Permanent Molars Development and Morphology

Permanent Molars

Development

• Permanent molars start developing between 4-5 years old
• They begin to erupt between 6-12 years old
• Root development is complete around 12-14 years old

Morphology

• Crown shape: Quadrangular, with a flat or slightly rounded occlusal surface
• Cusps: 4-5 cusps: mesiobuccal, mesiolingual, distobuccal, distolingual, and a smaller cusp on the lingual surface
• Grooves: Central fossa, mesial and distal developmental grooves, and buccal and lingual grooves
• Roots: 2-3 roots (mesiobuccal, distobuccal, and lingual) that are fused together

Types

• First molars: Larger than second molars, with a larger crown and more developed roots
• Second molars: Smaller than first molars, with a smaller crown and less developed roots
• Third molars (wisdom teeth): Smaller than second molars, with a variable shape and root development

Occlusal Surface

• Cuspal inclines: Sloping surfaces of the cusps that meet at the central fossa
• Fossa: A depression in the center of the occlusal surface
• Triangular ridges: Elevated areas that connect the cusps to the central fossa

Clinical Considerations

• Eruption sequence: Typically, the first molars erupt around 6 years old, followed by the second molars around 12 years old, and the third molars (wisdom teeth) between 17-25 years old
• Impaction: Third molars may be impacted due to insufficient space in the dental arch

Permanent Molars

• Start developing between 4-5 years old and begin to erupt between 6-12 years old
• Root development is complete around 12-14 years old

Morphology

• Crown shape is quadrangular with a flat or slightly rounded occlusal surface
• Has 4-5 cusps: mesiobuccal, mesiolingual, distobuccal, distolingual, and a smaller cusp on the lingual surface
• Features central fossa, mesial and distal developmental grooves, and buccal and lingual grooves
• Roots are 2-3 fused roots: mesiobuccal, distobuccal, and lingual

Types

• First molars are larger with a larger crown and more developed roots
• Second molars are smaller with a smaller crown and less developed roots
• Third molars (wisdom teeth) are smaller with a variable shape and root development

Occlusal Surface

• Cuspal inclines are sloping surfaces of the cusps that meet at the central fossa
• Fossa is a depression in the center of the occlusal surface
• Triangular ridges are elevated areas that connect the cusps to the central fossa

Clinical Considerations

• Eruption sequence: first molars erupt around 6 years old, second molars around 12 years old, and third molars between 17-25 years old
• Third molars may be impacted due to insufficient space in the dental arch

Tooth Structure

• Enamel is the hard outer layer of a tooth, making it the hardest substance in the human body
• Dentin is the layer beneath enamel, composing most of the tooth structure
• Cementum is a thin layer covering the root surface of a tooth
• Pulp is the soft tissue containing nerves and blood vessels within a tooth
• Permanent molars have a larger pulp chamber and thicker dentin compared to primary molars

Occlusal Development

• Permanent molars start forming around 4-5 years old
• They continue developing until around 12-13 years old
• Roots of permanent molars continue to mature until around 15-16 years old

Morphology

• Permanent molars have 4-5 cusps and a larger occlusal surface than primary molars
• They have a more complex root structure than primary molars
• First molars have a larger mesiodistal diameter than second molars
• Third molars have a smaller occlusal surface and fewer roots than first and second molars

Dental Anatomy

• Permanent molars are located in the posterior region of the mouth
• First molars erupt around 6-7 years old
• Second molars erupt around 12-13 years old
• Third molars erupt around 17-25 years old
• Permanent molars are larger than primary molars and have a more complex occlusal surface

Eruption Patterns

• Permanent molars erupt in the following order: first molars, second molars, and third molars
• First molars erupt around 6-7 years old, second molars around 12-13 years old, and third molars around 17-25 years old
• Eruption patterns can vary, but generally follow this order and age range