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183
SL-069
Hypodontia in Mosaic and Full Down Syndrome Patients
W i l l y a n t i W i l l y P e d i a t r i c D e n t i s t r y
Faculty of Dentistry Padjadjaran University
Abstract
Background: Hypodontia is the congenital absence of the teeth with one or more teeth
missing. There are major conditions/syndrome that manifest as hypodontia such as Down syndrome. Mosaic and full caryotype in Down syndrome patients have different prognostic appearance. Objective: The aim of this study was to find the occurrences of hypodontia in mosaic and full Down syndrome patients. Methods: In this cross sectionalstudy, a number of
26 Down syndrome patients were included, comprising of 18 fulland 8 mosaic types. Mosaic and full Down syndrome were determined by clinical manifestations, chromosomal analysis, and kariotyping. While hypodontia was determined when one or more teeth are missing in each jaw, aw, and by radiographic examinations when no follicle was present/detected. Results:
The results showed that hypodontia occur in 1 of 8 mosaic patients, and 7 of 18 full patients. We found out that hypodontia occur significantly more often infullDown syndrome patients (p =0. 002). Conclusion: It is concluded that hypodontia occur in both mosaic and full Down
syndrome patients, but more often in full Down syndrome patients. The lateral incisor is the most often affected tooth.
Key words: mosaic,fulltype down syndrome, hypodontia
Introduction
Hypodontia is the developmental absence of one or more primary or permanent teeth,
and characterized by congenital absence of some teeth from the dental arch that denotes the lack
of development of one or more teeth. Oligodontia indicates the absenoo of oinor teeth
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Hypodontia is defined as reduction of the teeth number, where one or more teeth are
missing and no follicle are present. This condition is classified as syndromic and non
syndromic hypodontia.6
In normal patients, hypodontia in primary dentition is more common in the maxilla
and affects the lateral incisor, but in permanent dentition, hypodontia occurs with equal
frequency in the upper and lower jaw and commonly affects the third molar. The incidence of
hypodontia is 0.1-0.9% in the primary dentition, 3.5-6.5% in permanent dentition, and the
gender ratio is not known.7 Some degrees of hypodontia are not uncommon, occurring
sporadically or with a hereditary factor. The etiology of hypodontia are genetic and
environment tactors, and the genetic control appears to exert influence on the teeth
development.
In addition, many non-syndromic numeric alterations of teeth show a strong genetic
correlation. More than 30 syndromes are associated with hypodontia, and Down syndrome is
the most common, in which there might be an increased on the prevalence of hypodontia.3,6,8
Down syndrome is a syndrome caused by an existence of extra chromosome at
chromosome 21. Down syndrome (DS) or trisomy 21 is the most common chromosomal
aberration with variable clinical manifestations.9,10,11
The incidence of Down syndrome is high enough, about 1 in 800 of live births from
mothers aged below 30 years and increase to become 1 in 65 births from mothers above 45
years old. The incidence of DS has tended to increase as the mother's age increase.1,2, 8
Normal human being has 46 chromosome or 23 chromosome tide, consisting of 22
tides of autosom and a pair of sex chromosome in every cell of its body. Every tide of
autosome was marked with a number starting from number 1 up to 22, but in DS patients
there is an extra chromosom in chromosom 21. According to the etiology, DS can be divided
into three types, i.e. full, mosaic, and translocation.9,11
Most of the patients show Full trisomy 21, but some of them are normal, mosaic and
translocation, while the majority of children with DS had full trisomy 21. 2,11,12In patients
with this type of DS, there are 47 chromosomes in every cell of their body, with excess at
chromosome 21 as a result of a process called " non-disj unction", and mental retardation is
commonly found in such a patient. Patients with the mosaic type have two kinds of cell
population in their body. Some of the cells consist of normal chromosome complement with
only having two chromosomes 21, while the others have two and three chromosomes 21
Hypodontia in Mosaic and Full Down
The mosaic form is a disparity type between Down syndrome and the normal
condition. When there is only a few/little of trisomy cells in the body, is is often difficult to
determine from the existing clinical signs whether someone suffers DS or not. The more cells
there are with normal chromosome proportion, the more possibility that can be seen of a
normal visible child, so the bigger the cell proportion with normal chromosomes, the higher
the possibility of a normal appearance.9,11
A child with is trisomy 21 mosaic has a normal chromosome complement in some of
his/her cells. He/she may have fewer of the physical characteristics, there will be a population of
cells with both normal and trisomy chromosome numbers and there will be a mixture of 46 and
47 chromosome cells and better mental performance.1,9
Translocation is the transfer of segments among non-homolog chromosomes or loss
of some segments from a chromosome, some of which are segments from a chromosome.1,12
The clinical features of Down Syndrome patients may appear as low birth weight,
body height below normal, microcephaly, flat occiput, flat facies, low set and small ears, soft
and straight hair. There is also slanting of the eyes with/and brustifields iris, broad nose and
nose bridge, the hands are metacarpal and phalanges, syndactily, clinodactyly, and simian
crease. A sandal gap can be found between the first and second toes of the feet. 2,7,9,1 1The
most frequent oral signs are macroglossia, fissured and geographic tongue, high arched
palate, (high vault) and generalized hypotonia.2,8,9Another features are high caries prevalence
and periodontal disease.
DS patients have delayed body and dental development, and usually there is a delay in
exfoliation of the primary teeth, while some teeth may be congenitally missing. Eruption of
the teeth are often small and or hypoplasia. Delayed eruptions occur in both deciduous and
permanent dentitions. The size of the teeth are smaller than normal and could be cone-shaped in
the incisors and hypoplastic in the molars.2,7,9,11
The.aim of this study was to find the occurrences of hypodontia in Down syndrome
1 8 6 Forum 11miahX-2011 FKG USAKTI
Figure 1. Hypodontia in Down syndrome
Subject and Method
A number of 26 DS patients consisted of 18 full type and 8 mosaic type were included
in this cross sectional study. The patient's age ranged between 8- 12 years and have been
diagnosed as Down syndrome by a pediatrician. The DS confirmation was based on clinical
features and chromosomal analysis with karyotyping to determine mosaic and full Down
syndrome.
Mosaic is determined when there are >40% normal cells (46 chromosomes) and full is
determined when there are < 40% normal cells. Down syndrome including the types were
diagnosed by a pediatrician.
H ypodo nt i a was det er mi ned w hen one or mor e t eet h ar e mi ssi n g i n each j aw,
reassured by radiographic examination. Chi square was used for data analysis. The results can
be seen in table 1.
Results
Table 1. Sample distribution based on occurrences of missing teeth/hypodontia
D o w n
N Normal with Syndrome Hypodontia
Mosaic 8 7( 26%) 1(6%)
Full 18 11(42%) 7(26%)
Total 26 18 8
Hypodontia in Mosaic and Full Down Syndrome Patients187
The result showed that hypodontia occured in one mosaic patient (6%; 1 from 8
patients) and 8 full patients (26%, 7 from 18 patients). Table 1 shows that hypodontia occur
more often in full type patients, and both in mosaic and full type DS. According to some
authors,3,8 hypodontia in this study is associated with Down Syndrome. The clinical dental
manifestation of Down Syndrome patients are delayed eruption both in deciduous and
permanent teeth, conically shaped and missing/hypodontia of the teeth. Based on karyotype,
in this study we also found hypodontia more often in full type of DS and it is in accordance
with the statistical analysis using Chi square.
Table 2 Sample Distribution Based on Missing Teeth Affected
Mosaic Trisomy Full Trisomy
Il 12 C P1 P2 MI M2 Il 12 C P1 P2 MI M2 Maxila 0 1 0 0 0 0 0 0 0 0 0 0 0 0
Mandibula 0 4 0 0 1 0 0 0 3 0 0 2 0 0
Note: 11: First incisive P2: Second premolar 12: Second incisive M I: First molar
C: Cuspid M2: Second molar
P 1: First premolar
Table 2 shows that the majority of missing teeth is the lateral maxilla incisors. In the
mosaic type, only I patient had 1missing tooth. And in the full ty-pv, (7 patkow3). 4Vaticuo)
had 1 missing tooth, and 3 patients had 2 missing teeth.
In the mosaic type only 1 patient showed 1 missing tooth, that is the maxillary lateral incisor.
And in the full type, there were 4 missing maxillary lateral and 3 mandibular incisors, 1
missing maxillary second premolar, 2 missing mandibular second premolars.
Discussion
Developmental absence of the teeth is one of the most common dental development
abnormaiities. Hypodontia occurs because of failure of the induction of the oral ectoderm by
ectomesenchym.3,8 It might also be caused by disruption of the dental lamina, abnormalities
188Forum llmiah X- 2011 FKG USAKTI
Alterations in tooth number result from the problem during the initiation or forming
of the dental lamina stage in teeth development. In addition to hereditary patterns, other
Famous that effect toot number are physical disruption of the dental lamina and failure of the
dental lamina inductions.5
The aetiology of hypodontia in most cases is obscure. An increased frequency of
hypodontia has been reported in association with low birth weight, multiple births, and
old/increased maternal age (> 35 years). Delayed dental development may be found in DS
patients.13 In this study, hypodontia occured more often due to the lateral incisor delayed
dental development. Hypodontia in full type was also accompanied by peg shaped teeth, and
this is in accordance with Heasman that the presence of peg/conical teeth is often associated
witn ttie absence of the teeth in the opposite side, it occured in 3 from 18 full type patients.8
The mosaic type has different prognostic appearance. Delayed dental development,
deciduous teeth eruption, peg shaped/microdontia in the maxillary lateral incisors occur more
often in the full type in spite of the mosaic type. 13,14.15The mosaic type has a combination of
normal karyotype and DS, has more normal chromosomes in the cell than in trisomy cells. In
this study hypodontia in the mosaic type was found in only I from 8 patients and thefull
type in 7 from 18 patients.
The maxillary lateral incisor, lower incisor, second premolar are the most common
missing teeth in this syndrome.6 Based on the affected teeth, the maxillary and mandibular
lateral incisors were the most common missing teeth.
Conclusion
Hypodontia occurs in DS patients, both in mosaic and full DS, and oftenly in full type
DS. The lateral incisor is the most affected tooth.
Sugestion
It is suggested that further researches should be done to find out the degree of DS
caryotype in delayed dental development.
References
Hypodontia in Mosaic and Full Down Syndrome Patients189
2. Laskaris G. Color Atlas of Oral Disease in Children and Adolescents. New York: Thieme; 2000: 12-4,158 -9.
3. Neville et al. Oral and Maxillofacial Pathology. 2ndedition. Philadelphia : Saundres;
2002: 69-71.
4. Cameron AC, Widmer.Handbook of Pediatric Dentistry. 2ndedition. Philadelphia: Mosby,2003; 184-6.
5. Pinkham et al. Pediatric Dentistry Infancy through Adolescence.4thedition. Missouri: Elsevier, 2005; 63-9,263.
6. Arte S, Pirinen. Characteristic of incisor-premolar Hypodontia in Families. J Dent Re 60: 1445-50. 2001.
7. Welburry, Richard R. Pediatric dentistry.2dedition. Oxford University,2001;274-5,394- 6.
8. Heasman. Master Dentistry Vol. 2. Istedition.Churchill Livingstone, 2009; 208.
9. Smith and Wilson. The Child with Down syndrome. WB Saunders company, 1973 38,2 1 -4,30-1.
10. Nowak AJ. Dentistry for the handicapped patient. CV Mosby Company, 1976; 46-8„74
-5.
11. Jones. Smith'sRecognizable pattern of Human Malformation. W B Saunders company, 2006;7-9.
12. Thompson and Thompson.Genetic in Medicine.W B Saunders Company, 2001; 157-9.
13. Syarief W, Oewen R. Down Syndrome Perspective pediatric dentistry. Journal of The
Indones Dent Assoc, 150-4; September 2002.
14. Syarif W. Decideous Teeth Eruption in Mosaic and Full Down Syndrome patient. Dental J Unair 38(4):183-4. 2005
