Introduction
Children with attention deficit hyperactivity disorder (ADHD) have more sleep breathing problems and parafunctional oral habits than individuals without ADHD. However, there is scarce information on the correlation between their dental malocclusion and these functional disorders. The objective of this study was to assess the severity of malocclusion in patients with and without ADHD and to evaluate the correlation between their functional disorders and dental malocclusion.
Methods
Eighty-eight patients aged 6-17 years were divided into 2 groups: ADHD (n = 44) and control (n = 44). A medical questionnaire to assess functional disorders and an orthodontic examination to evaluate malocclusion were completed for each patient. Distribution of the data was evaluated using Shapiro-Wilk test, whereas the 2 groups were compared with a t test, Mann-Whitney U test, Fisher exact test, and Spearman correlation. The association between parafunctional oral habits, ADHD drug intake, and malocclusion severity were assessed with a t test and Mann-Whitney U test.
Results
Patients with ADHD had significantly higher severity of malocclusion ( P = 0.042), more dental rotation ( P = 0.021) and more parafunctional oral habits ( P = 0.001), specifically bruxism ( P = 0.005), and a history of pacifier use ( P = 0.009), than the control group.
Conclusions
It is important to be aware of the increased risk of parafunctional oral habits and dental malocclusion among ADHD patients to develop preventive programs, as well as therapeutic strategies for them.
Highlights
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We assessed malocclusion in children with attention deficit hyperactivity disorder.
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Children with ADHD have a higher severity of dental malocclusion.
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Children with ADHD present more dental rotation.
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Children with ADHD have more parafunctional oral habits.
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Children with ADHD present more bruxism and pacifier use during infancy.
Attention deficit hyperactivity disorder (ADHD) is a neurological disorder characterized by inattention, hyperactivity, and impulsivity. It affects approximately 4% of children worldwide, and boys are 3 times more affected than girls. Its etiology is multifactorial, including genetic, cerebral, psychologic, and environmental factors.
Evidence has shown that children with ADHD present more anxiety toward dental treatment. Those patients are also more at risk of developing dental caries, dental attrition, and parafunctional oral habits, such as bruxism, nail biting, and cheek biting. , Furthermore, a reduced history of breastfeeding during infancy and more sleep breathing disorders have been reported in this population. Although these factors can be related to dental malocclusion, it is still unclear whether the prevalence of malocclusion and the need for orthodontic treatment are higher in children with ADHD. ,
Few studies have looked at the prevalence and severity of malocclusion in children with ADHD. In addition, none of them carried out a complete assessment of occlusion or used a validated malocclusion assessment index. Although a few studies have found no difference in malocclusion in children with ADHD when compared with a control group, others have reported more deep palate and less mesomorph face type in this population.
Considering that malocclusion can lead to a wide range of functional, esthetic, and psychosocial problems and may also impair children’s quality of life, knowledge of its prevalence and severity in children with ADHD is valuable in early diagnosis and treatment planning. Thus, this study aimed to determine the prevalence and severity of malocclusion in children with ADHD and to estimate the association between malocclusion and the presence of a functional disorder among this population.
Material and methods
This cross-sectional study was carried out at the Orthodontic Clinic of the Université de Montréal and the Division of Dentistry of the Montreal Children’s Hospital in Quebec, Canada. The study received ethics approval from the ethics committees of both participating institutions, and informed consent was provided by all children and their parents.
Children aged between 6 and 17 years with a medical diagnosis of ADHD were included in this study. Eligible children were those in mixed or permanent dentition and with no other underlying medical condition. Each child with ADHD was matched with a healthy child (control) with the same demographic characteristics (sex and year of birth). The eligibility criteria of the control group were the same as that of the ADHD group. Children with previous orthodontic treatment were excluded.
The sample size estimation was based on a difference of 5 units and a standard deviation of 8 units in the Dental Aesthetic Index (DAI) between the 2 groups. Using a 2-tailed independent-samples t test (α = 0.05) and a power of 80%, we determined that 84 patients, 42 in each group, were required for this study.
Measures included an orthodontic examination and a questionnaire. All children were clinically examined by 3 licensed resident dentists from the Division of Dentistry (Montreal Children’s Hospital) and by 1 resident of the Orthodontic Clinic of the Université de Montréal. Before initiating data collection, the resident dentists were trained and calibrated, and a reliability test was conducted to ensure the accuracy of the results obtained. The DAI was used to measure the severity of malocclusion and need for orthodontic treatment among the study population. The DAI is an occlusal index designed to categorize malocclusion into groups according to the level and priority of orthodontic treatment required. This index involves evaluating parameters of dentofacial anomalies as follows: (1) missing teeth, (2) crowding, (3) spacing, (4) interincisal diastema, (5) largest maxillary irregularity, (6) largest mandibular irregularity, (7) overjet, (8) overbite, (9) anterior open bite, and (10) anteroposterior molar relationship (Angle classification). Each DAI component has a specific regression coefficient to yield the DAI score. In this study, we also evaluated the children’s labial incompetence, hyperactivity of the mentalis muscle, significant rotations, deviation of the dental midlines, dental anomalies, curve of Spee, Monson’s sphere, and curve of Wilson. The children’s oral habits, including nail biting, bruxism, clenching, and nonnutritive sucking habits (pacifier use and finger sucking), were also recorded.
The questionnaire assessed the children’s demographic characteristics, such as age, sex, and ADHD diagnosis. For each child with ADHD, all prescriptions for medications, as well as the duration of use and dosage, were noted. The children’s history of breastfeeding, type of breathing (nasal, mouth breathing, or both) and the presence of sleep-disordered breathing, such as sleep apnea, were also recorded.
Statistical analysis
Interrater reliability was calculated using the intraclass correlation coefficient. Distribution of the data was evaluated with Shapiro-Wilk test, whereas the 2 groups were compared with the independent-samples t test, Mann-Whitney U test, and Fisher exact test. Finally, the association between parafunctional oral habits, ADHD drug intake, and malocclusion severity in the experimental group were assessed with the independent-samples t test, Mann-Whitney U test, Fisher exact test, and Spearman correlation. All data analyses were performed using SPSS software (version 25; IBM Corp, Armonk, NY). A P value <0.05 was considered to be statistically significant.
Results
Interrater reliability for the DAI calculated with the intraclass correlation coefficient was 0.818, which was considered as excellent for this study. A total of 88 patients were included in this study, and the sample was equally divided between the 2 groups: ADHD group (n = 44) and control group (n = 44). Characteristics of study participants are shown in Table I . Seventy percent of the participants in both groups were male, and the mean age was 11 years.
| Variable | ADHD, n = 44 | Control, n = 44 | P value ∗ |
|---|---|---|---|
| Sex | 1.000 | ||
| Male | 31 (70.5) | 31 (70.5) | |
| Female | 13 (29.5) | 13 (29.5) | |
| Age, y | 11.32 ± 2.9 | 11.34 ± 2.9 | 0.971 |
| Medication | 38 (86.4) | – | – |
| Number of drugs | 1.21 ± 0.68 | – | – |
| Type of medication | |||
| Stimulant | 38 (86.4) | – | – |
| Nonstimulant | 10 (22.7) | – | – |
| Breastfeeding | 33 (75.0) | 35 (81.4) | 0.605 |
| Type of respiration | |||
| Nasal | 17 (39.5) | 36 (81.8) | <0.001 |
| Buccal and/or mixed | 26 (60.5) | 8 (18.2) | <0.001 |
In the ADHD group, most patients were using 1 or more ADHD medications to manage symptoms. All patients under pharmacologic treatment were taking at least 1 stimulant drug. The 2 groups were not different regarding the history of breastfeeding. Prevalence of mouth breathing was significantly higher among children with ADHD compared with the control group ( P <0.001).
The different variables of dental occlusion evaluated in this study are shown in Table II . Children with ADHD had a significantly higher prevalence of dental rotation ( P = 0.021). The mean DAI score for patients with ADHD (28.99 ± 6.44) was significantly higher than that of the control group (26.38 ± 5.39) ( P = 0.042) ( Figs 1 and 2 ). Children with ADHD had a significantly higher prevalence of parafunctional oral habits ( P = 0.001), with significantly more bruxism ( P = 0.005), and a history of pacifier use ( P = 0.009) ( Fig 3 ).
