521 Diseases of hard tissues of teeth (521.00-521.9) ICD-9-CM
The 521.00-521.9 block classified 521 diseases of hard tissues of teeth with 38 legacy diagnosis codes. None remain valid for claim submission; each code below links to its reference page with the official ICD-10-CM replacement under the CMS General Equivalence Mappings.
Retired Code Set
ICD-9-CM stopped being valid for U.S. claims with dates of service on or after October 1, 2015, when ICD-10-CM replaced it. Use this index for historical lookups and crosswalking; for current coding, start from the ICD-10-CM codes list or the ICD-9 / ICD-10 converter.
Legacy Codes in the 521.00-521.9 Block 38 codes
None of these codes remain valid for claim submission. Each code page shows its ICD-10-CM replacement under the CMS General Equivalence Mappings.
- 521.00 Dental caries NOS
- 521.01 Dental caries - enamel
- 521.02 Dental caries - dentine
- 521.03 Dental caries - pulp
- 521.04 Dental caries - arrested
- 521.05 Odontoclasia
- 521.06 Dentl caries-pit/fissure
- 521.07 Dentl caries-smooth surf
- 521.08 Dental caries-root surf
- 521.09 Dental caries NEC
- 521.10 Excessive attrition NOS
- 521.11 Excess attrition-enamel
- 521.12 Excess attrition-dentine
- 521.13 Excessive attrition-pulp
- 521.14 Excess attrition-local
- 521.15 Excess attrition-general
- 521.20 Abrasion NOS
- 521.21 Abrasion-enamel
- 521.22 Abrasion-dentine
- 521.23 Abrasion-pulp
- 521.24 Abrasion-localized
- 521.25 Abrasion-generalized
- 521.30 Erosion NOS
- 521.31 Erosion-enamel
- 521.32 Erosion-dentine
- 521.33 Erosion-pulp
- 521.34 Erosion-localized
- 521.35 Erosion-generalized
- 521.40 Path resorption NOS
- 521.41 Path resorption-internal
- 521.42 Path resorption-external
- 521.49 Path resorption NEC
- 521.5 Hypercementosis
- 521.6 Ankylosis of teeth
- 521.7 Intrin posteruptv color
- 521.81 Cracked tooth
- 521.89 Dis hard tiss teeth NEC
- 521.9 Hard tiss dis teeth NOS
Questions About This Page
Are the 521.00-521.9 codes still billable?
No. Every code in this block became invalid for U.S. claims after September 30, 2015. Each code page linked above shows the ICD-10-CM replacement CMS assigned in the General Equivalence Mappings, and the ICD-9 / ICD-10 converter translates any of them directly.
What did the 521.00-521.9 block classify?
The block classified 521 diseases of hard tissues of teeth with 38 codes in the final ICD-9-CM release. It sat under Diseases of the digestive system (520–579) in the legacy hierarchy.
Related References
Source: final CMS ICD-9-CM release (version date October 1, 2014). Retired from U.S. claims after September 30, 2015.
