Grinding and/or clenching of the teeth, as well as thrusting of the mandible, is considered to be bruxism. Bruxism may occur during the day (‘awake’ bruxism), when psychological issues are thought to be involved, or whilst sleeping (‘sleep’ bruxism), when there appears to be involvement of the central nervous system. External factors, such as medications and substance misuse, may contribute to bruxism. According to the international consensus on the assessment of bruxism, this term is restricted to for patients who clench and/or grind their teeth but are otherwise medically fit and well so the grinding and/or clenching of the teeth in people who have a developmental disorder is not considered to be bruxism.
The aim of this systematic review and meta-analysis was to review the prevalence of tooth grinding and/or clenching in children and adolescents with neurodevelopmental disorders and other developmental anomalies. A secondary aim was to investigate if children and adolescents with neurodevelopmental disorders are more likely to present with grinding and/or clenching than their peers without disabilities.
This review was conducted in accordance with the guidelines of PRISMA and searches were conducted in seven electronic databases (CINAHL EBSCO, Dentistry & Oral Sciences Source EBSCO, Embase, MEDLINE via PubMed, Latin American and Caribbean Health Science Literature (LILACS), PsycINFO, Scopus and Web of Science). Grey literature was searched in Google Scholar (using the first 200 results) and in OpenGrey. There were no time limits or language restrictions on publications. Two calibrated authors independently reviewed the literature and collected cross-checked data using a pre-piloted data extraction sheet. Any disagreements were resolved by consensus or by involving two other authors. A risk of bias assessment was conducted using the Joanna Briggs Institute Critical Appraisal Checklist for Studies Reporting Prevalence Data.
The prevalence of tooth grinding and/or clenching was expressed with absolute or relative frequency (and 95% confidence intervals). The association between teeth grinding and/or clenching and presence of a neurodevelopment disorder was expressed by odds ratio. Statistical synthesis was performed using a meta-analysis. Risk-of-bias plots were made using the robvis tool (a web app for visualizing risk-of-bias assessments) and statistical heterogeneity was assessed using the inconsistency index (I2). The Freeman-Tukey double arcsine transformation was used to calculate overall proportions. Reported grinding and/or clenching was by self-report, proxy report, parent report and questionnaires. Clinically observed grinding and/or clenching was by self-report, proxy report, parent report and/or clinical inspection. Definitive grinding and/or clenching was by electromyography and polysomnography.
- 77 studies were used in the review (from 28 different countries)
- In total: 12,120 individuals were included (7,130 with disability and 4,990 without disability)
- A large proportion of the studies were at high risk of bias
- Primary outcome results were: –
|Neurodevelopmental disorder||Pooled Prevalence of reported clenching and/or grinding (95%CI)||Pooled Prevalence of clinically observed tooth grinding and/or clenching (95%CI)||Pooled Prevalence of definitive tooth grinding and/or clenching (95%CI)|
|Attention Deficit Hyperactivity Disorder (ADHD)||58% (49.5 to 65.6%)
24 studies; 1914 individuals
|Range 5.5% to 55.8%
2 studies; 70 individuals
|39.8% (24.0 to 55.6%)
4 studies; 181 individuals
|Autism Spectrum Disorder (ASD)||50.4% (35.5 to 65.4%)
7 studies; 703 individuals
|57.5% (31.6 to 83.4%)
8 studies; 451 individuals)
|Cerebral Palsy||67.0% (59.2 to 74.8%)
11 studies; 1266 individuals
|71.9% (52.4 to 91.4%)
5 studies; 349 individuals
|Down syndrome||68.2% (59.8 to 76.6%)
9 studies; 600 individuals
|No studies||No studies|
In studies where prevalence of grinding and/or clenching were given in both control and study groups, a meta-analysis was performed as a secondary outcome
|Neurodevelopmental disorder||Odds of presenting with reported grinding and/or clenching compared to control group (95%CI)||Odds of presenting with clinically observed grinding and/or clenching compared to control group (95%CI)|
|Attention Deficit Hyperactivity Disorder (ADHD)||2.84 (2.14 to 3.76)
16 studies; 2,383 individuals
|Autism Spectrum Disorder (ASD)||2.04 (1.34 to 3.11)
4 studies; 630 individuals
|5.22 (3.20 to 8.53)
5 studies; 685 individuals
|Down syndrome||3.75 (1.0 to 13.98)
4 studies; 437 individuals
|Cerebral Palsy||1.61 (0.66 to 3.97)
4 studies; 850 individuals
The prevalence of grinding and/or clenching in children and adolescents with other neurodevelopmental disorders (Angelman syndrome, intellectual disability, vision and hearing-and-voice impairment, Pallister-Killian syndrome, Prader-Willi syndrome, Williams syndrome, Rett syndrome and MECP2 duplication syndrome) are given in the supplementary information
The authors concluded: –
…..due to high heterogeneity and high risk of bias in primary studies, the results should be interpreted with caution. Furthermore, tooth grinding and/or clenching is a relatively frequent condition in individuals with neurodevelopmental disorder and other developmental conditions. Individuals with Down syndrome presented a higher prevalence of tooth grinding and/or clenching, flowed by individuals with cerebral palsy, ADHD, ASD, intellectual disability and Williams syndrome.
The presence of a neurodevelopmental disorder (such as ADHD, ASD, Down syndrome or cerebral palsy) causes a range of cognitive and behavioural issues, which may include a habitual grinding and/or clenching of the teeth. A parafunctional habit of grinding and/or clenching and/or posturing the mandible forward can have a detrimental effect on the oral cavity, including, non-carious tooth surface loss, mucosal trauma and damage to the muscles of mastication and TMJ. The result of this review is that children and adolescents with neurodevelopmental disorder are more likely to have reported and clinically observed grinding and/or clenching of their teeth compared to their peers who do not have a neurodevelopment disorder. However, the review includes studies which are at high risk of bias and have high heterogeneity. Further studies with less bias and heterogeneity are required to provide more robust evidence on the prevalence of grinding and/or clenching amongst those with neurodevelopmental disorders.
Kammer PV, Moro JS, Soares JP, Massignan C, Phadraig CMG, Bolan M. Prevalence of tooth grinding in children and adolescents with neurodevelopmental disorders: A systematic review and meta-analysis. J Oral Rehabil. 2022 Feb 26. doi: 10.1111/joor.13315. Epub ahead of print. PMID: 35218239.
Dental Elf – 22nd September 2017
Dental Elf – 13th September 2017
Lobbezoo F, Ahlberg J, Raphael KG, Wetselaar P, Glaros AG, Kato T, Santiago V, Winocur E, De Laat A, De Leeuw R, Koyano K, Lavigne GJ, Svensson P, Manfredini D. International consensus on the assessment of bruxism: Report of a work in progress. J Oral Rehabil. 2018 Nov;45(11):837-844. doi: 10.1111/joor.12663. Epub 2018 Jun 21. PMID: 29926505; PMCID: PMC628749
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