Prevalence of Malocclusion and Orthodontic Treatment needs in Qena Governorate, Egypt: An Epidemiological study with reviewing similar studies in some countries
Laila Abdel-Fattah Amer^1* Abdel-Fattah M Amer²

1. Lecturer of Orthodontics, Faculty of Oral and Dental Medicine, MTI University, Cairo, Egypt

2. Professor of Periodontology and Oral Medicine, Faculty of Dental Medicine, Cairo, Al-Azhar University

Corresponding Author: Laila Abdel-Fattah Amer, Lecturer of Orthodontics, Faculty of Oral and Dental Medicine, MTI University, Cairo, Egypt.

Copy Right: © 2021 Laila Abdel-Fattah Amer, this is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.  

Received Date: October 03, 2021

Published date: November 01, 2021

Abstract

Background: The present study was designed and performed in an attempt to assess prevalence of malocclusion (its incidence, classes and treatment needs) and searching for possible association with potential risk indicators in one of Upper Egypt Governorates (QENA). Reviewing of previous similar work in several countries all over the world was highlighted. Methods: Total sample of 1392 subjects aged from 10 – 34 years old (698 males and 694 females) from different areas in Qena governorate.

Descriptive questionnaire was prepared and obtained from all sample’s subjects, full personal data was recorded, and subjects were examined in a dental chair using dental chair light, mouth mirror, explorer, periodontal probe; entire mouth was examined in a uniform pattern.

Teeth occlusion state was determined according to criteria of Angle’s classification, and Orthodontic treatment needs were recorded from subjects possessed abnormal occlusion relationships, using questionnaire applying criteria of IOTN.

Results: Normal occlusion was recorded in 1005 subjects (72.2 %), while 387 showed malocclusion (27.8 %); Class I type (21.2 %), Classes II type (5.3 %), and Class III type (1.3 %). There were no differences between females and males regarding prevalence of malocclusion as well as distribution of malocclusion types and abnormal bite types, and not affected by geographic location inside Qena governorate. The results showed that 31.90 % of all included subjects were in need to have orthodontic treatment Grades 4 and 5, whereas 32.43% of subjects were in Grade 3 (borderline), while 35.67 % of subjects did not require orthodontic treatment (they were below Grade 1); statistically significant differences (p < 0.05) between subjects did not require orthodontic treatment (Grades 1 and 2) and other groups required orthodontic treatment (Grade 3 and Grades 4 &5), but these two last groups did not differ significantly (p> 0.05).

Conclusion: Slightly more than quarter of Qena governorate population, Egypt, had teeth malocclusion with no differences regarding gender type as well as geographic location. Regarding orthodontic treatment needs, it seems likely that nearly one third of examined subjects were in need to have treatment, one third were on borderline, while last third not in need to have treatment.

Keywords: Malocclusion prevalence, Occlusion types distribution, Egypt, Orthodontic

Introduction

Malocclusion can be defined as an abnormality in growth and development of teeth; it may adversely affect quality of life of affected individuals, impairing their social interaction and psychological well– being,(1,2) due to impaired facial esthetics, weakened functions of speech, chewing and swallowing.(3) It is not a disease, but a morphological variation that occurs worldwide, regardless of gender, ethnic group and social class;(4-8) may be associated with facial skeletal disharmony which may be a reason to seek treatment toward  the improvement of body image and social acceptance.(9) Malocclusion features the third highest prevalence among oral pathologies, secondarily to dental caries and periodontal disease.(10) Thus, epidemiologic assessment is necessary to clarify its aspect and to plan beneficial treatment.(11)Malocclusions can be assessed using various methods(12-15) but no one has gained universal acceptance. Index of Orthodontic Treatment Need (IOTN) was developed to grade malocclusion on basis of various occlusal traits significance for dental health and esthetic impairment (16) It incorporates a dental health component (DHC) based on recommendations of Swedish medical board and an esthetic component.(17) The Dental Aesthetic Index (DAI) has been recommended by WHO to gather information of malocclusion prevalence and orthodontic treatment need worldwide.(11) Angle’s classification of malocclusion developed in 1890s was the corner stone in orthodontics, as it includes the first clear and simple definition of normal natural human occlusion.(18) Despite many drawbacks and many newer classifications available today, Angle’s classification is still the most widely used in epidemiological studies. Its major drawback is that it had taken into account only anteroposterior deviations in sagittal plane. Thus, reliability testing of intra-/ inter-examiner errors showed relatively high figures. (19)

A systematic review and meta-analysis of 77 of studies from 2009 to 2019, declared that the worldwide prevalence of malocclusion among children and adolescents was 56% with no gender difference. Higher percentage noted in Africa (81%), in Europe (71%), in America (53%) and Asia 48%.(20) Danish children and adolescents aged 9 to 18 years showed that 14% had normal occlusion, 58% had Class I, 24% had Class II and about 4% had Class III malocclusion,4 while less normal occlusion and more Class I was noted in Norwegian children aged 7 to 8 years; normal occlusion was 1.3%, Class I was 30.1%, Class II was 21.3%, and Class III was 7.3%.21 An ethnically Chinese children 12 to 14 years of age in Australia showed that 7.1% had normal occlusion, 58.8% had Class I, (21).5% had Class II and 12.6% had Class III malocclusion. (22) The USA survey found that 50% of children group had well-aligned incisors and remaining had some degree of crowding/misalignment; severe Class II and Class III problems were seen in 4% of the population; 30% showed normal occlusion; Class I  was 50 % - 55 %, Class II was 5%, and less than 1% had Class III malocclusion.(23) Brazilian schoolchildren with mixed dentition showed occlusal problems of 49.0% in deciduous dentition and 71.3% in permanent dentition.(24) In India malocclusion varies from 20 - 43 % (25) and in Jaipur (26) about 66.7% had malocclusion and only 33.3% had normal occlusion; highest was Class I (57.9%), while Cass III was the least (1.4%), prevalence of Class II division 2 (1.9%) and Class III (1.4%).

An Indian survey(27) of children in remote villages showed that malocclusion was only 14.4%; a majority of these (10.5%) were mild malocclusion, 3.7% had moderate to severe malocclusion; 80.1% of school children had little or no malocclusion requiring no or little orthodontic treatment need, 19.9% of school children had malocclusion requiring elective to mandatory orthodontic treatment. In Nagpur, Class I was 77.29%, Class II 5.04% and Class III 2.50%, and occlusal variation is independent of sex.(28) In Jammu, subjects aged between 13-14 years 83% had malocclusion. Class I 67%, Class II div One 8%, Class II div Two 6%, and Class III 2% of sample size.(29) Hence, a definite ethnic trend in prevalence of malocclusion type in India from north to south noted; prevalence of class II in Bangalore (5%) was much lower compared to 10—15% in Delhi.27

Malocclusion in China was evaluated through a total of (31) qualified research describing 51,100 Chinese children aged 2–7 years. The pooled malocclusion prevalence was 45.50%; Class I was 26.50% Class II was 7.97%, and Class III was 12.60%. The overbite was more prominent (33.66%), with no significant difference in malocclusion by gender or urban/rural area.(30) Nigerian school children (229 males and 212 females) showed that 15.9% had normal occlusion, 80.7% had Class I and 1.1% had Class II div 1, 0.5% had Class II div 2 and 1.8% Class III malocclusion.(31) Tanzanian work on malocclusion prevalence and its association with socio-demographic characteristics, caries experience, and level of oral hygiene among 1601 schoolchildren aged between 12- to 14-years found that majority (93.6 %) showed a Class I while Class II and Class III malocclusions were reported in 4.4 and 2.0 %, respectively.(32) Kenyan school children reported that 39% had malocclusion, (33) while  Sudanese children sample showed 78% with Class I followed by class II (11%) and class III (3%).34 A random sample of 200 Syrian children aged between 8 to 13 years found one third of sample had moderate to great need for orthodontic treatment, no difference in treatment need regarding the genders.(35) In Al-Najaf city, Iraq  two groups (788 females & 584 males) aged 12-17 years reported that Class I was 88.04%, whereas 8.03% showed Class II Div.1, 1.31 % exhibit Class II Div. 2 and Class III was 2.3%. Class I showed maximum prevalence, followed by Class II/1 and Class III, while Class II/2 showed the lowest percentage. (36) A descriptive cross-sectional random study of adolescents Saudi Arabia reported that Class I was 52.8%, Class II was 31.8%, and Class III was 15.4%.37 Prevalence of malocclusion in Israeli population (95.9%). (38)

El-Hadary and Aboul-Azm (39) evaluated malocclusion in 600 Egyptian adult males recorded Class I in 52% while 8% and 4% of them had class II and III respectively. The occlusal variation among Egyptian adults in 501 subjects (age 14 - 24 years) found that 34.3% had normal occlusion while 65.5% showed malocclusion; classes I, II, III were 33.3%, 21%, and 11.3% respectively.(40) Prevalence of malocclusion among school children in Cairo governorates was screened in 1936 schoolchildren and found that 497 children (25.7%) had accepted occlusion while, 997 children had Class I malocclusion (51.5%), 318 children had Class II (16.4%) while 115 children had Class III and 9 children had Class IV (0.5%). The most frequent category was normal overjet (>0–3.5mm) which was found to be (71.8%). Anterior open bite (<0 mm) was found in (5.9%). There was a tendency toward decrease in the prevalence of accepted occlusion while, there was an increase in Angle Class II and III malocclusion.(41) Another Egyptian study showed that 497 children (25.7%) had accepted occlusion while, 997 children had Angle Class I malocclusion (51.5%), 318 children had Class II (16.4%), while 115 children had Class III (5.9%), and 9 children had Class IV (0.5%) of the study sample. Normal overjet (>0–3.5mm) found to be (71.8%), and anterior open bite (<0 mm) was found in (5.9%) of the total sample.(42) The present study was undertaken to shed some light on prevalence of malocclusion in one of Egyptian governorates as a part from a whole survey covering several areas in Egypt.

Subjects and Method

Sample Size Calculation:

Qena governorate is one of Egyptian governorates, located in the southern part of the country (600 km south of Cairo), it covers a stretch part of Nile valley and its capital is Qena city. Its area is 9565 km2 with population of 3302894 (representing 3.4 % from Egyptian population); it includes 9 cities with a population of 614864 and a total of 152 villages with a population of 2688030, living on only 199.4 km2. Included sample size was calculated on basis of Egyptian population consensus (2018); Egyptian population between ages of 10 – 34 years was 40603425 (representing 41.39 % from total population), while same age groups of Qena population was 1392102 (41.63 % from its population). Based on these data a total of 1392 subjects (0.1 % from these age groups (698 males and 694 females) from different cities and villages were randomly included from each area determined proportionately depending on percentage of total population (Table 1); this survey was conducted over a period of six months of the year 2019. The study protocol was reviewed and ethical clearance was obtained before the start of the study from the Ethical approval Committee of Faculty of Dental Medicine, Al-Azhar University, Cairo, Egypt. An official permission was obtained from Qena authority of health and population. The parent / guardian of the child provided the consent on behalf of the patient.

Inclusion / Exclusion Criteria: (a) Children, young adults, and adults of both genders born to Egyptian parents having an age range from 10-34 years, (b) Presence of incisors teeth and first permanent molars on the both jaws, were included, while subjects with craniofacial anomalies that affect jaw relation and dentition, facial trauma or surgery history, presence of systemic diseases that affect craniofacial growth, and previous orthodontic treatment were excluded.

Methods:

I. Clinical Examination:

A Questionnaire was prepared; its forum included questions concerning age, education level, socio-economic level, systemic and oral health status, habits, smoking, and tooth brushing use. A group of dentists were enrolled in well training course regarding the proper screening of the patient in dental practice to collect the questioner data from participants and to determine the state of teeth occlusion, either normal occlusion or malocclusion. Following this trained course two dentists working at each geographic location were chosen to perform that job, while the final decision regarding determination of malocclusion types as well as biting condition was carried out by one person (the main examiner). Subjects were examined in dental chair in an upright position under good artificial illumination by a single examiner after obtaining the informed consent from them / their parents prior to clinical examination. They were instructed to occlude on posterior teeth to assess anteroposterior, vertical and transverse dental relations using latex gloves, mouth mirrors and electronic digital caliper. After that he / she were asked to open the mouth for intra-oral assessment.

Malocclusion was recorded according to Angle’s classification, (18) as following: 

Accepted Occlusion: categorized if molar relationship showed normal occlusion (mesiobuccal cusp of upper first permanent molar occluded in anterior buccal groove of lower first permanent molar), average overbite 1-4mm, average overjet (>0 to3.5mm) with proper teeth alignment.

Class I Malocclusion: when mesiobuccal cusp of maxillary first permanent molar occluded with buccal groove of mandibular first molar, where the teeth were approximated in centric occlusion.

Class II Malocclusion:  when lower first permanent molar was positioned distally more than one half unit (>3 mm) relative to upper first permanent molar.

Class III Malocclusion: lower first permanent molar was mesially positioned more than half unit (> 3mm) relative to upper first permanent molar.

II.  Orthodontic Treatment Need:

Was assessed for subjects exhibiting any type of malocclusion applying the criteria of IOTN.17 Orthodontic treatment grades using DHC of IOTN index were recorded for each subject are assorted as Grade 1 (no treatment need), Grade 2 (mild need), Grade 3 (moderate need), Grade 4 (severe need) and Grade 5 (extreme need). Subjects with malocclusion were asked about the reason for seeking / not seeking orthodontic treatment.

Statistical analysis

Qualitative data were presented as frequencies and percentages, Numerical data were presented as mean; standard deviation (SD). Data were analyzed using Statistical Package for Social Sciences Windows, version 15.0 (SPSS, Chicago, IL, USA). Categorical variables were analyzed using chi-square test of Pearson to determine differences in prevalence rates between genders. P value for statistical significance was set at 0.05.

Results

The distribution of occlusion types, malocclusion types, recorded from the whole included sample, according to geographic location in Quena governorate, gender type as well as age groups was presented in Table 2 and 3, and Figures 1 and 2.

Distribution of Angle’s Malocclusion type according to Gender type:

A total of 295 subject had Class I malocclusion (21.3 %); they were 148 males (50.17 %) and 147 females (49.83 %); 75 subjects with Class II (Division I & II) malocclusion; they were 36 males (48 %) and 39 females (52 %) representing a ratio of 5.3 %, while only 17 subjects (9 males and 8 females) had Class III malocclusion, representing a ratio of 1.2 % (Fig. 3).

Treatment Needs Results:

The results showed that 31.90 % were in need to have orthodontic treatment Grades 4 and 5, whereas 32.43% of subjects were in Grade 3 (borderline), while 35.67 % of subjects did not require orthodontic treatment, as they were below Grade 1 and 2 (Table 3). The comparisons between them showed statistically significant differences (p ≤ 0.05) between subjects did not require orthodontic treatment (Grades 1 & 2) and the other groups required orthodontic treatment (Grade 3 and Grades 4 &5), but these two last groups did not differ significantly (p> 0.05).

Discussion

Malocclusion represents a relevant oral health problem and an economic burden for either family of affected children and dental health public services. Although malocclusion development may be due to genetics, environmental factors may be responsible as well. Lack of oral hygiene, large amounts of sugar intake, which leads to carious lesions of teeth and correspondingly early loss of deciduous teeth, little or no dental care in suburban locations, are factors that contribute to development of malocclusions. Malocclusion reaches its highest prevalence worldwide in early childhood during the deciduous dentition period (54%) and keeps unvaried in permanent dentition (54%).6, 11 Epidemiological surveys in any country provide a meaningful data and play an important role toward planning and implementation of dental services.

This is the first study to provide information about prevalence of malocclusion and orthodontic treatment needs among representative population sample from Governorate of Qena (Upper Egypt). Additionally, attention was paid to do reviewing of similar studies performed in other countries all over the world, to be able in discussing situation of malocclusion in Egypt with those in these countries. Prevalence of malocclusions as well as demand for orthodontic therapy has been studied in different ethnic groups’ yielded different data with great variability of the survey manner like developmental status, clinical examination method, sample size and characteristic of different ethnic groups. (20-22 )

The prevalence of malocclusion vary by country, age and sex; very few studies were carried out in Egypt to assess malocclusion prevalence.(39 – 42) the pooled global prevalence of Class I was highest (74.7 ± 15.17%), ranging from 31% (in Belgium) to 96.6% (in Nigeria), among Africans (89.44%), among Caucasians (71.61%) and Mongoloids (74.87%). Global prevalence of Class II reported a ratio of 19.56%, with a wide range from 1.6% (Nigeria) to 63% (Belgium); its lowest prevalence among Africans 6.76%, while the highest among Caucasian (22.9%). Global prevalence of Class III was the lowest (5.93 ± 4.69%); ranging from 0.7% (Israel) to 19.9% (China). A tendency to develop Class III malocclusion appears to increase upon transition from mixed to permanent dentition among Africans and Caucasians. (20)

The results of present study found that normal teeth occlusion had a ratio of 72.2%, much more than a previous Egyptian study 42 (27.5%), in Britain 43 (67.3%), in Libyans 44 (3%), Iranians 45 (4%) and Chinese 22 (7.1%). Prevalence of maloc¬clusion (27.8%) was lower than that of an Israeli population 38(95.9%); this difference could be due to different eth¬nic / environmental considerations. Class I malocclusion prevalence showed percentage of 21.35%, which was lower to that of a previous Egyptian study 42 (65.1%), Nigerian study 31 (50.0%). Angle Class II prevalence was (5.22%) in this study which is higher than that of a similar previous Egyptian study 42 (4.7%) and that of Tanzanian32 (3%), but less than reported in Kenyan populations 33 (7.9%) as well as in Turkey 46 (44.7%). Class III prevalence in present study was (1.23%) which was lower than that of previous Egyptian study 42 (2.7%) and those of Saudi Arabians37 (3%) as well as of Jordanians47 (1.4%).

Additionally, it was much lower than in Chinese population6 (19.9%), and Kenyan population33 (16.8%). An Egyptian study 39 assessed Angle’s malocclusion types in sample of 600 Egyptian male adults (18 years old in average) and found that Class I was 52%, while Class II and III showed ratio of 8% and 4% respectively. The findings of the present study did not lend support to these findings; such controversy can be attributed to sample size and age groups of the included sample. 

The results of this study showed that 295 subjects from a sample of 1392 (27.8%) exhibiting teeth malocclusion; Class I (21.2%), Class II (5. 3%) and (1.3%) had Class III. These results clearly declared that the most prevalent malocclusion was Class I followed by Class II, while the least prevalent malocclusion was Class III, which agree with Saudi study 37, but did not agree with that in Nigerian study and Turkish study; as they reported higher percentage of Class I malocclusion (76.5% and 74 %, respectively), as well as with an Iranian study on adolescents showed that, prevalence of Class I, Class II division 1, Class II division 2, and Class III malocclusions were 41.8%, 24.1%, 3.4%, and 7.8% respectively.

Same finding was reported from a study examined 16-year-old Jordanian school children and found that Class I was the most prevalent, followed secondly by Class II and at last Class III.47 Results, also, revealed that malocclusion was distributed, nearly, equal between the males (48 %) and the females (52 %); there was no significant difference in prevalence of malocclusions between genders, although other studies 48, 49 reported slight differences in the ratios between the genders. On the other hand, a significant difference in distribution of malocclusion between genders (23.7% among males and 28.8% among females) was reported in a Pakistani study. 50 It would be of hard task to draw any conclusion regarding reason for this difference, perhaps it may be attributed to the geographical features. Normal bite was detected in 67.6 %, a finding nearly similar to that of Saudi study found normal bite in 60.4 % of the included sample.(37)

Regarding the orthodontic treatment need determination, it was found that that 31.90 % of all included subjects were in need to have orthodontic treatment Grades 4 and 5, whereas 32.43% of subjects were in Grade 3 (borderline), while 35.67 % of subjects did not require orthodontic treatment, as they were below Grade 1 and 2 ; these findings agree with a study reported that approximately 30% of adolescent Kuwaiti females had a definitive orthodontic treatment need (Grades 4 and 5)51, and with findings of British school children sample categorized 34.8% in grades (1 or 2, no or little need respectively) and 33.2% in grade 3 (moderate need), and 32% in grades 4 or 5 (great or very great treatment need, respectively).(41)  However, this disagree with a study found that 18.39% of an Iranian population were severely need treatment; 25.8% were border line while 48.1% had a slight need and 7.63% had no need for treatment, 52  as well as with other studies  in  Hong Kong included male dental school students using Occlusal Index found that 41.7% need early orthodontic treatment and 24.1% need comprehensive orthodontic therapy for malocclusion management,33 Dutch study found that 39% was in need to treatment while only 14% were not in need.40 Additionally, the obtained results were far away from those of a study include Nepal school children aged 12- to 15-year-old, and found that 21.59% require extreme treatment need, 24.67% require severe treatment need, 24.07% require moderate treatment need, and 14.7% require mild treatment need, while 15.02% require no treatment need.53 Higher figures was reported by Turkish survey  that (47% ) of subjects had definite need for orthodontic treatment,54 although two other Turkish studies  reported that 92.53% 38  and 90.4 % of student 39didn’t feel the need of orthodontic treatment.

It is of interest to mention that, the responsibilities for orthodontic treatment are linked mainly on the patients / parents. Hence, the probability of seeking an orthodontic treatment has been influenced mainly by the cultural and socio-economic levels of the family, rather than by the patient’s malocclusion severity. Hence, degree and priority of orthodontic treatment need among populations cannot be verified just through evaluating the malocclusion prevalence. In this respect, new policies including early children’s visits to dental clinics, preventive as well as minimally invasive treatment procedures can be adopted early to validate an adequate preservation of oral health status. Further studies investigating the patient’s perception / concern regarding malocclusion prevalence / severity as well as orthodontic treatment needs should be carried out toward better clarification.

References

1. Milton B, Asbell A: A brief history of orthodontics. Am J Orthod 1990; 98(3): 206-13.

2. Hassan R, Rahimah A: Occlusion, malocclusion and method of measurements –An overview. Archives of Orofacial Sciences 2007; 2: 3-9.

3. Fabio R, Carlos A, Luciane Q: The impact of malocclusion on adolescents ‘dissatisfaction with dental appearance and oral functions. Angle Orthod 2012; 82:403–9

4 Nobile C, Pavia M, Fortunato L, Angelillo I: Prevalence and factors related to malocclusion and orthodontic treatment need in children and adolescents in Italy. Euro J Public health, 2007; 17(6), 637-41

5. Haralabakis H: Incidence of malocclusion among dental students at Athens University, Trans Europ Orthod Soc 1957: 310-1.

6. Tang E, Stephen H: Recording and measuring malocclusion. A review of the literature. Am J Orthod Dentofac Orthop 1993; 103:344-51.

7. Sarabjeet S, Nidhi B, Navreet S: Incidence of Malocclusions in India – A Review. J Oral Health Comm Dent 2012; 6(1): 21-4.

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

9. Mridula T, Ramesh N, Archana J, Kailash A, Aniruddh T, Sagar J, et al: Prevalence of malocclusion and orthodontic treatment needs among 12?15 years old school children of Udaipur, India.2013;37.236.

10. Guo L, Feng Y, Guo H, Liu B, Zhang Y: Consequences of orthodontic treatment in malocclusion patients: clinical and microbial effects in adults and children. BMC Oral Health, 2016, 28; 16:112.

11. Dimberg L, Lennartsson B, Arnrup K, Bondemark L: Prevalence and change of malocclusions from primary to early permanent dentition: a longitudinal study. Angle Orthod, 2015; 85: 728-734.

12. World Health Organization: Oral health care systems: an International collaborative study. Geneva: WHO; 1985.

13.  Brook P, Shaw W: The development of an index of orthodontic treatment priority. Eur J Orthod, 1989, 11:309-20.

14. Foster T, Day A:  A survey of malocclusion and the need for orthodontic treatment in a Shropshire school population. Br J Orthod. 1974, 1:73-8.

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

16. Proffit W, Fields H Jr, Moray L: Prevalence of malocclusion and orthodontic treatment need in the United States: estimates from the NHANES III survey. Int J Adult Ortho OrthognSurg. 1998; 13:97- 106.

17. Ucuncu N, Ertugay E: The use of Index of Orthodontic Treatment Need (IOTN) in a school population and a referred population. J Orthod; 200,128:45-52.

18. Angle E. Classification of malocclusion. Dent Cosmos 1988; 41:248-64.

19. Abdelkader H, Mohammed R, Ali M: The reliability and validity of the index of complexity, outcome and need (ICON) among sample of Egyptian orthodontic patients. InternJ Clin Dentistry, 2015; 8(2).

20. Alhammadi M, Halboub E, Fayed M, Labib A, El-Saaidi C: Global distribution of malocclusion traits: A systematic review. Dental Press J Orthod 2018, 23(6):40. e1-40. e10.

21. Engh O: Prevalence of malocclusion in schoolchildren (Norwegian). Nor Tannlegeforen Tid. 1970; 80: 622-9

22. Lew K, Foong W, Loh E: Malocclusion prevalence in an ethnic Chinese population. Aust Dent J, 1993, 38: 442-449

23. Brunelle I, Bhat M, Lipton J: Prevalence and distribution of selected occlusal characteristics in the US population, 1988-91. J Dent Res 1996; 75:706-13.

24. Marques L, Pordeus I, Ramos-Jorge M, Filogônio C, Filogônio C, Pereira L, et al. Factors associated with the desire for orthodontic treatment among Brazilian adolescents and their parents. BMC Oral Health. 2009; 9:34.

25.Sarabjeet S, Nidhi B, Navreet S: Incidence of Malocclusions in India – A Review. J Oral Health Comm Dent 2012; 6: 21-4.

26. Trehan M, Chugh V, Sharma S: Prevalence of malocclusion in Jaipur, India. IJCPD 2009; 2:23-5.

27. Siddegowda R, Satish R: The prevalence of malocclusion and its gender distribution among Indian school children: An Epidemiol survey. 2014; 5:4: 224-9.

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

29. Kaul B, Kotwal B, Mahajan N, Kharyal S: Prevalence of Different Types of Malocclusions in the Patients Visiting Government Dental College, Jammu in India Intern J Scientific Study, 2017, 5 :53 -55.

30. Shen L, He F, Zhang C, Jiang H, Wang J: Prevalence of malocclusion in primary dentition in mainland China, 1988–2017: a systematic review and meta-analysis. Scientific Rep, 2018, 8 (4716):1-10.

31. Onyeaso C, Oneyeaso A: Occlusal/dental anomalies found in a random sample of Nigerian school children. Oral Health Prev Dent. 2006; 4:181–6.

32. Mtaya M, Astrom A, Brudvik P: Malocclusion, psycho-social impacts and treatment need: a cross-sectional study of Tanzanian primary school-children. BMC Oral Health. 2008, 6; 33-39.

33. Kapila S: Distribution of malocclusion an African and Asian child in some Nairobi schools. Odont Stompt. Trop., 1983,6:209-214.

34. Abou Affan A, Wisth P, Boe O: Malocclusion in 12-yearold Sudanese Children, Odonto Stomatol Trop., 1990, 13(3):87-93.

35. Alatrach A, Saleh F, Osman E:  The prevalence of malocclusion and orthodontic treatment need in a sample of Syrian children. European Sci J, 2014,10 (30): 1857 – 7881.

36. Merza Hasan S: Prevalence of Malocclusion in Adolescence (12-17 Years) in Najaf area.  J University of Babylon, Pure & Applied Sciences, 2018, 26 (4): 118- 124.

37. Al-Emran S, Wisth P, Boe O: Prevalence of malocclusion and need for orthodontic treatment in Saudi Arabia. Commun Dent Oral Epidemiol. 1990; 18(5):253-5.

38. Krzpow AB, Lieberman MA, Modan M. Prevalence of malocclusion in young adults of various ethnic backgrounds in Israel. J. Dent. Res. 54(3):605-8.

39. El-Hadary M and Aboul-Azm S: (1977): Malocclusion in male young adults. Tanta Med J; 5:337-346.

40. El-Mangoury N, Mostafa Y. Epidemiologic panorama of dental occlusion. Angle Orthod. 1990 Fall; 60(3):207-14.

41. Saif Soliman M, Abd El-Sayed F, Munir H: Prevalence of malocclusion in primary school children of Cairo, Egypt (A Survey Study). E Dental J, 2016, 62: 225:231

42.Abdel Kader W: The prevalence of malocclusion in a group of Egyptian Children. MSc Thesis, Cairo Univ. 1980.

43. Lombardo G, Vena F, Negri P, Pagano S, Barilotti C, Paglia L, et al: Worldwide prevalence of malocclusion  in the different stages of dentition: A systematic review and meta-analysis. European J Pediatric Dentistry 2020;21: 115 – 123.

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

45. Akbari M, Lankarani K, Honarvar B, Tabrizi R, Mirhadi H, Moosazadeh M: Prevalence of malocclusion among  Iranian children: A systematic review and meta-analysis. J Dent 2016; 13(5), 387

46. Sari E, Kurtulmus K, Boyacioglu H: The orthodontic treatment need and malocclusion prevalence in Turkish adult males. Balkan Mili Med Rev, 2007 10:107-13

47. Elham S, Abu Aihaija S, Al-Khateeb N, Al-Nimiry K: Prevalence of malocclusion in 13 – 15 year old north Jordanian school children. Community Dent Health 2005;22: 266 -271.

48. Mevlut Celikoglu  1 , Sema Akpinar, Ibrahim Yavuz: The pattern of malocclusion in a sample of  orthodontic patients from Turkey.  Med Oral Patol Oral Cir Bucal, 2010, 1; 15(5):e791-6.

49.Pascal Tschill,  William  Bacon,  Abdul  Sonko: Malocclusion  in  the  deciduous  dentition  of Caucasian  Children. European J Orthodontics, 1997, 19: 361-7

50. Nazir R, Hussain A, Kaleem M: Oral health status and Malocclusion in flood affected and internally displaced children in Pakistan. Pakistan Oral Dent J, 2012; 32(1).

51. Al-Azemi R, Artun J: Orthodontic treatment need in adolescent Kuwaitis: prevalence, severity and manpower requirements. Med Princ Pract. 2010; 19:348–54.

52. Hedayati Z, Fattahi H, Jahromi S: The use of index of orthodontic treatment need in an Iranian population. J Indian Soc Pedod Prev Dent, 2007;25:10–14.

53. Singh V, Sharma A:  Epidemiology of Malocclusion and Assessment of Orthodontic Treatment Need for Nepalese Children. Intern Schol Res Notices, 2014, Art ID 768357.

54. Celikoglu M, Akpinar S, Yavuz A: The pattern of malocclusion in a sample of orthodontic patients from Turkey. Med  Oral Patol Oral Cir Bucal,2010; 15(5):e791-6