The document discusses the Peer Assessment Rating (PAR) index, which is used to evaluate orthodontic treatment outcomes. It was developed through meetings of experienced orthodontists who formulated the index using over 200 pre- and post-treatment cases. The PAR assigns scores to various components like anterior teeth alignment, overjet, overbite, and midline to provide a cumulative score. Treatment results are graded as greatly improved, improved, or no different based on the reduction in PAR scores from pre- to post-treatment. The document then provides detailed descriptions and scoring criteria for each component of the PAR index.

1. Nasir Al-Hamlan BDS, MPH, MSc, FDS RCSEd, FDS RCSEd, MOrth RCSEd, FICD
Consultant and Assistant Professor, Orthodontics
King Saud bin Abdulaziz University for Health Sciences
Riyadh, Saudi Arabia
@nhalhamlan
@saudibraces
nasiralhamlan
@nasiralhamlan
Peer Assessment Rating (PAR)
(Richmond et.al., 1992)

2. Peer Assessment Rating (PAR) (Richmond et.al., 1992)

3. Peer Assessment Rating (PAR) (Richmond et.al., 1992)
• Over 6 meetings with 10 experienced orthodontists to formulate
PAR index by using over 200 SM (pre-/post-treatment),
• Zero = good alignment and higher scores (rarely above 50)
indicate increasing degrees of irregularity,
• Grade treatment results for self teaching device, however; it can be
insensitive and misjudge individual patient needs, therefore it is
not an index of treatment need.

4. COMPONENTS AND WEIGHTINGS
COMPONENTS WEIGHTINGS
Upper/lower anterior segment x 1
Left/right buccal occlusion x 1
Overjet x 6
Overbite x 2
Centerline x 4
• Greatly improve: > 22 points
• Improved: > 30%
• Worse/no different: < 30%

5. Ruler

6. Advantages
• Accumulative scores,
• Gives grading treatment results,
• Reliable (Richmond et al., 1992),
• 2 minutes stated as time required for scoring.

7. Limitation (Hamdan and Rock, 1999)
• Sensitive with increased OJ
• OB low weighting
• Zero weighting for displacement

8. DESCRIPTION

9. • Anterior segments
- ULS/LLS
- Recording zone = canine (mesial contact points)
- Recorded features: Crowding, Spacing, Impaction
- Contact point displacement:
SCORE DISPLACEMENT
0 0 mm – 1 mm
1 1.1 mm – 2 mm
2 2.1 mm – 4 mm
3 4.1 mm – 8 mm
4 > 8 mm
5 Impacted teeth

10. • Anterior segments
- Impactions of canines and incisors are recorded
- Impacted = space between two adjacent teeth is ≤ 4 mm
- Ectopic incisors and canines are recorded in the anterior segment
- Contact point displacement scores and impacted/ectopic teeth
scores are summed ! overall score for anterior segment

11. • Buccal occlusion
- Record left and right and in all three planes
- Recording zone = canine "! LAST molar (either 1st, 2nd or 3rd)
- All features recorded with teeth in occlusion
- A-P, VERTICAL and TRANSVERSE scores are summed for each buccal segment

12. • Buccal occlusion
Score A-P
0 good interdigitation
1 < ½ unit from full
2 ½ unit (cusp-cusp)

13. • Buccal occlusion
Score VERTICAL
0 no open bite
1 lateral open bite > 2 mm on at least two teeth

14. • Buccal occlusion
Score TRANSVERSE
0 no crossbite
1 crossbite tendency
2 single tooth in crossbite
3 > 1 tooth in crossbite
4 > 1 tooth in scissors bite
• Do NOT sum x-bites and x-bite tendency

15. • Overjet
- Record OJ and anterior crossbites,
- Recording zone most prominent incisal edge,
- Some patients have OJ and anterior x-bite..record both and summate score:
Score OJ Score Anterior crossbite
0 0-3 mm 0 No crossbite
1 3.1 – 5 mm 1 One or more teeth edge-edge
2 5.1 – 7 mm 2 One single tooth in x-bite
3 7.1 – 9 mm 3 Two teeth in x-bite
4 > 9 mm 4 > Two teeth in x-bite
NOTE: Canine crossbites recorded in OJ assessment

16. • Overbite
- Record worst vertical overlap OR openbite of ANY of the four incisors (DO
NOT summate)
OPEN BITE OVERBITE
Score Score
0 No open bite 0 ≤ 1/3rd Lower Incisor
1 ≤ 1 mm 1 > 1/3rd < 2/3rd Lower Incisor
2 1.1 mm – 2 mm 2 > 2/3rd Lower Incisor
3 2.1 mm – 3 mm 3 ≥ full tooth coverage
4 ≥ 4 mm

17. • Centerline
- Difference between upper and lower midlines recorded in RELATION TO
LOWER DENTAL MIDLINE and NOT face.
Score Centerline
0 Coincident and up to ¼ lower incisor width
1 ¼ - ½ lower incisor width
2 > ½ lower incisor width

18. PAR- case analysis
• PRETREATMENT
ULS: (3-2) 1, (2-1) 0, (1-1) 0, (1-2) 1, (2-3) 2
Total = 4
Weighting 4 x 1 = 4
LLS: (3-2) 1, (2-1) 0, (1-1) 0, (1-2) 0, (2-3) 0
Total = 1
Weighting 1 x 1 = 1

19. • PRETREATMENT
• RBO: A-P = 0, Vertical = 0, Transverse = 0
Total = 0
Weighting 0 x 1 = 0
• LBO: A-P = 1, Vertical = 0, Transverse = 0
Total = 0
Weighting 1 x 1 = 1
PAR- case analysis

20. PRETREATMENT
• OJ: 10mm = 3, Crossbite = 0
Total = 3
Weighting 3 x 6 = 18
PAR- case analysis

21. PRETREATMENT
Either overbite or openbite
Overbite > 2/3rd of Lower Incisor =2
Total = 2
Weighting 2 x 2 = 4
CL: 1/2 Lower Incisor width = 1
Total = 1
Weighting 1 x 4 = 4
Total Pretreatment Score = 32 points
PAR- case analysis

22. POSTTREATMENT
ULS: (3-2) 0, (2-1) 0, (1-1) 0, (1-2) 0, (2-3) 0
Total = 0
Weighting 0 x 1 = 0
LLS: (3-2) 0, (2-1) 0, (1-1) 0, (1-2) 0, (2-3) 0
Total = 0
Weighting 0 x 1 = 0
PAR- case analysis

23. POSTTREATMENT
RBO: A-P = 1, Vertical = 0, Transverse = 0
Total = 1
Weighting 1 x 1 = 1
LBO: A-P = 0, Vertical = 0, Transverse = 0
Total = 0
Weighting 0 x 1 = 0
PAR- case analysis

24. POSTTREATMENT
OJ: 2mm = 0, Crossbite = 0
Total = 0
Weighting 0 x 6 = 0
Either overbite or openbite = 0
Total = 0
Weighting 0 x 2 = 0
CL: Coincident = 0
Total = 0
Weighting 0 x 4 = 0
Total Posttreatment Score = 1 point
PAR- case analysis

25. Measurement the Treatment Outcome
Points:
Pretreatment score (32) – Posttreatment score (1) = 31
> 22 (Greatly Improved)
Percentage:
Pretreatment score reduced was from 32 to 1 in posttreatment;
therefore, the reduction was 31 points.
32-------------------31
100-----------------96.88
96.88 > 30% (Improved)
PAR- case analysis

26. •Thank YOU