S-Go/N-Me significantly increased. In multivariate linear regression analysis, SNB, Pog-NB, and S-Go/N-Me were positively related to the number of congenitally missing teeth. In contrast, NA-AP, FH-NA, ANB, Wits, N-Me, ANS-Me, ANS-Me/N-Me, GoGn-SN, SGn-FH (Y-axis), UL-EP, and LL-EP were negatively related, with absolute values of regression coefficients ranging from 0.147 to 0.357. Further, NA-AP, Pog-NB, S-Go/N-Me, and GoGn-SN showed the same tendency in both sexes, whereas UL-EP and LL-EP were different. Conclusions: Compared with controls, patients with hypodontia tend toward a Class III skeletal relationship, reduced lower anterior face height, flatter mandibular plane, and more retrusive lips. The number of congenitally missing teeth had a greater effect on certain characteristics of craniofacial morphology in males than in females.

• The Journal of Advanced Prosthodontics
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• v.7 no.5
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• pp.406-410
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• 2015

Russell-Silver syndrome (RSS) is a congenital disease characterized by short stature due to growth hormone deficiency, physical asymmetry, inverted triangular face, micrognathia, prominent forehead, and hypodontia. This case report presents a prosthetic management of a 6-year-old patient with Russell-Silver syndrome treated with overdentures on the maxilla and the mandible using the remaining primary teeth. Subsequent and comprehensive dental management considering the growth and development of a young patient will be necessary.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.43 no.4
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• pp.267-271
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• 2017

Although it is a rare developmental malformation, van der Woude syndrome is the most common form of syndromic orofacial clefting, accounting for approximately 2% of all cleft cases. The lower lip pits with or without a cleft lip or palate is characteristic of the syndrome. Findings, such as hypodontia, limb deformities, popliteal webs, ankylogossia, ankyloblepheron, and genitourinary and cardiovascular abnormalities, are rarely associated with the syndrome. This paper reports a rare case of van der Woude syndrome in a 10-year-old male patient with a single median lower lip pit and a repaired bilateral cleft lip and cleft palate that were associated with microstomia, hypodontia, and clubbing of the left foot with syndactyly of the second to fifth lesser toes of the same foot.

• Korean Journal of Cleft Lip And Palate
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• v.4 no.2
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• pp.19-27
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• 2001

This study was performed to determine the prevalence of hypodontia and hyperdontia of permanent teeth among Korean schoolchildren, and to compare differences in the prevalence between Korea, other country, and other ethnic groups. The sample consisted of 346 girls aged 6.9～0.3 yr and 375 boys aged 6.8～0.4 yr on whom a panoramic radiograph was taken at Yeonchun-Gun community in Korea. The prevalence of congenitally missing teeth (third molars excluded) was 6.7% in boys and somewhat higher, 9.5% in girls, and 8.0% for both sexes combined. On the average, number of missing teeth per affected child was 1.9 teeth. The most commonly congenitally missing teeth were the mandibular second premolar (32.7%), followed by the mandibular incisor (28.7%), the maxillary second premolar (16.7%), and the maxillary lateral incisors (10.2%). The prevalence of supernumerary teeth was 2.1 % in boys, 1.4% in girls, and 1.8% for both sexes combined. The most common supernumerary teeth were the mesiodens (76.9%), followed by the supernumerary premolar (23.1 %). The affected male-female ratio was 1.6: 1.0. The prevalence of congenital missing teeth in this study was similar to in studies of Japanese, Danish, American and German. The frequency of hyperdontia was lower in this study than in studies of Chinese children, Japanese and American.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.1
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• pp.122-130
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• 2006

Congenital Missing Teeth(hypodontia, oligodontia) is the developmental absence of one or more teeth. It has been reported as being the most common anomaly of dental development in human, relatively common in the permanent dentition. In a recent review, Vastardis has quoted incidence ranges of $1.6%{\sim}9.6%$ in the permanent dentition. Brook has quoted a prevalence of $3.5%{\sim}6.5%$ in most populations, with severe hypodontia, defined as the absence of six or more teeth, having a prevalence of $0.3{\sim}0.4%$. The most commonly affected teeth are third molars, followed by maxillary lateral incisor, and second premolars. The etiology is unknown, several hypotheses include trauma, nutritional deficiency, infection, metabolic abnormalities, systemic disease and genetic influence. The multiple congenital missing is commonly associated with specific syndrome or severe systemic abnormalities such as cleft lip & palate and Down's syndrome. These cases present that children have multiple congenital missing teeth in the permanent dentition, without any systemic disease. Management of this condition must be considered orthodontic and prosthodontic treatment comprehensively. In these cases, children were treated by space maintainer or orthodontic appliance and follow-up checked.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.3
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• pp.532-542
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• 2007

The purpose of study was to review the transition of dentition according to the evolution of man to know the background of the dental problems like hypodontia and malocclusion. Man is Kingdom Animalia, Phylum Chordata, Class Mammalia, Order Primates, Suborder Haplorrhini, Superfamily Hominoidea, Family Hominidae, Genus Homo, Species Sapiens by taxonomy. The first hominid was Australopithecus which appeared c. 4 millions of years ago and showed bipedalism and distinct dentition. Homos began with H. habilis who appeared c. 2.5 millions of years ago and made stone tools, and then H. erectus and H. neanderthalensis appeared and disappeared until H. sapiens came. The dental formula of primitive mammalians which was I3 C1 P4 M3 changed to I2 C1 P4 M3 of primitive primates, to I2 C1 P3 M3 of Haplorrhini, and to I2 C1 P2 M3 of hominoids. That of H. sapiens is changing to I2 C1 P2 M2.The box type dentition of hominoids changed to the omega type dentition of Australopithecus, and to the parabolic type of H. sapiens. The size of teeth decreased continually, especially the canine and sexual dimorphism. The dentition moved backward and downward to the cranial crown according to the increase of the brain and decrease of the jaws. It was suggested that the change of diet to the starchy foods, food processing, and the development of cooking reduced the necessity of mastication and caused the change of dentition. The future of H. sapiens who is quite a new species in the earth histroy and is now causing the mass extinction of other species is hard to see. It seems that hypodontia and malocclusion are related to the dentition change according to the evolution of man and is likely to increase.

• Journal of the korean academy of Pediatric Dentistry
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• v.40 no.4
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• pp.274-282
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• 2013

The goal of this study was to analyze prevalence and distribution of congenitally missing teeth in 3302 patients from 7 to 15 years old, who had visited and taken panoramic radiographs at the Department of Pediatric Dentistry, from January 2008 to December 2012. The prevalence of hypodontia in the males (5.9%) was slightly higher than in the females (4.7%). In the affected patients, the mean number of congenitally missing teeth in the mandible was statistically higher than in the maxilla (p < 0.05). However, there was no significant difference in the number of congenitally missing teeth between left and right dentitions (p > 0.05). Excluding the Mn. third molars, the most frequent congenitally missing teeth site was the Mn. second premolars. In contrast, the most infrequent congenitally missing teeth sites were the Mx. and Mn. first premolars, and Mx. central incisors. The bilateral combination or antagonistic quadrants combination of congenitally missing teeth in hypodontia patients was 80.3%. The result of this study will contribute to clinicians to make accurate diagnosis and establish favorable treatment plans, by offering invaluable data about the number and distribution of congenitally missing teeth.

• Journal of the korean academy of Pediatric Dentistry
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• v.11 no.1
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• pp.255-259
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• 1984

Ectodermal dysplasia is a rare hereditary abnormality of which the outstanding characteristics are hypodontia, hypohidrosis and hypotricosis. Patient afflicted with this malformation shows a typical face resembling that of congenital-syphilis. Dental abnormality (delayed eruption, oligodontia) becomes apparent in this child and causes the parents to bring him to the dentist. Prosthetic appliances are usually indicated and he must be adjusted or be remade as the child matures.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.2
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• pp.222-228
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• 2000

Ectodermal dysplasia is a hereditary disease characterized by a congenital dysplasia of one or more ectodermal structures and their accessory appendages. At least 120 subtypes of ectodermal dysplasia have been reported. The disease is usually transmitted as an X-linked recessive trait in which the gene is carried by the female and manifested in the male. Hypohidrotic ectodermal dysplasia is manifested as a triad of defects that include hypohidrosis, hypotrichosis and hypodontia. The characteristic facial features consist of asteatosis, onchodysplasia, sparse and fine blond hair, prominent forehead, a depressed nasal bridge, thick everted lips. The patient may suffer from dry skin, hyperthermia and unexplained high fever as a result of the deficiency of sweat glands. This case report presents detailed procedures of rehabilitating functional and esthetic defect of a 6-year-old boy with hypohidrotic ectodermal dysplasia along with the review of relevant literatures.