Learning objective: to study the peculiarities of the anatomical structure of frontal mandibular teeth, to learn to identify the distinctive features of teeth belonging to the right or left side.
CENTRAL LOWER INCISOR
The vestibular surface is chisel-shaped with three ridges (longitudinal, medial and distal) forming two grooves: medial and distal. The height of contour and corners of the crown are distinguished. The anatomical neck of the tooth is clearly pronounced (fig. 11.1).
From the oral surface, which has a chisel shape, three ridges are distinguished: longitudinal, medial, distal. The anatomical neck of the tooth is well pronounced (fig. 11.2).
Lateral surfaces are of triangular shape with vestibular and lingual contours (fig. 11.3).
The tooth cavity is similar to the shape of the tooth, the root canal is usually split into two.
The root is comparatively short and thin. It is consolidated in the medio-lateral direction, there are grooves along the root. The lateral groove is expressed better than the medial groove. On the cross cut it shows an elongated oval.
The following distinctive signs are not well pronounced.
► Crown height 7-9.5 mm.
► Width 5-5.5 mm.
► Medio-distal diameter of the neck of the tooth 3.5-5 mm.
► Vestibulo-lingual diameter of the neck of the tooth 5.5-6 mm.
► The root length is 10.5-14 mm.
LATERAL LOWER INCISOR
Its vestibular surface is of trapezoidal shape, on which three rolls are distinguished: longitudinal, medial, distal, with medial and distal depressions, and the height of contour (fig. 11.4).
On the oral surface, trapezoidal, three rollers are distinguished: longitudinal, medial, distal, and lingual tubercle (fig. 11.5).
Lateral surfaces are of triangular shape with vestibular and lingual contours. On all surfaces there is a well-defined anatomical neck of the tooth (fig. 11.6).