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Silicone tubes filled with EndoRez, a methacrylate-based root canal sealer, were implanted in the subcutaneous connective tissue of the rat. Solid, silicone rods of the same size as the tubes also were implanted and used as negative controls. The tissue reaction to test and control materials was histologically studied and analyzed by elemental electron-microprobe analysis. After 10, 30, 90, and 120 days of implantation, different grades of tissue reaction to the tested materials were recorded. A granulomatous tissue containing numerous polymorphonuclear leukocytes, lymphocytes, and plasmocytes, as well as macrophages and foreign-body giant cells with engulfed material in their cytoplasm, was initially observed in contact with EndoRez. Fibroblasts and newly formed vessels also were observed. This cellular profile persisted after 30 days. The severity of the reaction decreased with time, and connective tissue healing was observed at the 120-day observation period, even though some specimens exhibited a slight, persistent, inflammatory cell infiltration. The electron-microprobe analysis of the tissues revealed the presence of heavy components of EndoRez in all observation periods. In contact with the controls, there was an initially slight concentration of inflammatory cells. This reaction rapidly subsided after 30 days, and a fibrous connective tissue encapsulation, free of inflammatory cells, could be observed at the 90- and 120-day observation periods.

Under the experimental conditions, AET instruments and manual instrumentation with Hedström files resulted in cleaner canals. However, completely clean root canal walls were not produced with any of the techniques investigated.

Although better instrumentation scores were obtained in canals prepared with AET, complete cleanliness was not achieved by any of the techniques and instruments investigated.

Calcium hydroxide is widely used as a root canal dressing material because of its favorable alkalinizing effect. It has been suggested that the action comes from diffusion of hydroxyl ions through the apical foramen. The purpose of this in vitro study was to test the pH changes that occurred over a period of 30 days using a mixture of calcium hydroxide and distilled water and two commercial calcium hydroxide products in a simulated periapical environment. The materials were inserted in glass tubes closed at one end, which were placed in individual vials containing distilled water at a pH 7.4. Unfilled glass tubes were used as controls. Alkalinity changes of the medium were measured at 1 and 24 h and 15 and 30 days. The alkalinizing properties of all materials showed a rapid increase at 1 and 24 h followed by a continuous but more gradual increase from 15 to 30 days. The control tubes did not cause a change in pH of the medium, which remained at pH 7.4. At the end of the observation period, the alkalinizing properties of Calasept and Ultracal XS were significantly higher (P < 0.05) than the calcium hydroxide/distilled water paste.

No abstract

It was concluded that the Tri Auto ZX was useful and reliable. The Tri Auto ZX measurements protected against overpreparation.

No abstract