Incisive tooth. The incisors are the eight teeth that people have in the front and center of the mouth (four at the top and another four at the bottom). These are the teeth that are normally used to nibble food and cut it. Normally, the incisors are the first teeth to emerge, around 6 months of age in the case of milk teeth , and between 6 and 8 years of age, together with the six-year-old molar in the case of teeth. definitive .
Summary
[ hide ]
- 1 Location
- 2 Symbolism
- 1 Deciduous Teeth Parts
- 2 Pieces of permanent dentition
- 3 Superior Central Incisor
- 1 Dental contacts
- 4 Upper Lateral Incisor
- 1 Dental contacts
- 5 Lower Central Incisor
- 6 Lower Lateral Incisor
- 7 Sources
Location
The incisors are located in both dental arches in the anterior area, on both sides of the midline. The human being has 4 upper incisors and 4 lower incisors, 2 central and 2 lateral ones in the maxilla and as many in the mandible. The central incisors are those that are on both sides of the midline, they are usually called the paletos or paletas because of their resemblance to a shovel, on both sides of the central ones are the lateral incisors.
In a frontal view they are seen from left to right: right canine, right lateral incisor, right central incisor, left central incisor, left lateral incisor and left canine. Agenesis, or absence, or the appearance of a conoid in the upper lateral incisor is relatively frequent. It has a rectangular or trapezoidal crown seen from its vestibular free faces, and lingual looking from mesial or distal, it is wedge-shaped and converges towards the dental neck.
Symbolodontics
According to symbolism, in the Universal System of the ADA (American Dental Association) they are called:
Deciduous Teeth Parts
- 4p: Right upper lateral incisor.
- 5p: Right upper central incisor.
- 6p: Left upper central incisor.
- 7p: Left upper lateral incisor.
- 14p: Lower left lateral incisor.
- 15p: Lower left central incisor.
- 16p: Lower right central incisor.
- 17p: Lower right lateral incisor.
Permanent Teeth Parts
- 7: Right upper lateral incisor.
- 8: Right upper central incisor.
- 9: Left upper central incisor.
- 10: Left upper lateral incisor.
- 23: Lower left lateral incisor.
- 24: Lower left central incisor.
- 25: Lower right central incisor.
- 26: Lower right lateral incisor.
Superior Central Incisor
It has a very important role in the anterior sector because it is the main determining factor of the individual’s dental aesthetics. It has a trapezoidal crown, has a single root and has a greater vestibulolingual dimension than the distal mesio. It is the largest incisor of all, and its cervical incisional crown length is the longest of all human dentition.
By joining the incisal edge with the proximal faces, it forms two angles, one mesioincisal, in a lower plane and with a more marked vertex (angle of 90º), and the other, distoincisal, in a more rounded and superior plane.
Palatal face: the trapezoidal shape is exaggerated by the greater convergence of the proximal sides. It presents in its central portion and in the incisal and middle thirds a depression, delimited above by the cingulum (cervicopalatine process or 4th lobe), and laterally by the marginal ridges, reaching the respective angle only the mesial rim.
Dental contacts
- Proximal contacts: through its mesial aspect it contacts the contralateral upper central incisor, and through its distal aspect it contacts the mesial aspect of the corresponding lateral incisor.
- Occlusal contacts: its palatal face contacts the incisal edge of the lower central incisors.
On its vestibular face it has a trilobed incisal edge on the newly erupted teeth and with two notches, mesial and distal. It has a cingulum on its palatal face, that is, a hemispherical bulge located in the cervical third, which corresponds to the fourth tooth formation mamelon. It has a single root, 1.25-1.50 times the coronary length, conical in shape, smooth surface, rarely presents grooves, most often it is straight, although sometimes it presents curvatures in the apical third and towards distal. It usually has 3 pulpal horns on young teeth.
Superior Lateral Incisor
It is in the process of evolutionary reduction or disappearance, it is frequent that it does not appear, one or both, or in the form of a conoid tooth. This process of reduction or disappearance is also common in the third molar. It has a trapezoidal, single-root shape, is smaller than the upper central incisor, and its vestibulolingual dimension is smaller than the mesiodistal. The incisocervical dimension is much larger than the mesiodistal.
Dental contacts
- Proximal: it is located distally to the superior canineand mesially to the superior central incisor.
- Occlusal: it contacts the distal half of the lower lateral incisor and the mesial half of the lower canine.
Like the upper central incisor, it has a circle on its palatal face. It has a single root, sometimes it has grooves on its mesial and distal face, it is very common that the root of the upper lateral incisor presents a curvature in its apical third, almost always with distal and palatal direction.
Lower Central Incisor
His dental contacts are:
- Proximal: contacted mesially with the contralateral central incisor and distally with the lateral incisor on the same side.
- Occlusal: its incisal edge contacts the palatal aspect of the upper central incisor. It is, along with the upper third molar, the only tooth that occludes with a single antagonist and not two.
It has a unique root that may have a slight convexity towards the vestibular and its most characteristic feature is that it has a distal mesial crush.
Lower Lateral Incisor
It is very similar to the lower central incisor, slightly larger than the previous one, and its distal portion of the incisal edge is more rounded, thus removing the symmetry of the central one. It has a single flattened mesiodistal root that may not have a groove on the mesial side, but always exists on the distal side. The apical third of the root usually has a slight deviation to the distal. It has the root slightly turned lingual and distal. They serve to sustain what will be ingested
