Table 2 Classification of OTM type
From: Predictability of lower incisor tip using clear aligner therapy
Classification of OTM | Explanation | AP/IE ratio | Distance of CRot from CRes | |
|---|---|---|---|---|
| Root movement
| CRot close to incisal edge, displacement of IE is minimal | IF AP/IE < − 1.5 OR AP/IE > 2.4 AND “Ap movement” > 0.5 mm | 6 < CRot < 30 |
Uncontrolled tipping
| CRot close to CRes, displacement of IE and AP similar in magnitude but opposite in direction | IF − 1.5 < AP/IE < −0.2 AND “Ap movement” > 0.5 mm AND “IE movement” > 0.5 mm | −3 < CRot < 6 | |
Controlled tipping
| CRot close to apex, displacement of Ap is minimal | IF − 0.2 < AP/IE < 0.5 AND “IE movement” > 0.5 mm | 30 < CRot < −3 | |
Translation
| CRot approaching infinity, displacement of Ap and IE similar in magnitude and direction | IF 0.5 < AP/IE < 2.4 AND “Ap movement” > 0.5 mm AND “IE movement” > 0.5 mm | CRot > 30 OR CRot < −30 | |
Clinically insignificant movement (CIM) | A/IE fits within above category but Apex AND/OR IE movement < 0.5 mm |
