AIM: The purpose of this study was to describe the external and internal anatomy of the mandibular premolars. MATERIAL AND METHODS: 100 extracted human permanent mandibular first and second premolars teeth were collected. The length of the tooth from the cusp tip to root apex was measured with the help of Vernier calliper. In case of curved roots, ligature wire was adapted to the root and then straightened and measured. Each tooth was examined for the number of roots, curvature of root, presence of root canal invagination. India ink was injected into the pulp chamber through the access opening with a no.27 gauge needle mounted on a disposable syringe. The ink was then drawn through the root canal system by applying negative pressure to the apical end of tooth with the use of central suction system. RESULTS: The average (mean) length of mandibular first premolar was 22.25 mm. Average (mean) length of mandibular second premolar was 21.90 mm. Mandibular first premolar had a ribbon shaped root canal orifice in 35% of teeth. Mandibular second premolar had a ribbon shaped of root canal orifice in 44% teeth. Mesial invagination of the root was found in 18% of first and 8% second mandibular premolar teeth. 78% had a Type I canal pattern with Type II, Type IV, Type V, Type VI and Type VII canals being identified in 1%, 2%, 13%, 2% and 1% of the teeth respectively. CONCLUSIONS: Complex root canal anatomy frequently found with mandibular premolars among which more common with mandibular first premolars in Indian population.

Regenerative Endodontic Procedures can be defined as biologically based procedures designed to replace damaged structures including dentin and cells of the pulp – dentin complex. The term revascularization is more commonly employed with regenerative procedures and describes reintroduction of vasculature in the root canal system. This case report describes the treatment of two nonvital immature teeth with infected pulp. Revitalization was attempted in two adjacent teeth by the same operator following similar protocol. In one of the teeth, revitalization was successful with continued root wall thickening, root lengthening and closure of the apex whereas in the adjacent tooth though root lengthening could not be achieved, a definite apical closure with irregular root wall thickening could be obtained.