Holtta et al developed the Defect Index (DeI) for reporting abnormal root development of permanent teeth. This can be used to summarize total damage to tooth development seen in children treated for cancer. The authors are from the University of Helsinki in Finland.
Method: panoramic dental X-rays were examined
Teeth are not counted if:
(1) not reliably seen on the X-ray
(2) tooth still developing and final outcome unclear
(3) missing tooth for causes other than aplasia
Parameters:
(1) root to crown ratio (R/C), see above
(2) gross tooth defect
|
R/C Ratio |
Disturbance in Root Development |
|
> 1.6 |
none |
|
1.2 to 1.6 |
mild |
|
0.9 to 1.1 |
severe |
|
< 0.9 |
very severe |
|
R/C Ratio |
Gross Tooth Defect |
Grade |
|
> 1.6 |
NA |
D0 |
|
1.2 to 1.6 |
NA |
D1 |
|
0.9 to 1.1 |
NA |
D2 |
|
< 0.9 |
arrested root development |
D3 |
|
NA |
microdontia (very small tooth) |
D4 |
|
NA |
aplasia (missing tooth) |
D5 |
where:
• Microdontia involves the crown size being <= half of the expected size.
It is important that aplasia not be diagnosed at an age when the permanent tooth has not yet appeared.
|
Tooth |
Age at Which Aplasia Can Be Diagnosed |
|
first premolar |
>= 5 years |
|
second premolar |
>= 6 years |
|
second molar |
>= 6 years |
|
third molar |
>= 13 years |
defect index =
= ((number of teeth at D0) * 0) + ((number of teeth at D1) * 1) + ((number of teeth at D2) * 2) + ((number of teeth at D3) * 3) + ((number of teeth at D4) * 4) + ((number of teeth at D5) * 5)
total number of assessed teeth =
= (number of teeth at D0) + (number of teeth at D1) + (number of teeth at D2) + (number of teeth at D3) + (number of teeth at D4) + (number of teeth at D5)
Interpretation:
• minimum score: 0
• maximum score: 160
• A person with normal permanent teeth has defect index of 0.
• The higher the index the worse the permanent dentition.
Specialty: Otolaryngology
