2006 ICD-9-CM Volume 1 Diagnosis Codes Home > Diseases Of The Digestive System 520-579 > Diseases Of Oral Cavity, Salivary Glands, And Jaws 520-529 > Gingival And Periodontal Diseases 523.* > 2006 ICD-9-CM Diagnosis 523.4 Chronic periodontitis View the most recent version of ICD-9-CM 523.4 Inflammatory reaction of the tissues surrounding a tooth (periodontium), usually resulting from the extension of gingival inflammation (gingivitis) into the periodontium. 523.4 is a specific code that can be used to specify a diagnosis 523.4 contains 15 index entries View the ICD-9-CM Volume 1 523.* hierarchy Alternate Terminology Alveolar pyorrhea Chronic pericoronitis Pericementitis (chronic) Periodontitis: NOS complex simplex 523.4 Excludes chronic apical periodontitis (522.6)