Wisdom Teeth Eruption: Timeline, Impaction Signs & When to Extract

Third molars (wisdom teeth) typically erupt ages 17–25, but variation is wide.

Eruption Patterns

• Normal: Fully erupt, functional, cleansable. ~30–40%.
• Impaction (no eruption): Soft tissue, partial bony, full bony. ~60–70%.
• Agenesis: Congenitally missing (1 or more). ~20–25%.
• Ectopic: Malpositioned (horizontal, distal, mesioangular).

Indications for Extraction (AAOMS)

• Pathology: pericoronitis (recurrent), caries (2nd molar), periodontal defect, cyst/tumor.
• Symptomatic: pain, swelling, trismus, infection.
• Orthodontic: interference with alignment, relapse risk.
• Prophylactic: asymptomatic impacted – controversial; consider age (<25 better healing), pathology risk, patient preference.

Optimal Timing

• Roots ½–⅔ formed (typically 16–20 yr) → easier surgery, faster healing, lower nerve injury risk.
• Before orthodontic completion if needed.

Risks

• Inferior alveolar nerve (IAN) injury → temporary/permanent lip/chin paresthesia (1–5%).
• Lingual nerve injury (taste/tongue sensation) – rare.
• Dry socket (alveolar osteitis) – 5–30% (lower > upper; smokers ↑).
• Sinus communication (upper).

Decision Framework

Panoramic/CBCT → risk stratification → shared decision. Not all need removal; monitor asymptomatic with periodic imaging.