| Abstract|| |
Introduction: Dental anomalies (DAs) are the result of disorders that are able to modify the shape, number, size, and structure of teeth. This study aimed to evaluate the prevalence of DAs using panoramic radiographs in a population of the City of Belém, northern Brazil.
Materials and Methods: In this study, 487 panoramic radiographs were evaluated searching for DAs. Dental records were reviewed for diagnostic confirmation. DAs related to the shape, number, size, and structure of teeth were investigated.
Results: Our results showed a DA prevalence of 56.9%. The most prevalent DA was taurodontism, which was present in 27.19% of cases. Root dilaceration was the second most prevalent DA in adults, whereas hypodontia was the second most prevalent DA in children. A total of 13 DAs were found.
Conclusions: Dental anomalies were present in over half of the sample, and most of them were related to the shape of the teeth. Although there was a high prevalence of shape-related DAs, these alterations are generally of lower severity, and most do not require specific treatment. However, in 19.25% of cases, DAs were found involving the number, size and structure of the teeth. These DAs should be diagnosed and treated early, avoiding thus more serious complications.
Keywords: Dental anomalies, dental disorders, oral pathology, taurodontism
|How to cite this article:|
Goncalves.Filho AJ, Moda LB, Oliveira RP, Ribeiro AR, Pinheiro JJ, Alver-Junior SM. Prevalence of dental anomalies on panoramic radiographs in a population of the state of Pará, Brazil
. Indian J Dent Res 2014;25:648-52
Dental anomalies (DAs) typically occur as a result of disturbances during tooth development and can change the shape, number, size and structure of tooth and patterns of tooth eruption.  Changes in the pattern of tooth eruption, can affect the organization of the dental arches and cause malocclusion. All of them may modify the surgical treatment, endodontics, and restorative dental procedures.  Thus, the identification of DAs and their prevalence can be of great help in preventing surgical accidents, improving dental occlusion, and also can guide a more effective dental treatment.
|How to cite this URL:|
Goncalves.Filho AJ, Moda LB, Oliveira RP, Ribeiro AR, Pinheiro JJ, Alver-Junior SM. Prevalence of dental anomalies on panoramic radiographs in a population of the state of Pará, Brazil
. Indian J Dent Res [serial online] 2014 [cited 2019 Jul 17];25:648-52. Available from: http://www.ijdr.in/text.asp?2014/25/5/648/147115
Dental anomalies can arise from changes in the three mineralized components of the tooth: The enamel, the dentin and the cementum.  These changes can arise during malformation of the dental matrix, mineralization or dental maturation, and also can occur during one of the three basic phases of the structural formation of human dentition: Genetic, intrauterine, and postnatal phases. 
The prevalence of DAs is variable, depending on the type of anomaly and the studied population. They can occur in both primary and permanent dentitions. Although anomalies of the permanent dentition are considered to be the most significant by their long-term commitment, anomalies in the primary dentition can also cause important temporary complications and even future complications for the permanent dentition. 
Individual studies of DAs have led to advances in knowledge of the prevalence of these alterations, although these studies also demonstrate important differences according to the studied population. Hence, these results indicate that there is no global standard of DAs, reinforcing the role played by genetics and environmental influences in the etiology of these disorders. 
In summary, the occurrence of DAs can interfere negatively with dental treatment, and they are influenced by environmental and genetic factors. Based on these findings, this study aimed to evaluate the prevalence of DAs using panoramic radiographs of adult and child patients in the city of Belém, northern Brazil.
| Materials and methods|| |
This was a retrospective study based on the analysis of 503 randomly selected panoramic radiographs of patients who attended the dental clinic of the school of dentistry of the University Center of Parα between 2003 and 2012. This clinic is a reference center in dental care for the population of the city of Belém and Parα State. This state has a mixed population that is 73% brown, 23% white, 3.4% black, and 0.6% indigenous.  This study was approved by the committee of ethics in research of the University Center of Parα beneath the protocol number 129.215-2012.
Panoramic radiographs and dental records of 503 patients were analyzed together to collect data for diagnostics and to confirm radiographic alterations that were found. The exclusion criteria used included incomplete filling of the dental records, poor quality of the panoramic radiograph precluding its correct evaluation, patients in whom radiographs were contraindicated due to pregnancy, and also patients with any syndrome. Using these criteria, 25 were eliminated, leaving a total of 478 radiographs included in the study.
All panoramic radiographs were performed using the same equipment GendexOrthoralix S (Gendex, Hatfield, Pennsylvania, USA). The radiographs were processed in a darkroom and the development process was carried out in 90 s, followed by a wash in the tank with running water, fixation for 5 min and a final wash in running water for 10 min. After the final wash, the radiographs were dried at room temperature.
The radiographs selected were divided into two groups by age. Group I was named "children" and consisted of individuals between 1 and 12 years of age. Group II was named "adults" and consisted of teenagers and adults. Radiographs were analyzed with the aid of a negatoscope and a magnifying glass. Radiological analyses were conducted by the same radiologist, who was limited to analyzing 30 radiographs/day with a minimum interval of 24 h between sessions.
Four categories of DAs were analyzed:
- Shape abnormalities: Taurodontism; root dilaceration; peg-shaped tooth; talon cusp; shell tooth; dens in dente and concrescence
- Number abnormalities: Hypodontia and hyperdontia
- Size abnormalities: Microdontia and macrodontia
- Structural abnormalities: Amelogenesis imperfecta and enamel hypoplasia.
Data related to differences between Groups I and II were analyzed using the Graph Pad Prism 5 software (Graph Pad Software Inc., San Diego, CA, USA). Statistical differences were analyzed using the binomial test comparing two proportions and Fisher's exact test.
| Results|| |
Dental anomalies were present in 56.9% of the sample and were more prevalent in Group I, 72.22%, than in Group II, 49.05%, [Table 1]. The most common dental anomaly was taurodontism (27.19%), followed by root dilaceration (14.01%); both are related to the alteration of the shape of the tooth, which represented 71.07% of the anomalies found [Table 2]. The second most prevalent category of DAs was numerical alterations, followed by alterations of form and structure [Table 2].
|Table 1: Presence of dental anomalies on 478 panoramic radiographs in a population of the state of Pará, Brazil |
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|Table 2: Prevalence by type of dental anomalies on 478 panoramic radiographs in a population of the state of Pará, Brazil |
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When analyzed individually, Group I presented a high prevalence of taurodontism (38.26%). This group also presented a higher prevalence of hypodontia and hyperdontia relative to Group II [Table 2].
Group II demonstrated a higher prevalence of root dilaceration than Group I; this prevalence was slightly lower than that of taurodontism. Group II had a higher prevalence of microdontia than Group I; microdontia was the third most common anomaly in adult patients. [Table 2] summarizes our main results.
| Discussion|| |
Identification of DAs in a specific population is important because it allows to identify in a precocious manner the most common disorders of this population, and thus, favors an early diagnosis and proper management. Studies related to the prevalence of DAs often present discrepant results, which may be due to ethnic differences and sampling differences. ,, Our results showed that DAs were present in 56.9% of the cases [Table 1]; anomalies in the shape of teeth were the most common (47.28%), followed by alterations of number (12.13%), size (6.06%) and structure (1.05%) [Table 2].
The most prevalent DAs was taurodontism, regardless of the age group or gender. Taurodontism was present in 27.19% of the cases [Table 2], which was higher than that found in Jordanian (8%)  and Indians (18%).  This result is quite high relative to the averages found in the American population (2.5-4.37%).  This difference can be explained by the fact that one of the possible causes of taurodontism is the invagination failure of Hertwig's epithelial sheath, which is genetically determined. 
Root dilaceration was the second most prevalent anomaly found and it was present in 14.01% of the cases [Table 2]. This prevalence is higher than those found in the majority of previously reported studies, which vary from 1% to 5.5%, respectively.  Root dilaceration is an abnormal curvature in the tooth between the crown and the root and usually occurs as a result of a trauma. , It can cause a substantial limitation in orthodontic treatment and also requires tooth removal in more severe cases.  Root dilaceration can complicate tooth extraction and should be carefully analyzed in surgical planning. 
Peg-shaped tooth refers to a tooth that has a conical shape with a sharp and acute edge, typically located in the region of the upper incisors. , Peg-shaped tooth are rare in both dentitions,  but we found that it was the third most prevalent anomaly in tooth shape in the studied population (2.09%). In Group I, its prevalence was 4.94% [Table 2], which makes our findings higher than those of another study that found the prevalence of peg-shaped teeth to be 0.8% in children;  all of those cases were located in the upper lateral incisors.
Other anomalies were also present with a lower prevalence. A talon cusp or accessory cusp is an alteration of the tooth shape that is characterized by the presence of an accessory cusp on the lingual or buccal face of an anterior tooth. Studies reporting the prevalence of talon cusps are limited, but estimates suggest that its incidence is between 1% and 8% of the population.  Our results showed an occurrence of 1.67% [Table 2], which is within this expected range of incidence but close to the lower limit. This anomaly was more commonly found in male children. The lack of studies on talon cusp may be because it does not require any treatment, except when it interferes with the dental occlusion. In this case talon cusp should be removed. 
Dens in dente, also called dens invaginatus, is an embryonic anomaly that occurs as a result of the invagination of cells of the internal enamel epithelium.  As a result of invagination, the dental walls have locations that are thin and close to the pulp tissue,  which may causes pulp necrosis.  Dens in dente presents a variable prevalence from 0.25% to 7.74%, , but its prevalence is generally low, as was observed in this study (0.63%) [Table 2].
The union of the roots of two or more teeth through the cementum is called concrescence. , Patients presenting concrescence require no treatment unless this union interferes with the dental eruption; in which case, surgical removal of the teeth must be performed.  The prevalence of concrescence found here was 0.63% [Table 2], and all cases were found in female patients.
Abnormalities of number were the second most common DA and they are related to the presence of an extra tooth (hyperdontia) or absence (hypodontia) of one or more teeth in the dental arch.  Hypodontia is the condition in which a tooth is congenitally absent in the dental arch, and its presence is not visible neither clinically nor radiographically, meaning that there was no formation or development of its germ. ,
Hypodontia is one of the most common DAs, and the absence of one permanent tooth can cause serious damage to bone development and function; it can also compromise facial aesthetics. , Hypodontia more frequently affects the permanent teeth than the primary teeth,  with a reported prevalence of hypodontia of permanent teeth varying from 2.6% to 11.3%, respectively.  We found thirty cases of hypodontia (6.28%) with a higher prevalence in Group I [Table 2]. Studies show that there is a prevalence of hypodontia in females, , that was confirmed by our results with a ratio of 1.73:1.
Hyperdontia is characterized by the formation of an extra tooth in the dental arch; the additional tooth is called supernumerary tooth.  Hyperdontia can negatively influence dental occlusion,  hinder the eruption of permanent teeth, and limit orthodontic treatments. In most cases, supernumerary teeth require surgical removal.  In this study, 28 individuals (5.86%) presented with at least one supernumerary tooth [Table 2]; this is a high prevalence compared with previous studies, which found a prevalence ranging from 0.33%  to 1.8%. 
Alterations in the size of tooth include microdontia and macrodontia.  These Das involve changes to the length of the dental arch at the alveolar bone, causing alterations in the occlusion with the antagonist arch. ,, Therefore, microdontia and macrodontia can generate malocclusion by diastema and crowding, respectively. , In most cases, when a person presents microdontia or macrodontia, another family member also present this anomaly. 
Microdontia was present in 5.44% of the cases. Our results are intermediate between a study that observed a higher prevalence of microdontia 9.14% [Table 2];  and others that observed a smaller prevalence vary from 0.1%  to 1.58%.  We observed a higher prevalence of microdontia in Group II (6.96%), this prevalence is also higher than the majority of studies that show a prevalence lower than 0.55%. 
In contrast, macrodontia had a low prevalence (0.63%) [Table 2]. This result is much lower than the prevalence of microdontia (5.44%), which is in agreement with other authors who assert the rarity of macrodontia.  Macrodontia is an uncommon condition and generally affects >1% of the population. ,
Abnormalities of tooth structure are very rare and as such, were found only in 1.05% of the sample [Table 2]. Two anomalies of tooth structure were studied, amelogenesis imperfecta and enamel hypoplasia. Amelogenesis imperfecta can be characterized as a hereditary alteration of tooth development that occurs due to changes in the quality or quantity of the enamel.  Clinical alterations of amelogenesis imperfecta included aesthetic defects, dentinal sensitivity, gingivitis, dental cavities, and loss of mechanical properties of the tooth. Amelogenesis imperfecta is considered rare;  however, a slightly higher prevalence was found in this study (0.63%) compared with data from an Indian (0.27%)  and a Turkish population (0.43%). 
Enamel hypoplasia is a quantitative alteration of the structure of the tooth enamel, whose etiology is related to genetic and environmental factors. , Only two cases were found in this study. This reduced prevalence may be a consequence of milder manifestations, in which some cases were not diagnosed.
Studies about prevalence of a particular disease in a given population are of great importance, especially when the disease being studied is directly influenced by genetic and environmental factors as DAs. Our sample received strong influence from indigenous people of the Amazon region, and also from immigrants from Portugal, Spain, Germany, and also from black African countries. As a result, the majority of the population (73%) is brown,  reflecting an intense racial miscegenation. Hence, the genetic and environmental influences of these immigrants are particular, and therefore, the results presented here are unique.
| Conclusions|| |
Our study demonstrated that there was a prevalence of DAs of 56.9% in the population studied, and the most common alterations were those related to the shape of the teeth (47.28%). These shape anomalies tend to cause less dental impairment in comparison to other alterations, and many of these do not require specific treatment. Taurodontism was the most common dental alteration, followed by root dilaceration, which occurred mainly in adults. Alterations of number, size and structure (in decreasing order) occurred in 19.25% of cases. These anomalies are related to dental problems with greater clinical impact; consequently, the order of their prevalence and the problems resulting from these alterations should be known by dentists, investigated, diagnosed and treated early to avoid more serious complications.
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Andre Luis Ribeiro Ribeiro
Departments of Oral and Maxillofacial Surgery, School of Dentistry, University Center of Pará
Source of Support: None, Conflict of Interest: None
[Table 1], [Table 2]