Pulp and root development after partial extrusion in immature rat molars: a histopathological study

Area of Science:

• Dentistry
• Oral Biology
• Regenerative Medicine

Background:

• Partial extrusion injuries in immature teeth present unique challenges for pulp healing and root development.
• Understanding the pulpal response to trauma is crucial for predicting treatment outcomes.

Purpose of the Study:

• To investigate the relationship between root development stage and the histopathological response of immature rat molar pulp following partial extrusion.
• To evaluate the long-term effects of partial extrusion on pulpal tissue and root apex formation.

Main Methods:

• Immature rat molar teeth underwent partial extrusion at different root formation stages (1/2, 2/3, 3/4).
• Histopathological analysis and Scanning Electron Microscopy (SEM) were used to examine pulpal tissue changes.
• Rats were observed at multiple time points post-injury (immediately, 3, 7, 14, 30, 60 days).

Main Results:

• Extrusive injury caused odontoblast layer ablation and pulp bleeding, evident as erythrocytes and leukocytes.
• Odontoblast layer damage was most frequent in the pulp horn, cervical area, and chamber floor.
• Pulp reactions were more severe in teeth with more complete root formation compared to those with less complete formation.

Conclusions:

• The degree of root development significantly influences the pulpal response to partial extrusion.
• More complete root formation leads to a greater adverse effect on the pulp after extrusion.
• Less complete root formation is associated with increased malformation of the root apices post-extrusion.