Purpose: to describe by histological and scanning electron microscopic (SEM) technique the tissue regeneration and response around two bonded retrograde composite fillings placed in humans.
Case 1 and 2:
•Two males, 31 and 28 yr old, were treated for root fractures of upper incisors.
•As part of this treatment retrograde dentin-bonded composite resins were placed to cover the resected apical root surface.
•In both cases the teeth had to be removed 3 yr afterward due to a fracture in the first case and marginal infection in the second.
•The apical fragments were removed along with a narrow zone of surrounding bone.
•The specimens were examined histologically and by SEM.
•Histological and SEM examinations showed reformation of periodontium adjacent to the composite, including reformation of a lamina dura, inserting Sharpey’s fibers and cementum deposited in intimate contact with the composite.
the finding of these 2 cases indicate that tissue regeneration including cementogenesis may occur on composite material and consequently form a biological closure of the root canal.
FIG 1. A, Radiographic appearance of right lateral incisor 3 yr after retrograde root filling with dentin-bonded composite. A second root fracture necessitated removal.
B, The apex was removed separately along with periapical bone. A lateral radiograph of the specimen illustrates healing.
C, An axial histological section illustrates intact labial bone reformation of a periodontal ligament. The empty space represents the lumen after the composite was lost during preparation of the section (original magnification x25).
D, Higher magnification of the boxed area showing deposition of cementum upon the composite and reformation of fibers very likely to be Sharpey’s fibers (original magnification x90).
E, Higher magnification showing invasion of silver stained composite in dentinal tubules (original magnification Å~190).