Molars are the primary or main teeth which help in chewing of food in both Primary and Permanent Dentition. There are 6 Molars (1st, 2nd and 3rd Molars or Wisdom teeth) in Permanent Maxillary and 6 Molars (1st, 2nd and 3rd Molars or Wisdom teeth) in Permanent Mandibular dentition. Whereas in the Primary or Deciduous dentition we have 1st and 2nd Molars. The permanent First molars are one of the first to erupt in the mandibular dentition alongside the incisors. Here we are discussing or will be seeing the differences between the Maxillary and Mandibular 1st and 2nd molars only and not the 3rd molars, as they are usually unusual in shape and size in all aspects.
It is important to know the shape and location of the cusps, ridges and other aspects as it helps in Cavity preparation, Access Cavity Opening and also in Crown cutting for any Crown to be placed.
Differences between Permanent Maxillary and Mandibular Molars:
Maxillary Molars: Have three roots
Mandibular Molars: Have two roots
—————————————–
Maxillary Molars: Shape of the Crown is Square
Mandibular Molars: Shape of the Crown is Pentagon
—————————————–
Maxillary Molars: Have two buccal cusps
Mandibular Molars: Have two or three buccal cusps
—————————————–
Maxillary Molars: Have one buccal groove
Mandibular Molars: Have two buccal grooves on the first molar and a single buccal groove on the second and third molars
—————————————–
Maxillary Molars: Root Trunk is larger
Mandibular Molars: Root Trunk is smaller
—————————————–
Maxillary Molars: Cusp of Carebelli is seen on the first molar
Mandibular Molar: No Cusp of Carebelli is seen
—————————————–
Maxillary Molars: The Crown tapers towards the Palatal aspect
Mandibular Molars: The Crown does not taper towards the Lingual aspect
—————————————–
Maxillary Molars: Oblique ridge is seen in both molars
Mandibular Molars: Oblique ridge is absent in both molars
—————————————–
Maxillary Molars: The Long Axis of Root and Crown portion are in sync with each other
Mandibular Molars: The Crown is tipped towards the lingual aspect when compared to the long axis of the Root
—————————————–
Maxillary Molars: Due to the number of cusps and their position, there in only one Transverse ridge
Mandibular Molars: There are two Transverse ridges
—————————————–
Maxillary Molars: The Shape of the Crown is Square when seeing from above
Mandibular Molars: The Crown is in the shape of Pentagon when seen from above
—————————————–
Maxillary Molars: Number of Fossae are four with large central one while the Distal one is a cigar shared one
Mandibular Molars: Number of fossae are three while the central one is the largest of the three
—————————————–
Maxillary Molars: These have four well formed cusps – 2 buccal and 2 lingual cusps along with Cusp of Carabelli (small supplemental cusp)
Mandibular Molars: These have two Lingual cusps and three Buccal Cusps
It is important for a Clinician to know the precise anatomy of the Molars of Maxillary and Mandible as it helps in many aspects of treatments such as – Cavity preparation, Access Openings, Crown cutting, etc. Knowing the correct anatomy of all the teeth help us in keeping in mind the location of canals to prevent loosing healthy dentin and preserving as much of natural tooth structure as possible.
