PREVALENCE OF MALOCCLUSION AMONG YEMENI CHILDREN OF PRIMARY SCHOOLS

Tharwa Ali Mokred AL-Awadi¹, Khaled A AL-Haddad¹ , Mohammed A Al-labani²,

Hassan Abdulwahab Al-Shamahy³ Hussein M Shaga-aldeen¹

¹Orthodontics, Pedodontics and Prevention Department Faculty of Dentistry, Sana'a University, Yemen.

²Orthodontics, Pedodontics and Prevention Department Faculty of Dentistry, Sana'a University, Yemen.

³Departement of Basic Sciences, Faculty of Dentistry, Sana’a University, Republic of Yemen.

ABSTRACT

Objective: Malocclusion is every difference in the arrangement of teeth beyond the standard of regular occlusion illustrated by anomalies within the dental arches. The purpose of this study was to measure prevalence of malocclusion between primary school children in Sana’a city Yemen.

Methods: A cross sectional study was conducted on 1079 school children (546 girls and 533 boys), their age ranged from 7 to 12 years old from public and private schools selected randomly in Sana'a City, Yemen. The prevalence of malocclusion was investigated according to age, gender and school type based on Angle's classification.

Results: The study showed that the overall prevalence of malocclusion among school children was 81.1%, in which Class I normal molar association was found only in 18.9% of school children, while Class I malocclusion included the highest percentage of the sample 70.4%, followed by Class II relation 9.5%, and Class III involved only 1.1%. The most prevalent malocclusion trait was spacing 35.7%, whereas the crowding was present in 30.0% of the sample. The deep bite was present in 10.1% followed by anterior crossbite 8.8%, midline diastema 8.6%, anterior open bite 4.5%, posterior crossbite 4.0%, and the least noted malocclusion trait was posterior open bite 0.4%.

Conclusion: In conclusion, there was a high rate of malocclusion in school children and significantly increased with age, class I malocclusion was the most common followed by Class II malocclusion, while Class III was the rear. The most prevalent occlusal problem was spacing, followed by crowding.  Thus, 7-12 year-olds can benefit from interceptive and preventive oral health procedures which may either entirely prevent or reduce the development of serious types of malocclusions afterward in their lives.

Keywords: Malocclusion, prevalence, primary school children, Yemen

INTRODUCTION

Research and study of dental health problems in Yemen are still modest and limited, although there have been studies that have addressed the problems of tooth decay, gum infections, causes for extraction of permanent teeth and prevalence and pattern of third molar impaction in adults and children^1,2,3,4,5  but no research has touched upon malocclusion. Malocclusion is a problem of the oral cavity scattered around the world, from which the children and adults suffer, not less important than other oral problems. Although dental malocclusion is not a life-threatening condition⁶, the poor periodontal conditions⁷ and impaired mastication⁸ associated with it provoke the need to explore the prevalence of malocclusion in different age groups. Furthermore, it is one of the most common dental problems, together with dental caries, gingival disease and dental fluorosis⁹. It is considered as dental public health problem, its impact psychologically and functionally is great, and its prevalence among children is high¹⁰. In addition to that, malocclusion is thought to be a risk factor information and progression of dental caries. Since pediatric patients with malocclusion have challenged the ability to practice effective oral hygiene, this may predispose them to malocclusion¹¹. Concerning premature loss of primary teeth, it has been previously stated that the premature loss of primary teeth can affect the normal eruption time of the permanent successors by either retarding or accelerating their emergence¹². It is considered a predisposing factor for occlusal and space discrepancies in the mixed and permanent dentitions¹³. Consistent with the World Health Organization, the main dental problems should be subjected to regular epidemiological evaluations. Knowledge of a population's epidemiological condition is vital for planning and offering prevention and treatment services¹⁴. The understanding of the epidemiological status of different characters of malocclusion among the special population is essential for planning the need and provision for orthodontic service to improve the quality of life¹⁵_. Dental malocclusion prevalence among school children have been reported in most countries of the world. There were few studies on the prevalence of malocclusion in Yemen, and only two studies were conducted in Sana’a City in 2014  by Al-Zubair and Ghandour¹⁶, and Al-Zubair and Al- Almulla¹⁷. It is clear to see the need to study prevalence of malocclusion  in Yemeni school children during mixed dentition period to provide basic values for preventive measures and then to know and reduce the potential irregularities in the developing dental-facial complex in future. The importance of this study comes from the great effects of malocclusion defects on children's oral, systemic and psychological health.

SUBJECTS AND METHODS

This descriptive cross-sectional study was conducted to measure the prevalence of malocclusion among Yemeni school children of primary schools (Government and private) in Sana'a City, Yemen. A total of 1079 boys and girls aged between 7-12 years old from schools of Sana’a were randomly selected and examined, the schools are located in different regions of the city to avoid having children from the same area.

Table 1: The distribution of school children participants in the study according

to age, gender, school type and district (n=1079)

Mean age ±SD= 9.5±1.7

The data collection was performed by one examiner; the researcher (Tharwa), by using the standard method¹⁸. The clinical examination for each child with dental and medical history was formed by simple inspection under adequate light, sometimes if the natural light was insufficient, artificial light from a torch was utilized. All children were examined in a room of the school selected by the principles of the school. Those children who were selected and refused to participate were excluded replaced with new one.

Before starting the study, ethical considerations were taken after the approval of the study by the Faculty of Dentistry in Sana'a University, Yemen. The examination was conducted with permission from the concerned education authorities. Permission was obtained from the office of the region education and the principals of the targeted schools and after obtaining informed consent from parents of the participating children The examination assessed the period of dentition and analysis of occlusal data, by using a separate registration chart designed to record the personal data of the subjects (all information and clinical examination).

Table 2: The prevalence of malocclusion according to age, gender and school type

* P< 0.05 statistically significant

Statistical Analysis

The data were analyzed by SPSS program (IBM Corp. Released 2012. IBM SPSS Statistics for Windows, Version 21.0. Aromnk, NY: IBM Corp.) and presented by using tables. Percentage (%) was used to describe the qualitative variables. Chi-square with Yate correction and Fisher tests were used to show the significance of the association between the outcomes at the level of significance less than 0.05 (P).

RESULTS

The results in Table 2 indicate that the prevalence of total malocclusion among school children was 81.1%, and there was significant difference between malocclusion according to age group 7-9 years old (84.2%) and 10-12 years (78.1%). Also a similar prevalence of malocclusion was found in boys and girls, government schools, and private schools (Table 2). The results in (Table 3) indicate that class I malocclusion has the highest proportion of the sample 70.4%, with 73.2% in the 7-9 age group higher than the 10-12 age group (67.8%) (P<0.05). The class II malocclusion was at 9.5%, while the class III had the lowest incidence and was only present in 1.1% of the entire sample.

Table 3: Prevalence of Angle classification according to age, gender and school type

* P< 0.05 statistically significant

According to age, there was significant difference with class II malocclusion (P< 0.05). On the other hand, a normal class I occlusion was in 18.9% of the sample. 21.9% were found for age group 10-12 years older more than that of age group 7-9 years (15.8%), also the age difference was significant. The most prevalent malocclusion trait was spacing 35.7%. According to age groups, the highest rate of spacing was found in 7-9 years old 42.0%, comparing to age group 10-12 years old 29.7% (X²=17.76, P<0.001), while non-significant difference of spacing malocclusion was found regarding gender and school type (Table 4). The proportion of school children with dental crowding was 30.0%, with a non-significant difference that in age groups, gender and school type (P > 0.05) (Table 5).

Table 4: Prevalence of spacing according to age, gender and school type and the association of spacing with premature loss of teeth

** P< 0.001 statistically significant

The most prevalent malocclusion trait was spacing 35.7%, whereas the crowding was present in 30.0% of the sample. The deep bite was present in 10.1% followed by anterior crossbite 8.8%, midline diastema 8.6%, anterior open bite 4.5%, posterior crossbite 4.0%, and the least noted malocclusion trait was posterior open bite 0.4% (Table 6).

DISCUSSION

The prevalence of malocclusion varies from country to country and between different age and nationality groups. Globally, epidemiological studies indicate that the prevalence of malocclusion is between 39% and 93%¹⁸. In the present study, malocclusion was demonstrated in 81.1% of the school children. By comparing the result of this study to other studies, there was almost an agreement with the following reported studies¹⁴ 80.84%,¹⁹ 86.6%, and²⁰ 83.3%. 

Table 5: Prevalence of crowding according to age, gender and school type

Alternatively, this result was slightly higher when compared to Almeida et al.,²¹ 73%, (Reddy et al.,²² 52%, Morais et al.,²³ 78.50%, Disha et al.,²⁴ 40.9%, Sultan,²⁵ 78.31%, and Yu et al.,²⁶ 79.4%. The variation in the prevalence of malocclusion can be attributed to the differences in the age ranges of the populations studied, the number of subjects examined and differences in the registration methods which are probably the most important factors explaining these variations⁹_.

Table 6:  The association of  occlusal  problem with age groups, gender and school type.

Regarding gender, no statistical significant difference (P > 0.05) was observed between boys and girls with respect to the prevalence of malocclusion (Table 2), coinciding with Das et al.,²⁷ ; Souza et al.,²⁸; Narayanan et al.,²⁰. According to age groups, the prevalence of malocclusion was more noticeable for the age group 7-9 years compared to the age group 10-12 years, with a statistical significant difference (P < 0.05). This finding is consistent with Morais et al.,²³. Variation in malocclusion can appear between age groups due to age and individual differences, or perhaps a shift from Class II malocclusion to the normal occlusion that occurs from the mesial movement of the first molars in the lower jaw where the second primary molars exfoliated²⁵_. The prevalence of normal occlusion was found low in the present study (18.9%) comparing with other studies by Alatrach et al.,²⁹ (38.5%), Reddy et al.,²² (48.30%), Al-Zubair and Ghandour,¹⁶ (69.4%), and Disha et al.,²⁴ (59.1%). However, this result almost corresponds with the data in some other studies by Souza et al.,²⁸ (22.3%), Morais et al.,²³ ( 21.50%), and by Narayanan et al.,²⁰ (16.7%). These disparities between the high malocclusion and low normal occlusion prevalence that was found in this study may explain the low preventive measure and treatment services.

The results of this study showed that Class I malocclusion prevailed over Class II and Class III (Table 3), in agreement with the majority of the previous studies^23-28. On the other hand, few  studies by Gonçalves et al.,³³;  Freitas et al., ³⁴; and by  Yu et al.,²⁶ emphasized the predominance of Class II, in comparison with relation Class I and Class III. This variation of results may be explained by the regional differences, age and sample size, or by the fact of considering normal occlusion as being Class I and maybe by the diversity of the used methodology²⁶. Furthermore, Class I malocclusion included the highest proportion of the sample 70.4% (Table 3). This finding resembles³² who found that the most common malocclusion was Class I 70.4%.

This finding also coincides with results of other studies, where malocclusion of Class I was found to be the predominant one by Brito et al.,¹⁴  (76.7%), Bourzgui et al.³¹  (61.4%), Narayanan et al.,²⁰  ( 69.8%), and by Sultan,²⁵  (65.87%). In contrary Class I malocclusion in this study was  higher than that found by Souza et al.,²⁸ 47.6%, Almeida et al.,²¹  (55.25%), Romano et al.,¹⁹  (55.7%), Reddy et al.,²² (30.3%), Alatrach et al.,²⁹  (30%), and  by Disha et al.,²⁴  (36.4%) studies. In terms of Class II malocclusion, a prevalence of 9.5% was found in the present study. This result is almost similar to the findings of  Narayanan et al.,²⁰ (9.3%) in contrast higher rate of Class II  in that reported by Brito et al.,¹⁴ (19.2%), Almeida et al.,²¹ (38%), Bourzgui et al.,³¹ (24%), Reddy et al.,²² (13.9%), Sultan,²⁵ (21.93%), and  by Alajlan et al.,³²  (21.3%), while our result was higher than that reported by  Disha et al.,²⁴ 

(3.9%). On the other hand, Class III malocclusion was found only in 1.1% (Table 3). This result was higher when compared to finding of  Disha et al.,²⁴  0.6%, and lower as compared to that of Souza et al.,²⁸  (8.2%), Brito et al.,¹⁴ ( 4.2%), Lux et al.,³⁰ (3%), Almeida et al.,²¹ (6.75%), Bourzgui et al.,³¹ (10%), Romano et al.,¹⁹ (6.0%), Reddy et al.,²² (7.8%), Alatrach et al.,²⁹ (12%), Narayanan et al.,²⁰ (4.1%),  Sultan,²⁵ (12.18%), Alajlan et al.,³² (8.3%), and by Yu et al.,²⁶ (5.9%). In the present study, the most prevalent malocclusion trait was spacing 35.7% (Table 4). This result higher when compared to Al-Zubair and Al- Almulla¹⁷ (25.8%). This large number of school children with spacing is due to the fact that most of them had a premature loss of teeth mostly the primary teeth losing. There was statistic significant difference between the two age groups, which was found higher for age group 7-9 years    old 42.0%, compared to the 10-12 years old 29.7%. By comparing with other studies, this result is much higher than that found by Disha et al.,²⁴ (6.5%) and by Yu et al.,²⁶ (9.5%). The second most common type of malocclusion trait in this study was crowding seen in 30.0% of school children (Table 5). This finding is almost in agreement with that of Almeida et al.,²¹ (31.59%), Al-Zubair and Ghandour,¹⁶ (31.4%), Al-Zubair and Al- Almulla,¹⁷ (30.4%), and by Yu et al.,²⁶ (28.4%). However, the number of crowding in this study is much lower than that reported by Souza et al.,²⁸ (49.6%), Brito et al.,¹⁴ (45.5%), and by Romano et al.,¹⁹ (52.6%).

According to gender, a non-significant difference in crowding was observed (P>0.05) (Table 5). This finding is in agreement with Brito et al.,¹⁴, and in disagreement with Souza et al.,²⁸  who found a significant difference between genders (P < 0.05) in which the dental crowding in girls was higher than in boys. On the other hand, the results has shown that there is a higher prevalence of dental crowding for age group 7-9 years old than for age group 10-12 years old (Table 5). This result is in agreement with that found by Morais et al.²³. This may be partially explained by the fact that some dental crowding may have, spontaneously, resolved. Mixed dentition crowding, known as temporary primary crowding, may resolve spontaneously during the stage of mixed dentition^35,36_.

CONCLUSION

There was a high rate of malocclusion in school children and significantly increased with age, class I malocclusion was the most common followed by Class II malocclusion, while Class III was the rear. The most prevalent occlusal problem was spacing, followed by crowding. This study could open the field of specific studies to determine the means for the proper identification, control, and guidance of the environmental factors that could affect the craniofacial structures, which would be the main target of the preventive programs. Thus, 7-12 year-olds can benefit from preventive and interceptive oral health measures, which may totally either prevent or lessen the development of severe forms of malocclusions later in their lives.

AUTHOR'S CONTRIBUTION

This research work is part of a Master's thesis. The candidate is the first author (TAA) to conduct clinical work and thesis. Corresponding author (HAA), second author (KAA) and third author (MAA) supervised the work, revised and edited the thesis draft and the manuscript.

ACKNOWLEDGMENTS

The authors would like to acknowledge Sana'a University, Sana'a, Yemen which supported this work.

CONFLICT OF INTEREST   

No conflict of interest associated with this work.

REFERENCES

1. Al-Sharani AA, Al-Hajj W, Al-Shamahy HA, Jaadan BM. The effect of nanosilver and chlorhexidine mouthwash on anaerobic periodontal pathogens counts. Univ J Pharm Res 2019; 4(5): 1-6. DOI: https://doi.org/10.22270/ujpr.v4i5.309
2. Al-Shamahy HA, Abbas AMA, Mahdie Mohammed AM, Alsameai AM. Bacterial and Fungal Oral Infections Among Patients Attending Dental Clinics in Sana’a City-Yemen. On J Dent Oral Health 2018; 1(1): 1-6https://doi.org/10.33552/OJDOH.2018.01.000504

3. Alhadi Y, Al-Shamahy HA, Aldilami A, Al-Hamzy M, Al-Haddad KA, et al. Prevalence and Pattern of Third Molar Impaction in Sample of Yemeni Adults. On J Dent Oral Health 2019; 1(5):https://doi.org/10.33552/OJDOH.2019.01.000523

4. Al-Shami IZ, Al-Shamahy HA, Abdul Majeed ALA, Al- Ghaffari KM and Obeyah AA. Association between the salivary Streptococcus Mutans levels and dental caries experience in adult females. On J Dent Oral Health 2018; 1(1): https://doi.org/10.33552/OJDOH.2018.01.000505
5. Alhadi Y, Rassem AH, Al-Shamahy HA, Al-Ghaffari KM. Causes for extraction of permanent teeth in general dental practices in Yemen. Univ J Pharm Res 2019; 4(2): 1-5. https://doi.org/10.22270/ujpr.v4i2.249
6. Karaiskos N, Wiltshire W.A, Odlum O, Brothwell D, Hassard T.H. Preventive and interceptive orthodontic treatment needs of an inner-city group of 6 and 9 years old Canadian children. J Can Dent Assoc 2005; 71(9): 649.
7. Ngom P.I, Diagne F, Benoist H.M, Thiam F. Intra arch and inter arch relationships of the anterior teeth and periodontal conditions. Angle Orthod 2006; 76(2): 236-242.
8. Ngom PI, Diagne F, Aïdara-Tamba AW, Sene A. Relationship between orthodontic anomalies and masticatory function in adults. Am J Orthod Dentofacial Orthop 2007; 131(2): 216-22. https://doi.org/10.1016/j.ajodo.2005.03.027
9. Dhar V, Jain A, Van Dyke T.E, Kohli A. Prevalence of gingival diseases, malocclusion and fluorosis in school-going children of rural areas in Udaipur district. J Indian Soc Pedod Prev Dent 2007; 25(2): 103-5. https://doi.org/10.4103/0970-4388.33458
10. Mtaya M, Brudvik P, Astrom A.N. Prevalence of malocclusion and its relationship with sociodemographic factors, dental caries, and oral hygiene in 12 to 14 years old Tanzanian school children. European J Ortho 2009; 31(5): 467-476. https://doi.org/10.1093/ejo/cjn125
11. Helma S, Petersena P.E. Pressure habits, etiological factors in malocclusion 1989; 47(4): 223-229.https://doi.org/10.1016/0002-9416(52)90025-0

12. Leite-Cavalcanti A, Menezes S.A, Granville-Garcia AF, Correia-Fontes LB. Prevalence of early loss of primary molars: study retrospective. Acta Sci Health Sci 2008; 30(2): 139-43.
13. Baskaradoss J.K, Geevarghese A, Roger C, Thaliath A. Prevalence of malocclusion and its relationship with caries among school children aged 11-15 years in Southern India. Korean J Orthod 2013; 43(1): 35-41.https://doi.org/10.4041/kjod.2013.43.1.35

14. Brito DI, Dias PF, Gleiser R. Prevalence of malocclusions in children aged 9 to 12 years in the city of Nova Friburgo (Rio de Janeiro). Dental Press Ortodon Ortoped Facial 2009; 14(6): 118-124.https://doi.org/10.1590/S1415-54192009000600014 

15. Singh SP, Kumar V, Narboo P. Prevalence of malocclusion among children and adolescents in various school of Leh region. J Orth Endo 2015; 1(2):15.
16. Al-Zubair NM, Ghandour IA. Occlusal status among Yemeni children. APOS Trends Orthod 2014; 4(4): 93-8.https://doi.org/10.4103/2321-1407.135794

17. Al-Zubair N.M, Almulla A. Malocclusion traits of Yemeni female school children. Orth J Nepal 2014; 4(1): 41-44.https://doi.org/10.3126/ojn.v4i1.11310

18. Thilander B, Pena L, Infante C, Parada SS, Mayorga C. Prevalence of malocclusion and orthodontic treatment need in children and adolescents in Bogota, Colombia. An epidemiological study related to different stages of dental development. Eur J Orthod 2001; 23(2): 153-67.https://doi.org/10.1093/ejo/23.2.153

19. Romano FL, Magnani MBBA, Ferreira JTL, Matos DS, Valério RA, Silva RAB, Filho PN. Prevalence of malocclusions in school children with mixed dentition in the city of Piracicaba, Brazil. Rev Odontol Univ Cid São Paul 2012; 24(2): 96-104. https://doi.org/10.26843/ro_unicid.v24i2.361

20. Narayanan RK, Jeseem MT, Kumar TVA. Prevalence of malocclusion among 10-12 years old school children in Kozhikode District, Kerala: An epidemiological study. Int J Clin Pediatr Dent 2016; 9(1): 50-55. https://doi.org/10.5005/jp-journals-10005-1333

21. Almeida MR, Pereira ALP, Almeida RR, Almeida-Pedrin RR, Silva Filho OG. Prevalence of malocclusion in children aged 7 to 12 years. Dental Press J Orthod 2011; 16(4): 123-31. https://doi.org/10.1590/S2176-94512011000400019
22. Reddy ER, Manjula M, Sreelakshmi N, Rani S.T, Aduri R, Patil BD. Prevalence of Malocclusion among 6 to 10 Years old Nalgonda School Children. J Int Oral Health 2013; 5(6): 49-54.
23. Morais CH, Zanin L, Degani VV, Valdrighi HC, Venezian GC, Vedovello SAS. Malocclusion in schoolchildren aged 7-12 years old in Minas Gerais, Brazil. RGO, Rev Gaúch Odontol, Porto Alegre 2016; 64(2): 164-170. https://doi.org/10.1590/1981-863720160002000062970

24. Disha P, Poornima P, Pai SM, Nagaveni NB, Roshan NM, Manoharan M. Malocclusion and dental caries experience among 8-9 years old children in a city of South Indian region: A cross-sectional survey. J Edu Health Promot 2017; 6: 98. https://doi.org/10.4103/jehp.jehp_24_17
25. Sultan S. Prevalence of malocclusion among 12 years old school children in Kashmir India. Sch J Den. Sci 2018; 5(1): 35-39.
26. Yu X, Zhang H, Sun L, Pan J, Liu Y, Chen L. Prevalence of malocclusion and occlusal traits in the early mixed dentition in Shanghai, China. Peer J 2019; 7: e6630. https://doi.org/10.7717/peerj.6630

27. Das UM, Venkatsubramanian, Reddy Prevalence of malocclusion among school children in Bangalore, India. Int J Clin Pediatr Dent 2008; 1(1): 10-12. https://doi.org/10.5005/jp-journals-10005-1002

28. Souza RA, Magnani MBB, Nouer DF, Romano FL, Passos MR. Prevalence of malocclusion in a Brazilian school children population and its relationship with early tooth loss. Braz J Oral Sci 2008; 7(25): 1566-1570. https://doi.org/10.20396/bjos.v7i25.8642937

29. Alatrach AB, Saleh FK, Osman E. The prevalence of malocclusion and orthodontic treatment need in a sample of Syrian children. Eur J Orthod 2014; 10(30): 153-67.
30. Lux CJ, Ducker B, Pritsch M, Komposch G, Niekusch U. Occlusal status and prevalence of occlusal malocclusion traits among 9 years old schoolchildren. European J Orth 2009; 31(3): 294-99. https://doi.org/10.1093/ejo/cjn116
31. Bourzgui F, Sebbar M, Hamza M, Lazrak L, Abidine Z, El Quars F. Prevalence of malocclusions and orthodontic treatment need in 8 to 12 years old school children in Casablanca, Morocco. Prog Orthod 2012; 13(2): 164-72. https://doi.org/10.1016/j.pio.2011.09.005

32. Alajlan SS, Alsaleh MK, Alshammari AF, Alharbi SM, Alshammari AK, Alshammari RR. The prevalence of malocclusion and orthodontic treatment need of school children in Northern Saudi Arabia. J Orthodont Sci 2019; 8(10): 1-5. https://doi.org/10.4103/jos.JOS_104_18
33. Gonçalves LPV, Toledo AO, Otero SAM. Relationship between bruxism, occlusal factors and oral Dental Press J Orthod 2010; 15(2): 97-104. https://doi.org/10.1590/S2176-94512010000200013

34. Freitas CV, Souza JGS, Mendes DS, Pordeus IA, Jones KM, Martins AMEBL. Need for orthodontic treatment in Brazilian adolescents: Evaluation based on public health.  Rev Paul Pediatr 2015; 33(2): 204-10. https://doi.org/10.1016/j.rpped.2014.04.006

35. Moyers R. Orthodontics. 3^rd Rio de Janeiro: Guanabara- Koogan 1988; 669. Silva Filho OG, Garib DG, Lara TS. Interceptive orthodontics: Two-phase treatment protocol. São Paulo: Artes Médicas 2013; 574.