Third Molars: Wisdom of Wisdom Teeth

• __ _____ third molars are extracted from approximately __ ____ people in the U.S. each year at an approximate annual cost of over __ ____

• Formation of third molars begins at dental age __

• Crown formation is completed at age __

• 10 Million third molars are extracted from approximately 5 million people in the U.S. each year at an approximate annual cost of over 3 billion

• Formation of third molars begins at dental age 12

• Crown formation is completed at age 15

Can 3rd Molars be useful?

• Auto transplantation to replace missing teeth

  

• Shift into position of missing 2nd molar

  

Mythology of Third Molars

1. Impacted third Molars Have high incidence of pathology

   • Incidence is only 12%, which is compared to appendicitis at 10%, is not high enough to justify surgical intervention

2. Early removal is less traumatic

   • Early removal of asymptomatic impacted molars is more traumatic than leaving them

     • Pain, swelling, bruising, malaise, dry socket, secondary infection, paresthesia

3. Pressure of erupting third molars causes crowding of anterior teeth

   • Association, not causation

4. The risk of pathology in impacted third molars increases with age

   • Only 0.81% experienced cystic formation for 23 years

5. There is little risk or harm in the removal of third molars

   • Pain, swelling, bruising, malaise, dry socket, secondary infection, paresthesia, fracture, neuralgia

T/F The practice of prophylactic removal of pathology-free impacted third molars should be discontinued as there is no evidence to support a health benefit to patients from the prophylactic removal of pathology-free impacted teeth

T

What are reasons for third molar impaction, rank from highest to lowest impacts

1. Vertical direction of condylar growth

2. Reduced mandible length

3. Backward-directed eruption of the mandibular dentition

4. Retarded maturation of third molars

What are good indicators that tell you third molars will be impacted?

1. Long ascending ramus

2. Short mandibular length

3. Greater mesial crown inclinations of third molars

Prediction of space available

• Cephalometric predictors at 8-9: insufficiently reliable, only works 58% of the time

• Inclination of third molar at pre- adolescence: no predictive value

Consensus

• Little rationale for extraction solely to minimize crowding

• Orthodontic therapy with posterior movement can result in impaction of third molars

• Third molars are not needed for basal skeletal components

• Post-op pain, swelling, infection can be minimized by removing third molars in young pt when roots are only 2/3 developed

• Enucleation of 3rd molar buds based on measurements obtained age 7-9 is not acceptable