The prevalence of bruxism and oral parafunction activities among Israeli juveniles with autism spectrum disorder: A preliminary study during the COVID-19 pandemic

ABSTRACT

Objective

To evaluate the prevalence of oral habits, bruxism, and Temporomandibular Disorders (TMD) injuvenileswithautisticspectrumdisorder(ASD).

Methods

Data included 165 juveniles diagnosed with ASD, allocated to younger group aged 6 21 (n=86) and older group aged 13-21 (n=79).

Results

Sleep bruxism was reported by 26.7% in the younger group and by 5% in the older group. Awake bruxism was reported by 22% and 17.7%, respectively. Oral habits were reported by 43% of all participants, with similar rate in both groups. TMD related p ain was low in both groups (6.3% and 7% respectively). The influence of the COVID 19 pandemic on oral parafunction was moderate in the younger group (17.4%) and mild in the older group (8.6%), influence on bruxism was mild in both groups (5.8% and 2.5%, respectively).

Conclusion

The prevalence of bruxism and oral parafunctions was similar to the reported in the literature for the general population.

KEYWORDS:

• Autism spectrum disorder (ASD)
• awake/sleep bruxism
• Coronavirus 2019 (COVID 19)
• oral parafunction/habits
• temporomandibular disorders (TMD)

Introduction

Autistic spectrum disorder (ASD) is a neurological developmental disorder characterized by difficulties in social communication, repetitive behavior patterns, and atypical responses to sensory stimuli. Individuals with ASD often display typical behaviors, such as repetitive motor movements, repetitive use of sensory objects and stimuli, echolalia, and vocal tics [1]. The reported prevalence of ASD has increased over the past decade, and it is estimated as being 1:59 children (approximately 1.7%) in the United State [2]. The severity of ASD is divided into three levels (Table 1) according to the American Psychiatric Association Diagnostic and Statistical Manual of Mental Disorders 5th ed. (DSM-5) [1]

Table 1. Severity levels for autism spectrum disorder * [1].

Severity level	Social communication	Restricted, repetitive behaviors
Level 3- “Requiring very substantial support”	Severe deficits in verbal and nonverbal social communication skills cause severe impairments in functioning, very limited initiation of social interactions, and minimal response to social overtures from others	Inflexibility of behavior, extreme difficulty coping with change, or other restricted/repetitive behaviors markedly interfere with functioning in all spheres. Great distress/difficulty changing focus or action.
Level 2- “Requiring substantial support”	Marked deficits in verbal and nonverbal social communication skills; social impairments apparent even with supports in place; limited initiation of social interactions; and reduced or abnormal responses to social overtures from others.	Inflexibility of behavior, difficulty coping with change, or other restricted/repetitive behaviors appear frequently enough to be obvious to the casual observer and interfere with functioning in a variety of contexts. Distress and/or difficulty changing focus or action.
Level 1 “Requiring support”	Without supports in place, deficits in social communication cause noticeable impairments. Difficulty initiating social interactions, and clear examples of atypical or unsuccessful response to social overtures of others. May appear to have decreased interest in social interactions.	Inflexibility of behavior causes significant interference with functioning in one or more contexts. Difficulty switching between activities. Problems of organization and planning hamper independence.

*Adopted from DSM-5 [1].

Several reports in the literature have suggested that the prevalence of oral parafunctions and bruxism among individuals with ASD is higher than that of the general population [3–7]. The reported prevalence of bruxism in ASD children ranged from 21% to 60% [8]. However, Granja et al’s recent systematic review and meta-analysis concluded that the reports are too few and that the results are inconclusive [9]. In addition, bruxism was not evaluated according to the latest definition as being a muscular masticatory behavior that can occur during sleep (sleep bruxism [SB]) or during wakefulness (awake bruxism [AB]) [10].

SB activity may be characterized by either rhythmic (phasic) or non-rhythmic (tonic) movements, while AB is defined as a masticatory muscle activity during wakefulness that is characterized by repetitive or sustained tooth contact and/or by bracing or thrusting of the mandible. In otherwise healthy persons, bruxism should not be considered as a movement disorder or a sleep disorder, but rather as a behavior that can be a risk and/or even a protective factor for certain clinical conditions (e.g., restoring the patency of the upper airway whilst asleep, reducing the risk of detrimental chemical tooth wear by increasing salivation in case of gastro-esophageal disorders) [10]. Indeed, bruxism is no longer considered as either an oral parafunction or an oral habit since the performance of those movements is under the individual’s fully conscious control [11]. Unlike oral parafunctions, bruxism is a centrally mediated behavior influenced by psychological factors, in particular, stress sensitivity, individual character traits, and anxiety, and is not performed voluntarily or consciously [12].

The etiology of bruxism is multifactorial and not fully understood. There are several reports of increased bruxism activity in individuals with neurological disorders [13], however it is unclear whether the bruxism is related directly to the neurological disorder or to other contributing factors, such as medication intake or sleep disorders.

Individuals with ASD often require the use of medications, the most common of which are sleep medicines, stimulants (e.g., methylphenidate), anti-psychotics, and anti-depressants [14], and they may be associated with increased bruxism activity [15]. In addition, a sleep disorder is a common symptom associated with ASD, with approximately 50% to 80% of juveniles diagnosed with ASD suffering from sleep problems [16], poor sleep quality is a known risk factor for sleep bruxism [17].

Temporomandibular disorders (TMDs) comprise number of clinical problems involving the masticatory muscles, the temporomandibular joints, and related structures [18]. These prevalent musculoskeletal disorders cause pain and disability in about 5%–12% of the population. A recent systematic review and meta-analysis found that the oral health-related quality of life was significantly impacted by TMDs, may be due to physical (pain) and psychosocial symptoms of the underlying illness [19]. The etiology of the TMD is multifactorial. The cause-and-effect relationship between TMD symptoms, bruxism, and parafunctional activity is still controversial [12,20].

Early diagnosis of TMD is important in order to avoid complications and chronic pain. Diagnosis of TMD in juveniles with ASD is challenging due to their communication difficulties and their frequent display of atypical pain reactions [21]. The prevalence of TMD among juveniles with ASD has rarely been reported [22].

This study was conducted during the COVID-19 pandemic. Recent reports have described the influence of stress, anxiety, and depression related to the pandemic on bruxism activity (both SB and AB), oral parafunction performance, and TMD [23,24]. A systematic review by Minervini et al. showed that the state of uncertainty in which people lived during this pandemic, especially through stress, created muscle hyperactivity, and aggravation of bruxism, which are all causal factors and symptoms of TMD [25]. To the best of our knowledge, the influence of these stressors on those parameters in juveniles with ASD, however, has never been evaluated.

Therefore, the aim of this study, was to evaluate the prevalence of oral habits, bruxism, (sleep and awake) and TMD symptoms in juveniles with ASD. The study’s null hypothesis was that bruxism, oral habits, and TMD symptoms are more prevalent in juveniles with ASD compared to the general population. Those higher rates may be related either to the primary neurological diagnosis of ASD or they may be secondary to medication intake. We also tested the hypothesis that stress related to the COVID-19 pandemic had an influence on the oral behavior of juveniles with ASD.

Methods

Study population

The study population included subjects aged 6–21 years (mean age ± standard deviation 12.55 ± 4 years, 131 males and 34 females) who had been diagnosed with ASD severity levels 2 and 3 according to the DSM-5 [1]. They were all students studying at a special education primary/high school for autism. Juveniles with severity level 1 were not part of the present study population. Data were collected from questionnaires sent to each participant’s parents/caregivers from February to June 2021. A total of 165 questionnaires were filled in. The participants were divided into a younger group aged 6–12 years (n = 86, mean age 9.28 ± 1.58 years) and an older group aged 13–21 years (n = 79, mean age 16.1 ± 2.43) (Table 2).

Table 2. Participants according to age group.

Group	n	Age Range (years)	Mean (±SD)	Median	M/F
Younger	86	12–6	9.28 (1.58)	9	1/4.73
Older	79	21–13	16.1 (2.43)	16	1/3.16
Total	165	21–6	12.55 (4)	12	1/3.85

SD, standard deviation; M/F, male/female.

Anonymity, consent, and procedure

After telephonic coordination with the school principal, the parents/caregivers of the students received a full explanation of the importance and purpose of the study from the authors. Since the study was performed during the COVID-19 pandemic, it was not possible to meet with the parents/caregivers directly, and explanations were therefore provided digitally. After receiving their consent to include their child in this analysis, a link to their cellphone or computer was sent for downloading the questionnaires. A printed questionnaire was supplied by request. The questionnaire was completely anonymous. The results of the questionnaires were automatically uploaded into one large database, and the anonymity of each participant was ensured. The study was approved by the Chief Investigator of the Israeli Ministry of Education prior to data collection (permission No. 11361b, August 23 2020).

The questionnaires

The questionnaires included information on demographics (age and sex), medical health, and medications consumed by the subjects. Medications known to be associated with bruxism, such as selective serotonin reuptake inhibitors (SSRI), serotonin noradrenaline reuptake inhibitors (SNRI), methylphenidate (Ritalin), and antipsychotic medications (risperidone and quetiapine) were queried, as was the use of medical cannabis.

The included items on sleep and awake bruxism, oral habits, and questions about painful and non-painful TMD symptoms were based upon validated questionnaires used in a previous survey of the general juvenile population in Israel [26].

Finally, the parents/caregivers were questioned about the influence of the COVID-19 pandemic on the participants’ general behavior, Bruxism, and oral habits.

Parafunctional activity

The parents/caregivers were queried about their children’s oral habits. The following questions about habits were asked on the performance of the following oral habits: biting down on hard objects (pens, pencils, etc.), cheek/lip biting, onychophagy (nail biting), gum chewing, pica (chewing non-food materials), food pouching, and thumb sucking]. The answers were: no, occasionally, often, on a daily basis. Only habits that were performed often or on a daily basis were taken as being positive for the purpose of data analysis.

Sleep and awake bruxism (SB, AB)

The diagnosis of SB and AB depended upon the parents/caregivers’ awareness and recorded as being “unknown” if they were unsure. The following questions about bruxism were asked: 1. do you hear your child grinding his/her teeth during sleep, or are you aware that the child clenches the teeth during sleep? 2. Have you noticed whether your child grinds/clenches his/her teeth or jaws (tight the muscles of the face, without contact of the teeth) during waking hours? The three possible answers to these questions were: yes/no/I don’t know, and they answers were dichotomized into “yes” and “no/don’t know” for data analyses. It was recently recommended that the diagnosis of bruxism should be graded “possible” when based solely upon reports, “probable” when based upon clinical examination, or “definite” when based upon a positive instrumental assessment [10]. Accordingly, the diagnosis of SB and AB in the current study should be graded as “possible”.

Temporomandibular symptoms

Parents/caregivers were queried about TMD complaints and symptoms. The following questions were asked: 1. Does your child complain of pain in his/her temple, face, jaws, or pre-auricular area (in front of the ear) Yes/No.2. Does your child complain of pain in the neck area? Yes/No. If the parents/caregivers replied affirmatively to those questions, they were asked to grade the pain intensity as following: mild pain, moderate pain and severe pain. 3. Does your child have difficulties in opening his/her mouth? Yes/No 4. Does your child have difficulties in chewing? Yes/No. 5. Do you hear joint noises (clicking or popping) during your child’s jaw movements or chewing? Yes/No.

Dental wear

Finally, the parents/caregivers were asked if their child had been examined by a dentist during the last year, and if the dentist mentioned that he/she had signs of dental wear.

Statistical analysis

Descriptive statistics followed by a univariate Chi-square test or Fishers’ Exact Test and T-test analyses were used. All tests were two-tailed. The results of the statistical tests that showed a probability of p < .05 were considered significant. The data were analyzed using the IBM SPSS statistics version 23.0. (SPSS, Inc., Chicago, IL USA).

Results

The parents/caregivers’ reported medical conditions of the study participants were: 124 (75%) ASD alone, 15 (9%) ASD and epilepsy, and 26 (15.75%) ASD and other medical conditions (congenital cardiac malformation, gastro-intestinal disorders, hypothyroidism, and vision problems).

Daily medication use was reported for 97 of the participants (58.8%), with 83 (50.3%) of them using at least one medication associated with bruxism (risperidone was the most common medication used as a single treatment (31, 18.8%), and 32 (19.4%) using more than one medication. Medical cannabis was used by 25 participants (15.2%), but only three participants took it as a sole treatment. In addition, 16 (19.4%) participants reported previous use of medical cannabis, while 68 participants (41.2%) did not regularly consume any medication.

Initially, participants who reportedly took medications that could influence the occurrence of bruxism (SB and/or AB) (Table 3) had been analyzed as a separate group. Having not found any significant differences in all the parameters evaluated among participants who did and did not consume those medications, the groups were combined and analyzed as one.

Table 3. Medication consumption according to age group.

Group	n	No Medication	Medication Associated with Bruxism	Other Medication	Medical Cannabis*
Younger	86	37 (43%)	40(46.5%)	9(10.5%)	10(2)
Older	79	30 (38%)	43(54.4%)	6(7.6%)	15(1)
Total	165	68(41.2%)	83(50.3%)	14(8.5%)	25(3)

Younger, 6–12 years; Older, 13–21 years *Cannabis with other medication (cannabis as sole treatment)

AB was reported by 20% of the parents/caregivers, with similar rates in both age groups (22% for the younger group and 17.7% for the older group). SB was more prevalent in the younger group (26.7%) compared to the older group (5%). More parents/caregivers of the older age group reported not knowing about the presence of SB (26.6% vs. 10.5% for the younger group). General sleep disorders were reported by most of the parents/caregivers (61%), and 24% of them reported frequent or nightly occurrence. The prevalence of SB and AB are summarized in Table 4.

Table 4. Prevalence of sleep and awake bruxism.

Group	n	SB	Unknown SB	AB	Unknown AB	AB & SB
Younger	86	23(26.7%)	9(10.5%)	19(22%)	8(9.3%)	13(15.1%)
Older	79	4(5%)	21(26.6%)	14(17.7%)	10(12.6%)	3(3.8%)
Total	165	27(16.3%)	30(18.2%)	33(20%)	1810.9%)	16(9.7%)

SB, sleep bruxism; AB, awake bruxism; Younger, 6–12 years; Older, 13–21 years.

Most of the juveniles (n = 95, 57.6%) had been examined by a dentist in the past year. The parents/caregivers of 24 of them (25.3%) reported that the dentist mentioned that their child had dental wear (n = 10, 21.3% in the younger group, and n = 14, 29.2% in the older group). Those values significantly correlated with the parents/caregivers’ report on SB and AB only in the younger age group (p = .008 for SB and p = .01 for AB).

The presence of oral habits was reported by 43% of the parents/caregivers, with similar rates in both age groups. The most common daily habit they reported was object biting (12.1%) followed by nail biting (9.7%). Tongue thrusting was reported by 11 parents/caregivers (6.6%), mouth breathing was reported by (25%) of the parents/caregivers, and tics of any kind by 56% of the parents/caregivers. The prevalence of oral habits is summarized in Tables 5 and 6. The correlation between oral habits and bruxism was highly significant for both SB and AB (p = .004 and p = .015 respectively).

Table 5. Prevalence of oral habits according to age group.

Group	n	No Oral Habits	At Least One Oral Habit	More Than One Oral habit
Younger	86	48(55.8%)	38(44.2%)	17(19.8%)
Older	79	46(58.2%)	33(41.8%)	14(17.7%)
Total	165	94(57%)	71(43%)	31(18.8%)

Younger, 6–12 years; Older, 13–21 years. The oral habits are listed in the Methods section.

Only habits that were performed often or daily were taken as being positive.

Table 6. Prevalence of the various oral habits (n = 165).

Oral Habit	Never	Occasional	Often	Daily
Chewing gum	120(72.7%)	38 (23%)	5 (3%)	2 (1.2%)
Nail biting	118(71.5%)	18(10.9%)	13(7.9%)	16(9.7%)
Object biting	97(58.8%)	32(19.4%)	16(9.7%)	20(12.1%)
Cheek/lip biting	141(85.5%)	20(12.1%)	3(1.8%)	1(0.6%)
Food pouching	137(83%)	16(9.7%)	6(3.6%)	6(3.6%)
Thumb sucking	150(90.1%)	7(4.2%)	1(0.6%)	7(4.2%)
Pica	124(75.1%)	28(17%)	10(6%)	3(1.8%)

The prevalence of pain related to TMD as reported by the parents/caregivers was low in both age groups. Only 11 participants reportedly had medium or severe pain in both age groups: 6 (7%) in the younger group and 5 (6.3%) in the older group. Symptoms possibly related to TMD are listed in Table 7.

Table 7. Symptoms related to TMD* according to age group.

Group	Pain in the facial Area	Difficulties in Mouth Opening	Difficulties in Chewing	Reported Jaw Noises
Younger	6(7%)	9(10.6%)	8(9.4%)	11(12.8%)
Older	5(6.3%)	12(15.2%)	11(13.9%)	5(6.3%)
Total	11(6.7%)	21(12.7%)	19(11.5%)	16(9.7%)

*TMD, temporomandibular disorder; Younger, 6–12 years; Older, 13–21 years.

This study was conducted during the COVID-19 pandemic. The parents/caregivers were asked about the influence of the pandemic on their child’s behavior and on his/her oral habits. Most of the parents/caregivers (73.3%) reported that the pandemic did have some influence on their children (27.9% reported that it was strong or very strong). In response to items on bruxism and oral habits, 12.7% of the parents/caregivers reported that the pandemic did have an influence on their child’s oral habits (17.4% in the younger group and 8.6% in the older group), with 4.2% affecting bruxism, SB, or AB (5.8% in the younger group and 2.5% in the older group). The influence of COVID-19 on the children’s general behavior is summarized in Table 8.

Table 8. Parent/Caregivers reported influence of COVID-19 on the study subjects.

	Extent of Influence	Younger Group (n = 86)	Older Group (n = 79)	Total (n = 165)
Anxiety level	None	30	30	60(34.6%)
	Mild	18	27	45(27.3%)
	Moderate	21	10	31(18.8%)
	Strong	17	12	29(17.6%)
Obsessive behavior	None	32	32	64(38.8%)
	Mild	23	22	45(27.3%)
	Moderate	11	12	23(13.9%)
	Strong	20	13	33(20%)
General behavior	None	18	16	34(20.6%)
	Mild	20	21	41(24.8%)
	Moderate	21	23	44(25.6%)
	Strong/very strong	27	19	46(27.9%)

Younger, 6–12 years; Older, 13–21 years.

Discussion

Numerous reports in the literature have suggested that the prevalence of oral parafunctions and bruxism among individuals with ASD is higher than in the general population [3–8]. However, none of those studies included any data on the type of bruxism (SB or AB) or on the medication use of the subjects. In addition, although bruxism and oral habits can be a precursor to TMD disorders, TMD symptoms were not recorded in those articles, and their association with bruxism and oral habits in ASD juvenile has rarely been reported in the literature [22].

In Israel, children who are diagnosed as having autism with severity levels 2–3 attend special schools for autism, from age 6 to 21 years [1], while children with severity level 1 are integrated into regular schools. Data for the current study were collected from questionnaires distributed to parents/caregivers of students studying solely at special schools for autism, thereby excluding juveniles with severity level 1.

The questionnaire used in this study had been validated in a previous survey of the general population in Israel [26]. The present analysis was based upon parental and not self-reporting due to cognitive and communication difficulties of the participants. A recent study aimed at evaluating and validating a questionnaire on TMD symptoms was given to caregivers of children with ASD in order to aid the anamnesis and diagnosis of those children. The study finding showed high agreement between the caregivers and verbal children with ASD report, suggesting that reporting by parents/caregivers is a reliable method that can be useful in the diagnosis of TMDs symptoms among children with ASD [22].

The data in the present study analysis were divided into two groups according to the participants’ age: younger group (6–12 years) and older group (13–21 years). SB was reportedly present in 26.7% of the younger group, a figure that was almost double than that reported in the general population of the same age in Israel (13.5%) [27]. This difference may be due to the high level of reported sleep disorders (61%), in accordance with Richdale et al [16]. Further studies are warranted to validate those possibilities. Only 5% of the parents/caregivers in our older group reported SB, while two studies conducted in the general adolescent population in Israel [26,28] found a higher prevalence (9.2% and 14.8%). The difference may be due to the high number of parents/caregivers in the older age group who reported not knowing about the presence of SB (26.6%), reducing the reliability of the report in the older group with regarding to SB.

AB was reported by 22% of the parents/caregivers in the younger age group and by 17.7% of them in the older age group. An Israeli study that examined children aged 5–12 years found signs of AB on soft tissues (linea alba and tongue indentation) in 19.9% of them [27], comparable to the reported rate in the present study. The prevalence of AB in the older group closely resembled one study in the general Israeli population (19.2%) [28] and was lower than that reported in another (34.5%) [26]

Oral habits were reported by 43% of the current study cohort, with similar rates for the younger and older age groups. In addition, 18.8% of them reported more than one oral habit, again with similar rates in both age groups. These results are in accordance with the report on the general adolescent population in Israel and lower than those reported in children population [26,27]. The most common daily habit reported in both age groups in the current study was object biting (12.1%).

The present study questionnaires also included items on TMD symptoms. Parent/caregivers-reported pain related to TMD was low and similar in both age groups (6.7%). The prevalence of mouth opening difficulties (12.7%) and chewing difficulties (11.5%) were higher and similar in both age groups. These data, however, are insufficient to determine the prevalence of painful TMDs because of the complexity of pain assessment in individuals with ASD. Until recently, pain perception among individuals with ASD was assumed to be impaired since they often react differently to pain stimulation or even seem to be indifferent to pain [20]. It was recently suggested that their pain perception is normal but can be misdiagnosed by caregivers [21].

One-half of the present study participants reportedly had daily consumption of at least one medication possibly associated to bruxism [15]. Surprisingly, there were no significant differences between those taking medications and those who did not in all the evaluated parameters. This may be explained by the grade of diagnosis of bruxism in the present study (possible), or by the neurological developmental disorder that characterized the study population. Additional studies are warranted to clarify a possible link between SB and medication intake in the juvenile ASD population.

The use of cannabis as treatment for ASD symptoms is relatively new and not well studied. Medical cannabis was used by 25 (15.2%) of the current study participants, however, only 3 participants used it as a single treatment, therefore the influence of cannabis on bruxism in ASD juveniles could not be evaluated.

This study was conducted during the COVID-19 pandemic which influenced the routine life of the world population, inducing stress, anxiety, and depression. Conducting the study during this era precluded direct contact with the parents/caregivers. In addition, no dental or medical examinations could be performed because of social distancing prohibitions. On the other hand, the COVID-19 pandemic was also an opportunity to examine the influence of the pandemic on the participants’ oral habits and especially on bruxism. Bruxism tends to be influenced by stress and anxiety levels [29], especially AB [30]. It was also suggested that it can be a protective mechanism to reduce stress [31]. An earlier study conducted in Israel during the pandemic showed a significant increase in the report of bruxism and oral habits [23]. In the present study, the parents/caregivers were also queried about the influence of the pandemic on their children’s behavior and oral habits. Most of them (73.3%) reported that the pandemic did influence their children, and almost two-thirds reported an increase in the anxiety level and an elevation in obsessive behavior (~20% to a considerable or very considerable extent). The influence of the pandemic on oral habits was moderate in the younger group (17.4%) and mild in the older group and (8.6%), while the influence on bruxism was mild in both groups (5.8% in the younger group and 2.5% in the older group).

Study limitations

This was a preliminary study meant to raise the level of awareness of this important topic. Accordingly, it was not without limitations. The major limitations of the study are the following:

• As in other cross-sectional studies, the present study is unable to make a causal inference and is susceptible to a sampling bias. Applying a longitudinal, long-term design, would enable a more profound detection of trends and relationships within the data collected.

• The present study was conducted during the COVID-19 pandemic, precluding the performance of physical examinations on the ASD study cohort for determining definitive diagnoses, because of social distancing prohibitions. Since this is a questionnaire-based study, we could analyze only symptoms and not actual muscular or articular disorders. A single symptom from the masticatory system is not synonymous with a TMD, nor does it automatically lead to the diagnosis of a TMD. Consistent implementation of validated criteria in future studies will enable a more reliable definition of TMD cases.

• Despite the fact that a previous study found that the reporting by parents/caregivers is a reliable method that can be useful in diagnosis of TMD symptoms among children with ASD [22], the study population (defined as level 2 and 3 according to the to the DSM-5) [1] is difficult to compare with a normal population of children who are capable of answering the questionnaires by themselves.

Conclusions

In conclusion, this preliminary study aimed to test the null hypothesis that there will be differences in the extend of bruxism, oral habits, and TMD between the sample under examination (juveniles with ASD) and the general population. The assumption that the differences may be related either to the primary neurological diagnosis of ASD or they may be secondary to medication intake was rejected. In addition, the use of medication associated with bruxism had no apparent influence on SB. We also tested the hypothesis that stress related to the COVID-19 pandemic had an influence on the oral behavior of juveniles with ASD. An increased anxiety level and an elevation in the obsessive behavior were reported by the parents/caregivers, however, they described the influence on bruxism and oral habits as relatively mild/moderate. Additional studies are warranted to evaluate the prevalence and risk factors associated with bruxism, oral parafunction, and TMD in young ASD populations.

Author contributions

Orit Winocur-Arias: contributed to the design of the study, analysis, acquisition, and interpretation of data and drafted the manuscript; Amitai Bat Chen: contributed to the design of the study, analysis, acquisition, and interpretation of data; Efraim Winocur: contributed to interpretation of data; drafted the manuscript and critically revised the manuscript; Tom Shmuly: critically revised the manuscript; Osnat Grinstein Koren: critically revised the manuscript; Shoshana Reiter: contributed to the design of the study, analysis, and interpretation of data and drafted the manuscript. All authors gave their final approval and agreed to be accountable for all aspects of the work.

Institutional review board statement

The study was approved by the Chief Investigator of the Israeli Ministry of Education prior to data collection (permission No. 11361b, August 23 2020).

Informed consent statement

The Chief Investigator of the Israeli Ministry of Education approved the study after verifying its anonymity (permission No. 11361b, August 23 2020). All parents/caregivers of the participants consent to use their data in research purposes

Abbreviations

ASD	=	Autistic spectrum disorder
TMD	=	Temporomandibular disorders
COVID 19	=	Coronavirus 2019
DSM-5	=	Diagnostic and Statistical Manual of Mental Disorders 5th ed.
SB	=	Sleep bruxism
AB	=	Awake bruxism
SSRI	=	Selective serotonin reuptake inhibitors
SNRI	=	Serotonin noradrenaline reuptake inhibitors

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.