Malocclusion and occlusal traits among dental and nursing students of Seven North-East states of India

Abstract

Background

Any irregularity of the teeth or a mal-relationship of the dental arches is known as malocclusion. Among all the oro-facial problems, tooth decay is considered the most prevalent one followed by periodontal disease and dental malocclusion. Dental malocclusion is not a life-threatening condition. However, it is closely related to an individual's self-esteem and psychosocial wellbeing. The prevalence of malocclusion varies among different ethnic groups, age-groups, and gender.

Objectives

This study was conducted with the objective to find out the prevalence of normal occlusal traits and to identify the proportion of different types of malocclusions among dental and nursing students of Seven North-Eastern states studying at a tertiary care Medical Institute.

Methods and materials

This cross-sectional study included 432 students with a mean age of 21.42 years, who satisfied the inclusion criteria. Inclusion criteria consisted of the presence of all permanent teeth with or without third molars. The oral cavity was examined using a sterile mouth mirror and flashlight followed by evaluation of all the occlusal relationships in centric occlusion position (COP). COP was achieved by asking the participant to swallow, and then to bite on his or her teeth together. The occlusion traits were assessed as normal occlusion or malocclusion using the first permanent molars as described by E.H. Angle and deviation from line of occlusion. Descriptive statistics like mean and proportions were calculated.

Results

The prevalence of normal occlusal traits was 48.4%, and that of malocclusion was 51.6%. Class I malocclusion was most prevalent occlusal trait followed by Class II malocclusion and Class III malocclusion showed the least prevalence.

Conclusions

Class I malocclusion was most prevalent followed by Class II malocclusion and Class III malocclusion showed the least prevalence.

1. Introduction

Malocclusion is defined as any mal-relationship of dental arches with or without an irregularity of the teeth.¹ Malocclusion is considered as a developmental disorder and a public dental health problem having high prevalence and treatment needs.² Altered oral functions like mastication, speech, swallowing, etc may lead to oro-facial adaptability which may result in malocclusion. This ultimately disturbs the individual's social wellbeing.³ In most of these studies, Angle's classification has been widely used as a qualitative epidemiological tool.^{1, 2, 3} Several studies on the prevalence of occlusal traits in different populations have been reported in the orthodontic literature and such a study on an isolated human population can provide valuable information about the causes of malocclusion.^{2, 3, 4} In many developed countries, where the specialties of Orthodontics and Pedodontics have been well-established, sufficient information on the prevalence of malocclusion is available. However, in developing nations of the world like India, such information is still inadequate.⁵

The criteria to determine the indication of orthodontic treatment is not well understood among the general dentist. So, the general dentist finds it difficult to determine treatment needs and appropriate age of referral to an Orthodontist.⁶ Previous studies suggest that the malocclusion may vary from mild to severe depending on age and ethnicity. Hence, an in-depth understanding of orthodontic problems and treatment needs can help the practicing dentist for diagnosis and appropriate referral.^{7, 8, 9}

Many studies have focused more on the determination of treatment needs, techniques, outcomes, and impact of malocclusion on quality of life. As a result, malocclusion has been considered a public health problem due to its high prevalence and treatment needs.^{10, 11, 12} Some studies have also reported on the relationship of malocclusion with carious tooth or teeth and poor gingival or periodontal health.^13,14

Despite many studies on malocclusion and occlusal traits in different populations,^{2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14} there are no epidemiologic studies specific to the North-Eastern Indian population. The present study was performed to find out the prevalence of normal occlusal traits and different types of malocclusions among dental and nursing students of these states.

2. Subjects and methods

The cross-sectional study comprised of 432 students aged 18–25 years (mean age of 21.42 years) studying in the Dental College and College of Nursing at a tertiary care Medical Institute. All the dental and nursing students from the first year to final year and the interns were included in this study. A total of 500 students were approached. Out of the 500 students approached, 22 students were absent during data collection. Students who were willing to participate in the study were included only after obtaining their written informed consent for voluntarily participation in the study. A total of 432 students, who satisfied the inclusion criteria had participated in this study. Inclusion criteria consisted of the presence of all permanent teeth with or without third molars. Subjects with any history of previous orthodontic or surgical treatment; missing permanent first molars due to extraction and prosthesis were excluded from the study. Those students who do not belong to any of the North Eastern States were also excluded from the study.

Sample size calculation was done using the formula: N = Z² PQ/ L², where Z² = 3.84 (Z is the critical value at 95% confidence level); P = 71% (prevalence of malocclusion in a study by Das et al.)²; Q = 100 – P; L = 4.5 (absolute error) and a non-response rate of 10%. Total sample size was calculated as 432.

The oral cavity of the participants was examined using a sterile mouth mirror and flashlight for their occlusal relationships. The occlusal relationships were determined in Centric Occlusion Position (COP), which was achieved by asking the subject to swallow and then to bite on his or her teeth together. The cheeks were fully retracted using cheek retractors in order to obtain a direct lateral view of the dentition in occlusion on both the right and left side.

The occlusal traits were then determined as Normal occlusal trait or malocclusion using the first permanent molars as described by Angle in 1899.¹ Subjects with Class I molar relationship, normal overbite and overjet, proper alignment, and minimal crowding were classified as Normal occlusal trait. In subjects with Class I malocclusion, Class I molar relations with one or more of these characteristics: crowded incisors or labially positioned canines, or both (Dewey type 1), protruded maxillary incisors (Dewey type 2), edge to edge occlusion of anterior teeth or anterior crossbite or both (Dewey type 3), unilateral or bilateral posterior crossbite (Dewey type 4), a mesial drift of molars (Dewey type 5), anterior or posterior open bite, deep anterior overbite were also examined. Then the prevalence of these features was assessed in participants exhibiting Class I malocclusion. Participants with Class II molar relation with protruded maxillary anterior teeth and large overjet were grouped under Class II Division 1 malocclusion and those with retroclined maxillary central incisors, proclined or normally inclined maxillary lateral incisors, and deep overbite were grouped under Class II Division 2 malocclusion. The occlusion with Class III molar relation with premature contact of incisors or the canines with or without negative overjet was classified as Class III malocclusion.

3. Statistical analysis

The data were collected and entered in excel sheet; which was then checked for consistency and completeness. Descriptive statistics like mean and proportions were calculated. Ethical clearance was obtained from the RIMS Institutional Ethics Committee (reference no. AC/112/EC/RIMS/2015).

4. Results

This study was conducted on 432 students aged 18–25 years (mean age = 21.42 years) who satisfied the inclusion criteria. The prevalence of normal occlusal traits was 48.4%, and that of malocclusion was 51.6%. Among those occlusal traits with malocclusion (51.6%), Angle's Class I malocclusion was found in 36.8%, Class II in 10.4%, and Class III in 4.4% (Table 1). Among the occlusal traits with Angle's Class I malocclusion (36.8%), Dewey's modification type 1 was present in 23.3%, type 2 in 7.4%, and type 3 in 6.0%. (Table 2). Similarly, among Angle's Class II malocclusion (10.4%), the 9.0% were Class II Division 1 and 1.4% were Class II Division 2 (Table 3).

Table 1.

Distribution of malocclusion and normal occlusal traits.

Molar relationship	Frequency	Percent
Class I	159	36.8
Class II	45	10.4
Class III	19	4.4
Normal Occlusion	209	48.4
Total	432	100

Table 2.

Distribution of Dewey's modification of Angle's Class I malocclusion.

Dewey's modification	Frequency	Percent
Type 1	101	23.3
Type 2	32	7.4
Type 3	26	6.0

Table 3.

Distribution of Angle's Class II malocclusion Divisions.

Angle's Class II malocclusion	Frequency	Percent
Division 1	39	9.0
Division 2	6	1.4

5. Discussion

The present cross-sectional study was conducted to assess the prevalence of different forms of malocclusion as described by E.H. Angle.¹ A well-defined sample size of 432 participants with no previous history of orthodontic and surgical treatment was selected for the study, and it was conducted to investigate the orthodontic problems among North-East Indians. This would help to advocate the need for orthodontic treatment in public dental services.^{2, 3, 4, 5, 6}

In our study, Class I malocclusion was present in 36.8%, being the most prevalent and this was found similar to the works of Das et al.² among 745 school children aged 8–12 years (62%); Al Jadidi et al.⁴ among 854 Omami adolescents aged 11–16 years (86.2%); Onyeaso CO⁵ among 636 secondary school students aged 12–17 years in Nigeria (50%); Bilgic et al.⁶ in central Anatolian adolescents (34.9%); Alajlan SS et al.⁷ among 520 school children aged 7–12 years in Northern Saudi Arabia (70.4%). These discrepancies could be due to varying methods and indices, age difference, population size, and examiner subjectivity.^{6, 7, 8}

Among these various occlusal traits of Class I malocclusion, Dewey's modification of Angle Class I type 1 (crowding) was present in 23.3%, type 2 (proclination) in 7.4%, and type 3 (anterior crossbite) in 6.0% in the present study. Das et al.² also found anterior crowding as the most common finding and mesial drift of molars as the least common. In the study of Omami's adolescents, severe crowding was present in 2.3%, severe proclination in 8.6%, posterior crossbite in 6.8%, and no anterior crossbite, unlike the present study.⁴ In another study among Ibo ethnic group, they found 20% crowding, and 16% proclination, but no crossbites.⁵ This study supported our study as crowding was most prevalent among the variables of Class I malocclusion as mentioned previously. Similarly, a study by Bilgic et al.⁶ also found crowding (66.2%) as most prevalent among the variables, 25.1% proclination, 10.4% anterior crossbites, and only 0.3% posterior crossbite. Alajlan et al.⁷ reported no crowding, but proclination in 14.4%, anterior crossbite in 5.2%, and posterior crossbite in 4%.

In the present study, Class II Division 1 was 9.0%, and Class II Division 2 was 1.4%. Das et al.² also reported 6.8% Class II Division 1, and 1.6% Class II Division 2. Al Jadidi et al.⁴ in Omami adolescents also found 11% of the sample having Class II Division 1 incisors relationship, and only 1.8% had Class II Division 2 incisors relationship supporting the present study. Similarly, a study by Bilgic et al.⁶ also reported 40% Class II Division 1, and only 4.7% Class II Division 2.

In the present study, the Class III molar relationship was recorded in 4.4% which was least prevalent of all the malocclusion forms. Other studies had also reported Class III malocclusion as least prevalent such as Das et al.² found 0.6% Class III malocclusion as least prevalent; Al Jadidi et al.⁴ in Omami adolescents found 13.5% Class III malocclusion; 12% among Ibo ethnic group by Onyeaso⁵; Bilgic et al.⁶ reported 10.3% Class III malocclusion; Alajlan et al.⁷ reported 7.7%; Mtaya et al.¹³ found only 2% among Tanzanian school children and Yu et al.¹⁴ found 5.9% in Shanghai city.

A study of Asian male adults by Soh et al.¹⁵ found Angle's Class I molar relationship as the most prevalent (48.1%) supporting the present study, and Class II Division 2 relationship was the least prevalent (3.2%), unlike the present study. Anterior crowding was a common occlusal feature for both the studies.

In the previous study performed by Lagana et al.,¹⁶ Class I, Class II, and Class III malocclusion and asymmetries observed were 40.4%, 29.2%, 3.2%, and 27.1% respectively. Similarly, in the present study, Class I was 36.8%, Class II was 10.4%, Class III was 4.4% showing Class I malocclusion most prevalent, and Class III malocclusion least prevalent.

In another study with a total of 241 Brazilian school children from 20 schools in Juiz de Fora, Brazil by Gois et al.,¹⁷ the prevalence of normal occlusion was 8.5% and that of malocclusion was 91.5%. However, in the present study, the prevalence of normal occlusion was 48.4%, and that of malocclusion was 51.6%.

In a previous study carried out by Damle et al.¹⁸ among 12–15 years old children in rural and backward areas of Haryana, 76.4% of children had little or no malocclusion and 23.6% of children needed treatment. Unlike in the present study, 51.6% of the population showed the presence of different forms of malocclusion, while Normal occlusion was 48.4%.

In a quantitative study performed by Shrestha et al.¹⁹ to find the prevalence of malocclusion among medical students in the institute of medicine, Nepal, the prevalence of normal occlusion was 9.6%. However, in the present study, the percentage of normal occlusion was 48.4%. But malocclusion was found in 51.6% in which Class I malocclusion was most prevalent followed by Class II malocclusion and Class III malocclusion.

Kharbanda et al.²⁰ performed a study on the prevalence of malocclusion among children aged 10–13 years of Delhi where 44.5% malocclusion (26% Class I malocclusion, 15% Class II malocclusion, and 3.5% Class III malocclusion) was reported. Similarly, our study also reported 36.8% Class I malocclusion, 10.4% Class II malocclusion, and 4.4% Class III malocclusion. In another study by Singh et al.²¹ among rural children in Haryana aged 12–16 years, the prevalence of malocclusion was 55% supporting the present study with 51.6% prevalence of malocclusion.

A study by Kaul et al.²² in Jammu found the prevalence of malocclusion in 83% of the subjects (13–14 years old) which included Class I malocclusion in 67%, Class II Division 1 in 8%, Class II Division 2 in 6%, and Class III in 2% only. In another study in the Dravidian population, Sundareswaran et al.²³ reported an overall prevalence of malocclusion in 89.9% comprised of Angle's Class I (74.4%), Class II (17.6%), Class III (8%), and other anomalies in 7.2% among 13–15 years old school children of Calicut district, Kerala. The above two studies supported the present study.

This evaluation of prevalence among the population could provide objective information about the malocclusion. Hence, this information could be used to create effective public dental health plans for orthodontic prevention and better screening in the North-Eastern region of India. It might also help to indicate the need for orthodontic treatment to improve public dental health.

6. Conclusions

The prevalence of normal occlusal traits was 48.4% and that of malocclusion was 51.6% among the dental and nursing students of the North-Eastern region of India. Class I malocclusion was most prevalent occlusal trait (36.8%) followed by Class II malocclusion (10.4%) and Class III malocclusion (4.4%) being the least prevalent. Anterior crowding was the most common feature associated with Class I malocclusion.