Periapical Index
Also written as: PAI — Periapical Index
A five-point ordinal radiographic scoring system (PAI) used to classify the severity of periapical tissue changes visible on periapical radiographs.
Full Definition
The Periapical Index (PAI) is a validated radiographic scoring tool developed by Ørstavik et al. to standardize the assessment of periapical status on a scale from 1 (normal periapical structures) to 5 (severe periodontitis with exacerbating features). It is widely used in epidemiological studies and treatment outcome research as an outcome measure. Editors should ensure the abbreviation 'PAI' is defined on first use and that individual scores are reported as numerals (PAI score 3), not written out. Authors sometimes confuse the PAI with the Periapical Osteoitis Index (POI), a distinct scoring tool; editors should flag any discrepancy between the tool described and the one cited.
Usage
Usage note: Define 'PAI' on first use. Report individual scores as Arabic numerals (PAI 1–5). Verify the correct Ørstavik citation if referenced by authors.
In Context
- "Preoperative periapical radiographs were scored using the Periapical Index (PAI), with scores of 3 or above indicating pathology." — Outcome study, materials and methods
- "A reduction in PAI score from 4 to 1 was observed at the 12-month recall appointment." — Case report, follow-up section