The deciduous mandibular lateral incisor is wider than the deciduous mandibular central incisor and asymmetrical. The deciduous incisors have a common function which is cutting food. The morphology of the tooth is similar to its permanent successor which is permanent mandibular lateral incisor.
Development and Eruption of Deciduous Mandibular Lateral Incisor
The calcification of the deciduous mandibular lateral incisor begins around the age of 16th week in utero. The tooth emerges into the oral cavity by the age of 13 months and the root is completed by the age of 1.5 years. The deciduous mandibular lateral incisor is replaced by the permanent mandibular lateral incisor by the age of 7 to 8 years.
Labial Aspect
- The labial surface of the crown of the deciduous mandibular lateral incisor is smooth with no developmental depression or groove.
- The Crown is wider and longer than the deciduous mandibular central incisor. A similar pattern is observed in the permanent mandibular incisors.
- The incisal ridge of the deciduous mandibular lateral incisor has a slope towards the distal side.
- The distoincisal angle of the tooth is more rounded as compared to the mesioincisal angle.
- In the apical third the root has a slight curvature towards the distal side of the tooth.
- The root of this tooth is longer than the root of the deciduous mandibular central incisor.
Lingual Aspect
- The cingulum of the primary mandibular lateral incisor is more well developed as compared to the cingulum of the deciduous mandibular central incisor.
- The mesial and the distal marginal ridges are also more well developed as compared to the deciduous mandibular central incisor.
- Due to well-developed marginal ridges and cingulum, the lingual fossa is slightly deeper in comparison with the deciduous mandibular central incisor.
- The mesial and the distal aspect of the crown and the root are slightly visible because of the crown and the root convergence towards the lingual aspect.
Mesial Aspect
- Convexity at the cervical third of the crown on the buccal and lingual aspect is pronounced.
- The mesial surface of the root of the deciduous mandibular lateral incisor is flat and evenly tapered towards the apex of the root.
- The cervical line of the tooth has a curvature towards the incisal aspect of the crown.
Distal Aspect
- The cervical line on the distal aspect of the deciduous mandibular lateral incisor is less curved towards the incisal aspect.
- A longitudinal developmental groove or depression is present on the root surface.
Incisal Aspect
- The crown of the deciduous mandibular lateral incisor is not symmetrical as compared to the deciduous mandibular central incisor which is symmetrical.
- This asymmetry in shape is because of the curvature of the incisal ridge and position of the cingulum which is offset more towards the distal side.
- The labial surface of the crown is more convex as compared to the deciduous mandibular central incisor.
- The center of the lingual surface of the crown is more concave because of well-developed marginal ridges and cingulum.