Sleepiness in children with severe malocclusion compared with in children with neutral occlusion

Introduction

The study aimed to compare daytime sleepiness in children with severe malocclusion with healthy children with neutral occlusion (controls) and to analyze associations between daytime sleepiness and craniofacial morphology in children with severe malocclusion.

Methods

In 120 children with severe malocclusion (73 girls, 47 boys; mean age, 11.96 years; mean body mass index [BMI] score, 18.97 kg/m ² ) and 35 controls (18 girls, 17 boys; mean age, 11.97 years; mean BMI score, 20.28 kg/m ² ), sleep and daytime sleepiness were recorded using Epworth Sleepiness Scale and Berlin Questionnaire. Occlusion was registered clinically, and craniofacial morphology was assessed on lateral cephalograms. Differences in daytime sleepiness and sleep between the groups and associations between daytime sleepiness and sleep and craniofacial morphology were analyzed by a general linear model adjusted for age, gender, and BMI score.

Results

Daytime sleepiness occurred significantly more often in children with malocclusion than in control subjects ( P = 0.015). There was a tendency for children with malocclusion to feel extremely tired during the day more often than controls ( P = 0.054). There was no significant difference between the groups in sleeping hours during night-time, but the amount of sleep was negatively associated with age ( P <0.001) and BMI score ( P = 0.004). Only maxillary inclination was significantly associated with daytime sleepiness ( P = 0.043).

Conclusions

Daytime sleepiness occurred significantly more often in children with severe malocclusion than in those with neutral occlusion, and the association between daytime sleepiness and craniofacial morphology may exist. The results might prove valuable in interdisciplinary collaboration between medical doctors and orthodontists in diagnostics, prevention, and treatment of children at risk for sleep-disordered breathing.

Highlights

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Daytime sleepiness occurred more often in children with malocclusion compared with in controls.
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For single malocclusion traits, children with deep bite and open bite were sleepier than controls.
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No difference in hours of sleep between groups, but sleep was associated with age and body mass index.
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Daytime sleepiness and craniofacial morphology may be related in children with malocclusion.

Sleep is an essential component of children’s general well-being as well as of their development, learning process, and growth. ^, The need for sleep varies by age, and the optimal amount of sleep for children aged 5-16 years is 10 h/night. Compromised sleep, especially interference with deep sleep, can be severely damaging in terms of health. ^, Several types of sleep disorders can impair sleep quality and increase the risk of comorbidities such as diabetes and heart diseases, which, in the worst scenario, can lead to premature death. ^,

Sleep-disordered breathing (SDB) occurs in 4%-11% of children, but the prevalence might be higher as a large number remain undiagnosed during childhood. ^, Obstructive sleep apnea is an SDB that affects 1%-5% of children and is characterized by repetitive complete or partial collapse of the upper airways during sleep. Anatomic morphology and the dimensions of the upper airways can hence affect the quality of sleep as constricted airways can predispose to decreased sleep quality. ^, ^, The most common cause of constricted airways in children is enlarged adenoids and tonsils. Other well-known predisposing factors for SDB are obesity, disturbances of the upper airway neuromotor response, and dentofacial morphology. ^, Symptoms of decreased sleep quality in children can be snoring, nocturia, learning difficulties, irritability, behavioral disorders such as attention deficit hyperactivity disorder, and, in some patients, daytime sleepiness. ^,

Previous studies have shown that SDB in children may be related to dentocraniofacial changes, which can lead to an anatomic constriction of the upper airways. ^, Such changes include nasal septal deviation and narrow nostrils, increased anterior face height, decreased length of the maxilla and the mandible, increased length of the soft palate/elongated uvula, and large horizontal maxillary overjet because of mandibular retrognathia and crossbite in combination with a narrow and high palate. ^, ^, There is also an increased occurrence of SDB among children with syndromes related to hypoplastic development of the midface (Crouzon’s, Down’s, Pierre Robin, and Treacher-Collins syndrome), enlarged tongue (Beckwith-Wiedemann Syndrome), and neuromuscular diseases (cerebral paresis and myotonic dystrophy). ^, In addition, tooth agenesis and SDB seem to be related, which confirms the importance of dental eruption in the development of dental arches and jaws.

Accordingly, it may be assumed that children who need orthodontic treatment because of severe malocclusion may have an increased risk of developing symptoms and signs related to SDB. If so, interdisciplinary collaboration between medical doctors and specialists in orthodontics may prove valuable in the diagnostics, prevention, and treatment of children with symptoms and signs of SDB who need orthodontic treatment. Thus, this study examined daytime sleepiness and sleep in children with severe malocclusion before orthodontic treatment compared with in children with neutral occlusion and analyzed associations between daytime sleepiness and sleep and craniofacial morphology in children with severe malocclusion. The null hypotheses were that there was no difference in daytime sleepiness and sleep between children with severe malocclusion and children with neutral occlusion and that daytime sleepiness and sleep were not associated with craniofacial morphology in children with severe malocclusion.

Material and methods

This study consisted of a group of children with severe malocclusion and a group of children with neutral occlusion.

All children with severe malocclusion who were referred for orthodontic treatment at the Postgraduate Clinic of Orthodontics, University of Copenhagen, in accordance with the procedure for screening the child population for severe malocclusion entailing health risks between October 2019 and December 2020 were invited to participate in the study. The health risks related to malocclusion were as follows: risk of damage to teeth and surrounding tissue; risk of functional disorders; risk of psychosocial stress; and risk of late sequela as forward migration of maxillary incisors, late development of extreme deepbite, and asymmetrical facial development. The list of malocclusions that should be treated because of health risks is listed in a publication by Solow. The inclusion criteria were as follows: children aged 9-14 years, indication for orthodontic treatment in accordance with the procedure for screening the child population for severe malocclusion entailing health risks, and no previous orthodontic treatment. The exclusion criteria were as follows: known general and/or craniofacial syndromes or disorders and known sleep or respiratory disorders. The group of children with severe malocclusion then consisted of 120 children (73 girls and 47 boys), with a mean age of 11.96 years and an average body mass index (BMI) score of 18.97 kg/m ² ( Fig 1 ; Table I ).

Table I

Age, BMI score, ESS score, and number of sleeping hours in children with malocclusion and children with neutral occlusion

Variable	Children with malocclusion		Children with neutral occlusion		P value
Variable	Mean ± SD	Median	Mean ± SD	Median	P value
Age (y)	11.96 ± 1.34	12.08	11.99 ± 1.12	12.08	0.973
BMI score (kg/m)	18.97 ± 3.40	18.20	20.28 ± 3.88	19.05	0.062
ESS score	4.03 ± 3.49	3.00	2.60 ± 2.50	2.00	0.015 ^∗
Sleep (h)	9.05 ± 0.90	9.00	8.98 ± 0.93	9.00	0.949

Note. For ESS, 0 is the lowest score for daytime sleepiness (no daytime sleepiness), whereas 24 is the highest score.

SD , standard deviation.

∗ P <0.05.

The children with neutral occlusion were enrolled for another study conducted at the Section of Orthodontics, Department of Odontology, University of Copenhagen, in which similar variables were registered using methods similar to this study. The study was approved by the Committee of Research Health Ethics of the Capital Region (protocol no. H-17011521) and the Danish Data Protection Agency (protocol no. SUND-20017-29). The children were recruited from the the municipal dental services in and around Copenhagen. The inclusion criteria were as follows: children aged 9-14 years, neutral dental occlusion according to Björk, no indication of orthodontic treatment in accordance to the procedure for screening the child population for severe malocclusion entailing health risks, and no previous orthodontic treatment. The exclusion criteria were known general and/or craniofacial syndromes or disorders and known sleep or respiratory disorders. The group of children with neutral occlusion consisted of 35 children (18 girls, 17 boys) with a mean age of 11.97 years and a BMI score of 20.28 kg/m ² .

The power calculation was performed before undertaking the study on the basis of the score of the Epworth Sleepiness Scale (ESS) score on a logarithmic scale. Previously, a standard deviation of 3.3 was recorded for the ESS score, corresponding to a standard deviation of 0.32 on the logarithmic scale. To establish a difference in the mean of at least 60%, approximately 35 children with neutral occlusion and 118 children with malocclusion were required to have sufficient power (90%) to identify statistically significant differences at the 5% level of significance.

Sleep and daytime sleepiness were recorded by 2 standard and validated questionnaires, the ESS and the Berlin Questionnaire (BQ), ^, both modified for children. In cooperation with the parents, the children filled out the questionnaires. ESS scores the degree of daytime sleepiness and consists of 8 questions about how likely it was for the child to doze off in various situations in their everyday life. The reply for each situation was scored in the interval between 0 and 3, in which 0 indicated that the child would never doze off, and 3 indicated that such a situation would almost always cause the child to doze off. A final score was calculated for each questionnaire, with 0 as the lowest score for daytime sleepiness (no daytime sleepiness) and 24 as the highest score for daytime sleepiness ( Table I ). BQ consisted of 9 questions concerning snoring and quality of sleep ( Table II ). ^,

Table II

Results of the BQ in the 2 groups

Variable	Children with malocclusion						Children with neutral occlusion						P value
Variable	n	Never	1-2 times/mo	1-2 times/wk	3-4 times/wk	Almost every night	n	Never	1-2 times/mo	1-2 times/wk	3-4 times/wk	Almost every night	P value
How often do you snore?	111	73.0	7.2	7.2	5.4	7.2	33	90.9	3.0	3.0	0	3.0	1.00
Has anyone noticed that you have stopped breathing during sleep?	113	95.6	1.8	2.7	0	0	33	100	0	0	0	0	1.00
Have you experienced awakenings with gasping for breath or feeling that you are suffocating?	112	99.1	0.9	0	0	0	33	100	0	0	0	0	1.00
How often do you feel inadequately rested?	119	19.3	37.8	29.4	13.4	0	35	28.6	31.4	34.4	5.7	0	0.424
How often do you feel abnormally or extremely tired during the day?	119	40.3	41.2	13.4	4.2	0.8	35	68.6	22.9	8.6	0	0	0.054
Are you restless in your sleep, resulting in curled-up bed sheets?	120	56.4	16.7	14.2	5.0	8.3	34	61.8	11.8	5.9	8.8	11.8	0.294

Note. Values are presented as a percentage. The remaining 3 questions of BQ, which are not displayed in Table II , include: “Do you snore?,” “How loud do you snore?” and “How many hours do you sleep at night?” The results from the question “Do you snore?” in children with malocclusion were as follows: 24.4% did snore, 68.1% did not snore, and 7.6% did not know. In children with neutral occlusion, the results were as follows: 8.6% did snore, 85.7% did not snore, and 5.7% did not know. The difference was not significant ( P = 0.101).

The results from the question “How loud do you snore?” in children with malocclusion were as follows: 72.3% no sound, 21.4% louder than breathing, 5.4% as loud as speaking, and 0.9% louder than speaking. In children with neutral occlusion, the results were as follows: 91.0% no sound, 6.1% louder than breathing, 3.0% as loud as speaking, and 0.0% louder than speaking. The difference was not significant ( P = 0.566). The results from the question “How many hours do you sleep at night?” are shown in Table I .

The occlusion was registered clinically and registered according to their type in 3 planes ^, ^, : sagittal plane (neutral [Class I], distal [Class II], or mesial [Class III] occlusion) transversal plane (neutral, crossbite, or scissors bite on ≥1 tooth), and vertical plane (neutral, open bite [<0 mm], or deepbite [>5.5 mm]). Among the children with asymmetrical occlusion, the most severe deviation was registered ( Table III ).

Table III

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