Oral Health of Children With Attention Deficit Hyperactivity Disorder: Systematic Review and Meta-Analysis

Abstract

Objective: This systematic review investigated the oral health of children with ADHD. Method: A structured search strategy was performed on five electronic databases: SCOPUS, Web of Science, COCHRANE, PubMed, and PsychInfo. Studies were included in the review if they reported clinical oral health outcomes on a population diagnosed with ADHD under the age of 18 years old. Qualitative and quantitative analysis was performed on pooled prevalence and mean/median values for caries, trauma, periodontal problems, and tooth wear. Results: Twenty-seven effective articles were reviewed by two calibrated assessors. Meta-analysis of the results found higher mean number of decayed surfaces, plaque index, and trauma prevalence among children with ADHD. Conclusion: Children with ADHD show increased risk for caries and traumatic dental injuries, and may have poorer oral hygiene compared with children without ADHD. More awareness among clinicians would promote better caries- and trauma-preventive advice and management.

Keywords

ADD/ADHD ADHD attention deficit hyperactivity disorder children oral health

Introduction

ADHD (American Psychiatric Association [APA], 2013) or hyperkinetic disorder (International Statistical Classification of Diseases and Related Health Problems [ICD-10]; World Health Organization, 1992) is a neurobehavioral disorder commonly diagnosed in school-aged children. Symptoms of inattention, hyperactivity, and impulsivity are associated with significant functional impairment and frequently occur with other emotional, behavioral, and learning problems, including oppositional defiant disorder, conduct disorder, depression, anxiety, and learning disabilities (APA, 2013; Larson, Russ, Kahn, & Halfon, 2011).

The literature most commonly refers to the Diagnostic and Statistical Manual (DSM) criteria for the definition of ADHD. The development and use of multiple screening questionnaires and behavioral rating instruments of ADHD symptoms have also proved popular in many epidemiological studies (Brown et al., 2001).

Prevalence rates have varied widely, possibly due to modifications in diagnostic criteria over time. A review of worldwide data estimated a pooled prevalence of 7.1% among children less than 18 years of age (Thomas, Sanders, Doust, Beller, & Glasziou, 2015), which has not increased significantly in recent times (Polanczyk, Willcutt, Salum, Kieling, & Rohde, 2014). Symptoms appear to decrease with age with a prevalence of 2.5% to 4% among the adult population (Simon, Czobor, Balint, Meszaros, & Bitter, 2009; Wilens, Faraone, & Biederman, 2004). Males are diagnosed 3 to 6 times more often than females (Szatmari, Offord, & Boyle, 1989), although it is believed that ADHD may be often underdiagnosed in females due to different clinical manifestations of symptoms (Murray, Naysmith, Liu, & Drummond, 2012).

Children with ADHD may present with additional medical issues, such as sleep disorders, encopresis, and enuresis, or it may be secondary to medical conditions, including traumatic brain injury, fetal alcohol exposure, lead intoxication, premature birth, epilepsy, and tic disorders (Charles, 2010). The symptoms of ADHD are generally treated through behavioral therapy, with or without pharmacological intervention. Medications prescribed are commonly divided into stimulant or nonstimulant drugs. The stimulant medications (such as methylphenidate and amphetamines) have been implicated in adverse oral effects, such as xerostomia and gingival enlargement (Hasan & Ciancio, 2004), although evidence is scant.

The current evidence is controversial regarding the severity and prevalence of dental caries, dental trauma, periodontal disease, and tooth wear among patients with ADHD. Thus, the potential for increased risk of dental disease in this population remains undetermined. Clinical oral health outcomes assessed previously include effects of medications on salivary function (Grooms, Keels, Roberts, & McIver, 2005; Hidas et al., 2013; Hidas et al., 2011) and appetite (Grooms et al., 2005), impaired executive functions and motor coordination affecting oral health behavior (Broadbent, Ayers, & Thomson, 2004; Grooms et al., 2005; Hidas et al., 2011; Murray et al., 2012), and behavior management problems (Atmetlla, Burgos, Carrillo, & Chaskel, 2006; Blomqvist, Holmberg, Fernell, Ek, & Dahllof, 2006), as well as problems with interpersonal interactions that may affect trauma occurrence (Murray et al., 2012; Odoi, Croucher, Wong, & Marcenes, 2002). This study aims to review the oral health status of patients with ADHD to help improve management of affected individuals in the dental setting as well as in the wider public health framework.

Materials and Method

Search Strategy

The search strategy followed Preferred Reporting items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines to identify potentially effective studies from five electronic databases: Pubmed (including Medline), Cochrane, Web of Science, SCOPUS, and PsycINFO from all dates inclusive until November 2016 (Figure 1; Moher, Liberati, Tetzlaff, & Altman, 2010). Medical subject headings (MeSH) terms and key words were developed based on previous systematic reviews of “oral health” (Dai et al., 2015) and “ADHD” (Polanczyk, de Lima, Horta, Biederman, & Rohde, 2007; Table 1). Studies were limited to those published in the English language.

Figure 1.

Search strategy.

Table 1.

MESH Terms and Keywords Used in Search Strategy.

	MESH terms	Keywords
Oral health	“Tooth diseases” “Mouth diseases” “Oral hygiene” “Oral health” “Tooth injuries”	“tooth diseases” “mouth diseases” “oral hygiene” “oral health” “dental deposit” “dental calculus” “plaque accumulation” “periodont” “gingiv” “dental caries” “tooth decay” “tooth demineralization” “tooth decalcification” “tooth loss” “tooth extraction” “probing depth” “bleeding on probing” “gingival haemorrhage” “gingival hemorrhage” “plaque score” “DMF index” “oral clean*” “tooth injuries” “dental injuries” “dental trauma”
ADHD	“Attention deficit with hyperactivity disorder” “Mental disorders” “Attention deficit and disruptive disorders”	“attention deficit with hyperactivity” “mental disorders” “attention deficit and disruptive disorders” “psychiatric disorders” “attention-deficit” “attention deficit/hyperactivity disorder” “hyperactiv” “overactiv” “inattent*” “hyperkinetic disorder” “minimal brain dysfunction”

Note. MESH = medical subject headings.

All terms that begun with root word were included in search.

Duplicates were removed and the remaining “Titles and abstracts” were reviewed. The first batch of 50 abstracts was reviewed by two independent assessors (Y.C. and S.M.P.) to develop criteria for exclusion. These criteria were then applied to the next batch of 100 abstracts, and congruence between assessors was determined. All titles and abstracts were screened to identify “potentially effective studies.”

Full text copies of “potentially effective studies” were obtained and reviewed using the exclusion criteria framework developed by the two previous assessors (Y.C. and S.M.P.) to determine eligibility of “effective studies.” Agreement between assessors was determined using Kappa statistics. Disagreement was resolved by a third assessor (C.M.).

An analysis of “effective studies” according to (a) dental caries, (b) periodontal health status, (c) dental trauma, (d) tooth wear, and (e) other factors was performed. Details of study year, site, sample size, clinical assessment criteria, and outcomes (based on prevalence and mean/median values) for those with and without ADHD were collected, and level of statistical significance recorded. Meta-analysis of the results was performed through the software, Comprehensive Meta-Analysis (CMA) version 2.0 (Biostat, Inc. USA).

Results

The search strategy identified 12,254 references from five databases: 6,146 from Pubmed, 5,057 from SCOPUS (included EMBASE from 1996), 790 from Web of Science, 253 from PsychINFO, and eight from the Cochrane Library. One additional study was found from manual searching of reference lists. The initial screening process (Figure 1) yielded 33 potentially effective references for full-text analysis (Kappa: 0.773). Only observational studies (case-control and cross-sectional studies) that examined oral health status among children (less than 18 years of age) with ADHD were included in the review. Thus, 26 effective papers (Kappa = 0.835) were included for qualitative analysis of the pooled clinical outcomes (based on prevalence and mean/median values) for caries (n = 12), trauma (n = 16), periodontal health (n = 8), and tooth wear (n = 2).

Caries Prevalence

Six case-control studies (Table 2) yielded caries prevalence data (percentage with caries indices > 0 or mean unmet treatment needs scores). Only one study reported data on the primary dentition, and found higher total caries prevalence among children with ADHD (66%) compared with healthy children (43%; p = .05; Grooms et al., 2005). However, the difference was not statistically significant when caries involving dentine was analyzed.

Table 2.

Caries Prevalence and Severity.

Paper and country	ADHD criteria	Case/control (age)	Matching	Caries prevalence (%)	Caries M (SD)	Other values: M (SD)
Atmetlla, Burgos, Carrillo, and Chaskel (2006) (Columbia)	Referred from Psychiatric Department, then SNAP-IV and ADHDT	36 ADHD cases (5-13 years) • no medication on day of exam	No	N/A	DMFT/deft: 6.8*
Atmetlla, Burgos, Carrillo, and Chaskel (2006) (Columbia)		47 medically healthy controls (5-13 years)	No	N/A	DMFT/deft: 10.0
Bimstein, Wilson, Guelmann, and Primosch (2008) (The United States)	ADHD medications	25 ADHD cases (90.4 ± 39.6 months)• all medicated	No	Unmet treatment needs^† 76.9 (36.9)	DS: 8.1 (12.1)FS: 1.3 (3.0)
	ADHD medications	127 medically healthy controls (88.2 ± 43.6 months)	No	81.6 (30.8)	DS: 6.5 (7.1)FS: 1.6 (3.8)
Blomqvist, Ahadi, Fernell, Ek, and Dahllof (2011) (Sweden)	DSM-IV	32 ADHD cases (17 years)	Yes: age	DMFS > 0: 94%*	DS: 2.0 (2.2)** DMFS: 6.1 (4.3)DMFT: 4.6 (2.8)
Blomqvist, Ahadi, Fernell, Ek, and Dahllof (2011) (Sweden)	DSM-IV	55 screen-negative controls (17 years)	Yes: age	DMFS > 0: 71%	DS: 0.9 (1.4)DMFS: 4.4 (4.9)DMFT: 3.6 (3.6)
Blomqvist, Holmberg, Fernell, Ek, and Dahllof (2007) (Sweden)	DSM-IV	21 ADHD cases (13 years)• 2 methylphenidate; 1 amphetamine	Yes: age	DMFS > 0: 62%	DS: 1.0 (2.2)DMFS: 2.8 (4.0)
	DSM-IV	79 screen-negative controls (13 years)	Yes: age	DMFS > 0: 52%	DS: 0.7 (1.5)DMFS: 2.2 (3.2)
Blomqvist, Holmberg, Fernell, Ek, and Dahllof (2006) (Sweden)	DSM-IV	25 ADHD cases (11 years)	Yes: age	N/A	DMFS: 2.0 (3.0)* DS: 1.7 (3.6)*
	DSM-IV	58 screen-negative controls (11 years)	Yes: age		DS: 0.5 (0.9)DMFS: 1.0 (1.5)
Broadbent, Ayers, and Thomson (2004) (New Zealand)	ADHD positive medical history	128 high caries load cases (11-13 years)• DMFT > 5• 11 ADHD cases (8 medicated)• 128 low caries load controls (11-13 years)• DMFT ≤ 4• 3 ADHD cases (1 medicated)	Yes: gender, school decile, ethnicity, age	DMFT > 5: OR = 10.2* [95% CI 1.3, 91.8]	N/A
Chandra, Anandakrishna, and Ray (2009) (India)	Connor’s questionnaire	40 ADHD cases (6-14 years)medicated and non-medicated	Yes: age, gender, SES	N/A	defs: 8.9 (4.9)** DMFS: 1.1 (1.2)
Chandra, Anandakrishna, and Ray (2009) (India)	Connor’s questionnaire	40 medically healthy controls (6-14 years)	Yes: age, gender, SES	N/A	defs: 2.9 (2.8)DMFS: 0.7 (1.0)
Grooms, Keels, Roberts, and McIver (2005) (The United States)	DSM-IV	38 ADHD cases (6-11 years)• 30 methylphenidate• 7 dextroamphetamine• 12 nonstimulant medication	Yes: age, race, gender, SES	d(1)mfs > 0: 66%d(3)mfs > 0: 50%	dmfs: 5.8 (8.8)DMFS: 0.9 (2.0)	d(1)s: 1.0 (2.3)* D(1)S: 0.6 (1.9)*
	DSM-IV	38 medically healthy controls (6-11 years)	Yes: age, race, gender, SES	d(1)mfs > 0: 43%d(3)mfs > 0: 35%	dmfs: 5.8 (10.8)DMFS: 0.6 (1.5)	d(1)s: 0.3 (1.2)D(1)S: 0 (0)
Hidas et al. (2011) (Israel)	DSM-IV	31 ADHD1 cases (5.9-16.7 years)• nonmedicated	No	N/A	DMFT/dmft: 2.6 (2.3)
		30 ADHD2 cases (6.7-17.2 years)• methylphenidate medication			DMFT/dmft: 4.3 (3.8)
		30 medically healthy controls (6.0-17.8 years)			DMFT/dmft: 4.1 (3.6)
Kohlboeck et al. (2013) (Germany)	SDQ	161 cases (9.8-11.8 years)• borderline or abnormal HA/IA values• 16 methylphenidate or atomoxetine	Yes: age	DT > 0: 1.9%D(1)MFS > 0: 57.1%*	DMFT: 0.3 (0.7)DMFS: 0.4 (1.0)	D(1)S: 2.0 (2.8)** FT: 0.2 (0.7)FS: 0.3 (0.9)
Kohlboeck et al. (2013) (Germany)	SDQ	965 controls (9.8-11.8 years)• normal HA/IA values• no ADHD medication	Yes: age	DT > 0: 2.3%D(1)MFS > 0: 47.0%	DMFT: 0.3 (0.8)DMFS: 0.4 (1.2)	D(1)S: 1.4 (2.1)FT: 0.3 (0.8)FS: 0.4 (1.2)
Williamson, Oueis, Casamassimo, and Thikkurissy (2008) (The United States)	CBC	60 cases (30-60 months)CA: requiring general anaesthesia for dental treatment	No	N/A	ADHD scores: 54.8 (7.1)* Externalizing problem scores: 49.3 (10.7)*
	CBC	60 controls (30-60 months)medically healthyCF	No	N/A	ADHD scores: 52.2 (4.4)Externalizing problem scores: 44.7(9.4)

Note. SNAP-IV = Swanson, Nolan, and Pelham Questionnaire; ADHDT = Attention Deficit Hyperactivity Disorder Test; defs = decayed, extracted, filled surfaces for primary dentition; dmft = decayed, missing, filled teeth for primary dentition; DMFT = decayed, missing, filled teeth; DMFS = decayed, missing, filled surfaces; DS = decayed surfaces; D(I)S = decayed incipient surfaces; FT = filled teeth; FS = filled surfaces; DSM-IV = Diagnostic and Statistical Manual of Mental Disorders (4th ed.; American Psychiatric Association, 1994); OR = odds ratio; CI = confidence interval; SDQ = Strength and Difficulties Questionnaire (parent-reported); HA = hyperactivity; IA = inattention; DT =decayed teeth; CBC = Child Behaviour Checklist; CA = caries active; CF = caries free; CTQ = Conner’s Teacher Questionnaire; ARS = Attention Deficit/Hyperactivity Disorders Rating Scale; CRS-Revised = Connor’s Rating Scale–Revised; CPRS-RS = Conner’s Parent Rating Scale–Revised (Short form); SES = socio-economic status.

†

M (SD) value.

p < 05. **p < .01.

Five studies reported on caries prevalence in the permanent dentition with three studies reporting significantly higher caries prevalence in children with ADHD or higher than average hyperactivity scores (Blomqvist, Ahadi, Fernell, Ek, & Dahllof, 2011; Broadbent et al., 2004; Kohlboeck et al., 2013). In one study, significance was only found when incipient enamel caries was included (Kohlboeck et al., 2013). The meta-analysis (fixed effect model: heterogeneity Q = 3.218; df = 3, p > .05; Figure 2) showed that children with ADHD have more than one and a half times odds for having caries compared with children without ADHD (odds ratio = 1.621; 95% CI = 1.20, 2.179).

Figure 2.

Difference in caries prevalence (fixed effect).

Caries Extent

One study on primary teeth revealed a significantly higher mean caries in children with ADHD (Chandra, Anandakrishna, & Ray, 2009), while the other observed that significance was found only for incipient enamel caries (Grooms et al., 2005). The meta-analysis of these two studies did not show any significant effects (standardized mean difference = 0.748, 95% CI = −0.725, 2.221; Figure 3). Two other studies examined the combined caries experience of both primary and permanent teeth (Decayed, Missing, Filled Teeth [DMFT]/ decayed, extracted, filled primary teeth [deft] indices) but found conflicting results. One reported significantly lower decay levels in children with ADHD (Atmetlla et al., 2006), while the other found no significant differences (Hidas et al., 2011).

Figure 3.

Difference in mean DMFT/deft (random effect).

Despite only one study reporting significantly higher caries experience in permanent teeth (mean DMFS/DMFT) among children with ADHD (Blomqvist et al., 2006), four studies found significantly more decayed surfaces or teeth (DS/DT; Blomqvist et al., 2011; Blomqvist et al., 2006; Grooms et al., 2005; Kohlboeck et al., 2013). Both the meta-analysis of difference in mean DMFT (Figure 4) and mean DMFS reported nonsignificant effects (Figure 5). However, a significantly higher mean DS (standardized mean difference = 0.314, 95% CI = 0.179, 0.449) was found among children with ADHD in the meta-analysis (fixed effect model: heterogeneity Q = 3.932, df = −4, p > .05), which included results for incipient carious surfaces (Figure 6).

Figure 4.

Difference in mean DMFT (fixed effect).

Figure 5.

Difference in mean DMFS (fixed effect).

Figure 6.

Difference in mean DS (fixed effect).

There were two studies that also reported significant associations in higher caries levels among children with ADHD and externalizing behavior problems (Broadbent et al., 2004; Williamson, Oueis, Casamassimo, & Thikkurissy, 2008). Conversely, children with caries also showed a significantly higher proportion of externalizing problems (which included hyperactivity symptoms) and attention deficit/hyperactivity issues (Williamson et al., 2008).

Dental Trauma

The prevalence of traumatic dental injuries ranged from 2.30% to 42% in children with ADHD (Table 3). A meta-analysis of five studies, including two separate sample groups from one study (random effect model: heterogeneity Q = 18.482, df = 5, p = .002) showed that children with ADHD had 1.5 times higher odds of dental trauma compared with children without ADHD (95% CI = 1.169, 2.094; Figure 7).

Table 3.

Dental Trauma Prevalence.

Paper and country	ADHD criteria	Case/control (age)	Matching	Dental trauma prevalence (M ± SD or %)	Notes
Altun, Guven, Akgun, and Acikel (2012) (Turkey)	Cases referred from psychiatric department	97 ADHD cases (7-15 years)	Yes: gender, age	17.5%	Clinical exam(WHO classification)
Altun, Guven, Akgun, and Acikel (2012) (Turkey)	Cases referred from psychiatric department	97 medically healthy controls (7-15 years)	Yes: gender, age	16.5%	Clinical exam(WHO classification)
Atmetlla, Burgos, Carrillo, and Chaskel (2006) (Columbia)	Referred from psychiatric department, then SNAP-IV and ADHDT	36 ADHD cases (5-13 years)• no medication on day of exam	No	62.2% hospital*	Parental report
Atmetlla, Burgos, Carrillo, and Chaskel (2006) (Columbia)		47 medically healthy controls (5-13 years)	No	37.8% hospitalLower % traumaNot explicitly dental trauma	Parental report
Avsar, Akbas, and Ataibis (2009) (Turkey)	DSM-IV	247 ADHD cases (7-16 years)• no previous therapy• no medicationsno controls	N/A	31.6%	Clinical exam(WHO classification)
Bani, Bodur, and Kapci (2015) (Turkey)	CRS-Revised	80 dental trauma cases (7-15 years)• traumatic dental injury in previous 2 weeks	No	HA: OR = 1.7 (males only)^a HA symptoms: 64.3% (males)Wald^d χ² = 5.0, df = 1*	Clinical exam(WHO classification)
Bani, Bodur, and Kapci (2015) (Turkey)	CRS-Revised	80 control (7-15 years)• no dental injury, but have other dental problems, for example, caries• medically healthy	No	HA symptoms: 44% (males)	Clinical exam(WHO classification)
Bimstein, Wilson, Guelmann, and Primosch (2008) (The United States)	ADHD medications	25 ADHD cases (90.4 ± 39.6 months)• all medicated	No	26%**	Retrospective data from patient’s dental records:Parental reports
	ADHD medications	127 medically healthy controls (88.2 ± 43.6 months)	No	6%
Blomqvist, Holmberg, Fernell, and Dahllof (2004) (The United States)	DSM-IV	128 ADHD cases (1-10 years)	No	28%	Retrospective data from patient’s dental records
	DSM-IV	131 screen-negative controls (1-10 years)	No	34%	Retrospective data from patient’s dental records
Herguner, Erdur, Basciftci, and Herguner (2015) (Turkey)	CPRS-R	55 dental trauma cases (7-16 years)	Yes: gender, age	HA score: 4.1 ± 3.7* Correlation r = 0.24** with past history of dental trauma and HA	Clinical exam(WHO classification)
Herguner, Erdur, Basciftci, and Herguner (2015) (Turkey)	CPRS-R	55 control (7-16 years)• no dental trauma	Yes: gender, age	HA score: 2.7 ± 2.6	Clinical exam(WHO classification)
Katz-Sagi, Redlich, Brinsky-Rapoport, Matot, and Ram (2010) (Israel)	ADHD medication (methylphenidate)	24 ADHD cases (5-12 years)• medicated	No	29.1%*	Clinical exam (author’s own classification)+ Parental reports
	ADHD medication (methylphenidate)	22 medically healthy controls (5-12 years)	No	4.5%
Kohlboeck et al. (2013) (Germany)	SDQ	161 cases (9.8-11.8 years)• borderline or abnormal HA/IA values• 16 methylphenidate or atomoxetine	Yes: age	Mean number TDI: 1.9 ± 0.3	Clinical exam(WHO classification)
Kohlboeck et al. (2013) (Germany)	SDQ	965 controls (9.8-11.8 years)• normal HA/IA values• no ADHD medication	Yes: age	Mean number TDI: 1.9 ± 0.3	Clinical exam(WHO classification)
Lalloo (2003) (The United Kingdom)	SDQ	1,057 cases (4-15 years)• 417 borderline HA• 640 high HA values	No	High HA: 2.3%* (OR = 2.0 [1.1, 3.5])Borderline HA: 1.3%* (OR = 2.6 [1.4-4.9])	Parental ± child’s report
Lalloo (2003) (The United Kingdom)	SDQ	4,034 controls (4-15 years)• normal HA values	No	1.2%	Parental ± child’s report
Mota-Veloso et al. (2016) (Brazil)	SNAP-IV	115 dental trauma cases (7-12 years)115 control (7-12 years)• no traumatic dental injuries• no systemic disorders	Yes: age, gender	HA: OR = 2.3 (1.1-4.9)*^b	Clinical exam(O’Brien criteria)
Odoi, Croucher, Wong, and Marcenes (2002) (The United Kingdom)	SDQ	85 dental trauma cases (7-15 years)• trauma within 12 months85 control (7-15 years)• no traumatic dental injuries	Yes: age, gender	HA: OR =1.1 (0.4-2.8)^c	Clinical exam
Ramchandani, Marcenes, Stansfeld, and Bernabe (2016) (The United Kingdom)	SDQ–self-reported	87 cases (15-16 years)• HA in top decile	No	17%HA: OR = 0.8 (0.4-1.5)^d	Clinical exam(WHO classification)
	SDQ–self-reported	707 control (15-16 years)• normal HA values	No	15%	Clinical exam(WHO classification)
Sabuncuoglu, Taser, and Berkem (2005) (Turkey)	DSM-IV + CTQ	235 ADHD cases (8-17 years)• 95 with psychiatric comorbidities	No	12.8%** (OR = 17.4 [4.1-73.6])	Parental + child’s report
Sabuncuoglu, Taser, and Berkem (2005) (Turkey)	DSM-IV + CTQ	240 non-ADHD controls (8-17 years)• 33 with psychiatric comorbidities	No	0.8%	Parental + child’s report
Staberg, Noren, Johnson, Kopp, and Robertson (2014) (Sweden)	DSM-IV	31 ADHD cases (5-19 years)• 26 with psychiatric comorbidities• 28 medicated	N/A	42%	Parental report
Thikkurissy, McTigue, and Coury (2012) (The United States)	ARS-IV	88 dental trauma cases (6-18 years)• trauma within 6 months	No	HI/IA symptoms: 21%ADHD diagnosis: 18%	Clinical exam
Thikkurissy, McTigue, and Coury (2012) (The United States)	ARS-IV	73 controls (6-18 years)• no traumatic dental injuries	No	HI/IA symptoms: 18%ADHD diagnosis: 10%	Clinical exam

Note. WHO = World Health Organization; SNAP-IV = Swanson, Nolan, and Pelham Questionnaire; ADHDT = Attention Deficit Hyperactivity Disorder Test; DSM-IV = Diagnostic and Statistical Manual of Mental Disorders (4th ed.; American Psychiatric Association, 1994); CRS-R = Revised Connor’s Rating Scale–Revised; OR = odds ratio; CPRS-R = Conner’s Parent Rating Scale–Revised; SDQ = Strength and Difficulties Questionnaire (parent-reported); HA = hyperactivity; IA = inattention; CI = confidence interval; CTQ = Conner’s Teacher Questionnaire; ARS = Attention Deficit/Hyperactivity Disorders Rating Scale.; TDI = traumatic dental injury.

Hyperactivity symptoms only found to be risk factor for males, not females.

Adjusted for “type of school” and overjet.

Fully adjusted by problems behavior, parent’s level of education, size of overjet, and type of lip coverage.

Adjusted for gender, age, ethnicity, parental employment, overjet.

p < .05. **p < .01.

Figure 7.

Difference in trauma prevalence (random effect).

Two cross-sectional studies indicated a high dental trauma prevalence (31.6%-42%) in a population of ADHD children but made no comparisons to controls (Avsar, Akbas, & Ataibis, 2009; Sabuncuoglu, Taser, & Berkem, 2005). A significantly higher hospital admission was reported for children with ADHD, although it was not clear whether the trauma experience included dental injuries (Atmetlla et al., 2006). Furthermore, some studies have shown a higher prevalence of diagnosed ADHD or symptoms of hyperactivity/inattentiveness among children who had experienced a traumatic dental injury (Bani, Bodur, & Kapci, 2015; Herguner, Erdur, Basciftci, & Herguner, 2015; Mota-Veloso et al., 2016), while other studies reported no such trend (Odoi et al., 2002; Thikkurissy, McTigue, & Coury, 2012).

Oral Hygiene—Plaque Index

Five case-control studies (Table 4) assessed plaque levels using the Löe and Silness method (Silness & Loe, 1964) and the O’Leary index (O’Leary, Drake, & Naylor, 1972). A meta-analysis (random effect model: heterogeneity Q =18.311, df = 2, p < .001) was performed for three studies (Hasan & Ciancio, 2004; Hidas et al., 2011; Kohlboeck et al., 2013) and found significant effects of higher mean plaque index scores among children with ADHD (standardized mean difference = 0.758, 95% CI = 0.033, 1.483; Figure 8).

Table 4.

Periodontal Health.

Paper and country	ADHD criteria	Case/control (age)	Matching	Oral hygiene: Plaque index(M ± SD or %)	Gingival Bleeding Index/inflammation(M ± SD or %)	Other periodontal markers(M ± SD or %)
Bimstein, Wilson, Guelmann, and Primosch (2008) (USA)	ADHD medications	25 ADHD case (90.4 ± 39.6 months)• all medicated	No	Prevalence: 83%	Prevalence: 73%	Prevalence: Calculus 57%
Bimstein, Wilson, Guelmann, and Primosch (2008) (USA)	ADHD medications	127 medically healthy controls (88.2 ± 43.6 months)	No	Prevalence: 86%Löe & Silness (PI)	Prevalence: 65%Löe & Silness (GI)	Prevalence: Calculus: 30%
Blomqvist, Ahadi, Fernell, Ek, and Dahllof (2011) (Sweden)	DSM-IV	32 ADHD cases (17 years)	Yes: age		35% ± 39%*
Blomqvist, Ahadi, Fernell, Ek, and Dahllof (2011) (Sweden)	DSM-IV	55 screen-negative controls (17 years)	Yes: age		16% ± 24%Axelsson & Lindhe
Blomqvist, Holmberg, Fernell, Ek, and Dahllof (2007) (Sweden)	DSM-IV	21 ADHD cases (13 years)• 2 methylphenidate; 1 amphetamine	Yes: age		7.0% ± 5.4% [95% CI 4.5, 9.4]
	DSM-IV	79 screen-negative controls (13 years)	Yes: age		8.1% ± 6.3% [95% CI 6.7, 9.5]Axelsson & Lindhe
Blomqvist, Holmberg, Fernell, Ek, and Dahllof (2006) (Sweden)	DSM-IV	25 ADHD cases (11 years)	Yes: age		4.3% ± 4.5%
	DSM-IV	58 screen-negative controls (11 years)	Yes: age		4.1% ± 4.5%Axelsson & Lindhe
Chandra, Anandakrishna, and Ray (2009) (India)	Connor’s questionnaire	40 ADHD cases (6-14 years)medicated and nonmedicated40 medically healthy controls (6-14 years)	Yes: age, gender, SES	Higher* (Data not given)O’Leary (PI)
Hasan and Ciancio (2004) (USA)	ADHD medication (dextroamphetamine)	20 ADHD cases (6-14 years)• medicated	No	1.1 ± 0.1	0.9 ± 0.1	Gingival enlargement: 1.2 ± 0.2**
Hasan and Ciancio (2004) (USA)	ADHD medication (dextroamphetamine)	20 medically healthy controls (6-14 years)• no medications	No	0.9 ± 0.1Löe & Silness (PI)	0.6 ± 0.1Turesky (Modified GI)	Gingival enlargement: 0.6 ± 0.1
Hidas et al. (2011) (Israel)	DSM-IV	31 ADHD1 cases (5.9-16.7 years)• nonmedicated	No	1.9 ± 0.7** (ADHD 1 + 2)
		30 ADHD2 cases (6.7-17.2 years)1. methylphenidate medication
		30 medically healthy controls (6.0- 17.8 years)		1.4 ± 0.6Löe & Silness (PI)
Kohlboeck et al. (2013) (Germany)	SDQ	161 cases (9.8-11.8 years)borderline or abnormal HA/IA values16 methylphenidate or atomoxetine	Yes: age	2.4 ± 1.8* (n.s. in fully adjusted models)	2.04 ± 2.10
Kohlboeck et al. (2013) (Germany)	SDQ	965 controls (9.8-11.8 years)normal HA/IA valuesno ADHD medication	Yes: age	2.0 ± 1.8Löe & Silness (PI)	1.80 ± 2.02Muhlemann & Son (GSB^)

Note. DSM-IV = Diagnostic and Statistical Manual of Mental Disorders (4th ed.; American Psychiatric Association, 1994); CI = confidence interval; HA = hyperactivity; IA = inattention; SES = socio-economic status; PI = plaque index; GSB = gingival sulcus bleeding; GI = gingival index.

p < .05. **p < .01.

Figure 8.

Difference in mean plaque index (random effect).

Periodontal Disease

Despite the tendency of children with ADHD to have higher levels of gingival inflammation, only one case-control study reported significantly higher results in 17-year-old adolescents with ADHD (Blomqvist et al., 2011; Table 4). Three of the studies used the Axelsson and Lindhe method to assess gingival inflammation (Axelsson & Lindhe, 1975), while the others used the Löe and Silness gingival index (Silness & Loe, 1964), Turesky’s modified gingival index (Turesky, Gilmore, & Glickman, 1970), or gingival sulcus bleeding index (Muhlemann & Son, 1971). The meta-analysis for difference in mean gingival index scores showed no significant differences between children with ADHD and those without ADHD.

No significant difference in calculus was detected (Bimstein, Wilson, Guelmann, & Primosch, 2008), but one study revealed significantly higher levels of gingival enlargement (Hasan & Ciancio, 2004) in children with ADHD who were medicated.

Tooth Wear

Only two case-control studies provided data on clinical measures of tooth wear, and both reported significantly more tooth wear facets among children with ADHD (Atmetlla et al., 2006; Malki, Zawawi, Melis, & Hughes, 2004; Table 5). One study showed that children taking CNS (central nervous system) stimulant medication had significantly greater signs of tooth wear than both nonmedicated children with ADHD and healthy controls (Malki et al., 2004).

Table 5.

Tooth Wear.

Paper and country	ADHD criteria	Case/control (age)	Matching	Tooth wear/ attrition (M ± SD or %)	Other information
Atmetlla, Burgos, Carrillo, and Chaskel (2006) (Columbia)	Referred from Psychiatric Department, then SNAP-IV and ADHDT	36 ADHD cases (5-13 years)• no medication on day of exam	No	1.3* facets (0-9 affected teeth)	Physiological attrition (n.s.)
Atmetlla, Burgos, Carrillo, and Chaskel (2006) (Columbia)		47 medically healthycontrols (5-13 years)	No	0.5 facets (0-5 affected teeth)Unreported index	Physiological attrition (n.s.)
Malki, Zawawi, Melis, and Hughes (2004) (The United States)	Positive medical history	30 ADHD cases (5-15 years)• 24 medicated	Yes: age, gender	6.1 ± 1.2 teeth Med: 7.2 ± 1.4 teeth No med: 1.8 ± 0.8 teeth	ADHD + med: 7.2 ± 1.4 teeth** ADHD (no med): 1.8 ± 0.8 teethCNS stimulants: 8.9 ± 1.5 teeth* Nonstimulant: 3.0 ± 0.9 teeth
Malki, Zawawi, Melis, and Hughes (2004) (The United States)	Positive medical history	30 medically healthy controls (5-15 years)	Yes: age, gender	1.5 ± 0.5 teethUnreported index

Note. SNAP-IV = Swanson, Nolan, and Pelham Questionnaire; ADHDT = Attention Deficit Hyperactivity Disorder Test; CNS = central nervous system.

p < .05. **p < .01.

Discussion

Studies were screened with a reasonable level of agreement between reviewers. Both case-control and cross-sectional designs were included due to the small number of studies involved. The exclusion of non-English publications may have contributed to publication bias; however, attempts to minimize the effect were made with the screening of multiple databases.

Due to the small sample sizes and range of ages from 30 months old to 19 years of age, it was challenging to compare data from various combinations of primary, mixed, and permanent dentition stages. Furthermore, many of the studies did not include a confirmed medical diagnosis of ADHD. Instead, some authors described the use of ADHD medication or screening questionnaires and behavioral rating scales to identify case patients with hyperactivity or inattention problems. The inconsistent diagnostic criteria likely affected the validity of the analysis as some ADHD patients, especially those receiving medical treatment, may screen negatively for behavioral problems in larger population studies. Alternatively, some subjects who screen positively may not fulfill the criteria for diagnosis of ADHD.

Caries

There has been growing interest in the caries status among children with ADHD, particularly when symptoms may impact oral hygiene practices, and from potential side effects of medications on salivary function and appetite (Grooms et al., 2005; Hidas et al., 2013; Hidas et al., 2011). In addition, the higher prevalence of behavior management problems among this population in the dental office may adversely affect the number of teeth with untreated decay (Atmetlla et al., 2006; Blomqvist et al., 2006).

The meta-analysis of caries prevalence studies showed significantly higher odds for caries prevalence among children with ADHD. However, results were inclusive of a broad age group from 6 to 17 years of age and did not delineate effects on different stages of dentition. The higher prevalence of incipient caries in the primary teeth of children with ADHD compared with healthy controls may indicate a reversibility of lesion progression in this age group (Grooms et al., 2005). The meta-analysis did not show significantly higher severity of enamel caries in the primary dentition, and was limited in interpretation by the inclusion of only two studies.

In the permanent dentition, the majority of case-control studies reported significantly higher caries prevalence in young adolescents with ADHD or symptoms of hyperactivity (Blomqvist et al., 2011; Broadbent et al., 2004; Kohlboeck et al., 2013). In these studies, significance was again confined to incipient enamel caries (Kohlboeck et al., 2013), or occurred in older age groups (17 years of age; Blomqvist et al., 2011). The results may indicate that caries experienced by children with ADHD is predominantly reversible in their earlier years up to young adolescence, and can be prevented by early intervention with caries preventive strategies.

Many studies reported no differences in caries experience for permanent teeth, which was confirmed by the results of the meta-analysis; however, some studies included children in the mixed dentition stages (Chandra et al., 2009; Grooms et al., 2005; Kohlboeck et al., 2013). One study that found higher caries mean scores in permanent teeth in fact assessed children aged 11 years old (Blomqvist et al., 2006). When the caries scores for both permanent and primary teeth were combined, the lower and nonsignificant caries scores among ADHD subjects (Atmetlla et al., 2006; Hidas et al., 2011) may be explained by the possible higher accessibility of children with ADHD to health care services .

Among children with ADHD, the meta-analysis showed significantly higher levels of decayed surfaces, and it is important to note studies were predominantly conducted on children in the mixed dentition stage. The results are indicative of a higher caries risk for permanent teeth among ADHD subjects, even during the earlier years in mixed dentition stage.

Other studies compared the proportion of ADHD subjects in high or low caries risk groups (Broadbent et al., 2004; Williamson et al., 2008). Due to the different grouping criteria of subjects and broad age range, comparisons of results should be interpreted with caution. As the majority of studies included children in the mixed dentition stage, it is difficult to infer any significant differences (or lack of) in caries experience for children with ADHD during the primary dentition or permanent dentition stages.

Trauma Prevalence

Traumatic injuries has long been associated with children diagnosed with ADHD and is often attributed to problems with peer relationships (Odoi et al., 2002), risk of physical abuse (Waldman, Swerdloff, & Perlman, 2000), and motor coordination issues (Fliers et al., 2008). The association of ADHD with dental traumatic injuries, however, is less established, and is not helped by the variety in assessment technique, including clinical indices, parental or patient reports, and retrospective data from patient records.

Results were difficult to compare because of different case selection criteria (e.g., medication use, behavior questionnaire, psychiatric referrals), as well as variations in the reporting of trauma outcomes, which included odds ratio, prevalence proportions, and mean number of teeth affected. Also, many studies described only hyperactivity symptoms or included psychiatric comorbidities. One study (Bani et al., 2015) found significantly higher odds for dental trauma with males with ADHD only. The meta-analysis confirmed that children with ADHD had 1.5 higher odds in experiencing dental trauma than non-ADHD controls. Thus, clinicians should be aware of the increased risk of traumatic dental injuries among children with ADHD and provide trauma-preventive advice or management accordingly.

Periodontal Health

The meta-analysis showed significantly higher plaque scores among children with ADHD. Interestingly, children prescribed ADHD medications do not seem to have similar levels of poor oral hygiene (Bimstein et al., 2008; Hasan & Ciancio, 2004). Subject inclusion criteria again varied in medication use among ADHD children as well as in ADHD assessment.

Gingival health was also assessed using a variety of indices among the six case-control studies included in the review. Data were reported as prevalence among sample groups, proportion of sites affected, and mean gingival bleeding scores. The meta-analysis did not identify any significant differences in gingival inflammation between children with or without ADHD, despite obvious differences in plaque levels.

Studies that included additional markers of periodontal disease also found no significant differences in presence of calculus (Bimstein et al., 2008). One study observed significant levels of gingival enlargement in ADHD children who were medicated, which surprisingly could not be attributed to poor oral hygiene practices (Hasan & Ciancio, 2004). More research is required to further clarify these findings. The generalized limited data on periodontal outcomes may be explained by the young ages of the study populations.

Tooth Wear

Although many studies reported on the prevalence of bruxism, only two case-control studies provided data on clinical measures of tooth wear. Since previous studies have refuted the association between reported bruxism and tooth wear (Seligman, Pullinger, & Solberg, 1988), only studies with clinical data were included in the review. Both reported significantly more tooth wear facets among children with ADHD (Atmetlla et al., 2006; Malki et al., 2004) although a meta-analysis could not be performed due to differences in data reporting systems. The use of CNS stimulant medication may be associated with significantly greater levels of tooth wear (Malki et al., 2004), but further research is required to confirm.

Limitations

Unfortunately, meta-analysis of the results could only be performed on a limited number of studies due to the nature of the reported data, including methodological differences. The broad age range among sample groups also hampered interpretation of the data. The need for standardized indices is recommended for better comparison of results.

It is recommended that further research of standardized methodology be conducted to clarify the oral health status of patients with ADHD and the effect of the different medications. Not only will this aid dental practitioners in better managing the oral health of these individuals, but it would also be beneficial from a public health perspective. This is particularly relevant among adolescents with ADHD, in the permanent dentition stage, which are currently under-represented in the literature. The clarification of dental disease burden in this age group can have implications for future restorative needs during adulthood.

Conclusion

Meta-analysis of pooled clinical data indicates significantly higher number of decayed surfaces (including incipient enamel caries) in permanent teeth, higher plaque scores, and higher dental trauma risk among children with ADHD. The review highlights the importance of incorporating dental preventive advice when treating children with ADHD, particularly in terms of caries and trauma prevention.

Footnotes

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

Author Biographies

Yvonne C. Y. Chau completed her postgraduate research on oral health outcomes among children with ADHD. She now works as a staff specialist at the Department of Pediatric Dentistry, Sydney Dental Hospital, Australia.

Si-Min Peng is a part-time clinical lecturer in pediatric dentistry, Faculty of Dentistry, the University of Hong Kong.

Colman P. J. McGrath is a clinical professor in dental public health, Faculty of Dentistry, the University of Hong Kong.

Cynthia K. Y. Yiu is a clinical professor in pediatric dentistry, Faculty of Dentistry, the University of Hong Kong.

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