Peer Assessment Rating
The Peer Assessment Rating ( Peer Assessment Rating Index , PAR index ) describes the severity of a malocclusion with a single number. The expression in German means something like "assessment by peer review" (see " Peer Assessment "). By comparing the PAR index at the beginning of treatment with the index at the end of treatment, the quality of orthodontic treatments can be determined. It is therefore sometimes referred to in the English literature as the "Index of Orthodontic Treatment Outcome".
Origin of the PAR index
The PAR index was developed in 1987 by a group of ten experienced orthodontists from the British Orthodontic Standards Working Party. After the index was checked from various points of view and, in particular, the weighting of the individual components that make up the index was determined in a complex process, it was published in 1992 by a group led by Stephen Richmond.
The PAR index consists of several components. In the original publications, 13 components were named, which were regrouped in later revisions and ultimately combined into 5 components.
In Austria , the use of the PAR index for assessing the quality of orthodontic treatment has been made mandatory by the social insurance funds since July 1, 2015 . To determine the need for treatment according to social security criteria, the application of the IOTN (Index of Orthodontic Treatment Need) was also prescribed.
Structure of the PAR index
The PAR index consists of five components:
- Upper and lower front tooth segment (front tooth component) - The following are assessed : contact point shifts , gaps, impacted teeth
- Buccal occlusion components - the following are assessed : sagittal teeth in the posterior region, transverse teeth in the posterior region, vertical teeth in the posterior region
- Sagittal overbite (overjet component) - The following are assessed: sagittal overbite , frontal crossbite
- Deep bite / open bite (vertical overbite component) - The following are assessed : frontal deep bite , frontal open bite
- Midline component - the following is assessed: midline shift between the upper and lower jaw
In each of these components, points are awarded for deviations from the norm occlusion . Only permanent teeth are assessed. A weighting factor is specified for each component . The points within a component are each multiplied by this factor. The points obtained in this way from the 5 components are finally added to the total number of points in the PAR index.
Determination of the number of points
Upper and lower front tooth segment (front tooth component)
The anterior segments of the upper and lower jaw from canine to canine are assessed with regard to the following criteria:
Contact point shifts
The contact point displacements of neighboring permanent teeth are measured. The greater the shift, the more points are awarded.
| PAR points in the anterior component | ||
|---|---|---|
| Extent of the contact point shift , measuring range: teeth 3 to 3 | Points | |
| 0mm - 1mm | 0 | |
| > 1mm - 2mm | 1 | |
| > 2mm - 4mm | 2 | |
| > 4mm - 8mm | 3 | |
| > 8mm | 4th | |
| Impacted tooth (displaced or gap ≤4mm) | 5 | |
Buccal occlusion component
The toothing in the posterior area is assessed in the sagittal relation (measuring range: teeth 3 to 8), in the vertical relation (measuring range: teeth 3 to 8) and in the transverse relation (measuring range: teeth 4 to 8).
Sagittal relation
An assessment is made as to whether, viewed from the buccal, the cusps and fossa are fully interlocked. Slight deviations are assessed with one PAR point, a cusp-cusp toothing is assessed with 2 PAR points. It is irrelevant whether there is a shift towards Angle Class II or III. The right and left sides are assessed separately.
Vertical relation
An open bite of more than 2mm on at least two antagonistic pairs of teeth in the measuring range of one side is rated with a PAR point. Deep bite in the measuring range remains unevaluated. The right and left sides are assessed separately.
Transversal relation
There are cross-bite, edge bite and scissors bite assessed. The more teeth are affected, the more PAR points are awarded. The right and left sides are assessed separately.
| PAR points in the buccal occlusion component | ||
|---|---|---|
| Extent of deviation | Points | |
| Sagittal relation (anterior-posterior) , measuring range: teeth 3 to 8 | ||
| Good intermeshing | 0 | |
| Less than half the premolar width deviation | 1 | |
| Half of the premolar width deviation (cusp-cusp toothing) | 2 | |
| Vertical relation (open bite) , measuring range: teeth 3 to 8 | ||
| Not an open bite | 0 | |
| Laterally open bite> 2mm with at least 2 pairs of teeth | 1 | |
| Transverse relation (cross bite, head bite, scissor bite) , measuring range: teeth 4 to 8 | ||
| No cross bite | 0 | |
| Cross bite tendency (head bite) | 1 | |
| Single tooth in a cross or scissor bite | 2 | |
| More than one tooth in the crossbite | 3 | |
| More than a scissor bite tooth | 4th | |
Sagittal overbite (overjet component)
The positive sagittal overbite (overjet, incisor step, measuring range: teeth 2 to 2) and the frontal crossbite (negative sagittal overbite, measuring range: teeth 3 to 3) are assessed.
Positive overjet
The distance from the most labial upper incisor to its antagonistic incisor in the lower jaw is measured, parallel to the occlusal plane and radially to the dental arch.
Frontal cross bite
The negative overjet corresponds to a frontal crossbite . Be judged incisors and canines . Depending on how many teeth are affected, more or fewer PAR points are awarded.
If points can be given for an enlarged positive overjet as well as for a frontal crossbite, they are added together.
| PAR points in the overjet component | |||
|---|---|---|---|
| Extent of positive overjet | Points | Extent of the anterior crossbite | Points |
| 0mm - 3mm | 0 | No cross bite | 0 |
| > 3mm - 5mm | 1 | One or more teeth in the square bite | 1 |
| > 5mm - 7mm | 2 | Single tooth in a cross bite | 2 |
| > 7mm - 9mm | 3 | Two teeth in a crossbite | 3 |
| > 9mm | 4th | More than two teeth in the cross bite | 4th |
| Measuring range: teeth 2 to 2 | Measuring range: teeth 3 to 3 | ||
Deep bite / open bite (vertical overbite component)
The extent of the deep bite and the open bite in the incisor area are assessed.
Deep bite
It measures how much an upper incisor covers a lower one. The greatest overlap counts. The stronger the deep bite , the more PAR points are awarded.
Open bite
The normal distance from the cutting edge of an upper incisor to the antagonistic lower incisor is measured. The largest measurable distance counts. The larger the open bite , the more PAR points are awarded.
If points can be awarded for both a deep bite and an open bite, these are added together.
| PAR points in the vertical overbite component | |||
|---|---|---|---|
| Extent of the deep bite , measuring range: teeth 2 to 2 | Points | Extent of the open bite , measuring range: teeth 2 to 2 | Points |
| Covered up to ⅓ of the lower incisor | 0 | Not an open bite | 0 |
| > ⅓ up to ⅔ of the lower incisor covered | 1 | Open bite ≤1mm | 1 |
| > ⅔ but does not cover the entire crown of the lower incisor | 2 | Open bite> 1mm to 2mm | 2 |
| Entire crown or more of the lower incisor covered | 3 | Open bite> 2mm to 4mm | 3 |
| Open bite> 4mm | 4th | ||
Centerline component
The deviation of the arch centers from the upper to the lower jaw is assessed by determining whether the upper center (contact of the upper central incisors) coincides with the lower center (contact of the lower central incisors), or how much the upper center overlaps one another projected lower incisor. Depending on how strong the deviation of the center lines is, more or fewer PAR points are awarded.
| PAR points in the center line component | |
|---|---|
| The amount of centerline shift | Points |
| Centers match or shift up to ¼ the width of a lower incisor | 0 |
| Displacement more than ¼ to ½ the width of a lower incisor | 1 |
| Displacement more than ½ the width of a lower incisor | 2 |
Weighting of the PAR points
The points awarded for the five components are not included in the PAR index with the same value. A weighting factor is given for each component, by which the points of the respective component are to be multiplied.
| Weighting factors | |
|---|---|
| component | weighting |
| Anterior component | 1 |
| Buccal occlusion component | 1 |
| Overjet component | 6th |
| Vertical overbite component | 2 |
| Centerline component | 4th |
The PAR index is calculated from the sum of the weighted PAR points of all five components.
Calculation of the quality of treatment
A given tooth position is described as "excellent" if there are fewer than 5 PAR points, as "acceptable" if there are 5 to 10 PAR points and "unacceptable" if there are more than 10 PAR points.
The improvement in a given situation can be determined by determining the reduction in the number of PAR points, which, however, can only lead to a meaningful statement in an initial situation with many PAR points. Therefore, the percentage improvement of the original PAR value is usually determined.
Calculation of the percentage improvement: x 100
From a reduction of the PAR points by 30%, one can speak of an improvement in the orthodontic situation, from a 70% reduction of a strong improvement. Good orthodontists should achieve or exceed an average PAR index improvement of 70% through their treatments.
Special features of the PAR index in Austria
Application in individual cases
The PAR index is intended to make the quality of orthodontic practices or treatment centers comparable, for which an improvement of at least 70% of the index between the start of treatment and the end of treatment is described as desirable. In contrast to this, in Austria an improvement of 70% of the points of the PAR index for each individual treatment case is required by the social insurance.
Commitment to digitization
In communication between orthodontists and social security, all documents must be transmitted digitally after a transition period planned until the end of 2021. To measure virtual tooth models, their digital measurement is therefore necessary. For the Austrian market, suitable modules of the OnyxCeph³ measurement program from Image Instruments GmbH, Niederwaldstraße 3, D-09123 Chemnitz, which meet the requirements for digital measurement of the PAR index and the Austrian version of the IOTN , were developed together with the Association of Austrian Orthodontists .
literature
- Gabriele Watzer, Armin Watzer: IOTN and PAR-Index in Austria - manual for correct and correct use . Published by the Association of Austrian Orthodontists, 2020. ISBN 978-3-9519790-0-7
- Stephen Richmond: Evaluating Effective Orthodontic Care . First Numerics Ltd., Cardiff, 2005, Reprint 2014. ISBN 0-9549670-1-1 .
Individual evidence
- ↑ Shaw, WC, Richmond, S and O'Brien, KD. The use of occlusal indices: A European perspective. American Journal of Orthodontics and Dentofacial Orthopedics. 1995, Vol. 107, pp. 1-10.
- ↑ Richmond, S, Shaw, WC, O'Brien, KD, Buchanan, IB, Jones, R, Stephens, CD, Roberts, CT and Andrews, M. The development of the PAR Index (Peer Assessment Rating): reliability and validity . European Journal of Orthodontics. April 1992, Vol. 14, 2, pp. 125-139.
- ↑ Richmond, S, Shaw, WC, Roberts, CT and Andrews, M. The PAR Index (Peer Assessment Rating): methods to determine outcome of orthodontic treatment in terms of improvement and standards. European Journal of Orthodontics. June 1992, Vol. 14, 3, pp. 180-187.
- ↑ Richmond, S, O'Brien, KD, Buchanan, IB and Burden, D. An Introduction to Occlusal Indices. Mandent Press. 1992, reprint 1994
- ^ Richmond, S. Evaluating Effective Orthodontic Care: First Numerics Ltd., Cardiff, 2005, Reprint 2014. ISBN 0-9549670-1-1 .
- ↑ General orthodontic contract for services according to § 153a ASVG (§ 94a GSVG, § 95a BSVG, § 69a B-KUVG) and the guideline tariff according to § 343c ASVG, concluded between the Austrian Chamber of Dentists and the main association of social insurance institutions . 2015.
- ↑ Official announcement of the Austrian social insurance (Hauptverband) No. 66/2015, 7th amendment to the model statute 2011. 2015.
- ↑ Watzer, G and Watzer, A: IOTN and PAR index in Austria - manual for the correct and proper application. Published by the Association of Austrian Orthodontists, 2020. ISBN 978-3-9519790-0-7
- ^ Richmond, S. Evaluating Effective Orthodontic Care: First Numerics Ltd., Cardiff, 2005, Reprint 2014. ISBN 0-9549670-1-1 .
- ↑ Richmond, S, Shaw, WC, Roberts, CT and Andrews, M. The PAR Index (Peer Assessment Rating): methods to determine outcome of orthodontic treatment in terms of improvement and standards. European Journal of Orthodontics. June 1992, Vol. 14, 3, pp. 180-187.
- ↑ Richmond, S, Shaw, WC, Roberts, CT and Andrews, M. The PAR Index (Peer Assessment Rating): methods to determine outcome of orthodontic treatment in terms of improvement and standards. European Journal of Orthodontics. June 1992, Vol. 14, 3, pp. 180-187.
- ^ Richmond, S. Evaluating Effective Orthodontic Care: First Numerics Ltd., Cardiff, 2005, Reprint 2014. ISBN 0-9549670-1-1 .
- ↑ Watzer, G and Watzer, A: IOTN and PAR index in Austria - manual for the correct and proper application. Published by the Association of Austrian Orthodontists, 2020. ISBN 978-3-9519790-0-7
- ↑ Richmond, S, Shaw, WC, Roberts, CT and Andrews, M. The PAR Index (Peer Assessment Rating): methods to determine outcome of orthodontic treatment in terms of improvement and standards. European Journal of Orthodontics. June 1992, Vol. 14, 3, pp. 180-187.
- ↑ Richmond, S, O'Brien, KD, Buchanan, IB and Burden, D. An Introduction to Occlusal Indices. Mandent Press. 1992, reprint 1994
- ^ Richmond, S. Evaluating Effective Orthodontic Care: First Numerics Ltd., Cardiff, 2005, Reprint 2014. ISBN 0-9549670-1-1 .
- ↑ Richmond, S, O'Brien, KD, Buchanan, IB and Burden, D. An Introduction to Occlusal Indices. Mandent Press. 1992, reprint 1994
- ^ Richmond, S. Evaluating Effective Orthodontic Care: First Numerics Ltd., Cardiff, 2005, Reprint 2014. ISBN 0-9549670-1-1 .
- ↑ Official announcement of the Austrian social security - Austrian Health Insurance No. 186. 2019.
- ↑ Official announcement of the Austrian Social Insurance - Insurance Company for Public Employees, Railways and Mining No. 18. 2020.
- ↑ Official announcement of the Austrian social insurance - Social Insurance Institution for the Self-Employed No. 153. 2019.
- ↑ Watzer, G and Watzer, A: IOTN and PAR index in Austria - manual for the correct and proper application. Published by the Association of Austrian Orthodontists, 2020. ISBN 978-3-9519790-0-7