Dental Anatomy and Occlusion: Maxillary Premolars Pulp Cavities

Maxillary Premolars

• Pulp chamber of the maxillary first premolar is wider buccolingually than mesiodistally.
• Roots of the maxillary first premolar: 70% have two roots with separate foramina, and less than 10% possess a single canal.
• Buccolingual section: pulp chamber is square or rectangular with two prominent pulp horns (buccal and lingual).
• Mesiodistal section: pulp chamber is narrower than buccolingually, similar to the maxillary canine.
• Cervical cross section: root outline is wider buccolingually and kidney-shaped, with two orifices in most cases, the lingual orifice being slightly larger.
• Mid-root cross section: hour-glass appearance.

Maxillary Second Premolar

• Typically has one root and one root canal.
• Often, the canal branches in the apical third, with two foramina.
• Buccolingual section: pulp chamber has two pulp horns, with the buccal horn usually larger.
• Pulp canals: taper regularly to the apical third, where it becomes constricted.
• Foramen is normally larger than either of the foramina of the first premolar.
• Rarely, there may be two roots and two root canals, similar to the first premolar.

Mandibular Premolars

• Pulp cavity of the mandibular first premolar is wider buccolingually than mesiodistally.
• Buccolingual section: pulp chamber has two pulp horns, with a large and pointed buccal horn, and a small rounded lingual horn.
• Pulp canal: tapers rather evenly to the apical third, where it is constricted to its apical termination.
• Mesiodistal section: similar to the mandibular canine, although the canine has a longer root and pulp canal.
• Cervical cross section: both root and root canal are normally ovoid and wider buccolingually.
• Mid-root cross section: canal outline is normally round.

Mandibular Second Premolar

• Similar to the mandibular first premolar, except:
  • The lingual pulp horn is normally larger.
  • Some Y-type specimens exhibit two lingual pulp horns.
  • The root and root canal cross sections are more often ovoid.
  • The pulp chamber is relatively wider buccolingually than mesiodistally.
  • The root and root canal are slightly longer.