DR. JOHN MARK LEIB D.M.D.
NPI 1376604678
Dentist in O Fallon, IL

Q: What is John Leib's NPI number?

The NPI number for John Leib is 1376604678. It was assigned to this individual provider in the NPPES registry on December 12, 2006.

Q: What is John Leib's specialty?

The primary specialty registered for this NPI is Dentist with taxonomy code 122300000X.

Q: When was this NPI record last updated?

The NPPES record for John Leib was last updated on September 11, 2025. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 12 months ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.

Active since December 12, 2006

741 W STATE ST, SUITE 3, O FALLON, IL 62269(618) 628-1800(618) 628-3406 Get Directions Write a Review

NPPES record last updated: September 11, 2025. Verified against the NPPES registry weekly; last sync: October 04, 2026.

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About Dr. John Mark Leib D.m.d. NPPES

Official registry information on file with the National Plan and Provider Enumeration System.

DR. JOHN MARK LEIB D.M.D. (NPI 1376604678) is an individual dentist in O Fallon, Illinois and active in the NPI registry since December 2006.

NPPES Registry Identity

NPI1376604678

Entity TypeIndividualMale

Primary Taxonomy122300000X

Provider Legal NameDR. JOHN MARK LEIBCredential: D.M.D.

Location Address741 W STATE ST, SUITE 3O Fallon, IL 62269-1971

Mailing Address741 W State St, Suite 3O Fallon, IL 62269-1971 · (618) 628-1800 · Fax (618) 628-3406

Phone(618) 628-1800

Fax(618) 628-3406

Sole ProprietorNo

Enumeration DateDecember 12, 2006

Last NPPES UpdateSeptember 11, 2025

✔ NPI 1376604678 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses 2

★ Primary SpecialtyDentistDental Providers

Taxonomy Code122300000X

Definition

A dentist is a person qualified by a doctorate in dental surgery (D.D.S.) or dental medicine (D.M.D.), licensed by the state to practice dentistry, and practicing within the scope of that license. There is no difference between the two degrees: dentists who have a DMD or DDS have the same education. Universities have the prerogative to determine what degree is awarded. Both degrees use the same curriculum requirements set by the American Dental Association's Commission on Dental Accreditation. Generally, three or more years of undergraduate education plus four years of dental school is required to graduate and become a general dentist. State licensing boards accept either degree as equivalent, and both degrees allow licensed individuals to practice the same scope of general dentistry. Additional post-graduate training is required to become a dental specialist.

Also ListedDentist · Oral and Maxillofacial SurgeryTaxonomy 1223S0112X

741 W STATE ST, O Fallon, IL 62269

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Other Providers at the Same Location NPPES 10

Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.

DR. BRITTANY GILBRETH D.M.D

Dentist

741 W STATE ST, SUITE 1
O FALLON, IL 62269

St. Clair County (618) 632-2282

DR. KARA LYNN SCHREDER D.M.D.

Dentist (General Practice)

741 W STATE ST, SUITE 1
O FALLON, IL 62269

St. Clair County (618) 632-2282

KIRK DOUGLAS SATROM D.D.S., M.S.

Dentist (Orthodontics and Dentofacial Orthopedics)

741 W STATE ST, SUITE 2
O FALLON, IL 62269

St. Clair County (618) 624-0800

BOWMAN DENTAL GROUP

Dentist (General Practice)

741 W STATE ST, STE. 1
O FALLON, IL 62269

St. Clair County (618) 632-2282

ORAL SURGEONS OF SOUTHERN ILLINOIS

Dentist (Oral and Maxillofacial Surgery)

741 W STATE ST, SUITE 3
O FALLON, IL 62269

St. Clair County (618) 628-1800

DR. AVA LAUREN HOOD-OLSON D.M.D.

Dentist (Orthodontics and Dentofacial Orthopedics)

741 W STATE ST, SUITE 2
O FALLON, IL 62269

St. Clair County (618) 624-0800

DR. DALE ALLEN SCHUTTE D.D.S

Dentist

741 W STATE ST, SUITE 3
O FALLON, IL 62269

St. Clair County (618) 628-1800

TONYA L. BOWMAN D.M.D.

Dentist (General Practice)

741 W STATE ST
O FALLON, IL 62269

St. Clair County (618) 632-2282

Frequently Asked Questions NPPES & CMS

Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.

What is John Leib's NPI number?

The NPI number for John Leib is 1376604678. It was assigned to this individual provider in the NPPES registry on December 12, 2006.

Where is John Leib located?

John Leib practices at 741 W State St Suite 3, O Fallon, IL 62269. The listed phone number is (618) 628-1800.

What is John Leib's specialty?

The primary specialty registered for this NPI is Dentist with taxonomy code 122300000X.

When was this NPI record last updated?

The NPPES record for John Leib was last updated on September 11, 2025. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 12 months ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.