Saturday, December 28, 2019

Child has unilateral posterior crossbite during eruption of lateral incisor due.. abnormal swallowing habit



Child has unilateral posterior crossbite during eruption of lateral incisor due to:
A- abnormal chewing habit
b- abnormal swallowing habit ***
C- congenital.

The higher lateral incisor is the second tooth the dental arch. It is similar to mandibular central incisor: Middle is 22 mm long, of which 9 mm coronal and root 13, and has a relatively narrow diameter (6 mm) vestibule-palate facing a mesial-distal 6.5 mm. The crown / root ratio indicates that it is a tooth with a strong anchor, in order to resist the masticatory functions performed.

Arrangement and relations:
The incisal upper side is in contact with the central incisal mesial distal side, distal to the mesial side of the canine. The points of contact are very high, between the middle third and third cervical of the crown. With time and wear of the teeth this contact becomes an elliptical surface rather elongated in the corono-apical cervical direction.

Coronal morphology:
vestibular It is symmetrical: the distal margin is however shorter than the most mesial about 2 mm, and clearly convex. The incisal margin of its center is slightly inclined to join the edges of the element. Superficially the buccal surface is convex and crossed by two depressions which give rise to three lobes whose distal end is more extensive. Near the cervix, then in the third cervix, they notice the roughness called cervical ridges.
palatal They are marked by marginal ridges on the mesial, distal sides, or larger thicknesses of the contour element enamel layer that determine the formation of a central pit. Cervical is a belt or heel, often separated by a throat from the rest of the element.
distal and mesial the element does not have large differences, with the exception of the greater length of the mesial side compared to the distal end of the order of 2 mm, with the rather convex and concave vestibular margin of the lingual side until the third cervix when the robot determines a convexity. The observation of these aspects, it should be noted that the incisal margin is on the same axis
incisal It has a variable shape, sometimes more similar to the upper central incisor, the other superior canine. The vestibular margin is clearly convex, which is characterized by the distal concavity, mesial and distal, which connect the tubercle, decidedly convex. It presents with an ovoid shape, with its axis along the mesial-distal.

Morphology root:
The incisor upper side is monoradicolato: The trunk of the root is half cylindrical coronal, a little narrower than the crown; at the mid narrows sharply to disappear to the tip, curving distally in 53% of cases, or directly in 30%. The root of the superior lateral incisor is proportionally longer than the central one; It is also more flattened in the medio-distal direction, with a fairly sharp summit, and sometimes curved in the distal direction. Ladice is crossed by a single channel in 99.9% of cases; in 10% of the cases of the main branch of the channel of side channels, in 12% of cases, the ramifications are apical. In young dental pulp, it is very wide, especially in the vestibule-palatal direction. Over time, the apposition of tertiary dentin reduces the cavity of the pulp which tends to be rounded.

odontogenesis:
The calcification of the crown begins about 10 months and was completed about 4-5 years. The tooth erupts around the age of 8, replacing the deciduous leaves, and root development is complete within 11 years.
Deciduous leaves erupt at 6 months.