Behavioral and oral health interaction: Evaluating ADHD symptoms, dentofacial anomalies and trauma among mouth breathing children aged 6-12 years

Abstract

Objectives

To determine the prevalence of dentofacial anomalies and the association of dental trauma and symptoms of ADHD as measured by DSM-5 criteria in a cohort of children aged 6–12 years with mouth breathing habit.

Methods

A cross-sectional study based on results of a mouth-breathing test was conducted on 109 consecutively selected children, aged 6-12 years. The children were screened for symptoms suggestive of ADHD based on the Diagnostic and Statistical Manual of Mental Disorders-5 (DSM 5) criteria, and were referred to a pediatrician for a confirmatory final diagnosis of ADHD. Dentofacial anomalies were assessed using the ROMA Index, and the dental trauma was assessed by a single calibrated examiner. Descriptive statistics were reported as frequencies, percentages, means, and standard deviations. Chi-square test was used to assess associations between categorical variables. A p-value of <0.05 was considered statistically significant.

Results

Out of 109 children, 71 were males, and 38 were females. About 46.8 % of mouth breathers showed symptoms of hyperactivity, and 34.9% showed inattention. Class I malocclusion was observed in the majority of participants (84.4%), while 15.6% had Class II malocclusion. A high proportion of children exhibited increased overjet (83.5%) and lip incompetence (83.5%). The prevalence of anterior dental trauma was 15.6%. A significant association was observed between dental trauma and inattention.

Conclusion

The present study demonstrated a high prevalence of dentofacial anomalies and ADHD symptoms among mouth-breathing children, with a statistically significant association between inattention and an increased risk of dental trauma.

1. Introduction

Breathing is a crucial physiological function that develops at birth and, under normal conditions, occurs through the nose. When the child has mixed breathing, that is, nasal breathing supplemented by mouth breathing, it is termed mouth breathing.¹ Mouth breathing can arise from obstruction at any point of the upper respiratory tract, which is directly affected by the size, shape, and position of the surrounding tissues such as the nasal mucosa, adenoids and tonsils, and from pathological changes in the airways.² This leads to disturbance in growth and development of orofacial structures, including the narrowing of the maxilla, underdevelopment of the mandible, protrusion of upper incisors, and alterations in the position of the head and neck.³

Additionally, children breathing through their mouths are more susceptible to upper respiratory infections, halitosis, bruxism, dental trauma, and excessive tooth wear, potentially resulting in improper tooth eruption.² A major risk factor for dental trauma in healthy children is increased overjet, the distance between the upper and lower incisors, which is common in mouth-breathing children. These children often exhibit lip smacking and lip incompetence, further contributing to dental trauma.⁴

According to the American Academy of Child and Adolescent Psychiatry (AACAP), attention deficit hyperactivity disorder (ADHD) is the most common neurodevelopmental disorder in early childhood, characterized primarily by hyperactivity, impulsivity, and inattention. The National Sleep Foundation notes that ADHD often presents with sleep problems, impacting cognitive functions, behavior, and overall daily functioning, which present as hyperactivity, impulsivity, decreased patience, and inattention. Research indicates that children with breathing problems, such as snoring or apnoea, are 40 to 100 times more likely to develop behavioral issues similar to ADHD⁵ and have a higher incidence of dental caries, toothaches, bruxism, bleeding gums, and dental trauma due to hyperactivity and impulsivity, even when medicated.⁶ Hence, the objective of this study was to determine the prevalence of dentofacial anomalies and the association of dental trauma and symptoms of ADHD as measured by DSM-5 criteria in a cohort of children aged 6–12 years with mouth breathing habit. The null hypothesis was that no significant association exists between oral health outcomes and ADHD symptoms among mouth-breathing children aged 6-12 years across the evaluated features.

2. Methods

2.1. Study design and setting

A cross-sectional observational study was conducted over 12 months (January 2022 to December 2022) in the Department of Pediatric and Preventive Dentistry at AJ Institute of Dental Sciences, Mangalore, after obtaining Institutional Ethics Committee (IEC/PEDO22/121/V2) approval. Written informed consent was obtained from the parents/legal guardians of the children participating in the study, and assent was obtained from the children who were able to provide it. The study was conducted in accordance with the World Medical Association's Declaration of Helsinki (Code of Ethics) for research involving human participants.

Prior to the commencement of the study, the principal investigator underwent calibration sessions under the supervision of a senior faculty member from the Department of Pediatric and Preventive Dentistry to standardize the diagnostic procedures for mouth breathing, dentofacial anomalies, and dental trauma assessment. Intra-examiner reliability was assessed using Cohen's kappa statistics (κ = 0.85), and a kappa value of >0.80 was considered acceptable. All clinical examinations and diagnoses were performed by a single calibrated examiner under standardized clinical conditions using mouth mirrors and CPI probes under adequate illumination.

2.2. Sample size estimation and selection

Based on a previous study,⁴ with a prevalence (p) of 44.5%, confidence interval of 95%, and a10% allowable error (e), the estimated sample size was 109, calculated using the formula:

$$n=\frac{Z_{\raisebox{1ex}{$1-\alpha $}\!\left/ \!\raisebox{-1ex}{$2$}\right.}^{2}p\left(1-p\right)}{e^2}$$

Children aged 6-12 years visiting the department for various dental problems during the study period were screened for mouth breathing. A total of 109 children diagnosed with mouth breathing and their caregivers were included in the study.

2.3. Assessment of mouth breathing

The principal investigator (SS) performed the primary diagnosis of mouth breathing using the water-holding test. Parents/caregivers of children who tested positive for mouth breathing were subsequently interviewed using a structured questionnaire after obtaining consent (assent). Children previously diagnosed with a psychiatric or neuropsychiatric disorder were excluded from the study.

2.4. Diagnostic criteria for ADHD

The children participating in the study were initially screened for symptoms suggestive of ADHD based on the Diagnostic and Statistical Manual of Mental Disorders- 5 (DSM-5) criteria.⁷ The DSM-5 criteria include nine symptoms of inattention and nine features of hyperactivity and impulsivity, which are as follows:

2.4.1. Inattention

• a.Lack of attention to details/careless mistakes
• b.Difficulty sustaining attention in tasks
• c.Does not seem to listen when spoken to directly
• d.Does not follow through on instructions
• e.Difficulty organizing tasks and activities
• f.Avoids tasks that require sustained mental effort
• g.Loses or misplaces objects
• h.Easily distracted
• i.Forgetful in daily activities

2.4.2. Hyperactivity and impulsivity

• a.Fidgetiness (hands or feet)/squirms in seat
• b.Leaves seat frequently
• c.Feeling restless
• d.Unable to engage in leisure activities quietly
• e.Always ‘on the go’, difficulty being still for extended time
• f.Talks excessively
• g.Blurts out answers
• h.Difficulty waiting for his or her turn
• i.Interrupts or intrudes on others

Children exhibiting five or more symptoms persisting for more than six months were referred to a pediatrician for confirmation of an ADHD diagnosis. The final diagnosis of ADHD was established by the pediatrician based on the DSM-5 diagnostic criteria.

2.5. Assessment of dentofacial anomalies

Dentofacial anomalies were assessed clinically by the single calibrated examiner (SS) using the ROMA Index – Risk of Malocclusion Assessment Index³ for 7-12-year-old children and the baby-ROMA index for 6-year-old children.⁸

2.6. Assessment of dental trauma

Dental trauma was recorded as ‘present’ or ‘absent’ based on the presence or absence of traumatic dental injury by the single calibrated examiner (SS).

2.7. Statistical analysis

Data were entered into SPSS version 23.0 (IBM Corp., Armonk, NY, USA). Descriptive statistics that include frequency, percentage, mean, and standard deviation (SD) were reported. To assess associations between categorical variables, the Chi-square test (χ²) was used. A p-value of <0.05 was considered statistically significant.

3. Results

A total of 109 mouth-breathing children aged 6-12 years were included in the study, of which 71 (65.1%) were males, and 38 (34.9%) were females. The mean age of the study participants was 9.4 ± 1.8 years. With respect to the ADHD symptoms based on the assessment using DSM-5 criteria, about 46.8 % of mouth breathers showed symptoms of hyperactivity that is associated with behavioral difficulties (hyperactivity scores ≥5), and about 34.9% showed inattention (inattention scores ≥5), with these children being less likely to have difficulties getting along with other children (Table 1). Overall, the findings suggest a considerable prevalence of ADHD-related symptoms among mouth-breathing children in the study population, particularly hyperactivity.

Table 1.

Socio-demographic characteristics, ADHD score, and mean dental caries score among the study population.

Variable
N			109 (100%)
Males			71 (65.1%)
Females			38 (34.9%)
Mean age			9.4 ± 1.8 years
ADHD	Hyperactivity	≤4	58(53.2%)
		≥5	51(46.8%)
	Inattention	≤4	71(65.1%)
		≥5	38(34.9%)

In the dentofacial profile, Class I malocclusion was observed in the majority of participants (84.4%), while 15.6% had Class II malocclusion. A high proportion of children exhibited increased overjet (83.5%) and lip incompetence (83.5%), indicating a higher tendency of dental trauma. Additionally, 73.4% of participants had a convex facial profile, whereas 26.6% presented with a straight profile. The prevalence of anterior dental trauma was 15.6%, with most children (84.4%) having no history of trauma. Overall, the findings indicate that malocclusion patterns characterized by increased overjet and soft tissue imbalance were prevalent in the study population (Table 2).

Table 2.

Frequency distribution table of dentofacial profile and dental trauma in the study population.

Study Variable		Frequency (%)
Malocclusion	Class 1	92(84.4)
	Class 2	17(15.6)
Overjet	Increased	91(83.5)
	Normal	18(16.5)
Lip incompetency	Competent	18(16.5)
	Incompetent	91(83.5)
Facial profile	Convex	80(73.4)
	Straight	29(26.6)
Dental Trauma	Absent	92(84.4)
	Present	17(15.6)

Table 3 shows the association of ADHD-related symptoms and the presence of dental trauma in the study population. Among the children with hyperactivity scores ≤4, about 12.1% had dental trauma compared to 19.6% with scores ≥5. Although the dental trauma prevalence was higher among participants with ≥5 hyperactivity scores, the association was not statistically significant. In contrast, it is observed that the participants with higher inattention scores (≥5) demonstrated a significantly greater prevalence of dental trauma compared to those with lower scores (p < 0.05). These findings suggest that inattention, but not hyperactivity, may be associated with an increased risk of dental trauma.

Table 3.

Association of ADHD-related symptoms and presence of dental trauma in the study population.

		Trauma absent	Trauma present	Chi square value	Sig.
Hyperactivity	≤4	51(87.9)	7(12.1)	1.172	0.303(NS)
	≥5	41(80.4)	10(19.6)
Inattention	≤4	64(90.1)	7(9.9)	5.092	0.030(S)
	≥5	28(73.7)	10(26.3)

4. Discussion

Mouth breathing is a prevalent and detrimental oral habit among children. If not addressed early, it can negatively impact dentofacial development during growth. The consequences of mouth breathing include malocclusion, poor oral hygiene, increased caries incidence, sleep disturbances, behavioral changes, and abnormal maxillofacial growth. Therefore, timely diagnosis and intervention, grounded in a comprehensive understanding of the underlying causes, are crucial.²

The present study evaluated the association between ADHD-related symptoms, dentofacial anomalies, and dental trauma among mouth-breathing children aged 6-12 years. The results of the study demonstrated a high prevalence of hyperactivity and inattention symptoms, along with increased overjet, lip incompetency, and convex facial profile. In addition, a statistically significant association was observed between inattention symptoms and dental trauma.

Breathing through the mouth, a low tongue position, and an elongated anterior facial height are common at 3 years of age but are more often found after age 5. The harmful effects of decreased respiratory function are fully resolved by puberty. Hence, the age group 6-12 years is selected for the present study.⁹ In the current study, the males constituted a majority of the study population with a male-to-female ratio of 2:1. These findings are consistent with those reported by Laurent et al.,¹⁰ indicating a higher prevalence of mouth breathing and ADHD-related symptoms among males compared to females.

Nearly half of the children (46.8%) in the present study demonstrated significant hyperactivity symptoms, while 34.9% demonstrated significant inattention symptoms. These findings may be explained by the chronic airway obstruction and sleep disturbances commonly associated with mouth breathing. Sleep-disordered breathing in children has been associated with reduced attention span, behavioral disturbances, poor scholastic performance, and hyperactive behavior.¹¹

The present study revealed a high prevalence of dentofacial anomalies among mouth-breathing children. About 83.5% of the study participants had an increased overjet and lip incompetency, while 73.4% demonstrated a convex facial profile. These findings are consistent with earlier studies that reported a strong relationship between mouth breathing and altered craniofacial growth patterns.^3,9,12 Zicari et al. reported that mouth breathers frequently demonstrate increased overjet, lip incompetence, posterior crossbite, and Class II skeletal patterns due to altered tongue posture and muscular imbalance.¹² Grippaudo et al. found significant associations between mouth breathing, oral habits, and malocclusion among children.³ The predominance of Class I malocclusion (84.4%) was noted in the present study, while the presence of Class II malocclusion was present in 15.6% of participants. A systematic review by Fraga et al. reported that the prevalence of malocclusion of Angle Class II, division 1, tends to be higher than Class I malocclusion in mouth breathing children.¹³ The high prevalence of lip incompetency, convex profile, and increased overjet observed in the present study further supports the functional matrix theory, which suggests that altered respiratory patterns can influence craniofacial growth and muscle balance. Chronic mouth breathing leads to a low tongue posture, altered perioral muscle activity, and downward mandibular positioning, which eventually contribute to malocclusion and facial disharmony.²

The prevalence of dental trauma in the present study was 15.6%. This finding is clinically important because the majority of children also demonstrated increased overjet and lip incompetency, both of which are risk factors for traumatic dental injuries. Children with protrusive maxillary incisors and inadequate lip coverage are more susceptible to trauma due to reduced protection of the anterior teeth during falls or accidental injuries. The present study demonstrated a statistically significant association between inattention and dental trauma, whereas no such association was observed with hyperactivity. Individuals with higher inattention scores showed a markedly greater prevalence of trauma, which may be explained by underlying behavioral and cognitive factors. Inattention is often characterized by reduced focus, impaired risk perception, and delayed reaction times, which can increase susceptibility to accidental injuries, including dental trauma. Children or individuals with inattention may be less aware of their surroundings and slower to respond to potentially hazardous situations, thereby increasing the likelihood of falls or collisions.

In contrast, although hyperactivity is typically associated with impulsive and risk-taking behavior, the lack of a statistically significant association in this study suggests that hyperactivity alone may not be a consistent predictor of dental trauma. This could be due to variability in environmental supervision, behavioral adaptations, or coping mechanisms that mitigate injury risk. Additionally, the multifactorial nature of dental trauma—including factors such as overjet, lip competence, participation in sports, and socioeconomic influences—may dilute the independent effect of hyperactivity.

Dental professionals and parents need to be aware of the increased susceptibility to oral diseases in children with mouth breathing and ADHD symptoms. The behavioral characteristics of ADHD and their impact on oral health highlight the need for the prevention and management of oral diseases. In this study, there was no significant correlation between dental trauma and mouth breathing; however, dental trauma remains a concern for individuals with ADHD.¹⁴ Common extraoral and intraoral features observed in participants included class I molar relation, convex profile, increased overjet, hypotonic upper lip, and lip incompetency. The findings are similar to those reported by Jefferson Y,¹⁵ indicating that persistent mouth breathing can alter the position of the lips, teeth, and tongue.

Attention Deficit Hyperactivity Disorder is a predisposing factor for dental trauma and soft tissue injuries. There was a major correlation between dental trauma and symptoms of inattention. Child psychiatrists and pediatric dentists need to recognize this aspect of the disorder for early identification, management, and prevention of dental problems. Bridging the knowledge gap between these professions will enhance collaboration and increase care for children with ADHD. According to the study by Kim KM et al.,¹⁶ sleep-disordered breathing (SDB) is significantly associated with behavioral problems in children with ADHD. ADHD is often accompanied by various psychiatric comorbidities, including mood and behavioral disorders such as depression, anxiety, aggression, and substance use issues. The present findings are in agreement with these observations, further supporting the link between SDB and behavioral difficulties in children with ADHD and highlighting sleep disturbances as an important comorbid factor in this group. In our study, 29% of mouth-breathing children met full DSM-5 criteria for ADHD symptoms, which provides an accurate diagnosis of the disorder. This result indicates a strong possibility of misdiagnosing mouth breathing as ADHD due to the similarity in behavioral symptoms. Therefore, identifying and addressing the underlying cause of mouth breathing can help manage the condition effectively.

Children with mouth breathing might be misdiagnosed with ADHD, as mouth breathing may mimic or exacerbate ADHD-like symptoms because of impaired sleep quality and reduced oxygenation during sleep ¹⁷, and hence, consequently treated with medication by a psychiatrist or pediatrician. This could cause long-term effects from medication. Hence, Kalaskar et al.¹⁸ concluded that children with sleep disturbances and ADHD symptoms could be evaluated for mouth breathing before being diagnosed with ADHD.

The present study has certain limitations. Being a cross-sectional study, causal relationships between mouth breathing, ADHD symptoms, and dental trauma could not be established. The diagnosis of ADHD was based initially on DSM-5 screening criteria before pediatric confirmation, which may have introduced subjective bias. Additionally, the study was conducted in a single institution with a relatively limited sample size, thereby limiting generalizability. Longitudinal studies with larger samples and objective behavioral assessments are recommended to further explore the relationships among mouth breathing, neurobehavioral disorders, and dentofacial development.

Despite its limitations, this was the first study to assess the association of ADHD symptoms, dentofacial anomalies, and dental trauma among 6-12 year old mouth breathing children. The present findings highlight the importance of early identification and multidisciplinary management of mouth-breathing children. Early identification and appropriate management of mouth breathing can significantly enhance a child's quality of life, growth, and overall development. Pediatric dentists are often among the first healthcare professionals to identify dentofacial abnormalities and behavioral concerns in children. Early intervention involving pediatric dentists, pediatricians, otorhinolaryngologists, orthodontists, and psychologists may help improve airway function, prevent progression of malocclusion, and reduce the risk of dental trauma and behavioral complications.

5. Conclusion

Mouth breathing in children is associated with dentofacial anomalies and behavioral symptoms suggestive of ADHD, particularly hyperactivity and inattention. The present study demonstrated a high prevalence of increased overjet, lip incompetency, convex facial profile, and ADHD-related symptoms among mouth-breathing children aged 6–12 years. A statistically significant association was observed between inattention symptoms and dental trauma, indicating that behavioral factors may contribute to an increased risk of traumatic dental injuries in this population. Timely diagnosis and intervention, supported by a thorough evaluation of the underlying causes, are essential to prevent the misdiagnosis of ADHD in children affected by mouth breathing.

Ethics approval

This study received ethics approval from Ethics Committee, AJ Institute of Dental Sciences, Mangalore, under the Approval number: (IEC/PEDO22/121/V2)

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.