Pell and Gregory Classification
A radiographic classification system that grades the position and depth of impacted mandibular third molars in relation to the ramus and the second molar.
Full Definition
The Pell and Gregory classification uses two scales to describe lower wisdom tooth impaction: a positional class (I, II, or III) based on the space between the second molar and the anterior border of the ramus, and a depth grade (A, B, or C) based on the tooth's level relative to the occlusal plane of the adjacent molar. Together, these designations guide surgical planning and appear routinely in oral surgery referral letters, operative notes, and research papers. Editors must ensure that the Roman numerals for class and the uppercase letters for depth are used consistently and correctly. The term is an eponym and must be capitalised throughout; 'pell and gregory' in lowercase is an editorial error.
Usage
Usage note: Always capitalise as an eponym. Use Roman numerals (I, II, III) for class and uppercase letters (A, B, C) for depth. Write 'Pell and Gregory classification', not 'Pell & Gregory'.
In Context
- "The referral letter described the wisdom tooth as a Pell and Gregory Class II, Position B impaction requiring surgical removal." — Surgical referral letter
- "Standardise the classification nomenclature — the manuscript alternates between 'Class 2' and 'Class II', which are inconsistent with Pell and Gregory convention." — Copy-editing note