FORENSICS

Dentition: Molars

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Molars are multiple-rooted teeth with wide and low crowns characterized by the most complex occlusal morphology of all the tooth classes.  Molars are larger than the other tooth classes, and their occlusal outline is more rectangular.  Each molar bears three to five major bulbous cusps arranged in a consistent pattern.  Multiple crests descend from each of the major cusps, and are named for their position on the cusp with which they are associated. As for all teeth and bones, inter-individual variability exists for molar occlusal morphology.  Variability in morphology increases from M1 to M3.  M1 is the least variable, while variability increases in M2.  M3 is extremely variable in morphology and size.  Congenital absence of M3 is also more common than any other tooth.

More teeth specimens can be found in the digital teaching collection.  See also the incisors, canines, and premolars.




Maxillary Molar 1


Max. Molar 2


Max. Molar 3


Mandibular Molar 1


Man. Molar 2


Man. Molar 3



Maxillary molars have an occlusal outline which is shaped like a rhombus, or an obliquely deflected square.  They most often have three roots: two buccal roots and a single lingual root.  Typically maxillary molars bear four (but sometimes only three) major cusps.  The major cusps are asymmetrical in their position with regards to the perpendicular axes of the tooth. The major cusps are found in two pairs, one pair occupying the buccal occlusal margin and one pair occupying the lingual occlusal margin.  Maxillary molars have an occlusal outline which is shaped like a rhombus, or an obliquely deflected square.  They most often have three roots: two buccal roots and a single lingual root.  Typically maxillary molars bear four (but sometimes only three) major cusps.  The major cusps are asymmetrical in their position with regards to the perpendicular axes of the tooth.

The major cusps are found in two pairs, one pair occupying the buccal occlusal margin and one pair occupying the lingual occlusal margin.  The paracone is the mesial cusp in the buccal row.  The metacone is the distal cusp in the buccal row.  The paracone and metacone are similar in size.  Together, the buccal cusps generally project higher than the lower and more worn cusps of the lingual row. The buccal cusps are separated by a deep buccal-lingually oriented buccal groove. The mesial part of the lingual row bears the protocone, the largest (in area) and most heavily worn of the cusps.  The distal part of the lingual row bears the hypocone, the smallest of the major maxillary cusps.  The hypocone is sometimes dramatically smaller than the other cusps or even totally absent.  When present, the hypocone is separated from the protocone by a deep buccal-lingually oriented lingual groove. Distinguishing between M1 and M2 can be difficult.  Usually, the molars decrease in size from M1-M3.  M2  typically has a reduced hypcone and metacone, giving the molar a more triangular occlusal outline.  M3 is exceedingly variable in both size and shape.  Its roots are commonly fused into a single bundle.  M3 usually lacks a hypocone. The occlusal surface of M3 is also commonly crenulated, lending a wrinkled appearance to the enamel surface.

Siding Molars

Molar teeth can usually be unambiguously sided.  Identification of the cusps is the key to siding molars.  Once a single cusp has been identified, reference the above descriptions to determine where on the tooth crown that cusp is located (e.g. the protocone is the mesial-lingual cusp).  Once the tooth has been roughly oriented in this manner, the identity of other cusps can be worked out, and the tooth may be easily sided. The protocone and protoconid are usually the largest and most heavily worn cusps.  When present, the hypocone is the smallest cusp on the upper molars.  Likewise, the hypoconid is usually the smallest cusp. The buccal and lingual cusp rows are unequal in height.  In the maxillary molars, the buccal cusp row is higher than the lingual.  In mandibular tooth rows, the lingual row is higher.  The roots of all molars have a tendency to tilt distally.


Maxillary molars have an occlusal outline which is shaped like a rhombus, or an obliquely deflected square.  They most often have three roots: two buccal roots and a single lingual root.  Typically maxillary molars bear four (but sometimes only three) major cusps.  The major cusps are asymmetrical in their position with regards to the perpendicular axes of the tooth. The major cusps are found in two pairs, one pair occupying the buccal occlusal margin and one pair occupying the lingual occlusal margin.  Maxillary molars have an occlusal outline which is shaped like a rhombus, or an obliquely deflected square.  They most often have three roots: two buccal roots and a single lingual root.  Typically maxillary molars bear four (but sometimes only three) major cusps.  The major cusps are asymmetrical in their position with regards to the perpendicular axes of the tooth.

The major cusps are found in two pairs, one pair occupying the buccal occlusal margin and one pair occupying the lingual occlusal margin.  The paracone is the mesial cusp in the buccal row.  The metacone is the distal cusp in the buccal row.  The paracone and metacone are similar in size.  Together, the buccal cusps generally project higher than the lower and more worn cusps of the lingual row. The buccal cusps are separated by a deep buccal-lingually oriented buccal groove. The mesial part of the lingual row bears the protocone, the largest (in area) and most heavily worn of the cusps.  The distal part of the lingual row bears the hypocone, the smallest of the major maxillary cusps.  The hypocone is sometimes dramatically smaller than the other cusps or even totally absent.  When present, the hypocone is separated from the protocone by a deep buccal-lingually oriented lingual groove. Distinguishing between M1 and M2 can be difficult.  Usually, the molars decrease in size from M1-M3.  M2  typically has a reduced hypcone and metacone, giving the molar a more triangular occlusal outline.  M3 is exceedingly variable in both size and shape.  Its roots are commonly fused into a single bundle.  M3 usually lacks a hypocone. The occlusal surface of M3 is also commonly crenulated, lending a wrinkled appearance to the enamel surface.

Siding Molars

Molar teeth can usually be unambiguously sided.  Identification of the cusps is the key to siding molars.  Once a single cusp has been identified, reference the above descriptions to determine where on the tooth crown that cusp is located (e.g. the protocone is the mesial-lingual cusp).  Once the tooth has been roughly oriented in this manner, the identity of other cusps can be worked out, and the tooth may be easily sided. The protocone and protoconid are usually the largest and most heavily worn cusps.  When present, the hypocone is the smallest cusp on the upper molars.  Likewise, the hypoconid is usually the smallest cusp. The buccal and lingual cusp rows are unequal in height.  In the maxillary molars, the buccal cusp row is higher than the lingual.  In mandibular tooth rows, the lingual row is higher.  The roots of all molars have a tendency to tilt distally.


Maxillary molars have an occlusal outline which is shaped like a rhombus, or an obliquely deflected square.  They most often have three roots: two buccal roots and a single lingual root.  Typically maxillary molars bear four (but sometimes only three) major cusps.  The major cusps are asymmetrical in their position with regards to the perpendicular axes of the tooth. The major cusps are found in two pairs, one pair occupying the buccal occlusal margin and one pair occupying the lingual occlusal margin.  Maxillary molars have an occlusal outline which is shaped like a rhombus, or an obliquely deflected square.  They most often have three roots: two buccal roots and a single lingual root.  Typically maxillary molars bear four (but sometimes only three) major cusps.  The major cusps are asymmetrical in their position with regards to the perpendicular axes of the tooth.

The major cusps are found in two pairs, one pair occupying the buccal occlusal margin and one pair occupying the lingual occlusal margin.  The paracone is the mesial cusp in the buccal row.  The metacone is the distal cusp in the buccal row.  The paracone and metacone are similar in size.  Together, the buccal cusps generally project higher than the lower and more worn cusps of the lingual row. The buccal cusps are separated by a deep buccal-lingually oriented buccal groove. The mesial part of the lingual row bears the protocone, the largest (in area) and most heavily worn of the cusps.  The distal part of the lingual row bears the hypocone, the smallest of the major maxillary cusps.  The hypocone is sometimes dramatically smaller than the other cusps or even totally absent.  When present, the hypocone is separated from the protocone by a deep buccal-lingually oriented lingual groove. Distinguishing between M1 and M2 can be difficult.  Usually, the molars decrease in size from M1-M3.  M2  typically has a reduced hypcone and metacone, giving the molar a more triangular occlusal outline.  M3 is exceedingly variable in both size and shape.  Its roots are commonly fused into a single bundle.  M3 usually lacks a hypocone. The occlusal surface of M3 is also commonly crenulated, lending a wrinkled appearance to the enamel surface.

Siding Molars

Molar teeth can usually be unambiguously sided.  Identification of the cusps is the key to siding molars.  Once a single cusp has been identified, reference the above descriptions to determine where on the tooth crown that cusp is located (e.g. the protocone is the mesial-lingual cusp).  Once the tooth has been roughly oriented in this manner, the identity of other cusps can be worked out, and the tooth may be easily sided. The protocone and protoconid are usually the largest and most heavily worn cusps.  When present, the hypocone is the smallest cusp on the upper molars.  Likewise, the hypoconid is usually the smallest cusp. The buccal and lingual cusp rows are unequal in height.  In the maxillary molars, the buccal cusp row is higher than the lingual.  In mandibular tooth rows, the lingual row is higher.  The roots of all molars have a tendency to tilt distally.

The occlusal outline of mandibular molars varies from square to a mesio-distally elongate oval.  Typical mandibular molars bear two roots, but occasionally three-rooted variants occur.  The two roots are often fused together. Mandibular molars bear four major cusps, arranged symmetrically around the major axes of the tooth. Lower molars often possess a smaller fifth cusp, and more rarely, a sixth cusp.  The four primary mandibular cusps are arranged in buccal and lingual rows, as in the maxillary molars.  The two major lingual cusps are the metaconid (mesial) and the entoconid (distal).  The two major buccal cusps are the protoconid (mesial) and the hypoconid (distal). The frequently present fifth cusp is the hypoconulid (more distal than the hypoconid). In some teeth, the hypoconulid is positioned more near the buccal-lingual midline; more commonly it is offset buccally toward the hypoconid.  When six cusps are present, the additional cusp is usually the entoconulid, which is a small cusp sandwiched between the entoconid and the hypoconulid. The pattern created by the grooves separating the cusps is classically termed the Y-5 pattern, because the groove separating the lingual and buccal cusp rows bifurcates into two grooves which course around the hypoconulid in a Y-shaped pattern.  However, this groove pattern is variable, and only occurs on teeth which actually bear a hypoconulid. It is just as difficult to distinguish M1 and M2 ­as it is for their maxillary counterparts.  As for maxillary molars, the mandibular molars usually decrease in size from M­1-M3.  M2 more frequently lacks a hypoconulid than M1.

Siding Molars

Molar teeth can usually be unambiguously sided.  Identification of the cusps is the key to siding molars.  Once a single cusp has been identified, reference the above descriptions to determine where on the tooth crown that cusp is located (e.g. the protocone is the mesial-lingual cusp).  Once the tooth has been roughly oriented in this manner, the identity of other cusps can be worked out, and the tooth may be easily sided. The protocone and protoconid are usually the largest and most heavily worn cusps.  When present, the hypocone is the smallest cusp on the upper molars.  Likewise, the hypoconid is usually the smallest cusp. The buccal and lingual cusp rows are unequal in height.  In the maxillary molars, the buccal cusp row is higher than the lingual.  In mandibular tooth rows, the lingual row is higher.  The roots of all molars have a tendency to tilt distally.


The occlusal outline of mandibular molars varies from square to a mesio-distally elongate oval.  Typical mandibular molars bear two roots, but occasionally three-rooted variants occur.  The two roots are often fused together. Mandibular molars bear four major cusps, arranged symmetrically around the major axes of the tooth. Lower molars often possess a smaller fifth cusp, and more rarely, a sixth cusp.  The four primary mandibular cusps are arranged in buccal and lingual rows, as in the maxillary molars.  The two major lingual cusps are the metaconid (mesial) and the entoconid (distal).  The two major buccal cusps are the protoconid (mesial) and the hypoconid (distal). The frequently present fifth cusp is the hypoconulid (more distal than the hypoconid). In some teeth, the hypoconulid is positioned more near the buccal-lingual midline; more commonly it is offset buccally toward the hypoconid.  When six cusps are present, the additional cusp is usually the entoconulid, which is a small cusp sandwiched between the entoconid and the hypoconulid. The pattern created by the grooves separating the cusps is classically termed the Y-5 pattern, because the groove separating the lingual and buccal cusp rows bifurcates into two grooves which course around the hypoconulid in a Y-shaped pattern.  However, this groove pattern is variable, and only occurs on teeth which actually bear a hypoconulid. It is just as difficult to distinguish M1 and M2 ­as it is for their maxillary counterparts.  As for maxillary molars, the mandibular molars usually decrease in size from M­1-M3.  M2 more frequently lacks a hypoconulid than M1.

Siding Molars

Molar teeth can usually be unambiguously sided.  Identification of the cusps is the key to siding molars.  Once a single cusp has been identified, reference the above descriptions to determine where on the tooth crown that cusp is located (e.g. the protocone is the mesial-lingual cusp).  Once the tooth has been roughly oriented in this manner, the identity of other cusps can be worked out, and the tooth may be easily sided. The protocone and protoconid are usually the largest and most heavily worn cusps.  When present, the hypocone is the smallest cusp on the upper molars.  Likewise, the hypoconid is usually the smallest cusp. The buccal and lingual cusp rows are unequal in height.  In the maxillary molars, the buccal cusp row is higher than the lingual.  In mandibular tooth rows, the lingual row is higher.  The roots of all molars have a tendency to tilt distally.


The occlusal outline of mandibular molars varies from square to a mesio-distally elongate oval.  Typical mandibular molars bear two roots, but occasionally three-rooted variants occur.  The two roots are often fused together. Mandibular molars bear four major cusps, arranged symmetrically around the major axes of the tooth. Lower molars often possess a smaller fifth cusp, and more rarely, a sixth cusp.  The four primary mandibular cusps are arranged in buccal and lingual rows, as in the maxillary molars.  The two major lingual cusps are the metaconid (mesial) and the entoconid (distal).  The two major buccal cusps are the protoconid (mesial) and the hypoconid (distal). The frequently present fifth cusp is the hypoconulid (more distal than the hypoconid). In some teeth, the hypoconulid is positioned more near the buccal-lingual midline; more commonly it is offset buccally toward the hypoconid.  When six cusps are present, the additional cusp is usually the entoconulid, which is a small cusp sandwiched between the entoconid and the hypoconulid. The pattern created by the grooves separating the cusps is classically termed the Y-5 pattern, because the groove separating the lingual and buccal cusp rows bifurcates into two grooves which course around the hypoconulid in a Y-shaped pattern.  However, this groove pattern is variable, and only occurs on teeth which actually bear a hypoconulid. It is just as difficult to distinguish M1 and M2 ­as it is for their maxillary counterparts.  As for maxillary molars, the mandibular molars usually decrease in size from M­1-M3.  M2 more frequently lacks a hypoconulid than M1.

Siding Molars

Molar teeth can usually be unambiguously sided.  Identification of the cusps is the key to siding molars.  Once a single cusp has been identified, reference the above descriptions to determine where on the tooth crown that cusp is located (e.g. the protocone is the mesial-lingual cusp).  Once the tooth has been roughly oriented in this manner, the identity of other cusps can be worked out, and the tooth may be easily sided. The protocone and protoconid are usually the largest and most heavily worn cusps.  When present, the hypocone is the smallest cusp on the upper molars.  Likewise, the hypoconid is usually the smallest cusp. The buccal and lingual cusp rows are unequal in height.  In the maxillary molars, the buccal cusp row is higher than the lingual.  In mandibular tooth rows, the lingual row is higher.  The roots of all molars have a tendency to tilt distally.


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