Epidemiological, Clinical and Radiographic Features of Supernumerary Teeth in Nonsyndromic Bosnian and Herzegovinian Population: a Monocentric Study

Abstract

Background:

Supernumerary teeth (ST) represent one of the most common developmental anomalies among humans.

Objective:

In this study, we set a goal to investigate ST prevalence in the Bosnian and Herzegovinian population along with characteristics and complications that ST can cause.

Methods:

This retrospective study was based on panoramic radiographs, CBCT images, and dental records. Analyzed ST characteristics were: type, morphology, location, eruption state, location in the arch, orientation, and associated clinical complications. Statistical analysis included univariate analysis and bivariate analysis using Fisher’s exact test with a confidence interval of 95% (p<0.05).

Results:

On a sample of 10.237 patients, ST teeth appear in 100 patients with a prevalence of 0.98%. Out of 138 analyzed ST mesiodens was the most frequent (43.47%). The most common location of the ST was maxilla (77.53%). The majority of ST were impacted (90.5%) but with no complications (71.7%). There was statistically significant relationship (p<0.001) between the type of ST and location (mesiodens and distomolars were mostly found in the maxilla). The relationship between ST type and morphology was also statistically significant (p<0.001)–mesiodens was associated with conical morphology, parapremolar with supplementary, and distomolar with tuberculate morphology. The occurrence of ST-associated retention of adjacent teeth was correlated to the type of tooth (p<0.001)

Conclusion:

The present study found prevalence of ST in B&H population to be low. Although associated pathology was not high early diagnosis allows optimal patient management which reduces later complications.

1. BACKGROUND

As one of the most common developmental anomalies among humans, supernumerary teeth (ST) represent teeth or odontogenic structures that exceed 20 primary teeth and 32 permanent teeth (1-3). ST can rarely exist within the regular dental formula in cases of concomitant hypo-hyperdontia (4, 5).The presence of ST is a condition known as hyperdontia or hypergenesis and its prevalence varies from 0.2 to 0.8% in primary dentition and from 1.5 to 3.8% in permanent dentition (6-8). This number can go up to 28% in patients with congenital anomalies (9). The prevalence of ST in permanent dentition is affected by ethnicity, race, gender, and varying study protocols (3, 7, 10, 11). The etiology of hyperdontia is yet to be clarified. Several hypotheses have tried to explain ST’s origin, including atavism, the dichotomy of the tooth germ, hyperactivity of dental lamina, and environmental factors (12). Most supernumerary teeth do not cause any complications, but ST may cause cyst formation, delayed eruption, malposition, root resorption of the adjacent tooth, etc. (13). This study’s goal was to determine the prevalence of ST in the population of Bosnia and Herzegovina’s (BH) in what we believe is the most comprehensive study of ST in the BH population. Along with the prevalence, we wanted to see characteristics and complications of ST in the group studied and compare it with the results of similar studies worldwide.

2. OBJECTIVE

In this study, we set a goal to investigate ST prevalence in the Bosnian and Herzegovinian population along with characteristics and complications that ST can cause.

3. MATERIAL AND METHODS

This descriptive, retrospective, monocentric study investigated records of patients seeking dental treatment between January 2013 and March 2020 at the University of Sarajevo’s Faculty of Dental Medicine with Clinics. The study was conducted with the approval of the Institution’s Ethics Committee (No. 02-3-4-59-1-10/2020). The study’s material consisted of panoramic radiographs, CBCT images, and dental records of 10.237 patients.

Patients with cleft lip or palate, cleidocranial dysostosis, Gardner syndrome, and other craniofacial anomalies or genetic syndromes generally associated with supernumerary teeth were excluded (14).

The study sample was made up of patients that presented with supernumerary teeth. Other cases were dismissed.

Following data were recorded for each patient: medical record number, age, sex, type of each supernumerary tooth: mesiodens, supernumerary lateral incisive, supernumerary canine, parapremolar, paramolar, distomolar; morphology of ST: conical, tuberculate, supplemental; location of ST: maxilla or mandible; eruption state: impacted or erupted; location in the arch: oral, vestibular, and aligned in the arch; orientation: vertical, inclined, horizontal and inverse position; associated clinical complications: retention/impaction of permanent tooth (PT), change of position/shape of PT, diastema, enlargement of follicular space, resorption of the adjacent tooth.

The same researcher analyzed the radiographs; any dilemma was resolved by discussion among the team members of the research project until reaching a consensus.

All data were recorded on an MS-Excel spreadsheet and further analyzed using SPSS version 25.0 for Windows statistical package. Statistical analysis included univariate analysis (mean, median, etc.) and bivariate analysis using Fisher’s exact test, whereby statistical significance was established with a confidence interval of 95% (p<0.05).

4. RESULTS

4.1. Univariate analysis

The majority of the case (87%) was analyzed using a panoramic radiograph, and only 13% of the sample was evaluated using CBCT images.

Supernumerary teeth were found in 100 patients, representing a prevalence of 0.98% of the total study population. Out of the 100 patients, 46 were women (46%) and 54 (54%) men, with a male/female ratio of 1/1.17. The patients studied’ mean age was 17.5, with 45% of patients under 18 (Table 1).

Table 1. Descriptive epidemiological data for 100 patients with ST.

Variable		Number(%)
Age	<18	45 (45%)
	18-30	45 (45%)
	> 60	1 (1%)
Sex	Male	54 (54%)
	Female	46 (46%)
Number of ST	Single	75 (75%)
	Multiple	25 (25%)
Arch	Maxilla	81(81%)
	Mandible	13 (13%)
	Both (maxilla and mandible)	6 (6%)
Side	Right side	25 (25%)
	Left side Both (right side and left side) Midline	30 (30%) 18 (18%) 27 (27%)

A total of 138 ST were found in the studied sample with the following distribution: 75% of patients presented a single ST, 25% showed more than one ST (Figure 1). Most of them (90.5%) were impacted (Table 1).

Figure 1. Representative radiographic images exhibiting diverse numbers of ST. (a) Single ST; (B) Two ST; (c) Three ST; (d) Four ST; (e) Seven ST.

Mesiodens (43.47%) was the most frequent ST, followed by distomolar (28.98%), parapremolar (21.74%), supernumerary lateral incisor (2.9%), paramolar (1.45%) and supernumerary canine (1.45%) (Figure 2). Most of the ST were found in the maxilla (77.53%), while 22.47% of ST were found in the mandible. The most common ST found in the maxilla was mesiodens (55.1%), followed by distomolar (31.8%), whereas parapremolar was the most frequent ST found in the mandible (71%). Most of the ST were vertically oriented (67.39%) (Table 2).

Figure 2. Representative OPG and CBCT images of different types of ST. (a) Paramolar; (b) Supernumerary canine; (c) Mesiodens; (d) Supernumerary lateral incisor; (e) Parapremolar; (f) Distomolar .

Table 2. Descriptive data regarding location, morphology, orientation, and eruption status of 138 supernumerary teeth.

		Mesiodens	SN lateral incisor	SN canine	Parapremolar	Paramolar	Distomolar	P
Number	138	60 (43.4%)	4 (2.9%)	2 (1.45%)	30 (21.74%)	2 (1.45%)	40 (29.98%)
Arch	<0.001
Maxilla	107 (77.53%)	59 (55.1%)	4 (3.7%)	1 (0.9%)	8 (7.5%)	1 (0.9%)	34 (31.8%)
Mandible	31 (22.46%)	1 (3.2%)	0	1 (3.2%)	22 (71%)	1 (3.2%)	6 (19.4%)
Morphology	<0.001
Conical	47 (34.05%)	39 (83%)	0	0	2 (4.3%)	0	6 (12.8%)
Supplementary	50 (36.23%)	18 (36%)	4 (8%)	2 (4%)	25 (50%)	0	1 (2%)
Tuberculate	41 (29.71%)	3 (7.3%)	0	0	3 (7.3%)	2 (4.9%)	33 (80.5%)
Position in the arch	<0.001
Oral	98 (71.01%)	52 (53.1%)	0	2 (2%)	24 (24.5%)	2 (2%)	18 (18.4%)
Vestibular	6 (4.34%)	4 (66.7%)	0	0	2 (33.3%)	0	0
In line	34 (24.63%)	4 (11.8%)	4 (11.8%)	0	4 (11.8%)	0	22 (64.7%)
Orientation	<0.05
Horizontal	8 (5.79%)	3 (37.5%)	0	0	1 (12.5%)	0	4 (50%)
Vertical	93 (67.39%)	35 (37.6%)	4 (4.3%)	1 (1.07%)	23 (24.73)	0	30 (32.3%)
Inclined	20 (14.49%)	7 (35%)	0	5 (25%)	2 (10%)	0	6 (30%)
Inverted	11 (7.97%)	10 (90.9%)	0	0	1 (11.1%)	0	0
Transversal	6 (4.34%)	5 (83.3%)	0	1 (16.7%)	0	0	0
Eruption status	<0.001
Impacted	125 (90.5%)	54 (43.2%)	0	2 (1.6%)	27 (21.6%)	2 (1.6%)	40 (32%)
Semi-impacted	2 (1.44%)	1 (50%)	0	0	1 (50%)	0	0
Erupted	11 (7.97%)	5 (45.5%)	4 (36.4%)	0	2 (18.2%)	0	0

Although most of the ST found in our study were impacted (90.5%) they usually caused no complications (71.7%). When complications were observed they were mostly presented as retention of permanent teeth (16.7%), diastema (5.1%) change in position/shape of PT (3.6%), enlargement of follicular space (2.2%) and resorption of an adjacent tooth (0.7%) (Table 3) (Figure 3).

Table 3. Complication of ST in relation to descriptive data for 138 ST.

	No complications	Retention of permanent tooth	Change of position/shape of PT	Diastema	Follicular space enlargement	Resorption of the adjacent tooth	p
Type of tooth Mesiodens Distomolar Paramolar Parapremolar SN lateral incisor SN Canine	99(71.7%) 31(51.7%) 38(95%) 1(50%) 25(83.3%) 3(75%) 1(50%)	23(16.7%) 21(35%) 1(2.5%) 0 0 1(25%) 0	5(3.6%) 4(6.7%) 1(2.5%) 0 0 0 0	7(5.1%) 3(5%) 0 0 4(13.3%) 0 0	3(2.2%) 1(1.7%) 0 1(50%) 0 0 1(50%)	1(0.7%) 0 0 0 1(3.3%) 0 0	<0.001
Arch Maxilla Mandible	74(69.2%) 25(80.6%)	22(20.6%) (3.2%)	5(4.47%) 0	4(3.7%) 3(9.7%)	2(1.9%) 1(3.2%)	0 1(3.2%)	<0.05
Morphology							<0.01
Conic Supplementary Tuberculate Localization Oral	30(63.8%) 31(62%) 38(92.7%) 64(65.3%) 30(88.2%) 5(83.3%)	12(25.5%) 10(20%) 1(2.4%) 22(22.4%) 1(2.9%) 0	3(6.4%) 1(2%) 1(2.4%) 3(3.1%) 1(2.9%) 1(16.7%)	1(2.1%) 6(12%) 0 5(5.1%) 2(5.9%) 0	1(2.1%) 1(2%) 1(2.4%) 3(3.1%) 0 0	0 1(2%) 0 1(1%) 0 0	>0.05
In line
Vestibular
Orientation Horizontal Vertical Inverted Inclined Transveral Eruption status Impacted Semi-impacted Erupted	7(87.5%) 69(74.2%) 9(81.8%) 11(55%) 3(50%) 93(74.4%) 0 6(54.5%)	1(12.5%) 15(16.1%) 0 5(25%) 2(33.3%) 21(16.8%) 1(50%) 1(9.1%)	0 4(4.3%) 0 1(5%) 0 3(2.4%) 0 2(18.2%)	0 3(3.2%) 2(18.2%) 2(10%) 0 4(3.2%) 1(50%) 2(18.2%)	0 1(1.1%) 0 1(5%) 1(16.7%) 3(2.4%) 0 0	0 1(1.1%) 0 0 0 1(0.8%) 0 0	>0.05 <0.01

Out of the studied sample, 28% of patients were surgically treated, 16% of patients with ST although having associated complications opted not to have them surgically removed.

4.2. Bivariate analysis

Bivariate analysis showed a statistically significant relationship (p<0.001) between the type of ST and location (maxilla/mandible) (Table 2). Most frequently found ST in maxilla were mesiodens and distomolar (55.1% and 31.8%) whereas s parapremolar was associated with mandibular presentation (71%).

Similarly, the relation between ST type and morphology was statistically significant. Most of the conical ST were mesiodens (83%), parapremolar was associated with supplementary (50%) and distomolar with tuberculate morphology (80.5%) (Table 2).

According to our study significant association between the type of ST and their orientation was also observed (p<0.005). Vertical orientation was associated with mesiodens as 37.6% vertically oriented ST were mesiodens. Furthermore, inverted and transversal orientation were almost exclusively presented by mesiodens as 90.9% of inverted ST, and 83.3% transversal ST were mesiodens (Table 2).

Further analysis was made for potential associations between complications and various characteristics of ST which is presented in Table 3. Our results demonstrated that the occurrence of ST-associated retention of adjacent teeth was significantly correlated to the type of tooth. For example, impaction of the adjacent tooth and malposition and change of shape of PT was almost exclusively found in presence of mesiodens.

5. DISCUSSION

The prevalence of ST in our study that was conducted among the Caucasian population is low – 0.98%, but it falls within the reported range of 0.8% to 2.1% for Caucasians (15). The prevalence of ST seems to be affected by race as authors report prevalence of 3.4% for Japanese (16) and 6% for African Americans (17). Gender predilection for ST was previously established as most authors report male predominance regarding the prevalence of ST. This notion was affirmed by our study with the predominance of ST in male.

Regarding the number of ST per patient previous studies have documented single ST in 76-86% of patients, and 14-31% of the studied sample had multiple ST presentations (6, 18, 19). The present study obtained a similar percentage. According to previous studies ST are more likely to be found in the maxilla in up to 10 to 1 proportion (16, 20). Most of the ST in our study were also found in the maxilla which is in concordance with the findings of Bereket et al. and Brinkmann et al. (7, 11). Particularly rare was the finding of ST in mandibular anterior region, a notion that was previously established. Furthermore, as in the previous findings mesiodens was the most frequently found ST, followed by distomolars and parapremolars (6,11). Most of the ST were normally oriented in our study as was found by Rajab et al. but differs from findings of Liu et al., and Jiang et al. (6, 18, 19). This could be explained by racial differences and with the fact that most of our radiographic images were 2D unlike the studies conducted by Liu et al. and Jiang et al. which used 3D imaging. Our study has shown an even distribution of conical (34.05%) supplementary (36.23%), and tuberculate (29.71%) morphology with supplementary morphology taking the lead. According to most studies ST usually present conical morphology (2,6, 18, 21). Furthermore, this study obtained supplementary morphology in a much higher percentage than the studies by Anthonappa et al., De Oliveira Gomes et al., and Rajab et al. who found supplementary ST to be present in the range of 6.9-16.7% (3, 18, 20). As in the findings of Jiang et al. and Ma et al. connection between the ST morphology and type was observed as 82.97% of conical ST in our study were mesiodentes while 80.5% of tuberculate ST were distomolars. As 71.7 % of ST presented no complications, our study was in concordance with the statement that ST is usually discovered during routine radiographic observation, when a concerned parent notices that a permanent tooth failed to erupt. In that context, mechanical obstruction is the most common complication caused by ST. Brinkmann et al. found that 25.1% of ST-associated pathology was in the form of mechanical obstruction and Celikoglu et al. observed delayed eruption in 16.7% of cases, unlike Ma et. al that recorded malposition of adjacent tooth as the most common complication (2, 7, 22). Similar to the previous findings was ours where retention of permanent tooth was present in 16.7% of cases which is 58.98% of associated pathology found in our study, and is followed by malposition of a permanent tooth. Unlike our study Park et al., as well as Jiang et al., found a relation between ST morphology, position, and crown orientation and complications in their studies which could be explained by a greater sample size (6, 13).

6. CONCLUSION

Our study documented the prevalence, clinical and radiographic characteristics of 138 ST found in nonsyndromic patients in B&H. The present study found prevalence of ST in this population to be low, that ST are usually found in anterior maxilla in form of mesiodens which are mostly conically shaped, orally positioned and vertically oriented. Although associated pathology was not high early diagnosis allows optimal patient management which reduces later complications. Knowledge of ST characteristics is very important for different dental specialties especially in setting timely diagnosis and providing the best therapy.

Authors’ contributions:

Conception and design: NH, AH, AM. Acquisition, analysis and interpretation of data: NH, AH, AM, LHB, ADZ, SK, IT. Drafting the article: NH, AH, AM. Revising it critically for important intellectual content: NH, AH, AM, ADZ, SK, IT, LHB. Approved final version of the manuscript: NH, AH, AM, ADZ, SK, IT, LHB.

Conflict of interest:

The authors declare that they have no conflict of interest.

Financial support and sponsorship:

Ni.l