Description

Braly and Maxwell used the Predisposition Index as a semiquantitative method for identifying the risk of a tooth becoming fractured. This can help the dentist identify teeth that are at risk for fracture so that preventive steps can be taken. The authors are from the University of California in San Francisco.


Risk Factor

Finding

Points

excessive contact of posterior cusps during eccentric jaw movements

absent

0

 

present

1

large, internally retained restorations

absent

0

 

present

1

attrition, abrasion, and/or erosion

absent

0

 

present

1

steep cusp/deep groove occlusal morphology

absent

0

 

present

1

patient history of "breaking" teeth and/or restorations

absent

0

 

present

1

mandibular second molar, mandibular first molar, or maxillary premolar

no

0

 

yes

1

 

where:

• Eccentric jaw movements include open anterior occlusions, anterior (cuspid) wear, crossbite, and/or edge-to-edge occlusions.

 

predisposition index for a tooth =

= SUM(points for all 6 risk factors)

 

Interpretation:

• minimum index: 0

• maximum index: 6

• The higher the index, the greater risk for dental fracture.

• A tooth with a high score should be considered for a protective restoration, especially if the patient is > 40 years of age.

 

Limitation:

• This will not identify all patients who will develop a dental fracture, since it does not include such things as biting on a hard object. However, that is a random event.


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