Permanent Maxillary 1st Premolar

Summary

The maxillary first premolar is a key tooth in the upper arch, playing an important role in both tearing and grinding food. It is described in detail in terms of its development, morphology, and measurements. The script explains the structure of the tooth from various aspects, including the buccal, lingual, mesial, distal, and occlusal views. Additionally, it covers clinical considerations such as developmental anomalies like dens evaginatus and the role of the maxillary first premolar in orthodontic extractions. This comprehensive overview offers insight into both the functional and anatomical features of the tooth.

Takeaways

• 😀 The maxillary first premolar is the 4th tooth from the midline with different numbering systems in FDI, Universal, and Zsygmondy Palmar systems.
• 😀 Premolars, also called bicuspids, assist the canine in tearing and molars in grinding, with their function dependent on both cusps.
• 😀 The maxillary first premolar develops from four developmental lobes: mesial, buccal, distal, and lingual.
• 😀 The lingual lobe of the maxillary first premolar gradually increases in size from incisors to premolars, with changes in the marginal ridges.
• 😀 The age of eruption for the maxillary first premolar is between 10 and 11 years.
• 😀 The mesio-distal diameter of the crown at the contact area is 7 mm, and at the cervix, it is 5 mm.
• 😀 From the buccal aspect, the maxillary first premolar has a trapezoidal crown shape with a prominent buccal ridge.
• 😀 The mesial outline of the tooth is more concave than the distal outline, and both contact areas are located in the middle third of the crown.
• 😀 The mesial aspect reveals a trapezoidal crown with visible buccal and lingual cusps, and a developmental groove on the mesial marginal ridge.
• 😀 The occlusal view shows a hexagonal crown with two triangular ridges and four cuspal ridges, along with developmental grooves.
• 😀 Dens evaginatus, an anomaly with an extra tubercle between the buccal and lingual cusp, is common in premolars and is known as 'Leong's premolar'.

Q & A

What is the position of the maxillary first premolar in the mouth?

The maxillary first premolar is the 4th tooth from the midline.

What is the tooth number of the maxillary first premolar in different systems?

In the FDI system, the tooth numbers are 14 and 24. In the Universal System, it is 5 and 12. In the Zsigmondy Palmar System, it is represented by 4.

Why are premolars also called bicuspids?

Premolars are often called bicuspids because they have two cusps, although this term becomes inaccurate for mandibular premolars.

How many developmental lobes does the maxillary first premolar develop from?

The maxillary first premolar develops from four developmental lobes: mesial, buccal, distal, and lingual.

What are the developmental lobes of the maxillary first premolar responsible for?

The buccal lobe forms the buccal cusp, the lingual lobe forms the lingual cusp, the mesial lobe forms the mesial marginal ridge, and the distal lobe forms the distal marginal ridge.

How does the development of the lingual lobe change from incisors to premolars?

The development of the lingual lobe gradually increases from forming a small cingulum in incisors to a larger cingulum in canines, a lingual cusp smaller than the buccal cusp in the first premolar, and a lingual cusp equal to the buccal cusp in the second premolar.

What is the dual function of the maxillary first premolar?

The maxillary first premolar assists the canine in tearing with its sharp buccal cusp and helps molars in grinding by its occlusal surface.

At what age does the maxillary first premolar typically erupt?

The maxillary first premolar typically erupts between the ages of 10 and 11 years.

What is the general shape of the maxillary first premolar's crown when viewed from the buccal aspect?

The crown outline from the buccal aspect is trapezoidal, with the longer parallel side towards the cusp and the shorter side towards the cervix.

What are some distinguishing features of the maxillary first premolar's occlusal surface?

From the occlusal aspect, the maxillary first premolar has a hexagonal outline, with ridges including two triangular ridges, four cuspal ridges, two marginal ridges, and two triangular concavities (mesial and distal triangular fossae). It also features several developmental grooves and pits.