 Welcome back to another session on dentistry and more. So today's topic is incisor liability. So incisor liability there is nothing but the space difference between the permanent and primary incisors. So as we all know the size of permanent teeth is greater than the primary teeth. So once the primary teeth is exfoliated the permanent teeth erupts into the space of primary teeth. But it requires more space. As you can see here this red teeth are permanent teeth which is erupting and the black are deciduous teeth. So you can see the difference. The mesiodisthyl at least on a two dimension you can see the difference between the space available and space required. So this is a dotted red line is a space required and this black line is space available. So this difference is known as incisor liability. The space available and space required or space needed the difference between these two is known as incisor liability and which is 7mm in maxilla and 6mm in mantable. So how do we achieve this that incisor liability is achieved by the four mechanisms that is the more space will be achieved to accommodate the permanent incisors. So the first one is interdental spacing of primary incisors. So you know the primary incisors there is slight interdental spacing present. So when this permanent teeth erupts which are bigger incisor can utilize the space to get accommodate into that position. So that interdental spacing can be utilized that is the first option. The second mechanism is intercaline arch width growth. So as the new tooth erupts that is permanent incisors erupts there will be a width of arch in the canine to canine region. So it happens when this anterior erupts. So since it is bigger to get accommodated the arch itself expands from canine to canine region. So that also is a mechanism which the permanent incisors used to occupy its final position in the arch. So that is the second mechanism. The third mechanism is labial positioning of permanent incisors. So we know that the permanent teeth are more labial position or more forwardly placed compared to the primary dentition. Primary dentition is almost like upright position but the permanent teeth are more labially placed. So when it goes to the forward or labial position there is increase in arch size. So that also can be used to overcome the incisor liability that is labial positioning of permanent incisors. The last mechanism is favorable size ratio between primary and permanent incisors. Favorable size ratio is nothing but if we have a bigger or comparatively bigger primary tooth that we can say that it is a favorable ratio and if the size of deciduous anterior primary anterior is comparatively low that will be a unfavorable size ratio compared to the permanent teeth. So that is incisor liability it is the difference between space available and space needed for the anterior teeth. So when the bigger anterior permanent anterior that is incisor syrups we need more space that is known as incisor liability 7mm in maxilla 6mm in mandible. So this can be maxilla mandible. So this can be overcome by the interdental spacing of primary incisors, the intercanine arch width growth, labial positioning of permanent incisors, favorable size ratio. So all these can be utilized and overcome the incisor liability. So I will come up with a new session on dentistry and more. Thank you.