Anomalous Findings of Number , Morphology and Size of Permanent Teeth in 7 – 10 Years Children Living in the Czech Republic

6,043 children, who were ordinary patients and children of Caucasian population, were examined clinically and radiographically. 430 children were aged 7–10 years. Dental anomalies were diagnosed in 14.1% (61 children) of those observed between 7–10 years. We aimed at numerical anomalies (78.6% of children with anomalies), morphological anomalies (19.6% of children with anomalies), size anomalies (3.2% of children with anomalies) and combinations of diagnoses (1.4% reflects the combinations of teeth 2 times calculated in combinations of diagnoses). Congenital numerical variations, i.e. hypodontia and hyperodontia, are among the most common deviations of the permanent dentition. Both conditions can occur as isolated traits or in association with other syndromes. Many studies indicate that hereditary factors are involved in the aetiology of anomalies. Gen MSX1 involves a primary position in mediating interactions between epithelium and mesenchyme in the development of teeth. Occurrence of dental anomalies is not very frequent; problems can arise with diagnosis of those affected teeth. It can be done using Orthopantomogram or Computed Tomography and 3D reconstruction. Some of the children with anomalies may have difficulties in treatment of affected teeth but in most cases the prognosis is good. This study was supported by the project IGA MZCR No. NT: 13351-4. Mailing Address: Prof. Taťjana Dostálová, MD., PhD., DSc., MBA, Department of Stomatology, Second Faculty of Medicine, Charles University in Prague and University Hospital Motol, V úvalu 84, 150 06 Prague 5, Czech Republic; Phone: +420 224 443 100; Fax: +420 224 443 102; e-mail: tatjana.dostalova@fnmotol.cz


Introduction
Prevalence of dental anomalies and their demonstration was the aim of this study; dental anomalies are not rare and they are interesting.Literature gives different information on the number of dental anomalies (Marková and Teichmanová, 1985;McNamara et al., 1998;Backman and Wahlin, 2001;Merglová and Kilian, 2002).Many studies indicate that hereditary factors are involved in the aetiology (Sottner, 1997;Peck et al., 2002;Kouskoura et al., 2011).Gen MSX1 involves a primary role in mediating interactions between epithelium and mesenchyme in the development of teeth (Sottner, 1997;Kouskoura et al., 2011).Deletion of this gene brings about tooth agenesis (Peck et al., 2002;Kouskoura et al., 2011).About 80% (excluding the third molars) of hypodontia patients miss one or two teeth (Kouskoura et al. 2011).According to Garib et al. (2009Garib et al. ( , 2010) ) prevalence rate of agenesis of permanent teeth has significantly increased: maxillary lateral incisors agenesis and lower second premolars agenesis.
We report the year 2011 when we treated 6,043 children.Children were of the Caucasian population, aged from birth to 18 years and represented our regular patients.The 430 children aged 7-10 years were examined clinically with radiographic imaging (Pasler and Visser, 2003) and Orthopantomogram (OPG) (Figure 1); in those with diagnostic problems the intraoral radiographs (Figure 2) or Computed Tomography (CT) (Figure 3) and 3D (Figure 4) were obtained.We observed all the permanent teeth, third molars excluded.Dental anomalies were diagnosed in 61 children from the total of 430 children.
The tooth 22 was partly erupted and appeared healthy at the time of the clinical examination.The radiographic examination revealed the dens in dente in the maxillary left lateral incisor.The CT radiographic consultation was completed for the remainder of the tooth.This is: 1.6% of affected children and 0.2% of all examined children.2.5.Taurodontism was not found.

Discussion
We examined 430 children 7-10 years old at our study and 61 (14.1%) of them had some dental anomalies.Uslu et al. (2009) found in orthodontic patients 40.3% of patients with dental anomaly.The numerical anomalies are the most prevalent according to the literature (Backman and Wahlin, 2001) and we also confirmed it in our study.According to the literature numerical variations are of the multifactorial 120) origin, genetic and environmental factors probably participate (Brook, 1984;Sottner, 1997;Backman and Wahlin, 2001;Peck et al., 2002;Kouskoura et al., 2011).The prevalence of hypodontia is 54.1% of all affected children, which is the highest number of one diagnose in our study.33 cases with hypodontia represent 7.6% of all examined and 54.1% of affected children.Backman and Wahlin (2001) in their study found hypodontia in Swedish population in 7.4% of visited children.The highest occurrence of hypodontia is in Denmark 8.2%, and the lowest is in England 4.4% (Brook, 1984;Aasheim and Ogaard, 1993;Endo et al., 2006); agenesia was the most common with 7.4% of all examined children by Gupta et al. (2011) 4.19%.The most frequently affected teeth by hypodontia in our children are the permanent lower second premolars; in the literature are the same data (Garib et al., 2010).The most frequently missing teeth in hypodontia group according to our study were incisors 1 and 2, similarly to the study of Endo et al. (2006).The second place belonged to the permanent upper second incisors.By Larmour et al. (2005) patients with Down syndrome have a high prevalence of hypodontia.All our patients with hypodontia had no underlying diseases and they were healthy.The hypodontia is most frequent in girls (57.5% in our study) the same information about higher frequency in girls is also found in the literature (Brook, 1984).The highest number of missing teeth due to hypodontia was 6 teeth: in two girls.One boy with oligodontia did not have 8 teeth.Prevalence of hyperodontia in all examined children is 3.4%; Backman and Wahlin (2001) found 1.9%, in all affected children is 24.5%.The most frequent supernumerary tooth (Brook et al., 2009) is mesiodens, 62, 5% of all supernumerary teeth in our study, in the literature (Backman and Wahlin, 2001) it is 78%.In the literature it is possible to find a difference in the number of mesiodentes in relation to sex, Brook (1984) had higher number for boys; Backman and Wahlin (2001) described higher number in girls.In our study the same number of girls and boys with mesiodens was revealed.The highest number of supernumerary teeth is 4 teeth in one patient.Morphological anomalies were diagnosed in 12 children; this is 2.7% of all examined children and 19.6% of all affected children.There were diagnosed 8 peg-shaped lateral upper incisors in 7 children, this is 58.3% of morphological anomalies and it is the most common type in all morphological anomalies.Peg-shaped teeth at both sides occurred in one boy.We observed one girl with the coexistence of a lateral peg-shaped upper right tooth and microdontia in the same location but at the left side.In the literature the coexistence of pegshaped upper lateral incisor and hypodontia is described (Backman and Wahlin, 2001) differs according to various authors.The data are from 0.25% to 10% by Chen et al. (1998), by McNamara et al. (1998) to range from 0.25% to 6.9%, by Backman and Wahlin (2001) the prevalence is about 6-8%.The prevalence of dens in dente is 0.2% of all examined children in our study.The permanent maxillary lateral incisors should be the most frequently affected teeth according to Alani and Bishop (2008).Our dens in dente was also found in the permanent maxillary lateral incisor.Megadontia is more common in boys and microdontia in girls (Brook, 1984).The same result revealed also our monitoring.In the literature various combinations of diagnoses by dens in dente are given (Backman and Wahlin, 2001); in our study we found only combination of dens in dente with microdontia.Most of combined diagnoses in our study include hyperodontia.

Conclusion
Dental anomalies should be solved by dental treatment.Problems can arise in the treatment of these affected teeth.In most cases the treatment prognosis is good.The treatment must be modified in many cases.Emphasis is placed at the appropriate prosthetic treatment of the affected teeth and solution of articulation disorders.

Figure 5 -
Figure 5 -Place of missing teeth in upper and lower jaws.

Table 5 -Talon cusps
4. Combinations of diagnoses (Table6): were diagnosed by 4 children.This is: 6.5% of affected children and 0.9% of all examined children.

Table 6 -Combinations of diagnoses
(McNamara et al., 1998)et al. (1998)talon cusps occur in 90% in the maxilla and at the maxillary lateral incisor on the palatal surface.It can by an isolated finding or the anomaly could combine with other dental anomalies.Our 3 children had the talon cusps only in maxilla and only by the maxillary central incisors at the palatal surface; one boy had talon cusps at both of them.According to the literature(McNamara et al., 1998)and also in our study tubercles of Carabelli were diagnosed in maxillary first permanent molars.The indicated prevalence of dens in dente