Dental Anatomy: Maxillary and Mandibular Molars

Maxillary and Mandibular Second and Third Molars

• Maxillary second molars supplement the first molar in function
• Maxillary second molar roots are as long or slightly longer than those of the first molar
• The distobuccal cusp of the maxillary second molar is smaller and less developed compared to the first molar
• The maxillary second molar crown is 0.5mm shorter cervico-occlusally than the first molar
• The buccal-lingual dimension of the maxillary second molar is similar to the first molar, but the crown length is less
• Two types: rhomboidal type (resembles first molar) and heart-shaped type (resembles third molar)
• Maxillary second molar typically has a crown which is shorter cervico-occlusally and narrower mesiodistally than the max first molar.
• The distobuccal cusp is smaller in the max 2nd molar, and more of mesiobuccal cusp may be seen (from a certain angle)
• The mesiolingual cusp is not usually visible.
• The apex of the lingual root is in line with the distolingual cusp.
• No fifth cusp is visible on the maxillary second molar
• The apex of the mesiobuccal root is in line with the buccal groove, unlike the first molar which is at tip of mesiobuccal cusp
• Maxillary third molars resemble and supplement the second molar function
• Maxillary third molar crowns are smaller and their roots shorter than the second molar.
• The occlusal surface of the third molar is heart-shaped
• They exhibit more variation in development
• The age of eruption of maxillary third molars is typically between 17 and 21 years
• Maxillary third molar crown is shorter cervicoocclusally and narrower mesiodistally than the second molar.
• The root is fused at the apex, tapering more pointedly cervico-apical than the second molar
• A single large lingual cusp without lingual groove is present.
• Mesial aspect tapers to the fused roots, with a poorly developed apical third and irregular outline.
• Distal aspect has most of the buccal crown surface is visible at distal aspect due to acute angulation of occlusal surface.
• The occlusal aspect is almost heart-shaped, possessing 3 functioning cusps (2 buccal, 1 lingual).
• Rhomboidal outline with 4 functioning cusps is also present.

Mandibular Second Molar

• Mandibular second molars supplement the first molar in function
• Four well-developed cusps (two buccal, two lingual)
• Distobuccal cusp is larger than the first molar
• Two well-developed, widely separated roots (mesial and distal)
• The crown is shorter cervicobuccally and narrower mesiodistally than the first molar
• The buccal developmental groove divides the mesiobuccal and distobuccal cusps, which are equal in size
• Two roots, (mesial and distal), are less broad and closer together than in the first molar.
• They are shorter, angled distally more than those in the first molar.
• Tips of lingual cusps are higher than the buccal cusps.
• Cervical ridge is less pronounced, and the occlusal surface is constricted buccolingually in the second molar.
• No curvature is present in the cervical line.
• Two roots are visible in the mesial.
• Roots are pointed apically.
• Absence of distal cusp and distobuccal groove.
• Most of occlusal surface can be seen from distal aspect
• The contact area is centered on the distal surface buccolingually, equidistant from the cervical line and marginal ridge
• Roughly rectangular in shape
• Central groove in the center with lingual and buccal grooves meeting with the central groove at right angle.
• Four cusps, two buccal (mesiobuccal and distobuccal), and two lingual (mesiolingual, and distolingual)
• Buccolingual grooves meet the central developmental groove at right angles at the central pit
• Exhibit more curvature of outline of crown distally than mesially, showing a semi-circular outline to the disto-occlusal surface compared with a square outline mesially.

Mandibular Third Molar

• Presents significant anomalies in form and positioning
• Supplements the second molar in function
• Rarely well-developed
• 5 or more cusps sometimes present
• Buccal aspect shows variation in outline, with a wider crown at contact areas mesiodistally than the cervix.
• Crown is shorter with rounded buccal cusps.
• Two roots, mesial and distal, can be shorter and poorly developed; they sometimes fuse partially along their length
• Lingual aspect similar to the second molar, but the size and root developments vary.
• Mesial aspect similar to second molars, but roots are shorter and taper more from the cervix to the apex and are more pointed.
• Distal aspect shows a more spheroidal form above the cervical line.
• Distal root appears smaller in length and buccolingual measurement
• Occlusal aspect is more rounded with smaller buccolingual measurement distally.

Test your knowledge of dental anatomy with this quiz focused on the characteristics of maxillary and mandibular molars. Explore key differences, root structures, and occlusal surfaces that define these important teeth. Perfect for dental students and professionals alike.