What Are Mandibular Molars?
The mandibular first molar is the earliest tooth eruption in permanent teeth, which is about 6 years old. It is also called "sixth-age tooth", which is the larger tooth in the mandibular arch.
Mandibular first molar
Right!
- Chinese name
- Mandibular first molar
- Foreign name
- mandibular first molar
- Time
- Around 6 years old
- nickname
- Sixth age tooth
- The mandibular first molar is the earliest tooth eruption in permanent teeth, which is about 6 years old. It is also called "sixth-age tooth", which is the larger tooth in the mandibular arch.
(1) Buccal surface: It is slightly trapezoidal. The occlusal margin is longer than the neck margin. The occlusal margins can be seen at the mesial, distal, and distal apical cusps, which are separated from the buccal groove and the distal buccal groove, respectively. The buccal axillary ridge of the mesial and distal buccal apex is parallel to the buccal groove. The buccal neck is parallel to the rim of the neck. The height of the contour is 1/3 of the cheek and neck.
(2) Tongue surface: It looks like a trapezoid, smaller than the buccal surface and slightly rounded. The occlusal margin shows the mesial tongue tip and the distal tongue tip. The tongue groove is picked through the two tongue tips, and the tongue axis is not obvious. The height of the contour is 1/3 in the tongue.
(3) Adjacent surface: It looks like a quadrangle, the crown of the tooth is inclined to the tongue side, and the tip of the cheek is lower than the tip of the tongue. The mesial plane is smaller than the mesial plane. The mesial cheek-neck angle and mesial tongue angle are sharper. The mesial and distal contact areas are close to the occlusal 1/3 partial buccal side.
(4) occlusal surface: complex morphology, the teeth with the most occlusal apex, palate, fossa, groove, and slope. The mesial diameter is greater than the buccal tongue diameter, and the outline is slightly rectangular.
Marginal ridge: The occlusal surface is surrounded by four marginal ridges. The buccal occlusal ridge is longer than the lingual occlusal ridge, the mesial edge is longer and straighter, and the distal medullar ridge is shorter and protruding.
Tips: There are 5 tips. The tip of the cheek is short and blunt, the tip of the tongue is long and sharp, the distal tip is the smallest, and it is located at the junction of the cheek surface and the distal surface.
Triangular ridge: There are 5 triangular ridges extending to the center of the occlusal surface.
Fossa and point gap: The occlusal surface has a central fossa and a mesial fossa. The central fossa is located in the mesial cheeks, the apex of the triangular ridge of the tongue tip and the medial margin of the iliac crest. The smaller triangular fossa of the medial marginal iliac crest and the mesial cheek and the apical triangular crest. There is a near-midpoint gap in the fossa.
Ditch: There are five development grooves. The buccal groove extends from the central point gap to the buccal side, forming a point gap between the mesial and distal cheek tips to the buccal surface, and the end forms a point gap; the tongue groove extends from the central point gap to the tongue surface between the mesial and distal tongue tips; mesial The ditch extends from the central point gap to the mesial and ends in the mesial marginal ridge; the distant ditch extends from the central point gap to the distant and ends in the distant marginal ridge; the far buccal ditch separates from the distant ditch and since the distant The distance between the middle cheek tip and the distal midpoint is toward the cheek to the cheek.
Bevel: Each apex has four bevels, of which the lingual bevel of the tongue tip is in occlusal contact with the maxillary teeth, and the buccal bevel of the tongue tip and the buccal tip and the distal and apex are in occlusal contact.
The roots are flat and thick with short roots. The mesial root is slightly larger than the mesial root, and the mesial and mesial roots have elongated depressions; the mesial roots have elongated depressions only on the mesial roots. The apex is distant. The distal root is evenly divided into cheek and tongue, and the distal tongue is short and curved.