Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum Sole proprietor

Dr. Marc Scott Fenster, D.M.D.

General Practice Dentistry in Smithtown, NY · enumerated 2010.

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

National Provider Identifier

1821317223

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Registry record

Entity type Individual (Type 1)

Name Dr. Marc Scott Fenster

Credential D.M.D.

Sex Male

Practice address Smithtown, NY, 11787

Phone (631) 724-6960

Fax (631) 724-6886

Enumeration date May 25, 2010

Last updated in NPPES May 25, 2010

Street address withheld: NPPES sole-proprietor addresses can be home addresses. See our data policy.

Taxonomy & licenses

1223G0001X General Practice Dentistry Dental Providers · License 047688 (NY) Primary

DMD · Doctor of Medicine in Dentistry: A licensed dentist; DMD and DDS are equivalent dental degrees. About the DMD 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.

Read the full guide → Validate an NPI →

Frequently asked questions

Is NPI 1821317223 active?

Yes, as of the latest NPPES snapshot, NPI 1821317223 is active (record last updated 2010-05-25).

How do I verify Marc Fenster's NPI record?

Cross-check NPI 1821317223 against the official CMS registry at npiregistry.cms.hhs.gov. This page mirrors the same public NPPES data with a monthly snapshot.

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2010-05-25.