Oral health among preschool children with autism spectrum disorders: A case-control study

Abstract

Aim:

To assess and compare the oral health status of preschool children with and without autism spectrum disorders.

Methods:

A random sample of 347 preschool children with autism spectrum disorder was recruited from 19 Special Child Care Centres in Hong Kong. An age- and gender-matched sample was recruited from mainstream preschools as the control group. Dental caries status, gingival health status, tooth wear, malocclusion, dental trauma and oral mucosal health were assessed and compared between the two groups.

Results:

It was feasible to conduct a comprehensive oral health screening among 74.1% (257) of the children with autism spectrum disorder. The mean age was 59 ± 10 months (range from 32 to 77 months), of whom 84.4% were males. Children with autism spectrum disorder had better gingival health than children without autism spectrum disorder (mean plaque score and gingival score p < 0.001). Children with autism spectrum disorder had less caries experiences than children without autism spectrum disorder (mean decayed, missing and filled surfaces and decayed surfaces, p < 0.05). Children with and without autism spectrum disorder had similar prevalence of tooth wear, malocclusion, dental trauma experience and oral mucosal lesions (p > 0.05).

Conclusion:

Differences in oral health status exist among preschool children with and without autism spectrum disorder. Preschool children with autism spectrum disorder exhibited lower caries experiences and better gingival health than children without autism spectrum disorder.

Keywords

autism spectrum disorders case-control studies oral health status preschool children

Introduction

Autism spectrum disorder (ASD) is a spectrum of developmental disorders, which includes autistic disorder (AD), Asperger’s syndrome (AS) and pervasive developmental disorder not otherwise specified (PDD-NOS). It is characterized by impairments in social interaction and communication, along with repetitive, stereotyped patterns of behaviour, interests or activities (American Psychiatric Association (APA), 2000). The prevalence of ASD is 20 per 10,000 live births (Williams et al., 2006) with a gender ratio of 4:1 between males and females, respectively (Holguin, 2003).

ASD is associated with numerous medical issues in childhood (Johnson et al., 2007; Levy et al., 2009). Apart from communication difficulties, children with ASD experienced higher rates of poor mental health (e.g. cognitive disability, epilepsy) and behavioural problems (Bradley et al., 2004; Brereton et al., 2006). In particular, there is evidence that anxiety and depression (Weisbrot et al., 2005) as well as attention deficit and hyperactive disorders (ADHD) are more common. Parents also reported higher rates of tactile sensitivity and food selectivity in children with ASD (Valicenti-McDermott et al., 2006). Sleep disturbances may be more common in children with AS and high-functioning autism compared to healthy controls (Allik et al., 2006).

These medical issues can also attribute to particular oral diseases/conditions among children with ASD. It has been suggested that oral care for children with ASD is compromised due to their difficulties in their communication skills and reduced cognitive functioning, which may lead to poor oral hygiene, gingivitis and/or periodontal problems (Jaber, 2011; Luppanapornlarp et al., 2010). Furthermore, poor periodontal health has been attributed to the tactile defensiveness arising from tooth brushing and use of other intra-oral oral hygiene devices and consequently a lack of compliance with routine (and necessary) oral hygiene practices (Shapira et al., 1989).

Children with ASD may have sensory hypersensitivities to visual, auditory, olfactory or gustatory stimuli that were associated with oral care difficulties at home and behavioural problems in the dental office (Stein et al., 2011). Food selectivity and atypical dietary behaviour patterns may also have implications for dental caries (Smith et al., 2005). It has been reported that children with ASD have a greater caries experience (Jaber, 2011), although other studies refute this statement (Loo et al., 2008; Lowe and Lindemann, 1985; Namal et al., 2007). Children with neurological disorders are prone to self-injury and dental trauma is common, and even self-extract of teeth (Baghdadli et al., 2003; Matson and Lovullo, 2008; Poustka and Lisch, 1993). Moreover, a high prevalence of bruxism (excessive grinding/clenching of teeth) has been observed in children and adults with ASD (Barnoy et al., 2009; Fahlvik-Planefeldt and Herrstrom, 2001; Muthu and Prathibha, 2008; Orellana et al., 2012). Others, however, have not found significantly higher levels of dental trauma, self-injury or bruxism among children with ASD than in children without ASD (Altun et al., 2010b; Fahlvik-Planefeldt and Herrstrom, 2001; Orellana et al., 2012).

Thus, evidence of an increased risk of oral health problems among children with ASD is contradictory and inconclusive. This, in part, relates to the issue of oral health data being derived from relatively small, often clinical samples, with an obvious bias compared with population-/community-based samples. Moreover, the lack of control samples among studies fails to provide contextual understanding of the oral health problems of children with ASD compared to the local child population as a whole.

The objectives of this study were to conduct a community-based oral health survey among preschool children with ASD and to compare the findings with an age- and gender-matched sample, from mainstream preschools. The oral health survey aimed to determine differences in the dental caries experience, gingival health and prevalence of tooth wear, prevalence of dental trauma, prevalence of malocclusion and prevalence of oral mucosal lesions between preschool children with and without ASD in the Hong Kong community. The null hypothesis tested is that there was no significant difference in the dental caries experience, gingival health and prevalence of tooth wear, prevalence of dental trauma, prevalence of malocclusion and prevalence of oral mucosal lesions between preschool children with and without ASD.

Materials and methods

Sample

The sampling frame for this study was the complete list of Special Child Care Centres (SCCC), as identified from the Government Social Welfare Department in Hong Kong Special Administrative Region (HKSAR), China. Of 34 centres identified, 19 SCCCs were selected according to random numbers generated from a computer package. Letters were sent to the school principals to explain the purpose of the study and to invite the centres to participate. In total, 515 children with ASD were identified from the 19 SCCCs and their parent(s)/primary care-givers were invited to participate in the study. An age- (±3 months) and gender-matched sample of preschool children was recruited from mainstream preschools to act as the control group. Approval to conduct the study was sought and obtained from the local Institutional Review Board of Ethics (IRB HKU: UW 11-184).

In considering the sample size requirements for the study, the primary outcome considered was the children’s dental caries experience in their primary dentition (decayed, missing, and filled teeth (dmft) score). Sample size calculation was based on a mean caries experience of 2.40 (SD = 1.52) in the primary dentition, as observed by Altun et al. (2010a). A sample size of 243 was estimated to have 80% power to identify a similar caries experience according to Cochran (1976) formulae. Considering the potential for non-response because of difficulty in conducting an oral health assessment in some uncooperative children with ASD and other reasons of ~50%, the proposed study aimed to invite 500 children with ASD.

Data collection

Prior to commencing the clinical examination, the examiner was trained and calibrated on the clinical assessments at a local preschool by conducting repeat assessments on 25 children. Agreement of the clinical assessments was established to be good (Kappa values > 0.70).

All of the recruited children received a clinical examination by a single trained and calibrated examiner. The clinical examinations took place at the centres (preschools) with the children sitting in a chair. The visual examination was conducted by one examiner using an intra-oral examination mirror with a built-in light-emitting diode (LED) light source (MirrorLite^®). The examination procedures and diagnostic criteria were those recommended in the World Health Organization Oral Health Survey Basic Methods and included assessment of dental caries experience as indicated by the number of sound, decayed, missing (due to caries) and filled surfaces (dmfs) (World Health Organization, 2013).

Eight index teeth, the maxillary right second primary molar (55), maxillary right lateral primary incisor (52), maxillary left primary canine (63), maxillary left first primary molar (64), mandibular left second primary molar (75), mandibular left lateral primary incisor (72), mandibular right primary canine (83) and mandibular right first primary molar (84), were chosen for the assessment of gingival health and tooth wear. Gingival health was assessed by the Simplified Debris Index (Greene and Vermillion, 1964) and the Gingival Index (Löe and Silness, 1963). Tooth wear experience was assessed as being present/absent of ‘loss of enamel involving dentine’ on the index teeth based on the Tooth Wear Index (TWI) criteria (Smith and Knight, 1984).

Trauma was assessed in accordance with the criteria of Andreasen et al. (2007), using the maxillary incisors as the index teeth and classified as being present or absent. In assessing malocclusion, the presence or absence of a deep over-bite, anterior open-bite, increased over-jet, anterior cross-bite and posterior cross-bite was recorded. In addition, the presence or absence of oral mucosal lesions was also recorded (Rioboo-Crespo et al., 2005).

Data analysis

Data were analysed using the statistical package SPSS for Windows 20.0. Differences in mean caries experience (at surface level), plaque index and gingival index scores between children with and without ASD were compared using the Mann−Whitney U-test (a non-parametric equivalent of the t-test for independent samples). A comparison of the prevalence of dental trauma experience, prevalence of tooth wear involving dentine, prevalence of oral mucosal lesions and prevalence of malocclusion between children with and without ASD was assessed using chi-square tests.

Results

Of the 515 children with ASD, 347 participated in the study with parental inform consents. Of the 347 children, 257 (74.1%) children with ASD were able to cooperate with a comprehensive clinical examination. The mean age of the children was 59 ± 10 months (range from 32 to 77 months), of whom 84.4% (217) were males.

Among children with ASD, the mean plaque index score was 0.45 and the mean gingival index score was 0.37 for the index teeth. Children with ASD had lower plaque index scores (p < 0.001) and lower gingival index scores (p < 0.001) than the children without ASD. Almost half (44.4%) of tooth sites of children with ASD had plaque deposits and more than a third of their gingivae showed signs of gingivitis (36.7%). Compared to children without ASD, children with ASD had lower mean plaque index scores (p < 0.001), less surfaces with plaque deposits (p < 0.001), lower mean gingival index score (p < 0.001) and fewer gingival sites with inflammation/gingivitis (p < 0.001; Table 1).

Table 1.

A comparison of the dental caries and gingival health status of preschool children with and without ASD.

	ASD	Non-ASD	p value
Gingival health status, mean (SD)
Plaque index score	0.45 (0.24)	0.60 (0.27)	<0.001**
Presence of plaque (%^a)	44.4 (22.8)	55.7 (23.1)	<0.001**
Gingival index score	0.37 (0.29)	0.51 (0.27)	<0.001**
Presence of gingivitis (%^a)	36.7(27.8)	49.8 (25.9)	<0.001**
Dental caries status, mean (SD)
dmfs	3.73 (9.03)	5.41 (9.18)	0.038*
ds	3.14 (7.66)	4.91 (8.29)	0.012*
ms	0.21 (1.85)	0.09 (1.15)	0.360
fs	0.38 (3.89)	0.41 (1.84)	0.919
Caries experience, % (n)
dmfs > 0	37.0 (95)	52.5 (135)	<0.001**
ds > 0	35.4 (91)	51.4 (132)	<0.001**

ASD: autism spectrum disorders; ds: decayed surfaces; ms: missing surfaces; fs: filled surfaces; dmfs: decayed, missing and filled surfaces; SD; standard deviation.

% of sites

p < 0.05, **p < 0.001 (Mann−Whitney U-test).

In terms of dental caries, children with ASD had less dental caries experiences than children without ASD, with lower mean dmfs (p < 0.05) and lower mean numbers of untreated caries (p < 0.05). Among the children with ASD, 37.0% (95/257) had dental caries experience (dmfs > 0) and 35.4% (91/257) had evidence of untreated decay. For children with ASD, the mean dmfs was 3.73, the mean decayed surfaces (ds) was 3.14, while the mean missing surfaces (ms) was 0.21 and the mean filled surfaces (fs) was 0.38. There was a significant difference in the dental caries experience of the preschool children with and without ASD (p < 0.01; see Table 1).

Children with ASD more frequently had evidence of tooth wear involving dentine than children without ASD (54.1% versus 48.2%); however, there was no statistically significant difference between the two groups (p > 0.05). There was no significant difference in the incidence of dental trauma (p > 0.05), even though children with ASD had a higher percentage of trauma to anterior teeth than those without ASD (22.2% vs 20.6%). In terms of malocclusion, children with ASD more frequently presented with deep over-bite (37.0% vs 31.1%), increased over-jet (18.7% vs 14.8%) and having an anterior cross-bite (14.0% vs 10.9%); however, no statistically significant difference was found between the two groups (p > 0.05). Children with and without ASDs had a similar prevalence of oral mucosal lesions (p > 0.05; Table 2).

Table 2.

A comparison of the prevalence of tooth wear, trauma, malocclusion and oral mucosal health among preschool children with and without ASD.

		ASD, % (n)	Non-ASD, % (n)	p value
Tooth wear^a	Present	54.1 (139)	48.2 (124)	0.186
Trauma to teeth^b	Present	22.2 (57)	20.6 (53)	0.675
Malocclusion
Deep over-bite	Present	37.0 (95)	31.1 (80)	0.172
Anterior open-bite	Present	2.3 (6)	3.9 (10)	0.306
Increased over-jet	Present	18.7 (48)	14.8 (38)	0.245
Anterior cross-bite	Present	14.0 (36)	10.9 (28)	0.343
Posterior cross-bite	Present	0 (0)	0.4 (1)	0.316
Oral mucosal lesions	Present	4.3 (11)	3.9 (10)	0.181

ASD: autism spectrum disorder.

Index teeth: 55, 52, 63, 64, 75, 72, 83, 84.

Maxillary incisors and canines.

p < 0.05, **p < 0.001

Discussion

There is growing recognition and concerns for the oral health of children who require special care, and in particular children with ASD. To date, there is a dearth of community-/population-based studies that have provided comprehensive assessments of the oral health of these children. Hence, there is a dearth of good quality data to base preventive and oral health management strategies. This study benefits from its relative large sample size, being a random sample and having a control group of similar age for comparisons, in addition to a comprehensive assessment of oral health. In the oral health examination, several oral health parameters were considered, including dental caries experience, gingival/periodontal health, tooth wear, malocclusion, dental trauma and oral mucosal conditions, which provide a comprehensive view of the oral health status of children with ASD.

In terms of dental caries, children with ASD had less caries experience, both in terms of prevalence and extent, than children without ASD. Previous reports also suggest a lower caries experience among children with ASD (Loo et al., 2008; Lowe and Lindemann, 1985; Namal et al., 2007). It has been reported that children with ASD have similar plaque pH and saliva buffering capacity as children without ASD (Bassoukou et al., 2009). Nonetheless, it is noted that the caries experience of the children in our study is somewhat higher than preschool children reported in the territory wide on oral health survey of Hong Kong (Oral Health Survey, 2011).

Periodontal health (or markers of) was better among children with ASD. This is in contrast to the other findings (Jaber, 2011; Luppanapornlarp et al., 2010; Orellana et al., 2012). Nonetheless given that almost half of all their teeth had evidence of plaque accumulation, this warrants attention, particularly for children with ASD, as their management in the dental setting is somewhat more complex than that of a normal child.

No significant differences in terms of the prevalence of tooth wear, dental injuries, malocclusion and oral mucosa lesions were observed between the two groups. This is similar to findings of other several clinical studies (Altun et al., 2010b; Fahlvik-Planefeldt and Herrstrom, 2001; Luppanapornlarp et al., 2010; Orellana et al., 2012). Hence, the null hypothesis that there is no significant difference in the dental caries experience, gingival health and prevalence of tooth wear, prevalence of dental trauma, prevalence of malocclusion and prevalence of oral mucosal lesions between preschool children with and without ASD was partially rejected.

It should be acknowledged that this survey was conducted among children with ASD who could ‘cope’ with a comprehensive oral health screening – it was not feasible to conduct an examination among approximately a quarter (n = 90, 25.9%) of the children with ASD. These children may have had poorer oral health, and thus, this issue of non-response bias should be considered when interpreting the findings. Nevertheless, the oral health of the children (ASD and non-ASD) in our study was not good – with a high caries experience, poor oral hygiene and gingivitis. This is of particular concern for children requiring special care, owing to their associated physical, medical, intellectual and social deficits (and most often a combination of all these) that limit their access to oral health care (Nelson et al., 2011). The issue of prevention and oral health promotion for children with ASD warrants particular consideration as there is a dearth of evidence on methods/strategies and/or their effectiveness among such communities and this remains our challenge.

Conclusion

In this community-based epidemiological study in Hong Kong, differences in oral health status exist among preschool children with and without ASDs. Children with ASD tend to have less caries experiences and better oral hygiene and gingival health than children without ASD. Similar experiences of tooth wear, trauma, malocclusion and oral mucosal lesions were observed in children with and without ASD. Nonetheless, the prevalence and extent of oral health problems is considerable and warrants special attention given the challenges of caring for children with ASD in the dental setting.

Footnotes

Acknowledgements

We would like to give many thanks to the children and parents who participated in this study. And we also appreciate the teachers, nurses and social workers in the Special Child Care Centres Hong Kong for their time and efforts spent in this study.

Funding

This project was funded by General Research Fund (17116014) of the Research Grant Council of Hong Kong.

References

Allik

Larsson

Smedje

(2006) Insomnia in school-age children with Asperger syndrome or high-functioning autism. BMC Psychiatry 6: Article 18.

Altun

Guven

Akgun

(2010a) Oral health status of disabled individuals attending special schools. European Journal of Dentistry 4(4): 361–366.

Altun

Guven

Yorbik

(2010b) Dental injuries in autistic patients. Pediatric Dentistry 32(4): 343–346.

American Psychiatric Association (APA) (2000) Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR). 4th ed. Text revision. Washington, DC: APA.

Andreasen

Andersson

(eds) (2007) Textbook and Color Atlas of Traumatic Injuries to the Teeth. 4th ed. Oxford: Blackwell Munksgaard.

Baghdadli

Pascal

Grisi

(2003) Risk factors for self-injurious behaviours among 222 young children with autistic disorders. Journal of Intellectual Disability Research 47(Pt. 8): 622–627.

Barnoy

Najdowski

Tarbox

(2009) Evaluation of a multicomponent intervention for diurnal bruxism in a young child with autism. Journal of Applied Behavior Analysis 42(4): 845–848.

Bassoukou

Nicolau

dos Santos

(2009) Saliva flow rate, buffer capacity, and pH of autistic individuals. Clinical Oral Investigations 13(1): 23–27.

Bradley

Summers

Wood

(2004) Comparing rates of psychiatric and behavior disorders in adolescents and young adults with severe intellectual disability with and without autism. Journal of Autism and Developmental Disorders 34(2): 151–161.

10.

Brereton

Tonge

Einfeld

(2006) Psychopathology in children and adolescents with autism compared to young people with intellectual disability. Journal of Autism and Developmental Disorders 36(7): 863–870.

11.

Cochran

(1976) The role of statistics in national health policy decisions. Am J Epidemiol 104(4): 370–379.

12.

Department of Health (2011) Oral Health Survey 2011. Hong Kong: Department of Health.

13.

Fahlvik-Planefeldt

Herrstrom

(2001) Dental care of autistic children within the non-specialized public dental service. Swedish Dental Journal 25(3): 113–118.

14.

Greene

Vermillion

(1964) The Simplified Oral Hygiene Index. Journal of the American Dental Association 68: 7–13.

15.

Holguin

(2003) Autism of unknown aetiology. Revista de Neurologia 37(3): 259–266 (in Spanish).

16.

Jaber

(2011) Dental caries experience, oral health status and treatment needs of dental patients with autism. Journal of Applied Oral Science 19(3): 212–217.

17.

Johnson

Myers

and American Academy of Pediatrics Council on Children with Disabilities (2007) Identification and evaluation of children with autism spectrum disorders. Pediatrics 120(5): 1183–1215.

18.

Levy

Mandell

Schultz

(2009) Autism. Lancet 374(9701): 1627–1638.

19.

Löe

Silness

(1963) Periodontal disease in pregnancy. I. Prevalence and severity. Acta Odontologica Scandinavica 21: 533–551.

20.

Loo

Graham

Hughes

(2008) The caries experience and behavior of dental patients with autism spectrum disorder. Journal of the American Dental Association 139(11): 1518–1524.

21.

Lowe

Lindemann

(1985) Assessment of the autistic patient’s dental needs and ability to undergo dental examination. ASDC Journal of Dentistry for Children 52(1): 29–35.

22.

Luppanapornlarp

Leelataweewud

Putongkam

(2010) Periodontal status and orthodontic treatment need of autistic children. World Journal of Orthodontics 11(3): 256–261.

23.

Matson

Lovullo

(2008) A review of behavioral treatments for self-injurious behaviors of persons with autism spectrum disorders. Behavior Modification 32(1): 61–76.

24.

Muthu

Prathibha

(2008) Management of a child with autism and severe bruxism: a case report. Journal of the Indian Society of Pedodontics and Preventive Dentistry 26(2): 82–84.

25.

Namal

Vehit

Koksal

(2007) Do autistic children have higher levels of caries? A cross-sectional study in Turkish children. Journal of the Indian Society of Pedodontics and Preventive Dentistry 25(2): 97–102.

26.

Nelson

Getzin

Graham

. (2011) Unmet dental needs and barriers to care for children with significant special health care needs. Pediatric Dentistry 33(1): 29–36.

27.

Orellana

Silvestre

Martinez-Sanchis

(2012) Oral manifestations in a group of adults with autism spectrum disorder. Medicina Oral, Patologia Oral Y Cirugía Bucal 17(3): e415–e419.

28.

Poustka

Lisch

(1993) Autistic behaviour domains and their relation to self-injurious behaviour. Acta Paedopsychiatrica 56(2): 69–73.

29.

Rioboo-Crespo

MdR

Planells-del Pozo

Rioboo-García

(2005) Epidemiology of the most common oral mucosal diseases in children. Medicina Oral, Patología Oral Y Cirugía Bucal 10(5): 376–387.

30.

Shapira

Mann

Tamari

(1989) Oral health status and dental needs of an autistic population of children and young adults. Special Care in Dentistry 9(2): 38–41.

31.

Smith

Roux

Naidoo

(2005) Food choice of tactile defensive children. Nutrition 21(1): 14–19.

32.

Smith

Knight

(1984) An index for measuring the wear of teeth. British Dental Journal 156(12): 435–438.

33.

Stein

Polido

Mailloux

(2011) Oral care and sensory sensitivities in children with autism spectrum disorders. Special Care in Dentistry 31(3): 102–110.

34.

Valicenti-McDermott

McVicar

Rapin

(2006) Frequency of gastrointestinal symptoms in children with autistic spectrum disorders and association with family history of autoimmune disease. Journal of Developmental and Behavioral Pediatrics 27(2 Suppl.): S128–S136.

35.

Weisbrot

Gadow

DeVincent

(2005) The presentation of anxiety in children with pervasive developmental disorders. Journal of Child and Adolescent Psychopharmacology 15(3): 477–496.

36.

Williams

Higgins

Brayne

(2006) Systematic review of prevalence studies of autism spectrum disorders. Archives of Disease in Childhood 91(1): 8–15.

37.

World Health Organization (2013) Oral Health Surveys: Basic Methods. 5th ed. World Health Organization.