Location and Function of the Mandibular Second Molar
- The mandibular second molar is located distally from the mandibular first molars and mesial from the mandibular third molars.
- It is involved in grinding during mastication.
- There are usually four cusps on mandibular second molars - two on the buccal side and two on the lingual side.
- The function of permanent mandibular molars is similar to that of deciduous molars.
- Permanent mandibular molars do not have any teeth preceding them.
Notation for Deciduous Mandibular Second Molars
- In the universal system of notation, the right deciduous mandibular second molar is designated as T, and the left one as K.
- The international notation uses numbers - the right deciduous mandibular second molar is known as 85, and the left one as 75.
Notation for Permanent Mandibular Second Molars
- In the universal system of notation, the right permanent mandibular second molar is designated as 31, and the left one as 18.
- The Palmer notation uses a number and a symbol to indicate the quadrant - both second molars have the number 7, with the right one having the symbol ┐ and the left one having ┌.
- The international notation uses different numbers - the right permanent mandibular second molar is known as 47, and the left one as 37.
Additional Cusp
- An eighth cusp was discovered in a primary second lower molar in an Argentinean child.
- This finding suggests variations in tooth morphology.
References
- Ash, Major M. and Stanley J. Nelson, 2003. 'Wheelers Dental Anatomy, Physiology, and Occlusion.' 8th edition.
- Rodriguez-Florez, C.D. et al., 2006. 'Occurrence of an Eighth Cusp on Primary Second Mandibular Molars of a Contemporary Argentinean Child.' Dental Anthropol 19(3): 83-85. (http://anthropology.osu.edu/DAA/back%20issues/DA%20Vol%2019%203.pdf)
The mandibular second molar is the tooth located distally (away from the midline of the face) from both the mandibular first molars of the mouth but mesial (toward the midline of the face) from both mandibular third molars. This is true only in permanent teeth. The function of this molar is similar to that of all molars in regard to grinding being the principal action during mastication, commonly known as chewing. Though there is more variation between individuals than that of the first mandibular molar, there are usually four cusps on mandibular second molars: two on the buccal (side nearest the cheek) and two lingual (side nearest the tongue). There are great differences between the deciduous (baby) mandibular molars and those of the permanent mandibular molars, even though their function is similar. The permanent mandibular molars are not considered to have any teeth that precede them. Despite being named molars, the deciduous molars are followed by permanent premolars.
| Mandibular second molar | |
|---|---|
 | |
| Identifiers | |
| FMA | 290277 |
| Anatomical terminology | |
In the universal system of notation, the deciduous mandibular second molars are designated by a letter written in uppercase. The right deciduous mandibular second molar is known as "T", and the left one is known as "K". The international notation has a different system of notation. Thus, the right deciduous mandibular second molar is known as "85", and the left one is known as "75".
In the universal system of notation, the permanent mandibular second molars are designated by a number. The right permanent mandibular second molar is known as "31", and the left one is known as "18". In the Palmer notation, a number is used in conjunction with a symbol designating in which quadrant the tooth is found. For this tooth, the left and right second molars would have the same number, "7", but the right one would have the symbol, "┐", underneath it, while the left one would have, "┌". The international notation has a different numbering system from the previous two, and the right permanent mandibular second molar is known as "47", and the left one is known as "37".
An eighth cusp was found in a primary second lower molar in an Argentinean child.
