Incisor Liability
Write short note on incisor liability.
Answer.
Answer.
Incisor Liability
- Incisor liability was explained by Warren Mayne in 1969.
- The permanent incisors are larger than their primary incisors and thus require more space for their alignment “The difference between space available and space require is called incisor liability”.
- Favorable incisor liability occurs when primary dentition is an open dentition while unfavorable incisor liability occurs in closed dentition.
- Value of incisal liability in maxillary arch is 7 mm while it is 5 mm in mandibular arch.
- Various factors are responsible for the alignment of incisors, i.e.
- Interdental space: In primary dentition the space is present which help in alignment of incisors. Primate space is also used.
- Intercanine width: At the time of eruption of permanent incisor there is increase in the intercanine arch width which is 3–4 mm.
- Labial eruption of incisors: Primary incisors remain in uprighting position while the permanent incisors which replace them remain in labially proclined position. This causes the erupting permanent incisors to place them in a wider arch.
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