|Year : 2020 | Volume
| Issue : 1 | Page : 15-24
Prevalence of dental anomalies in a sample of orthodontic Egyptian patients using orthopantograms
Fady H. Fahim, Dina O. ElAbbasy MSc, PhD
Department of Orthodontics, Cairo University, Cairo, Egypt
|Date of Submission||25-Aug-2019|
|Date of Acceptance||05-Dec-2019|
|Date of Web Publication||20-Jun-2020|
Dina O. ElAbbasy
Springs 8, Street 6, Villa 40, Dubai, PO Box 940404, United Arab Emirates
Source of Support: None, Conflict of Interest: None
The aim of this cross-sectional study was to investigate the prevalence of dental anomalies in a sample of Egyptian orthodontic patients.
Patients and methods
This is a retrospective study where 435 digital orthopantograms taken of patients, ranging in age from 14 to 30 years with a mean age of 19 years were studied. The patients were presented for treatment at a private practice in Cairo during the period from 2017 to 2019. The orthopantograms were reviewed for impactions (including and excluding third molars), congenitally missing teeth or hypodontia (including and excluding third molars), ectopic eruption, microdontia (peg-shaped and small-sized maxillary lateral incisors), rudimentary 8's, root dilacerations and supernumerary teeth.
Excluding third molars, the number of patients that had at least one dental anomaly was 183 or 42.1%. The prevalence of patients with impacted teeth was 66 (15.2%), while the prevalence of congenitally missing teeth was 44 (10.1%). Equal prevalence between males and females was recorded for impacted maxillary permanent canines (M = 16, F = 16) and congenitally missing maxillary permanent canines (M = 1, F = 1). The least prevalence were microdontia (n = 15, 3.4%), dilacerated roots (n = 8, 1.8%) and supernumerary teeth (n = 8, 1.8%). Rudimentary wisdom teeth count was 12 (2.8%) out of the total sample with only maxillary third molars being affected. The prevalence of impacted third molars was 25% (n = 109, M = 27, F = 82). The prevalence of congenitally missing third molars (at least one missing third molar) was 19.3% (n = 84, M = 22, F = 62). Females showed higher prevalence than males for all anomalies except for impacted mandibular permanent canines where males were higher than females (M = 9, F = 5), impacted upper incisors and upper first premolars (M = 1, F = 0) and supernumerary teeth (M = 6, F = 2). The prevalence of patients with impacted permanent second molars was 4.6%.
Excluding third molars, the most common dental anomaly was impaction followed by teeth agenesis. The most prevalent impaction was the maxillary permanent canine and the most congenitally missing teeth were the maxillary lateral incisors. Root dilacerations and supernumerary teeth were the least common anomalies. Congenitally missing and impacted third molars constitute a large segment of dental anomalies and must be evaluated separately. A large variation exists between the different populations regarding the prevalence of the various anomalies.
Keywords: dental anomalies, Egypt, hypodontia, impacted teeth, orthodontic patients, prevalence, supernumerary
|How to cite this article:|
Fahim FH, ElAbbasy DO. Prevalence of dental anomalies in a sample of orthodontic Egyptian patients using orthopantograms. Tanta Dent J 2020;17:15-24
|How to cite this URL:|
Fahim FH, ElAbbasy DO. Prevalence of dental anomalies in a sample of orthodontic Egyptian patients using orthopantograms. Tanta Dent J [serial online] 2020 [cited 2020 Jul 9];17:15-24. Available from: http://www.tmj.eg.net/text.asp?2020/17/1/15/287096
| Introduction|| |
Dental anomalies are defined as aberrations in the number, size, shape, position and structure of the teeth. One or more teeth may be affected. Etiology includes both genetic and environmental factors. They can also be a manifestation of some systemic disorders or syndromes. Besides being esthetically unappealing, they cause disruptions in the maxillary and mandibular dentition which affects the occlusion and hence can influence orthodontic treatment planning. Accordingly, thorough clinical and radiographic investigation for the diagnosis of anomalies is crucial to avoid malocclusion as well as other dental problems such as caries and periodontal pathologies ,,.
Anomalies of teeth number include hyperdontia (supernumerary teeth), oligodontia (absence of six or more teeth excluding third molars) and hypodontia. Hypodontia (dental agenesis or congenitally missing teeth) is one of the most common dental anomalies (~25% of the population) with the third molar being the most affected tooth (20.7%) ,. There has been great variation in the literature among the different populations with regards to the prevalence of anomalies. For instance, the prevalence of congenitally missing teeth, excluding the wisdom teeth is 4.3–7.8% with the lower second premolars constituting the most frequently missing teeth, followed by the maxillary lateral incisors and then maxillary second premolars . Other studies reported maxillary lateral incisors as the most frequently congenitally missing teeth ,. This wide variation exists mainly due to differences in racial and ethnic backgrounds and occasionally due to difference in study designs, criteria, of selection, methods of measurements and sampling techniques.
Aberrations in teeth size include macrodontia (teeth that are physically larger in size than normal) and microdontia (teeth that are physically smaller in size than normal) such as peg-shaped laterals. Teeth shape anomalies may affect the root and result in germination, fusion, dilaceration, taurodontism, concrescence or affect the crown resulting in dens invaginatus, dens evaginates and talon cusp. Dental anomalies of tooth structure are amelogenesis and dentinogenesis imperfecta.
Genetic factors have been identified with respect to mutations in AXIN2, PAX9 and MSX1 in families having congenitally missing teeth. Environmental factors result in disturbances during the morpho-differentiation and the histodifferentiation stages of tooth development. Disturbances during the morpho-differentiation stage cause anomalies in tooth size, shape and number while tooth structure anomalies occur as a result of disruption during the histodifferentiation stage ,.
Finally, anomalies of tooth position are demonstrated in impacted teeth whereby impacted permanent maxillary canine is considered the most significant. The development of the permanent maxillary canines occurs high from the dental arch in proximity to the nasal cavity thereby having a long eruption path compared to other permanent teeth. This makes it highly prone to impaction which can be either buccal or palatal. The etiology appears to be genetic in origin .
Previous studies have reported an association between certain types of dental anomalies which exist in the same patients. In individuals with missing third molars, the prevalence of other congenitally missing permanent teeth was 13 times larger than patients without missing third molars. Similarly, the prevalence of palatally impacted canines was higher in patients with peg-shaped maxillary lateral incisors and reached around 34% . This suggests a common genetic origin.
To our knowledge, the studies on the prevalence of developmental anomalies in the Egyptian population are limited and usually do not address a broad scope of the anomalies. Hence, the objective of this study was to study the prevalence of a large variety of dental anomalies in a group of Egyptian orthodontic patients.
| Patients and Methods|| |
The retrospective study included patients who attended the orthodontic clinic of a private practice in Cairo, Egypt between 2017 and 2019. The age range of the sample was 14–25 years. A total number of 1500 cases of both males and females were initially screened and inclusion criteria were applied as follows:
- Egyptian patients.
- No history of previous orthodontic treatment or extraction.
- No past history of trauma.
- No syndromes such as ectodermal dysplasia or Down syndrome.
- No cleft lip and palate.
- No systemic diseases.
- Good quality pretreatment records including panoramic and lateral cephalometric radiographs.
All Patients are informed about the aim of the study and signed to be participated in this research according to the ethical committee of Cairo University.
After the inclusion criteria were applied, the sample consisted of 435 cases of whom 30.4% were males (n = 132) and 69.6% were females (n = 303).
The orthodontic records and radiographs were reviewed. The digital panoramic radiographs were inspected under adequate lighting conditions by single investigator using standard screen brightness for the following developmental anomalies:
Teeth number anomalies are hypodontia or congenitally missing teeth and hyperdontia (such as supernumerary teeth and supplemental teeth). Teeth size and shape anomalies are microdontia (peg-shaped upper lateral incisors, small-sized upper lateral incisors), rudimentary third molars, dilaceration. Since the presence of microdontia is difficult to confirm on orthopantograms, evaluation of intraoral photographs was done for patients suspected to have microdontia. Teeth position anomalies includes impaction. Microdontia is a tooth identified in this category had a size smaller than its antimere . An example is peg-shaped maxillary lateral incisors. Dilaceration is identified on the radiographs when there was a bend or angulation at the junction of the crown and the root or along the length of the root. Impaction was identified when a tooth remained unerupted and did not reach its normal functional position because of deflection from its eruption path or presence of a physical barrier ,,,. Impacted teeth were diagnosed based on the criteria implemented by Lindauer et al. .
Furthermore radiographic examination was done to confirm the position of impacted teeth specifically the maxillary canine ,. Other teeth under investigation were second premolars, permanent second molars and third molars. Identification of impacted third molars was done according to the classification of Pell and Gregory and Winter's classification.
Impacted, congenitally missing and rudimentary wisdom teeth were investigated and separate statistics were done. Associations between the different types of dental anomalies were also identified, recorded and statistically analyzed.
All data were collected, tabulated and subjected to statistical analysis. Statistical analysis was performed by SPSS in general (version 17), while Microsoft Office Excel was used for data handling and graphical presentation. Qualitative categorical variables were described by proportions and percentages. For comparing two proportions z test was applied. Significance level was considered at P value less than or equal to 0.05 (S); while for P value less than or equal to 0.01 was considered highly significant (HS). Two tailed tests were assumed throughout the analysis for all statistical tests.
| Results|| |
Out of 435 patients (M = 132 or 30.4%, F = 303 or 69.6%), a total of 276 (63.4%) patients had at least one dental anomaly while 159 (36.5%) had no anomalies. The number of patients who had at least one dental anomaly excluding third molars was 183 (42.1%).
The most prevalent dental anomaly was teeth impactions which, excluding third molars was 15.2%. The most common impacted teeth were maxillary permanent canines followed by impacted lower permanent canines. Next were impacted permanent second molars followed by impacted lower second premolars. Similar prevalence was recorded for upper incisors, upper first premolars and second premolars. No patients with impacted lower first premolars were observed [Table 1].
The next most prevalent anomaly was congenitally missing teeth which, excluding third molars was 10.1% of the total sample [Table 2]. The rate of agenesis was higher in females than in males. The most common congenitally missing teeth were maxillary lateral incisors with unilateral agenesis more frequent than bilateral agenesis and females more prevalent than males [Table 3]. The second most common congenitally missing teeth were lower second premolars. The third most common agenesis was upper second premolars. Congenitally missing upper permanent canines constituted 0.8% of the total sample. The least common teeth agenesis were lower permanent second molars and lower permanent lateral incisors with a prevalence rate of 0.2%.
|Table 2: Prevalence of patients with congenitally missing teeth in the orthodontic sample|
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|Table 3: Distribution of congenitally missing maxillary lateral incisors teeth|
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Excluding rudimentary wisdom teeth, microdontia was observed in 3.4% of the total sample. 2.5% were small-sized maxillary lateral incisors and 0.9% were peg-shaped maxillary lateral incisors [Table 4].
|Table 4: Prevalence of microdontia with respect to number of teeth in the orthodontic sample|
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Rudimentary wisdom teeth count was 12 out of the total sample with only maxillary third molars being affected. No rudimentary lower third molars were documented therefore, the difference was highly significant (P < 0.001). Equal prevalence was found between right and left wisdom teeth [Table 5].
|Table 5: Prevalence of rudimentary wisdom teeth with respect to number of teeth in the orthodontic sample|
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The prevalence of root dilaceration and supernumerary teeth were identical with females more prevalent than males in dilaceration while for supernumerary teeth the prevalence in males was higher than females [Table 6].
|Table 6: Prevalence of supernumerary and dilacerations in the orthodontic sample|
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The prevalence of patients with impacted permanent second molars was 4.6%. When calculating the prevalence of impacted permanent second molar with respect to number of teeth, the prevalence of lower second molar impaction was significantly higher (P < 0.05) in the lower arch than the upper arch [Table 7].
Patients with impacted wisdom teeth constituted 25% of the total sample [Table 8]. According to the classification of Pell and Gregory , for all impacted third molars, the highest pattern of impaction was IIB (Class II, position B) [Figure 1]a, [Figure 1]b, [Figure 1]c, [Figure 1]d.
|Table 8: Prevalence of impacted and congenitally missing permanent third molars in the orthodontic sample|
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|Figure 1: (a) Prevalence of impaction of UR8 in the orthodontic sample. (b) Prevalence of impaction of UL8 in the orthodontic sample. (c) Prevalence of impaction of LR8 in the orthodontic sample. (d) Prevalence of impaction of LL8 in the orthodontic sample.|
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Patients who had at least one congenitally missing third molar were 84 which is 19.3% of the total sample [Table 8]. However, according to the number of missing third molars, the prevalence was insignificant between the upper and lower molars (P > 0.05) [Table 9].
|Table 9: Prevalence of congenitally missing permanent maxillary and mandibular third molars in the orthodontic sample|
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Regarding an association between impacted third molars and impacted permanent canines, there was no correlation between these anomalies. The prevalence of patients with impacted maxillary canines without impaction of wisdom teeth is statistically significantly higher than patients with both teeth impacted (P ≤ 0.01) [Table 10].
|Table 10: Association between prevalence of impacted permanent canines (3 s) and wisdom teeth|
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Number of patients with missing wisdom teeth only were found to be highly significant (P < 0.001) than number of patients with missing wisdom teeth with other teeth [Table 11].
|Table 11: Prevalence of patients with missing third molars only versus missing third molars (8 s) with other teeth missing|
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The number of patients with more than one congenitally missing third molar accompanied by other missing teeth were significantly higher (P < 0.001) than those with missing only one third molar combined with other congenitally missing teeth [Table 12]. The most commonly congenitally missing tooth that occurred in association with third molar agenesis was the maxillary left lateral incisor [Figure 2].
|Table 12: Prevalence of patients with missing wisdom teeth and other teeth missing|
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|Figure 2: Prevalence of other teeth missing in cases with congenitally missing third molars in the orthodontic sample.|
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| Discussion|| |
Studies on the prevalence of dental anomalies in the Egyptian population have been sparse. Our study was designed to examine the prevalence and distribution of the different types of developmental dental anomalies in 435 Egyptian patients attending a private practice in Cairo during the period from 2017 to 2019. The cut-off age for this study was 14 years old since absence of the third molar cannot be confirmed in all cases until the 14th year (i.e. the critical age) .
The presence of dental anomalies should be adequately investigated during orthodontic diagnosis and taken into consideration during treatment planning to avoid any complications in orthodontic treatment . Many studies indicated genetic and hereditary factors in the etiology of dental anomalies of position, size, number, as well as timing of development. This was obtained from research in families, monozygotic twins, and from the common observation of associations of some types of dental anomalies ,,.
In the current study, the total number of patients with at least one dental anomaly was 63.4%. Excluding third molars, the prevalence of patients with at least one dental anomaly was 42.1%. The prevalence of dental anomalies in orthodontic patients in different populations shows a great divergence. Although our results matched a few previously published epidemiological studies, significant differences existed as well with others. For example in a sample of Japanese orthodontic patients the prevalence was 74.77% . They included small sample sizes (111 patients) all of which were orthodontic patients seeking consultation for esthetic reasons. Therefore, small sample sizes are unreliable in such epidemiological studies.
The prevalence rate in our study was higher than the one reported in the Egyptian population study by Montasser and Taha  (32.6%) on 509 patients. In the study by Uslu et al. in the Turkish population the prevalence was 40.3%. In the Saudi population study by Afify and Zawawi the prevalence of patients with at least one dental anomaly was 45.1%, however this value is not indicative as they included third molars in their sample. Moreover their study had limitations in that the classification and angulation of third molar impaction was not considered.
In another study of the Turkish population by Altug-Atac and Erdem , the prevalence was significantly lower where only 5.46% had at least one dental anomaly. On the other hand, the study of Goncalves-Filho et al.  in the Brazilian population revealed a prevalence of 56.9%. These differences could be due to different ethnic backgrounds of the study samples as well as study designs. Moreover, they can also be related to different environmental factors.
The etiological factors causing teeth impactions or ectopic eruption are either genetic or environmental. Environmental causes are mainly due to early extraction of deciduous teeth without space maintenance which leads to tooth size-arch length discrepancy. Besides space loss, early extraction of the primary teeth leads to alterations in the keratinized gingival tissues in long-standing edentulous regions thus preventing the eruption of the permanent teeth . Early detection of anomalies of impaction may help achieve timely interceptive provisions to prevent its occurrence, such as extraction of the primary canines, rapid palatal expansion and cervical pull headgear ,,. This intervention is important to avoid risks of impaction which include malocclusion, root resorption of adjacent teeth as well as development of cysts ,. To determine the prevalence of impactions in the sample without duplication, patients with more than one impacted tooth were calculated as one patient (regardless of the number/type of impacted teeth).
Because of the high prevalence of impacted wisdom teeth in the different populations and to avoid overestimation of the prevalence of impacted teeth, the impacted wisdom teeth were evaluated separately. In this study, impaction was the most common dental anomaly whereby the number of patients with impacted teeth excluding third molars were 15.2% whereas with third molars included, the prevalence rose to 37%. Similar to this study, impactions were the most common dental anomaly in the study by Montasser and Taha  in the Egyptian population who stated a lower incidence rate of 12.8%. Likewise, Silva Meza , Diaz-Perez and Echaverry-Navarrete  and Herrera-Atoche et al.  indicated the same finding. There is a high impact of environmental factors on the prevalence of dental anomalies, thus resulting in impaction being the most frequent anomalies. The most common impacted teeth in our study were maxillary permanent canines and equal distribution between males and females. This goes in agreement with other studies ,,,,. Some studies reported an increased prevalence of impacted maxillary canines in females ,. However, in our study there was no statistically significant difference between males and females regarding maxillary canine impaction.
Afify and Zawawi  reported a lower prevalence rate than our study for impacted maxillary canines but recorded them to have the highest rate of impaction following wisdom teeth. However, in the study by Montasser and Taha  the mandibular second premolars were the most commonly impacted teeth followed by impacted permanent maxillary canines. The incidence of impacted lower second premolars in this study was the fourth in frequency and was significantly lower than Afify and Zawawi  who reported a prevalence rate of 0.6% for impacted lower first premolars and 1.4% for impacted upper and lower second premolars.
Previous studies demonstrated the rarity of impacted lower permanent canines with either zero prevalence or prevalence in the ranges of 0.1–0.3% ,,. In our study, impacted lower cuspids were the second most frequent anomaly reaching 3.2% with more prevalence in males than females.
The prevalence of wisdom teeth impaction in this study was 25% with higher frequency in females than males. The most common type/pattern of impactions was Class II position B (IIB). Impaction rate of third molars in the Saudi population was similar to ours (21.2%) .
From an evolutionary perspective, there has been a decline in the number of teeth and the size of the jaws in modern human populations along with decreases in the surface area needed for mastication. It is considered that evolution in regard to reduction in tooth numbers will continue ,. In the literature, excluding third molars, the prevalence of teeth agenesis is between 0.3 and 10.1 . The prevalence of congenitally missing teeth in this study excluding third molars was 10.1% with a female: male ratio of 3: 1. This is higher than the previously reported prevalence of 2.4% in the study of the Egyptian population by Montasser and Taha  who also noted an almost equal distribution between males and females (2.5 and 2.3%, respectively). Similar to our study is the study by Endo et al.  in the Japanese population who reported a percentage of 8.5% of hypodontia (9.3% for females and 7.5% for males). Nordgarden et al.  also discovered higher prevalence of hypodontia in females than males (5.1% of females and 4.0% of the males). In agreement with the results of our study is the one by Afify and Zawawi  who reported a prevalence of 9.5% in the Saudi Arabian population for congenitally missing teeth, however it was the most prevalent anomaly and not impaction as in our study. Higher prevalence of 21.6% of congenitally missing teeth (most common dental anomaly) was reported in Turkish orthodontic patients in the study by Uslu et al.  There is a higher likelihood of greater prevalence of agenesis in orthodontic patients than the general population ,,. Rose  showed that 4.3% had at least one congenitally missing tooth.
There is high evidence that genes play a crucial role in the etiology of hypodontia. Grahnén  observed in a study of patients with congenitally missing teeth that over 50% of siblings and relatives had hypodontia which is a large percentage in comparison with the general population. Moreover, Vastardis  investigated the members of a large family who had congenitally missing second premolars and third molars and detected mutation of gene MSX1 on chromosome 4p.
The type of missing teeth vary according to the population and ethnic background. In this study, excluding wisdom teeth, agenesis of the maxillary lateral incisors was the most prevalent. Unilateral occurrence was more predominant than bilateral. In the study by Uslu et al.  excluding the third molar, agenesis was also found most frequently in the maxillary right lateral incisor (2.6%). In another Turkish study by Altug-Atac and Erdem , the prevalence rate of congenitally missing maxillary lateral incisors was 1.74%, of these 72% were missing both upper lateral incisors and 28% were missing only one lateral incisor. Contrary to our findings, another study of the Saudi Arabian population reported lower premolars as the most common congenitally missing teeth .
The second most commonly missing teeth are the mandibular second premolars. This is in accordance with the results of the study by Silva Meza  who reported a rate of 2.7%. In the United States of America it is mandibular second premolars that is the most abundant teeth exhibiting agenesis . Likewise in studies of the Japanese and Norwegian populations the lower second premolars were the most commonly congenitally missing teeth ,. Similar to the Arab population is the Turkish population where maxillary lateral incisors are also most frequently missing . They reported a prevalence rate of 1.74% with bilateral agenesis more frequent than unilateral agenesis (72% compared to 28%, respectively). This was in agreement with other studies . Different to our findings are studies in Europe whereby the most commonly missing teeth are the maxillary second premolars .
In our study, the prevalence of congenitally missing upper second premolars was higher than maxillary permanent canine. The congenitally missing lower lateral incisor and lower second molar had the least prevalence.
Concerning third molars, out of the total sample, 19.3% had agenesis of at least one wisdom tooth with higher frequency in females than males. This is in line with the results of Montasser and Taha  of the Egyptian population who noted an incidence rate of 15.3% but equal male and female prevalence. However, they declared a higher rate of agenesis for the maxillary molars in the ratio of 1.5: 1.0 which is in accordance with the study of Kazanci et al. . Nonetheless, the prevalence rate reported by Kazanci et al.  was much higher (23.8%). This confirms that absence of third molars is the most common agenesis in the population .
The prevalence of microdontia in this study excluding rudimentary third molars was 3.4%. The most commonly affected teeth were the upper lateral incisors with a prevalence of 2.5%. This is in agreement with other studies ,. Peg-shaped laterals comprised 0.9% of the sample with equal distribution between the right and left sides while small-sized maxillary lateral incisors constituted 2.5% of the total sample. A similar prevalence was reported in the Egyptian population study by Montasser and Taha  (2.0%) with the maxillary lateral incisors being the most affected teeth. Peg-shaped lateral incisors comprised 75% of the teeth affected with higher predilection on the left side than the right side. They proposed a genetic predilection of microdontia as they observed macrodontia in the adjacent tooth. It has been indicated that the predominance of microdontia rises over time due to the pattern of evolution .
Rudimentary 8's could be considered as microdontia but were also separately investigated in order to avoid misleading high prevalence amongst the sample. They occurred in the maxillary wisdom teeth only. No occurrence in the mandible has been observed. The percentage of rudimentary maxillary third molars observed in this study was 2.8%.
Supernumerary teeth were detected in 1.8% of the total sample with more prevalence in males than females. Similar results were reported in the study of the Swiss population which documented a prevalence of 1.5% with higher prevalence in males than females . A higher prevalence (2.8%) was reported in another study of the Egyptian population . On the other hand, a lower prevalence (0.74%) was reported in the Iranian population . Similarly, the Saudi population had a lower incidence of 0.3% with a male-to-female ratio of 1: 2.3 . This is in concert with the range of prevalence of supernumerary teeth 0.1–3.8% reported in other studies , which is also in accordance with our study. Lind  revealed that 3.6% of 1717 Swedish orthodontic patients had supernumerary teeth.
Dilacerations had a similar incidence rate as supernumerary teeth of 1.8% of the total sample with females three times the males. Both dilacerations and supernumerary teeth constituted the least common dental anomalies. This is in correspondence with the study by Thongudomporn and Freer  who also reported them to be the least frequent anomalies. This incidence is higher than the previously reported percentage of 0.4% in the Egyptian population  and much lower than those documented for the Indian population (22.5%) . Some research considered dilaceration a resultant of environmental factors such as trauma ,,. They justified this hypothesis by observing more dilacerations in males than females, due to the higher involvement of males in sports activities. In our study, the higher prevalence of dilaceration in females than males suggests that dilaceration could be an anomaly of developmental origin not correlated with traumatic injuries .
Impacted lower second molars comprised 4.6% of the sample with higher prevalence in the lower arch compared to the upper arch.
There is a high frequency in the scheme of association between different dental anomalies which confirms a genetic relationship. A single genetic defect usually leads to different phenotypic expressions including various combinations such as agenesis, ectopic eruption, microdontia and delayed development . There seems to be a genetic relationship in this study, as an association existed between congenitally missing third molars and other congenitally missing teeth (congenitally missing maxillary lateral incisors). The prevalence of patients who had congenitally missing third molars combined with other missing teeth was 5.3%. A correlation also exists regarding the number of missing wisdom teeth and other congenitally missing teeth. The number of patients who had more than one congenitally missing wisdom tooth and other teeth missing was significantly higher than those who had only one wisdom tooth agenesis accompanied by other congenitally missing teeth. Taking teeth count into consideration, the maxillary left lateral incisor was most commonly associated with agenesis of third molars (2.8%) followed by the upper right lateral incisor (2.3%). The association between different types of dental anomalies has been detected in previous studies, such as microdontia and unilateral agenesis of maxillary lateral incisors occurring in the same patient . Many other interactions between various anomalies were reported in past studies. For example, the anomalies which occurred in association with impacted canines are microdontia, other impacted teeth and transposition ,. In a Chinese study 47.5% of the patients with maxillary canine impaction had other dental anomalies . Some investigators have recommended the use of these associated anomalies as indicators for early diagnosis of canine impaction . This is especially true with congenital absence or microdontia of maxillary lateral incisors which is directly associated with maxillary canine impaction ,. Therefore, early identification of an anomaly has a clinical implication and significance because the early diagnosis of one anomaly can alert the clinician to the possible detection of another one. An association was expected between impacted maxillary permanent cuspids and maxillary third molars probably due to arch length deficiency but that was not true and no correlation was found. In fact, the number of patients who suffered from impacted maxillary cuspids with normally erupted maxillary wisdom teeth were significantly higher (6.4%) than those who had impacted wisdom teeth (2.5%). The cause of impaction is most likely genetic in origin.
| Conclusions|| |
- 63.4% of the sample had at least one dental anomaly.
- Impactions and congenitally missing teeth were the most common dental anomalies (15.2 and 10.1%, respectively).
- Microdontia, supernumerary teeth and root dilacerations are the least frequent observed anomalies (3.4, 1.8, and 1.8%, respectively).
- According to tooth count, the prevalence of second permanent molar impaction was 4.6% with higher occurrence in the lower arch compared to the upper arch.
- Third molar impactions as well as their congenital absence represented a large percentage of the sample (25 and 19.3%).
- Patients with more than one congenitally missing third molar are more likely to have other congenitally missing teeth.
- Generally in most dental anomalies, females were more prone than males with a few exceptions where males were equal or higher than females.
- Wide variation exists in the prevalence of anomalies between various populations and this is mainly due different racial and ethnic backgrounds as well as varying genetic and environmental predilection.
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Conflicts of interest
There are no conflicts of interest.
| References|| |
Garn SM, Lewis AB, Kerewsky RS. X-linked inheritance of tooth size. J Dent Res 1965; 44:439–441.
Kotsomitis N, Dunnu MP, Freer TJ. A genetic aetiology for some common dental anomalies: a pilot twin study. Aust Orthod J 1996; 14:172–178.
Afify AR, Zawawi KH. The prevalence of dental anomalies in the western region of Saudi Arabia. ISRN Dent 2012; 2012:837270.
Garib DG, Peck S, Gomes SC. Increased occurrence of dental anomalies associated with second-premolar agenesis. Angle Orthod 2009; 79:436–441.
Polder BJ, Van't Hof MA, Van Der Linden FP, Kuijpers-Jagtman AM. A meta-analysis of the prevalence of dental agenesis of permanent teeth. Community Dent Oral Epidemiol 2004; 32:217–226.
Altug-Atac AT, Erdem D. Prevalence and distribution of dental anomalies in orthodontic patients. Am J Orthod Dentofacial Orthop 2007; 131:510–514.
Uslu O, Akcam MO, Evirgen S, Cebeci I. Prevalence of dental anomalies in various malocclusions. Am J Orthod Dentofacial Orthop 2009; 135:328–335.
Basdra EK, Kiokpasoglou MN, Komposch G. Congenital tooth anomalies and malocclusions: a genetic link? Eur J Orthod 2001; 23:145–151.
Peck S, Peck L, Kataja M. Thepalatally displaced canine as a dental anomaly of genetic origin. Angle Orthod 1994; 64:249–256.
Baccetti T. A controlled study of associated dental anomalies. Angle Orthod 1998; 68:267–274.
Thilander B, Jakobsson SO. Local factors in impaction of maxillary canines. Acta Odonto Scand 1968; 26:145–168.
Langlais RP, Langland OE, Nortje CJ. Diagnostic imaging of the jaws
ed. Baltimore, MD USA: Williams and Wilkims; 1995. 530–532.
Andreasen JO, Petersen JK, Laskin DM. Textbook and color atlas of tooth impactions: diagnosis, treatment and prevention
. Copenhagen, Denmark, Munksgaard, 1997. 177–195.
Suri L, Gagari E, Vastardis H. Delayed tooth eruption: pathogenesis, diagnosis, and treatment. A literature review. Am J Orthod Dentofacial Orthop 2004; 126:432–445.
Lindauer SJ, Rubenstein LK, Hang WM, Andersen WC, Isaacson RJ. Canine impaction identified early with panoramic radiographs. J Am Dent Assoc 1992; 123:91–95.
Ericson S, Kurol J. Radiographic assessment of maxillary canine eruption in children with clinical signs of eruption disturbance. Eur J Orthod 1986; 8:133–140.
Akarslan ZZ, Kocabay C. Assessment of the associated symptoms, pathologies, positions and angulations of bilateral occurring mandibular third molars: is there any similarity? Oral Surg Oral Med Oral Pathol Oral Radiol 2009; 108:e26–e32.
Garn SM, Lewis AB. The relationship between third molar agenesis and reduction in tooth number. Angle Orthod 1962; 32:14–18.
Mossey PA. The heritability of malocclusion: part 2. The influence of genetics in malocclusion. Br J Orthod 1999; 26:195–203.
Vastardis H. The genetics of human tooth agenesis: new discoveries for understanding dental anomalies. Am J Orthod Dentofacial Orthop 2000; 117:650–656.
Markovic M. Hypodontia in twins. Swed Dent J 1982; 15:153–162.
Thongudomporn U, Freer TJ. Prevalence of dental anomalies in orthodontic patients. Aust Dent J 1998; 43:395–398.
Montasser MA, Taha M. Prevalence and distribution of dental anomalies in orthodontic patients. Orthodontics (Chic) 2012; 13:52–59.
Goncalves-Filho AJ, Moda LB, Oliveira RP, Ribeiro AL, Pinheiro JJ, Alver-Junior SM. Prevalence of dental anomalies on panoramic radiographs in a population of the state of Para, Brazil. Indian J Dent Res 2014; 25:648–652.
Proffit WR, Fields HW. Contemporary orthodontics
. ed 4. St Louis: Mosby; 2007.
Ericson S, Kurol J. Early treatment of palatally erupting maxillary canines by extraction of the primary canines. Eur J Orthod 1988; 10:283–295.
Baccetti T, Leonardi M, Armi P. A randomized clinical study of two interceptive approaches to palatally displaced canines. Eur J Orthod 2008; 30:381–385.
Baccetti T, Mucedero M, Leonardi M, Cozza P. Interceptive treatment of palatal impaction of maxillary canines with rapid maxillary expansion: a randomized clinical trial. Am J Orthod Dentofacial Orthop 2009; 136:657–661.
Bishara SE. Impacted maxillary canines: a review. Am J Orthod Dentofacial Orthop 1992; 10:159–171.
Silva Meza R. Radiographic assessment of congenitally missing teeth in orthodontic patients. Int J Paediatr Dent 2003; 13:112–116.
Diaz-Perez R, Echaverry-Navarrete RA. Agenesis in permanent dentition. Rev Salud Publica (Bogota) 2009; 11:961–969.
Herrera-Atoche JR, Diaz-Morales S, Colome-Ruiz G, Esco e-Ramirez M, Orellana MF. Prevalence of dental anomalies in a Mexican population. Dentistry 3000 2014; 2:1–5.
Aktan AM, Kara S, Akgunlu F, Malkoc S. The incidence of canine transmigration and tooth impaction in a Turkish subpopulation. Eur J Orthod 2010; 32:575–581.
Hou R, Kong L, Ao J, Liu G, Zhou H, Qin R, Hu K. Investigation of impacted permanent teeth except the third molar in Chinese patients through an X-ray study. J Oral Maxillofac Surg 2010; 68:762–767.
Fardi A, Kondylidou-Sidira A, Bachour Z, Parisis N, Tsirlis A. Incidence of impacted and supernumerary teeth – a radiographic study in a North Greek population. Med Oral Patol Oral Cir Bucal 2011; 16:e56–e61.
Roberts-Harry D, Sandy J. Orthodontics. Part 10: impacted teeth. Br Dent J 2004; 27:319–327.
Kramer RC, Williams AC. The incidence of impacted teeth. A survey at Harlem Hospital. Oral Surg Oral Med Oral Pathol Oral Radiol 1970; 29:237–241.
Yavuz MS, Aras MH, Buyukkurt MC, Tozoglu S. Impacted mandibular canines. J Contemp Dent Pract 2007; 8:078–085.
Celikoglu M, Kamak H, Oktay H. Investigation of transmigrated and impacted maxillary and mandibular canine teeth in an orthodontic patient population. J Oral Maxillofac Surg 2010; 68:1001–1006.
Rózsa N, Nagy K, Vajó Z, Gabris S, Soos A, Alberth M, Tarjan I. Prevalence and distribution of permanent canine agenesis in dental paediatric and orthodontic patients in Hungary. Eur J Orthod 2009; 31:374–379.
Endo T, Ozoe R, Kubota M, Akiyama M, Shimooka S. A survey of hypodontia in Japanese orthodontic patients. Am J Orthod Dentofacial Orthop 2006; 129:29–35.
Nordgarden H, Jensen JL, Storhaug K. Reported prevalence of congenitally missing teeth in two Norwegian counties. Community Dent Health 2002; 19:258–261.
Silverman NE, Ackerman JL. Oligodontia: a study of its prevalence and variation in 4032 children. J Dent Child 1979; 46:470–477.
Horowitz JM. Aplasia and malocclusion: a survey and appraisal. Am J Orthod Dentofacial Orthop 1966; 52:440–453.
Rose JS. A survey of congenitally missing teeth, excluding third molars, in 6000 orthodontic patients. Dent Pract 1996; 17:107–114.
Grahnén H. Hypodontia in the permanent dentition. A clinical and genetical investigation. Odont Rev 1956; 7:95–100.
Al-Emran S. Prevalence of hypodontia and developmental malformation of permanent teeth in Saudi Arabian school children. Br J Orthod 1990; 17:115–118.
Clayton JM. Congenital dental anomalies occurring in 3557 children. J Dent Child 1956; 23:206–208.
Kazanci F, Celikoglu M, Miloglu O, Oktay H. Third-molar agenesis among patients from the East Anatolian Region of Turkey. J Contemp Dent Pract 2010; 11:e033–e040.
Guttal KS, Naikmasur VG, Bhargava P, Bathi RJ. Frequency of developmental dental anomalies in the Indian population. Eur J Dent 2010; 4:263–269.
Schmuckli R, Lipowsky C, Peltomäki T. Prevalence and morphology of supernumerary teeth in the population of a Swiss community. Schweiz Monatsschr Zahnmed 2010; 120:987–990.
Vahid-Dastjerdi E, Borzabadi-Farahani A, Mahdian M, Amini N. Supernumerary teeth amongst Iranian orthodontic patients. A retrospective radiographic and clinical survey. Acta Odontol Scand 2011; 69:125–128.
Luten JR Jr The prevalence of supernumerary teeth in primary and mixed dentitions. J Dent Child 1967; 34:346–353.
Backman B, Wahlin YB. Variations in number and morphology of permanent teeth in 7-year-old Swedish children. Int J Paediatr Dent 2001; 11:11–17.
Lind V. Medfodda antalsvariationer I permanenta dentitionen. Odont Rev 1959; 10:176–189.
Welbury RR, Duggal MS, Hosey MT Pediatric dentistry
. ed 3. Oxford: Oxford University Press; 2005. 266–268.
Hamasha AA, Al-Khateeb T, Darwazeh A. Prevalence of dilaceration in Jordanian adults. Int Endod J 2002; 35:910–912.
Mercuri E, Cassetta M, Cavallini C, Vicari D, Leonardi R, Barbato E. Dental anomalies and clinical features in patients with maxillary canine impaction: a retrospective study. Angle Orthod 2013; 83:22–28.
Sajnani AK, King NM. Dental anomalies associated with buccally and palatally-impacted maxillary canines. J Investig Clin Dent 2014; 5:208–213.
Becker A, Smith P, Behar R. The incidence of anomalous maxillary lateral incisors in relation to palatally-displaced cuspids. Angle Orthod 1981; 51:24–29.
Kurol J. Impacted and ankylosed teeth: why, when, and how to intervene. Am J Orthod Dentofacial Orthop 2006; 129:S86–S90.
[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8], [Table 9], [Table 10], [Table 11], [Table 12]