Tooth Morphology Notes|Premolars and Molars|BDS
Introduction
Understanding the morphology of molars and premolars is essential for dental
professionals to diagnose and treat different oral health conditions.
Premolars – also know as Bicuspids
There are no premolars found in the primary dentition and in the permanent dentition
there are 8 premolars.
Premolars are smaller than molars, with more pointed cusps and narrower occlusal
surfaces. Buccal and palatal/lingual cusps are found on premolars. Premolars typically
have one or two roots. Maxillary premolars usually have two roots (buccal and palatal),
and the mandibular premolars have one root.
Premolars are distal to the canines, anterior to the molars.
Molars
There are 8 molars in the primary (deciduous) dentition and 12 molars in the permanent
dentition.
Molars are flat, large teeth with a broad occlusal outline. These teeth comprise of four or
five cusps of which are situated on the mesio-buccal, disto-buccal, mesic-lingual
surfaces of the tooth. On some occasions, there is an additional cusp on the maxillary
molars called the cusp of carabelli (which makes the fifth cusp). Molars are typically
found in the posterior part of the mouth.
Molars have two or three roots depending on the the tooth. Maxillary molars usually
have three roots (mesiobuccal, distobuccal and palatal) and mandibular molars have
two roots (mesial and distal)
Molars are distal to premolars.
Terminologies:
1. Cusp- pronounced elevation which is pointed mostly found on the occlusal
surface of the tooth
2. Ridge- long linear elevation on the surface of the teeth and is named according
to its location and form
3. Marginal ridge- rounded mesial and distal enamel borders of the the occlusal
surface of molars and premolars.
4. Triangular ridge- a ridge that descends from the cusps of the molars and
premolars to the central part of the occlusal surface.
5. Oblique ridge- variable ridge that crosses the occlusal surface of molars
obliquely.
, 6. Transverse ridge- a ridge formed when a buccal and lingual ridge join.
7. Fossa- a rounded or angular depression on a tooth surface mostly seen on the
occlusal surface of molars.
8. Groove- shallow long shaped depression in the form of a line on a tooth surface
9. Long axis of the tooth- a 2D imaginary line that runs through the top of the cusp
or the middle point of the crown and the apex or middle of the root.
Fossa
Long axis of the tooth
Groove
Marginal ridge
Introduction
Understanding the morphology of molars and premolars is essential for dental
professionals to diagnose and treat different oral health conditions.
Premolars – also know as Bicuspids
There are no premolars found in the primary dentition and in the permanent dentition
there are 8 premolars.
Premolars are smaller than molars, with more pointed cusps and narrower occlusal
surfaces. Buccal and palatal/lingual cusps are found on premolars. Premolars typically
have one or two roots. Maxillary premolars usually have two roots (buccal and palatal),
and the mandibular premolars have one root.
Premolars are distal to the canines, anterior to the molars.
Molars
There are 8 molars in the primary (deciduous) dentition and 12 molars in the permanent
dentition.
Molars are flat, large teeth with a broad occlusal outline. These teeth comprise of four or
five cusps of which are situated on the mesio-buccal, disto-buccal, mesic-lingual
surfaces of the tooth. On some occasions, there is an additional cusp on the maxillary
molars called the cusp of carabelli (which makes the fifth cusp). Molars are typically
found in the posterior part of the mouth.
Molars have two or three roots depending on the the tooth. Maxillary molars usually
have three roots (mesiobuccal, distobuccal and palatal) and mandibular molars have
two roots (mesial and distal)
Molars are distal to premolars.
Terminologies:
1. Cusp- pronounced elevation which is pointed mostly found on the occlusal
surface of the tooth
2. Ridge- long linear elevation on the surface of the teeth and is named according
to its location and form
3. Marginal ridge- rounded mesial and distal enamel borders of the the occlusal
surface of molars and premolars.
4. Triangular ridge- a ridge that descends from the cusps of the molars and
premolars to the central part of the occlusal surface.
5. Oblique ridge- variable ridge that crosses the occlusal surface of molars
obliquely.
, 6. Transverse ridge- a ridge formed when a buccal and lingual ridge join.
7. Fossa- a rounded or angular depression on a tooth surface mostly seen on the
occlusal surface of molars.
8. Groove- shallow long shaped depression in the form of a line on a tooth surface
9. Long axis of the tooth- a 2D imaginary line that runs through the top of the cusp
or the middle point of the crown and the apex or middle of the root.
Fossa
Long axis of the tooth
Groove
Marginal ridge
