William Michael Brennan, DDS
Dentist · Downers Grove, IL
William Michael Brennan, DDS is a dentist with a practice address in Downers Grove, Illinois, and NPI 1235142746, issued on Aug 14, 2006. Check the license (Illinois 19A15602, as entered in NPPES) with the Illinois board that licenses this profession; the Medicare figures below come from public CMS files.
- Name
- William Michael Brennan
- Credential
- DDS
- Primary taxonomy
- Dentist 122300000X
- License number
- 19A15602 IL
Self-reported in NPPES; status is on the state search - Practice location
- 5133 Washington St, Downers Grove, IL 60515
- Phone
- (630) 969-4645
- Enumerated
- Aug 14, 2006
- Record last updated
- Jul 8, 2007 (not updated in 19 years: call before relying on the address or phone)
- Entity
- Type 1 · individual
8 nearest dentist records → All 4,522 in Illinois → Look up another NPI →
Also registered at 5133 Washington St
A shared address usually means a shared clinic or building; it does not show who employs whom.
- William Brennan, D.D.S.Dentist1265501175
- Sarah Cline, L.C.S.W.Clinical Social Worker1588946669
- John Keenan, DDSDentist1124233218
- John Marchese, D.D.SDentist1073875357
- Rachel Powers, MA, LCPC, NCCProfessional Counselor1639313794
Verify William Michael Brennan in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersWhich Illinois board licenses this profession
Search for license 19A15602Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
80% fewer Medicare Part D claims than the average dentist in 2024
17 Medicare Part D claims, against an average of 86 among the 51,021 providers of this specialty who prescribed in Part D.
Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.
William Michael Brennan among 4,522 dentist records in Illinois
William Michael Brennan, DDS is one of 4,522 dentist records with a practice address in Illinois. 64% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2006, is newer than 2% of them.
- NPI issued2006 · 2% of these records are older, 81% newer
- In a Medicare fileYes · 64% of these records are
- In the CMS Doctors and Clinicians fileNo · under 1% of these records are
- Record last updated2007 · 74% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 122300000X and a Illinois practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
56 dentist records list a practice address in Downers Grove
They are 56 of the 1,899 NPPES records with a practice address in Downers Grove, and 4,522 dentist records in Illinois.
All 4,522 in Illinois → Every provider in Downers Grove → Dentist nationwide →
The 8 dentist records with the nearest ZIP codes
- Sara Banuelos, D.D.SDowners Grove, IL 605151164542429
- Keith Bram, D.D.S.Downers Grove, IL 605151609088418
- William Brennan, D.D.S.Downers Grove, IL 605151265501175
- John Keenan, DDSDowners Grove, IL 605151124233218
- Theresa Lao, D.D.S.Downers Grove, IL 605151275684367
- John Maffeo, DDSDowners Grove, IL 605151598834475
- Richard Patelski, DDS MAGDDowners Grove, IL 605151417166968
- Thomas Sarna, DDSDowners Grove, IL 605151760698765
Common questions
What is William Michael Brennan, DDS's NPI number?
William Michael Brennan, DDS's National Provider Identifier (NPI) is 1235142746, issued on Aug 14, 2006. An NPI identifies a provider in billing; it is not a license.
Where is William Michael Brennan, DDS located?
The NPPES record lists a practice address at 5133 Washington St, Downers Grove, IL, 60515. Phone: (630) 969-4645. Providers update this record themselves, so call before visiting.
How can I verify William Michael Brennan, DDS's license?
NPPES lists Illinois license number 19A15602, as entered by the provider. Search the Illinois board that licenses this profession; the NPPES record confirms identity only.
How much does William Michael Brennan, DDS prescribe under Medicare Part D?
In 2024, William Michael Brennan, DDS had 17 Medicare Part D claims; the average among dentist prescribers was 86. Part D covers Medicare prescriptions only.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.