TABLE 2.

Oulu Resorption Score

Variable	Score
Extent (ie, remaining bone volume)
No BFR/remaining bone volume = 100%	0
Remaining bone volume 75% to 99.9%	0
Remaining bone volume 25% to 74.9%	2
Remaining bone volume <25%	3
Severity of perforations due to BFR
No BFR or only cancellous bone loss	0
Nonperforating resorption	1
A new bicortical perforation of <1.0 cm	2
A new bicortical perforation of ≥1.0 cm	3
Focus (ie, total integrity of the bone flap)
No BFR	0
One focal BFR change	0
Multiple BFR foci	2
Diffuse BFR: signs of BFR throughout the flap area	3

BFR = bone flap resorption.

Modified with permission from Korhonen et al⁶⁹ under the Creative Commons Attribution 4.0 International License.