Deciduous Maxillary First Molar

The deciduous maxillary first molar is smaller than the deciduous maxillary second molar. According to the shape, this tooth is an intermediate between a premolar and a molar. Together with the mandibular molars, the deciduous maxillary molars perform the grinding function.

Development and Eruption

Following is a summary of the development and eruption of the deciduous maxillary first molar.

• Initiation of calcification: 15 weeks in utero
• Completion of the crown: 6 months
• Eruption of tooth: 16 months
• Root completion: 2.5 years
• Exfoliation of tooth: 10 years

The deciduous maxillary first molar is replaced by the maxillary first premolar.

Buccal Aspect

• The buccal surface of the deciduous maxillary first molar is smooth with very few indistinct developmental grooves.
• The deciduous maxillary first molar is widest at the contact areas.
• There are three roots and all are visible from the buccal aspects. The name of the roots is the mesial root, distal root, and palatal root. The distal root is shorter as compared to the mesial root, and the palatal root is the longest.
• The roots of this tooth are slender, long, and widely separated.
• The root trunk in the deciduous maxillary first molar is not very well developed. The division of the root begins just below the cementoenamel junction.

Lingual Aspect

• The crown converges considerably towards the lingual aspect. Therefore, part of the mesial and the distal aspect of the tooth is visible from the lingual aspect.
• The mesiolingual cusp is the most prominent and sharp while the distolingual cusp is smooth and rounded.
• The distobuccal cusp is visible because it is long and well developed as compared to the distolingual cusp.
• In a three cusp type deciduous maxillary first molar there are two buccal cusps and a large single lingual cusp is present.
• All three roots mesial, distal, and palatal are visible from the lingual aspect. The palatal root is the largest.

Mesial Aspect

• The mesiolingual cusp of the deciduous maxillary first molar is longer and shaper as compared to the mesiobuccal cusp.
• The mesial marginal ridge connects the mesiolingual cusp with the mesiobuccal cusp.
• The tooth has a pronounced convexity on the buccal surface at the cervical third of the crown.
• The cervical line show curvature towards the occlusal surface.
• The lingual root extends lingually. Above one-third of the root the lingual root curves sharply in a buccal direction.

Distal Aspect

• The crown of the deciduous maxillary first molar is narrow on the distal aspect as compared to the mesial aspect. Therefore, parts of the buccal and lingual aspects of the tooth are visible from the distal aspect.
• The distobuccal cusp is long and sharp as compared to the distolingual cusp which is small and rounded.
• Due to small distobuccal and distolingual cusps parts of the mesiobuccal and the mesiolingual cusps are visible from the distal aspect.
• The cervical line extends nearly straight from the buccal to the lingual surface of the tooth.
• Part of the mesiobuccal root is also visible from the distal aspect.

Occlusal Aspect

• The crown of the deciduous maxillary first molar converges towards the lingual aspect.
• The crown also converges towards the distal aspect.
• The occlusal surface has a central fossa, mesial triangular fossa, and smallest distal triangular fossa.
• The central developmental groove extends from the mesial triangular fossa to the distal triangular fossa.
• Many supplementary grooves arise from the central developmental groove.
• Among the mesial and the distal marginal ridges, the distal marginal ridge is thin and not very well developed.

Video Lecture explaining the morphology of the deciduous maxillary first molar

Demonstration of the Morphology of the deciduous maxillary first molar