Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum
Dr. Gregory Holman Duncan, DDS
Dentist in Greenville, TX · enumerated 2006.
Data current as of Jul 13, 2026 · sourced from CMS NPPES
National Provider Identifier
1033228101
See something wrong? Report a correction
Registry record
Entity type Individual (Type 1)
Name Dr. Gregory Holman Duncan
Credential DDS
Sex Male
Practice address 4613 Stonewall Street, Suite A, Greenville, TX, 75401
Phone (903) 455-6075
Fax (903) 455-7589
Enumeration date Aug 30, 2006
Last updated in NPPES Jan 20, 2012
Taxonomy & licenses
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.
Frequently asked questions
Is this the official NPI registry?
No. NPI Portal is a private site built on public CMS NPPES data. The official registry is npiregistry.cms.hhs.gov, operated by CMS.
What specialty is Gregory Duncan?
Gregory Duncan is registered in NPPES with the primary taxonomy of Dentist. The taxonomy code describes the provider's classification and area of specialization for claims and credentialing.
Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2012-01-20.