Risk of subsequent attention‐deficit/hyperactivity disorder among children and adolescents with amalgam restorations: A nationwide longitudinal study

Abstract

Objectives: Dental amalgam has been used as a common restorative material since the 1800s, but concerns have been raised regarding its purported neuropsychological effects due to the neurotoxicity of mercury. In this study, a nationwide population-based database was employed to investigate the association of dental amalgam restoration with the risk of attention-deficit/hyperactivity disorder (ADHD). Results: In total, 2073 people (2.4%) received an ADHD diagnosis during the study period, yielding an incidence rate of 32.4 per 100 000 person-years. Those who had 6 or more amalgam restorations had a higher risk of future ADHD in the unadjusted Cox proportional hazard regression model (hazard ratio=1.20, 95% confidence interval [CI]=1.04-1.38, P=.015) than those who had received composite resin or glass ionomer restorations. However, after adjustment for potential confounding factors, the result was found to be confounded by age. Conclusions:The univariate analysis results showed that those who had 6 or more amalgam restorations had a 20% higher risk of future ADHD; however, the association disappeared after the model was adjusted for age. Despite this study analysing a larger sample than those analysed in previous studies, no association was observed between young patients' having received amalgam restorations and a future ADHD diagnosis. Further research aimed at evaluating the association between dental amalgam and other subsequent neuropsychological effects is warranted, especially for people who are vulnerable to mercury exposure. K E Y W O R D SADHD, amalgam, survival analysis, Taiwan national health insurance research database

A Comparison of Salivary Mercury Levels in Children with Attention Deficit/Hyperactivity Disorder When Compared to Age-matched Controls: A Case-control Observational Study

“…A recent study by Lin et al conducted in a sample of 80,000 mothers in the United States showed that although there was a weak positive association between the presence of amalgam restorations and ADHD, there was insufficient evidence to establish any meaningful relationship. 19 The results of our study seem to support this hypothesis and are in keeping with the studies of Karouna-Renier et al 9 and Van Wijngaarden et al 11 that suggest a low level of evidence between prenatal mercury level and ADHD.…”

“…Salivary analysis of mercury provides a relatively easy measure to compare mercury levels in children with ADHD and those without ADHD. [15][16][17][18] While few studies have successfully shown increased mercury levels in the blood, urine, and saliva of individuals with ADHD, 13,14,19 there has been no systematic attempt made to evaluate the age, demographic, or oral health factors that could influence the levels of mercury in the saliva of children with ADHD when compared to age-and gender-matched controls.…”

Can government‐supported preventive fluoride varnish application service reduce pulp‐involved primary molars?

“…No significant difference in age or sex was observed between the sampled group and all enrollees in the country's health insurance program. This database has been adopted in many longitudinal epidemiological and cost‐effectiveness studies .…”

Annual review of selected scientific literature: A report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry

“…One study used a nationwide database of more than 88 000 young people to investigate the association between amalgam restorations and attention-deficit/hyperactivity disorder (ADHD). 253 Children with one or more restorations and no ADHD history before 2001 were tracked through 2011 for a positive diagnosis of ADHD. In total, 2073 (2.4%) received a positive ADHD diagnosis yielding an incidence rate of 32.4 per 100 000 person-years, but there was no significant difference between those receiving amalgam and composite resin restorations.…”