Impact of Oral Habits on Malocclusion in Pediatric Dental Patients: A Dental Educational Institute-based Cross-sectional Observational Study

Abstract

Background

Oral habits are repetitive actions involving the oral cavity that can impact dental development. Persistent habits beyond the usual age have been considered deleterious and are likely to affect the development of the craniofacial complex adversely. Among the potential consequences, malocclusion stands out as a prevalent issue. This study seeks to evaluate the relationship between oral habits and malocclusion, enhancing treatment and prevention strategies.

Objective

To assess the prevalence of oral habits and malocclusion and to identify the differences in treatment needs between those with and without oral habits.

Materials and methods

An observational, cross-sectional study was conducted over 6 months at a dental educational institute. A prevalidated questionnaire was used to collect history from parents of pediatric dental patients regarding oral habits (tongue thrusting, mouth breathing, and thumb-sucking). In children with positive histories, the habit's presence was confirmed through clinical assessment and diagnostic tests. Malocclusion diagnosis and severity assessment were done following Federation Dentaire Internationale guidelines and using the Index of Orthodontic Treatment Need (IOTN), respectively. Collected data were analyzed statistically with SPSS version 21 for Windows (SPSS Inc., Chicago, Illinois).

Results

The prevalence of deleterious habits and malocclusion among the studied sample was 13.2% and 46.2%, respectively. All children (100%) with oral habits (group H) showed malocclusion, while only 46.8% of those without habits (group N) did. IOTN scores significantly differ between groups H and N, showing greater treatment needs in children with habits (p = 0.000). Objective treatment needs (grades V and IV) occurred in 31.6% of children with habits and 2.4% without. Borderline needs (grade III) were noted in 47.4% of children with habits, compared to 2% without. A total of 10.5% of children with habits and 8.7% without reported little need (grade II). Only 10.5% of those with habits and 33.7% without showed no need (grade I).

Conclusion

Within the study's limitations, a higher prevalence of malocclusion with more significant treatment needs is observed in children with deleterious oral habits compared with children who had no habits. Thus, we can assume that environmental factors can play a vast role in the development of malocclusion.

How to cite this article

Satti AS, Samudrala P, Sankar AJS, et al. Impact of Oral Habits on Malocclusion in Pediatric Dental Patients: A Dental Educational Institute-based Cross-sectional Observational Study. Int J Clin Pediatr Dent 2025;18(12):1483–1488.

Introduction

Malocclusion is a noticeable departure from the optimum occlusion that could be deemed unacceptable from an esthetic or functional standpoint.¹ According to the WHO, malocclusion is the third most prevalent oral disease after caries and periodontal disease.^2,3 Occlusion is currently considered a dynamic concept and is conditioned by several factors under genetic and environmental influence.⁴ So, malocclusions are typically multifactorial in origin, determined by genetic and environmental influences.⁵

Genetics governs the inheritance of morphological traits such as the size and shape of the jaw, arch, and teeth, while environmental factors contribute to a complex interplay that influences skeletal relationships.^2,6 In recent years, the recognition that many malocclusions arise postnatally has led to a diminished emphasis on genetic factors as the primary etiology.⁵

Teeth are considered a closed system, as their size and shape are genetically predetermined. In contrast, the supporting bone is regarded as an open system, as its growth is influenced by external stimuli such as oral functions and habits.^4,7 Oral habits are broadly categorized into physiological and deleterious habits.⁸ Physiological habits arise from repeated normal functions appropriate for a given age and serve as stimuli for proper jaw growth (e.g., speech, swallowing, and chewing). Conversely, habits that deviate from normal practices or persist beyond the typical developmental age are classified as deleterious habits.⁹ Examples of such habits include thumb-sucking, mouth breathing, and tongue thrusting. Prolonged engagement in deleterious habits can disrupt the balance of oral musculature forces and interfere with dental alignment. As a result, these habits have been identified as significant environmental factors contributing to the development of malocclusion.^2,9

The tongue is a primarily muscular organ that fills the functional area of the mouth and assumes a balancing and compensatory function against the forces of the lips, cheeks, and air pressure in the nasal cavity, having an essential impact on forming the arches and the maxillary complex's development. Of all the deleterious habits, tongue thrusting, mouth breathing, and thumb-sucking are majorly related to the position of the tongue.¹⁰ Preventing these oral habits can reduce the prevalence of malocclusions in the community.

Therefore, this study aims to explore and evaluate the prevalence of oral habits (tongue thrusting, mouth breathing, and thumb-sucking) and their relationship with malocclusion by identifying differences in treatment needs between individuals with and without these habits.

Materials and Methods

A cross-sectional study was conducted among pediatric patients seeking dental treatment at a dental institute over a 6-month period (September, 2024–February, 2025). The study protocol was approved by the Institutional Ethics Committee of Sibar Institute of Dental Sciences (Ref. No. 11/IEC-SIBAR/CIR/23) and adhered to the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines for cross-sectional studies to ensure methodological rigor and transparency. The sample was collected using a nonprobability consecutive sampling technique. Medically fit children without any congenital disorders or syndromes and with no previous history of orthodontic treatment were included in the study. Children requiring emergency treatment, those with severe dental caries or periodontal disease, and those with missing central permanent or deciduous incisors (as IOTN cannot be recorded) were excluded.

Clinical Data Collection

After obtaining approval from the institutional ethical committee, the study protocol was thoroughly explained to parents and children and informed consent was obtained. A prevalidated structured questionnaire was used to gather information from parents about signs, symptoms, frequency, and duration of specific harmful oral habits, including tongue thrusting, mouth breathing, and thumb-sucking.

In children with a positive history, the presence of habit was confirmed through clinical assessment and specific chairside diagnostic tests. All clinical examinations were made by the same investigator in the clinical setting. Fingers involved in digit-sucking were inspected to see if they were wet or wrinkled, had callosities, had irritative eczema, or had paronychia in the thumb or index finger. The patient was asked to take a sip of water and swallow to evaluate tongue thrusting. In this process, the patient was observed for the following: grimacing, the contraction of the orbicularis muscles of the lips, masseter of the jaw, water leakage, or if there is the interposition of the tongue between the incisors when swallowing. Water-holding, double-mirror, and butterfly tests were performed to recognize the type of breathing (nasal or oral).⁹ Study participants were divided into groups H and N based on the presence or absence of deleterious oral habits.

Intraoral examination for malocclusion characteristics (increased overjet, open bite, deep bite, posterior crossbite, anterior crossbite, spacing, and crowding) was performed according to the principles developed by the Federation Dentaire Internationale using a mouth mirror and metric ruler.¹¹ The severity of the malocclusion was assessed using IOTN (Index of Orthodontic Treatment Need), based on scoring criteria given by Brook and Shaw.¹² All the findings were recorded in a case study form. The collected data were tabulated and subjected to statistical analysis using Statistical Product and Service Solutions (SPSS) version 21 for Windows (SPSS Inc., Chicago, Illinois). The Chi-square test was used to find the association between parafunctional oral habits, IOTN scores, and different malocclusion traits. An intragroup comparison of IOTN scores was done between groups H and N.

Results

Between September, 2024 and February, 2025, 1,404 children were reported, of whom 244 were excluded based on the exclusion criteria and their refusal to participate. Thus, 1,160 patients, with a mean age of 10.76 ± 1.9 years, were included in this study, with 45.5% being female and 53.5% being male.

The prevalence of deleterious habits and malocclusion among the studied sample was 13.2 and 46.2%, respectively. Among the 13.2% of the population with oral habits, 50% practiced mouth breathing, followed by tongue thrusting (21.05%) and thumb-sucking (10.5%). Additionally, 18.1% of children engaged in more than one habit (Fig. 1).

Fig. 1:

Frequency distribution of deleterious oral habits

All children (100%) with oral habits (group H) exhibited malocclusion of varying degrees of severity, whereas only 46.8% of children without habits (group N) showed malocclusion. Table 1 and Figure 2 illustrate the prevalence rates of the IOTN scores in groups H and N, indicating significantly greater treatment needs in children with habits (p = 0.000). An objective treatment need (grades V and IV) was recorded in 31.6% of children with habits and 2.4% of those without habits. A borderline need (grade III) was observed in 47.4% of subjects with habits, compared to only 2% in children without. A total of 10.5% of children with habits and 8.7% of those without reported little need for orthodontic treatment (grade II) habits. Only 10.5% of subjects with habits and 33.7% of those without presented no need for orthodontic treatment (grade I).

Table 1:

Prevalence rates of IOTN scores in groups H and N showing there is a significant increase in scores of group H

IOTN	Group H (with habits) N (%)	Group N (without habits) N (%)	χ2value	p-value
Score 0	0 (0%)	536 (53.1%)	163.93	0.000*
Score 1	16 (10.5%)	340 (33.7%)
Score 2	16 (10.5%)	88 (8.7%)
Score 3	72 (47.4%)	20 (2.0%)
Score 4	40 (26.3%)	16 (1.6%)
Score 5	8 (5.3%)	8 (0.8%)

Chi-square test; *p ≤ 0.05 is considered as statistically significant

Fig. 2:

Distribution of IOTN scores among participants with and without habits

Table 2 depicts the association of parafunctional oral habits with various malocclusion traits, using the Chi-square test for statistical significance. Among all the tested malocclusion traits, mouth breathing was significantly associated with crowding (p = 0.008), and tongue thrusting was substantially related to open bite (p = 0.004) and spacing (p = 0.001). At the same time, thumb-sucking was significantly linked to open bite (p = 0.012) and posterior crossbite (p = 0.040).

Table 2:

Association of parafunctional oral habits with malocclusion traits using Chi-square test

Malocclusion traits	Mouth breathing			Tongue thrusting			Thumb-sucking
	N (%)	χ2value	p-value	N (%)	χ2value	p-value	N (%)	χ2value	p-value
↑ Overjet	44 (68%)	0.156	0.690	68 (44%)	0.627	0.429	12 (612%)	0.086	0.770
Open bite	16 (33.3%)	2.611	0.106	28 (58.3%)	8.209	0.004*	16 (33.3%)	6.248	0.012*
Deep bite	20 (71.4%)	0.121	0.728	8 (28.5%)	0.427	0.514	0 (0%)	1.30	0.254
Posterior crossbite	20 (55.5%)	0.549	0.459	16 (44.4%)	0.122	0.727	12 (33.3%)	4.201	0.040*
Anterior crossbite	8 (66.6%)	0.001	0.973	8 (66.6%)	1.008	0.315	0 (0%)	0.494	0.482
Spacing	16 (44.4%)	2.387	0.122	32 (88.8%)	12.053	0.001*	4 (11.1%)	0.043	0.835
Crowding	10 (100%)	7.057	0.008*	3 (30%)	0.510	0.475	0 (0%)	2.056	0.152

Chi-square test; *p ≤ 0.05 is considered as statistically significant

Discussion

Parafunctional oral habits refer to unintentional, repetitive muscle contractions in the orofacial region. These behaviors are learned automatisms, often performed subconsciously, and may include habits such as thumb-sucking, tongue thrusting, lip biting, or bruxism. While these habits are common in children, they do not always pose a risk to the stomatognathic system (the complex structure comprising the teeth, jaws, and associated muscles) if they remain within physiological limits. In such cases, these behaviors may be considered harmless and part of normal developmental phases.⁷

However, when parafunctional oral habits persist beyond acceptable limits, they can lead to significant oral health issues. Over time, these behaviors disrupt the natural equilibrium between internal and external muscular forces in the orofacial region, potentially leading to dental and skeletal anomalies such as malocclusion. For example, prolonged thumb-sucking may result in an anterior open bite, while chronic tongue thrusting can contribute to dental misalignment or abnormal spacing. These effects are compounded when the habits are frequent, intense, or persist long, highlighting their potential for long-term harm.¹³

The importance of early diagnosis and intervention in managing these parafunctional habits cannot be overstated. Dentists play a critical role in identifying early signs of these behaviors and educating parents about their potential long-term consequences. Timely detection enables the implementation of corrective strategies such as behavioral modification techniques, orthodontic interventions, or habit-breaking appliances, which can reduce the risk of irreversible harm. Parental involvement is equally important, as consistent monitoring and guidance help discourage these habits. Proactive management not only enhances the likelihood of restoring proper stomatognathic function and balance but also prevents malocclusion, promoting overall dental health and well-being in children.^8,13

This study evaluated 1,160 pediatric dental patients for deleterious oral habits, identifying a prevalence rate of 13.2%. These findings align with previous studies by Jindal et al. (18%) and Hegde and Xavier (19.95%) conducted in the Modinagar and South Kanara districts, respectively.^13,14 In comparison, Guaba et al. found a substantially lower prevalence of 3% in the rural children of Haryana.¹⁵ Comparative international studies demonstrated markedly higher prevalence rates: Laganà et al. (Albania, 80.6%), Alanazi et al. (Saudi Arabia, 79.2%), and Amir et al. (Pakistan, 51%).^16–18 These discrepancies can be attributed to diagnostic criteria, socioeconomic statuses, racial variation, and the selection of different oral habits.

The study participants had a mean age of 10.76 ± 1.9 years (range: 7–14 years). The highest prevalence of oral habits (33%) occurred in 7-year-olds, followed by a sharp decline with nonsignificant variations among older age groups: 9.30% (8-year-olds), 15.10% (9-year-olds), 12.10% (10-year-olds), 12.5% (11-year-olds), 12.9% (12-year-olds), 16.20% (13-year-olds), and 9.09% (14-year-olds). These findings align with Jindal et al.'s report of decreasing prevalence during late childhood in Modinagar, India.¹³ In contrast, Bosnjak et al. in Zagreb, Croatia, documented an initial increase with age followed by a slight decline in the oldest cohort.¹⁹ Studies focusing on younger children (3–5 years) revealed higher prevalence rates: Rai et al. (42.7%, Nepal), Chour et al. (47.2%, Davanagere), Aktaş et al. (40.7%, Turkey), and Dhull et al. (36%, Bhubaneswar).^20–23 Bishara et al. similarly noted a progressive decline in habit prevalence after age 7–8 years.²⁴ Collectively, these studies demonstrate a consistent pattern of decreasing oral habit prevalence from early childhood through adolescence.

Oral habits may peak during early and middle childhood (4–10 years), likely due to increased stress, competitiveness, and parental expectations during the early school years. Habits in late childhood are often characterized by the continuation of habits formed during early childhood, with some habits potentially persisting due to a lack of early intervention or reinforcement of comfort behaviors.

In the current study, among the 13.2% of participants exhibiting oral habits, the most prevalent was mouth breathing (50%), followed by tongue thrusting (21.05%) and thumb-sucking (10.5%). An 18.1% of children are engaged in more than one habit. These findings align with Motta et al., who reported mouth breathing as the most prevalent habit (49%) followed by biting/sucking on objects (33.3%).²⁵ Similarly, Jindal et al. found that mouth breathing was the most prevalent (6.4%) among other habits.¹³

However, comparative studies reveal significant variations: Ganapathi et al. identified lip biting (32.91%) and tongue thrusting (26.58%) as most prevalent, with mouth breathing accounting for only 15.82%.²⁶ Similarly, Surana et al. reported thumb-sucking as the predominant habit (42%), contrasting sharply with our findings.²⁷ Conversely, lower thumb-sucking prevalence was documented by Hegde and Xavier (1.9%) and Sharma et al. (0%), consistent with our observations.^14,28

Malocclusion is said to be caused by genetic and environmental factors. For decades, many have argued over their roles in the etiology of malocclusion.⁶ Recent evidence suggests environmental factors may play a more significant etiological role, given that many malocclusions have a postnatal origin.⁵ Kawala et al.'s twin study demonstrated clear environmental influences on malocclusion development, challenging the predominance of genetic factors in current paradigms.⁶ Oral habits are believed to be among the most apparent examples of malocclusion's environmental etiology, as these habits disrupt muscular balance and bone growth, producing changes in the dental arch and occlusal characteristics.²⁹

In our current study, the prevalence of malocclusion is 100% in children with deleterious oral habits, compared to only 46.8% in habit-free children. Using the Dental Health Component (DHC) of the IOTN to assess severity, we found significantly greater treatment needs among children with oral habits (p = 0.000). Notably, 31.6% of children were with objective treatment needs (IOTN grades IV–V) vs just 2.4% of controls. Borderline need (grade III) was observed in 47.4% of habit-positive children compared to 2% of habit-negative children. Minimal orthodontic treatment need (grade II) was reported in 10.5 and 8.7% of children with and without habits, respectively. Only 10.5% of children with oral habits demonstrated no orthodontic treatment need (grade I), contrasting with 33.7% of unaffected children.

The current findings, which demonstrate increased malocclusion severity among children with oral habits, align with previous research. Pruthi et al. established a significant association between deleterious oral habits and higher Dental Esthetic Index (DAI) scores, indicating that children with such habits exhibit greater malocclusion severity.⁵ Similarly, Grippaudo et al. employed the Risk of Malocclusion Assessment Index (ROMA) to quantitatively assess the relationship between malocclusion severity and deleterious oral habits, with a particular focus on mouth breathing. Their analysis revealed a positive correlation between the prevalence of detrimental oral habits and ROMA index scores, further supporting the significant association between these parafunctional behaviors and severe malocclusion.³⁰

This correlation highlights how parafunctional behaviors—such as thumb-sucking, tongue thrusting, or mouth breathing contribute to progressive dental misalignment and compromised occlusal esthetics. These habits, when persistent, exert undue biomechanical forces on the developing dentition and surrounding structures, leading to more pronounced malocclusive manifestations. These studies collectively reinforce the critical need for early identification and management of parafunctional behaviors to mitigate their adverse effects on oral health.

In contrast, a study involving Nigerian schoolchildren presents a differing perspective. Kolawole et al. reported lower mean Dental Esthetic Index (DAI) scores and a reduced need for orthodontic treatment among children with oral habits, suggesting less severe malocclusion in this population.³¹ This discrepancy may stem from variations in the prevalence, duration, frequency, and intensity of oral habits. For instance, a lower prevalence of harmful habits, along with less intense or sustained engagement in these behaviors, could contribute to the observed reduction in malocclusion severity. Additionally, environmental, cultural, and genetic factors may influence these outcomes, highlighting the need for further research to elucidate their potential protective effects.

These contrasting findings highlight the multifactorial nature of malocclusion severity. While oral habits represent a significant contributing factor, their impact appears modulated by individual susceptibility, environmental influences, and potential genetic predisposition. This variability highlights the importance of tailored approaches in assessing and addressing malocclusion, considering different populations' unique needs and circumstances.²⁹

This study focuses on habits such as tongue thrusting, mouth breathing, and thumb-sucking, due to their established association with aberrant tongue posture. Proper tongue positioning is critical for maintaining equilibrium among the forces exerted by the lips, cheeks, and nasal air pressure, all of which significantly influence arch development. These habits promote low tongue posture, which disrupts normal occlusal development through two primary mechanisms: (1) Reduced palatal thrust from the tongue, and (2) consequent downward rotation and anterior displacement of the mandible.¹⁰ The malocclusion traits evaluated in this study were exaggerated overjet, reverse overjet, open bite, deep bite, posterior crossbite, spacing, and crowding.

In the present study, exaggerated overjet emerged as the most prevalent malocclusion trait among children with deleterious oral habits. Similar studies done among 6–13-year-olds, Kolawole et al. found spacing, crowding, and increased overjet, and Zakirulla et al. found spacing and crowding as the most common malocclusion traits among children with deleterious oral habits.^31,32

Chi-square analysis revealed significant associations between specific deleterious oral habits and malocclusion traits. Mouth breathing demonstrated a strong association with dental crowding (p = 0.008). Similarly, tongue thrusting showed significant correlations with both open bite (p = 0.004) and spacing (p = 0.001). Thumb-sucking was significantly associated with open bite (p = 0.012) and posterior crossbite (p = 0.040). In a similar study conducted by Santos Barrera et al., it was determined that there is a statistically significant relationship between (1) open bite (vertical plane) and immature swallowing patterns and (2) posterior crossbite (horizontal plane) with oral breathing, atypical swallowing, and digital sucking.³³ Furthermore, Al-Atabi observed significantly higher prevalence rates of increased overjet, open bite, posterior crossbite, spacing, and crowding among children with deleterious oral habits compared to those without such habits.³⁴

There are some limitations to this study. First, our sample comprised children seeking dental treatment at a single institute, which may limit generalizability to the broader population. Therefore, further research with a larger and more diverse sample is necessary to generalize the findings to the broader population of the region. As a cross-sectional study, it captures data at a single point in time, and longitudinal studies would be better suited to explore the progression of habits. Furthermore, the habits' duration, intensity, and frequency should be analyzed to learn more about the habit's severity. Only the mere presence or absence of habit was recorded.

Conclusion

Within the study's limitations, a higher prevalence of malocclusion with greater objective treatment needs was observed in children with deleterious oral habits compared to those without such habits. Thus, it can be inferred that environmental factors may play a significant role in the development of malocclusion. This emphasizes the importance of early identification and intervention for deleterious oral habits to mitigate their impact on malocclusion, offering a basis for targeted preventive and therapeutic strategies to improve oral health outcomes in children.

Clinical Significance

This study emphasizes the role of environmental factors, particularly oral habits, in developing malocclusion. It highlights the importance of early identification and intervention to prevent or mitigate the severity of malocclusion, thereby reducing the need for extensive orthodontic treatment later in life. The findings support the implementation of tailored treatment plans, preventive strategies, and targeted parental education to address deleterious oral habits effectively.

Orcid

Asha Sai Satti https://orcid.org/0009-0003-1841-5861

A J Sai Sankar https://orcid.org/0000-0002-6233-6963

Bhargavi Kota https://orcid.org/0009-0005-5854-7548

Deepthi N Gavarraju https://orcid.org/0000-0001-9506-7889

Chaitanya Mohan Sattenapalli https://orcid.org/0000-0003-2271-658X