The Peer Assessment Rating (PAR) index is a standardized method for quantitating abnormal occlusion. It can be used both for the initial assessment and to evaluate the amount of change after an intervention. The score was developed at the University of Bristol and Bristol Dental Hospital.
Components of the PAR index:
(1) upper right segment
(2) upper anterior segment
(3) upper left segment
(4) lower right segment
(5) lower anterior segment
(6) lower left segment
(7) right buccal occlusion
(8) left buccal occlusion
(9) overjet
(10) overbite
(11) centerline
left and right segments: 3 spaces (3-4, 4-5, 5-6)
(1) first premolar (tooth 4)
(2) second premolar (tooth 5)
(3) first molar (tooth 6)
anterior segment: 5 spaces (3-2, 2-1, 1-1, 1-2, 2-3)
(1) left first incisor (tooth 1)
(2) left second incisor (tooth 2)
(3) left canine (tooth 3)
(4) right first incisor (tooth 1)
(5) right second incisor (tooth 2)
(6) left canine (tooth 3)
The various conventions for the score are given in Appendix 1 (pages138-139, Richmond, 1992).
score for each buccal segment =
= (points for displacements for all 3 spaces) + (points for impaction for all 3 teeth)
score for each anterior segment =
= (points for displacements for all 5 spaces) + (points for impaction for all 6 teeth)
buccal occlusion subscore =
= (points for antero-posterior irregularities) + (points for vertical irregularities) + (points for transverse irregularities)
overjet score =
= (points for overjet of most severely affected tooth) + (points for cross-bite)
overbite score =
= (points for open bite) + (points for the tooth with the greatest overlap)
PAR index =
= SUM(points for all 11 components)
Interpretation:
• minimum score: 0
• maximum score: rarely over 50
• A score of 0 indicates good alignment.
The score may be weighted by multiplying a factor times each component score:
|
Component |
Numbered Groups |
Weighting Factor |
|
buccal segments |
1, 3, 4, 6 |
0 |
|
upper anterior |
2 |
1 |
|
lower anterior |
5 |
1 |
|
buccal occlusion |
7 and 8 |
1 |
|
overjet |
9 |
6 |
|
overbite |
10 |
2 |
|
centerline |
11 |
4 |
weighted PAR index =
= SUM((weighting factor) * (unweighted points for component))
Performance:
• There was excellent reliability within and between examiners (interclass correlation coefficient > 0.91).
Specialty: Otolaryngology
ICD-10: ,
