Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Mr. William John Toonen, DDS

Dentist in Wauwatosa, WI · enumerated 2007 · practices at Tosa Dental LLC.

Data current as of Jul 13, 2026 · sourced from CMS NPPES

National Provider Identifier

1891915856

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Registry record

Entity type Individual (Type 1)

Name Mr. William John Toonen

Credential DDS

Sex Male

Practice address 8715 W North Ave, Wauwatosa, WI, 53226

Phone (414) 258-5660

Fax (414) 258-5336

Enumeration date May 1, 2007

Last updated in NPPES Jul 8, 2007

Taxonomy & licenses

122300000X Dentist Dental Providers · License 5000574 (WI) Primary

DDS · Doctor of Dental Surgery: A licensed dentist; DDS and DMD are equivalent dental degrees. About the DDS credential

What is an NPI number?

A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes, even if the provider moves or changes specialty.

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Frequently asked questions

How do I verify William Toonen's NPI record?

Cross-check NPI 1891915856 against the official CMS registry at npiregistry.cms.hhs.gov. This page mirrors the same public NPPES data with a monthly snapshot.

Is NPI 1891915856 active?

Yes, as of the latest NPPES snapshot, NPI 1891915856 is active (record last updated 2007-07-08).

Other providers at this practice address

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Tosa Dental LLC Dentist · Wauwatosa, WI NPI 1649643222 Stefanie Marvin Speech-Language Pathologist · Wauwatosa, WI NPI 1952033813 Jehan Salous Pathology Specialist/Technologist · Wauwatosa, WI NPI 1366277923

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2007-07-08.