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Dr. Gregory J Duffner, D.D.S.

General Practice Dentistry in Homewood, IL · enumerated 2010 · practices at Drs. Kreuz and Duffner, DDS, Ltd..

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

National Provider Identifier

1225340375

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Registry record

Entity type Individual (Type 1)
Name Dr. Gregory J Duffner
Credential D.D.S.
Sex Male
Practice address 18040 Park Ave, Homewood, IL, 60430
Phone (708) 792-2779
Fax (708) 798-6988
Enumeration date Jul 6, 2010
Last updated in NPPES Oct 23, 2025

Taxonomy & licenses

1223G0001X General Practice Dentistry Dental Providers · License 019-019782 (IL) 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

Where does Gregory Duffner practice?
The practice location on file with NPPES is in Homewood, IL. Providers can have multiple locations; NPPES lists the primary practice address.
What is the NPI number for Gregory Duffner?
The National Provider Identifier (NPI) for Gregory Duffner is 1225340375, a Type 1 (individual) record in the CMS NPPES registry.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2025-10-23.