Topics

Topic

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Inferior second molar tooth

The inferior second molar is the second posterior tooth in the mandibular dental arch on each side, located between the first molar anteriorly and the third molar (if present) posteriorly. It typically has two roots (mesial and distal), although root morphology can vary, and a broad occlusal surface with multiple cusps for grinding food. Its crown usually has five cusps—three buccal and two lingual. The pulp chamber, root canals, and periodontal ligament are critical structures for dental interventions such as fillings, root canal treatment, and extractions. The inferior second molar is key for mastication, maintaining occlusal stability, and preserving arch integrity.

Synonyms

  • Mandibular second molar

  • Lower second molar

  • Tooth 37 / 47 (FDI notation)

  • Permanent mandibular second molar

Function

  • Provides grinding and mastication of food

  • Maintains posterior occlusion and supports bite alignment

  • Serves as an anchor for dental prosthetics if adjacent teeth are missing

  • Contributes to facial height and mandibular stability

MRI Appearance
T1-weighted images:

  • Enamel appears very low signal (hypointense) due to its mineral content

  • Dentin shows intermediate signal, and the pulp chamber is hyperintense due to its soft tissue content

  • Surrounding periodontal ligament space appears as a thin hypointense line around the roots

  • Pathological changes such as pulpitis or periapical lesions may appear as altered signal intensity in the pulp or periapical region

T2-weighted images:

  • Pulp chamber and root canals are hyperintense, contrasting with hypointense enamel and intermediate dentin

  • Useful for detecting edema, pulp necrosis, or inflammatory changes

STIR (Short Tau Inversion Recovery):

  • Suppresses surrounding fat signal, highlighting periapical inflammation or cystic lesions

  • Normal tooth structures remain distinct, while infected or edematous tissue appears hyperintense

CT Appearance

  • Enamel appears hyperdense (bright white), dentin slightly less dense

  • Pulp chamber and root canals are hypodense relative to hard tissue, clearly delineated

  • Surrounding alveolar bone is visible for evaluation of bone loss, fractures, or periapical pathology

  • CT is particularly useful for implant planning, evaluating complex root morphology, and detecting calcifications or impacted adjacent teeth

MRI images

Inferior second molar tooth mri axial image -img-00000-00000

MRI images

Inferior second molar tooth mri sag image -img-00000-00000