Keywords

Prevalence, Supernumerary, Teeth, Hospital, Gombe.

Introduction

Supernumerary teeth are defined as any extra tooth formed in normal dentition and this condition is also called “hyperdontia.” The prevalence of supernumerary teeth for permanent dentition is between 0.5% and 5.3% and in primary dentition is between 0.2% and 0.8% in various populations [1-5]. Also, the gender-wise prevalence of supernumerary teeth or hyperdontia shows that these teeth are predominantly seen in males than in females [5-8]. Supernumerary teeth may be associated with several syndromes such as cleidocranial dysplasia, Gardner’s syndrome, Ehlers-Danlos syndrome, and Fabry-Anderson syndrome [2,5-6]. In these cases, supernumerary teeth often appear in multiple forms. However, these teeth may occur in patients with no syndrome and may appear as single, double, or multiple and as unilateral or bilateral [2,5,9,10].

Although the main etiology of supernumerary teeth is not certainly explained, several theories have been proposed and the most common view is that these teeth develop as a result of horizontal proliferation or hyperactivity of the dental lamina [2,5,10,11]. Supernumerary teeth may be located in any region of the dental arch; however, they are usually found on the maxillary midline between two maxillary central teeth, and these teeth are called mesiodens. This is commonly followed by maxillary molar, maxillary lateral incisor, mandibular premolar, and mandibular molar. Supernumerary teeth may be classified morphologically according to their shape as conical, tuberculate, supplemental, and odontomatous [5,11,12].

Supernumerary teeth may erupt normally or may be impacted, and they may cause some complications such as failure of eruption, displacement, crowding, diastemas, development of odontogenic cyst, and resorption of neighboring teeth [5,11,12]. Radiological examinations have been used for locating the position of the supernumerary tooth. Treatment options change according to the severity of the complication. Thus, the treatment options include clinical follow-up for a particular period, surgical removal, and orthodontic [5,11-14].

The presence of supernumerary teeth results in different well-known complications such as un-eruption or delayed eruption, ectopic eruption, displacement, diastemas, occlusal problems, rotated neighboring teeth, radicular resorption, and cyst formation [12,15-18]. But in some cases, supernumerary teeth are asymptomatic and they cannot be diagnosed without routine radiographic examination if they do not appear in the oral and maxillofacial region.

Many studies showed that the prevalence of supernumerary teeth was diversely reported and varies according to race, ethnicity, and geographic situation. To the best of my knowledge, no study has been carried out to assess the prevalence and occurrence of supernumerary teeth in this region.

The aim of the present study is to evaluate the prevalence of supernumerary teeth among people living in Gombe State Nigeria.

Materials and Methods

Sampling

The total number of 300 children and adults, consisting of an equal number of males (n=150) and females (n=150) that are attending dental clinic specialist hospital Gombe for different reasons such as tooth extraction, dental caries, malocclusion, delay, or lack of the eruption of permanent teeth, trauma of maxillofacial region and a routine dental check-up. The ages range from 5 years to 76 years were randomly selected for this research, after been informed about the research.

The procedure of data collection

Initially, the basic information which includes: Age, Gender, Address, and Date of birth was recorded. The dental examination was then carried out with the subject seated on an ordinary chair, under natural light and using a mouth mirror, hand gloves, and a blunt probe. The teeth were cleaned of food debris with cotton wool for proper visibility.

All supernumerary teeth were classified under several titles such as location (maxilla or mandible, specifying the region from anterior to posterior), position (vertical, angled, horizontal, or inverted), morphology (conical, tuberculated, supplemental, and odontoma), and eruption (unerupted or erupted). Clinical complications and treatment protocols were analyzed.

Data analysis

The data obtained were subjected to a Chi-square test was to determine differences in the distribution of supernumerary teeth. The data analysis was carried out using SPSS version 18.0 software. The statistical significance was established by a confidence interval of 95% (p ≤ 0.05).

Results

The total number of patients used for this study were 300 patients that have supernumerary teeth, among which 150 were males (50%) and 150 were females (50%), with an age range of 5-76 years and a mean age of 18 (SD ± 4) years. Out of which 346 supernumeraries were discovered. 171 (49.6%) were discovered from males and 175 (50.4%) were from females in Table 1.

Table 1: Distribution of patients and supernumerary teeth according to gender.

The prevalence of supernumerary teeth was 5.2% among which the incisor was the most prevalent supernumerary teeth with 3.39% (n=194), followed by premolars (0.75%; n=43), canines (0.46%; n=27) and by molars (0.42%; n=24). The deciduous teeth were noted by (0.20%; n=12) Table 2.

Table 2:Distribution of patients according to the type of impacted teeth and the prevalence of supernumerary teeth.

Table 3 shows that the frequency of supernumerary teeth was more in maxillar (89.9%; n=311) than mandible (10.1%; n=35) and more in female (50.6%; n=175) than male (49.4%; n=171). The precisely higher prevalence of supernumerary teeth in the female gender was statistically significant (p=0.03). A significant difference was also found between the localization of supernumerary teeth in the maxilla and mandible (p=0.01).

Table 3: Distribution of supernumerary teeth according to gender and localization.

Table 4 shows that the Supernumerary teeth mostly occurred in children between 5-10 years (61.4%; n=212), followed by the young adolescent population between 11-16 years (25.6%; n=88).

Table 4: Distribution of Supernumerary teeth according to age group.

Table 5 shows the orientation of supernumerary teeth, in which 65.7% (n=227) are vertically oriented, 18.3% (n=63) are angular oriented, 8.6% (n=30) are transverse oriented and 7.4% (n=26) are inverted.

Table 5: Distribution of Supernumerary teeth according to orientation.

Table 6 shows the number of supernumerary teeth in each patient, in which 86.3% 9 (n=259) of the patients were observed with one supernumerary tooth, 12.3% (n=37) of the patients were observed with two supernumerary teeth and 1.3% (n=4) of the patients were observed with three or more supernumerary teeth.

Table 6: Distribution of Supernumerary teeth according to number.

Table 7 shows the state of supernumerary eruption within the arch, in which 124 of the supernumerary teeth (35.8%) had erupted and 222 supernumerary teeth (64.2%) were impacted.

Table 7: Distribution of Supernumerary teeth according to the state of eruption.

Table 8 shows the supernumerary teeth complications, in which 211 (61.1%) did not cause any complication, while 108 teeth (31.1%) caused impaction and 27 teeth (7.8%) caused the displacement of the adjacent teeth.

Table 8: Distribution of Supernumerary teeth according to complications.

Discussion

The prevalence of supernumerary teeth was reported to be different among different racial and ethnic groups. The prevalence was between 1%-3% in the Caucasian population, greater than 3% in Asians, and between 0.42% to 5.6% in Africa [19,20]

This study discovered the prevalence of supernumerary teeth in the Gombe state population was 5.2% in which the incisor presented 3.39%. This higher rate of prevalence can be explained by the fact that the variations due to differences in demographic and environmental factors and different sample size susceptibilities that may have an impact on the reported prevalence rate. Those studies which found this variation of prevalence are not close to our study. This difference can also be explained by the fact that the included population in those studies was only the children and young population but the recent study included all patients of the different ages from 5 to 76 years old and hence maybe justify this increased prevalence rate.

In the literature to date, the incidence of supernumerary teeth is usually higher in males than in females and the reported male to female ratio was between 1.18:1 to 4.5:1 which is not similar to the present study that showed male to female ratio as 1:1. It is also reported correspondingly by other studies in Caucasians [21,22]. Hence, our research also shows that the proportion of supernumerary teeth concerning sex was also more prevalent in the female population (P<0.001). The ratio between males and females was found diverged than our study in some literature, such as the study of Liu et al. [23] in China with 2.64:1 (male/female), a study of Esenlik et al. [13] in turkey (1.13:1), a study of Rajab and Hamdan [10] (2.2:1) and in a study made by Çelikoğlu [20] who had noted 1.8:1 ratio male to female respectively. Also, the male to female ratio was 6.5:1 in the different studies of Chinese children [24]. The results of this research showing variables frequencies in sex ratio may be due to racial differences or possible sampling differences which also showed the variation of sex ratios in China. This situation can also be explained by the fact that there are differences between the age range, the number of examined patients, the limited number of the affected subjects, and the methods used in these studies.

In the data from the literature the age of patients with supernumerary teeth ranges from 5 to 76 years, but the supernumerary teeth were mostly observed between the age group of 7 and 10 [10,25]. Esenlik et al. [13] reported in his research most cases were found between the age of 7-9. This affirmation is similar to our result, which reported that most supernumerary teeth were found in the age group between 5-10 years (61.4%; n=212), followed by the age group between 11-16 years (25.6%; n=88). Even though the prevalence of supernumerary teeth was seen highest among the age group of 5-10 years and 11 to 16 years, it was seen decreasing with increasing age and independent of gender.

Many studies have identified that the most commonly involved location of supernumerary teeth is the premaxilla [13,25]. In our present study, the premaxillary regions were the predominant location of supernumerary teeth and 50.9% of these teeth were mesiodens which is similar to the study reported by Montenegro et al. and Bäckman and Wahlin [26,27]. This situation may be explained by obvious complications of mesiodens which makes it easily diagnosed by the parents and this affects the number of referrals.

Regarding the location of observed supernumerary teeth in this research, 90% (n=311) of the supernumerary teeth were found in the maxillary arch. These results were similar to the data reported by De Oliveira et al. who found that 91.3% of the supernumerary teeth were found in the maxillary arch [11].

Our results are also agreed to the studies of Hattab et al. [28] and Zhu et al. [29] that showed that 90% of supernumerary teeth were found in the maxillary bone and this supports our conclusions. The incisor (56.8%; n=197) were the most commonly appearing supernumerary teeth in which the central incisor (45.3%; n=157) being the most common among them, likewise reported by Hyun et al. [30] and Dermiriz et al. [5]. The recent study noted an occurrence of supernumerary teeth in the deciduous dentition by a prevalence of 4.6% and all in maxilla analogous to others authors who had shown that the prevalence of supernumerary teeth ranges from 0.2% to 0.8% in the deciduous dentition [10,31]

From the literature data, supernumerary teeth may occur in either single or multiples numbers in any region of the jaws of the same person. It is well-known that supernumerary teeth are more frequently single, while multiple supernumerary teeth are normally two in number [10,11,20].

However, multiple supernumerary teeth co-exist rarely without any diseases or syndromes. According to our results, 74.9% (n=259) of the supernumerary teeth were single, 21.7% (n=75) were double and 3.4% (n=12) were multiples supernumerary teeth. Our findings coincide with the ones given in the literature data.

About the eruption status, we found out that 35.8% (n=124) of the supernumerary teeth erupted. Our results were close to other studies which reported about erupted supernumerary teeth [5,10,13,25]. All erupted supernumerary teeth were normally orientated while none of the transverse or inverted supernumerary teeth erupted. So, we verified that erupted supernumerary teeth were commonly vertical 65.7% (n=227). The detection of supernumerary teeth is very necessary but early diagnosis helps to prevent or minimize possible complications [10,32]. Clinical complications were seen in 38.9% of the supernumerary teeth. Displacement and impaction were the most frequent complication which is also reported by many authors [13,33].

Conclusion

The prevalence of supernumerary teeth in the Gombe region was higher and its frequency was mostly in children between 5 years to 10 years followed the young adolescent population between 11 years to 16 years old. It was more frequent in the maxillary region and around the incisor of the permanent dentition, in which most of them have singly erupted and asymptomatic, although some of them are accompanied by some symptoms like impaction, crowding, and displacement.

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