Differentiating Right and Left Human Permanent Teeth

Difference between right and left teeth Permanent teeth:

Maxillary central incisors:

When viewed from the labial aspect, the distal incisal angle is more rounded than the mesial.

In many specimens, a cross-section mid-root reveals a right triangle outline with the hypotenuse is toward the mesial.

Maxillary lateral incisors:

The distoincisal angle is more rounded than the mesial incisal angle.

The tip of the root may incline distally, but this is not a consistent finding.

Mandibular central incisors:

The symmetry of this tooth makes a judgment on right and left unreliable.

Mandibular lateral incisors:

Two significant features assist in identification, even in a worn tooth.

-The incisal edge is 'twisted' relative to a line passing from the labial to the lingual anticipating the curvature of the dental arch.

-The cingulum will be shifted toward the side from where the tooth has come.

Maxillary and mandibular canine

-The distal surface is fuller and more convex than the mesial surface.

Maxillary first premolar                                                                                          

Two distinctive traits help is distinguishing right and left.

-The mesial developmental depression and the mesially displaced lingual cups tips are consistent clues for determining right and left.

-When well defined, the mesial marginal ridge is also a clue to right and left          

Maxillary second premolar

The one consistent clue to right and left is the lingual cusp tip which is shifted mesially.

Mandibular first premolar

-The larger distal occlusal fossa and mesial lingual marginal developmental groove are consistent clues to right and left.

-The distal surface has a longer radius of curvature than does the mesial surface.

Mandibular second premolar

In the two cusp version, the lingual cusp tip is shifted mesially.

In the three cusp version, the larger of the two lingual cusps is to the mesial.

Maxillary first molar

-The large mesiolingual cusp,

-Single large lingual (palatal) root,

-Carabelli trait makes distinguishing right and left easy                                                        

Maxillary Second Permanent Molar

-The large mesiolingual cusp

-Small distolingual cusp

-Three roots (larger palatal) make distinguishing right and left easy.

Mandibular First Permanent Molar

The cervical ridge on the buccal aspect, the two buccal cusps located to the buccal along with the distal cusp provide identification of the buccal aspect.

The distal cusp is the smallest and is displaced along the occlusal aspect. These features make possible identification of right and left.

Mandibular Second Molar

When viewed occlusally, there is a distinctive prominence of enamel at the mesiobuccal--a feature shared with first deciduous molars.

Examined from the mesial or distal, the lingual surface has its height of curvature midway between the occlusal and the cervical line.

On the buccal surface, the height of curvature is at the gingival third--near the cervical line.