Intrusion Injuries of Primary Incisors. Part III: Effects on the Permanent Successors

Resident: Adam J. Bottrill
Date: 10SEP
Region: Providence
Article title: Intrusion Injuries of Primary Incisors. Part III: Effects on the Permanent Successors
Author(s):Diab, Mai DDS et al.
Journal: Quintessence International
Page #s: 377-384
Year: 2000:30
Major topic: Intrusion Injuries
Minor topic(s): NA
Type of Article: Analysis of Intrusion Injury Characteristics
Main Purpose: Analyze the effects of intrusion injury of primary incisors on the permanent dentision.

Key points in the article discussion:

I. General:

A. The potential for disturbances of the developing permanent dentition is high following injuries to their predecessors. (12-74% ???)

B. 18-69% (????) of permanent developmental defects due to INTRUSION injuries of primary teeth.

II. Factors Influencing the Sequelae of Intrusion Injuries.

A. Age of child:
1. Before 3yo, crown formation can be effected. (enamel hypoplasia, coronal dilaceration, odontoma etc...)
2. After 3yo, typically, root formation effected.
3. Typically, younger=more potential for permanent injury.
4. Germ can still suffer mineralization disturbances even after crown is fully formed.

B. Direction of intrusion:
1. Most risk when intrusion forces crown labially and root palatally.

C. Severity of Intrusion:
1. Increased severity = increased chance of damage
2. Alveolar fracture also increases chance.

D. Type of Treatment:
1. Several studies report that there is no correlation between severity of damage and the decision to extract versus allow to re-erupt.
2. Injury to the tooth is sustained at time of intrusion and not dependent on subsequent extraction.
3. The only exception to this rule is when subsequent infection occurs to intruded primary tooth.

III. Sequelae affecting coronal portions of the permanent successor:

A. White or yellow brown discoloration
1. Intrusion of primary teeth during mineralization of permanent crowns between 2-7yo.
2. Result of hypocalcified areas of the labial surface. (during "maturation" stage)
3. Bleeding may also hemoglobin products to enter the mineralizing portion of the enamel.

B. White of yellow-brown discoloration associated with enamel hypoplasia
1. "imperfect formation" due to injury between 2-3yo
2. displacement of the normal alignment of the ameloblast activity
3. irreversible destruction of the active enamel epithelium
4. grooves may form around the discoloration

C. Dilaceration of the crown:
1. Typically due to intrusion injury at around 2yo. (when 1/2 the crown is formed.
2. Displaced enamel epithelium becomes activated in a new/displaced position.
3. May erupt normally but will likely necrose... prophylactic crown recommended to avoid abscess.

IV. Sequelae Affecting Rot Portions of the Permanent Successors:

A. Duplication:
1. Rare malformation usually occurs from severe intrusion at around 2yo.

B. Dilaceration of the root:
1. Intrusion between 2-5yo.
2. Displaced hard tissue relative to the developing root... likely to be impacted.
3. Lateral dilaceration occurs between 2-7yo and usually tooth erupts normally.

C. Partial or complete cessation of root formation:
1. Rare sequelae due to intrusion between 4-7yo.
2. Hertwig's epithelial root sheath damaged.

V. Sequelae affecting the whole successor tooth:

A. Odontomalike malformation:
1. Severe intrusion of primary incisor between 1-3yo. (early stages of odontogenesis)
2. Require surgical extraction.

B. Sequestration of the permanent tooth germ:
1. Underdeveloped tooth germ and inadequate rot formation.
2. RARE... caused by SEVERE intrusion.
3. Also related to severe periradicular infection
4. Surgical extraction.

C. Disturbances of permanent successor eruption:
1. Early primary tooth loss (3-4yo) can cause delay in permanent successor eruption
2. Primary tooth loss later than 5yo can accelerate permanent eruption.
2. Ankylosed or delayed root resorption can also cause delayed eruption.

VI. Conclusion:

A. High probability of permanent tooth damage when primary tooth is intruded.
B. If the "wait and see" method is chosen... periodic recall is necessary to avoid periradicular infection and probably permanent tooth damage.

Assessment of article: Informative... BUT, the bottom line is, the permanent tooth is likely to be damaged. Knowing all the percentages of the type of sequelae doesn't really help me because it doesn't change treatment options. Also... despite the information presentd, I'm extracting the primary tooth if it's intruded. Not taking chances WRT subsequent infection.