Traumatic injury to primary tooth leads to intrusion. After how much time, the tooth usually re-erupts?

 # Traumatic injury to primary tooth leads to intrusion. After how much time, the tooth usually re-erupts?

a) 30 days

b) 3 months

c) 6 months

d) 12 months

The correct answer is C. 6 months.

Explanation:

Intrusion of a primary tooth occurs when a traumatic force displaces the tooth apically into the alveolar bone. The potential for re-eruption depends on factors such as the degree of intrusion, the integrity of the periodontal ligament, the child's age, and the absence of complications like ankylosis or damage to the underlying permanent tooth bud. In pediatric dentistry, re-eruption is a common outcome for intruded primary teeth due to the elasticity of the periodontal ligament and ongoing alveolar growth.

While some studies suggest re-eruption can occur within 2–4 months for mild to moderate intrusions, the 6-month timeframe is more plausible in clinical practice for several reasons:

Variable Healing Dynamics: Moderate to severe intrusions may require longer for the periodontal ligament to reorganize and facilitate re-eruption, especially if there is initial swelling or minor alveolar bone remodeling.

Clinical Monitoring Period: Dentists often observe intruded teeth for up to 6 months to confirm complete re-eruption or to detect complications (e.g., failure to re-erupt, ankylosis, or pulpal necrosis). The 6-month mark is a standard endpoint in guidelines (e.g., American Academy of Pediatric Dentistry) for assessing outcomes.

Conservative Estimate: The 6-month duration accounts for cases where re-eruption is slower due to partial intrusion or minor displacement, ensuring the tooth returns to its original position without intervention.

In contrast, 30 days is too short for complete re-eruption, as initial healing and tissue reorganization take longer. 3 months may suffice for milder cases but may not cover the full spectrum of intrusion severities. 12 months is excessively long unless complications delay the process significantly. Thus, 6 months is a clinically relevant and plausible timeframe for the re-eruption of most intruded primary teeth, balancing biological healing with practical observation periods.