Clinical trial NCT00066118: Health Effects of Silver-Mercury Dental Fillings
Official title: The Casa Pia Study of the Health Effects of Dental Amalgam in Children.
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: PHASE3
Conditions: Caries, Dental
Keywords: neurologic
nerve conduction
neurobehavioral
renal disease
Lead sponsor: University of Washington
Sponsor class: OTHER
Collaborators: name: National Institute of Dental and Craniofacial Research (NIDCR)
First posted: 2003-08-05
Enrollment: 507
Sex: ALL
Minimum age (years): 8
Maximum age (years): 12
Standard ages: CHILD
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: TREATMENT

Brief summary: The purpose of this study is to determine whether there are detectable health effects of low-level mercury exposure (from normal exposure to mercury-containing dental fillings) in the known target organs/systems affected by elemental mercury exposure.

Detailed description: The Casa Pia Study of the Health Effects of Dental Amalgam in Children is a randomized, prospective clinical trial with the overall goal of determining if there are detectable health effects due to exposure from mercury-containing dental amalgam fillings. Children, thought to be the population most susceptible to any possible health effects, were randomly assigned to one of two treatment groups (total n=507). Subjects were originally enrolled at ages between 8-10 years of age. To participate, subjects must have: Dental caries in at least one posterior tooth; no prior exposure to dental amalgam; a blood lead of \<15ug/L; a urinary mercury level of \<10ug/L; an IQ as measured by the CTONI of \>67; and no prior or existing serious medical or neurologic condition. One group received only dental filling materials other than those containing mercury (plastic and ceramic composites), while the other group received mercury amalgam fillings where appropriate (in large restorations in back teeth), but the alternative materials everywhere else. Both treatment regimens are standard-of-care throughout the world. Subjects receive ongoing dental care via the study clinics, and continue to receive dental fillings as needed based on group assignment. The target organs of mercury exposure are renal and neurological. Baseline and annual repeated measures are taken on all subjects for renal function, nerve conduction velocity and a large battery of neurobehavioral tests. Follow-up is planned for a period of 7 years

Eligibility criteria: * Age 8-10 years of age
* Dental caries in at least one posterior tooth.
* No prior exposure to dental amalgam
* Blood lead of \<15ug/L
* Urinary mercury level of \<10ug/L
* IQ as measured by the CTONI of \>67
* No prior or existing serious medical or neurologic condition

Primary outcomes:
measure: Memory
measure: Rey Auditory Verbal Learning,
measure: Finger Windows,
measure: Visual Learning
measure: Visual Motor Functions
measure: Drawing, MatchingP
measure: Pegboard sub-tests from the Wide Range Assessment of Visual Motor Abilities.
measure: Attention/Concentration
measure: Coding
measure: Symbol Search
measure: Digit Span
measure: Standard Reaction Time
measure: Stroop
measure: Trails A and B.
measure: Neurological: Nerve Conduction Velocity
Secondary outcomes:
Other outcomes:
Locations:
city: Seattle
country: United States
facility: University of Washington, School of Dentistry
state: Washington
Study officials:
affiliation: University of Washington
name: Timothy DeRouen
role: PRINCIPAL_INVESTIGATOR
affiliation: University of Washington
name: Michael Martin
role: STUDY_CHAIR
References:
citation: DeRouen TA, Martin MD, Leroux BG, Townes BD, Woods JS, Leitao J, Castro-Caldas A, Luis H, Bernardo M, Rosenbaum G, Martins IP. Neurobehavioral effects of dental amalgam in children: a randomized clinical trial. JAMA. 2006 Apr 19;295(15):1784-92. doi: 10.1001/jama.295.15.1784.
citation: Bernardo M, Luis H, Martin MD, Leroux BG, Rue T, Leitao J, DeRouen TA. Survival and reasons for failure of amalgam versus composite posterior restorations placed in a randomized clinical trial. J Am Dent Assoc. 2007 Jun;138(6):775-83. doi: 10.14219/jada.archive.2007.0265.
citation: Woods JS, Martin MD, Leroux BG, DeRouen TA, Leitao JG, Bernardo MF, Luis HS, Simmonds PL, Kushleika JV, Huang Y. The contribution of dental amalgam to urinary mercury excretion in children. Environ Health Perspect. 2007 Oct;115(10):1527-31. doi: 10.1289/ehp.10249.
citation: Lauterbach M, Martins IP, Castro-Caldas A, Bernardo M, Luis H, Amaral H, Leitao J, Martin MD, Townes B, Rosenbaum G, Woods JS, Derouen T. Neurological outcomes in children with and without amalgam-related mercury exposure: seven years of longitudinal observations in a randomized trial. J Am Dent Assoc. 2008 Feb;139(2):138-45. doi: 10.14219/jada.archive.2008.0128.
citation: Woods JS, Martin MD, Leroux BG, DeRouen TA, Bernardo MF, Luis HS, Leitao JG, Kushleika JV, Rue TC, Korpak AM. Biomarkers of kidney integrity in children and adolescents with dental amalgam mercury exposure: findings from the Casa Pia children's amalgam trial. Environ Res. 2008 Nov;108(3):393-9. doi: 10.1016/j.envres.2008.07.003. Epub 2008 Aug 21.
citation: Woods JS, Martin MD, Leroux BG, DeRouen TA, Bernardo MF, Luis HS, Leitao JG, Simmonds PL, Echeverria D, Rue TC. Urinary porphyrin excretion in children with mercury amalgam treatment: findings from the Casa Pia Children's Dental Amalgam Trial. J Toxicol Environ Health A. 2009;72(14):891-6. doi: 10.1080/15287390902959557.