Abstract
Abstract : This article describes that great care is needed to treat mandibular premolars endodontically. The patient was a 9-year-old Japanese boy who had incompletely formed roots of the permanent mandibular left second premolar with a central cusp-like structure (dens evaginatus). The tooth had radiographically two well-differentiated roots (1 mesial and 1 distal). Clinical and radiographic examinations of the tooth revealed an acute periapical abscessed lesion and blunderbuss canals with resultant pulp necrosis. Pain was both spontaneous and severe, as well as long-lasting for a few days. The tooth and the adjacent molars were tender to touch.
At the first visit to our university hospital clinic, pain, swelling, and other symptoms had almost disappeared. The canal space had been opened without anesthesia by another dentist. In the canals, a cotton pellet moistened with Calvital had been sealed into the pulp chamber with zinc oxide eugenol cement. Routine apexification procedures with calcium hydroxide were used for the tooth.
The patient has done well for three years. Although the radicular pulp did not maintain vitality, apical closure occurred almost normally at approximately two years after the root canal treatment. A calcified barrier that formed across the open apices of the three root canals was detected by careful examination by touch, use of a surgical microscope, measuremet of impedance, and replica technique. The end of the roots seemed to have increased a few millimeters in length.
We have the view that once the environment of the periapex has been improved, even where little pulp tissue remains, a Hertwig’s epithelial root sheath can continue to function with subsequent root maturation.
