William Chen, D.D.S.
NPI 1639375991 · Endodontics · Fullerton, CA
William Chen, D.D.S. is a Endodontics provider in Fullerton, CA (NPI 1639375991).
Provider details
- NPI number
- 1639375991
- Entity type
- Individual
- Primary specialty
- EndodonticsDental Providers
- Credential
- D.D.S.
- Sex
- Male
- Sole proprietor
- Yes
- License
- 45838 (CA)
Specialties & taxonomies
Dental Providers
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure33% of score
18 yrs in NPPES registry
- Profile completeness33% of score
100% of core fields populated
- Practice footprint20% of score
1 documented practice location
- Open Payments transparency13% of score
Has Open Payments disclosures (2024)
Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 3 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Amoxicillin | 40 | 37 |
| Methylprednisolone | 37 | 34 |
| Clindamycin Hcl | 11 | — |
Medicare Part D only. These counts cover prescriptions paid through Medicare Part D in 2024 — they do notinclude cash-pay, commercial-insurance, Medicaid, or Part B–administered drugs, and badly undercount high cash-pay categories (e.g. GLP-1 weight-loss, testosterone, and ED medications). Any drug with 10 or fewer claims is omitted by CMS, and beneficiary counts under 11 are suppressed — so a missing drug means no Part D record, never zero. This is a factual claims summary, not an endorsement, not medical advice, and not a consumer report. Source: CMS Medicare Part D Prescribers — by Provider and Drug.
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$214 across 7 records (Open Payments 2024)
Open Payments discloses payments and transfers of value (meals, travel, consulting, research, royalties) from drug and device makers to providers. This is a transparency signal, not a verdict — such payments are legal and common, and their presence is neither an endorsement nor a criticism. Source: CMS Open Payments, program year 2024.
Practice location
Mailing address
Registry dates
- Enumerated
- 2007-06-25
- Last updated
- 2007-07-08
Frequently asked questions
- What is William Chen's NPI number?
- William Chen's National Provider Identifier (NPI) is 1639375991, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is William Chen's specialty?
- William Chen is listed in the NPPES registry with a primary specialty of Endodontics (Dental Providers).
- Where is William Chen located?
- William Chen's practice location on file with NPPES is 259 Laguna Rd, Fullerton, CA 92835-2515.
- What is William Chen's phone number?
- The practice phone number listed in the NPPES registry for William Chen is (714) 738-6651.
- Is William Chen's NPI active?
- Yes — William Chen's NPI (1639375991) is active in the NPPES registry as of the last update on 2007-07-08.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.