Abstract

Objective:

Considering that the available studies on prevalence of malocclusions are local or national-based, this study aimed to pool data to determine the distribution of malocclusion traits worldwide in mixed and permanent dentitions.

Methods:

An electronic search was conducted using PubMed, Embase and Google Scholar search engines, to retrieve data on malocclusion prevalence for both mixed and permanent dentitions, up to December 2016.

Results:

Out of 2,977 retrieved studies, 53 were included. In permanent dentition, the global distributions of Class I, Class II, and Class III malocclusion were 74.7% [31 - 97%], 19.56% [2 - 63%] and 5.93% [1 - 20%], respectively. In mixed dentition, the distributions of these malocclusions were 73% [40 - 96%], 23% [2 - 58%] and 4% [0.7 - 13%]. Regarding vertical malocclusions, the observed deep overbite and open bite were 21.98% and 4.93%, respectively. Posterior crossbite affected 9.39% of the sample. Africans showed the highest prevalence of Class I and open bite in permanent dentition (89% and 8%, respectively), and in mixed dentition (93% and 10%, respectively), while Caucasians showed the highest prevalence of Class II in permanent dentition (23%) and mixed dentition (26%). Class III malocclusion in mixed dentition was highly prevalent among Mongoloids.

Conclusion:

Worldwide, in mixed and permanent dentitions, Angle Class I malocclusion is more prevalent than Class II, specifically among Africans; the least prevalent was Class III, although higher among Mongoloids in mixed dentition. In vertical dimension, open bite was highest among Mongoloids in mixed dentition. Posterior crossbite was more prevalent in permanent dentition in Europe.

Keywords:
Prevalence; Malocclusion; Global health; Population; Permanent dentition; Mixed dentition.

Resumo

Objetivo:

considerando-se que os estudos disponíveis sobre a prevalência das más oclusões são de base local ou nacional, esse estudo teve como objetivo reunir dados para determinar a distribuição dos tipos de má oclusão em uma escala global, nas dentições permanente e mista.

Métodos:

foi realizada uma busca eletrônica através das ferramentas de pesquisa do PubMed, Embase e Google Acadêmico, para reunir estudos publicados até dezembro de 2016 sobre a prevalência das más oclusões, tanto na dentição permanente quanto na dentição mista.

Resultados:

dos 2.977 estudos encontrados, 53 foram analisados. Na dentição permanente, a distribuição mundial das más oclusões de Classe I, II e III foi, respectivamente, de 74,7% [31 - 97%], 19,56% [2 - 63%] e 5,93% [1 - 20%]. Na dentição mista, a distribuição dessas más oclusões foi de 73% [40 - 96%], 23% [2 - 58%] e 4% [0,7 - 13%]. Em relação às más oclusões verticais, observou-se prevalência de 21,98% de sobremordida profunda e 4,93% de mordida aberta. A mordida cruzada posterior afetou 9,39% da amostra. Os africanos mostraram a maior prevalência de Classe I e mordida aberta na dentição permanente (89% e 8%, respectivamente) e na dentição mista (93% e 10% respectivamente), enquanto os caucasianos apresentaram a maior prevalência de Classe II na dentição permanente (23%) e na dentição mista (26%). A má oclusão de Classe III na dentição mista foi mais prevalente entre xantodermas.

Conclusão:

mundialmente, nas dentições mista e permanente, as más oclusões de Classe I de Angle são mais prevalentes do que as de Classe II, especificamente entre os africanos; a menos prevalente foi a Classe III, ainda que mais prevalente entre os xantodermas na dentição mista. Na dimensão vertical, as mordidas abertas foram mais prevalentes entre xantodermas na dentição mista. A mordida cruzada posterior apresentou maior prevalência na dentição permanente na Europa.

Palavras-chave:
Prevalência; Má oclusão; Saúde global; População; Dentição permanente; Dentição mista.

INTRODUCTION

Angle introduced his famous classification of malocclusion in 1899.¹1 Angle EH. Classification of malocclusion. Dent Cosmos. 1899;41:248-64. Now the World Health Organization estimates malocclusions as the third most prevalent oral health problem, following dental caries and periodontal diseases.²2 Guo L, Feng Y, Guo HG, Liu BW, Zhang Y. Consequences of orthodontic treatment in malocclusion patients: clinical and microbial effects in adults and children. BMC Oral Health. 2016 Oct 28;16(1):112.

Many etiological factors for malocclusion have been proposed. Genetic, environmental, and ethnic factors are the major contributors in this context. Certain types of malocclusion, such as Class III relationship, run in families, which gives a strong relation between genetics and malocclusion. Likewise is the ethnic factor, where the bimaxillary protrusion, for example, affects the African origin more frequently than other ethnicities. On the other hand, functional adaptation to environmental factors affects the surrounding structures including dentitions, bone, and soft tissue, and ultimately resulting in different malocclusion problems. Thus, malocclusion could be considered as a multifactorial problem with no specific cause so far.³3 Heimer MV, Tornisiello Katz CR, Rosenblatt A. Non-nutritive sucking habits, dental malocclusions, and facial morphology in Brazilian children: a longitudinal study. Eur J Orthod. 2008 Dec;30(6):580-5.

A search in the literature for studies on prevalence of malocclusion and related factors revealed that most of these epidemiological investigations were published between the 1940s and the 1990s. Thereafter, publications have been turned into focusing more on determination of treatment needs, treatment techniques and mechanisms, and treatment outcomes.⁴4 Brook PH, Shaw WC. The development of an index of orthodontic treatment priority. Eur J Orthod. 1989 Aug;11(3):309-20.

Epidemiological studies play a pivotal role in terms of determining the size of the health problems, providing the necessary data and generating and analyzing hypotheses of associations, if any. Through these valuable information, the priorities are set and the health policies are developed.⁵5 Foster TD, Menezes DM. The assessment of occlusal features for public health planning purposes. Am J Orthod. 1976 Jan;69(1):83-90. Hence, the quality of these epidemiological studies must be evaluated crucially and it will be valuable to pool their results, whenever possible.

In this regard, there has been a continuous increase in conducting critical analyses for the published epidemiological health studies. The aim behind this is to generate a more precise and trusted evidence on the health problem under investigation using strict criteria for quality analysis. However, few have been conducted in orthodontics. The objective of the current study, therefore, was to present a comprehensive estimation on the prevalence of malocclusion in different populations and continents.

MATERIALS AND METHODS

Search method

A literature search in PubMed, Embase, and Google Scholar search engines was conducted up to December 2016. The following search terms were used: ‘Prevalence’, ‘Malocclusion’, ‘Mixed dentition', and 'Permanent dentition’. In addition, an electronic search in websites of the following journals was conducted: Angle Orthodontist, American Journal of Orthodontics and Dentofacial Orthopedics, Journal of Orthodontics, and European Journal of Orthodontics.

Studies that fulfilled the following criteria were included:

A study was excluded if it was conducted in a clinical/hospital-based setting and/or targeted malocclusion prevalence in primary dentition or in a population with specific medical problem.

Characteristics of all studies⁶6 Massler M, Frankel JM. Prevalence of malocclusion in children aged 14 to 18 years. Am J Orthod 1951;37(10):751-68.

7 Goose DH, Thompson, D.G., and Winter, F.C. Malocclusion in School Children of the West Midlands. Brit Dent J. 1957;102:174-8.

8 Mills LF. Epidemiologic studies of occlusion. IV. The prevalence of malocclusion in a population of 1,455 school children. J Dent Res. 1966;45:332-6.

9 Grewe JM, Cervenka J, Shapiro BL, Witkop CJ Jr. Prevalence of malocclusion in Chippewa Indian children. J Dent Res. 1968 Mar-Apr;47(2):302-5.

10 Helm S. Malocclusion in Danish children with adolescent dentition: an epidemiologic study. Am J Orthod. 1968 May;54(5):352-66.

11 Thilander B, Myrberg N. The prevalence of malocclusion in Swedish schoolchildren. Scand J Dent Res. 1973;81(1):12-21.

12 Foster TD, Day AJ. A survey of malocclusion and the need for orthodontic treatment in a Shropshire school population. Br J Orthod. 1974 Apr;1(3):73-8.

13 Ingervall B, Mohlin B, Thilander B. Prevalence and awareness of malocclusion in Swedish men. Community Dent Oral Epidemiol. 1978 Nov;6(6):308-14.

14 Helm S, Prydso U. Prevalence of malocclusion in medieval and modern Danes contrasted. Scand J Dent Res. 1979 Apr;87(2):91-7.

15 Lee KS CK, Ko JH, Koo CH. Occlusal variations in the posterior and anterior segments of the teeth. Korean J Orthod. 1980;10:70-9.

16 Gardiner JH. An orthodontic survey of Libyan schoolchildren. Br J Orthod. 1982 Jan;9(1):59-61.

17 Muniz BR. Epidemiology of malocclusion in Argentine children. Community Dent Oral Epidemiol. 1986 Aug;14(4):221-4.

18 Kerosuo H, Laine T, Kerosuo E, Ngassapa D, Honkala E. Occlusion among a group of Tanzanian urban schoolchildren. Community Dent Oral Epidemiol. 1988 Oct;16(5):306-9.

19 Woon KC, Thong YL, Abdul Kadir R. Permanent dentition occlusion in Chinese, Indian and Malay groups in Malaysia. Aust Orthod J. 1989 Mar;11(1):45-8.

20 al-Emran S, Wisth PJ, Boe OE. Prevalence of malocclusion and need for orthodontic treatment in Saudi Arabia. Community Dent Oral Epidemiol. 1990 Oct;18(5):253-5.

21 El-Mangoury NH, Mostafa YA. Epidemiologic panorama of dental occlusion. Angle Orthod. 1990 Fall;60(3):207-14.

22 Lew KK, Foong WC, Loh E. Malocclusion prevalence in an ethnic Chinese population. Aust Dent J. 1993 Dec;38(6):442-9.

23 Tang EL. The prevalence of malocclusion amongst Hong Kong male dental students. Br J Orthod. 1994 Feb;21(1):57-63.

24 Harrison RL, Davis DW. Dental malocclusion in native children of British Columbia, Canada. Community Dent Oral Epidemiol. 1996 June;24(3):217-21.

25 Ng'ang'a PM, Ohito F, Ogaard B, Valderhaug J. The prevalence of malocclusion in 13- to 15-year-old children in Nairobi, Kenya. Acta Odontol Scand. 1996 Apr;54(2):126-30.

26 Ben-Bassat Y, Harari D, Brin I. Occlusal traits in a group of school children in an isolated society in Jerusalem. Br J Orthod. 1997 Aug;24(3):229-35.

27 Proffit WR, Fields HW Jr, Moray LJ. Prevalence of malocclusion and orthodontic treatment need in the United States: estimates from the NHANES III survey. Int J Adult Orthodon Orthognath Surg. 1998;13(2):97-106.

28 Dacosta OO. The prevalence of malocclusion among a population of northern Nigeria school children. West Afr J Med. 1999 Apr-June;18(2):91-6.

29 Saleh FK. Prevalence of malocclusion in a sample of Lebanese schoolchildren: an epidemiological study. East Mediterr Health J. 1999 Mar;5(2):337-43.

30 Esa R, Razak IA, Allister JH. Epidemiology of malocclusion and orthodontic treatment need of 12-13-year-old Malaysian schoolchildren. Community Dent Health. 2001 Mar;18(1):31-6.

31 Thilander B, Pena L, Infante C, Parada SS, de 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 Apr;23(2):153-67.

32 Freitas MR, Freitas DS, Pinherio FH, Freitas KMS. Prevalência das más oclusöes em pacientes inscritos para tratamento ortodôntico na Faculdade de Odontologia de Bauru-USP. Rev Fac Odontol. 2002;10(3):164-9.

33 Bataringaya A. Survey of occlusal trait in an adolescent population in Uganda. Cabo: University of the Western Cape; 2004.

34 Onyeaso CO. Prevalence of malocclusion among adolescents in Ibadan, Nigeria. Am J Orthod Dentofacial Orthop. 2004 Nov;126(5):604-7.

35 Tausche E, Luck O, Harzer W. Prevalence of malocclusions in the early mixed dentition and orthodontic treatment need. Eur J Orthod. 2004 June;26(3):237-44.

36 Abu Alhaija ES, Al-Khateeb SN, Al-Nimri KS. Prevalence of malocclusion in 13-15 year-old North Jordanian school children. Community Dent Health. 2005 Dec;22(4):266-71.

37 Ali AH AM. Prevalence of Malocclusion in a Sample of Yemeni Schoolchildren: an epidemiological study. Abstracts Yemeni Health Med Res. 2005;44:44.

38 Behbehani F, Artun J, Al-Jame B, Kerosuo H. Prevalence and severity of malocclusion in adolescent Kuwaitis. Med Princ Pract. 2005 Nov-Dec;14(6):390-5.

39 Ciuffolo F, Manzoli L, D'Attilio M, Tecco S, Muratore F, Festa F, et al. Prevalence and distribution by gender of occlusal characteristics in a sample of Italian secondary school students: a cross-sectional study. Eur J Orthod. 2005 Dec;27(6):601-6.

40 Karaiskos N, Wiltshire WA, Odlum O, Brothwell D, Hassard TH. Preventive and interceptive orthodontic treatment needs of an inner-city group of 6- and 9-year-old Canadian children. J Can Dent Assoc. 2005 Oct;71(9):649.

41 Ahangar Atashi MH. Prevalence of Malocclusion in 13-15 Year-old Adolescents in Tabriz. J Dent Res Dent Clin Dent Prospects. 2007 Spring;1(1):13-8.

42 Gelgor IE, Karaman AI, Ercan E. Prevalence of malocclusion among adolescents in central anatolia. Eur J Dent. 2007 July;1(3):125-31.

43 Jonsson T, Arnlaugsson S, Karlsson KO, Ragnarsson B, Arnarson EO, Magnusson TE. Orthodontic treatment experience and prevalence of malocclusion traits in an Icelandic adult population. Am J Orthod Dentofacial Orthop. 2007 Jan;131(1):8.e11-8.

44 Josefsson E, Bjerklin K, Lindsten R. Malocclusion frequency in Swedish and immigrant adolescents--influence of origin on orthodontic treatment need. Eur J Orthod. 2007 Feb;29(1):79-87.

45 Ajayi EO. Prevalence of Malocclusion among School children in Benin City, Nigeria. J Biomed Res. 2008;7(1-2):58-65.

46 Mtaya M, Astrom AN, Brudvik P. Malocclusion, psycho-social impacts and treatment need: a cross-sectional study of Tanzanian primary school-children. BMC Oral Health. 2008 May 6;8:14.

47 Borzabadi-Farahani A, Borzabadi-Farahani A, Eslamipour F. Malocclusion and occlusal traits in an urban Iranian population. An epidemiological study of 11- to 14-year-old children. Eur J Orthod. 2009 Oct;31(5):477-84.

48 Daniel IB PF, Rogerio G. Prevalência de más oclusões em crianças de 9 a 12 anos de idade da cidade de Nova Friburgo (Rio de Janeiro). Rev Dental Press Ortod Ortop Facial. 2009;14(6):118-24.

49 Sidlauskas A, Lopatiene K. The prevalence of malocclusion among 7-15-year-old Lithuanian schoolchildren. Medicina (Kaunas). 2009;45(2):147-52.

50 Alhammadi M. The prevalence of malocclusion in a group of Yemeni adult population: an epidemiologic study [thesis]. Cairo: Cairo University; 2010.

51 Bhardwaj VK, Veeresha KL, Sharma KR. Prevalence of malocclusion and orthodontic treatment needs among 16 and 17 year-old school-going children in Shimla city, Himachal Pradesh. Indian J Dent Res. 2011 July-Aug;22(4):556-60.

52 Nainani JT, Relan S. Prevalence of Malocclusion in School Children of Nagpur Rural Region - An Epidemiological Study. J Dental Assoc. 2011;5:865-7.

53 Bugaighis I. Prevalence of malocclusion in urban libyan preschool children. J Orthod Sci. 2013 Apr;2(2):50-4.

54 Kaur H, Pavithra US, Abraham R. Prevalence of malocclusion among adolescents in South Indian population. J Int Soc Prev Community Dent. 2013 July;3(2):97-102.

55 Reddy ER, Manjula M, Sreelakshmi N, Rani ST, Aduri R, Patil BD. Prevalence of Malocclusion among 6 to 10 Year old Nalgonda School Children. J Int Oral Health. 2013 Dec;5(6):49-54.

56 Bilgic F, Gelgor IE, Celebi AA. Malocclusion prevalence and orthodontic treatment need in central Anatolian adolescents compared to European and other nations' adolescents. Dental Press J Orthod. 2015 Nov-Dec;20(6):75-81.

57 Gupta DK, Singh SP, Utreja A, Verma S. Prevalence of malocclusion and assessment of treatment needs in beta-thalassemia major children. Prog Orthod. 2016;17:7.^-5858 Narayanan RK, Jeseem MT, Kumar TA. Prevalence of Malocclusion among 10-12-year-old Schoolchildren in Kozhikode District, Kerala: An Epidemiological Study. Int J Clin Pediatr Dent. 2016 Jan-Mar;9(1):50-5. analyzed were formulated similar to that used in analysis of epidemiological studies⁵⁹59 Mattheeuws N, Dermaut L, Martens G. Has hypodontia increased in Caucasians during the 20th century? A meta-analysis. Eur J Orthod. 2004 Feb;26(1):99-103.^,6060 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 June;32(3):217-26. (Table 1).

Critical appraisal of the included studies was done based on a modified version of STROBE checklist⁶¹61 Vandenbroucke JP, von Elm E, Altman DG, Gotzsche PC, Mulrow CD, Pocock SJ et al. Strengthening the Reporting of Observational Studies in Epidemiology (STROBE): explanation and elaboration. Int J Surg. 2014;12:1500-24.^,6262 Kalakonda B, Al-Maweri SA, Al-Shamiri HM, Ijaz A, Gamal S, Dhaifullah E. Is Khat (Catha edulis) chewing a risk factor for periodontal diseases? A systematic review. J Clin Exp Dent. 2017;9:e1264-70. comprising seven items related to: study design, study settings, participants criteria, sample size, variable description, and outcome measurements. The quality of the studies was categorized into weak (≤ 3), moderate (4 or 5) and high quality (≥ 6), as described in Table 2.

Statistical analysis

Prevalence rates, by different variables, were presented as means and standard deviations (SD), with the minimum and maximum values. The data were checked for normal distribution using Kolmogorov-Smirnov test. As the distribution was not normal, analyses were conducted using non-parametric tests. Kruskal-Wallis test was used for comparisons between more than two groups. Mann-Whitney U test was used for pair-wise comparisons between groups whenever Kruskal-Wallis test was significant. Spearman's coefficient was calculated to determine the correlations, if any, between different variables. All tests were supposed to be two-tailed, and the power and the significance values were set at 0.8 and 0.05, respectively. Statistical analysis was performed with IBM^® SPSS^® Statistics for Windows software, version 21 (Armonk, NY: IBM Corp.)

RESULTS

Two thousands nine hundreds and seventy seven studies were found to be potentially relevant to the study. The flow diagram (Fig 1) describes the process of articles retrieval; 255 articles were excluded due to duplication. The main cause of dropping of the retrieved articles was removal of irrelevant titles (2,348). The final closely related were 374 articles published between years 1951 and 2016. After reading their abstracts, only 53 articles (Table 1) fulfilled the inclusion criteria and were included in the subsequent analyses.

The results of the critical appraisal of the included studies are presented in Table 2. The total quality score ranged from 4 to 7. Thirty eight studies (72%) were considered of moderate quality and fifteen (28%), of high quality. The most common drawbacks among all studies were failure to declare the study design (whether it is of cross-sectional, follow-up, etc.) and lack of sample size calculation.

In permanent dentition (Table 3), the global distributions of Class I, Class II, and Class III were 74.7%, 19.56% and 5.93%, respectively. Increased and reverse overjet was recorded in 20.14% and 4.56%, respectively. Regarding vertical malocclusions, the observed deep overbite and open bite were 21.98% and 4.93%, respectively. Considering the transverse occlusal discrepancies, the posterior crossbite affected 9.39% of the total examined sample.

Regarding the distribution of malocclusion in adults according to geographical location (Table 4), four continents classification system was considered, in which Americas are considered as one continent. In permanent dentition, Europe showed the highest prevalence of Class II and posterior crossbite (33.51% and 13.8%, respectively), and the lowest prevalence of Class I (60.38%). This was applied to mixed dentition regarding Class I and Class II. No statistically significant differences in prevalence of Class III, increased overjet, reversed overjet, deep bite and open bite between the four geographic areas were reported.

In permanent stage of dentition by ethnic groups, the highest prevalences of Class I malocclusion and open bite (89.44% and 7.82%, respectively) were reported among African population, although the difference of the latter was not statistically significant. However, the highest prevalence of Class II (22.9%) was reported among Caucasians. Otherwise, no statistically significant differences were found in prevalence of Class III, increased overjet, reversed overjet, deep bite and posterior crossbite between the three main populations (Table 5).

The global distributions of Class I, Class II, and Class III in mixed dentition stage were 72.74%, 23.11% and 3.98%, respectively. The prevalence figures of increased and reverse overjet were 23.01% and 3.65%, respectively. Deep overbite and open bite cases were reported in 24.34% and 5.29%, respectively. Posterior crossbite represented 11.72% of the total pooled studies (Table 3).

Regarding prevalence of malocclusion in mixed dentition according to geographical location (Table 4), Africa showed the highest prevalence of Class I (90%) but the lowest prevalence of Class II malocclusions (7.5%). The highest prevalence figures of Class II, Class III, and open bite malocclusions were reported in Europe (31.95%), Asia (5.76%), and Africa (8.3%), respectively. Deep bite was significantly higher in Europe (37.4%) compared to other geographical areas.

In mixed dentition, African population showed the highest prevalence of Class I (92.47%), but the lowest prevalence of Class II malocclusions (5.1%), while Caucasians showed the lowest prevalence of open bite (3.7%). Mongoloid showed significantly higher prevalence of Class III (10.95%). No significant differences in the prevalence of other malocclusions were found between different ethnicities (Table 5).

The prevalence of Class II was observed less frequently in permanent than in mixed dentition (19.56 ± 13.76 and 23.11 ± 14.94%, respectively), while the prevalence of Class III was observed more frequently in permanent than in mixed dentition (5.93 ± 4.96 and 3.98 ± 2.75, respectively).

DISCUSSION

Global, regional and racial epidemiological assessment of malocclusions is of paramount importance, since it provides important data to assess the type and distribution of occlusal characteristics. Such data will aid in determining and directing the priorities in regards to malocclusion treatment need, and the resources required to offer treatment - in terms of work capacity, skills, agility and materials to be employed. In addition, assessment of malocclusion prevalence by different populations and locations may reflect existence of determining genetic and environmental factors. In line with that, the hypothesized tendency of changing prevalence of a specific type of malocclusion, such as Class II, from mixed to permanent dentition stage may give an indication about the effect of adolescent growth in correction of this problem. Finally, the availability of such global data will be important for educational purposes. Regional and/or racial-specific malocclusion may change the health policy toward developing the specialists’ skills and offering the resources required for that malocclusion. It must be emphasized that the current study summarizes the global distribution of malocclusion in mixed and permanent dentitions based on data extracted from studies of moderate (72% of the included studies) to high (28%) quality. None of the included studies was of low quality.

The pooled global prevalence of Class I was the highest (74.7 ± 15.17%), ranging from 31% (Belgium) to 96.6% (Nigeria). It was higher among Africans (89.44%), but equivalent among Caucasians and Mongoloids (71.61% and 74.87%, respectively). This pattern of distribution was reported for both dentitions with slight differences. Noteworthy, the prevalence of Class I in permanent dentition of Mongoloids tends to increase with pubertal growth, mostly due to the associated tendency for Class II correction in this race specifically.

The overall global prevalence of Class II was 19.56%. However, it was interesting to see a wide range from 1.6% (Nigeria) to 63% (Belgium). The lowest prevalence was reported for Africans 6.76% and the highest was reported for Caucasian (22.9%); the reported prevalence for Mongoloids was in-between (14.14%). The pattern of global distribution of Class II malocclusion by race was somewhat similar in mixed and permanent dentitions. With exception of African people (Africa), there is a tendency for correction of Class II with pubertal growth upon transition from mixed to permanent dentition. Both, prevalence and growth correction of Class II, can be attributed to the genetic influence. Recent research emphasizes the pivotal role of genetic control over condylar cartilage and condylar growth.⁶³63 Shibata S, Suda N, Suzuki S, Fukuoka H, Yamashita Y. An in situ hybridization study of Runx2, Osterix, and Sox9 at the onset of condylar cartilage formation in fetal mouse mandible. J Anat. 2006 Feb;208(2):169-77.^,6464 Hinton RJ. Genes that regulate morphogenesis and growth of the temporomandibular joint: a review. Dev Dyn. 2014 July;243(7):864-74.

The global prevalence of Class III was the lowest among all Angle’s classes of malocclusion (5.93 ± 4.69%). The range was interestingly wide: 0.7% (Israel) to 19.9% (China). The corresponding figures for Caucasians, Africans and Mongoloids were 5.92, 3.8% and 9.63%, respectively. This pattern of global distribution of Class III applies to mixed and permanent dentitions. A tendency to develop this type of malocclusion appears to increase upon transition from mixed to permanent dentition among Africans and Caucasians, rather than among Mongoloids. The role of genetics must be emphasized. In fact, Class III malocclusion in Asians is mainly due to the mid-face deficiency, rather than mandibular prognathism.⁶⁵65 Newman GV. Prevalence of malocclusion in children six to fourteen years of age and treatment in preventable cases. J Am Dent Assoc. 1956 May;52(5):566-75.

The positive correlation found between Class II and increased overjet is logical. Simply, this is due to the fact that the most prevalent Class II malocclusion globally is Class II division 1.⁶⁶66 Silva Filho OG, Ferrari Junior FM, Okada Ozawa T. Dental arch dimensions in Class II division 1 malocclusions with mandibular deficiency. Angle Orthod. 2008 May;78(3):466-74. Similarly, the positive correlation of Class III malocclusion with reversed overjet is related to skeletal base discrepancy with minimal dentoalveolar compensation.⁶⁷67 Kim SJ, Kim KH, Yu HS, Baik HS. Dentoalveolar compensation according to skeletal discrepancy and overjet in skeletal Class III patients. Am J Orthod Dentofacial Orthop. 2014 Mar;145(3):317-24.

The lowest prevalent malocclusion traits globally were reversed overjet and open bite (4.56 and 4.93, respectively). There is a high variation in prevalence of both traits as reported in the literature. Most of the studies reported that open bite trait is highly prevalent in African populations and low in Caucasian populations,¹⁷17 Muniz BR. Epidemiology of malocclusion in Argentine children. Community Dent Oral Epidemiol. 1986 Aug;14(4):221-4.^,1818 Kerosuo H, Laine T, Kerosuo E, Ngassapa D, Honkala E. Occlusion among a group of Tanzanian urban schoolchildren. Community Dent Oral Epidemiol. 1988 Oct;16(5):306-9.^,2020 al-Emran S, Wisth PJ, Boe OE. Prevalence of malocclusion and need for orthodontic treatment in Saudi Arabia. Community Dent Oral Epidemiol. 1990 Oct;18(5):253-5.^,2525 Ng'ang'a PM, Ohito F, Ogaard B, Valderhaug J. The prevalence of malocclusion in 13- to 15-year-old children in Nairobi, Kenya. Acta Odontol Scand. 1996 Apr;54(2):126-30. in contrast to the reversed overjet, which reported to be prevalent in Mongoloids. In general, both traits are genetically determined.⁶³63 Shibata S, Suda N, Suzuki S, Fukuoka H, Yamashita Y. An in situ hybridization study of Runx2, Osterix, and Sox9 at the onset of condylar cartilage formation in fetal mouse mandible. J Anat. 2006 Feb;208(2):169-77.^,6464 Hinton RJ. Genes that regulate morphogenesis and growth of the temporomandibular joint: a review. Dev Dyn. 2014 July;243(7):864-74.

An interesting finding was the higher prevalence of Class II malocclusion in the mixed dentition than in the permanent dentition. This could be explained by the fact that self-correction of a skeletal Class II problem might occur in the late mixed and early permanent dentition stage as a result of a potential mandibular growth spurt. However, a sound conclusion can’t be drawn, as the present study was not prospective. In addition, the difference in leeway space between maxillary and mandibular arches, and residual growth in the permanent dentition stage could explain the higher prevalence of Class III malocclusion in the permanent dentition than in the mixed dentition, and the fact that the mandible might continue to grow till the mid- twenties.

The present pooled data showed a decrease in the prevalence of deep bite upon transition from mixed to permanent dentition. Thilander et al,³¹31 Thilander B, Pena L, Infante C, Parada SS, de 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 Apr;23(2):153-67. likewise, showed that increased overbite was more prevalent in the mixed dentition. Such an overbite reduction from the mixed to the permanent dentition is due to both occlusal stabilization involving full eruption of premolars and second molars, and the more pronounced mandibular growth.³⁵35 Tausche E, Luck O, Harzer W. Prevalence of malocclusions in the early mixed dentition and orthodontic treatment need. Eur J Orthod. 2004 June;26(3):237-44. This also explains the reduction in Class II cases as well as the increase in Class III cases (reverse overjet as well) during the period of changing dentition.

In addition to the importance of reporting global malocclusion, it is of an equal importance to report the worldwide orthodontic treatment needs. We planned to do so if the included studies had covered both issues. This was not the case, however, and hence we recommend addressing this latter issue with a similar systematic review.

CONCLUSIONS

REFERENCES

Publication Dates

History